Dissertations / Theses on the topic 'Effluent Treatment Plant Sludge'

The objective of this study was to investigate the anaerobic biological treatment of an organic-bearing wastewater from a particular paper manufacturing process at laboratory scale. The process produces paper by re-pulping waste paper. Effluent from the process has a Chemical Oxygen Demand (COD) concentration of approximately 4500 mg/l with a sulphate content of approximately 300 mg SO₄²⁻/l. The upflow anaerobic sludge bed (UASB) reactor was selected for the study. Important information derived from the laboratory treatability study was: (l) the extent of COD removal possible; (2) the effluent quality; (3) the maximum COD leading rate (kgCOD/m³ reactor/day) which can be achieved while maintaining reasonable COD removal, and the influence on loading rate of temperature: (4) the nature of the sludge produced in the reactor with particular reference to the extent of pelletisation: and (5) the effect of reactor effluent recycling on alkalinity requirements.

Dissertation to obtain the degree of Master in Chemical and Biochemical Engineering
The work present in this thesis was conducted in Portucel Soporcel mill, in the industrial complex of Setúbal, and had as main objective the modelling of the treatment process of the effluents from this industry, using for this purpose the software GPS-X. This program has a clear-cut graphical interface and uses a specialized translator that converts the graphical process into material balance equations, based on dynamic models. These models allow, besides the kinetic descripton of the treatment process carried out at the WWTP, to simulate new scenarios towards the study of critical parameters for the process as well as optimization and control of the WWTP. The effluent that arrives to Portucel’s WWTP, from the pulp and paper mills of the complex, is particularly rich on fibers (solids), lignin, chlorinated and sulphur compounds, resin acids, phenols and starch. It has a brown colour due to the presence of lignin and has a high oxygen chemical demand (about 1,095 g O2/m3). The WWTP uses the activated sludge process with extended aeration. This method allows an efficient removal of organics at the same time as it minimizes the sludge production. For the modelling of the process it was necessary to collect historical data related to the WWTP’s performance over the last 3 years. This data was used as input values for the influent characterisation and as output values to achieve the treated effluent characterisation. Since the first simulation did not lead to the desired output results, it was necessary to proceed to the model calibration, by means of a more detailed study concerning the nutrient and organic fractions of the influent. Once the model was calibrated, a study of the urea flowrate was conducted. The urea is added to the influent, before the beginning of the biological oxidation, as a way to satisfy the nitrogen requirements along the treatment process. However, this flowrate was never submitted to a study that evaluated, in a higher detail, the effective requirements of this nutrient. Thus, some simulations were done using the software, by decreasing successively the value of the urea flowrate and the results obtained were analyzed. Furthermore, these simulations were validated in the WWTP itself, at Portucel, through the decrease of the urea flowrate to half the normal value. Both the simulations and Portucel’s results showed that, actually, the addition of urea is not necessary because it does not affect the treatment process in a significant way, namely in terms of the removal of chemical oxygen demand. The simulations have also showed that the concentration of nitrogen in the final effluent diminishes significantly with the reduction of the urea flowrate, which could be advantageous in an environmental point of view.

The increasing cost of effluent treatment in the wool scouring industry is rapidly becoming a determining factor in the viability of existing scouring operations and new installations alike. This thesis details the development of an integrated effluent treatment process capable of treating the worst polluted effluent from a wool scour "heavy flow-down", to the point where it can either be economically discharged to local trade waste sewer, or directly discharged to river or ocean outfall with minimal environmental impact. The existing proprietary chemical flocculation process, Sirolan CF™, was improved by the addition of a bio-flocculation stage and turbidity monitoring and control, and the product from this process fed to an aerobic biological treatment system based upon the traditional activated sludge process. The biological treatment process was found to remove up to 98% of the BOD5 loading from the pre-treated liquor with a hydraulic residence time of at least 50 hours being required in the aerobic digestion vessels. A residual biorefractory COD of approximately 3,600mg/L was identified which could not be removed by biological treatment. When operating continuously, the biological process was observed to metabolically neutralise the pH 3.0 - 4.5 feed from the chemical flocculation system to pH > 7.0 without the need for supplemental addition of neutralising agents such as sodium hydroxide. This in itself provides a significant economic incentive for implementation of the process. Kinetic analysis of the biological process carried out under controlled laboratory conditions using a Bioflo 3000 continuous fermentor showed that the bio-chemical process followed substrate inhibition kinetics. An appropriate kinetic model was identified to represent the behaviour of the substrate degradation system, and modified by inclusion of a pseudo toxic concentration to account for the effect of pH inhibition upon the biological growth rate. The process was verified both at pilot plant scale and at demonstration plant scale at an operational wool scour. The demonstration plant was of sufficient size to handle the full heavy effluent flow-down from a small wool scour. At the time of publishing three full-scale effluent treatment systems based on this research had been sold to both domestic and international clients of ADM Group Ltd. who funded the research.

The discharge of untreated aquaculture effluent can pollute receiving water bodies. I tested the feasibility of using salt-tolerant plants (halophytes) with potential as forage and oilseed crops, as biofilters to treat saline aquaculture effluent. Plants were grown in draining lysimeters in greenhouses and irrigated with effluent salinized with NaCl. Irrigation water came from a recirculating tilapia culture system. I measured yield potential, water use and capacity for nitrogen and phosphorus uptake. In Experiment 1, Suaeda esteroa, Salicornia bigelovii and Atriplex barclayana (Chenopodiaceae) were grown in sand in 0.02 m³ lysimeters. Plants were irrigated with effluent of 0.5 ppt, 10 ppt and 35 ppt salinity, to meet evapotranspiration demand and to allow 30% of the applied water to leach past the plant root zone. Despite the high leaching fraction and short residence time of water in the pots, the plant-soil system removed 98% and 94% of the applied total and inorganic nitrogen, respectively, and 99% and 97% of the applied total and soluble reactive phosphorus respectively. For all species, salt inhibited (P ≤ 0.05) the growth rate, nutrient removal, and volume of water the plants could process. The salt marsh species S. esteroa and S. bigelovii performed better than the desert saltbush, A. barclayana, at 35 ppt. In Experiment 2, Suaeda esteroa, was grown in lysimeters containing approximately 0.8 m³ sandy loam soil and irrigated three times per week with 31 ppt NaCl effluent. I used five irrigation treatments, ranging in volume from 50 to 250% of the potential evaporation rate. Plant biomass and water consumption increased significantly (P ≤ 0.05) with increasing irrigation volume. Nitrate concentrations in water draining from the lysimeters decreased during the experiment, and were significantly lower in the high-volume treatments than in the low-volume treatments. Phosphorus concentrations in the leachate water increased during the experiment as a function of increasing irrigation volume. Irrigating halophyte crops with aquaculture wastewater of seawater-salinity may be a viable strategy for disposal of effluent.

Studies were conducted to determine the role of bioflocculation in the activated sludge unit processes. Laboratory and full-scale studies revealed that bioflocculation is important in determining settling, dewatering, effluent and digested sludge properties (activated sludge properties) and may be vital to the function of all processes related to the above properties. In these studies, it was shown that divalent cations such as calcium and magnesium improved activated sludge properties, whereas monovalent cations such as sodium, potassium and ammonium ions were detrimental to these properties. The divalent cations promoted bioflocculation through charge bridging mechanisms with negatively charged biopolymers (mainly protein and polysaccharide). It was found that oxidized iron plays a major role in bioflocculation and determination of activated sludge properties through surface interactions between iron and biopolymers. Oxidized iron was effective in removing colloidal biopolymers from solution in coagulation and conditioning studies. The research included experiments evaluating effects of potassium and ammonium ions on settling and dewatering properties; effects of magnesium on settling properties; effects of sodium, potassium, calcium and magnesium on effluent quality; effect of solids retention time on effluent quality; and evaluation of floc properties during aerobic and thermophilic digestion. A floc model is proposed in which calcium, magnesium and iron are important to bioflocculation and the functionality of aeration tanks, settling tanks, dewatering equipment and aerobic or anaerobic digesters. It is shown that activated sludge floc properties affect wastewater treatment efficiency.
Ph. D.

Water treatment plant (WTP) residual discharge is considered a pollutant and requires treatment to prevent negative impacts when released to the environment. As regulatory requirement becomes increasingly strict, WTPs are required to find suitable methods for the treatment of sludge residuals. Wastewater treatment plants(WWTP) provide existing treatment methods to remove contaminants from WTP residuals. A case study on the Carbondale Water Treatment Plant (CWTP) and receiving Carbondale Southeast Waste Water Treatment Plant (SEWWTP) provided an opportunity to quantify potential negative impacts for the discharge of residual alum sludge to a biologic sludge digestion plant. The first part of the study focused on quantifying changes to the SEWWTP loading conditions from the addition of metal salt coagulant water treatment residuals discharged by the CWTP. Historic sludge quantities and treatment methodologies for both the CWTP and SEWWTP were used to predict loading conditions and residual concentrations at the SEWWTP. Ammonia, BOD, pH, and TSS concentrations from the CWTP were not identified to significantly impact the existing concentrations at the SEWWTP. Metals concentrations from the CWTP were also found to fall within WWTP regulatory quantities. The second part of the study evaluated potential impacts to beneficial bacteria populations in the SEWWTP oxidation ditch from the receipt of CWTP alum residuals. Studies of residual alum sludge impacts to beneficial bacterial populations are rare, and often do not translate from one treatment plants processes to the next. The SEWWTP employs a multi-ring oxidation ditch with an anoxic outer ring and aerobic middle and inner rings. Biologic Activity Reaction Tests (BART) were used to isolate beneficial bacteria species typically present in oxidation ditches including heterotrophic aerobic bacteria, denitrifying bacteria, and nitrifying bacteria. Heterotrophic aerobic bacteria and denitrifying bacteria are the predominant beneficial bacteria species in the outer ring, while nitrifying bacteria and heterotrophic aerobic bacteria dominate the aerobic inner rings. Heterotrophic aerobic bacteria and denitrifying bacteria populations identified in the outer ring of the oxidation ditch did not demonstrate any population impacts from the receipt of residual alum sludge. In addition, nitrifying bacteria populations and heterotrophic aerobic bacteria population demonstrated no impacts from the introduction of CWTP residual alum waste to the aerobic inner ring of the oxidation ditch. Overall, the study demonstrated the treatment of residual alum sludge from a WTP is possible through the existing biological processes at a WWTP.

It has been proven that microwave enhanced advanced oxidation process (MW-AOP) has an outstanding treatment efficiency on the organic slurries, such as sewage sludge and dairy manure (liquid portion), yet the treatment efficiencies on different substrates remain unknown. This study was carried out to: 1) identify the effects of MW-AOP on different types of sludge, 2) evaluate the effects of flowrates and solids concentrations on the heating profile, 3) evaluate the MW-AOP treatment efficiencies of secondary sludge at 90 and 110 ºC, and 4) examine the treatment efficiencies of MW-AOP of dairy manure (liquid portion). The study on the sludge was to evaluate treatment efficiencies of different sludge (primary sludge, secondary sludge, and anaerobic digested sludge) and the centrate by the MW-AOP. The results indicated that the secondary sludge was most suitable for the MW-AOP treatment. This is because secondary sludge had the highest number of solids and phosphorus contents, but also yielded the highest soluble materials. The pilot-scale 915 MHz MW-AOP system was used to treat the secondary sludge at 90 and 110ºC, which suggested that higher temperature would favor nutrients release. The dewaterability of treated sludge improved significantly at both temperatures. The pilot-scale 915 MHz continuous flow MW-AOP system was also tested with salt water at different flowrates and salt concentrations to understand the heating and power consumption profile of the system. Among the flowrates (6, 7.5, 9 L/min) and salt concentrations (10 mg/L to 120 mg/L) examined, the total energy consumption increased with an increase of salt concentration, while flowrates had lesser effect. In contrast, the temperature rise was more rapid with lower salt concentrations. The overall heating rate was similar for different flowrates. Similar to secondary sludge, the pilot-scale 915 MHz continuous flow MW-AOP system was used to treat dairy manure (liquid portion). The results suggested a sound treatment efficiency, with an increase from 3% to up to 90% of soluble TP/TP, which enhances subsequent struvite recovery. Both the ratios of soluble TP/TP and of ortho-P/soluble TP were favored by higher temperatures.
Applied Science, Faculty of
Civil Engineering, Department of
Graduate

Advanced wastewater treatment plants have complex biological kinetics, time variant influent rates and long processing times. The modeling and operation control of wastewater treatment plant gets complicated due to these characteristics. However, a robust operational system for a wastewater treatment plant is necessary to increase the efficiency of the plant, reduce energy cost and achieve environmental discharge limits. These discharge limits are set by the National Pollutant Discharge Elimination System (NPDES) for municipal and industrial wastewater treatment plants to limit the amount of nutrients being discharged into the aquatic systems. This document summarizes the research to develop a supervisory operational and control system for the Valrico Advanced Wastewater Treatment Plant (AWWTP) in the Hillsborough County, Florida. The Valrico AWWTP uses biological treatment process and has four oxidation ditches with extended aeration where simultaneous nitrification and denitrification (SND) takes place. Each oxidation ditch has its own anaerobic basin where in the absence of oxygen, the growth of microorganisms is controlled and which in return also helps in biological phosphorus removal. The principle objective of this research was to develop a working model for the Valrico AWWTP using BioWin which mimics the current performance of the plant, predicts the future effluent behavior and allows the operators to take control actions based on the effluent results to maintain the discharge permit limits. Influent and experimental data from online and offline sources were used to tune the BioWin model for the Valrico Plant. The validation and optimization of the BioWin model with plant data was done by running a series of simulations and carrying out sensitivity analysis on the model which also allowed the development of operation policies and control strategies. The control strategies were developed for the key variables such as aeration requirements in the oxidation ditch, recycle rates and wastage flow rates. A controller that manipulates the wasting flow rate based on the amount of mixed liquor suspended solids (MLSS) was incorporated in the model. The objective of this controller was to retain about 4500-4600 mg/L of MLSS in the oxidation ditch as it is maintained by the Valrico Plant. The Valrico AWWTP recycles around 80% of their effluent and hence, the split ratios were adjusted accordingly in the model to recycle the desired amount. The effluent concentrations from the BioWin model for the parameters such as Total Nitrogen (TN), Ammonia, Nitrate, Nitrite, Total Kjeldahl Nitrogen (TKN) complied with the discharge limits which is usually less than 2 mg/L for all the parameters.

Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2012.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 61-64).
This thesis is part of a larger project which began in response to a request by the Spanish water agengy, Cadagua, for advice on life cycle assessment (LCA) and environmental impacts of Cadagua operated wastewater treatment plants. The project uses the LCA software GaBi and focuses on La Gavia Wastewater Treatment Plant in Madrid. This thesis analyzes three sludge management options that La Gavia could have implemented: (1) cogeneration and incineration, (2) cogeneration and land application, and (3) Composting. Life cycle impacts of global warming potential, eutrophication, acidification, ozone layer depletion potential were calibrated using GaBi.
by Jong hyun Lim.
M.Eng.

The treatment of water for human consumption results in the production of residual waste flows that vary depending on source waters and water treatment technologies. Water treatment plant residual waste is defined as a pollutant that requires treatment either on site or through other means. Due to strict and evolving regulatory requirements, treatment of water treatment plant residual waste several common methods of disposing of water plant residuals exist including discharge to surface waters, discharge to sanitary sewers, and sanitary landfill disposal of dewatered wastes. Although originally discharged to the neighboring City Reservoir, the Carbondale Water Treatment Plant (CWTP) conducted an initial study to determine if plant residual waste could be treated at one of the City’s two wastewater treatment plants. No negative impacts were identified as part of this study and infrastructure was put in place to divert CWTP residual waste from the City Reservoir to the Carbondale Southeast Wastewater Treatment Plant (SEWWTP). This study focused on accessing and quantifying any impacts of Carbondale Water Treatment Plant (CWTP) residual solids sewer discharge on biological treatment processes, effluent water quality, and sludge production at the SEWWTP. The Carbondale SEWWTP treats raw water influent through a number of physical and biological processes including screening, clarification, nitrification/denitrification, and aeration. Of the tests run as part of this study daily samples were collected of SEWWTP influent, mixed liquor, return sludge, and effluent and measured for changes in pH, biochemical oxygen demand (BOD), solids, sludge volume index (SVI), dissolved oxygen (DO), and nitrogen. No significant changes were documented other than percent BOD removal did improve after the introduction of the residuals. Anions were also tested weekly. Samples were collected from the SEWWTP’s oxidation ditch to monitor biological life using biological activity reaction tests (BART) for nitrifying, denitrifying, and heterotrophically active bacteria. BART testing showed no decline in biological activity and increased populations of denitrifying bacteria. Additionally, both metals and acute toxicity of SEWWTP effluent were tested by outside testing facilities to confirm that CWTP residual solids sewer discharge did not interfere with discharge limits established as part of the plant’s permits. No significant changes were observed during testing but plant staff did indicate that more extensive cleaning of the basins was implemented post-introduction. Overall, the case study confirmed that the treatment of CWTP residual solids sewer discharge did not negatively impact treatment processes at the SEWWTP and is sustainable.

Thesis (MEng (Civil Engineering))--Cape Peninsula University of Technology, 2019
The textile industry is considered one of the most polluting sectors in terms of the large volume and toxic composition of the effluent that is generated. For example, the effluent contains dyes, which represent an environmental hazard when discharged without proper treatment. This study aimed to assess the use of recycled alum sludge (RAS) as an alternative treatment for the reduction of colour from dye based synthetic textile industry wastewater. To determine treatment efficiency, the colour, chemical oxygen demand (COD), total dissolved solids (TDS), and pH before and after treatment were monitored. The pH at which optimal removal rates were achieved was also determined. Coagulation/flocculation experiments were conducted on five batches of synthetic wastewater containing disperse dye with an average colour, COD and TDS of 133 ± 13 mg/l (range 115-145 mg/l), 38 ± 4 mg/l (range 32-43 mg/l) and 779 ± 18 mg/l (range 754-804 mg/l), respectively, using a coagulant of alum:RAS mixed in ratios of 1:0, 0:1. 1:1, and 1:2. An average removal efficiency of 89 ± 2% (range: 81-96%) for colour, 29 ± 3% (range: 19-41%) for COD, and 36 ± 4% (range 19-59%) of TDS was recorded during treatment with fresh alum (unmixed). The average removal efficiencies for treatment with RAS (ratio 1:0, i.e. unmixed) were 78 ± 3% (range 67-88%), 22 ± 3% (range 14-34%) and 32 ± 1% (range 29-35%) for colour, COD and TDS, respectively. When fresh alum sludge was mixed with RAS at a ratio of 1:1, average colour and TDS removal efficiencies of 86 ± 3% (range 83-88%), 37 ± 5% (range 30-50%), respectively were achieved, while at ratios of 1:2, the average colour and TDS removal efficiencies were 82 ± 2% (range: 80-84%) and 30 ± 5% (range 22-35%), respectively. Increases in the COD concentrations were observed when fresh alum sludge was mixed with RAS in 1:1 and 1:2 ratios. However, the initial COD concentrations in the synthetic wastewater were low [38 ± 4 mg/l (range 32-43 mg/l)] and increases after treatment were marginal (3 ± 7% and 9 ± 3%, respectively). A second method was applied for colour removal from the synthetic wastewater, namely adsorption with corn cobs. Results were inconclusive due to high levels of turbidity in the treated effluent caused by leaching of components from the shredded corn cobs. This study intended to present alternative means or methods for the treatment of textile wastewater containing dye. The findings of this study compared well with previous laboratory studies conducted with synthetic textile wastewater containing dye. The coagulant of fresh alum and RAS mix ratio of 1:1 offered the best alternative to fresh alum in the treatment of synthetic textile wastewater in terms of reduction of disperse dye from the synthetic textile wastewater. The use of RAS could reduce the volume of waste to be discarded as well as the amount of fresh coagulant necessary for the daily operation.

Nitrogen and phosphorus removal is often required before discharge of treated wastewater to sensitive water bodies. Kayseri Wastewater Treatment Plant (KWWTP) is a biological wastewater treatment plant that includes nitrogen and phosphorus removal along with carbon removal. The KWWTP receives both municipal wastewater and industrial wastewaters. In this study, KWWTP was modeled by using a software called GPS-X, which is developed for modeling municipal and industrial wastewaters. The Activated Sludge Model No.2d (ASM2d) developed by the International Association on Water Quality (IAWQ) was used for the simulation of the treatment plant. In this model, carbon oxidation, nitrification, denitrification and biological phosphorus removal are simulated at the same time. During the calibration of the model, initially, sensitivities of the model parameters were analyzed. After sensitivity analysis, dynamic parameter estimation (DPE) was carried out for the optimization of the sensitive parameters. Real plant data obtained from KWWTP were used for DPE. The calibrated model was validated by using different sets of data taken from various seasons after necessary temperature adjustments made on the model. Considerably good fits were obtained for removal of chemical oxygen demand (COD), total suspended solids (TSS) and nitrogen related compounds. However, the results for phosphorus removal were not satisfactory, probably due to lack of information on volatile fatty acids concentration and alkalinity of the influent wastewater.

The effects of in-basin storage of sludge on the iron, manganese, and TOC removal of water treatment plant (WTP) clarifiers and on the dewatering characteristics of sludge were examined. The use of chlorine dioxide as a preoxidant to retard observed detrimental effects was also investigated.

Sludge samples that were stored over a period of 120 days were found to release up to ten times the original supernatant concentration of iron and manganese from the sludge into the overlying supernatant liquor when sludge redox potential values decreased below +100 mV. Organic carbon also increased in the supernatant but to a lesser extent. Sludge dewatering characteristics as measured by specific resistance and capillary suction time were found to improve when sludge redox potential readings remained over 100 mV but varied greatly when readings were below this level.

Field monitoring and sampling of the clarifiers at Lee Hall WTP and Harwood's Mill WTP from April to July showed that the removal efficiencies of the clarifiers was not related to in-basin sludge storage. This conflicted with a later portion of the study and was thought to be due to the lack of standardized sampling techniques.

The final phase of the investigation dealt with the use of chlorine dioxide to retard the negative effects of in-basin storage of sludge. Sludge accumulation in clarifiers resulted in decreased iron and manganese removal efficiencies when chlorine dioxide was not used. Addition of chlorine dioxide improved the iron and manganese removal efficiencies of the clarifiers. Sludge dewatering characteristics were found to improve with the use of chlorine dioxide as a preoxidant.

Master of Science

This master thesis gives an account for various aeration schemes that are utilized in conventional activated sludge treatment process in a wastewater treatment plant. By altering between different aeration schemes, the project aimed at reducing energy consumption along with maintaining the treatment performance at the plant. A series of experiments on the treatment performance over several different aeration schemes thus has been conducted on site at Solviken in Mora, Sweden. The project is basically a case study where no parameters were manually controlled except for the aeration schemes at the plant. Energy consumption reduction is logically relative to the ratio between aeration and non-aeration intervals. Several criteria were tested in regards to the treatment performance, including pH value, organic matters, phosphorus substances and microorganisms. The study has come up with a superior aeration scheme for the plant, as well as indicated processes that can be improved at the plant.

Thesis (MSc Food Sc)--Stellenbosch University, 2004.
ENGLISH ABSTRACT: The wine industry significantly contributes to South Africa's water demand and subsequent pollution of the limited resource. Wastewater is produced throughout the year with an increase in volume and organic load during the vintage season. Anaerobic digestion (AD), specifically the upflow anaerobic sludge bed (UASB) technology has been shown to be feasible in the treatment of cellar wastewater. However, the legal standard for chemical oxygen demand (COD) for disposal in a natural water resource (75 rnq.L") is often not met. The aim of the study was to conduct a laboratory-scale investigation into the feasibility of combining pre- and post-ozonation processes with AD in order to achieve a final COD closer to the legal disposal limit. While acclimatising an UASB bioreactor containing mixed anaerobic granules to a cellar wastewater with a pH set at 8.0, stable-state conditions were not reached. Sucrose additions to the substrate, increased substrate loads, heattreatment of the substrate and an addition of isolated cellar effluent bacteria to facilitate degradation prior to AD, were all unsuccessful in maintaining stable-state in terms of COD removal efficiency. Once the substrate pH was re-set to 7.5, the reactor stabilised. The lowest efficient operational pH was found to be 5.73 resulting in a COD removal of 88% at a substrate COD < 5 000 rnq.L". At a substrate pH of 6.0, the lowest efficient operational hydraulic retention time (HRT) and corresponding organic loading rate (OLR) were 19.7 hand 9.75 kg COD.m-3d-1 , respectively, with the COD removal being maintained around 84%. The reactor effluent still had a final COD of 1280 rnq.L", which was well above the legal South African limit. Dominant bacteria were isolated from raw cellar wastewater and identified as Acinetobacter haemolyticus, Burkholderia cepacia and Cryseomonas luteola. In order to investigate the possibility that ozonation improved biodegradability, the growth of the isolates at 35°C was monitored over 24 h in sterile ozonated and non-ozonated substrates from the vintage and non-vintage seasons. All the isolates increased by at least 1.5 log cycles in the control substrates from both seasons. Ozonation of the wastewater batches for 10 min at a rate of 73 rnq.L" led to slightly increased growth of the inoculants in the substrate batch from the vintage season. For the substrates from the non-vintage season, ozonation had an inhibitory effect on the bacterial growth. A 5 min ozonation treatment at a concentration of 73 rnq.L" was found to be optimal for both a pre- and post-treatment to UASB-treatment of cellar wastewater. Both UASB treatment and ozonation were effective in reducing the COD by 85% and 20%, respectively. The COD reduction was improved to 88% when UASB treatment was combined with post-ozonation. The total reduction in total suspended solids (TSS) for the combined process was 97%, compared to 80% for UASB and 73% for an ozone treatment alone. The reduction for volatile suspended solids (VSS) was 98% compared to 81% for UASB and 73% for the ozone treatment alone. The total reduction when using a pre-ozonation UASB treatment combination was an average of 86% for COD. The TSS and VSS were both reduced by 95%. Biogas production increased from 1.4 L.d-1 to 3.8 L.d-1 when an ozonated wastewater was used as substrate. When the UASB treatment was combined with both a pre- and post-ozonation treatment process, the COD was reduced by 89% while TSS and VSS were both reduced by 99%. This study showed that pre- and post-ozonation treatment processes could successfully be utilised to improve UASB treatment of cellar wastewater. Although the legal limits for discarding into a natural resource were not met, significant progress was made in reducing COD levels. Cellar wastewaters do however, vary according to season and the wastewater composition could affect the efficiency of a pre-ozonation process.
AFRIKAANSE OPSOMMING: Die wynindustrie maak "n beduidende bydrae tot die eise wat aan Suid-Afrika se waterbronne gestel word en gevolglik die besoedeling van die beperkte hulpbron. Afloopwater, wat in volume en organiese lading gedurende die parstyd toeneem, word reg deur die jaar opgelewer. Anaërobiese vertering (AV), spesifiek die "Upflow anaerobic sludge blanket" (UASB) tegnologie, is alreeds suksesvol gebruik om kelderafloop te behandel. Die wetlike vereiste vir chemiese suurstof behoefte (CSB) vir storting in "n natuurlike hulpbron (75 rnq.L"), word egter dikwels nie bereik nie. Die doel van die studie was om in "n laboratorium-skaal ondersoek AV te kombineer met voor- en na-osoneringsprossesse, om sodoende te poog om "n CSB nader aan die wetlike standaard te verkry. Terwyl"n UASB bioreaktor wat gemengde anaerobiese granules bevat het, geakklimatiseer is tot kelderafloop met "n pH gestel tot 8.0, kon stabiele toestande nie bereik word nie. Die byvoeging van sukrose tot die substraat, verhoogde substraatladings, hitte-behandeling van die substraat en die byvoeging van geïsoleerde kelderafloop bakterië om substraatafbraak voor AV aan te help, was onsuksesvol om stabiliteit in terme van CSB-verwydering, te handhaaf. "n Verstelling van die substraat pH na 7.5, het gelei tot reaktorstabiliteit. By die laagste doeltreffende bedryfs-pH van 5.73 en substraat CSB < 5 000 rnq.L", was die CSB-verwydering 88%. By "n substraat pH van 6.0 was die laagste doeltreffende bedryfs-hidroliese retensie tyd en -organiese ladingstempo 19.7 h en 9.75 kg CSB.m-3d-1, onderskeidelik, terwyl die CSB verwydering rondom 84% gehandhaaf is. Die CSB van die reaktoruitvloesel van 1 280 rnq.L", was steeds ver bo die wetlike vereiste. Dominante bakterië is uit kelderafloop geïsoleer en as Acinetobacter haemolyticus, Burkholderia cepacia en Cryseomonas luteola, geïdentifiseer. Die moontlikheid dat osonering bioafbreekbaarheid bevorder, is ondersoek deur die groei van die isolate by 35°C oor 24 h in steriele geësoneerde en ongeësoneerde substrate te monitor. Die substrate is berei vanaf kelderafloop wat in die parsseisoen sowel as die nie-parsseisoen versamel is. AI die isolate het met ten minste 1.5 log siklusse in die kontrole substrate van beide seisoene, vermeerder. Vir die kelderafloop wat in die parsseisoen versamel is, het osonering vir 10 min teen 73 rnq.L" gelei tot effens verbeterde groei van die innokulante. Osonering het 'n onderdrukkende effek op die groei van bakterië in die afloopwater versamel in die nie-parsseisoen, gehad. Osonering vir 5 min teen 'n konsentrasie van 73 rnq.L" is as optimum vir beide voor- en na-osoneringsbehandeling tot UASB-behandeling van die kelderafloop, gevind. UASB-behandeling en osonering het die CSB met 85 en 20% onderskeidelik, verminder. Die vermindering kon tot 88% verhoog word wanneer UASB-behandeling met na-osonering gekombineer is. Die vermindering in totale gesuspendeerde vastestowwe (TGV) vir die gekombineerde proses was 97%, in vergelyking met 80% vir UASB- en 73% vir osoonbehandeling alleen. Die vermindering in vlugtige gesuspendeerde vastestowwe (VGV) was 98% in vergelyking met 81% vir UASB- en 73% vir osoonbehandeling alleen. Die totale CSB verwydering vir 'n voor-osonerings UASB kombinasie was gemiddeld 86%. Die TGV en VGV is beide met 95% verminder. Biogasproduksie het ook vermeerder vanaf 1.4 L.d-1 tot 3.8 L.d-1 toe geosoneerde afloopwater as substraat gebruik is. Die kombinasie van UASB-behandeling met voor-osonering, sowel as na-osonering het gelei tot 'n CSB-verwydering van 89% terwyl TGV en VGV beide met 99% verminder is. Hierdie studie het getoon dat voor- en na-osonering suksesvol gebruik kan word om UASB-behandeling van kelderafloop te verbeter. Hoewel wetlike vereistes vir storting in 'n natuurlike hulpbron nie bereik is nie, is beduidende vordering gemaak in die verlaging van CSB-vlakke. Die verskil in die samestelling van kelderafloop gedurende die onderskeie seisoene, kan egter die doeltreffendheid van die voor-osoneringsproses beïnvloed.

Possibilities for energy recovery from sludge at Chişinȃu wastewater treatment plant have been investigated and evaluated. One way of recovering energy from sludge is to produce biogas through anaerobic digestion. Which method of biogas usage that is to prefer in Chişinȃu has been evaluated from a cost-efficiency point of view. There is a possibility that a new waste incineration plant will be built next to the wastewater treatment plant, and therefore solutions that benefit from a co-operation have been discussed. The results show that biogas production would be suitable and profitable in a long time perspective if the gas is used for combined heat and power production. Though, the rather high, economical interest rates in Moldova are an obstacle for profitability.

The provision of clean drinking water typically involves treatment processes to remove contaminants. The conventional process involves coagulation with hydrolysing metal salts, typically of aluminium (‘alum’) or trivalent iron (‘ferric’). Along with the product water this also produces a waste by-product, or sludge. The fact of increasing sludge production — due to higher levels of treatment and greater volume of water supply — conflicts with modern demands for environmental best practice, leading to higher financial costs. A further issue is the significant quantity of water that is held up in the sludge, and wasted.
One means of dealing with these problems is to dewater the sludge further. This reduces the volume of waste to be disposed of. The consistency is also improved (e.g. for the purpose of landfilling). And a significant amount of water can be recovered. The efficiency, and efficacy, of this process depends on the dewaterability of the sludge.In fact, good dewaterability is vital to the operation of conventional drinking water treatment plants (WTP’s). The usual process of separating the particulates, formed from a blend of contaminants and coagulated precipitate, relies on ‘clarification’ and ‘thickening’, which are essentially settling operations of solid–liquid separation.WTP operators — and researchers — do attempt to measure sludge dewaterability, but usually rely on empirical characterisation techniques that do not tell the full story and can even mislead. Understanding of the physical and chemical nature of the sludge is also surprisingly rudimentary, considering the long history of these processes.
The present work begins by reviewing the current state of knowledge on raw water and sludge composition, with special focus on solid aluminium and iron phases and on fractal aggregate structure. Next the theory of dewatering is examined, with the adopted phenomenological theory contrasted with empirical techniques and other theories.The foundation for subsequent analyses is laid by experimental work which establishes the solid phase density of WTP sludges. Additionally, alum sludges are found to contain pseudoböhmite, while 2-line ferrihydrite and goethite are identified in ferric sludges.
A key hypothesis is that dewaterability is partly determined by the treatment conditions. To investigate this, numerous WTP sludges were studied that had been generated under diverse conditions: some plant samples were obtained, and the remainder were generated in the laboratory (results were consistent). Dewaterability was characterised for each sludge in concentration ranges relevant to settling, centrifugation and filtration using models developed by LANDMAN and WHITE inter alia; it is expressed in terms of both equilibrium and kinetic parameters, py(φ) and R(φ) respectively.This work confirmed that dewaterability is significantly influenced by treatment conditions.The strongest correlations were observed when varying coagulation pH and coagulant dose. At high doses precipitated coagulant controls the sludge behaviour, and dewaterability is poor. Dewaterability deteriorates as pH is increased for high-dose alum sludges; other sludges are less sensitive to pH. These findings can be linked to the faster coagulation dynamics prevailing at high coagulant and alkali dose.Alum and ferric sludges in general had comparable dewaterabilities, and the characteristics of a magnesium sludge were similar too.Small effects on dewaterability were observed in response to variations in raw water organic content and shearing. Polymer flocculation and conditioning appeared mainly to affect dewaterability at low sludge concentrations. Ageing did not produce clear changes in dewaterability.Dense, compact particles are known to dewater better than ‘fluffy’ aggregates or flocs usually encountered in drinking water treatment. This explains the superior dewaterability of a sludge containing powdered activated carbon (PAC). Even greater improvements were observed following a cycle of sludge freezing and thawing for a wide range of WTP sludges.
Further aspects considered in the present work include deviations from simplifying assumptions that are usually made. Specifically: investigation of long-time dewatering behaviour, wall effects, non-isotropic stresses, and reversibility of dewatering (or ‘elasticity’).Several other results and conclusions, of both theoretical and experimental nature, are presented on topics of subsidiary or peripheral interest that are nonetheless important for establishing a reliable basis for research in this area.
This work has proposed links between industrial drinking water coagulation conditions, sludge dewaterability from settling to filtration, and the microstructure of the aggregates making up that sludge. This information can be used when considering the operation or design of a WTP in order to optimise sludge dewaterability, within the constraints of producing drinking water of acceptable quality.

This thesis describes the development of enhanced biological phosphorus removal (EBPR) in a lab-scale sequencing batch reactor (SBR) and the release of phosphorus during the storage and thickening of sludge produced in this reactor. In the first phase of the experimental work a fast start-up method for EBPR development was established by the addition of a pure culture of Acinetobacter lwoffi to a conventional activated sludge. Investigations revealed that the performance EBPR depended on the combination of influent COD and phosphorus values and that in the investigated range, EBPR functioned independently of the sludge retention time. Low dissolved oxygen levels had no effect on the phosphorus removal properties of the sludge. The second phase of the experimental work involved the investigation of the phosphorus released during sludge handling. It was found that phosphorus resolubilisation during sludge treatment took place in three distinct phases which included an initial period of extremely low phosphorus release. Alterations of the reactor influent and operational parameters and the sludge characteristics, affected the amount of phosphorus released during anaerobic storage and gravity thickening. It was found that for short retention times in the sludge processing units (1-48 hours), decreasing the influent phosphorus concentration, increasing the oxidised nitrogen content of the excess sludge and wasting the excess sludge from the aeration tank decreased the amount of phosphorus resolubilised. For longer retention times (2-7 days), it was found that increasing the influent COD, having a lower total phosphorus sludge content, higher sludge "stabilisation" rates and quiescent conditions of storage, decreased the amount of phosphorus released.

Rheological behaviour of sludge is a function of various operational parameters. This research is aimed at investigating rheological characteristics of sludge from different sections of a wastewater treatment plant under the influence of varying operational parameters and determining experimentally the optimum operating conditions. It also involved the development of predictive rheological model based on historical data so that rheology can be used as a tool for the monitoring, control, and optimization of dewatering process.

Duvbacken wastewater treatment plant in Gävle, Sweden, currently designed for 100,000 person equivalent (P.E.) is looking for a new permit for 120,000 P.E. due to the expected increase of the population in the community. Moreover, the recipient of the plant’s effluent water was characterized as eutrophic in 2009. The plant emissions are regulated regarding seven days biological oxygen demand (BOD7) and total phosphorus (Ptot) emissions. Yet, there is no available computer model to simulate the plant operations and investigate the emissions of the requested permit. However, it was uncertain if the available data would be sufficient for the development of a new model. A model of the plant was eventually developed in BioWin® software under a number of assumptions and simplifications. A sensitivity analysis was conducted and used conversely than in other studies. The sensitivity analysis was conducted for the uncalibrated model in order to indicate its sensitive parameters. The parameters of substrate half saturation constant for ordinary heterotrophic organisms (KS) and phosphorus/acetate release ratio for polyphosphate accumulating organisms (YP/acetic) were finally used for model calibration. Following, the model validation confirmed the correctness of the calibrated model and the ability to develop a basic model under data deficiency. The new model was used to investigate a loading scenario corresponding to 120,000 P.E. where plant emissions that meet the current permits were predicted. Some suggestions proposed were the installation of disc filters in order to further reduce the effluent phosphorus and BOD precipitation in cases of high influent concentrations. In case of the application of a nitrogen (N) permit, the installation of membrane bioreactors and a full-scale chemical P removal was proposed as an alternative that will require a smaller footprint expansion of the plant.

För att simulera aktivslamprocessen på ett reningsverk krävs en dynamisk modell som realistiskt beskriver processen. 1987 kom IWA, International Water Association med ASM1, Activated Sludge model no. 1 som fortfarande är den mest använda modellen för att beskriva denna process. I detta examensarbete har ASM1 används för att beskriva aktivslamprocessen på Henriksdals reningsverk i Stockholm. Arbetet har utförts som en del i ett europeiskt projekt, HIPCON (Holistic Integrated Process CONtrol) på IVL, Svenska Miljöinstitutet AB.

Arbetet har gått ut på att ta fram en modell som realistiskt beskriver aktivslamprocessen och eftersedimenteringen. För att göra detta har en referensmodell i MATLAB/Simulink använts som grund och byggts om för att likna processen vid Henriksdal. Denna modell i Simulink använder ASM1 för att beskriva aktivslamprocessen. Eftersedimenteringen modelleras med en massbalansmodell där sedimenteringshastigheten beskrivs av en dubbelexponentiell sedimenteringsfunktion. Både ASM1 och sedimenteringsfunktionen använder en mängd olika parametrar för att beskriva processerna och dessa måste kalibreras fram för den process som skall modelleras. Aktivslamprocessen är en biologisk process som beror på en mängd yttre och inre faktorer och är unik för varje reningsverk. Därför finns det inte något enkelt sätt att kalibrera en modell på och information för det enskilda reningsverket i fråga måste tas fram. I detta arbete har två mätkampanjer utförts på Henriksdal för att få mätserier till kalibrering och validering samt information om avloppsvattnets sammansättning. Litteraturstudier har också genomförts för att få information om vilka parametervärden som är av störst intresse för modellen samt i vilket område varje parameter kan förväntas finnas.

Arbetet har sedan gått ut på att efter riktlinjer för kalibrering funna i litteraturen ta fram en modell som så realistiskt som möjligt beskriver processen på Henriksdal. Först genomfördes en kalibrering med medelvärden för att hitta jämviktstillstånd och därmed en stabil modell på länge sikt. Utifrån den modellen utfördes sedan en dynamisk kalibrering för att få en modell som beskriver även kortsiktiga och snabba förändringar. Till sist utfördes en validering för att kontrollera om modellen fungerar även för en dataserie som ej använts vid kalibrering. Den framtagna modellen fungerade mycket bra för att modellera medelvärden på lång sikt. För snabba förändringar verkade modellen ligga fel i tiden och troligtvis var den reella uppehållstiden kortare än den teoretiska och bidrar till sämre modellanpassning.

To simulate the activated sludge process at a wastewater treatment plant a dynamic model that describes the process is needed. In 1987 IWA, International Water Association presented ASM1, Activated Sludge Model No.1 which still is the most widely used model for this process. In this thesis the ASM1 has been used to describe the activated sludge process. The work is a part of a European project, HIPCON (Holistic Integrated Process CONtrol) at IVL, Swedish Environmental Research Institute.

The main objective of the work was to calibrate a model that realistically describes the activated sludge process and secondary sedimentation at Henriksdal wastewater treatment plant in Stockholm. A benchmark model in MATLAB/Simulink was used as a base and rebuilt and extended to fit the process of Henriksdal. In the model ASM1 is used to describe the activated sludge process. The settler is modelled with a mass balance model where the settling velocity is described by a double exponential function. The parameters used in both models have to be calibrated to fit the wastewater treatment plant. To find information about Henriksdal two measuring campaigns were performed to provide data for calibration and validation and to gather information about the composition of the incoming wastewater. From this data a model was developed and calibrated for the process at Henriksdal. After calibration the obtained model worked very well for modelling average values but did not adjust quite as well to fast dynamic changes.

This experimental investigation was started to study the impacts urine separated WW [Wastewater] can have on BNRAS WWTPs [Biological Nutrient Removal Activated Sludge Wastewater Treatment Plants] with a UCT and a JHB configuration.

In the last years, the role of wastewater treatment plants has become even more relevant not only as final destination of the collected sewage but also as a center of the sustainable approaches for the water cycle. Moreover, the considerable improvements in wastewater treatment control technologies enable now the implementation of advanced sustainable management perspectives. A particular incentive to increase the efficiency of WWTPs performances comes from the possibility to reuse treated wastewater. In this context, the overall aim of this PhD thesis was to investigate the implementation of models in the most relevant sections of pilot and full-scale plants, and to study the possibility on reusing treated wastewater coming from the effluent flow rate of existing plants for irrigation purpose. We have implemented the WEST 2012 modeling software that allows different control policies using data acquired on a pilot plant located in Trebbo di Reno (Italy). These simulations have evidenced the real possibility to manage small-scale plants with automatic controller while respecting the legal limits for discharge. We have also studied the finishing effect of the natural treatment phase using data recorded during several monitoring campaigns on the Santerno full-scale plant located in Imola (Italy). The removal efficiency resulting from the monitoring campaigns reaches 40% for Ammonium and 20% for Total Nitrogen. The disinfection capacity, E. coli removal efficiency up to 40%, does not permit irrigation reuse so appropriate management policies are necessary. In addition, a pilot plant has been designed and implemented in the Santerno area and the first monitoring data show a real possibility to test management policies first in the pilot-plant and then on full scale plant. Finally, we observed that organic chemicals in wastewater treatment plant have a low biodegradability and can be drastically accumulated during irrigation, which represents a critical issue in the future.

Microplastics (i.e., plastics particles < 5mm) are widespread emerging contaminants that have been detected in various aquatic environments worldwide including freshwater and marine ecosystems. Contamination of the environment with microplastics has become an environmental issue due to the potential of plastics to remain for thousands of years and to accumulate in the aquatic environment. The abundance of microplastics in the aquatic environment is assumed to increase due to continuous fragmentation of macro and microplastic debris, which can lead to a decrease in the average size ranges of microplastics over time (Cole et al., 2011). Moreover, concerns have been raised regarding the potential of microplastics to physically (e.g., blockage of digestive tract) and chemically (e.g., leaching of sorbed chemicals and toxic additives) harm aquatic organisms. Microplastics can enter the aquatic environment from both aquatic-based and landbased sources. Recently, wastewater treatment plants (WWTP) have been identified as one of the important land-based sources of microplastics. While microplastics have been reported in WWTP effluent in Asia, Europe, USA and Russia, little is known about the presence of microplastics in Australian WWTP effluent. More importantly, the lack of standardized techniques to sample and characterize microplastics in environmental samples, especially in complex samples such as wastewater, has led to inaccurate estimations of microplastic concentrations. In response to the current knowledge gaps, a novel validated high-volume sampling device was developed for in situ fractionation of microplastics from wastewater effluent as part of this project. The developed method was applied to three Australian WWTPs utilizing primary, secondary and tertiary treatments to provide a snapshot of the fate and removal of microplastics during various wastewater treatment processes. To achieve an accurate estimation of microplastics, the sampling technique was combined with an efficient sample processing method. Microplastic polymer type, shape and potential origin were further determined using microscopy analysis and Fourier Transform Infrared (FTIR) spectroscopy. The efficiency of the sampling device was found to be between 92 to 99% for 500 and 25 μm mesh screens. The results showed that the concentrations of microplastics were 1.5, 0.6 and 0.2 microplastics per liter of effluent in primary, secondary and tertiary effluent, respectively. It was also found that the majority of detected microplastics in the studied WWTPs were polyethylene terephthalate (PET) fibers, which is assumed to originate from synthetic clothing. Polyethylene (PE) beads and fragments, which may be associated with cosmetic products, were the second most frequently detected type of microplastic. Despite a thorough sample processing method, FTIR spectroscopy revealed that between 22 to 90% of the suspected microplastic particles were in fact non-plastic particles. This study suggests that WWTPs can act as a significant source of microplastics to the aquatic environment given the large volume of wastewater discharged to the aquatic environment. To date, the effects of microplastics on aquatic organisms have mostly been examined using high and often unrealistic concentrations of microplastics (e.g., milligram per liter range). Moreover, while the presence of different types of microplastics together in aquatic ecosystems has been widely reported, the potential effects of microplastics when they occur as mixtures are largely unknown. To cover these knowledge gaps, the potential adverse effects of wastewater-based microplastics (such as fibers and beads) at lower concentrations on the freshwater organism Ceriodaphnia dubia were evaluated. The acute (48 h) and chronic (192 h) effects of PET fibers and PE bead microplastics on C. dubia were assessed alone and as a binary mixture. The results showed a dose-dependent trend on survival, with C. dubia more sensitive to PET fibers than PE microplastics. The 48 h EC50 value of fibers was 1.5 mg/L compared to 2.2 mg/L for PE beads. The binary mixture of microplastic beads and fibers demonstrated less than additive effects. EC50 values for the chronic bioassay were 429 μg/L for fibers and 958 μg/L for PE microplastics. A positive trend of decreasing growth (body size of adults) and reproduction rate (number of neonates) with increasing microplastic concentration was observed for both PE and fiber microplastics during the chronic bioassays. Using scanning electron microscopy (SEM) we observed deformities, such as carapace and antenna deformation, in C. dubia exposed to fibers at a high concentration, but not at the lower (environmentally relevant) concentrations. Given the likelihood that microplastics will eventually sink to the bottom sediment in the aquatic ecosystem the effects of microplastics were investigated on a freshwater sediment-dwelling organism (Chironomus tepperi) at environmentally relevant concentrations of PE microplastics (500 particles/kgsediment). Possible size-dependent effects of microplastics were also examined using four different size ranges of PE beads including 1-4, 10-27, 43-54 and 100-126 μm. The results revealed that exposure to an environmentally relevant concentration of microplastics had a detrimental impact on the survival, growth (i.e., body length and head capsule) and emergence of C. tepperi. The observed effects were strongly dependent on microplastic size with C. tepperi more sensitive to microplastics in the size range of 10-27 μm. No negative effects were observed on growth and survival of C. tepperi exposed to the larger microplastics (100-126 μm), though a significant decrease in the number of emerging adults was observed in the organisms exposed to the same size range of microplastics. Further, SEM showed a significant reduction in the size of the head capsule and antenna in C. tepperi exposed to microplastics in the size range of 10-27 μm. These results showed that environmentally relevant concentrations of microplastics in sediment can result in adverse effects on the development and emergence of C. tepperi, with effects strongly dependent on particle size. Finally, we evaluated the effects of PE microplastics on the acute toxicity of a pyrethroid insecticide (bifenthrin) to midge larvae (C. tepperi) in water. To test the single and combined effects of bifenthrin and PE microplastics, C. tepperi larvae were exposed to six concentrations of bifenthrin ranging from 0.1 to 3.2 μg/L in the presence and absence of microplastics. To examine the possible effects of bifenthrin and microplastics in synthetic and real water, the bioassays were performed in both moderately hard water (MHW) and river water. We performed an uptake study using three different size ranges of microplastics (10-27, 43-54, 100-126 μm) during 8-day microplastics-spiked water exposure. The results showed that microplastics in the size range of 10-27 μm were mostly ingested by C. tepperi larvae. Using this finding, 10-27 μm microplastics were selected for the bioassays. The results of the bioassays using MHW demonstrated a significant decrease in the toxicity of bifenthrin in the presence of microplastics. This is likely attributable to the tendency of bifenthrin to bind to the microplastics, which reduces the bioavailability of bifenthrin to midge larvae. However, in the bioassays conducted in river water with a total organic carbon (TOC) concentration of 9.6 mg/L, no significant difference was observed between the toxicity of bifenthrin to C. tepperi in the presence and absence of microplastics. This is likely due to the interaction between organic carbon and bifenthrin, which reduces the bioavailability of bifenthrin to C. tepperi larvae. This thesis highlights that microplastic fibers and beads are released to the aquatic environment from WWTPs, and that this can negatively affect survival, reproduction and the life cycle of aquatic organisms (both pelagic and benthic) through entanglement (fibers) and ingestion (beads). The effect of microplastics on chemical contaminants is complex, and microplastics may act both as carriers but also as “chelators” of chemicals in the water, thereby reducing their bioavailability.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Environment and Sc
Science, Environment, Engineering and Technology
Full Text

Due to a combination of selection criteria, sludges from upflow anaerobic digesters treating industrial waste waters consist primarily of well-settling, dense agglomerates called granules. Quantification of the component mixed microbial populations of these granules has been severely restricted by the inability of researchers to disrupt them without concomitantly destroying numerous cells. In situ quantification using light and electron microscopy is complicated by the high cell numbers and bacterial diversity; the small cell size; and the destructive nature of electron microscopy preparative techniques preventing the viewing of more than a small percentage of the population at a time. For these reasons, in this investigation, standardization of qualitative electron microscopic techniques was performed prior to their application to granules. Isolation and electron and light microscopic techniques were applied to granules from a fullscale clarigester treating effluent from a maize-processing factory. In addition, a method using montaged transmission electron micrographs (TEMs) taken along a granule radius, and image analysis, was developed for bacterial quantification within granules. This method, together with antibody probe quantification, was applied to granules from an upflow anaerobic sludge blanket (UASB) digester treating a brewery effluent. The clarigester granules contained a metabolically and morphologically diverse population of which many members were not isolated or identified. By contrast, the UASB digester granules consisted primarily of morphotypes resembling Methanothrix, Methanobacterium and Desulfobulbus, in order of predominance. However, only about one-third of the population reacted with antibody probes specific to strains of bacterial species expected to occur within these granules. According to the antibody probe library used, the Methanobacterium-like cells observed in TEMs were probably Methanobrevibacter arboriphilus. From this study it is apparent that different anaerobic digester designs, operational parameters, and the chemical composition of the waste water purified, are factors which influence the formation and maintenance of granules differing with respect to their microbial populations. Until the difficulties associated with quantification are overcome, the processes governing granule formation and/or population selection will remain obscure.
Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 1995.

The enormous rate of increase in waste generation across the world is a serious threat to the future generation, if not handled properly, due to the creation of health hazards and global warming. This was awakened many engineers and researchers to find an appropriate solution for efficient management of waste. The land filling of the waste is the most widely adopted method for its disposal, whose efficiency mainly depends on the engineered barrier system in place. Though possessing many limitations, clay liner solely or along with Geo-membrane is often used to avoid ground and surface water contamination. The thickness of the liner of a given breakthrough time depends on the transport rates of the selected contaminants. To estimate the transport rate of any given contaminant, it is necessary to understand the different migration processes of contaminants through the liner material. It was observed from the literature that, the transport rate of contaminants mainly depends on Dispersion coefficient (D) and Distribution coefficient (K) which are the main contaminant transport parameters. The amount of contaminant transport through the liner system for a desired time period is thus estimated from these contaminant transport parameters using the Advection-Dispersion Equation (ADE). The unregulated open dumps are another cause of serious environmental problem, where the contaminants are free to migrate in any direction through the underground soil. The percolation rate and the accumulation of leachate increase during the rainy season, which picks up more contaminants from the waste and thus the threat of the leachate increases. The leachate normally migrates in vertical and lateral directions, causing contamination of ground and surface water resources, and hence, there is a need to estimate the transport rates of contaminants in the porous media. These transport rates are not only useful for designing barrier systems, but also useful to find a suitable remediation technique for the removal of contaminants from a contaminated site. Thus, determination of transport rate is very important in effective waste management systems. Most of the researchers have obtained the contaminant transport parameters through the column tests to simulate one dimensional flow. Often, it is a lengthy process and there is a need to find an easy and effective method of determining these parameters which can reduce the time and effort. Generally, the metallic contaminants such as Cadmium (Cd), Copper (Cu), Lead (Pb), Mercury (Hg), Nickel (Ni) and Zinc (Zn) which are most hazardous are considered for the contaminant migration studies. In the present study, the transport rates of two heavy metals Copper and Zinc through locally available Black Cotton soil and Red soil were studied. Column experiments were conducted to simulate the field conditions under two types of test conditions i.e., Constant and Decreasing source concentrations. For Black Cotton soil as the hydraulic conductivity was very less and was taking a long time for achieving complete breakthrough, the soil sectioning method was used to get the depth versus concentration. The soil sectioning method involves the determination of pore water concentration of any given contaminant in different sections of the soil column. The depth versus concentration profile can serve as the same purpose as that of complete column test after breakthrough. The column experiments can be done only up to a relative concentration (C/C0) of about 0.2 instead of 0.8 or more. The soil samples were compacted to different densities to know the effect of density on transport parameters. The Black Cotton Soil samples were compacted to 0.76-0.97 times of maximum dry density and Red Soil samples were compacted to 0.81-0.98 times of maximum dry density. The samples were compacted to lesser densities to reduce the experimentation time. The transport parameters for field densities can be determined by setting „Forecast Trend Lines‟ to the density versus dispersion coefficient and density versus distribution coefficient plots. The contaminant transport was modeled by various methods i.e., Analytical, Semi-analytical, Explicit Finite Difference and Implicit Finite Difference methods. These models can be extended to predict the contaminant migration through soil liners constructed with similar soils. During the lifetime of a landfill, it may be subjected to both constant and decreasing source concentration conditions and thus the contaminant transport parameters determined by both constant and decreasing tests will be useful to estimate the optimum thickness of soil liner. The disposal of waste solutions and sludges by industries has led to problems with the contamination of both soil and groundwater. Much research work has not been carried out in the past for the remediation of contaminated soils in India. Thus an attempt has been made to study in detail the different remediation techniques on various contaminated soils. Three heavy metal contaminated soils were studied with two remediation techniques i.e., Soil washing and immobilization. As a case study, Zinc contaminated soil was collected from Hindustan Zinc Limited located near Udaipur in Rajasthan State, India and column leach tests were conducted on this soil with different leaching solutions to study the efficiency of the soil washing technique. The leaching solutions used for removing zinc from this soil were 0.1N HCl, 0.1N EDTA, 0.1N HCl+0.1N EDTA and 0.1N FeCl3. It was found that 0.1N FeCl3 was more efficient to remove zinc from this soil. The removal efficiency was also high with 0.1N HCl+0.1N EDTA solution. The transport rates were determined by matching the theoretical elution curves with experimental elution curves. The contaminant transport for column leach tests was modeled using analytical solution based on the Leaching Mass Ratio approach. These transport rates are useful to estimate the rate of treatment as well as the amount of flushing solution required to remove Zinc knowing the area of contamination and in-situ soil conditions. One of the potential sources of soil and ground water contamination with toxic metal ions is Effluent Treatment Plant sludge (ETP Sludge). The efficiency of soil washing technique was also studied on ETP Sludge using five leaching solutions i.e., distilled water, 0.1N HCl, 0.1N EDTA, 0.1N HCl+0.1N EDTA and 0.1N FeCl3. ETP sludge was collected at a filter press, KIADB industrial area, Doddaballapur, Bangalore. The removal efficiencies of these leaching solutions for removal of different metal ions (Copper, Zinc, Iron, Nickel, Cadmium, Lead and Chromium) were studied. The highest removal efficiencies were observed with 0.1N FeCl3 and 0.1N HCl+0.1N EDTA. The transport rates of different metals were determined which will be useful to estimate the quantity of leaching solution required in the field to remediate this sludge using soil washing technique. Even though soil washing technique is more effective than immobilization, for less permeable soil with more clay content, it is not a cost effective method. In such cases immobilization technique can be used to remediate the contaminated soil. The immobilized metals will not migrate through soil to groundwater and will not give adverse environmental hazards in their treated state. In the present study, immobilization technique was studied on two materials, (i) contaminated soil from open dump and (ii) ETP Sludge. The contaminated soil was collected from an open dump located at the Bingipura dumping yard, Bangalore and was tested for the presence of heavy metal ions. The efficiency of treatment to immobilize the metals was studied with different additives. The chemical agents with which can decrease the solubility product will be effective to immobilize the metal ions. The stabilizing agents used for treating these materials were lime water, NaOH and cement. These stabilizing agents were selected after preliminary batch tests. Since most of the heavy metals in soils become less mobile with increase in pH, the lime water / NaOH was added to the soil/sludge to adjust the pH of the mixture to 7.0, 8.5 and 10.0. The cement: soil ratios used were, 1:100 (pH=6. 8), 1:50 (pH=8. 1) and 1:25 (pH=9. 8) by weight. Leaching tests were conducted on the amended soils to know the long term efficiencies of the chemical agents for immobilizing the metal ions. The work carried out in this thesis is presented in different chapters as given below: For the design of the liner system, it is necessary to know the different contaminant transport processes, the determination of their rates and modeling. For remediation of contaminated soil, it is required to find the suitable remediation technique based on the amount and type of pollutants, the type of soil and other geological conditions. The detailed information about sources of heavy metals, effects of heavy metal contamination on health and the environment, contaminant transport processes, methods of determining transport rates, and different modeling techniques for contaminant transport are explained in Chapter 1. The Background information along with the scope and objectives of this study are presented in this chapter. The extensive review of literature related to column experiments, various solutions to Advection-Dispersion Equation, and different remediation techniques to treat the contaminated soil, is also presented in this chapter. Chapter 2 gives detailed information about various materials and methods used in this study. The characteristics of soils used in the present study and preparation of different chemical solutions were explained. The experimental procedures of batch tests, column tests and soil sectioning to determine the contaminant transport parameters were given in detail. The experimental procedures that are required for assessing the efficiency of soil washing technique i.e., Batch leach tests and column leach tests were also explained. The laboratory assessment of immobilization efficiency through leaching test was explained briefly. The analytical and numerical solutions used for this study were discussed in detail. This chapter also includes a method of prediction of breakthrough curves from the incomplete column test data. The contaminant transport parameters of metal ion Copper in two locally available soils i.e., Black cotton soil and Red soil were determined by various techniques i.e., Analytical (using MATLAB v7 software), semi-analytical (using POLLUTE v7 software), Explicit Finite Difference Method with two software tools (MATLAB v7 and M.S.EXCEL 2010), Implicit Finite Difference method with three schemes (BTCS, UPWIND & CRANK NICOLSON) using two software tools (MATLAB v7 and M.S.EXCEL 2010). Modifications were done in the spreadsheet solution of non-reactive solute available from the literature to incorporate the retardation factor as the solutes used in this study are reactive in nature. These results are presented in Chapter 3. The contaminant transport parameters determined for different test conditions (constant and variable source concentrations) and for different densities of soil are reported in this chapter. Determination of transport rates corresponding to maximum dry density using trend lines and preparation of design charts to estimate the thickness of the liner are also discussed in this chapter. The contaminant transport parameters were also determined for metal ion Zinc in the same soils with the same techniques as that of Copper and the migration rates were compared for both the ions. These models and comparative results are presented Chapter 4. It was observed that with increase in density, the dispersion coefficient decreases and Distribution coefficient increases. It was also found that the dispersion coefficient of Black Cotton Soil was lower than that of Red Soil whereas the distribution coefficient of Black Cotton soil is much higher than that of Red Soil. Further, it was observed that the dispersion coefficient of Copper was less than that of Zinc whereas the distribution coefficient of Copper was higher than Zinc. The design of liner thickness, based on transport rates of Zinc is briefly discussed in this chapter. A case study has been explained for the remediation of Zinc contaminated sandy soil using soil washing technique. The undisturbed soil samples collected from four locations of waste disposal site of Hindustan Zinc Limited located near Udaipur in Rajasthan State of Western India were assessed to find the suitable leaching solution and number of pore volumes for the effective removal of Zinc from this soil. The chelates/ solvents used for this soil were 0.1N HCl, 0.1N EDTA, 0.1N HCl+0.1N EDTA and 0.1N FeCl3. The contaminant transport parameters were also determined from the column leach tests based on the Leaching Mass Ratio approach and the results are presented in Chapter 5. From the experimental study it was observed that 0.1N FeCl3 and 0.1N HCl+0.1N EDTA are the most suitable leaching solutions to treat this soil. The Chapter 6 contains the sludge analysis of an industrial ETP sludge, column leach test results of this sludge with different leaching solutions, removal efficiencies of different solutions used and the transport rates of different contaminants. The leaching solutions used for this sludge were distilled water, 0.1N HCl, 0.1N EDTA, 0.1N HCl+0.1N EDTA and 0.1N FeCl3. It was observed that 0.1N FeCl3 and 0.1N HCl+0.1N EDTA are the most suitable leaching solutions to treat this sludge. Other solutions have also removed the contaminants by more than 50%, but the number of pore volumes required to leach out the contaminants was high. The order of removal efficiencies of different solutions is presented below: 0.1N FeCl3 > 0.1N HCl + 0.1N EDTA > 0.1N EDTA > 0.1N HCl > distilled water. The transport rates of different contaminants (Cu, Zn, Cd, Fe, Ni, Pb and Cr) were determined using analytical solution and are presented in this chapter. These transport rates are useful to estimate the quantity of leaching solution required in the field to remediate the sludge using soil washing technique. A contaminated soil collected from an open dump site within Bangalore city and ETP Sludge were analyzed to know the efficiency of immobilization/ solidification technique of remediation using three chemical agents lime, NaOH and cement. The soil samples were mixed with different proportions of these chemicals to adjust the pH of the mixtures to 7.0, 8.5 and 10.0. Leaching tests were conducted on the modified soils to know the long term efficiency of these chemical agents to immobilize the contaminants and these results are discussed in Chapter7. The results showed that highest immobilization efficiencies can be achieved with lime for this contaminated soil and cement is the most suitable chemical agent to treat this sludge. The immobilization efficiencies of different stabilizing agents for various metals were studied and the results analyzed. The Chapter 8 includes the major observations and conclusions of the present research work which will be useful for Geotechnical and Geo-environmental engineers to estimate the transport rates of contaminants, to design the soil liners, to assess the efficiency of soil washing technique to remediate the contaminated soil, to estimate the quantity of leaching solution required in the field for soil washing and to find the suitable chemical agent for remediating the contaminated soil by immobilization technique.

The SAPPI Ngodwana mill is the largest integrated pulp and paper mill in Africa and is situated in the Elands River catchment in the Mpumalanga province. A need has arisen at the mill to reduce effluent volumes requiring discharge. The combined mill effluent is currently irrigated onto pastures and over the years percolation of attenuated effluent has resulted in elevated chloride levels in the Elands River. Elevated chloride levels in the river have in turn impacted on the tobacco farmers downstream of the mill. Reclamation of Kraft Liner Board effluent was identified as a means of reducing the hydraulic load onto the irrigation pastures and at the same time reduce the intake of fresh water into the mill. Two possible uses for the reclaimed effluent, namely washing of bleached or unbleached pulp, were identified. The major reclaimed water quality variables of concern for re-use are; biodegradable organic material, colour and suspended solids. Approximately 9 months of pilot-scale activated sludge treatment of the effluent demonstrates that sufficient organic material can be removed for re-use, as wash water. Removal of the organic material was not influenced by sludge age in the range 2 to 8 days. A high degree of colour removal was achieved, which is contrary to reports in the literature. Even with the high colour removal achieved, however, insufficient colour was removed to allow washing of bleached pulp. Pulp and paper effluents are often reported to result in filamentous bulking activated sludges. This was confirmed in the testwork. Severe sludge settleability problems were experienced throughout the pilot-scale testwork. Filamentous bulking was identified as the cause of poor sludge settleability and preventative or control strategies would have to be implemented on full-scale.
Dissertation (MEng)--University of Pretoria, 2010.
Chemical Engineering
unrestricted

碩士
立德大學
資源環境研究所
96
The research adopted the biological process system parameter values and water quality data, included the temperature of aeration tank, the pH of aeration tank, inflow COD concentration of aeration tank, inflow SS concentration of aeration tank, inflow BOD concentration of aeration tank, the inflow rate of aeration tank, MLSS, SVI, return sludge concentration, F/M, HRT of aeration tank etc. dated from January of 2004 till September of 2004, of a wastewater treatment plant (WTP) located in an industrial park. Firstly, the data was normalized. Secondly, four simplified factors of “water quality factor”, “flow rate factor”, “sludge attribute factor” and “sludge loaded factor” were derived with the principal components analysis (PCA) in SPSS statistics software. Thirdly, the artificial neural networks (ANN), MATLAB 7.0 edition, was performed by inputting the four simplified factors and the effluent concentrations of COD and SS of the WTP were then predicted, respectively. The ANN was trained and verified with 959 and 221 sets of data, respectively. The correlation coefficient R between the predicted values and experimental data was used as a verification parameter. The R-values of COD and SS of 0.884 and 0.867 by the ANN method were found better than those of 0.797 and 0.721 by the PCA + ANN method, and those of 0.648 and 0.621 by the time series analysis, respectively. To further verify, a long term of 7 days prediction scheme was conducted and the predicted results were verified with the experimental data. Namely, parameter of relative value was calculated. The relative values of COD and SS of 9.6% and 13.1% by the ANN method were lower than those of 12.2% and 15.1% by the PCA + ANN method and those of 16.7% and 23.0% of ten times’ data by the time series analysis method, respectively.

Industrial effluents with high concentrations of heavy metals are widespread pollutants of great concerns as they are known to be persistent and non-degradable. Continuous monitoring and treatment of the effluents become pertinent because of their impacts on wastewater treatment plants. The aim of this study is to determine the correlation between heavy metal pollution in water and the location of industries in order to ascertain the effectiveness of the municipal waste water treatment plant. Heavy metal identification and physico-chemical analysis were done using Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) and multi-parameter probe respectively. Correlation coefficients of the measured values were done to investigate the effect of the industrial effluents on the treatment plants. Heavy metal resistant bacteria were identified and characterised by polymerase chain reaction and sequencing. Leeuwkuil wastewater treatment plants were effective in maintaining temperature, pH, and chemical oxygen demand within South Africa green drop and SAGG Standards whereas the purification plant was effective in maintaining the values of Cu, Zn, Al, temperature, BOD, COD, and TDS within the SANS and WHO standard for potable water. This findings indicated the need for the treatment plants to be reviewed.The industrial wastewater were identified as a point source of heavy metal pollution that influenced Leeuwkuil wastewater treatment plants and the purification plants in Vaal, Vereenining South Africa. Pseudomonas aeruginosa, Serratia marcescens, Bacillus sp. strain and Bacillus toyonensis that showed 100% similarity were found to be resistant to Al, Cu, Pb and Zn. These identified bacteria can be considered for further study in bioremediation.
Environmental Sciences
M. Sc. (Environmental Science)

碩士
國立中山大學
環境工程研究所
96
Growth of bacteria in drinking water distribution and storage systems can lead to the deterioration of water quality, violation of water standards, and increased operating costs. Growth or Regrowth results from viable bacteria surviving the disinfection process and utilizing nutrient in the water and biofilm to sustain growth. Factors other than nutrients that influence regrowth include temperature, residence time in mains and storage units, and the efficacy of disinfection. Tests to determine the potential for bacterial regrowth focus on the concentration of nutrients. Not all organic compounds are equally susceptible to microbial decomposition; the fraction that provides energy and carbon for bacterial growth has been called labile dissolved organic carbon, biodegradable organic carbon (BDOC), or Assimilable Organic Carbon (AOC). Easily measured chemical surrogates for AOC are not available now. As alternative to chemical methods, bioassays have been proposed. Assimilable Organic Carbon (AOC) is that portion of the biodegradable organic carbon that can be converted to cell mass and expressed as a carbon concentration by means of a conversion factor. In this study, two organisms, namely Psuedomonas fluorescens strain P17 and Spirillum species NOX were selected for the AOC determination. The growth of the bacteria was determined by periodic colony counts with spread plate technique on LLA (Lab-Lemco nutrient agar) cultivation medium until the growth reached maximum (maximum colony count, Nmax). Results showed that AOC follows a trend based on the climatic and seasonal changes (local climate) with peaks in summer and low during winter season and vice versa in term of AOC removing capability. In addition to confirm AOC removal rate in biofiltration bed was evaluated with a test column containing the same filling materials, Granular Activated Carbon (GAC). Long term test showed that GAC would last for forty weeks without any special treatment. Other result showed that biofiltration bed has a better removal efficiency rate 72% (average based on four year), than the test column 49% since it experience frequent back-washing, thus maintaining a healthy removal rate. In the test column change in total organic carbon was quite abnormal. AOC yearly distribution was also studied and differentiated into four stages. AOC removal of each stage was 48%, 70%, 83% and 77%. Total organic carbon concentration was much higher in the effluent 384 than influent 334 μg C/L; later methionine was found in water sample (effluent) which strongly suggests that the indigenous microbes had been reducing organic material such as cystein to methionine thus increasing the organic carbon content of the effluent. The microbial growths inside the GAC test column is entirely based on the long term feed of water at the treatment plant. Several other parameters such as Scanning Electron Microscope (SEM), Excitation Emissions Fluorescence Matrix (EEFM), Molecular Weight and Amino acids detection were selected and coupled with the AOC to shed light on the working mechanisms of both GAC as filtration material and characteristics of indigenous microbes towards the removal of organic contaminants and changes they can bring about to the quality of clear water.

碩士
中原大學
化學工程研究所
105
Due to climate change and the increasing demand of water for industry, Taiwan frequently faces an acute problem of water scarcity in recent years. Therefore, much attention has been paid for using reclaimed water to solve the problem of water shortage. Based on the effluents of domestic sewage and industrial waste water are large and stable water resources, the production of reclaimed water from these effluents will have great potential. In this study, membrane distillation was used for effluent treatment from Dihua sewage treatment plant (STP) to produce the reclaimed water. Experiments were divided into direct contact membrane distillation (DCMD) pilot test and air gap membrane distillation (AGMD) laboratory module test, the former was used for long-term data obtained while the latter was designed to implement the cleaning test for fouled membrane. In addition, simulation analysis for energy consumption of AGMD to produce reclaimed water from STP was also carried out in this study. Pilot DCMD test using flat sheet module with ePTFE membrane was conducted under feed temperature at 60℃and Re= 9500 while the permeate side at 35℃and Re=3200.The flux decline obtained by 4 hours operation per day and 2 month continuous operation is not significant, its value being about 15 kg/m²hr. Based on the measurement of conductivity in feed and permeate, respectively, to determine the ion rejection, results showed that the ion rejection reaches 99%. By measuring the Cl- ion concentration, it appeared that the rejection was 99.9%. SEM-EDS analysis for fouled membranes showed that the fouling components are mainly from organic matters. Based on the COD, Cl- and NH4+ measured from the produced water, it clearly indicated that the water quality from MD is better than that by RO. Experimental results of AGMD showed that 0.1 wt% NaOH or 0.8 wt% EDTA-4Na solution can wash away the fouling on the membrane surface and the cleaned membrane has flux nearly same as that from virgin membrane. Based on Memstill® concept for heat recovery, the thermal energy consumption of AGMD was also estimated. Under the given conditions of flat plate module 1x1 m2 , temperatures of feed inlet and after heater were at 80 and 30℃, respectively, and the superficial flow velocity in the module channel was 0.01 m/s, the thermal energy consumption estimated was 106.8 kWh/m3 and the flux was 5.5 kg/m2hr.

碩士
國立臺北科技大學
環境工程與管理研究所
96
The most common method of biological nitrogen removal is by combining the nitrification of the autotrophic nitrobacter and nitrosomonas with the denitrification of heterotrophic denitrifying bacteria. Autotrophic bacteria nitrify the organic nitrogen and ammonia, which are hydrolyzed amino acids or dead cells of microorganisms, into nitrite nitrogen and nitrate nitrogen. Subsequently, heterotrophic denitrifying bacteria are utilized in turn to reduce the total nitrate nitrogen to generate nitrite nitrogen and nitrogen gas. The latter evaporates out of water, thus completes the nitrogen removal process. However, due to the lack of carbon source after nitrification in the aeration tank, carbon source must be added during denitrification. The volatile materials in the sewage sludge make up approximately 60 ~ 80 % of total solids; the principal volatile composition consists of C, H. N and P. The water content and organic content of the resulted sewage sludge are very high; hence, they have features of large volume and are difficult to combust. In the process of reduction of sewage sludge, the process of converting sewage sludge to soluble state or ultra fine solids is called sewage sludge hydrolysis. The hydrolyzed products would then undergo further biological degradation, which would convert organic carbon to inorganic carbon, such as carbon dioxide and methane, to achieve the effect of reduction of sewage sludge. This study combined the two abovementioned principles of biological degradation. The Dihua Sewage Treatment Plant, for example, elevates the carbon source required by denitrification using reverse flow of anaerobically digested sewage sludge into bioreactor to achieve the purpose of reduction of sewage sludge. The bio-reactive systems of the Dihua Sewage Treatment Plant do not have nitrified fluid reverse flow design, but has the anaerobic sludge digestive system. Upon digestive process, the anaerobically digested sewage sludge is transformed into soluble or ultra fine materials; however, they are still in form of organic carbon, which is a favorable carbon source required by heterotrophic microorganisms in denitrification. In addition, it can further undergo a second bio-reaction to reduce the sludge amount, and the cost of subsequent sludge treatment and disposition in the Dihua Sewage Treatment Plant. However, the present actual operation in the Dihua Sewage Treatment Plant is to treat approximately 500 thousand tons of sewage daily, the water quality of which must meet the actual release criteria in order to reduce the total pollution load of the receiving water body (Tamshui River), and therefore, the experiment on reverse flow of nitrified sewage sludge to the bio-reactor can not be easily conducted. Accordingly, a simulation is conducted in this study using Bio Win Sewage Program Analysis Software developed by Canadian EnvironSim Corporation. Moreover, this study suggests utilizing the reference operation parameters under which the dual goals of optimal denitrification effect and sludge reduction are achieved by the Dihua Sewage Treatment Plant. The Dihua Sewage Treatment Plant have low influent concentration and do not have nitrified fluid reverse flow design. So those pH、dissolved oxygen、carbon source in anaerobic area can not do going denitrification. Presently the best parameter of The Dihua Sewage Treatment Plant biological treatmwnt is MLSS：1,500mg/L、dissolved oxygen：2.0mg/L、influent percentage：0.8：0.1：0.1、hydraulic residence time：4.7hr. The effluent quality is BOD：3.34 mg/L、COD：14.5 mg/L、SS：6.31 mg/L、TN：20.75 mg/L、Filtered TKN： 3.10 mg/L、 NH3-N：1.32 mg/L、NO3--N：2.65 mg/L、NO2--N：14.6 mg/L 、TP：1.56 mg/L. When the reverse percentage of anaerobically digested sludge is 0.2%, The effluent chemical oxygen demand be raised 0.6mg/L, sludge cake be decreased 4,634.1 kg/day. If influent percentage use 1.0：0.0：0.0, The effluent anmonia attenuate percentage from 91.32% be raised 94.46%.

碩士
國立中央大學
環境工程研究所
99
The objective of this study was initially aimed to evaluate the feasibility of using PAC and alum sludge, obtained individually in ordinary days and typhoon period from water treatment plants, as raw material for cement production. Then, based on the results of theoretical mixing design analysis of cement raw materials, the cement clinker was prepared when hydraulic modules (H.M.) = 1.7、2、2.3, silicate modules (S.M.) = 1.9、2.6、3.2, and iron modules (I.M.) = 1.5、2、2.5, respectively, and at different substitution rates (0%、50%、100%) of sludge for clay. Finally, the effects of various modules on the qualities of eco-cement were investigated. The experimental results indicated that the percentage of major chemical compositions of sludge from various water treatment plants were all within a certain range and the ash content was above 80%. In addition, the chemical compositions and crystalline phases of water treatment plant sludge (WTPS) were similar to those of clay. Therefore, the WTPS were appropriate to replace clay as one of cement raw materials. It also found that the mineral contents of clinker after sintering and cooling processes had no difference between cement raw materials with and without WTPS. However, at the condition of different cement modules, when hydraulic module was 2.3 produced the maximum amount of C3S (74.4%), while hydraulic module was 1.7 generated the maximum of C2S (59.27%). Furthermore, the contents of free lime in the 12 series cement clinker of this study were all less than 1％, and the weight loss after sintering were in the range of 31%~37%. These results meet the quality requirements for sintered cement clinker and resemble to Portland Type- I cement contained mineral substances of C3S, C2S, C3A, and C4AF. Moreover, this study selected the control group and hydraulic module groups that produced the maximum amount of C2S and C3S to further investigate the effect of temperature rising rate during the period of sintering process on the quality of eco-cement. The results revealed that the faster rate of temperature rising in the range of 1210 to 1410℃, the more intensity and production of crystalline phase of C2S and C3S occurred. Consequently, cement pastes were prepared from the clinkers sintered at a temperature rising rate of 20℃/min, and the microscopic analysis of the specimens was carried out. The experimental results found that C3S was the major product when hydraulic module = 2.3 and that lead to well hydration reaction and the best strength development at 7 days curing of the cement paste. However, due to the decrease of melting point when hydraulic module = 1.7, the cement clinker had melting phenomenon with ineffective formation of crystalline phase, which resulted in the lowest compressive strength of cement paste at the curing age of 28 days.