Dissertations / Theses on the topic 'On-site wastewater systems'

2 pp.<br>The conventional on-site household wastewater treatment system is known as the septic tank and absorption (leach) field. Local soil conditions; type, depth, texture and permeability all contribute to how well wastewater is treated as it moves toward groundwater. Soil conditions in parts of Arizona are not suitable for absorption fields, so alternative disposal systems are necessary. This article provides information on alternative disposal systems, the septic tank-mound system, and includes the description of the system, its background, where it should be used, and the cost and time consideration.

The development of southwest Virginia’s coal mining areas is severely hampered by a lack of building sites and waste disposal facilities. New technologies to reclaim mined lands have the capacity to produce large level expanses of land suitable for building sites by using the minespoil to reshape the land contours. Because these areas are generally too remote for centralized sewer to be economically feasible, the problem of waste disposal remains. Also, the current Virginia Department of Health regulations forbid placement of on-site waste water treatment and dispsoal systems (OSWTDS) in any fill material, including minespoil. The objective of this research is to examine alternative OSWTDS technologies for their applicability to treating wastewater in fill materials with respect to both removal of biological and chemical contaminants and hydraulic performance. In the fall of 1989, topsoil and minespoil materials were transported from southwest Virginia to Blacksburg, Virginia. The soil material was screened, air-dried, and packed into large plastic cylinders. Septic tank effluent and sand filter effluent was applied to the soil columns daily at three different loading rates for a period of 5 months. Wastewater samples were collected after passing through the soil columns and analyzed for several chemical parameters as well as fecal coliforms. Antibiotic-resistant Escherichia Coli and bacteriophage T-1 (virus) were introduced into the columns and analyzed in the filtrate. The soil material in the columns was also characterized for selected physical parameters. The results indicate that the concentration of total inorganic N was reduced 15 to 60% after the effluent was passed through the soil columns. However, the NO₃ - N concentrations were still above the 10 mg/L drinking water standard indicating that housing density should be considered when fill material is used for OSWTDS. The quantity of P emerging from the columns was higher than anticipated in minespoil column effluent which is probably related to the indigenous P present in the minespoil. The P concentration in topsoil column effluent increased with influent application and this relationship could be described by quadratic functions. The numbers of fecal coliforms were reduced (93 to 99%) by passing effluent through the soil columns. The concentration of indicator organisms indicated a gradual decline in viable bacterial cells and viral particles over time, with the indicator virus assays being completely negative by day 11. The tracer organism study also indicates that the survival time of these organisms can be effectively controlled in topsoil by reducing the influent loading rates, and in minespoil by reducing the influent loading rates and using some type of pretreatment, such as a sand filter. This study indicates that OSWTDS can be placed in selected topsoil areas in reclaimed minelands. It further indicates that at least 60 cm of unsaturated topsoil should be available for wastewater renovation. Minespoils were also effective at renovating wastewater, but may require pretreatment before application, a lower loading rate, a deeper unsaturated zone, or perhaps a combination of these factors.<br>Master of Science

Centralized wastewater treatment systems need substantial funds besides high-cost operation and maintenance programs, which could be considered unsuitable for low-income developing countries. As a solution, it becomes the trend towards on-site wastewater treatment systems (OWTs) due to its cost-effectiveness and flexibility of implementation and management. However, the keenness to implement these systems appropriately and monitor them continually is crucial to ensure that they do not impact the surrounding environment and human health. Constructed wetland is one of the on-site wastewater treatment systems. These systems are comparatively affordable alternative technology, and adequate systems for small communities, rural, and hilly areas. In the present study, two constructed wetlands as on-site wastewater treatment systems in Sakib - Jerash Governorate, Jordan, were investigated regarding systems performance, social acceptance, and cost-benefit analysis. The first system is a vertical flow constructed wetland (VCW) that has been operating since January 2020. The second system is a recirculation vertical flow constructed wetland (RVCW) that has been in operation since July 2015. The checking of the theoretical design parameter and the actual loading conditions of the septic tanks and wetlands in both systems showed that both implemented septic tanks and the wetlands are adequate and appropriate for the design goals. The wetlands’ treatment performance showed sufficient capability in organic matter removal efficiencies: Biochemical Oxygen Demand (BOD) and Chemical Oxygen Demand (COD), and Total Suspended Solids (TSS) removal efficiency. For pathogens: Total Coliform (TC) and Escherichia coli (E.coli), even though the removal efficiency was high, the effluents' values exceeded the local directive. Concerning nutrients removal, both systems showed low nitrogen and phosphorus removal efficiencies. Some suggestions and recommendations were proposed for improving nutrients removal and pathogen removal efficiencies. These recommendations were in desludging the septic tanks, replacing the filtering media, introduce plantation or add other carbon sources to the system, and using an additional aerobic filtration unit in the wetlands’ outlets. The study showed that the Jordanian society's nonacceptance of the on-site wastewater treatment systems could be handled through full transparency, educational workshops, and public participation. The latter contributed an increased sense of ownership robustly and increased concern of responsibilities on the operational and maintenance matters. Regarding the cost-benefit analysis, the study results demonstrated that the implementation of a constructed wetland as an on-site wastewater treatment system could be a beneficial and valuable alternative for clusters in rural areas and even in newly urbanized plans. The promising method for the treated wastewater's disinfection using clay minerals needs further investigation to determine the optimum clay mineral concentration on treatment and the needed time for exposure.<br>För att täcka centraliserade avloppsreningssystems drift och underhåll är det kapitalinsättningen av stor betydelse, förutom högkostnadsprogram, något som anses vara olämpligt för låginkomstländer. In-situ avloppsreningssystem verkar vara en lovande lösning till detta. För att dock säkerställa att dessa ej belastar den omgivande miljö och fungerar som det skall i förbehåll att dessa ständigt övervakas. Konstruerade våtmarker är en typ av in-situ vattenreningsteknik. Dessa system är lämpliga för småstäder, bergiga och tätortsområden. Dessa system är kostnadseffektiva och flexibla vad dess implementering och hantering anbelangar. Två dylika system är i fokus av denna studie, nämligen två konstruerade våtmarker i Sakib - Jerash i Jordanien och i synnerhet utforskas dess prestanda, social acceptans i och dessutom utfördes en nyttokostnadsanalys. Båda våtmarkerna i denna rapport har konstruerats med ett vertikalt markflöde och är i drift sedan januari 2020 och juli 2015 respektive. Dessa två system ger goda reduktioner med avseende på biokemiskt syrebehov och kemiskt syrebehov (BOD, COD), totalt suspenderat material (TSS), och effektivitet rörande patogen borttagning (TC och E. coli). Även om patogen borttagningseffektivitet i sig var hög förblev patogenhalt hög i det lokala direktivs avseende; de lokala förutsättningarna, nämligen designparameter och belastningsförhållanden, tillåter dock uppbyggande och drift av dessa två systemen som i fokus i detta studium. Beträffande borttagning av näringsämnen visade det sig att båda systemen har låg kväve- och fosforborttagningseffektivitet. Vissa förslag och rekommendationer föreslogs för att förbättra näringsämnen samt systemens effektivitet vad gäller patogenborttagning; i synnerhet dessa förslag beträffar pumpa ut slammet ur septiktanken, utbyte och backspolning av vattenfiltermedia, vattenväxterinförande eller tillägg av en extern kolkälla samt användning av en ytterligare aerobfiltreringsenhet vid utlopp. Det visade sig att det jordanska samhälle sätter käppar i hjulet vad gäller implementering av dessa våtmarker emedan dess förfarande är oacceptabelt. Dylika problem kan överbryggas genom full insyn, föredrag och workshops samt allmänhetens deltagande. Det sistnämnda gav upphov till en ökad känsla av äganderätt robust, något som ledde till ökat intresse för ansvar i drifts- och underhållsfrågor. Vad nyttokostnadsanalysen anbelangar visade det sig att implementering av ett dylikt system skulle vara fördelaktigt och värdefullt som alternativ för kluster på tätorts- och landsbygdsområden. Avloppsvattenbehandlingen med lermineraler verkar hittills vara en lovande metod vid betraktande av tidigare studier. Det behöver dock göras ytterligare undersökningar för avloppsvattenbehandlingen med lermineraler vid bestämmande av den optimala lermineral koncentration och dess exponeringstid.

The principal aims of this thesis were to examine whether there were hydraulic links between individual on-site wastewater systems in sandy soils at Salt Ash and the Tilgerry Creek estuary near Port Stephens, New South Wales, and whether the chemical and microbiological contaminants from on-site systems could reach surface and groundwaters, and possibly lead to impacts on estuarine oyster growing waters. The research outcomes are contained within the thesis and in four refereed papers presented at conferences, and which have been subsequently published, or are in press. Copies of each of these papers are contained within the thesis Appendices. The presence of faecal contamination from domestic systems in the estuary, and surface drains in particular, has been confirmed by work contained in this thesis. The potential level of risk to human health from the consumption of contaminated oysters is, however, regarded as very low, although an assessment of health risk using established microbial assessment models has not been undertaken<br>Doctor of Philosophy (PhD)

The use of on-site wastewater treatment systems (OWTS) for the treatment and dispersal of domestic effluent is common in urban fringe areas which are not serviced by centralised wastewater collection systems. However, due to inappropriate siting and soil characteristics, the failure of these systems has become a common scenario. The current standards and guidelines adopted by many local authorities for assessing suitable site and soil conditions for OWTS are increasingly coming under scrutiny due to the public health and environmental impacts caused by poorly performing systems, in particular septic tank-soil adsorption systems. In order to achieve sustainable on-site wastewater treatment with minimal impacts on the environment and public health, more appropriate means of assessment are required. The research described in the thesis details the processes adopted for the development and implementation of an integrated risk based approach to OWTS siting, design and management. This involved detailed investigations into resolution of some of the inherent deficiencies identified in the existing OWTS codes and guidelines, including more thorough site and soil assessment and data analysis, integration of the key risk facets of OWTS siting and design, environmental and public health, and the incorporation of scientific knowledge into the assessment processes. The research undertaken focused on four key research areas; (i) assessment of soil suitability for providing adequate treatment and dispersal of domestic wastewater; (ii) contamination of ground and surface waters as a result of OWTS failure and the major factors influencing contaminant fate and transport; (iii) assessment of environmental and public health risks due to poor OWTS performance; and (iv) the development of an integrated risk assessment framework for OWTS siting, design and management. The research conducted was multidisciplinary in nature, with detailed investigations of the physical, chemical and biological processes involved in on-site wastewater treatment and dispersal. This involved extensive field investigations, sampling, laboratory testing and detailed data analysis across the fields of soil science, groundwater and surface water quality, chemical and microbiological contamination, and contaminant fate and transport processes. The interactions between these different disciplines can be complex, resulting in large amounts of data being generated from the numerous field investigations and sampling processes undertaken. In order to understand the complex relationships that can occur, multivariate statistical techniques were utilised. The use of these techniques were extremely beneficial, as not only were the respective relationships between investigated parameters identified, but adequate decisions based on the respective correlations were formulated. This allowed a more appropriate assessment of the influential factors, and subsequently the inherent hazards related to OWTS, to be conducted. The primary research objectives for this research were investigated through a series of scientific papers centred on these key research disciplines. The assessment of soil suitability was achieved through extensive soil sampling throughout the study area and detailed laboratory testing and data analysis. The studies undertaken are described in Chapters 3, 4 and 5. Paper 1 (Framework for soil suitability evaluation for sewage effluent renovation) outlines a framework for assessing the renovation ability of the major soil groups located throughout Southeast Queensland. This framework formed the basis for the assessment of OWTS siting and design risks employed in the developed risk framework. Paper 2 (Use of Chemometric Methods and Multicriteria Decision-Making for Site Selection for Sustainable On-site Sewage Effluent Disposal) details and justifies the multivariate data analysis techniques used in establishing the soil framework. Paper 3 (Assessment of soil suitability for effluent renovation using undisturbed soil columns) describes investigations of the use of undisturbed soil cores for the assessment of long term soil renovation ability. This study was undertaken to validate the research outcomes achieved through the established framework developed in Paper 1. Papers 4, 5 and 6 (Chapters 6 - 8) focus on contamination issues of ground and surface waters resulting from poor OWTS treatment performance, and the different factors that influence pollutant fate and transport. The investigation of ground and surface water contamination, detailed in Paper 4 (Assessment of High Density of Onsite Wastewater Treatment Systems on a Shallow Groundwater Coastal Aquifer using PCA) and Paper 5 (Environmental and anthropogenic factors affecting fecal coliforms and E. coli in ground and surface waters in a coastal environment) was achieved through extensive ground and surface water sampling and testing from several monitored study sites. Analysis of the resulting data indicated that several key factors, including rainfall, site and soil conditions and on-site system density can significantly influence the fate and transportation of pollutants emitted from OWTS. An additional issue found during this research in assessing faecal contamination of water resources was the necessity to ensure that the respective sources of contamination were actually OWTS. The inherent difficulty in identifying the actual source of contamination was resolved by employing a source tracking method, namely antibiotic resistance analysis of faecal coliforms (Paper 6; Sourcing fecal pollution from onsite wastewater treatment systems in surface waters using antibiotic resistance analysis). Finally, Paper 7 (Integrated Risk Framework for On-site Wastewater Treatment Systems) describes the development of the final generic integrated risk assessment framework and how the outcomes, as discussed through the previous 6 papers, were combined to assess the environmental and public health risks inherent in OWTS siting and design. The outcomes of this research have significantly contributed to knowledge of best practice in OWTS siting, design and management. The developed soil suitability framework allows more appropriate assessment of soil characteristics for providing effluent renovation. This is generally not done in the current assessment techniques for OWTS. Additionally, the use of this framework incorporates scientific knowledge into the assessment of OWTS, allowing a more rigorous and scientifically robust assessment process. The processes and techniques used in the soil suitability framework, although based on the common soil types typical of South East Queensland, can be implemented in other regions, provided appropriate soil information is collected for the area of interest. The integrated risk framework has also been developed on a generic level, allowing easy implementation into most assessment processes. This gives the framework the flexibility to be developed for other areas specifically targeting the most influential OWTS siting and design factors, and the potential environmental and public health hazards within those regions. The resulting research outcomes achieved through the studies undertaken were subsequently applied to a case study for the development of the integrated risk framework for the Gold Coast region. The developed framework, based on scientific research, has allowed a more appropriate means of assessing site suitability for OWTS and appropriate management and mitigation of the environmental and public health risks inherent with poor OWTS performance

The use of on-site wastewater treatment systems (OWTS) for the treatment and dispersal of domestic effluent is common in urban fringe areas which are not serviced by centralised wastewater collection systems. However, due to inappropriate siting and soil characteristics, the failure of these systems has become a common scenario. The current standards and guidelines adopted by many local authorities for assessing suitable site and soil conditions for OWTS are increasingly coming under scrutiny due to the public health and environmental impacts caused by poorly performing systems, in particular septic tank-soil adsorption systems. In order to achieve sustainable on-site wastewater treatment with minimal impacts on the environment and public health, more appropriate means of assessment are required. The research described in the thesis details the processes adopted for the development and implementation of an integrated risk based approach to OWTS siting, design and management. This involved detailed investigations into resolution of some of the inherent deficiencies identified in the existing OWTS codes and guidelines, including more thorough site and soil assessment and data analysis, integration of the key risk facets of OWTS siting and design, environmental and public health, and the incorporation of scientific knowledge into the assessment processes. The research undertaken focused on four key research areas; (i) assessment of soil suitability for providing adequate treatment and dispersal of domestic wastewater; (ii) contamination of ground and surface waters as a result of OWTS failure and the major factors influencing contaminant fate and transport; (iii) assessment of environmental and public health risks due to poor OWTS performance; and (iv) the development of an integrated risk assessment framework for OWTS siting, design and management. The research conducted was multidisciplinary in nature, with detailed investigations of the physical, chemical and biological processes involved in on-site wastewater treatment and dispersal. This involved extensive field investigations, sampling, laboratory testing and detailed data analysis across the fields of soil science, groundwater and surface water quality, chemical and microbiological contamination, and contaminant fate and transport processes. The interactions between these different disciplines can be complex, resulting in large amounts of data being generated from the numerous field investigations and sampling processes undertaken. In order to understand the complex relationships that can occur, multivariate statistical techniques were utilised. The use of these techniques were extremely beneficial, as not only were the respective relationships between investigated parameters identified, but adequate decisions based on the respective correlations were formulated. This allowed a more appropriate assessment of the influential factors, and subsequently the inherent hazards related to OWTS, to be conducted. The primary research objectives for this research were investigated through a series of scientific papers centred on these key research disciplines. The assessment of soil suitability was achieved through extensive soil sampling throughout the study area and detailed laboratory testing and data analysis. The studies undertaken are described in Chapters 3, 4 and 5. Paper 1 (Framework for soil suitability evaluation for sewage effluent renovation) outlines a framework for assessing the renovation ability of the major soil groups located throughout Southeast Queensland. This framework formed the basis for the assessment of OWTS siting and design risks employed in the developed risk framework. Paper 2 (Use of Chemometric Methods and Multicriteria Decision-Making for Site Selection for Sustainable On-site Sewage Effluent Disposal) details and justifies the multivariate data analysis techniques used in establishing the soil framework. Paper 3 (Assessment of soil suitability for effluent renovation using undisturbed soil columns) describes investigations of the use of undisturbed soil cores for the assessment of long term soil renovation ability. This study was undertaken to validate the research outcomes achieved through the established framework developed in Paper 1. Papers 4, 5 and 6 (Chapters 6 - 8) focus on contamination issues of ground and surface waters resulting from poor OWTS treatment performance, and the different factors that influence pollutant fate and transport. The investigation of ground and surface water contamination, detailed in Paper 4 (Assessment of High Density of Onsite Wastewater Treatment Systems on a Shallow Groundwater Coastal Aquifer using PCA) and Paper 5 (Environmental and anthropogenic factors affecting fecal coliforms and E. coli in ground and surface waters in a coastal environment) was achieved through extensive ground and surface water sampling and testing from several monitored study sites. Analysis of the resulting data indicated that several key factors, including rainfall, site and soil conditions and on-site system density can significantly influence the fate and transportation of pollutants emitted from OWTS. An additional issue found during this research in assessing faecal contamination of water resources was the necessity to ensure that the respective sources of contamination were actually OWTS. The inherent difficulty in identifying the actual source of contamination was resolved by employing a source tracking method, namely antibiotic resistance analysis of faecal coliforms (Paper 6; Sourcing fecal pollution from onsite wastewater treatment systems in surface waters using antibiotic resistance analysis). Finally, Paper 7 (Integrated Risk Framework for On-site Wastewater Treatment Systems) describes the development of the final generic integrated risk assessment framework and how the outcomes, as discussed through the previous 6 papers, were combined to assess the environmental and public health risks inherent in OWTS siting and design. The outcomes of this research have significantly contributed to knowledge of best practice in OWTS siting, design and management. The developed soil suitability framework allows more appropriate assessment of soil characteristics for providing effluent renovation. This is generally not done in the current assessment techniques for OWTS. Additionally, the use of this framework incorporates scientific knowledge into the assessment of OWTS, allowing a more rigorous and scientifically robust assessment process. The processes and techniques used in the soil suitability framework, although based on the common soil types typical of South East Queensland, can be implemented in other regions, provided appropriate soil information is collected for the area of interest. The integrated risk framework has also been developed on a generic level, allowing easy implementation into most assessment processes. This gives the framework the flexibility to be developed for other areas specifically targeting the most influential OWTS siting and design factors, and the potential environmental and public health hazards within those regions. The resulting research outcomes achieved through the studies undertaken were subsequently applied to a case study for the development of the integrated risk framework for the Gold Coast region. The developed framework, based on scientific research, has allowed a more appropriate means of assessing site suitability for OWTS and appropriate management and mitigation of the environmental and public health risks inherent with poor OWTS performance

On-site wastewater treatment systems are among the main Swedish anthropogenic sources of nutrients causing euthropication of the Baltic Sea. Among on-site systems in Sweden almost half have septic tank treatment followed by a soil-based system, in which the wastewater is treated through soil filtration. In this study a soil based technique for on-site wastewater treatment is studied where wastewater is filtered through a sand filter. Composite samples of influent and effluent at two sand filters in the area of Stockholm are sampled to determine their chemical and biological function and to compare their treatment capacity to requirements. Parameters within the scope of the study are tot-P, NH4-N, DOC, pH, turbidity and dissolved oxygen. Biological function was considered to be good in both systems as nitrification was high and the effluent had sufficient levels of dissolved oxygen suggesting aerobic conditions. Prevailing aerobic conditions in the sand filters would also indicate good reduction of organic substances which is the case for DOC as it was reduced by above 85 % for one site and almost 70 % for the other site. The overall high reduction of organic micropollutants in the systems, reported in another study, also suggests that biological function when it comes to reduction of organic substances is good. On the other hand, chemical function, with respect to reduction of phosphorus, was not sufficient as none of the systems fulfilled the requirements from HaV for normal or high protection level. In the systems tot-P was reduced by 42 and 54 % respectively. A drawback with the method approach used in the study is that the obtained reduction results only can represent the actual situation if variations in incoming and outgoing flow, variations in influent concentrations and magnitude of dilution of effluent compared to daily wastewater load are small. As these are unknown in this case it adds uncertainty to the results.<br>Decentraliserade system för rening av avloppsvatten är bland de huvudsakliga svenska antropogena källorna till näringsämnen som bidrar till övergödning av Östersjön. Bland decentraliserade system i Sverige är nästan hälften system med slamavskiljare följt av ett markbaserat system i vilket avloppsvattnet renas genom infiltration i jord. I denna studie studeras en markbaserad teknik i vilken avloppsvattnet filtreras genom sand, en så kallad markbädd. En fältundersökning gjordes där samlingsprov av ingående och utgående avloppsvatten togs på två markbäddar i Stockholmsområdet för att bestämma deras biologiska och kemiska reningsfunktion samt att jämföra avskiljningen av fosfor i systemen med rekommendationer från HaV. Parametrar som inkluderats i studien är totalfosfor, ammonium-kväve, löst organiskt kol, pH, turbiditet och löst syre. Biologisk funktion ansågs bra i båda markbäddarna eftersom nitrifikationen var hög och utgående vatten hade tillräckliga halter av löst syre vilket implicerar att markbäddarna var väl syresatta. Rådande syrerika förhållanden i markbäddarna antyder också att organiskt material bryts ned avsevärt, vilket är fallet för löst kol som reducerades med mer än 85 % i en av markbäddarna och med nästan 70 % i den andra. Den höga reduktionen av organiska mikroföroreningar som påvisats i markbäddarna i en annan studie tyder också på att biologisk funktion med avseende på avsklijning av organiska substanser är bra. Kemisk funktion, med avseende på avskiljning av totalfosfor, var inte tillräcklig då ingen av markbäddarna levde upp till reduktionskraven från HaV för normal eller hög skyddsnivå. Totalfosfor avskiljdes med 42 respektive 54 % i markbäddarna. En nackdel med metoden som användes i studien är att de resultat som fåtts för avkiljning av de olika parametrarna endast kan representera den verkliga situationen om variationer i in- och utgående flöde samt variationer i ingående vattenkoncentrationer är små och om utspädningseffekten av utgående vatten är försumbar.

There are three important greenhouse gases: carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O), which are generated from the domestic wastewater treatment systems, including on-site and off-site sources. On-site emission of greenhouse gases occurs during process of wastewater treatment, while the off-site emission of greenhouse gases occurs during energy using and other supporting activities of the treatment system. The research established model to calculate greenhouse gas emissions from the domestic wastewater treatment systems, was named No.0 MTH model. The No.0 MTH model was based on balance equations of substrate and biomass, biochemical reactions and Monod kinetics equations for biological treatment reactors and writen by programing Scalable language. Model was calibrated and applied on the Yen So wastewater treatment plant, Ha Noi and the results were obtained at 22oC as follows: off-site GHG emission is 29,560 kgCO2-eq/day; on-site GHG emission is 13,534 kgCO2-eq/day, and the rate of on-site emission is 2.506 kgCO2-eq/ kg BOD. Maybe using the No.0 MTH model to calculate greenhouse gas emissions from the domestic wastewater treatment systems with similar biological methods.<br>Có 3 khí nhà kính quan trọng là khí Cacbonic (CO2), khí Mêtan (CH4), và khí Đinitơ monoxit (N2O) được phát sinh từ hệ thống xử lý nước thải sinh hoạt gồm cả nguồn trực tiếp và gián tiếp. Phát thải trực tiếp khí nhà kính (KHK) xảy ra trong suốt quá trình xử lý còn phát thải gián tiếp khí nhà kính xảy ra trong quá trình sử dụng năng lượng và các hoạt động phụ trợ bên ngoài hệ thống xử lý. Nghiên cứu đã thiết lập mô hình tính toán phát thải khí nhà kính từ hệ thống xử lý nước thải sinh hoạt, được đặt tên là mô hình MTH số 0. Mô hình MTH số 0 đã dựa trên các phương trình cân bằng khối lượng cơ chất và sinh khối, các phản ứng hóa sinh và phương trình Monod đối với các thiết bị xử lý sinh học và được viết trên ngôn ngữ lập trình scala. Mô hình đã được hiệu chỉnh và được áp dụng tính toán tại nhà máy xử lý nước thải sinh hoạt Yên Sở, thành phố Hà Nội và kết quả thu được tại 22oC như sau: phát thải KNK gián tiếp là 29.560 kgCO2-tđ/ngày và phát thải KNK trực tiếp là 13.534 kgCO2-tđ/ngày với tỷ lệ phát thải khí nhà kính trực tiếp là 2,506 kgCO2-tđ/ kgBOD. Có thể sử dụng mô hình MTH số 0 để tính toán phát thải khí nhà kính từ hệ thống xử lý nước thải sinh hoạt bằng phương pháp sinh học tương tự.

This thesis investigated the influence of septic tanks (ST) on stream water quality. Characterisation of septic tank effluent (STE) revealed that STE were enriched in phosphorus (P), nitrogen (N), organic matter (OM) and metals relative to stream waters and large proportions of these parameters were present in the soluble reactive forms. Human factors such as tank design, number of users, dishwasher use and infrequent desludging significantly (P < 0.05) influenced effluent quality. ST that received roof runoff had reduced effluent retention time, while infrequent desludging was linked to increased OM, bacteria and P concentration in the effluent. Tanks that served larger numbers of people had elevated microbial abundance, P and N concentrations. Effluent composition was not consistent throughout the year, but exhibited similarity in warmer drier months that was different from effluent in colder wetter months for biological oxygen demand and heavy metals. Effluent attenuation in a test soil revealed that 14%-35% of P was attenuated by sorption processes, while saccharin was strongly attenuated by soil microbial degradation. The complex composition of STE reduced the ability of the test soil to adsorb P, as other substances in the effluent were competing for soil binding sites. Calculated P annual loadings from STE were 0.797 and 0.956 kgP/person/year for water usage of 150 and 180 l/person/day, respectively, while, effluents P load from detergents was 0.154 kg P/person/year. Newly developed tracing studies showed that ratios of chloride to other effluent indicators (e.g. EC, NH4-N, TSS, turbidity, total coliforms, sucralose, saccharin and Zn) and the detection of effluent tryptophan-like peak by fluorescence spectroscopy may be useful in tracking effluent discharge to streams with low levels of dilution. However, effluent caffeine and saccharin were more effective tracers in streams with low and high levels of dilutions. A single individual tracer alone was not sufficient to evaluate STE contamination sources, but combined chemical and physical tracing approaches show promise as tools to identify STE inputs that continue to pose risks to watercourses and where mitigation measures could be effectively targeted.

In Ireland many people live in homes that are rurally located and not connected to public wastewater treatment systems. Where this is the case, the treatment of the wastewater produced must be undertaken by a private on-site wastewater treatment system (OSWTS). Properly built and maintained private on-site wastewater treatment systems can treat effluent in an ecologically sound manner and return the water to the environment. Nevertheless, inappropriately designed, installed and maintained systems can lead to the contamination of ground and surface water resources (Gray 1994; Daly, 2001; Flynn & Kroger, 2003; Gray, 2004; Gill et al, 2005; EPA, 2008; Daly & Craig, 2009 & Gormley, 2009). Such contamination can lead to significant threats to human health as well environmental degradation. The very high dependence by Ireland on these OSWTS’s for domestic wastewater treatment means that it is imperative that the performance and management of the systems is effective and robust. Unfortunately however there is evidence that a huge proportion of OSWTS’s are poorly managed, maintained and operated (EU, 2008; IOWA 2012 & GSI, 2013). This poor performance and management of OSWTS’s has resulted in significant prosecutions and fines for Ireland by the EU with clear and unambiguous conditions set down for what Ireland needs to do to avoid further sanctions. The existing legislation in Ireland for OSWTS’s and some recent amendments as a consequence of the prosecutions by the EU have made it very clear that the ultimate responsility lies with the homeowner for their wastewater treatment system. Provision is made in the legislation for a new inspection reigeme that will seek to identify pollution from OSWTS’s and attempt to mitigate the contamination of ground and surface waters in accordance with the requirements of the Water Framework Directive (WFD). This new inspection reigeme and the revisions to the legislation are required for Ireland to comply with the directions of the ECJ ruling (C188-08) in relation to OSWTS’s and so that the daily fines being imposed against Ireland are suspended. There has been little time available on foot of the ECJ (2008) ruling to educate homeowners on how they should be properly managing and maintaining their OSWTS’s to ensure that they operating effectively and efficiently. Existing research has identified that even where homeowners are aware of their responsibilities towards their OSWTS that they tend not to care with an ‘out of sight out of mind attitude (Gray, 2004). Clearly therefore the issue facing Ireland is not just a knowledge deficiency towards OSWTS’s but also a beahavioural change issue where people tend not to care about how their OSWTS performs. This thesis will examine the evolution of legislation in Ireland relating to OSWTS’s and how circumstances have led to the prosecution of Ireland (ECJ, 2009) for non compliance with the relevant EU Directives. Comprehensive literature reviews will outline existing research undertaken on the contamination of water resources by OSWTS in Ireland and also on techniques that could be utilised to educate homeowners on what they need to do to ensure that their individual wastewater treatment system is compliant with the relevant legislation. The research will adopt a number of research methods such as questionnaires and interviews to collect the data that is required to determine the knowledge that homeowners require about their OSWTS and this will shape the homeowner knowledge model that is to be developed. The publication of the research findings will inform the wastewater industry and the legislature of the key areas where homeowners are deficient in knowedge and understanding towards their OSWTS. These findings will also shape the knowledge model that will seek to address the knowledge and behavioural defieiciences that have led to Ireland being in the precarious position that it now finds itself in from the pollution, contamination and health threats associated with poorly performing and managed OSWTS’s. The implication of having relevant information and a clear understanding of where Ireland currently stands in relation the homowners and their interaction with their OSWTS’s will be of benefit to a whole range of sectors such as academia, industry, local authorities and the EPA. An accurate diagnosis of the problems relating to homeowner knowledge and behaiviour towards OSWTS’s will provide a framework to develop a lasting solution that will help in addressing pollution, groundwater contamination and the associated health risks from poorly constructed, managed and functioning OSWTS’s.

The use of on-site wastewater treatment systems for the treatment and dispersal of domestic effluent is common in urban fringe areas which are not serviced by centralised wastewater collection systems. However, due to inappropriate siting and inadequate evaluation of soil characteristics, the failure of these systems has become a common scenario. The current standards and guidelines adopted by many local authorities for assessing suitable site and soil conditions for on-site dispersal areas are coming under increasing scrutiny due to the public health and environmental impacts caused by poorly performing systems, in particular septic tank-soil adsorption systems. In order to achieve sustainable on-site wastewater treatment with minimal impacts on the environment and public health, more appropriate means of assessment of long term performance of on-site dispersal areas are required. The research described in the thesis details the investigations undertaken for the development of robust assessment criteria for on-site dispersal area siting and design and assessment of the long term performance of soil dispersal areas. The research undertaken focused on three key research areas; (i) assessment of site and soil suitability for providing adequate treatment and dispersal of domestic wastewater; (ii) understanding sorption, purification and transport processes influencing retention and release of pollutants and the natural controls governing these processes and (iii) the development of assessment criteria for long term behaviour of soils under effluent dispersal. The research conducted was multidisciplinary in nature, with detailed investigations of the physical and chemical processes involved in on-site wastewater treatment and dispersal. This involved extensive field investigations, sampling and monitoring, laboratory and soil column testing and detailed data analysis across the fields of soil science, groundwater quality, subsurface hydrology, chemical contamination, and contaminant fate and transport processes. The interactions between these different disciplines can be complex which resulted in substantial amounts of data being generated from the numerous field and laboratory investigations and sampling undertaken. In order to understand the complex relationships that can occur, multivariate statistical techniques were utilised. The use of these techniques was extremely beneficial. These techniques not only allowed not only the respective relationships between investigated parameters to be identified, but also adequate decisions based on the correlations were able to be formulated. This allowed a more appropriate assessment of the influential factors, and the prediction of ongoing changes to soil properties due to effluent disposal. The primary outcomes for this research were disseminated through a series of peer reviewed scientific papers centred on these key disciplines. The assessment of site and soil suitability was achieved through extensive soil sampling throughout the study areas and detailed laboratory testing and data analysis. The study identified and investigated the role of influential site and soil characteristics in the treatment performance of subsurface effluent dispersal areas. The extent of effluent travel and the ability of the soil to remove pollutants contained in the effluent by adsorption and/or nutrient uptake were investigated. A framework for assessing the renovation ability of the major soil groups located throughout Southeast Queensland was also developed. The outcomes provide a more rigorous scientific basis for assessing the ability of soil and evaluating site factors to develop more reliable methods for siting effluent dispersal areas. The resulting assessment criteria developed was compared with soil column studies to determine the robustness and validity of the outcomes. This allowed refinement of the assessment criteria in developing a more reliable approach to predicting long term behaviour of soils under sewage effluent dispersal. Multivariate techniques assisted in characterising appropriate soils and to determine their long-term suitability for effluent treatment and dispersal. The assessment criteria developed included physical, chemical and sub-surface hydrological properties of a site and soil which can be used to predict suitability for long term effluent treatment and dispersal. These include:  Moderate to slow drainage (permeability) to assist the movement of effluent (percolation) through the soil profile and allow adequate time for treatment and dispersal to occur. With longer percolation times, the opportunity for exchange and transport processes increase.  Significant soil cation exchange capacity and dominance of exchangeable Ca2+ or exchangeable Mg2+ over exchangeable Na+. Although a soil dominated by Mg2+ is found to promote dispersion of soil particles to some extent, its impact is far less than that of Na+. A stable soil would have a Ca: Mg ratio > 0.5.  Low exchangeable Na+ content to maintain soil stability.  Minimum depth of 400mm of potentially unsaturated soil before encountering a restrictive horizon, to permit adequate purification to take place.  Clay type with Illite and mixed mineralogy soils being the most sensitive to Na+. In general, significant increases in ESP occur in soils with 30 to 40% clay and in the presence of illite clay. Small amounts of smectite clays enhance treatment potential of a soil. The research outcomes have significantly contributed to the knowledge base on best practice in on-site dispersal area siting and design. The developed predictive site and soil suitability assessment criteria allows more appropriate evaluation of site and soil characteristics for providing long term effluent renovation. This is generally not done in the current assessment techniques for on-site dispersal areas. The processes and techniques used in the site and soil suitability assessment, although based on the common soil types typical of South East Queensland, can be implemented in other regions, provided appropriate soil information is collected or available. The predictive assessment criteria have been developed at a generic level, allowing easy implementation into most assessment processes. This gives the framework the flexibility to be developed for other areas specifically targeting the most influential on-site dispersal area siting and design factors, and assessment of long term performance under wastewater application.

The use of on-site wastewater treatment systems for the treatment and dispersal of domestic effluent is common in urban fringe areas which are not serviced by centralised wastewater collection systems. However, due to inappropriate siting and inadequate evaluation of soil characteristics, the failure of these systems has become a common scenario. The current standards and guidelines adopted by many local authorities for assessing suitable site and soil conditions for on-site dispersal areas are coming under increasing scrutiny due to the public health and environmental impacts caused by poorly performing systems, in particular septic tank-soil adsorption systems. In order to achieve sustainable on-site wastewater treatment with minimal impacts on the environment and public health, more appropriate means of assessment of long term performance of on-site dispersal areas are required. The research described in the thesis details the investigations undertaken for the development of robust assessment criteria for on-site dispersal area siting and design and assessment of the long term performance of soil dispersal areas. The research undertaken focused on three key research areas; (i) assessment of site and soil suitability for providing adequate treatment and dispersal of domestic wastewater; (ii) understanding sorption, purification and transport processes influencing retention and release of pollutants and the natural controls governing these processes and (iii) the development of assessment criteria for long term behaviour of soils under effluent dispersal. The research conducted was multidisciplinary in nature, with detailed investigations of the physical and chemical processes involved in on-site wastewater treatment and dispersal. This involved extensive field investigations, sampling and monitoring, laboratory and soil column testing and detailed data analysis across the fields of soil science, groundwater quality, subsurface hydrology, chemical contamination, and contaminant fate and transport processes. The interactions between these different disciplines can be complex which resulted in substantial amounts of data being generated from the numerous field and laboratory investigations and sampling undertaken. In order to understand the complex relationships that can occur, multivariate statistical techniques were utilised. The use of these techniques was extremely beneficial. These techniques not only allowed not only the respective relationships between investigated parameters to be identified, but also adequate decisions based on the correlations were able to be formulated. This allowed a more appropriate assessment of the influential factors, and the prediction of ongoing changes to soil properties due to effluent disposal. The primary outcomes for this research were disseminated through a series of peer reviewed scientific papers centred on these key disciplines. The assessment of site and soil suitability was achieved through extensive soil sampling throughout the study areas and detailed laboratory testing and data analysis. The study identified and investigated the role of influential site and soil characteristics in the treatment performance of subsurface effluent dispersal areas. The extent of effluent travel and the ability of the soil to remove pollutants contained in the effluent by adsorption and/or nutrient uptake were investigated. A framework for assessing the renovation ability of the major soil groups located throughout Southeast Queensland was also developed. The outcomes provide a more rigorous scientific basis for assessing the ability of soil and evaluating site factors to develop more reliable methods for siting effluent dispersal areas. The resulting assessment criteria developed was compared with soil column studies to determine the robustness and validity of the outcomes. This allowed refinement of the assessment criteria in developing a more reliable approach to predicting long term behaviour of soils under sewage effluent dispersal. Multivariate techniques assisted in characterising appropriate soils and to determine their long-term suitability for effluent treatment and dispersal. The assessment criteria developed included physical, chemical and sub-surface hydrological properties of a site and soil which can be used to predict suitability for long term effluent treatment and dispersal. These include:  Moderate to slow drainage (permeability) to assist the movement of effluent (percolation) through the soil profile and allow adequate time for treatment and dispersal to occur. With longer percolation times, the opportunity for exchange and transport processes increase.  Significant soil cation exchange capacity and dominance of exchangeable Ca2+ or exchangeable Mg2+ over exchangeable Na+. Although a soil dominated by Mg2+ is found to promote dispersion of soil particles to some extent, its impact is far less than that of Na+. A stable soil would have a Ca: Mg ratio > 0.5.  Low exchangeable Na+ content to maintain soil stability.  Minimum depth of 400mm of potentially unsaturated soil before encountering a restrictive horizon, to permit adequate purification to take place.  Clay type with Illite and mixed mineralogy soils being the most sensitive to Na+. In general, significant increases in ESP occur in soils with 30 to 40% clay and in the presence of illite clay. Small amounts of smectite clays enhance treatment potential of a soil. The research outcomes have significantly contributed to the knowledge base on best practice in on-site dispersal area siting and design. The developed predictive site and soil suitability assessment criteria allows more appropriate evaluation of site and soil characteristics for providing long term effluent renovation. This is generally not done in the current assessment techniques for on-site dispersal areas. The processes and techniques used in the site and soil suitability assessment, although based on the common soil types typical of South East Queensland, can be implemented in other regions, provided appropriate soil information is collected or available. The predictive assessment criteria have been developed at a generic level, allowing easy implementation into most assessment processes. This gives the framework the flexibility to be developed for other areas specifically targeting the most influential on-site dispersal area siting and design factors, and assessment of long term performance under wastewater application.

The Florida Showcase Green Envirohome (FSGE) incorporates many green technologies. FSGE is built to meet or exceed 12 green building guidelines and obtain 8 green building certificates. The two-story 3292 ft2 home is a "Near Zero-Loss Home", "Near Zero-Energy Home", "Near Zero-Runoff Home", and "Near Zero-Maintenance Home". It is spawned from the consumer-driven necessity to build a home resistant to hurricanes, tornadoes, floods, fire, mold, termites, impacts, and even earthquakes given up to 500% increase in insurance premiums in natural disaster zones, the dwindling flexibility and coverage of insurance policies, and rising energy, water and maintenance costs (FSGE 2008). The FSGE captures its stormwater runoff from the green roof, metal roof and wood decking area and routes it to the sustainable water cistern. Graywater from the home (after being disinfected using ozone) is also routed to the sustainable water cistern. This water stored in the sustainable water cistern is used for irrigation of the green roof, ground level landscape, and for toilet flushing water. This study was done in two phases. During phase one, only stormwater runoff from the green roof, metal roof and wood decking area is routed to the sustainable water cistern. Then, during phase two, the water from the graywater system is added to the sustainable water cistern. The sustainable water cistern quality is analyzed during both phases to determine if the water is acceptable for irrigation and also if it is suitable for use as toilet flushing water. The water quality of the sustainable cistern is acceptable for irrigation. The intent of the home is to not pollute the environment, so as much nutrients as possible should be removed from the wastewater before it is discharged into the groundwater. Thus, the FSGE design is to evaluate a new on-site sewage treatment and disposal (OSTD) system which consists of a sorption media labeled as Bold and GoldTM filtration media. The Bold and GoldTM filtration media is a mixture of tire crumb and other materials. This new OSTD system has sampling ports through the system to monitor the wastewater quality as it passes through. Also, the effluent wastewater quality is compared to that of a conventional system on the campus of the University of Central Florida. The cost-benefit optimization model focused on designing a residential home which incorporated a green roof, cistern and graywater systems. This model had two forms, the base model and the grey linear model. The base model used current average cost of construction of materials and installation. The grey model used an interval for the cost of construction materials and green roof energy savings. Both models included a probabilistic term to describe the rainfall amount. The cost and energy operation of a typical Florida home was used as a case study for these models. Also, some of the parameters of the model were varied to determine their effect on the results. The modeling showed that the FSGE 4500 gallon cistern design was cost effective in providing irrigation water. Also, the green roof area could have been smaller to be cost effective, because the green roof cost is relatively much higher than the cost of a regular roof.<br>M.S.Env.E.<br>Department of Civil and Environmental Engineering<br>Engineering and Computer Science<br>Environmental Engr MSEnvE

The principal aims of this thesis were to examine whether there were hydraulic links between individual on-site wastewater systems in sandy soils at Salt Ash and the Tilgerry Creek estuary near Port Stephens, New South Wales, and whether the chemical and microbiological contaminants from on-site systems could reach surface and groundwaters, and possibly lead to impacts on estuarine oyster growing waters. The research outcomes are contained within the thesis and in four refereed papers presented at conferences, and which have been subsequently published, or are in press. Copies of each of these papers are contained within the thesis Appendices. The presence of faecal contamination from domestic systems in the estuary, and surface drains in particular, has been confirmed by work contained in this thesis. The potential level of risk to human health from the consumption of contaminated oysters is, however, regarded as very low, although an assessment of health risk using established microbial assessment models has not been undertaken

”Rätt avlopp på rätt plats” – Livscykelanalys av tre enskilda avloppsanläggningar Problemen med övergödning i Östersjön och i Sveriges insjöar är stort och enskildaavlopp pekas ut som en central aktör, framförallt beträffande fosforutsläppen. I Sverigefinns det ungefär en miljon enskilda avloppssystem och nästan hälften av dessa har enså pass bristande vattenrening att de inte uppfyller gällande lagstiftning. Utvecklingenav nya tekniker för rening av avloppsvatten har länge strävat efter att minska utsläppenav övergödande ämnen, detta ibland på bekostnad av andra utsläpp, så somväxthusgaser och försurande ämnen.Det här examensarbetet har därför med hjälp av metodik från livscykelanalys (LCA)utvärderat tre enskilda avloppssystem med tanke på deras utsläpp av växthusgaser,försurande gaser samt övergödande ämnen. Då misstanke också fanns att de lokalaplatsegenskaperna påverkar de enskilda avloppssystemens totala miljöpåverkan,utfördes även en intervjustudie med ett antal av landets kommuner. I intervjustudiengjordes ett försök att identifiera de platsegenskaper som påverkar valet ochutformningen av de enskilda avloppssystemen. De tre avloppssystemen som ingick istudien är markbädd samt kompaktfilter i kombination med antingen ett reaktivt filtermed Polonite®, eller i kombination med kemfällning.Resultatet av studien visade att markbädden hade lägst utsläpp av både växthusgaseroch försurande gaser, men högst utsläpp av övergödande ämnen. De tvåfosforreducerande systemen uppvisade betydlig bättre potential för att reduceraövergödande ämnen, men detta på bekostnad av större utsläpp av växthusgaser ochförsurande gaser, speciellt i fallet med det reaktiva filtersystemet. Lokalaplatsegenskaper, så som näringsretention, visade sig spela en central roll för deundersökta avloppssystemens totala miljöpåverkan. I områden med hög fosforretentionunder vattnets väg till havet skulle avloppssystem med höga utsläpp av fosfor (så somdet markbaserade systemet) kunna vara försvarbara. På de platser i landet därövergödningen är problematisk finns det dock motiv för att använda fosforreducerandesystem.<br>"Right sewage system in the right place" - Life cycle assessment of three on-sitewastewater treatment options The problem with eutrophication in the Baltic Sea and in Swedish lakes is serious andon-site wastewater treatment systems are considered important, especially forphosphorus emissions. There exist about one million on-site wastewater treatmentsystems in Sweden and almost half of them do not meet current legislation.Development of new technologies for on-site wastewater treatment systems has for along time been focused on reducing emissions of eutrophying substances. However,there is a risk that this reduction could be achieved at the expense of other emissions,such as greenhouse gases and acidifying substances.This master thesis has therefore by use of life cycle assessment (LCA) evaluated threeon-site wastewater treatment systems considering their total emission of greenhousegases, acidifying gases and eutrophying substances. Because local site characteristicswere thought to affect the sewage systems overall environmental impact, an interviewstudy were also carried out with a number of municipal officials. The interview studywas designed to identify the local site characteristics that influence the selection anddesign of the on-site wastewater treatment systems. The three sewage systems includedin the study were a soil treatment system with surface water discharge and a compactbiological filter in combination with either a reactive filter module with Polonite®, or incombination with chemical precipitation.The results of the study reveal that the soil treatment system had the lowest emissions ofboth greenhouse gases and acidifying gases, but the largest emissions of eutrophyingsubstances. The two phosphorus reducing systems showed significantly greaterpotential to reduce the emissions of eutrophying substances, but at the expense of largeremissions of greenhouse gases and acidifying gases, especially in the case of thereactive filter system. Local site characteristics such as the retention of nutrients, provedto play a vital role in the investigated sewage systems overall environmental impact. Inareas with high retention of phosphorus sewage systems with high emissions ofphosphorus (such as the soil treatment system) where favored. However, in areas whereeutrophication is problematic, it is justified to use phosphorus reducing systems.

When designed, installed, and maintained properly, septic systems provide a cost-effective and environmentally-sound method to treat domestic wastewater. However, poor installation, unsuitable site conditions, and infrequent maintenance can lead to system failure and the discharge of partially-treated effluent to local waterways. As many as 1%, or 4,000 systems, fail each year in the Atlanta area. Therefore, the purpose of this paper is to evaluate what social and physical factors are significant to the location of on-site sewage management system failures in Cherokee County, Georgia. A regression analysis of the septic system failure rate, which was estimated with repair permit records from the local Board of Health, with Census demographics, soil, and septic system information found that the percent of soils in the “A” hydrologic group, unemployment rate, percent African-American population, population density, household size, percent of homes built between 1980 and 1989, percent built between 1970 and 1979, percent built between 1940 and 1949, and the average lot size of the parcels issued a repair permit were statistically-significant (p < 0.05) indicators of the failure rate at the Census block group level. The inclusion of socioeconomic, environmental, and physical characteristics suggests that the most effective response to reduce failures will incorporate actions to address these significant elements collectively. Despite restrictions on the ability of the Georgia Department of Public Health to regulate maintenance, many policy options are available to proactively identify areas with the greatest likelihood of failure and reduce the incidence of failure in those areas. Greater collaboration between stakeholders, including the county Board of Health and utility providers, improved record-keeping, and education and incentive programs provide the best opportunities to improve the management of septic systems in local jurisdictions.

Thesis (M.Phil. (School of Public Management and Planning))--University of Stellenbosch, 2007.<br>ENGLISH ABSTRACT: Water and sanitation is one of the key factors in the socio-economic development of a nation and people. Billions of people worldwide do not have access to clean water or basic sanitation leading to many health problems and developmental issues. This article discusses the challenges facing the world, South Africa and in particular the Western Cape and Cape Town in the provision of water and sanitation. For most people the desire is to have access to their own private portable water supply and their own private flush toilet connected via costly bulk water services to sewage treatment plants far away. The question posed is whether this model is sustainable into the future, given the water demands in many parts of the world affected by droughts and more violent weather cycles as a result of climate change and global warming. These factors will affect water supplies in South Africa and in particular the Western Cape and Cape Town. To answer some of the questions raised the Lynedoch EcoVillage development is discussed in detail in terms of sustainable neighbourhood planning and implementation. Sustainable Development is discussed, also various options in terms of applying ecological sanitation. The on-site water and sanitation system of the Lynedoch EcoVillage is discussed as a case study. The results of influent and effluent tests conducted by the CSIR are analysed to see whether the system is conforming to the Department of Water Affairs and Forestry standards for the use of effluent water in irrigation and re-use of water in toilets. Localised models of water and sanitation provision might thus be a way forward to satisfy the increasing demand for such services made on national and local authorities as urban areas increase in size and population.

Thesis (M.S.)--University of Wisconsin--Madison, 1995.<br>Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 49-52).

Thesis (M.S.)--University of Wisconsin--Madison, 1987.<br>Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 93-95).

Thesis (M.S.)--University of Wisconsin--Madison, 1995.<br>Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 176-178).

Thesis (M.S.)--University of Wisconsin--Madison, 1996.<br>Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 48-149).

Residential on-site wastewater systems (OWS) are a potential source of phosphorus (P) which can negatively impact surface water quality in rural watersheds. The magnitude of P loading from OWS is typically not monitored, and is further complicated when agricultural land-uses are intermixed with residential dwellings. Watershed-scale computer simulations are commonly used tools for evaluating the impacts of land-use changes on P loading. Existing models simulate OWS P treatment via vertical flow transport in native soils. However, in Nova Scotia (NS) OWS designs rely pre-dominantly on lateral flow and imported sand filter media. In this thesis, a watershed-scale computer modeling framework for simulating P loads from agriculture and lateral flow OWS designs was developed and tested. The framework consists of the P on-site wastewater simulator (POWSIM), designed specifically for this study, which is used in conjunction with the Soil and Water Assessment Tool (SWAT) model. The POWSIM loading tool has three computational components: (i) OWS disposal field design type selection and treatment media mass calculation; (ii) disposal field P treatment dynamics; and (iii) soil subsurface plume P treatment dynamics. The active P treatment media mass and dynamics equations were developed from numerical modeling (HYDRUS-2D) and lateral flow sand filter (LFSF) OWS disposal field experiments. A 2-part piecewise linear model was found to best represent LFSF P treatment processes. Testing of the modeling framework in the mixed land-use Thomas Brook Watershed (TBW) in NS demonstrated improved simulation of baseflow total P (TP) loads in both a predominantly residential subcatchment and one dominated by agriculture over the SWAT model without POWSIM. Different residential and agricultural development and beneficial management practice (BMP) scenarios were evaluated in the TBW. Agricultural BMPs were most effective at reducing cumulative TP loads while OWS BMPs were best at mitigating in-stream eutrophication impacts. The 50 year simulation period for the various scenarios found peak OWS TP loading occurring between 25 and 50 years, suggesting that modeling for many decades is required for proper evaluation. This study highlights the importance in identifying specific water quality issues that need to be targeted prior to implementing a BMP strategy.

Indiana University-Purdue University Indianapolis (IUPUI)<br>Underground septic systems thrive or fail based on the relationship with their local environment. This paper explores ways environmental variables such as soil type, tree roots, degree of slope, and impervious surfaces affect on-site wastewater treatment systems. It also discusses the effects each of these variables may have on a septic system, and the resulting impact a compromised system may have on the surrounding environment. This research focuses on an approximately 20 square mile area of central Washington Township in Marion County, Indiana. This area of central Indiana contains a large septic system owning population in a sampling of different environments such as wooded areas, hilly areas, and a variety of different soil types.