Journal articles: 'Phosphorus retention'

1

Boers, P. C. M., W. Van Raaphorst, and D. T. Van der Molen. "Phosphorus retention in sediments1." Water Science and Technology 37, no. 3 (February 1, 1998): 31–39. http://dx.doi.org/10.2166/wst.1998.0169.

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Phosphate is usually the most important growth limiting nutrient in aquatic environments. The availability of P is the result of external load and retention in the sediments. This latter is the result of a number of transport, microbial and chemical processes. The role of P in the productivity in systems and in the eutrophication process has initiated a large number of studies to the behaviour of P in sediments. Case studies in Veluwemeer, IJsselmeer, Wadden Sea and German Bight show that sorption on and binding in ferric (oxi)hydroxides, occlusion in calcium carbonates and authigenic mineral formation are the most important retention processes. However, all this research did not result in totally new approaches in lake restoration, nor did knowledge of internal P loading result in large scale applications of well-known sediment restoration techniques. It did result in more realistic expectations of lake restoration programmes. At the same time, renewed interest in the overall role of phosphate in the functioning and productivity of systems is emerging. The most important new items are: the role of the productivity is examined at large scale levels; the coupling of productivity with several large scale material cycles and global environmental problems and the study of the behaviour and fate of phosphate within the context of the functioning of entire watersheds.

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Delgado-González, Laura, Bruno Lartiges, Mathieu Gautier, Stéphane Troesch, and Pascal Molle. "Phosphorus retention by granulated apatite: assessing maximum retention capacity, kinetics and retention processes." Water Science and Technology 83, no. 4 (January 7, 2021): 792–802. http://dx.doi.org/10.2166/wst.2021.010.

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Abstract Natural apatites have previously shown a great capacity for phosphate retention from wastewater. However, its fine particle size distribution may lead to a premature clogging of the filter. Accordingly, a granulated apatite product was developed and manufactured in order to control the particle size distribution of the media. Experiments were conducted on laboratory columns to assess their phosphorus retention capacity, to identify the processes involved in phosphorus retention and to evaluate their kinetic rates. The results showed phosphorus retention capacities of 10.5 and 12.4 g PO4-P·kg−1 and kinetic rate coefficients in the range of 0.63 and 0.23 h−1 involving lower values than those found for natural apatites in previous studies. Scanning Electron Microscopy images showed that apatite particles in the granules were embedded in the binder and were not readily accessible to act as seeds for calcium phosphate precipitation. The retention processes differ depending on the supersaturation of the solution with respect to calcium phosphate phases: at low calcium concentrations (69.8 ± 3.9 mg·L−1), hydroxyapatite precipitates fill up the porosity of the binder up to a depth of 100–300 μm from the granule surface; at higher calcium concentrations (112.7 ± 7.4 mg·L−1) precipitation occurs at the granule surface, forming successive layers of hydroxyapatite and carbonated calcium phosphates.

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Maavara, Taylor, Christopher T. Parsons, Christine Ridenour, Severin Stojanovic, Hans H. Dürr, Helen R. Powley, and Philippe Van Cappellen. "Global phosphorus retention by river damming." Proceedings of the National Academy of Sciences 112, no. 51 (December 7, 2015): 15603–8. http://dx.doi.org/10.1073/pnas.1511797112.

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More than 70,000 large dams have been built worldwide. With growing water stress and demand for energy, this number will continue to increase in the foreseeable future. Damming greatly modifies the ecological functioning of river systems. In particular, dam reservoirs sequester nutrient elements and, hence, reduce downstream transfer of nutrients to floodplains, lakes, wetlands, and coastal marine environments. Here, we quantify the global impact of dams on the riverine fluxes and speciation of the limiting nutrient phosphorus (P), using a mechanistic modeling approach that accounts for the in-reservoir biogeochemical transformations of P. According to the model calculations, the mass of total P (TP) trapped in reservoirs nearly doubled between 1970 and 2000, reaching 42 Gmol y−1, or 12% of the global river TP load in 2000. Because of the current surge in dam building, we project that by 2030, about 17% of the global river TP load will be sequestered in reservoir sediments. The largest projected increases in TP and reactive P (RP) retention by damming will take place in Asia and South America, especially in the Yangtze, Mekong, and Amazon drainage basins. Despite the large P retention capacity of reservoirs, the export of RP from watersheds will continue to grow unless additional measures are taken to curb anthropogenic P emissions.

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4

Demars, B. O. L., D. M. Harper, J. A. Pitt, and R. Slaughter. "Impact of phosphorus control measures on in-river phosphorus retention associated with point source pollution." Hydrology and Earth System Sciences 9, no. 1/2 (June 14, 2005): 43–55. http://dx.doi.org/10.5194/hess-9-43-2005.

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Abstract. In-river phosphorus retention alters the quantity and timings of phosphorus delivery to downstream aquatic systems. Many intensive studies of in-river phosphorus retention have been carried out but generally on a short time scale (2-4 years). In this paper, monthly water quality data, collected by the Environment Agency of England and Wales over 12 years (1990-2001), were used to model daily phosphorus fluxes and monthly in-river phosphorus retention in the lowland calcareous River Wensum, Norfolk, UK. The calibrated model explained 79% and 89% of the observed variance before and after phosphorus control, respectively. A split test revealed that predicted TP loads were in good agreement with observed TP loads (r2=0.85), although TP loads were underestimated under high flow conditions. During relatively dry years, there was no net export of phosphorus from the catchment. High retention of phosphorus occurred, particularly during the summer months, which was not compensated for, by subsequent higher flow events. This was despite a relatively modest critical discharge (Q) above which net remobilisation occur. Phosphorus removal from the effluent at two major STWs (Sewage Treatment Works) reduced phosphorus retention but not the remobilisation. This may indicate that the presence of impoundments and weirs, or overbank flows may have more control on the phosphorus dynamics under high flow conditions. Further phosphorus remedial strategies will be necessary to prevent downstream risks of eutrophication occurring independently of the unpredictable variability in weather conditions. More research is also needed to quantify the impact of the weir and overbank flows on phosphorus dynamics.

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5

Al-Masri, M. R. "Absorption and endogenous excretion of phosphorus in growing broiler chicks, as influenced by calcium and phosphorus ratios in feed." British Journal of Nutrition 74, no. 3 (September 1995): 407–15. http://dx.doi.org/10.1079/bjn19950144.

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Absorption and endogenous excretion of P by male broiler chicks (14–29 d old) were quantitatively evaluated at different Ca: P ratios (1, 1:1; 2, 1·5:1; 3, 2:1; 4, 2·5:1) in four groups given experimental diets ad lib. The P content was the same in all diets. An isotope-dilution technique was used to determine endogenous faecal and renal excretion. Ca and P retentions in the whole body were estimated according to the comparative slaughter technique. P absorption was calculated from retention and endogenous excretion. Absorption and endogenous excretion of P amounted to (mg P/d per chick): 304, 270,160 and 158; and 135, 109, 31 and 30 in groups 1, 2, 3 and 4 respectively. Widening of the Ca:P ratio in the feed limited the P absorption. Availability of feed P amounted to (%): (1) 66, (2) 57, (3) 32 and (4) 30, and the amounts of absorbed P retained were (%): (1) 56, (2) 60, (3 and 4) 81. The increasing Ca concentration in the feed showed a greater effect on P absorption than on P retention. The ratios of relative retention to relative endogenous excretion of absorbed P were: (1) 1·27, (2) 1·50, (3 and 4) 4·26.

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6

Ige, D. V., O. O. Akinremi, and D. N. Flaten. "Evaluation of phosphorus retention equations for Manitoba soils." Canadian Journal of Soil Science 88, no. 3 (May 2, 2008): 327–35. http://dx.doi.org/10.4141/cjss07075.

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One of the key factors in phosphorus management is the P retention capacity (PRC) of the soil. In our previous study, we formulated several equations for estimating the phosphorus retention capacity of Manitoba soils. The objectives of the current study were to evaluate these equations using independent soil samples and to evaluate the influence of manure application on the predictive ability of these equations. Forty representative surface soil samples (20 soils with history of manure application and 20 without manure application history) were collected from across Manitoba. The P retention index (P150) and Langmuir adsorption maximum (Smax) were determined in the laboratory. The measured P retention capacities were then compared with those estimated using the formulated equations. Surprisingly, P150, which was obtained from a single measurement, was more robust than Smax that was obtained from at least 17 measurements as the equations provided a better estimate of P150 than Smax. Equations that were based on soil particle sizes (either percent clay or percent sand) provided poor estimates of soil PRC for the whole soil collection. However, when the soils were grouped on a pH basis, soil particle size worked better for soils with pH <7 than for soils with pH ≥7. The equations also worked better for soils with pH similar to those of the soils that were used to formulate the P retention equations. The accuracy of the predicted P sorption capacity improved with the manured soils due to the direct influence of manure application on soil properties that influence P retention such as Ca and Mg. Overall, the combination of CaM3, MgM3 and AlOx provided the best estimate of the PRC of Manitoba soils. Key words: Soil phosphorus, calcareous soils, phosphorus sorption, phosphorus retention, phosphorus retention capacity, estimating phosphorus retention capacity

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7

Pérez, M. M., J. Bossens, E. Rosa, and F. M. G. Tack. "Phosphorus retention capacity in red ferralitic soil." Water Science and Technology 70, no. 9 (September 30, 2014): 1561–68. http://dx.doi.org/10.2166/wst.2014.410.

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In this study the main physical–chemical characteristics of red ferralitic soil to use as substrate in subsurface wetlands was determined. The P-removal was evaluated in a short-term isotherm batch experiment and in a column percolation experiment. The acid characteristic and high content of iron minerals in the red ferralitic soil facilitated the phosphorus removal. Also the sorption isotherms at two different temperatures were obtained. The results showed that the sorption capacity increases with an increase in solution temperature from 25 to 35 °C. The experimental data were fitted to Langmuir and Freundlich models, having a better fit to the Freundlich isotherms. The maximum P-sorption capacities estimated using the Langmuir isotherm were 0.96 and 1.13 g/kg at 25 and 35 °C respectively. Moreover a column experiment was carried out at two different flows. Sequential extractions of the phosphorus-saturated soil indicated that phosphorus is mainly bound with iron or aluminum minerals. The results have demonstrated a good potential for red ferralitic soil for phosphorus removal from urban wastewater.

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8

Molete, S. F., C. C. du Preez, and M. V. Marake. "Retention of applied phosphorus by the benchmark soils of Lesotho and quantification of their phosphorus retention indices." South African Journal of Plant and Soil 22, no. 4 (January 2005): 214–22. http://dx.doi.org/10.1080/02571862.2005.10634710.

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9

Marcé, R., and J. Armengol. "Modeling nutrient in-stream processes at the watershed scale using Nutrient Spiralling metrics." Hydrology and Earth System Sciences 13, no. 7 (July 6, 2009): 953–67. http://dx.doi.org/10.5194/hess-13-953-2009.

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Abstract. One of the fundamental problems of using large-scale biogeochemical models is the uncertainty involved in aggregating the components of fine-scale deterministic models in watershed applications, and in extrapolating the results of field-scale measurements to larger spatial scales. Although spatial or temporal lumping may reduce the problem, information obtained during fine-scale research may not apply to lumped categories. Thus, the use of knowledge gained through fine-scale studies to predict coarse-scale phenomena is not straightforward. In this study, we used the nutrient uptake metrics defined in the Nutrient Spiralling concept to formulate the equations governing total phosphorus in-stream fate in a deterministic, watershed-scale biogeochemical model. Once the model was calibrated, fitted phosphorus retention metrics where put in context of global patterns of phosphorus retention variability. For this purpose, we calculated power regressions between phosphorus retention metrics, streamflow, and phosphorus concentration in water using published data from 66 streams worldwide, including both pristine and nutrient enriched streams. Performance of the calibrated model confirmed that the Nutrient Spiralling formulation is a convenient simplification of the biogeochemical transformations involved in total phosphorus in-stream fate. Thus, this approach may be helpful even for customary deterministic applications working at short time steps. The calibrated phosphorus retention metrics were comparable to field estimates from the study watershed, and showed high coherence with global patterns of retention metrics from streams of the world. In this sense, the fitted phosphorus retention metrics were similar to field values measured in other nutrient enriched streams. Analysis of the bibliographical data supports the view that nutrient enriched streams have lower phosphorus retention efficiency than pristine streams, and that this efficiency loss is maintained in a wide discharge range. This implies that both small and larger streams may be impacted by human activities in terms of nutrient retention capacity, suggesting that larger rivers located in human populated areas can exert considerable influence on phosphorus exports from watersheds. The role of biological activity in this efficiency loss showed by nutrient enriched streams remained uncertain, because the phosphorus mass transfer coefficient did not show consistent relationships with streamflow and phosphorus concentration in water. The heterogeneity of the compiled data and the possible role of additional inorganic processes on phosphorus in-stream dynamics may explain this. We suggest that more research on phosphorus dynamics at the reach scale is needed, specially in large, human impacted watercourses.

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10

Demars, B. O. L., D. M. Harper, J. A. Pitt, and R. Slaughter. "Impact of phosphorus control measures on in-river phosphorus retention associated with point source pollution." Hydrology and Earth System Sciences Discussions 2, no. 1 (January 13, 2005): 37–72. http://dx.doi.org/10.5194/hessd-2-37-2005.

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Abstract. In-river phosphorus retention alters the quantity and timings of phosphorus delivery to downstream aquatic systems. Many intensive studies of in-river phosphorus retention have been carried out but generally on a short time scale (2-4 years). In this paper, monthly water quality data, collected by the Environment Agency of England and Wales over 12 years (1990-2001), were used to model daily phosphorus fluxes and monthly in-river phosphorus retention in the lowland calcareous River Wensum, Norfolk, UK. The effectiveness of phosphorus stripping at two major sewage treatment works was quantified over different hydrological conditions. The model explained 78% and 88% of the observed variance before and after phosphorus control, respectively. During relatively dry years, there was no net export of phosphorus from the catchment. High retention of phosphorus occurred, particularly during the summer months, which was not compensated for, by subsequent higher flow events. The critical discharge (Q) above which net remobilisation would occur, was only reached during few, high flow events Q25-Q13. Phosphorus removal from the effluent at two major STWs (Sewage Treatment Works) reduced the phosphorus catchment mass balance variability by 20-24% under the Q99-Q1. range of flow conditions. Although the absorbing capacity of the catchment against human impact was remarkable, further phosphorus remedial strategies will be necessary to prevent downstream risks of eutrophication occuring independently of the unpredictable variability in weather conditions.

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11

Block, H. C., G. E. Erickson, and T. J. Klopfenstein. "Re-evaluation of Phosphorus Requirements and Phosphorus Retention of Feedlot Cattle1." Professional Animal Scientist 20, no. 4 (August 2004): 319–29. http://dx.doi.org/10.15232/s1080-7446(15)31321-8.

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12

Mitsch, William J., Julie K. Cronk, Xinyuan Wu, Robert W. Nairn, and Donald L. Hey. "Phosphorus Retention in Constructed Freshwater Riparian Marshes." Ecological Applications 5, no. 3 (August 1995): 830–45. http://dx.doi.org/10.2307/1941991.

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13

Ippolito, J. A., and N. O. Nelson. "Assessment of phosphorus retention in irrigation laterals." Journal of Soil and Water Conservation 68, no. 6 (November 1, 2013): 450–59. http://dx.doi.org/10.2489/jswc.68.6.450.

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14

Hejzlar, J., K. Šámalová, P. Boers, and B. Kronvang. "Modelling Phosphorus Retention in Lakes and Reservoirs." Water, Air, & Soil Pollution: Focus 6, no. 5-6 (December 6, 2006): 487–94. http://dx.doi.org/10.1007/s11267-006-9032-7.

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15

Richardson, C. J., S. Qian, C. B. Craft, and R. G. Qualls. "Predictive models for phosphorus retention in wetlands." Wetlands Ecology and Management 4, no. 3 (September 1996): 159–75. http://dx.doi.org/10.1007/bf01879235.

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16

Hartikainen, Salla H., and H. Helinä Hartikainen. "Phosphorus retention by phlogopite-rich mine tailings." Applied Geochemistry 23, no. 9 (September 2008): 2716–23. http://dx.doi.org/10.1016/j.apgeochem.2008.06.004.

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17

Braskerud, B. C., T. Hartnik, and Ø. Løvstad. "The effect of the redox-potential on the retention of phosphorus in a small constructed wetland." Water Science and Technology 51, no. 3-4 (February 1, 2005): 127–34. http://dx.doi.org/10.2166/wst.2005.0583.

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Building wetlands in small arable streams is a popular supplement to best management practice on arable fields. Particle bound phosphorus settles in the small constructed wetlands (CWs), receiving agricultural diffuse pollution. The sorption behavior of phosphorus is, however, redox-sensitive, and bound phosphorus may be remobilized in periods with low redox potential. This paper investigates changes in the redox potential in the free water of wetland Berg (Norway) during a three-year period, and how these redox changes affect the total phosphorus (TP) and total reactive phosphorus (TRP) retention. Despite eutrophic conditions in the wetland, the redox potential was never negative, and usually higher than 400 mV, indicating aerobic conditions. The relative retention was 44% and 43% for TP and TRP, respectively. The specific retention was 100 g TP and 43 g TRP m−2 yr−1. Loss of phosphorus was only observed during less than 19% of the total period of time. The net loss was less than 5% of the specific retention. The high positive redox potential probably conserves the redox-sensitive phosphorus in the wetland sediment as long as water flows through the CW.

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Povilaitis, Arvydas, Per Stålnacke, and Anatoly Vassiljev. "Nutrient retention and export to surface waters in Lithuanian and Estonian river basins." Hydrology Research 43, no. 4 (February 7, 2012): 359–73. http://dx.doi.org/10.2166/nh.2012.124.

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The statistical model MESAW was applied to simultaneously estimate export coefficients and retention of nutrients in four Lithuanian and three Estonian river basins (range 946–8,388 km2). This modelling approach uses non-linear regression to yield the export coefficients for total nitrogen and total phosphorus losses to surface waters, considering different land-use classes and retention of nutrients in the river network. The model was applied to data from 40 water quality monitoring sites and corresponding sub-basin data on land use, point sources and atmospheric deposition. The results showed that the studied river basins had a high nutrient retention capacity: 67–78 and 24–63% of total nitrogen and total phosphorus inputs remained in surface waters. The estimated retention was large in lakes: 27–59% for nitrogen and 11–31% for phosphorus. In-stream retention was apparently much lower, in the range 11–15% for total N and 3–12% for total P. Retention in lakes was lower in Estonia than in Lithuania due to the locations and smaller areas of the lakes in the Estonian basins. In Estonia, the highest relative retention in lakes was 46% for nitrogen and 35% for phosphorus. In-stream retention was also somewhat lower than in Lithuania, possibly because of the lower temperature in Estonian rivers in summer.

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Dantas Mendes, Lipe Renato. "Edge-of-Field Technologies for Phosphorus Retention from Agricultural Drainage Discharge." Applied Sciences 10, no. 2 (January 16, 2020): 634. http://dx.doi.org/10.3390/app10020634.

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Agriculture is often responsible for the eutrophication of surface waters due to the loss of phosphorus—a normally limiting nutrient in freshwater ecosystems. Tile-drained agricultural catchments tend to increase this problem by accelerating the transport of phosphorus through subsurface drains both in dissolved (reactive and organic phosphorus) and particulate (particle-bound phosphorus) forms. The reduction of excess phosphorus loads from agricultural catchments prior to reaching downstream surface waters is therefore necessary. Edge-of-field technologies have been investigated, developed and implemented in areas with excess phosphorus losses to receive and treat the drainage discharge, when measures at the farm-scale are not able to sufficiently reduce the loads. The implementation of these technologies shall base on the phosphorus dynamics of specific catchments (e.g., phosphorus load and dominant phosphorus form) in order to ensure that local retention goals are met. Widely accepted technologies include constructed wetlands, restored wetlands, vegetated buffer strips and filter materials. These have demonstrated a large variability in the retention of phosphorus, and results from the literature can help targeting specific catchment conditions with suitable technologies. This review provides a comprehensive analysis of the currently used edge-of-field technologies for phosphorus retention in tile-drained catchments, with great focus on performance, application and limitations.

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20

Zhang, Feng, Chang Qing Liu, Zhong Qiao, Gong Fa Chang, Yan Hui Qu, and Xue Jun Bi. "The Phosphorous Removal after Anaerobic Stages of Different Durations and under Different Organic Loadings in the Reversed A²/O Process." Advanced Materials Research 183-185 (January 2011): 1195–99. http://dx.doi.org/10.4028/www.scientific.net/amr.183-185.1195.

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The phosphorous removal behaviors under higher and moderate organic loading and after different durations of anaerobic stages were studied in the reversed A2/O process. Under both loading, the length of anaerobic stages did not significantly affect the subsequent aerobic phosphorus uptake efficiencies. Under higher loading, the available carbon sources are adequate, prolonging anaerobic stages led to more released phosphorus from phosphate accumulating organisms (PAOs). However, the phosphorus uptake rate in aerobic stage was almost the same as that of lower loading. At an anaerobic reaction time of 2.0 h, the corresponding specific aerobic phosphorus uptake rate achieved the highest value (6.13 mg/(L.h)). These results can help to determine the anaerobic hydraulic retention time in the reversed A2/O process.

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21

Pintar, J., B. Homen, K. Gazić, Z. Janječić, M. Sikirić, and T. Černy. "Effects of supplemental phytase on nutrient excretion and retention in broilers fed different cereal based diets." Czech Journal of Animal Science 50, No. 1 (December 5, 2011): 40–46. http://dx.doi.org/10.17221/3993-cjas.

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A 21-day experiment with day-old broilers was conducted in order to assess the effect of phytase supplementation to different cereals-soybean meal based diets on nitrogen, calcium, total and phytate phosphorus excretion and retention. Diets were formulated to contain 4 different cereals (maize, wheat, triticale and barley), 2 levels of dietary calcium (0.6 and 1.0%) and 3 levels of supplemental phytase (0, 500 and 1 000 PU/kg). Nutrient intake, excretion and retention were determined in the first three days of the 2nd and 3rd week of trial. The increasing phytase level resulted in reducing phytate phosphorus excretion and increasing its retention. Significant differences were obtained only in the 2nd week (excretion P < 0.024 and retention P < 0.044). Phytase supplementation significantly influenced total phosphorus excretion in the 3rd week (P < 0.048) and retention in the 2nd week (P < 0.015). The effects of 500 and 1 000 PU/kg were not statistically different from each other. No significant influence of phytase supplementation on nitrogen and calcium excretion and retention was observed.  

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Niu, Ming Fen, Si Li, Hong Jing Jiao, Jian Wei, Yuan Yang Sun, and Si Shen. "The Influence Factors in Denitrifying Phosphorus Removal." Applied Mechanics and Materials 401-403 (September 2013): 2084–87. http://dx.doi.org/10.4028/www.scientific.net/amm.401-403.2084.

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Denitrifying phosphorus removal can be achieved with the same matrix simultaneous nitrogen and phosphorus removal，is a hot topic of abroad study biological wastewater treatment，This is discussed the Influence factors of anoxic tank NO3- load, dissolved oxygen and the volume ratio of aerobic tank and anoxic tank, pH value of wastewater, sludge retention time (SRT), hydraulic retention time (HRT), mixed liquor suspended solids (MLSS) and temperature on denitrifying phosphorus removal, for denitrifying phosphorus removal process simulation, experimental research and practical application provides a reference and basis.

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Moosmann, Lorenz, René Gächter, Beat Müller, and Alfred Wüest. "Is phosphorus retention in autochthonous lake sediments controlled by oxygen or phosphorus?" Limnology and Oceanography 51, no. 1part2 (January 2006): 763–71. http://dx.doi.org/10.4319/lo.2006.51.1_part_2.0763.

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Huang, Chu-Long, Weifeng Kang, Su Xu, Bing Gao, Wei Huang, Zirong Li, and Shenghui Cui. "Growing phosphorus dilemma: The opportunity from aquatic systems' secondary phosphorus retention capacity." Science of The Total Environment 796 (November 2021): 148938. http://dx.doi.org/10.1016/j.scitotenv.2021.148938.

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Han, Wei, Linjiang Yuan, Lu Chai, Kai Zhao, and Guang Zhu Li. "The Effect of PHA on Enhanced Biological Phosphorus Removal." Advanced Materials Research 610-613 (December 2012): 1343–48. http://dx.doi.org/10.4028/www.scientific.net/amr.610-613.1343.

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Used A/O-SBR(anaerobic/aerobic alternating enhanced biological phosphorus removal system) to study carbon source and phosphate accumulating organisms (PAO) intracellular energy storage substance transformation, also studied PAO’s phosphorus removal capacity. PAO could uptake quick degradation organic matters and synthesis polyhydroxyalkanoates(PHA). PHA was a kind of intracellular energy storage substance, its content could affect PAO’s phosphorus removal capacity. When carbon source was plentiful, PAO could synthesis a lot of PHA, phosphorus removal capacity could reach 38.16 mgp/gvss. Sludge retention time could affect PAO synthesis PHA of quantity and structure. Along with the sludge retention time growth, intracellular PHA content was increased, and phosphorus uptake of desired aerobic time continues to decrease, so increasing the phosphorus removal efficiency. When the municipal sewage as carbon source, PHA was mainly composed of PHB(poly-ß-hydroxyvalerate) and PHV(poly-ß-hydroxyvalerate). Along with the sludge retention time prolongation, PAO could synthesis more PHV, PHB content was remain unchanged, PHA composition structure was changed.

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Vogel, Jason R., Rebecca A. Chavez, Saroj Kandel, and Glenn O. Brown. "Field Scale Demonstration of Fly Ash Amended Bioretention Cells for Stormwater Phosphorus Removal: A Review of 12 Years of Work." Water 13, no. 12 (June 10, 2021): 1632. http://dx.doi.org/10.3390/w13121632.

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In 2007, ten bioretention cells were constructed in Oklahoma as part of a full-scale technology project to demonstrate stormwater phosphorus reduction. The filter media used was amended with 5%, Class C fly ash by weight to increase phosphorus and heavy metal retention. In 2014, core samples were collected from four of the cells, and three were instrumented for continuous water monitoring for the following year. This paper will review the design, construction, computer modeling of phosphorus retention, and measured phosphorus removal after seven years of operation. Total phosphorus retained in the sampled cells showed reductions in effluent water concentrations of 68 to 75%, while total effluent mass reductions of 51 to 93% were achieved. Total phosphorus accumulation in the cells measured in cores ranged from 0.33 to 0.60 kg/year, which was somewhat greater than the annual calculated effluent reduction of 0.27 to 0.41 kg/year. While good, phosphorus retention was not as high as computer modeling predicted. Other research on the cells, including hydraulics, heavy metal adsorption, and microbial transport, is summarized. Experimental challenges with phosphorus extraction from samples are also discussed. All experience and results suggest that fly ash amendments are an effective option for phosphorus removal in bioretention cells.

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Molisani, MM, H. Becker, HS Barroso, CAG Hijo, TM Monte, GH Vasconcellos, and LD Lacerda. "The influence of castanhão reservoir on nutrient and suspended matter transport during rainy season in the ephemeral Jaguaribe river (CE, Brazil)." Brazilian Journal of Biology 73, no. 1 (February 2013): 115–23. http://dx.doi.org/10.1590/s1519-69842013000100013.

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Measurements of nutrient and suspended matter concentrations and loads entering and leaving the Castanhão reservoir during the rainy season were carried out to assess the influence of this large reservoir on land-sea fluvial transport in the ephemeral Jaguaribe river basin. Spatial variation indicated statistically significant attenuation of concentrations only for total phosphorous and suspended matter across the reservoir. Strong retention of nutrients and suspended matter loads by the reservoir was observed with average trapping efficiency of 89% for dissolved silicon, 98% of soluble reactive phosphorus, 71% for ammonium, 87% for total nitrogen, 98% for total phosphorus and 97% for suspended matter compared to the reservoir inflow. The dam operational procedure defined by the ephemeral conditions of the river reduced water releases compared to reservoir inflow and induced strong retention of nutrient and suspended matter loads within the reservoir when fluvial transfer occurs in this semiarid watershed.

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Kupatadze, Ketevan. "Investigation of phosphate-ion retention strenght in some types of Kakheti soils." Southern Brazilian Journal of Chemistry, Volume 27, No. 27, 2019 27, no. 27 (April 22, 2019): 1–7. http://dx.doi.org/10.37633/sbjc.27(27)2019.1-7.

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The presented article describes the soil types existing in east Georgia, particularly in several villages of Gurjaani Municipality-Vazisubani, Kalauri, Mukuzani, Shashiani. Meadow-brown and brown soils represent good soil types for viticulture development in Kakheti. The vineyards cultivated on these soils produce such wellknown wines as Tsinandali, Vazisubani, Mukuzani, Akhasheni, Gurjaani, Manavi. The study explores brown carbonate and meadow-brown soil lab tests to examine the absorption of phosphate ions by them. The study showed that the amount of phosphorus deposited through soils is sufficiently absorbed under various conditions, having a positive effect on the amount of crop. Was compared the rates of phosphate absorption in these soils with the efficiency of phosphorus fertilizers, which showed that the higher the absorption of phosphorus, the lower the amount of phosphorus available to the plant and the lower the yield, and the lower the strength of phosphorus retention, the higher the amount of phosphorus to be consumed by the plant and the higher the yield. But under the conditions of high cultivation degree, the strength of phosphorus absorption became weak, resulted in a large amount of exchangeable and movable phosphates already existing in the soil, which is available to the plant. So, the efficacy of phosphorus fertilizers on such soil is weak. The speed of phosphorus absorption in the soil of Gurjaani municipality villages is satisfactory. However, in case of a high degree of cultivation (or in case of excess fertilization), the degree of phosphorus retention decreases. Accordingly, phosphorus-containing fertilizers should be used within strictly controlled limits.

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29

KUPATADZE, Ketevan. "INVESTIGATION OF PHOSPHATE-ION RETENTION STRENGHT IN SOME TYPES OF KAKHETI SOILS." SOUTHERN BRAZILIAN JOURNAL OF CHEMISTRY 27, no. 27 (December 20, 2019): 1–7. http://dx.doi.org/10.48141/sbjchem.v27.n27.2019.7_2019.pdf.

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The presented article describes the soil types existing in east Georgia, particularly in several villages of Gurjaani Municipality-Vazisubani, Kalauri, Mukuzani, Shashiani. Meadow-brown and brown soils represent good soil types for viticulture development in Kakheti. The vineyards cultivated on these soils produce such wellknown wines as Tsinandali, Vazisubani, Mukuzani, Akhasheni, Gurjaani, Manavi. The study explores brown carbonate and meadow-brown soil lab tests to examine the absorption of phosphate ions by them. The study showed that the amount of phosphorus deposited through soils is sufficiently absorbed under various conditions, having a positive effect on the amount of crop. Was compared the rates of phosphate absorption in these soils with the efficiency of phosphorus fertilizers, which showed that the higher the absorption of phosphorus, the lower the amount of phosphorus available to the plant and the lower the yield, and the lower the strength of phosphorus retention, the higher the amount of phosphorus to be consumed by the plant and the higher the yield. But under the conditions of high cultivation degree, the strength of phosphorus absorption became weak, resulted in a large amount of exchangeable and movable phosphates already existing in the soil, which is available to the plant. So, the efficacy of phosphorus fertilizers on such soil is weak. The speed of phosphorus absorption in the soil of Gurjaani municipality villages is satisfactory. However, in case of a high degree of cultivation (or in case of excess fertilization), the degree of phosphorus retention decreases. Accordingly, phosphorus-containing fertilizers should be used within strictly controlled limits.

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30

Rustige, H., I. Tomac, and G. Höner. "Investigations on phosphorus retention in subsurface flow constructed wetlands." Water Science and Technology 48, no. 5 (September 1, 2003): 67–74. http://dx.doi.org/10.2166/wst.2003.0283.

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62 SSF sand-based constructed wetlands in Germany, Austria and Switzerland have been evaluated for their phosphorus performance. In addition intensive investigations on the removal of phosphorus and its accumulation within the filter bed were conducted at five wetlands. For the performance of horizontal flow (HF) reed beds a regression equation could be derived. This was not possible for vertical flow (VF) reed beds. The best removal efficiency was observed from HF systems with hydraulic loading rates of 10 mm d-1 or less. 50 percent of all investigated HF wetlands had an average P output concentration of less than 2.1 mg l-1 in comparison to 3.3 mg l-1 of VF wetlands. Saturation, seasonal and redox effects could be derived from time series analysis of the performance rate and further investigations of a well monitored VF reed bed. The retention of phosphorus was highest during the warm season. A small positive effect on phosphorus removal was observed with intermittent low redox levels. Soil analyses showed the highest accumulation of P within the influent zone of either HF or VF wetlands.

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31

D'Angelo, D. J., J. R. Webster, and E. F. Benfield. "Mechanisms of Stream Phosphorus Retention: An Experimental Study." Journal of the North American Benthological Society 10, no. 3 (September 1991): 225–37. http://dx.doi.org/10.2307/1467596.

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32

Kovács, Á., Zs Kozma, V. Istvánovics, and M. Honti. "Phosphorus retention patterns along the Tisza River, Hungary." Water Science and Technology 59, no. 2 (January 1, 2009): 391–97. http://dx.doi.org/10.2166/wst.2009.888.

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The aim of this study was to assess in-stream retention of suspended solids (SS) and total phosphorus (TP) at low flow condition in a large watercourse, the Tisza River. The analysis was based on a longitudinal water quality profile obtained in July 2006 during a cruise along the Hungarian section of the river (nearly 600 km). Water samples were taken manually for SS and TP every half an hour (ca. 5.5 km). Additionally, concentration of SS was calculated from on-line turbidity records taken every 6 s (ca. 10 m). Velocity field was calculated with a 1D hydrodynamic model calibrated for low flow conditions. To describe the transport, a simple first-order equation was adjusted to the SS profile after estimating the potential maximum of SS that the flow with the given velocity could transport. Specific P content of SS was related to velocity to estimate longitudinal TP profile. Retention of TP amounted to 42% along the Hungarian section of the Tisza River at a flow of 110 m3 s−1. Storage reservoirs significantly influenced the longitudinal retention pattern. Upstream of Dam II (river kilometre 404), net TP retention reached 73%, while the downstream section was a source of TP.

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33

Reddy, K. R., R. H. Kadlec, E. Flaig, and P. M. Gale. "Phosphorus Retention in Streams and Wetlands: A Review." Critical Reviews in Environmental Science and Technology 29, no. 1 (January 1999): 83–146. http://dx.doi.org/10.1080/10643389991259182.

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34

Ippolito, J. A., K. A. Barbarick, D. M. Heil, J. P. Chandler, and E. F. Redente. "Phosphorus Retention Mechanisms of a Water Treatment Residual." Journal of Environmental Quality 32, no. 5 (September 2003): 1857–64. http://dx.doi.org/10.2134/jeq2003.1857.

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35

Kolahchi, Zahra, and Mohsen Jalali. "Phosphorus Movement and Retention by Two Calcareous Soils." Soil and Sediment Contamination: An International Journal 22, no. 1 (January 2013): 21–38. http://dx.doi.org/10.1080/15320383.2012.697939.

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36

Stachelek, Joseph, and Patricia A. Soranno. "Does freshwater connectivity influence phosphorus retention in lakes?" Limnology and Oceanography 64, no. 4 (February 7, 2019): 1586–99. http://dx.doi.org/10.1002/lno.11137.

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37

RICHARDSON, C. J. "Mechanisms Controlling Phosphorus Retention Capacity in Freshwater Wetlands." Science 228, no. 4706 (June 21, 1985): 1424–27. http://dx.doi.org/10.1126/science.228.4706.1424.

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38

LaBaugh, James W. "Uncertainty in Phosphorus Retention, Williams Fork Reservoir, Colorado." Water Resources Research 21, no. 11 (November 1985): 1684–92. http://dx.doi.org/10.1029/wr021i011p01684.

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39

Svendsen, L. M., B. K. Kronvang, A. R. Laubel, S. E. Larsen, and B. Andersen. "Phosphorus retention in a Danish lowland river system." SIL Proceedings, 1922-2010 26, no. 3 (March 1998): 956–62. http://dx.doi.org/10.1080/03680770.1995.11900860.

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40

Audet, Joachim, Dominik Zak, Jørgen Bidstrup, and Carl Christian Hoffmann. "Nitrogen and phosphorus retention in Danish restored wetlands." Ambio 49, no. 1 (April 16, 2019): 324–36. http://dx.doi.org/10.1007/s13280-019-01181-2.

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41

Ketaren, P. P., E. S. Batterham, E. Belinda Dettmann, and D. J. Farrell. "Phosphorus studies in pigs." British Journal of Nutrition 70, no. 1 (July 1993): 269–88. http://dx.doi.org/10.1079/bjn19930122.

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Experiments were conducted with pigs and rats to determine the availability of P in feeds. Initially, the availability of P in a soya-bean meal and field peas (Pisum sativum cultivar Early Dun) was assessed using a slope–ratio assay for grower pigs. Three different levels of either monosodium phosphate (MSP), soya-bean meal or field peas were added to a basal sucrose–soya-bean meal diet (2·5 g/kg P) to give three levels of P (3·0, 3·5 and 4 g/kg) for each source. The diets were offered for 35 d at three times maintenance energy requirements to female pigs initially weighing 20 kg live weight. Several bone variables and the ash and P concentration and retention levels in the empty body were used as criteria of availability. The responses to MSP were linear for all variables. However, responses to P in the test proteins, particularly soya-bean meal, were mostly non-linear, except for ash and P concentrations and retentions in the empty body. The estimates of P availability in the soya-bean meal and in the field peas were dependent on the criteria used to assess availability. Using bone variables as the criterion, the availabilities of P in soya-bean meal and field peas were approximately 0·17 and 0·38 respectively. Using ash or P concentrations or retentions in the empty body as the response criterion, the availabilities of P in soya-bean meal and field peas were 0·61 and 0·38 respectively. The mean retention values for P from MSP, soya-bean meal and field peas were 0·74, 0·33 and 0·21 respectively. Experiments were then conducted to define the conditions necessary for a slope–ratio assay for P availability with growing rats to determine if they could be used as a model to assess P availability for pigs. These experiments examined level of P in the diet, the effect of Ca:P ratio and criteria for assessing response (growth rate, feed intake, feed conversion ratio, bone ash and bone bending moment). The results indicated that a suitable range of dietary P for a slope–ratio assay in rats was 1·8–3·5 g/kg, with Ca: P ratio of between 1·3 and 6·2, and that ash content or bone bending moment of the femur bone were suitable criteria of response. However, using bone bending moment as the criterion of response, the availability of P in soya- bean meal was 0·81, which was considerably higher than the estimate with pigs. Overall the results indicated that the estimates of the availability of P in feeds for pigs were dependent on the criteria used to assess availability and that the value for rats led to an overestimate of the value for pigs.

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42

Mizuki, Kensuke, and Masahiko Katoh. "Phosphorus recovery from soil through phosphorus extraction and retention on material: A comparison between batch extraction-retention and column percolation." Journal of Environmental Management 277 (January 2021): 111435. http://dx.doi.org/10.1016/j.jenvman.2020.111435.

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43

Mikola, Anna, Jyri Rautiainen, and Riku Vahala. "Secondary clarifier conditions conducting to secondary phosphorus release in a BNR plant." Water Science and Technology 60, no. 9 (November 1, 2009): 2413–18. http://dx.doi.org/10.2166/wst.2009.601.

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A full-scale study at Pihlajaniemi BNR plant in Savonlinna Finland investigated in detail the conditions in which phosphorus release in the secondary clarifier can occur. For this purpose nutrient and ORP profiles were taken in different process conditions from the sludge blanket in the secondary clarifiers. The results show that in anaerobic conditions secondary phosphorus release can take place in the secondary clarifiers without any addition of exogenous COD. Long sludge retention time in the secondary clarifier was a prerequisite of anaerobic conditions in the sludge blanket, but retention time required varied with seasons and process conditions. Some indications of simultaneous phosphorus release and denitrification without COD input was also found. The re-absorption of the released phosphorus was observed in those parts of the sludge blanket, where nitrates were present. Even with very long sludge retention times the released phosphorus stayed inside the sludge blanket and it did not impair the effluent quality. An 18 month follow-up of the BNR process revealed, however, that occasionally dissolved phosphorus escaped from the sludge blanket. It was suggested, that this was the consequence of the missing nitrate containing layer at the upper part of the sludge blanket.

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44

Sárdi, Katalin, and P. Csathó. "Studies on the Phosphorus Retention of Different Soil Types in a Pot Experiment with Perennial Ryegrass." Agrokémia és Talajtan 51, no. 1-2 (March 1, 2002): 177–84. http://dx.doi.org/10.1556/agrokem.51.2002.1-2.21.

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Differences in soil properties and among plant species may play an important role in the effectiveness of residual and freshly applied phosphorus fertilizers. However, a limited number of experimental results are available on this subject. Pot experiments were carried out with soils from 9 sites of the National Long-term Fertilization Trials, varying in their main characteristics, such as pH, soil texture, organic matter content and P status. Soil samples were taken after 20 years from the unfertilized control and from plots annually fertilized with 200 kg P 2 O 5 .ha -1 . Effects of long-term fertilization as well as that of freshly applied phosphorus were studied in the experiments. Perennial ryegrass (Lolium perenne L.) was used as test plant. The objective of the present study was to develop quantitative relationships between selected soil parameters and the phosphorus retention characteristics of the experimental soils. Amounts of P removed by plants during 5 cuts were correlated with DM production of plants as well as with the phosphorus amounts extracted at pH 3.7 by ammonium lactate-acetic acid, AL-P mg.kg -1 soil. Phosphorus nutrient balance was calculated from the results to evaluate either P supply or retention characteristics of experimental soils. Results of the experiments were computed by stepwise regression analyses using the STATGRAPHICS program package. Soil parameters involved in the study were: humus content, pH values (ranging from 3.9 to 7.4), clay mineralogy, total P contents of soils, P rates applied for 20 years, freshly applied P in the pot experiment. Based on the results of regression analyses, the importance of soil parameters was evaluated. It was established that several soil parameters significantly influenced the phosphorus retention of soils. Regression coefficients (R²) ranged between 0.619 and 0.285 (n = 86). Long-term effects of P application, higher pH values and humus content had a favourable influence on the P retention of experimental soils. On the other hand, increasing phosphorus retention could be attributed to higher CEC, vermiculite content as well as to increasing rates of freshly applied phosphorus. It was found that long-term effects of P applications on the P supplying power of soils were related also to the increasing N and K rates, providing a balanced nutrient supply in soils. Our results may help the broader understanding of phosphorus retention and fixation characteristics under various soil conditions.

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Cao, Jinxiang, Xiaoxing Hong, and Guofeng Pei. "Removal and retention of phosphorus by periphyton from wastewater with high organic load." Water Science and Technology 70, no. 1 (April 22, 2014): 62–69. http://dx.doi.org/10.2166/wst.2014.195.

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The total phosphorus (TP) removal efficiency from organic wastewater (pig farm and distillery wastewater) were estimated by using filamentous green algae (FGA) and benthic algal mats (BAM) treatment systems under laboratory conditions, and the contents of periphyton phosphorus fractions were determined by using a sequential extraction. The removal rates of TP reached 59–78% within the first 8 days of all treatment systems and could achieve average 80% during 30 day period, and the phosphorus removal rates by using BAM was higher than that of FGA. The ability of retention TP of periphyton enhanced gradually, the BAM TP contents were higher than that of FGA, the highest TP concentrations of BAM and FGA were 26.24 and 10.52 mg P g−1·dry weight. Inorganic phosphorus (IP) always exceeded 67.5% of TP, but the organic phosphorus fraction only made up less than 20% of TP. The calcium-binding phosphorus (Ca-P) was the dominant fraction and its relative contribution to TP was more than 40%. The TP was also strongly and positively correlated with the IP and Ca-P (p < 0.01) in periphyton. It showed that the periphyton had a potential ability of rapid phosphorus removing and remarkable retention from wastewater with high load phosphorus.

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46

Noormazni, M., J. H. Kim, S. Harada, S. Narita, and K. Takahashi. "Phosphorus recovery from highly concentrated phosphate-ion groundwater by calcium-carrying chaff charcoal." Water Practice and Technology 10, no. 2 (June 1, 2015): 347–54. http://dx.doi.org/10.2166/wpt.2015.041.

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The chaff produced during the crop season that was attached with calcium was used in an upward type column for the purpose of recovering highly accumulated phosphorus in groundwater. The amount of phosphorus recovery obtained in various hydraulic retention time was 1.5–2.0 mg per 1 g of chaff. Owing to the reaction of calcium on the surface of chaff charcoal with phosphate ion in groundwater, calcium phosphate compound was produced and might be existed as hardly soluble calcium phosphate as it did not elute in citric acid. Thus, phosphorus recovered could not be directly used as fertilizer. It needed support from mycorrhizal fungi in soils, rainwater, etc. to be usable for the farmland. It was also confirmed that pH value was an effective indicator in phosphorus recovery performance because the results show that concentration of phosphate ion in treated water was depend on pH value. Phosphorous recovery using calcium-carrying chaff charcoal is expected to mitigate the severe eutrophication problems at Hachiro Lake.

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47

Misiura, Maciej M., João A. N. Filipe, Carrie L. Walk, and Ilias Kyriazakis. "How do pigs deal with dietary phosphorus deficiency?" British Journal of Nutrition 124, no. 3 (March 16, 2020): 256–72. http://dx.doi.org/10.1017/s0007114520000975.

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AbstractFeeding strategies for growing monogastric livestock (particularly pigs) must focus on maximising animal performance, while attempting to reduce environmental P load. Achieving these goals requires a comprehensive understanding of how different P feeding strategies affect animal responses and an ability to predict P retention. Although along with Ca, P is the most researched macromineral in pig nutrition, knowledge gaps still exist in relation to: (1) the effects of P feed content on feed intake (FI); (2) the impact of P intake on body composition; (3) the distribution of absorbed P to pools within the body. Here, we address these knowledge gaps by gathering empirical evidence on the effects of P-deficient feeds and by developing a predictive, mechanistic model of P utilisation and retention incorporating this evidence. Based on our statistical analyses of published literature data, we found: (1) no change in FI response in pigs given lower P feed contents; (2) the body ash–protein relationship to be dependent upon feed composition, with the isometric relationship only holding for pigs given balanced feeds and (3) the priority to be given towards P retention in soft tissue over P retention in bones. Subsequent results of the mechanistic model of P retention indicated that a potential reduction in P feeding recommendations could be possible without compromising average daily gain; however, such a reduction would impact P deposition in bones. Our study enhances our current knowledge of P utilisation and by extension excretion and could contribute towards developing more accurate P feeding guidelines.

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Stewart Jr., C. Neal, and Erik T. Nilsen. "Drosera rotundifolia growth and nutrition in a natural population with special reference to the significance of insectivory." Canadian Journal of Botany 70, no. 7 (July 1, 1992): 1409–16. http://dx.doi.org/10.1139/b92-177.

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The impact of nutrient addition on growth and nutrient accumulation in Drosera rotundifolia was studied in a field population. Experiments were performed by exclosing insects and (or) adding phosphorus and (or) nitrogen to soil. Drosera rotundifolia did not significantly benefit from insect capture nutritionally or energetically in native or nutritionally enhanced soils. Added nutrients to the soil or supplemental foliar insect feeding decreased phosphorus retention in hibernacula by 50%. Nutrient additions reduced D. rotundifolia vegetative growth in both N and P addition treatments. In addition, allocation to reproduction (inflorescences) decreased by 98% when N was added to the soil. Phosphorus retention in hibernacula was especially high in plots in which no nutrients were added via the soil or by insect applications. Although not statistically significant, flower stalk density and floral biomass were greater where insects were available to plants. The data from this study indicate that insectivory has little impact on growth of field grown D. rotundifolia. This species is adapted to low nutrient availability and nutrient enhancement reduces growth. Indices of nutrient retention suggest that phosphorus is conserved more than nitrogen and therefore may be an important limiting nutrient. Key words: insectivory, nitrogen, phosphorus, sundew.

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Lee, S. Y., M. C. Maniquiz, J. Y. Choi, J. H. Kang, and L. H. Kim. "Phosphorus mass balance in a surface flow constructed wetland receiving piggery wastewater effluent." Water Science and Technology 66, no. 4 (August 1, 2012): 712–18. http://dx.doi.org/10.2166/wst.2012.231.

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This research was conducted to investigate the phosphorus forms present in water, soil and sediment and to estimate the phosphorus mass balance in a surface flow constructed wetland (CW). Water quality and sediment samples were collected from each cell along the hydrologic path in the CW from October 2008 to December 2010. At the same time, three dominant plant species (e.g. common reed and cattails) were observed through the measurement of the weight, height and phosphorus content. Based on the results, the orthophosphate constituted 24–34% of total phosphorus in water for each cell. The overall average phosphorus removal efficiency of the CW was approximately 38%. The average inflow and outflow phosphorus loads during the monitoring period were 1,167 kg/yr and 408 kg/yr, respectively. The average phosphorus retention rate was 65%, was mainly contributed by the settling of TP into the bottom sediments (30%). The phosphorus uptake of plants was less than 1%. The estimated phosphorus mass balance was effective in predicting the phosphorus retention and release in the CW treating wastewater. Continuous monitoring is underway to support further assessment of the CW system and design.

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50

Fukase, T., M. Shibata, and Y. Miyaji. "Factors Affecting Biological Removal of Phosphorus." Water Science and Technology 17, no. 11-12 (November 1, 1985): 187–98. http://dx.doi.org/10.2166/wst.1985.0232.

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A pilot plant study on biological removal of phosphorus was conducted over fifteen months to obtain optimum operational conditions and evaluate process performance. The pilot plant was composed of an anaerobic zone followed by an aerobic zone, and had a capacity of treating 100 m3 municipal wastewater per day. In the anaerobic zone, BOD loading rates and BOD to MLSS ratios were found to be important factors. In the aerobic zone, on the other hand, the hydraulic retention time had a significant influence on the phosphorus removal efficiency. For successful removal of phosphorus, a shorter hydraulic retention time in the aerobic zone along with appropriate parameters in the anaerobic zone (BOD loading rate ≦ 2 kg-BOD/kg-MLSS day, BOD to MLSS ratio ≦ 0.1 kg-BOD/kg-MLSS) are essential.

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Journal articles on the topic 'Phosphorus retention'

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