Phosphorus Release Rates Research Articles

Nutrient removal from municipal wastewater by activated sludge process

Pilot scale study using an anaerobic‐anoxic‐aerobic activated sludge process for the treatment of nitrogen and phosphorus removal from municipal wastewater in Taiwan was carried out. The BOD, TN and TP removal efficiency of 97.8%, 67.4% and 77.4% were achieved, respectively. Furthermore, effluent TN and TP were decreased to the lever of 8.7 mg/L and 1.13 mg/L, respectively. This showed that the biological treatment process used in this study could remove not only organic matter, but also nitrogen and phosphorus from municipal wastewater. The studies evaluating the rate of nitrification, denitrification, phosphorus release and phosphorus uptake were also performed. During steady state, average results of KN, KDN, KPR and KPU were 0.736 mgNH4‐ N/gMLSS‐hr, 0.524 mgNO3‐N/gMLSS‐hr, 0.174 mgPO4‐P/gMLSS‐hr and 0.243 L/gMLSS‐hr, respectively.

Effect of operating conditions on biological phosphorus removal

Biological phosphorus‐removal processes incorporate a sequence of anaerobic and aerobic contact tanks to select for phosphorus‐storing bacteria and provide them with necessary substrates. Acetate consumption and phosphorus release during anaerobic contacting is followed by phosphorus uptake and storage during aerobic contacting. Bench‐scale studies were conducted in this research to examine the transient effects of longer anaerobic contact time, longer aerobic contact time, and decreased influent chemical oxygen demand (COD) feed concentration on phosphorus release, phosphorus uptake rate, and net phosphorus removal in a sequencing batch reactor (SBR) system enriched for biological phosphorus removal. Batch tests were also performed with sludge from a continuous‐flow anaerobic–anoxic–aerobic biological phosphorus‐removal system to determine the effect of increased anaerobic contact time on phosphorus release and uptake. Both systems were fed a complex synthetic feed, but the SBR system was fed only acetate as its carbon source during the transient effects study. During steady‐state operation of the SBR, the ratio of acetate COD consumed to phosphorus removed averaged 16.5:1, and the molar ratio of acetate used to phosphorus released in the anaerobic period was 0.75:1. In all cases when anaerobic contacting occurred without acetate consumption, phosphorus release rates were lower than normal. Only 40 to 60% of the phosphorus released under acetate‐deficient conditions was taken up under subsequent aeration. Transient effects of longer aeration time and lower influent feed acetate concentration in the SBR experiments resulted in lower phosphorus release and a significant decrease in phosphorus‐removal efficiency in the SBR cycle following the transient change.

Nutrient release from inundated land of a tropical reservoir (Nanhua Reservoir, Taiwan)

Nutrient release from land inundated by creation of a tropical reservoir (Nanhua Reservoir, Taiwan) is investigated. Both the magnitudes of nitrogen and phosphorus which might be released from inundated land are determined on the basis of measurements of biomass and nutrients content of terrestrial vegetation and the nutrients content of topsoil. The fresh biomass of the terrestrial vegetation was estimated at 48600 kg/ha, with an equivalent dry biomass of 15500 kg/ha. After complete decay following submergence, the terrestrial vegetation could potentially contribute 242 kg of nitrogen and 37 kg of phosphorus per hectare. The kinetics of nutrient release from topsoil is determined on a laboratory scale for 80 days, which showed that the phosphorus release rate is averaged at 5.25 mg TP/m 2 /day in anaerobic conditions and 1.34 mg TP/m 2 /day in aerobic conditions, also the nitrogen release rate is averaged at 78.31 mg TKN/m 2 /day in anaerobic condition and 35.71 mg TKN/m 2 /day in aerobic conditions. Based on the actual operation status of Nanhua Reservoir during the initial operation period of 21 months after construction (from August, 1993 to April, 19950 and nutrient release kinetics, the accumulated nutrient loads originating from the topsoil of the inundated land are about 81342 kg of nitrogen and 4701 kg of phosphorus.

Nutrient release from inundated land of a tropical reservoir (nanhua reservoir, Taiwan)

Nutrient release from land inundated by creation of a tropical reservoir (Nanhua Reservoir, Taiwan) is investigated. Both the magnitudes of nitrogen and phosphorus which might be released from inundated land are determined on the basis of measurements of biomass and nutrients content of terrestrial vegetation and the nutrients content of topsoil. The fresh biomass of the terrestrial vegetation was estimated at 48600 kg/ha, with an equivalent dry biomass of 15500 kg/ha. After complete decay following submergence, the terrestrial vegetation could potentially contribute 242 kg of nitrogen and 37 kg of phosphorus per hectare. The kinetics of nutrient release from topsoil is determined on a laboratory scale for 80 days, which showed that the phosphorus release rate is averaged at 5.25 mg TP/m2/day in anaerobic conditions and 1.34 mg TP/m2/day in aerobic conditions, also the nitrogen release rate is averaged at 78.31 mg TKN/m2/day in anaerobic condition and 35.71 mg TKN/m2/day in aerobic conditions. Based on the actual operation status of Nanhua Reservoir during the initial operation period of 21 months after construction (from August, 1993 to April, 19950 and nutrient release kinetics, the accumulated nutrient loads originating from the topsoil of the inundated land are about 81342 kg of nitrogen and 4701 kg of phosphorus.

Understanding and management of cyanobacterial blooms in sub-tropical reservoirs of Queensland, Australia

A three year study of two sub-tropical water supply (potable and irrigation) reservoirs - Baroon Pocket and Leslie - aimed to develop an improved understanding and effective management strategy for the control of low level toxic cyanobacterial ‘blooms’. The two reservoirs appear to be typical of those elsewhere in tropical and sub-tropical Australia, being strongly stratified and monomictic if deep, or polymictic to monomictic (depending on inter-annual climatic variation) if shallow. In both reservoirs, thermal stratification appeared to be the key factor influencing the onset and demise of cyanobacterial blooms. Hypolimnetic deoxygenation was rapid during periods of stratification, and high rates of nitrogen and phosphorus release from bottom sediments occurred during anoxia. External nutrient inputs were dominated by episodic storm in-flows following the passing of (sub)tropical depressions, carrying massive sediment and nutrient loads into the reservoirs. As a consequence of this, and coupled with the high degree of internal nutrient recycling and the low national targets for cyanobacterial control in Australia, we believe that reduction of external nutrient inputs alone, through improved catchment management, may not be sufficient to prevent cyanobacterial blooms. Therefore, more emphasis should be given to ‘in-lake’ control strategies such as destratification, biomanipulation and in situ sediment treatment.

Understanding and management of cyanobacterial blooms in sub-tropical reservoirs of Queensland, Australia

A three year study of two sub-tropical water supply (potable and irrigation) reservoirs - Baroon Pocket and Leslie - aimed to develop an improved understanding and effective management strategy for the control of low level toxic cyanobacterial ‘blooms’. The two reservoirs appear to be typical of those elsewhere in tropical and sub-tropical Australia, being strongly stratified and monomictic if deep, or polymictic to monomictic (depending on inter-annual climatic variation) if shallow. In both reservoirs, thermal stratification appeared to be the key factor influencing the onset and demise of cyanobactenal blooms. Hypolimnetic deoxygenation was rapid during periods of stratification, and high rates of nitrogen and phosphorus release from bottom sediments occurred during anoxia. External nutrient inputs were dominated by episodic storm in-flows following the passing of (sub)tropical depressions, carrying massive sediment and nutrient loads into the reservoirs. As a consequence of this, and coupled with the high degree of internal nutrient recycling and the low national targets for cyanobacterial control in Australia, we believe that reduction of external nutrient inputs alone, through improved catchment management, may not be sufficient to prevent cyanobacterial blooms. Therefore, more emphasis should be given to ‘in-lake’ control strategies such as destratification, biomanipulation and in situ sediment treatment.

Accuracy of diatom-inferred total phosphorus concentrations and the accelerated eutrophication of a lake due to reduced flushing and increased internal loading

The sedimentary record in a small eutrophic lake (White Lough, Northern Ireland) is used to check the accuracy of reconstructing lake total phosphorus concentrations using diatoms and to propose a mechanism for the accelerated eutrophication of certain lakes. The diatom-inferred total phosphorus and sedimentary calcium, magnesium, potassium, iron, manganese, and phosphorus concentrations were measured in a dated sediment core and compared with lake monitoring results for 1978-1983. The values of and trends in diatom-inferred total phosphorus concentration closely follow the monitored concentrations. There was a period of accelerated eutrophication between 1973 and 1979 and the evidence indicates that this was due to reduced hydraulic flushing of the lake during a dry period and a sudden increase in the sediment phosphorus release rate. The results indicate that meso- to eutrophic lakes with hydraulic residence time around a year may be susceptible to this type of accelerated eutrophication.

Phosphorus release by fish in relation to external and internal load in a eutrophic lake

The aim of this study was to compare the rate of phosphorus release from fish with estimates of external and internal load in the eutrophic Finjasjön, Sweden. Phosphorus release from roach and bream, when fed either benthic (Chironomidae) or pelagic (Daphnia) prey, was measured in laboratory tanks. These results were transformed to whole lake conditions by using calculated fish consumption rates of both benthic and pelagic prey based on field data for the community structure, growth rate, and diet of the fish. Phosphorus (P) release from the fish was on the average 0.53 mg P m−2 d−1, which was of the same magnitude (110% of external load) as the external load and 42% of the internal load. Most of the P released from the fish was of pelagic origin, being recycled within the water column. Some 18% of the released P was due to benthic feeding, mainly by large bream, thus representing P translocated from the sediment to the water. This last component of the P release constituted 27% of the external and 10% of the internal load. The P release from fish was in a form directly available to phytoplankton, suggesting that P release from fish may be an important nutrient source for algae.

Temperature Effects on Physiology of Biological Phosphorus Removal

Phosphorus-removing sludge was enriched in an anaerobic-aerobic, acetate-fed, sequencing batch reactor at 20°C. Conversion of relevant compounds for biological phosphorus removal was studied at 5, 10, 20, and 30°C in separate batch tests. The stoichiometry of the anaerobic processes was insensitive to temperature changes. Some effect on aerobic stoichiometry was observed. In contrast, temperature had a strong influence on the kinetics of the processes under anaerobic as well as aerobic conditions. The anaerobic phosphorus-release (or acetate-uptake) rate showed a maximum at 20°C. However, a continuous increase was observed in the interval 5–30°C for the conversion rates under aerobic conditions. Based on these experiments, temperature coefficients for the different reactions were calculated. An overall anaerobic and aerobic temperature coefficient θ was found to be 1.078 (valid in the range 5°C <T< 20°C) and 1.057 (5°C <T< 30°C), respectively.

Interannual variability in spring bloom timing and magnitude in the Rhode River, Maryland, USA:observations and modeling

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 154:27-40 (1997) - doi:10.3354/meps154027 Interannual variability in spring bloom timing and magnitude in the Rhode River, Maryland, USA: observations and modeling Gallegos CL, Jordan TE, Correll DL The long-term average seasonal distribution of chlorophyll concentration in a central reach of the Rhode River estuary (Maryland, USA) has a peak in the spring of about 90 mg m-3. Here we examine interannual variability in chlorophyll and nutrient concentrations in recent years. Years are classified as having an average bloom, extraordinary bloom, or no bloom, and patterns of nutrient concentration are described for each category. To determine processes associated with the different categories of behavior, we performed a generalized sensitivity analysis of a model of nutrient-limited phytoplankton net growth which was previously shown to simulate the chlorophyll concentration and the observed pattern of shift from P to N limitation in an average year. Model parameters controlling the delivery of N and P by the environment and the biological utilization of nutrients by the phytoplankton were drawn from random distributions based on literature reports or, where available, data from the Rhode River. Model output for each parameter set was classified according to which, if any, of the classes of bloom it exhibited. Environmental processes most responsible for the variability in predicted spring blooms were the rate of phosphorus release from the sediment, the timing of nitrate depletion at the seaward boundary, and the maximal nitrate concentration at the boundary. Simulation of bloom failure was most strongly associated with low rates of phosphorus release from the sediment. Phytoplankton physiological parameters most responsible for variability in categories of behavior were the nitrogen:chlorophyll conversion factor, and the maximum internal storage capacity for phosphorus. Blooms of extraordinary magnitude were associated with low nitrogen:chlorophyll ratios and high storage capacity for phosphorus. Results help identify key processes and parameters in need of further understanding as well as possible points for managerial intervention. Phytoplankton · Spring bloom · Estuarine · Nitrogen · Phosphorus Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 154. Publication date: July 31, 1997 Print ISSN:0171-8630; Online ISSN:1616-1599 Copyright © 1997 Inter-Research.

Phosphate Release and Uptake by Pure Cultures of Acinetobacter sp.: Effect of the Volatile Fatty Acids Concentration

Phosphorus release and uptake by pure cultures of Acinetobacter strains were investigated under anaerobic and aerobic conditions respectively. Tests were performed to study the relationship between phosphorus release-storage reaction and behavior of extracellular organic substrates: acetic, propionic, and butyric acids have been used at four concentrations (50, 100, 500, and 1000 mg &middot; L-1) in the anaerobic step of biological phosphorus removal. The results obtained depend on the strain and the volatile fatty acid (VFA) used. Phosphorus released under anaerobic condition was not always related to the amount of VFA or phosphorus consumed. Phosphorus uptake (P-uptake) in the aerobic step was found to be independent of phosphorus release rates. The best phosphorus uptake rates were obtained by Acinetobacter lwoffi ATCC21130 and Acinetobacter calcoaceticus Genoespecie SUCT-5 with butyric acid as carbon source.

Kinetic competition between phosphorus release and denitrification on sludge under anoxic condition

The kinetic behaviors of simultaneous phosphorus release and denitrification on sludge were investigated under anoxic condition. A phosphorus enriched sludge produced from Anaerobic-Anoxic-Oxic (AnAO) process under various SRT (5, 10 and 15 days) operation conditions was carried out in a series of batch tests. Experimental results indicated that the available organic substrate determined the kinetic behaviors of phosphorus release/uptake and denitrification. The simultaneous phosphorus release and denitrification demonstrated a kinetic competition under anoxic conditions in the presence of an available organic substrate. When the substrate was abundant, sludge was under “releasable-phosphorus-limited” condition; phosphorus release rate decreased slightly by nitrate inhibition. However, nitrate significantly inhibited phosphorus release when sludge was under “initial-substrate-limited” condition. Moreover, the sludge's phosphorus contents (as created by different SRT processes) dominated the kinetics of competition between phosphorus release and denitrification. The sludge with a high phosphorus content had a higher phosphorus release rate in accordance with a lower denitrification rate. Additionally, the substrate sequestrated rate markedly increased under the condition of simultaneous phosphorus release and denitrification. Finally, a preliminary metabolism model of denitrifying phosphorus removal bacteria was proposed, and found to be capable of adequately accounting for simultaneous phosphorus release and denitrification under anoxic conditions.

Intraspecific stoichiometric variability and the ratio of nitrogen to phosphorus resupplied by zooplankton

1. An in situ experiment was carried out in a high‐mountain oligotrophic lake (La Caldera) to quantify the specific release rates of ammonium and phosphorus in different phases of the seasonal succession of plankton. The zooplankton community was dominated by the calanoid copepod Mixodiaptomus laciniatus.2. The rates of release of N and P (from non‐detectable to 3.58 μg N mg–1 DW h–1 and from 0.26 to 2.29 μg P mg–1 DW h–1, respectively) and the N : P released ratio (not detectable to 4.77) fell within the range typical of oligotrophic lakes dominated by copepodite assemblages.3. The values of the zooplankton N : P ratio (5 : 1 to 10 : 1 by weight) were lower than those established for other species of calanoids, and followed a well‐established pattern of seasonal variation from year to year with higher values after ice thaw and lower values as individual size increased (ontogenetic development).4. The elemental composition of the zooplankton depended on individual size, while the released N : P ratio was inversely related to the N : P ratio of the food. This pattern conforms to the predictions of the homeostasis theory of Sterner (1990).5. A feedback regulation was established between the stoichiometric composition of the zooplankton, their food and the released N : P ratio that can help explain changes in pelagic community structure during the ice‐free period.

A laboratory study of sediment phosphorus flux in two tropical reservoirs

The prevailing levels of dissolved oxygen, pH and temperature in a sediment-water interface largely influence the sediment nutrient flux in waterbodies. The main objective of this study is to appraise the interaction between the aquatic sediment in two tropical reservoirs and the overlying water in simulated laboratory conditions. In actuality, these two reservoirs were subjected to highly varying nutrient inputs. Sediment and water samples were collected from both the reservoirs for laboratory simulation tests. Perspex columns were used as reaction chambers to study the effect of dissolved oxygen levels and pH values on sediment nutrient flux over a period of 60 days under controlled conditions. In the oxic chambers, DO levels were maintained within 7.5 mg/L to 7.7 mg/L whereas DO levels of less than 1 mg/L were maintained in anoxic chambers using argon gas. The concentrations of orthophosphate and total phosphorus in the overlying waters increased significantly in the anoxic chambers for both reservoirs though release rates in Kranji Reservoir sediments were 1.5 to 19.5 times greater than those in MacRitchie Reservoir. The highest total phosphorus release rates prevailed in Kranji and were 13.5 to 14.8 mg/m2.d at pH values of 5 and 9, respectively. These release rates are marginally lower than those reported in other in situ experiments. It can be concluded that the DO and pH are important in controlling the sediment nutrient flux, particularly in anaerobic or highly alkaline conditions, and hence will influence considerably the quality of the overlying waters in tropical reservoirs.

Release Rates of Phosphorus, Ammonium, and Potassium in Clinoptilolite‐Phosphate Rock Systems

AbstractControlled release of P, NH4, and K can be accomplished in synthetic soils through dissolution and cation‐exchange reactions by phosphate rock (PR) and the zeolite mineral, clinoptilolite (Cp). The power‐function equation has previously been found to adequately describe transport kinetics of the nutrient release process. Research was conducted to evaluate factors affecting P, NH4, and K release rates in Cp‐PR systems. Data was collected using a continuous‐flow thin‐disk technique. Results were evaluated with the power‐function equation. Materials included a Texas Cp and North Carolina and Tennessee PRs. Variables examined included the Cp/PR ratio, the mole fraction of NH4 and K on the Cp, and the type of PR. The power‐function model indicated that initial release rates and cumulative nutrient release in Cp‐PR mixtures were increased by using a higher Cp‐PR ratio and by using a more reactive PR. Nutrient release rates were also affected by changes in the proportion of NH4 and K occupying Cp exchange sites and reflected ion‐selectivity characteristics of Cp. The results indicate that Cp and PR may be used to obtain a controlled release of NH4, P, and K in a synthetic soil.

The kinetic behaviors of simultaneous phosphorus release and denitrification on sludge for BNR processes

Abstract In this study, we investigated the kinetic behaviors of phosphorus release and denitrification on sludge for two biological nutrient removal (BNR) processes, i.e., suspension growth process (A2O) and combined suspension‐biofilm growth process (TNCU) under anoxic condition. The readily biodegradable substrate and nitrate loadings, 20–180 mg HAc‐COD/g MLSS and 4–25 mg NO3‐N/g MLSS respectively, are controlled in a batch reactor for phosphorus release and denitrification of sludge taken from A2O and TNCU processes under various SRT (5, 10 and 15 days) operating conditions. Experimental results indicated that the occurrence of simultaneous phosphorus release and denitrification is a kinetic competition mode under anoxic condition in the presence of a readily biodegradable substrate. Moreover, the available substrate in bulk solution determined the kinetic behaviors of phosphorus release and denitrification. To prevent nitrate inhibition, the sludge is exposed to a C/N ratio higher than 6.1 for phosphorus release. The sludge's phosphorus content (as created by different SRT processes) and initial nitrate loading dominated the kinetics of phosphorus release and denitrification, respectivley. Moreover, the sludge of suspension gorwth process demonstrated a higher phosphorus release potential than the combined suspension‐biofilm growth process. However, the nitrate inhibition is significant for A2O sludge also. Based on proposed phosphorus release rate equation, the rate constant would be reduced by denitrification about 31–67% and 20–45% for A2O and TNCU processes, respectively.

A laboratory study of sediment phosphorus flux in two tropical reservoirs

The prevailing levels of dissolved oxygen, pH and temperature in a sediment-water interface largely influence the sediment nutrient flux in waterbodies. The main objective of this study is to appraise the interaction between the aquatic sediment in two tropical reservoirs and the overlying water in simulated laboratory conditions. In actuality, these two reservoirs were subjected to highly varying nutrient inputs. Sediment and water samples were collected from both the reservoirs for laboratory simulation tests. Perspex columns were used as reaction chambers to study the effect of dissolved oxygen levels and pH values on sediment nutrient flux over a period of 60 days under controlled conditions. In the oxic chambers, DO levels were maintained within 7.5 mg/L to 7.7 mg/L whereas DO levels of less than 1 mg/L were maintained in anoxic chambers using argon gas. The concentrations of orthophosphate and total phosphorus in the overlying waters increased significantly in the anoxic chambers for both reservoirs though release rates in Kranji Reservoir sediments were 1.5 to 19.5 times greater than those in MacRitchie Reservoir. The highest total phosphorus release rates prevailed in Kranji and were 13.5 to 14.8 mg/m2.d at pH values of 5 and 9, respectively. These release rates are marginally lower than those reported in other in situ experiments. It can be concluded that the DO and pH are important in controlling the sediment nutrient flux, particularly in anaerobic or highly alkaline conditions, and hence will influence considerably the quality of the overlying waters in tropical reservoirs.

Internal Phosphorus Loading in Shallow Lakes: Importance and Control

ABSTRACT Decreasing the algal biomass and increasing transparency in shallow, unstratified lakes is usually more difficult than for deep, stratified lakes. Eutrophic unstratified lakes (or shallow, stratified lakes susceptible to metalimnion erosion) have typically responded slowly to reduced external nutrient loading, usually because of longevity of internal loading. That is because sediment-released nutrients (especially phosphorus) readily enter the trophogenic zone of shallow lakes during the growing season and result in high lake concentrations. In stratified lakes, metalimnia may serve as barriers to phosphorus transport into the trophogenic zone. Although the whole water column in shallow lakes is usually aerobic, several mechanisms can combine to produce relatively high sediment phosphorus release rates in these lakes. These include: 1) wind resuspension and bioturbation, combined with high pH or low Fe/P ratio that maintains high P solubility, 2) periodic anoxia and reducing conditions promoted by calm, warm weather, and 3) macrophyte senescence. Attempts to reduce algal biomass by controlling internal phosphorus loading have often been effective.

Laboratory Prediction of Phosphorus Release from Deciduous Leaves to Urban Runoff

Abstract In urban centres, leaves are customarily gathered and temporarily stored in large roadside piles prior to their transport to disposal sites. To simulate the release of total phosphorus to urban runoff, birch and trembling aspen leaves were leached with distilled water in laboratory flasks. There was no difference in rate of total phosphorus release between oven-dried and non-dried leaves. An empirical equation developed from these data and knowledge of the litterfall rates for southern Canada indicated that leaves yielded from 11 to 45 mg TP m−2 of forested watershed. This amount represents up to 5% of the total export of total phosphorus from urban catchments and has the potential to exacerbate eutrophication of municipal waters if leaf pickup is not promptly enforced.

Estimation of phosphorus release rates from natural zooplankton communities feeding on planktonic algae and bacteria

Phosphorus release rates from Daphnia galeata, the dominant metazoan, were estimated in eutrophic Lake Nesjøvatn during summer by applying our previously published mass balance model. For both juveniles (2.0 µg C ind.−1) and adults (6.6 µg C ind.−1), three different estimates of P release were made by two different parametrizations and by considering the importance of ingestion of detrital particles. As a basis for estimates of P release, clearance rates of algae and bacteria were determined as well as a thorough characterization of the food compartments.The specific release rate of P varied between 0.16 and 1.18 µg P mg C h−1 for juveniles and between 0.06 and 0.96 for adults, independent of estimate. These release rates are considerably lower than those obtained by previously published models. Most of the observed variation was due to variation in the P content of the food, thus emphasizing the importance of including this variable in studies of P release from zooplankton. Calculations of rates of population P release suggest that D. galeata contributed &lt;⅓ of the P requirements of algae and bacteria.