Biological Phosphate Removal Research Articles

Biological Application of Micro‐Electro Mechanical Systems Microelectrode Array Sensors for Direct Measurement of Phosphate in the Enhanced Biological Phosphorous Removal Process

The determination of phosphate has been of great importance in the fields of clinical, environmental, and horticultural analysis for over three decades. New cobalt-based micro-electro mechanical systems (MEMS) microelectrode array (MEA) sensors for direct measurement of phosphate in small environmental samples, such as microbial aggregates, has been introduced and applied here for in situ measurement of phosphate within activated sludge flocs in the enhanced biological phosphorus removal process. The MEMS technologies offer the advantages of accurate fabrication methods, reduced complexity of the fabrication process, mass production, low cost, and increased reliability. Well-defined phosphate profiles across the flocs were observed under anaerobic conditions, during which, phosphate was released from the flocs, using the MEMS MEA sensor. The microprofiles were compared with the microprofiles measured using conventional phosphate microelectrodes. The developed MEMS MEA sensors were useful tools for the in situ measurement of phosphate in small aggregates.

The contribution of ‘omic’-based approaches to the study of enhanced biological phosphorus removal microbiology

The role that microorganisms play in the biological removal of phosphate from wastewater streams has received sustained interest since its initial observation over 30 years ago. Recent advances in 'omic'-based approaches have greatly advanced our knowledge in this field and facilitated a refinement of existing enhanced biological phosphate removal (EBPR) models, which were primarily based on culture-dependent approaches that had predominantly been used to investigate the process. This minireview will focus on the recent advances made in our overall understanding of the EBPR process resulting from the use of 'omic'-based methodologies.

Dynamic parameter estimation to calibrate the activated sludge model for an enhanced biological phosphate removal process

A parameter calibration of activated sludge models (ASMs) was performed to predict effluent chemical oxygen demand (COD), total nitrogen (TN), total phosphate (TP) and total suspended solid (TSS) concentrations of the enhanced biological phosphate removal process. Such calibration is an essential process for simulating the behavior of real-world wastewater treatment processes properly. Six different simulations were attempted to develop a reliable calibration method using two different parameter estimation methods for three objective functions. For the parameter estimation method, dynamic parameter estimation (DPE) and static parameter estimation (SPE) were investigated. The objective functions were based on the effluent quality (EQ) index of benchmark simulation and the effluent quality standards (EQS) in Korea. When using the same parameter estimation method, the predicted errors with the EQS-based objective functions could be decreased by approximately 20% over EQ index-based functions for TSS. When us...

生物学的リン除去活性の変動過程におけるグリコーゲン蓄積細菌群の酢酸摂取速度の急激な上昇

An A/O SBR fed with acetate was operated at pH 7.0 after the inoculation of activated sludge capable of enhanced biological phosphate removal (EBPR). Glycogen-accumulating organisms (GAOs) were predominant in acetate uptake on the 19th day of operation. The operational pH was then increased to 8.2. Accordingly, the acetate uptake activity of GAOs gradually decreased as intended, whereas phosphate release activity improved. To estimate acetate uptake rate with addition of acetate more than that in the A/O SBR operation, an anaerobic batch test was conducted. Higher amounts of acetate added led to significantly high acetate uptake rates that were not consistent with phosphate release rates only when the acetate uptake activity of GAOs was relatively low in the A/O SBR operation. In other words, an acetate concentration higher than the usual influent concentration probably stimulates the acetate uptake activity of GAOs. These results suggest that a rapid increase in the acetate uptake rate of GAOs affects the sudden deterioration of EBPR.

How Biological Phosphorous Removal is Inhibited by Collection System Corrosion and Odor Control Practices

How Biological Phosphorous Removal is Inhibited by Collection System Corrosion and Odor Control Practices

Biological Application of MEMS Microelectrode Sensors for Direct Measurement of Phosphate in the Enhanced Biological Phosphorous Removal Process

Biological Application of MEMS Microelectrode Sensors for Direct Measurement of Phosphate in the Enhanced Biological Phosphorous Removal Process

Biological phosphate removal by model based fed-batch cultivation of Acinetobacter calcoaceticus

A simpler phosphate removal process has been proposed involving only aerobic cultivation of Acinetobacter calcoaceticus in a fed-batch mode of treatment. Batch cultivation of A. calcoaceticus was conducted under statistically optimized culture conditions in order to study the kinetics of growth and phosphate uptake. Studies with respect to carbon, nitrogen and phosphate were performed to quantify their inhibitory effect on specific growth rate (if any). Using kinetics/inhibition data, a mathematical model was proposed. The batch model was extrapolated for fed-batch cultivation by incorporating the dilution terms in the model equations so as to predict, suitable nutrient feeding strategy for better phosphate removal. According to the developed feed-strategy, the bioreactor was operated in batch mode for 4 h, after which model based predetermined fresh nutrient feeding (sodium acetate 5.0 g/l) at 2.25 ml/min was started. Model predictions indicated that after 7 h of cultivation process phosphate would be totally consumed. Upon implementation of this model based fed-batch cultivation strategy a biomass accumulation of 4.02 g/l was obtained experimentally against 3.88 g/l concentration predicted by model after 7 h with a residual phosphate concentration of 0.01 g/l. An improvement to 94% phosphate removal efficiency (initial loading 0.175 g/l) in only 7 h was observed in fed-batch cultivation as opposed to 78% (initial loading 0.175 g/l) in 11 h for batch cultivation.

On-line Diagnosis System with Learning Bayesian Networks for fsEBPR

Nowadays, due to development of automatic control devices and various sensors, one operator can freely handle several remote plants and processes. Automatic diagnosis and warning systems have been adopted in various fields, in order to prepare an operator’s absence for patrolling plants. In this paper, a Bayesian networks based on-line diagnosis system is proposed for a wastewater treatment process. Especially, the suggested system is included learning structure, which can continuosly update conditional probabilities in the networks. To evaluate performance of proposed model, we made a lab-scale five-stage step-feed enhanced biological phosphorous removal process plant and applied on-line diagnosis system to this plant in the summer.

Ecology of the Microbial Community Removing Phosphate from Wastewater under Continuously Aerobic Conditions in a Sequencing Batch Reactor

All activated sludge systems for removing phosphate microbiologically are configured so the biomass is cycled continuously through alternating anaerobic and aerobic zones. This paper describes a novel aerobic process capable of decreasing the amount of phosphate from 10 to 12 mg P liter(-1) to less than 0.1 mg P liter(-1) (when expressed as phosphorus) over an extended period from two wastewaters with low chemical oxygen demand. One wastewater was synthetic, and the other was a clarified effluent from a conventional activated sludge system. Unlike anaerobic/aerobic enhanced biological phosphate removal (EBPR) processes where the organic substrates and the phosphate are supplied simultaneously to the biomass under anaerobic conditions, in this aerobic process, the addition of acetate, which begins the feed stage, is temporally separated from the addition of phosphate, which begins the famine stage. Conditions for establishing this process in a sequencing batch reactor are detailed, together with a description of the changes in poly-beta-hydroxyalkanoate (PHA) and poly(P) levels in the biomass occurring under the feed and famine regimes, which closely resemble those reported in anaerobic/aerobic EBPR processes. Profiles obtained with denaturing gradient gel electrophoresis were very similar for communities fed both wastewaters, and once established, these communities remained stable over prolonged periods of time. 16S rRNA-based clone libraries generated from the two communities were also very similar. Fluorescence in situ hybridization (FISH)/microautoradiography and histochemical staining revealed that "Candidatus Accumulibacter phosphatis" bacteria were the dominant poly(P)-accumulating organisms (PAO) in both communities, with the phenotype expected for PAO. FISH also identified large numbers of betaproteobacterial Dechloromonas and alphaproteobacterial tetrad-forming organisms related to Defluviicoccus in both communities, but while these organisms assimilated acetate and contained intracellular PHA during the feed stages, they never accumulated poly(P) during the cycles, consistent with the phenotype of glycogen-accumulating organisms.

Practical wastewater treatment

1 Introduction. Introduction. Water Composition. Pure Water. Salts and Ions in Water. Principal Contaminants and Ions in Water and Measurement Methods. Sources of Water. Water Quality. Water Quality Regulations-Legal Structure. Rules and Regulations for Water Quality Control. Applications. Sample Problem. Solution. Drinking Water Quality Standards: USA and International Standards. 2 Effects of Pollution. Effluent Toxicity Testing. Oxygen Depletion-Biochemical Oxygen Demand. Oxygen Uptake in a Stream-The Oxygen Sag Equation. Biology of Polluted Water. 3 Flow Measurement. Review of Open Channel Hydraulics. Determining Normal and Gradually Varied Flows. Types of Flowmeters. Weir Plates. 4 Sampling and Statistical Considerations. Errors in Process Measurements. Statistical Distributions. Lognormal Distributions. Weibull Distributions. Probable Error. Repeat Measurements. Sampling. 5 Important Concepts from Aquatic Chemistry. Common Ion Species. Most Important Chemicals in the Water Environment. Carbonate Chemistry. Chemical Water Softening. Excess Lime Process. Metals Removal by Precipitation. Heavy Metals. Chromium Reduction and Metals Precipitation. Silicates in Treatment Systems. Nitrogen. Sulfur. Phosphorous. 6 Elements of Biological Treatment. Introduction. BOD and COD Solids. Suspended Solids. Biological Growth Equation. Biological Growth & the Monod Equation. Principles of Biological Treatment Systems. Activated Sludge & Its Varations. Biological Treatment of Difficult Wastes. Modeling the Biological Process. Steady. JASS. Scilab/SeTS. Available Commercial Modeling Tools. Modeling Guidance. The IWA Models for Activated Sludge. 7 Precipitation and Sedimentation. Theory of Sedimentation. Clarifiers and Their Design. Lamellas and Specialty Devices. 8 Filtration Theory and Practice. Depth Filters Design: Theory and Practice. Filtration Hydraulics. Hydraulics of Filter Washing. Skin Filters. Filter Elements and Design. 9 Disinfection. General. Rate of Kill-Disinfection Parameters. Status of U.S. Drinking Water. Chlorine. Ozone. Ultraviolet Light. Other Disinfecting Compounds. 10 Nitrogen Removal. Nitrogen Chemistry and Forms. Ammonia Toxicity and Nitrogen Loading. Nitrate. Nitrogen Removals. Mixed Media and Attached Growth Systems. Conclusions. 11 Phosphorous Removal. General. Biological Phosphorous Removal. Chemical Phosphorous Removal. 12 Anaerobic Treatment. Basic Anaerobic Processes. Anaerobic Pretreatment. Sludge Digestion. Sludge Treatment. Anaerobic Digester Model ADM1. 13 Micro/Ultrafiltration. Introduction to Membrane Separations and Microfiltration. Design Values. Process Selection. 14 Reverse Osmosis. Introduction. Mass Transfer Theory. Membrane Selection. Membrane Materials. Membrane Configurations. RO Design Considerations. Design Parameters. 15 Carbon Adsorption. Breakthrough Curves. The Freundlich and the Langmuir Equations. Carbon Adsorption Physical Coefficients and Economics. PACTTM Process. 16 Ion Exchange. Introduction. Resins. Selectivity. Selectivity Coefficient. Design Considerations. 17 Dissolved Air Flotation and Techniques. Design Basics for DAF. Operating Parameters. Electroflotation. Electrocoagulation. 18 Coagulation, Flocculation, and Chemical Treatment. Introduction. Flocculation and Mixing. Practice. Modeling. 19 Waste Topics. Oily Wastewaters. Blood and Protein. Milk Wastes. Refinery Wastes. Metal Plating Wastes. Starch Wastes. Phenols and Chemical Plant Wastes. Small Waste Flows. Final Thoughts. Index.

Characteristics of anoxic phosphors removal in sequence batch reactor

The characteristics of anaerobic phosphorus release and anoxic phosphorus uptake were investigated in sequencing batch reactors using denitrifying phosphorus removing bacteria (DPB) sludge. The lab-scale experiments were accomplished under conditions of various nitrite concentrations (5.5, 9.5, and 15 mg/L) and mixed liquor suspended solids (MLSS) (1844, 3231, and 6730 mg/L). The results obtained confirmed that nitrite, MLSS, and pH were key factors, which had a significant impact on anaerobic phosphorus release and anoxic phosphorus uptake in the biological phosphorous removal process. The nitrites were able to successfully act as electron acceptors for phosphorous uptake at a limited concentration between 5.5 and 9.5 mg/L. The denitrification and dephosphorous were inhibited when the nitrite concentration reached 15 mg/L. This observation indicated that the nitrite would not inhibit phosphorus uptake before it exceeded a threshold concentration. It was assumed that an increase of MLSS concentration from 1844 mg/L to 6730 mg/L led to the increase of denitrification and anoxic P-uptake rate. On the contrary, the average P-uptake/N denitrifying reduced from 2.10 to 1.57 mg PO 4 3−-P/mg NO 3 −-N. Therefore, it could be concluded that increasing MLSS of the DEPHANOX system might shorten the reaction time of phosphorus release and anoxic phosphorus uptake. However, excessive MLSS might reduce the specific denitrifying rate. Meanwhile, a rapid pH increase occurred at the beginning of the anoxic conditions as a result of denitrification and anoxic phosphate uptake. Anaerobic P release rate increased with an increase in pH. Moreover, when pH exceeded a relatively high value of 8.0, the dissolved P concentration decreased in the liquid phase, because of chemical precipitation. This observation suggested that pH should be strictly controlled below 8.0 to avoid chemical precipitation if the biological denitrifying phosphorus removal capability is to be studied accurately.

Effect of initial pH control on enhanced biological phosphorus removal from wastewater containing acetic and propionic acids

In the literature most of the studies on the effect of pH on enhanced biological phosphorous removal were conducted with the acetate wastewater, and the pH was controlled during the entire anaerobic and aerobic stages. This paper investigated the influence of anaerobic initial pH control, which will be more practical than the entire process pH control strategy, on enhanced biological phosphorus removal from wastewater containing acetic and propionic acids. Typical pH profile showed that both the initial alkaline and acidic pH tended to neutralize due to the consumption of short-chain fatty acid (SCFA) and intracellular pH regulation by polyphosphate accumulating organisms (PAOs). It was observed that the glycogen degradation and polyhydroxyalkanoates (PHA) accumulation decreased with increasing initial pH, which disagreed with previous reports. In the literature the metabolisms of both glycogen and PHA by PAOs in the acetate wastewater were independent of pH. An anaerobic mechanism model was proposed to explain the intra- and extra-cellular pH buffer nature of PAOs, and to address the reasons for increased polyphosphate degradation and decreased PHA synthesis and glycogen degradation at higher pH. The optimal initial pH for higher soluble ortho-phosphorus (SOP) removal efficiency should be controlled between 6.4 and 7.2. This pH control strategy will be easier to use in practice of wastewater treatment plant.

Advanced sludge reduction and phosphorous removal process

An advanced sludge reduction process, i. e. sludge reduction and phosphorous removal process, was developed. The results show that excellent sludge reduction and biological phosphorous removal can be achieved perfectly in this system. When chemical oxygen demand ρ (COD) is 332 – 420 mg/L, concentration of ammonia ρ(NH3-N) is 30 – 40 mg/L and concentration of total phosphorous ρ(TP) is 6.0 – 9.0 mg/L in influent, the system still ensures ρ(COD)<23 mg/L, ρ(NH3-N)<3.2 mg/L and ρ(TP)<0.72 mg/L in effluent. Besides, when the concentration of dissolved oxygen ρ(DO) is around 1.0 mg/L, sludge production is less than 0.140 g with the consumption of 1 g COD, and the phosphorous removal exceeds 91%. Also, 48.4% of total nitrogen is removed by simultaneous nitrification and denitrification.

Biological phosphate removal using a degradable carbon source produced by hydrothermal treatment of excess sludge

Abstract - The possibility of reusing excess sludge treated by hydrothermal reaction for the purpose of improving the efficiency of the enhanced biological phosphate removal (EBPR) process was investigated. Excess sludge from a fish-processing industry located in Japan was treated in high-temperature and high-pressure water, at a reaction temperature ranging from 200 to 400 o C, a pressure of 1.8 to 30MPa and a constant reaction time of 7 min. For the conditions tested, the results showed that when the reaction temperature was increased the content of readily biodegradable substrate in the total COD Cr increased. In addition, the amount of some volatile fatty acids (VFAs) produced by the hydrothermal reaction increased as reaction temperature increased. From the phosphate release tests under anaerobic conditions, it was possible to demonstrate that not only the VFAs, but also the readily and slowly biodegradable substrates are used as potential carbon source by the phosphate-accumulating organisms (PAOs).

Use of activate sludge model no. 3 and Bio-P module for simulating five-stage step-feed enhanced biological phosphorous removal process

The ASM3 with EAWAG Bio-P Module (ASM3+P) was used for simulating a five-stage step-feed Enhanced Biological Phosphorous Removal (fsEBPR) process and its applicability was compared with the ASM2d. The fsEBPR process was predicted to achieve effective nitrogen and phosphorus removal from the wastewater even with low C/N and C/P ratios without additional carbon sources. Application of the ASM3+P on this configuration will be an ample chance for expanding the new models in the activated sludge process. Sensitivity analysis and parameter estimation were conducted with the ASM2d and the ASM3+P prior to model application so that calibration of the models could focus only on the sensitive parameters. The ASM2d was less successful for predicting the process behavior. Moreover, the ASM2d required 6 times more computation time than that for the AMS3+P due to its decay-regeneration model structure. To confirm the applicability of parameters determined from the pilot-scale reactor operating results, those were tested on the field data without further correction. Only the ASM3+P successfully predicted nitrogen and phosphate variations in the full-scale plants. Overall examination of simulation results using the pilot and full-scale data has led to the conclusion that the ASM3+P is better than the ASM2d for simulating fsEBPR processes.

Which are the polyphosphate accumulating organisms in full-scale activated sludge enhanced biological phosphate removal systems in Australia?

To see if the compositions of the microbial communities in full scale enhanced biological phosphorus removal activated sludge systems were the same as those from laboratory scale sequencing batch reactors fed a synthetic sewage. Biomass samples taken from nine full scale enhanced biological phosphate removal (EBPR) activated sludge plants in the eastern states of Australia were analysed for their populations of polyphosphate (polyP)-accumulating organisms (PAO) using semi-quantitative fluorescence in situ hybridization (FISH) in combination with DAPI (4'-6-diamidino-2-phenylindole) staining for polyP. Very few betaproteobacterial Rhodocyclus related organisms could be detected by FISH in most of the plants examined, and even where present, not all these cells even within a single cluster, stained positively for polyP with DAPI. In some plants in samples from aerobic reactors the Actinobacteria dominated populations containing polyP. The PAO populations in full-scale EBPR systems often differ to those seen in laboratory scale reactors fed artificial sewage, and Rhodocyclus related organisms, dominating these latter communities may not be as important in full-scale systems. Instead Actinobacteria may be the major PAO. These findings illustrate how little is still known about the microbial ecology of EBPR processes and that more emphasis should now be placed on analysis of full-scale plants if microbiological methods are to be applied to monitoring their performances.

Pilot-Scale Evaluation of the Application of Low pH-Inducible Polyphosphate Accumulation to the Biological Removal of Phosphate from Wastewaters

To investigate the possible biotechnological application of the phenomenon of low pH-inducible phosphate uptake and polyphosphate accumulation, previously reported using pure microbial cultures and under laboratory conditions, a 2000 L activated sludge pilot plant was constructed at a municipal sewage treatment works. When operated as a single-stage reactor this removed more than 60% of influent phosphate from primary settled sewage at a pH of 6.0, as opposed to approximately 30% at the typical operational pH for the works of 7.0-7.3-yet without any deleterious effect on other treatment parameters. At these pH values the phosphorus content of the sludge was, respectively, 4.2% and 2.0%. At pH 6.0 some 33.9% of sludge microbial cells were observed to contain polyphosphate inclusions; the corresponding value at pH 7.0 was 18.7%. Such a process may serve as a prototype for the development of alternative biological and chemical options for phosphate removal from wastewaters.

Simultaneous Nitrogen and Phosphorus Removal in a Continuously Fed and Aerated Membrane Bioreactor

This research demonstrated the feasibility of simultaneous biological nitrogen and phosphorous removal in a single tank membrane bioreactor without cycling of air and/or feed through operation at a low dissolved oxygen (DO) and a high biomass concentration. Chemical oxygen demand removal efficiency was more than 98% and total nitrogen removal efficiency was 55%. Seventy-five percent of the total nitrogen removal was through simultaneous nitrification–denitrification (SND) and 25% through assimilation into the biomass. Interestingly, more than 98% phosphorous was removed and microbiological analysis showed the presence of polyphosphate-accumulating organisms in the activated sludge. The operating mixed-liquor suspended solids was between 16 and 23 g∕L . The optimum DO was found to be 0.7–0.8 mg∕L .

Biological phosphate removal by model based continuous cultivation of Acinetobacter calcoaceticus

Batch cultivation of Acinetobacter calcoaceticus was carried out under statistically optimized culture conditions in order to study the kinetics of growth and phosphate uptake. It featured a biomass accumulation of 4.08 g L −1 with a consumption of 0.14 g L −1 phosphate (from initial phosphate concentration of 0.18 g L −1) in 11 h. Inhibition studies with respect to carbon, nitrogen and phosphate were also performed to quantify their limiting and/or inhibitory effect on specific growth rate. Using above kinetics/inhibition data, mathematical model equations were proposed and then model parameters were identified for batch cultivation of A. calcoaceticus. The batch model was extrapolated for continuous cultivation so as to predict, steady state concentrations of process variables and identify suitable nutrient feeding strategies for even better/quicker phosphate removal. In order to make a comprehensive study of the effect of dilution rate on culture growth and phosphate uptake, different dilution rates of 0.04, 0.09, 0.13, 0.19, 0.3, 0.4 h −1 were utilized in the model to predict transient and steady state data, which were experimentally verified to establish the validity of the model. It was observed that as the dilution rate increased, the steady state biomass concentration gradually decreased and residual substrate concentration increased, indicating the applicability of well-known Monod type growth pattern. Best biomass accumulation (3.5 g L −1) and phosphate uptake (∼76%) was obtained at D = 0.09 h −1 experimentally. Studies in a continuous stirred tank reactor (CSTR) demonstrated the feasibility to achieve faster phosphate removal without inherently slow anaerobic phase involvement.

Effects of Reduced Return Activated Sludge Flows and Volume on Anaerobic Zone Performance for a Septic Wastewater Biological Phosphorus Removal System

Enhanced biological phosphorous removal (EBPR) performance was found to be adequate with reduced return-activated sludge (RAS) flows (50% of available RAS) to the anaerobic tank and smaller-than-typical anaerobic zone volume (1.08 hours hydraulic retention time [HRT]). Three identical parallel biological nutrient removal pilot plants were fed with strong, highly fermented (160 mg/L volatile fatty acids [VFAs]), domestic and industrial wastewater from a full-scale wastewater treatment facility. The pilot plants were operated at 100, 50, 40, and 25% RAS (percent of available RAS) flows to the anaerobic tank, with the remaining RAS to the anoxic tank. In addition, varying anaerobic HRT (1.08 and 1.5 hours) and increased hydraulic loading (35% increase) were examined. The study was divided into four phases, and the effect of these process variations on EBPR were studied by having one different variable between two identical systems. The most significant conclusion was that returning part of the RAS to the anaerobic zone did not decrease EBPR performance; instead, it changed the location of phosphorous release and uptake. Bringing less RAS to the anaerobic and more to the anoxic tank decreased anaerobic phosphorus release and increased anoxic phosphorus release (or decreased anoxic phosphorus uptake). Equally important is that, with VFA-rich influent wastewater, excessive anaerobic volume was shown to hurt overall phosphorus removal, even when it resulted in increased anaerobic phosphorus release.