Extended Aeration System Research Articles

Economic implications of optimal operating conditions in a full-scale continuous intermittent cycle extended aeration system (ICEAS)

Economic implications of optimal operating conditions in a full-scale continuous intermittent cycle extended aeration system (ICEAS)

Simulation study of a practical approach to enhance cadmium removal via biological treatment by controlling the concentration of MLSS

The fate of cadmium at the Muharram Aisha wastewater treatment plant in Karbala governorate, Iraq was studied using the TOXCHEM model. Cadmium, a known carcinogen, and is considered one of the most dangerous heavy metals and high concentrations, greater than permissible limits, were found in the treated wastewater. The plant operates using an activated sludge system and this was modeled via TOXCHEM with a sensitivity analysis carried out on the extended aeration system. Prior to analysis, the model was calibrated and validated for cadmium, with the adjustments leading to a mean square error (RMSE) and correlation coefficient (R) of 0.0001 and 0.81, respectively. The mass balance of cadmium in the Muharram Aisha treatment plant was found to be 4832.44 g/day (37.1726%) in the treated wastewater and 8164.52 g/day (62.804%) in the sludge, which indicated that the mix liquor suspended solid (MLSS) was the most sensitive factor. The sensitivity to cadmium was analyzed via MLSS in the extended aeration system and the results o indicated that the higher the MLSS concentration (mg/L), the greater the removal of cadmium in the treated wastewater. It was found that increasing the MLSS through a biological treatment method reduced the concentration of cadmium without the need for additional of any (potentially harmful) chemical treatments. The plant was subsequently operated for a period of 5 months with the MLSS increased from 1500 to 4500 mg/L, and this reduced the concentration of cadmium in the wastewater from 0.36 to 0.01 mg/L as a consequence. This research demonstrates how the novel application of TOXCHEM can be a useful tool in the reduction of heavy metal contamination in the environment.

Biochar-based geopolymer nanocomposite for COD and phenol removal from agro-industrial biorefinery wastewater: Kinetic modelling, microbial community, and optimization by response surface methodology

Agro-industrial biorefinery effluent (AIBW) is considered a highly polluting source responsible for environmental contamination. It contains high loads of chemical oxygen demand (COD), and phenol, with several other organic and inorganic constituents. Thus, an economic treatment approach is required for the sustainable discharge of the effluent. The long-term process performance, contaminant removal and microbial response of AIBW to rice straw-based biochar (RSB) and biochar-based geopolymer nanocomposite (BGC) as biosorbents in an activated sludge process were investigated. The adsorbents operated in an extended aeration system with a varied hydraulic retention time of between 0.5 and 1.5 d and an AIBW concentration of 40–100% for COD and phenol removal under standard conditions. Response surface methodology was utilised to optimize the process variables of the bioreactor system. Process results indicated a significant reduction of COD (79.51%, 98.01%) and phenol (61.94%, 74.44%) for BEAS and GEAS bioreactors respectively, at 1 d HRT and AIBW of 70%. Kinetic model analysis indicated that the Stover-Kincannon model best describes the system functionality, while the Grau model was better in predicting substrate removal rate and both with a precision of between R2 (0.9008–0.9988). Microbial communities examined indicated the abundance of genera, following the biosorbent addition, while RSB and BGC had no negative effect on the bioreactor's performance and bacterial community structure of biomass. Proteobacteria and Bacteroidetes were abundant in BEAS. While the GEAS achieved higher COD and phenol removal due to high Nitrosomonas, Nitrospira, Comamonas, Methanomethylovorans and Acinetobacter abundance in the activated sludge. Thus, this study demonstrated that the combination of biosorption and activated sludge processes could be promising, highly efficient, and most economical for AIBW treatment, without jeopardising the elimination of pollutants or the development of microbial communities.

Removal of nutrients from pulp and paper biorefinery effluent: Operation, kinetic modelling and optimization by response surface methodology

This study investigated the effectiveness of extended aeration system (EAS) and rice straw activated carbon-extended aeration system (RAC-EAS) in the treatment of pulp and paper biorefinery effluent (PPBE). RAC-EAS focused on the efficient utilization of lignocellulosic biomass waste (rice straw) as a biosorbent in the treatment process. The experiment was designed by response surface methodology (RSM) and conducted using a bioreactor that operated at 1–3 days hydraulic retention times (HRT) with PPBE concentrations at 20, 60 and 100%. The bioreactor was fed with real PPBE having initial ammonia-N and total phosphorus (TP) concentrations that varied between 11.74 and 59.02 mg/L and 31–161 mg/L, respectively. Findings from the optimized approach by RSM indicated 84.51% and 91.71% ammonia-N and 77.62% and 84.64% total phosphorus reduction in concentration for EAS and RAC-EAS, respectively, with high nitrification rate observed in both bioreactors. Kinetic model optimization indicated that modified stover models was the best suited and were statistically significant (R2 ≥ 0.98) in the analysis of substrate removal rates for ammonia-N and total phosphorus. Maximum nutrients elimination was attained at 60% PPBE and 48 h HRT. Therefore, the model can be utilized in the design and optimization of EAS and RAC-EAS systems and consequently in the prediction of bioreactor behavior.

Evaluation of treated wastewater produced by five different Sewage Treatment Plants using three different technologies - Oman experience

ABSTRACT The quality of treated wastewater produced in five different Sewage Treatment Plants (STPs) using three different technologies, Conventional Activated Sludge (CAS), Extended Aeration System and Membrane Bioreactor (MBR) was evaluated. The CAS was the best; it had the highest general efficiency (EG) with a value of 96.6%. The STPs using EAS had maintenance problems. The MBR is relatively less efficient. In order to get treated wastewater of good quality, the standard of operation and maintenance are important; but the use of suitable technology to operate with optimum efficiency in a given environment is imperative.

The application of intermittent cycle extended aeration systems (ICEAS) in wastewater treatment

Many biological methods are currently used to treat wastewaters, such as e.g. aerobic, anaerobic, sequencing batch reactors, biofilters. However, these technologies are limited by low nutrient removal efficiency, high energy and large area requirements. Hereby, the intermittent cycle extended aeration system (ICEAS), or continuous flow sequencing batch reactor (SBR) can be an alternative solution. Therefore, understanding all aspects of this technology – such as reaction mechanisms, nitrogen conversion cycle, and operation conditions – are very necessary. This paper reviews the mechanism and key factors affecting the ICEAS operation conditions to treat many wastewaters. An ICEAS combines many biological processes as aerobic, anoxic, and anaerobic in one tank. ICEAS has some advantages compared with traditional activated sludge such as less space demand, low investment costs, low aeration to save operating costs, and automatic operation. An ICEAS shows its high efficiencies in removing organic compounds (90–97 % of COD removal) and nutrients (97–99 % of TN removal), limiting the accumulation of nitrite and nitrate. The continuous inflow feeding into ICEAS reduces organic loading shock and is beneficial to the growth of microorganisms community. Hope this paper will help to promote further application of ICEAS technology for wastewater treatment around the world.

Removal of Nutrients From Anaerobically Digested Swine Wastewater Using an Intermittent Cycle Extended Aeration System.

Swine wastewater contains high concentrations of organic compounds, nutrients (nitrogen and phosphorus), heavy metals, and residual antibiotics, amongst others, that have negative impacts on the water environment. The main aim of this work was to remove nutrients from anaerobically digested swine wastewater using an intermittent cycle extended aeration system (ICEAS). The effects of operational parameters such as cycle time, organic loading rate, C/N ratio, and aeration/mixing ratio on the pollutant removal efficiencies of ICEAS were studied and compared with the performance of a conventional sequencing batch reactor (SBR). The following optimal conditions were obtained: cycle time, 6 h; organic loading rate, 0.86 kg COD m−3 day−1; C/N ratio, 2.49–2.82; and aeration/mixing ratio, 1.57. The pH was maintained in the range of 6.0–8.0. The total organic carbon (TOC), total nitrogen (TN), ammonium (NH4+), total phosphorus (TP), and color removal efficiencies of ICEAS were higher than those of the conventional SBR, with removal efficiencies of 95.22, 88.29, 97.69, 85.81, and 97.84%, respectively, compared to 94.34, 81.16, 94.15, 77.94, and 96.95%, respectively, observed in the SBR. TOC, TN, NH4+, TP, and the color removal efficiencies of ICEAS were higher by 0.88, 7.13, 3.54, 7.87, and 0.95%, respectively, than the conventional SBR. The good results from this study show that ICEAS is a promising technology for the removal of organic contaminants and nutrients from anaerobically digested swine wastewater and that the effluent water quality meets the Vietnamese discharge standard (QCVN 62-MT:2016/BTNMT) for swine wastewater effluents.

Performance comparison of phenol removal in pharmaceutical wastewater by activated sludge and extended aeration augmented with activated carbon

This study investigated the removal of phenol, Chemical Oxygen Demand (COD), and ammonia from pharmaceutical wastewater using activated sludge (AS) and extended aeration (EA) systems. Also, the impact of adding activated carbon media on the performance of the two systems has been studied. Synthetic sewage was used with a composition of COD equaling 1500 mg/L. The experimental work was divided into five scenarios for the two reactors based on the Phenol concentration, 0.0 mg/L in the first scenario, 50.0 mg/L in the second and third scenarios, but activated carbon has been added to the third one. The concentration of Phenol was 100.0 mg/L and 150.0 mg/L for the fourth and fifth scenarios, respectively. The experimental results indicated that EA system gives higher removal efficiency than that by AS system for COD, phenol, and ammonia. In addition adding activated carbon of just 1.0 gm/L of the working reactor volume in both systems (AS, EA) has improved the removal efficiency. GPS-X simulator was employed to predict the performances of the biological systems under high effluent concentration of COD reaching up to 19000 mg/L. The simulation results indicated that EA effluent could comply with Egyptian Cod (Law no 44/2000).

Recovery of intermittent cycle extended aeration system sludge through conversion into biodiesel by in-situ transesterification

The feasibility of using intermittent cycle extended aeration system (ICEAS) sludge as a lipid feedstock for biodiesel production was investigated. The main effects of in situ transesterification parameters, reaction temperature (30–70 °C), reaction time (4–24 h), catalyst concentration (1–5% v/v), and proportion of methanol to dry sludge (5–25 ml/g) at five-levels as well as their simultaneous interactions were evaluated to develop an empirical model. Optimized conditions were obtained at 60 °C, 4.65% (v/v) H2SO4, 17.84 h reaction time, and 5:1 methanol to dry sludge proportion (ml/g), leading to a maximum of 18.58% (w/w) biodiesel yield with 94.23% fatty acid methyl ester content. This result was higher in comparison with yields derived from conventional activated sludge, membrane bioreactor and anaerobic-anoxic-oxic processes. The ICEAS technology advantages are owned to its different configurations leading to production of one blended sludge, shorter hydraulic retention time and higher chemical oxygen demand to nitrogen ratios. The predominance of fatty acid methyl esters such as palmitic, oleic, palmitoleic, stearic, linoleic and myristic acid methyl ester, in the obtained biodiesel, indicated suitability of ICEAS sludge as feedstock for biodiesel production.

Post treatment of ICEAS-biologically landfill leachate using electrochemical oxidation with Ti/BDD and Ti/RuO2 anodes

Abstract Leachate is known with high concentration of organic substances and nitrogen, which are extremely toxic to the environment. Recently, electrochemical oxidation has received much attention on account of its low cost, feasibility, environmental friendliness, and excellent in contaminants removal in wastewater. The present study reported the first time treatment of biologically leachate (after continuous flow sequencing batch reactor (CFSBR) or Intermittent Cycle Extended Aeration System (ICEAS) digestion) electrochemical oxidation using Ti/BDD and Ti/RuO2 anodes. Effects of varying operational conditions of the electrochemical oxidation process: current density, reaction time, pH, and flow rate on the pollutant removal efficiencies and energy consumptions, were studied. Final results revealed that low pH favors high organic substance removal efficiencies, but restricts low ammonium removal efficiencies, and vice versa. When using a Ti/BDD anode, COD, TOC, NH 4 + –N and total Nitrogen (TN) elimination rates achieved highest were 95.17%, 91.89%, 81.18% and 63.54%, respectively; while, with Ti/RuO2 anode, they were 92.57%, 78.76%, 97.85% and 72.12% at 83 mA cm−2 and 8 h. Ti/BDD anode showed less energy consumption and better pollutant removal efficiencies than the Ti/RuO2 anode, except for the NH 4 + –N and TN parameters. After treatment, the effluent matched with the Vietnamese discharge standards for landfill leachate effluent QCVN 25:2009/BTNMT.

Comparison of different industrial scale palm oil mill effluent anaerobic systems in degradation of organic contaminants and kinetic performance

Palm oil mill effluent has been extensively researched via three different technologies, namely chemical, physicochemical and biological treatment methods. Biological treatment by anaerobic and aerobic means is currently the most commonly used method for palm oil mill effluent. However, the greatest challenge posed by them is the inconsistent biological oxygen demand of 20 mg/L for the final treated effluent. Large amount of investment for additional polishing plant prior to the final discharge has been utilised intentionally to further reduce the biochemical oxygen demand values, but the problem remains unresolved. The performance of current palm oil mill effluent treatment system deployed by the industry was evaluated by comparing two different types of anaerobic treatments: open ponding and covered lagoon systems (with hydraulic and gas mixing). The covered lagoon with hydraulic mixing achieved the highest chemical oxygen demand, total suspended solids, total volatile solids and lignin removal efficiencies of >80% compared to other systems which showed <50% removal. Sufficient hydraulic retention time, extended aeration system coupled with presence of pure aerobic microbial cells in the stabilisation pond were able to produce effluent that abided the final discharge limit of biochemical oxygen demand 20 mg/L. Stover-Kincannon, Monod Contois and Grau second-order kinetic models were applied to the chemical oxygen demand data obtained to gauge the performance of anaerobic treatment of covered lagoon system with hydraulic mixing. The modified Stover-Kincannon model was found to define the system most appropriately with R2 of 0.9767. This work provided an up-to-date and representative palm oil mill effluent characteristics and contaminants degradation performance of the three commonly used palm oil mill effluent treatment methods in Malaysia. It helps in method selection and equipment sizing for palm oil mill effluent as well as other industrial-scale wastewater treatment and management.

Intermittent cycle extended aeration system pilot scale (ICEAS-PS) for wastewater treatment: experimental results and process simulation

Intermittent cycle extended aeration system is a modification of a conventional sequencing batch reactor system in which the system is operated under continuous feed. The objective of this research is to study the effect of sludge retention time and aeration pattern on the performance of intermittent cycle extended aeration system pilot scale for wastewater treatment. In addition, the process simulation using GPS-X software was conducted. Five different runs of sludge retention times of 10, 15, 20, 25 and 30 days were studied. The optimum sludge retention time for wastewater treatment by intermittent cycle extended aeration system pilot scale was 10 days, and under operating condition of sludge retention time of 10 days, effluent quality was 15.5 ± 3.8, 6.5 ± 1.1, 5.3 ± 1.6, 0.7 ± 0.2, 5.0 ± 1.4 mg/L and 1.4 ± 0.7 mg/L for COD, BOD5, TSS, NH4–N, TN and TP which amply met the local regulation of class A treated wastewater. GPS-X sensitivity analysis tool box was used to determine the most sensitive kinetic parameters affecting the intermittent cycle extended aeration system pilot scale performance. Out of about 50 kinetic parameters, YH, bH, μA, Ko, bA, Ka and μPAO appeared to the most sensitive kinetic parameters. The calibrated GPS-X model proved that the presence of anoxic phase in the cycle has a significant impact on nitrogen and phosphorus removal. In addition, intermittent aeration pattern achieved the highest performance compared with other patterns of aeration only, aeration/anoxic and anoxic/aeration.

Nitrogen Removal Enhancement in Extended Aeration System

Several methods of wastewater treatment systems are implemented but among these methods activated sludge process is demonstrating process in Malaysia. Fortunately, numbers of studies have been conducted to treat and remove either nitrogen or combined phosphorus and nitrogen resulted in enhancement removal of nutrients worldwide. This research aims to study the current operation in Mawar wastewater treatment plant and monitor the reduction of several parameters. The research also examines the new standard limits of effluents. From the result obtained, the monitoring of Mawar wastewater treatment plant indicates that influent concentration of majority of the parameters were in small. Despite that, the removal efficiency of several parameters was not high. That was basically because to the need of proper maintenance activities. Besides, the concentration of measured parameters in the aeration tank inlet were small. Comparison of Mawar wastewater to the typical composition of untreated domestic sewage indicated that the wastewater in Mawar wastewater treatment plant is classified as weak wastewater. The enhancement of nitrogen removal resulted in Mawar wastewater treatment plant led to decrease the removal efficiency of several parameters.

Pollutant footprint analysis for wastewater management in textile dye houses processing different fabrics

AbstractBACKGROUNDThis study investigated the water and pollution footprints of a dye house, which processed cotton knits, polyester (PES) knits and PES‐viscose woven fabrics. Experimental evaluation was carried out for each processing sequence. Variations in wastewater flow and quality were established as a function of the production program in the plant. A model evaluation of wastewater dynamics was performed and defined specifications of an appropriate treatment scheme.RESULTSThe plant was operated with a capacity of 4300 t year−1 of fabric, which generated a wastewater flow of 403 500 m3 year−1 and a COD load of 675 t year−1. The overall wastewater footprint of the plant was computed as 91 m3 t−1 and the COD footprint as 160 kg t−1 of fabric. Depending on the fabric type, results indicated expected changes in wastewater flow between 600 and 1750 m3 day−1; in COD load between 1470 and 2260 kg day−1 and in COD concentration between 1290 and 3400 mg L−1.CONCLUSIONA model simulation structured upon COD fractionation and related process kinetics revealed partial removal of slowly biodegradable COD, coupled with high residual COD, which would by‐pass treatment. Resulting biodegradation characteristics necessitated an extended aeration system, which could also enable partial breakdown of residual COD. Effluent COD could be reduced to 220–320 mg L−1 with this wastewater management strategy. © 2018 Society of Chemical Industry

Application of response surface method to compare the performance of Wetland and extended aeration system for the removal of organic matter from sanitary wastewater

Application of response surface method to compare the performance of Wetland and extended aeration system for the removal of organic matter from sanitary wastewater

Evaluación de un reactor aerobio piloto con medio de soporte de polietilentereftalato (PET) para tratamiento de efluente lechero

Se instaló un reactor piloto de flujo pistón aerobio horizontal, con medio de soporte PET (polietilentereftalato), reciclado de botellas plásticas para el tratamiento de un sustrato sintético elaborado a partir de suero lácteo, con concentraciones de demanda química de oxígeno (DQO) entre 800 y 2100 mg/L. Se utilizó un inóculo bacteriano aclimatado con el afluente a tratarse. Se determinaron eficiencias de remoción de materia orgánica del 62.2%, 85% y 94%, operando con tiempos de retención de 5.14, 6.01 y 8.01 horas y trabajando con valores de cargas orgánicas volumétricas (Lv) de 7.68, 6.19 y 4.61 kg/día.m3, respectivamente. Adicionalmente, se calculó la constante cinética de transferencia másica (k), con un valor de 0.02 m/día y por otro lado, se determinó un factor de carga (F/M) de 0.4, indicando que el proceso se asemeja a un sistema de aireación prolongada. Finalmente, se realizó un análisis de la biomasa generada en el interior del reactor, obteniendo un valor de 11560 mg/L, el cual es mayor al valor de los sistemas convencionales.

Assessing wastewater treatment in Latin America and the Caribbean: Enhancing life cycle assessment interpretation by regionalization and impact assessment sensibility

Life cycle assessment (LCA) was applied to evaluate two wastewater treatment plant (WWTP) scenarios in Latin America and the Caribbean (LAC): extended aeration (EA) and pond system (PS). The main goal was to compare the environmental performance of two WWTP technologies across all environmental impact categories in selected methods when developing new WWTP projects. As a complementary goal, we analyzed how regionalization enhances LCA interpretation through a case study illustrating the spatial variability of WWTP results for 22 Latin American and Caribbean countries.A generic LCA relying on averaged primary data from 158 WWTPs was first performed based on three LCIA methodologies: ReCiPe, IMPACT World+ (IW+) and Impact 2002+. The results were used to identify the parameters that most influence the impact scores and test the sensitivity of the choice of LCIA methodology on the conclusions. While EA is the most impactful scenario for the human health (HH) and ecosystem quality (EQ) indicators according to Impact 2002+, ReCiPe considers it to be the least impacting option. This is mainly due to the fact that ReCiPe includes the contribution of global warming impacts at the damage level whereas IMPACT 2002+ does not. For the same reason, IW+ favours EA for the HH indicator, which is dominated by global warming impacts. However, for EQ, the PS scenario scores better because of the lower relative importance of global warming impacts (GWP) as compared to eutrophication impacts (FE) at the damage level. Both the IW+ and ReCiPe methodologies point to a trade-off between the two impact categories, which dominate the impact scores for this area of protection. A sensitivity analysis was therefore carried out at the inventory level considering regional grid electricity mixes and at the impact assessment level characterizing eutrophying emissions from WWTPs with the regional CFs for the 22 LAC countries provided by the IW+ model. Results from the IW+ analysis showed that the operating conditions of WWTP in countries where 43–80% of electricity is produced from fossil fuel tend to favour PS for the EQ and HH damage categories. Operating conditions in countries with an electricity mix of over 60% hydropower favour EA due to the significant decrease in greenhouse gas emissions for the EQ and HH damage categories. The location where a WWTP operates also influences the results of the impact assessment. For example, locations with higher eutrophication characterization factors such as Brazil, where the residence time of water is higher, do not tend to favour scenarios with higher eutrophying emissions such as EA with higher EQ impact scores as compared to PS. We concluded that regionalization, both of the inventory and characterization factors, show the potential for adding relevance and discriminating power to the LCA. To address regionalization it in standard LCA practice we propose a pragmatic and stepwise iterative approach that makes it possible to regionalize the greatest contributing inventory and the most impactful assessment flow. Nevertheless, it is important to note that we only addressed the uncertainty related to known spatial variability and that it may be of major interest to apply a similar stepwise approach to any other type of uncertainty.

Upgrading secondary wastewater plant effluent by modified coagulation and flocculation, for water reuse in irrigation

In this study, the feasibility of using coagulation, flocculation, and sedimentation (CF-S) for advanced treatment of secondary effluent released from the Yazd Intermittent Cycle Extended Aeration System was investigated. Four coagulants including ferric chloride (FeCl3), polyaluminum chloride (PAC), ferrous sulfate (FeSo4), and potassium ferrate (K2FeSo4) along with Gflog C-150 as flocculant polymer were used. In this study, returned chemical sludge was considered as a modification. Preliminary CF-S processes showed that FeSO4 and K2FeO4 had low removal efficiencies. Thus, these two coagulants were abandoned and CF-S processes were continued only with PAC and FeCl3 coagulants which had higher efficiencies in the removal of biological oxygen demand (BOD5), chemical oxygen demand (COD), total suspended solids (TSS), and turbidity. Removal efficiency was higher when half of the chemical producing sludge was returned as compared with using both coagulants simultaneously along with 2 mg L−1 of C-150 as flocculant. In the optimum dosage, when half of PAC and FeCl3 sludge were returned, the volume of produced sludge was reduced by 40% and 28%, respectively, as compared without returned sludge. For the PAC coagulant in the optimum dosage with half of the sludge returned, all 2012 EPA standards of irrigation were met for both ‘processed and non-processed type’ agricultural crops.

Comparison of technical and economic efficiency of extended aeration and sequencing batch reactors processes in hospital wastewater treatment

Wastewater of hospitals can cause many risks to public health due to having a variety of pathogenic microorganisms, pharmaceutical substances, and other hazardous toxic substances. The aim of this study was to evaluate the chemical quality of effluents from wastewater treatment plant of Falsafi Hospital and Hakim Jorjani Hospital in Gorgan, Iran, and to compare them technically and economically. This descriptive-analytical study was performed on 64 samples of raw wastewater entrance and output effluent obtained from treatment plants using extended aeration process and sequencing batch reactors (SBR) in two hospitals in Gorgan. All experiments for determination of pH, free residual chlorine, biochemical oxygen demand (BOD), chemical oxygen demand (COD), and total suspended solids (TSS) were performed using standard methods. Finally, the obtained data were analyzed using t-test and Mann-Whitney test in SPSS software. Based on the results, the removal efficiency of BOD, COD, and TSS of the extended aeration system was 91, 90.8, and 95.7 percent, respectively, while these values for the SBR system were found to be 91.7, 91.9, and 95.3 Percent, respectively. Moreover, in the output of the two hospitals, pH values were recorded as 6.69 ± 0.26 and 7.33 ± 0.2 and the average amount of free residual chlorine was 0.12 and 0.13 mg/l, respectively. This study demonstrates good performances of the extended aeration activated sludge system and the SBR system in terms of reduction of pollution load to its standard limits for agriculture and irrigation purposes. However, due to slightly better efficiency, lower cost of investment, and operation compared to other methods, the SBR system is recommended.

Evaluation of the Hospital Wastewater Activated Sludge Extended Aeration System in the Removal of Estrogenic Compounds (Case Study: Khuzestan Hospitals)

Evaluation of the Hospital Wastewater Activated Sludge Extended Aeration System in the Removal of Estrogenic Compounds (Case Study: Khuzestan Hospitals)