Secondary Treatment Processes Research Articles

Analysis and Design of Sequencing Batch Reactor Basin for Sewage Treatment Plant by using Autocad

bstract: The objectives of this project are to review and evaluate sewage treatment technologies and propose a method to improve or select appropriate technology. Sequencing batch reactor (SBR) is a part of the secondary treatment process of sewage treatment. It is fill and draw-type of activated sludge system involving a single complicated mix reactor where all steps of an activated sludge process take place. The objectives of this project are to review and evaluate sewage treatment technologies and propose a method to improve or select appropriate technology. Sequencing batch reactor (SBR) is a part of the secondary treatment process of sewage treatment. It is fill and draw-type of activated sludge system involving a single complicated mix reactor where all steps of an activated sludge process take place.

Enhanced Pretreatment of Natural Rubber Industrial Wastewater Using Magnetic Seed Coagulation with Ca(OH)2

The efficiency of magnetic seed coagulation (MSC) with pH adjustment by NaOH and Ca(OH)2 as a pretreatment for high-strength natural rubber industrial wastewater (NRIWW) was compared in this study. The high content of suspended solids (SSs) and other inhibitory substances of NRIWW is a primary issue which affects its subsequent secondary and tertiary treatment processes. The MSC process with polyaluminum chloride (PAC), anionic polymer (polyacrylamide—PAM)), and magnetic seeds (MS) (ferric oxide (Fe3O4)) was proven to be a cost-effective pretreatment of NRIWW, and Ca(OH)2 showed improved pretreatment performance, with turbidity, COD, and TSS removals of 95%, 56%, and 64%, respectively. Sedimentation was enhanced from 30 min by conventional coagulation to less than 5 min by the MSC. The organic components of NRIWW reacted with MS to generate Fe–OH/Fe–OH+ linkages through processes of surface complexing and hydrogen bonding. According to fractal analysis, the MSC process optimized with Ca(OH)2 produces less complex flocs that are uniform and densely packed. Additionally, MS served as an adsorbent and promoted the development of magnetic flocs by boosting their density and size. MSC with pH adjustment by Ca(OH)2 presents a robust and cost-effective pretreatment process for NRIWW.

Combined advanced oxidation dye-wastewater treatment plant: design and development with data-driven predictive performance modeling

The recalcitrant nature of the industrial dyes poses a significant challenge to existing treatment technologies due to the stringent environmental regulations. This combined with the inefficiency of a single treatment method has led to the implementation of the combination of primary, secondary, and tertiary treatment processes, which fails during complex secondary aeration processes due to variable pH loads of industrial effluent wastewater. This article presents a modified design methodology of a pilot-scale micro-pre-treatment unit using a solar-triggered advanced oxidation process reactor that both effectively controls the influent variability at the source and mitigates textile effluents for making the discharge reusable for different industrial purposes. The proposed modified combination technique of controlled serial processes inclusive of primary, secondary, and tertiary treatment steps with ZnO/ZnO-GO NanoMat-based advanced oxidation process demonstrates complete remediation of industrial grade effluent with effective reuse of the discharge. Further, a reliable prediction model for estimating water quality parameter using machine learning models are proposed. Multi-linear regression and Artificial Neural network modeling provide simple, accurate, and robust prediction capabilities, which are evaluated for the efficiency of the processes. The generated prediction models capture the output parameters within an acceptable level of accuracy (Radj2>0.90)\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$({{\\boldsymbol{R}}}_{{adj}}^{{\\bf{2}}}\\, >\\, 0.90)$$\\end{document} and allow compliance with the discharge Inland Water Discharge Standards (IWDS).

A study of theoretical mechanism on wastewater components of paper industry with process generated radicals in gaseous and aqueous phase

The paper and pulp industries release a diverse array of hazardous chemicals into the atmosphere, water bodies, and soil. Papermaking is characterized by intricate stages including debarking, pulping, bleaching and washing. Each of these stages possesses the capacity to generate a spectrum of toxic pollutants which may be present in both gaseous and liquid phases. This includes substances such as fatty acids, aromatic compounds, polycyclic aromatic hydrocarbons, acetaldehyde, chlorinated phenols, lignin, cellulose, hemicellulose and wood extractives. Consequently, these industrial discharges contribute to the contamination of wastewater with a complex mixture of harmful compounds. Some of these compounds persist even after the secondary treatment process. The effluent from these industries contains benzaldehyde which is one of the aromatic aldehydes with the highest reported retention time. The present study focuses on the reactions between benzaldehyde and atmospheric radicals (NO, NO2, HO2, O2, and OH radical) using computational methods. The study holds prime importance in understanding reactions involving these compounds and eventually assessing their impact on the environment. Density Functional Theory (DFT) is used to calculate Gibbs’s free energy which shows the spontaneity of reactions. The results show that the production of nitrobenzaldehyde is more feasible with ∼ -53.64 kcal/mol than the other products, and these nitro derivatives are proven to have a role in the formation and growth of the secondary organic aerosols. The aqueous solution environment promotes the production of these compounds, and they have a higher reaction energy of ∼ -3.34 kcal/mol than the gas phase. The products of these reactions adversely impact health and the atmosphere, making it a necessity to decrease the reactivity of these reactions or to take necessary actions to restrict the release of these toxic contaminants before they react with atmospheric radicals.

Campus source to sink wastewater surveillance of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2)

Wastewater-based surveillance (WBS) offers an aggregate, and cost-effective approach for tracking infectious disease outbreak prevalence within communities, that provides data on community health complementary to individual clinical testing. This study reports on a 16-month WBS initiative on a university campus in England, UK, assessing the presence of SARS-CoV-2 in sewers from large buildings, downstream sewer locations, raw wastewater, partially treated and treated effluents. Key findings include the detection of the Alpha (B.1.1.7) variant in wastewater, with 70 % of confirmed campus cases correlating with positive wastewater samples. Notably, ammonium nitrogen (NH4-N) levels showed a positive correlation (ρ = 0.543, p < 0.01) with virus levels at the large building scale, a relationship not observed at the sewer or wastewater treatment works (WWTW) levels due to dilution. The WWTW was compliant to wastewater standards, but the secondary treatment processes were not efficient for virus removal as SARS-CoV-2 was consistently detected in treated discharges. Tools developed through WBS can also be used to enhance traditional environmental monitoring of aquatic systems. This study provides a detailed source-to-sink evaluation, emphasizing the critical need for the widespread application and improvement of WBS. It showcases WBS utility and reinforces the ongoing challenges posed by viruses to receiving water quality.

Treated domestic effluents for non-potable reuse: microbial risk assessment and economic viability

ABSTRACT In this study, we applied quantitative microbial risk assessment and net present value methodologies to evaluate the economic viability and safety of wastewater treatment to produce water for reuse. We found payback periods of three to over 15 years for investment in the universalisation of sanitation services in the selected municipalities, wherein the most feasible scenarios were those in which water reuse was carried out at its maximum potential. Microbial risk was assessed in terms of reduced concentrations of Escherichia coli. Results show that reuse of wastewater treated by different plant configurations for crop irrigation, involving only secondary treatment processes, presented high risk of infection for both farmers and consumers (3.50E–02 ± 3.10E–03 and 5.80E 02 ± 3.30E–03, respectively). In the urban and industrial context, it did not pose any risk beyond the tolerable risk recommended by WHO, except for the worker’s droplet ingestion route of exposure (2.40E–03 ± 3.80E–03).

Pollution control by waste: Dual metal sludges derived Ni-Al LDOs for efficient fluoride removal

Effective treatment of toxic sludge such as nickel-containing sludge (NS) and aluminum-containing sludge (AS) and fluorine pollution is of significance but challenging due to secondary pollution and complex treatment processes. Herein, a facile waste-to-waste strategy was proposed to prepare Ni-Al layered double oxides/sludge (Ni-Al LDOs/sludge) adsorbent using NS as nickel source and AS as aluminum source via hydrothermal treatment and calcination without adding any metal salts. The Ni-Al LDOs/sludge with a large specific surface area and mesoporous structure showed high F- adsorption performance. The F- adsorption mechanism exhibited monolayer adsorption which was consistent with the Langmuir isotherm model. The kinetic results showed that fluoride adsorption onto Ni-Al LDOs/sludge follows the pseudo-second order kinetic model. Significantly, the as-prepared adsorbent possessed desirable reusability and durability. Furthermore, a possible adsorption mechanism involving electrostatic attraction and ion exchange on the surface of the Ni-Al LDHs/sludge was discussed. Therefore, this work developed a method for converting toxic sludges into functional adsorbent, which provided a new strategy for comprehensive treatment of sludge and fluorine wastewater.

AN OVERVIEW OF ELECTRO-FENTON TECHNOLOGY FOR ORGANIC WASTEWATER TREATMENT: OPTIMAL CONDITIONS AND ELECTRODES SELECTION

Several conventional methods have been employed to eliminate numerous types of pollutants from domestic and industrial wastewater. Electrochemical techniques are one of these treatment methods used in wastewater treatment. Electro-Fenton technology (EFT) is one type of electrochemical technique. The present review paper aims to provide readers with extensive information about the EFT general definitions, terminologies, mechanisms, fundamental conditions, and statistical analysis based on the published articles for the recent years. The core findings of this work proved that the EFT is more applicable for removing organic contaminants than inorganic ones because of the affinity degree between the adsorbents formed in the reactor and the pollutants. The most important conditions of this technology are the type of anode, the applied current, and the period of the treatment process. The development of the conventional cathode electrode was the most interested field in the literature. The advantages of EFT provide the ability to perform it as a primary or secondary treatment process with other conventional treatment processes. The statistical analysis shows that 68% of the selected cited articles achieved a high performance of EFT when it has performed alone while 32% of these cited articles attained the best performance of EFT in the integrated system with other technologies. The electro-Fenton method is a promising technology to treat wastewater, especially that involving organic pollutants

Unraveling Electrochemical Lignin Degradation in Organic Solvent for Production of Valuable Fuels and Chemicals

Lignin is the second most abundant biopolymer in nature after cellulose. Due to its distinctive aromatic backbone, it is also one of the most unique biopolymers. The aromatic components in lignin provide structural support to plants and comprises about 30% of the plant material. These aromatic groups can be used to produce renewable aromatic compounds. Also, these aromatic compounds can be used to produce biofuels which can be promising alternative to fossil-based fuels and chemicals. Besides, from previous studies it is found that about 40 to 60 million tons of lignin are generated from pulp and paper industry, mostly as wastes. So, developing novel and attractive strategies for fragmentation of lignin is gaining increased interest among scientific community for valorizing this underexploited material. Also, by valorizing lignin the sustainability of biorefinery and paper industry can be enhanced. However, the present technologies used for degradation of lignin generally requires the use of metallic catalysts at high temperatures and harsh reaction conditions. As a result, catalyst recovery and decomposition often become difficult under such harsh conditions and the process becomes impractical. Also, these technologies suffer from poor selectivity and usually produce the desired fragmentation products in low yields. Compared to the thermocatalytic transformation of lignin, electrocatalytic approaches have several advantages like it is environmentally friendly, have mild reaction conditions and the cost is low. Besides, there is a lack of studies incorporating electrocatalytic oxidation and reduction of lignin in organic solvent. In this project, the main goal was to overcome the challenge of using isolated lignin from various industrial processes by electrochemical depolymerization of lignin in organic solvent like tetrahydrofuran. Tetrahydrofuran is mainly used in Co-solvent Enhanced Lignocellulosic Fractionation (CELF) process. So, electrocatalytic degradation of lignin in this solvent is beneficial because the product from CELF process can be directly used here and thus it can work as a secondary treatment process for CELF process. Cyclic voltammetry (CV) and Chronoamperometry (CA) which are important tools for identifying redox reactions happening in the system is used here. In this presentation, for varying concentrations of Lignin, Tetrahydrofuran and sulfuric acid the results found from CV and CA will be discussed with practical significance.Keywords: Recalcitrant biopolymer, Lignin in organic solvent, controlled electrocatalysis, secondary treatment for CELF process, Cyclic Voltammetry

Occurrence and Fate of Steroid Hormones in Sewage Treatment Plants

Sewage treatment plants (STPs) are one of the crucial barriers for the environmental emission of steroid hormones. Insights into the occurrence and fate of different categories of steroid hormones in STPs could provide theoretical support for improving steroid removal by STPs. The present study investigated 22 steroid hormones in each treatment process of two STPs located in Wuxi via eight monthly sampling campaigns and compared the efficacy of Anaerobic-Anoxic-Aerobic (A2/O) and reversed A2/O treatments. The results showed that the total steroid concentrations in the influent and effluent were 27.7-256.8 ng·L-1 and 5.7-211.0 ng·L-1, respectively, and 36.3-123.6 ng·g-1 in the excess sludge. Androsterone, androstenedione, estrone, estriol, and progesterone were the main species detected in the STPs. The concentrations of most steroids increased with the rise of rainfall and temperature, whereas the removal rates were not significantly different between winter and summer. Secondary and tertiary treatment processes showed better performance in steroid removal compared with that in the primary treatment; however, reversed A2/O did not show advantages over traditional A2/O. The organic-normalized partition coefficients (lg Koc) of steroids ranged between 2 and 4.5. The values of lg Koc in STP A were slightly greater than those in STP B, indicating that the partition behavior of steroids may influence their treatment efficacies.

Mechanical crystallization induced Sm3+-doped CsPbBr3 quantum dots glass for high-sensitivity temperature sensing

The traditional preparation methods of quantum dots (QDs) for temperature sensing are limited to self-crystallization and secondary heat treatment processes, which requires precise control of the experimental equipment and conditions. In this paper, CsPbBr3 QDs are successfully obtained by friction crystallization in the prepared precursor glass. The results show that when the glass network structure is subjected to continuous mechanical impact, the thermal kinetic energy of the fracture surface increases. Therefore, the combination of relatively loose structure and local thermal energy supply more excellent space for the nucleation and growth of CsPbBr3 QDs. Furthermore, the PL enhancement is confirmed to be occur in Sm3+ ions doped CsPbBr3 QDs, which is due to the increase of density of exciton states near the edge of the band, thus facilitating radiative recombination. Significantly, this material has a favorable performance of temperature sensing and thermal stability, with the maximum relative sensitivity of 3.09 % K−1. This work provides an energy-saving and green way for the preparation of Sm3+ ions doped QDs, and the materials provide potential applications in the field of temperature sensing.

Imperative assessment on the current status of rubber wastewater treatment: Research development and future perspectives

The environment has been significantly impacted by the rubber industry through the release of large quantities of wastewater during various industrial processes. Therefore, it is crucial to treat the wastewater from the rubber industry before discharging it into natural water bodies. With the understanding that alarmingly depleting freshwater sources need to be preserved for future generations, this paper reviews the status of the rubber industry and the pollution caused by them, focusing mainly on water pollution. The review pays special attention to the recent advancements in wastewater treatment techniques for rubber industry wastewater categorizing them into pre-treatment, secondary, and tertiary treatment processes while discussing the advantages and disadvantages. Through a comprehensive analysis of existing literature, it was determined that organic content and NH4+ are the most frequently focused water quality parameters, and despite some treatment methods demonstrating superior performance, many of the methods still face limitations and require further research to improve systems to handle high organic loading on the treatment systems and to implement them in industrial scale. The paper also explores the potential of utilizing untreated or treated wastewater and byproducts of wastewater treatment in contributing towards achieving several United Nations sustainable development goals (UN-SDGs); SDG 6, SDG 7, SDG 9, and SDG 12.

Removal of microplastics in wastewater by ceramic microfiltration

Microplastic (MP) pollution is a growing global concern affecting environmental water quality. Although primary and secondary treatment processes in conventional wastewater treatment plants (WWTPs) efficiently remove MPs, MPs <20 μm across are not removed effectively. The quality of final effluent should be enhanced by applying a tertiary treatment for reducing MP discharge from WWTPs. This study evaluated the effectiveness of ceramic membranes for this. Removal of MPs was assessed at laboratory scale by cross-flow filtration of a secondary wastewater effluent. The activated sludge process at a wastewater treatment plant removed MPs at moderate to high rates (45 %–98 %), and the ceramic membranes further removed >72 % of MPs. Although the activated sludge process removed variable rates of MPs, the total rates of removal by both processes was >96 %. This result suggests that the ceramic MF membrane treatment will contribute to stable MP removal.

Developments and expansions of a suite of trickling filters models

AbstractIn the United Kingdom, trickling filters remain the most widespread secondary biological treatment process for municipal sewage treatment in terms of number of installations. Ongoing improvement in environmental quality of surface waters requires many of these sites to meet stringent effluent standards. Since publication of the original model for nitrification on mineral media trickling filters by Pearce and Williams in 1999 and the model for nitrification on plastic media filters by Pearce and Edwards in 2010, they have attracted widespread use. Since publication, the models have undergone some refinement and benefitted from an increased application range. Furthermore, recent publications by Pearce and Yang have delivered widely based models for predicting average and seasonal humus tank effluent suspended solids and variability at a resolution of daily 95th percentile performance. This paper presents recent developments of the nitrification models and consolidates the suite of models now available for trickling filter design, evaluation and operation.

Effects of Wastewater Treatment Processes on the Removal Efficiency of Microplastics Based on Meta-analysis

Microplastics (MPs) are ubiquitous emerging pollutants that have been found in the marine, freshwater, air, and soil environments. Wastewater treatment plants (WWTPs) play an important role in releasing MPs to the environment. Therefore, understanding the occurrence, fate, and removal mechanism of MPs in WWTPs is of great importance towards microplastic control. In this review, the occurrence characteristics and removal rates of MPs in 78 WWTPs from 57 studies were discussed based on Meta-analysis. Specifically, the key aspects regarding MPs removal in WWTPs, such as wastewater treatment processes and MPs shapes, sizes, and polymer compositions were analyzed and compared. The results showed that:① the abundances of MPs in the influent and effluent were 1.56×10-2-3.14×104 n·L-1 and 1.70×10-3-3.09×102 n·L-1, respectively. The abundance of MPs in the sludge ranged from 1.80×10-1 to 9.38×103 n·g-1. ② The total removal rate (>90%) of MPs by WWTPs using oxidation ditch, biofilm, and conventional activated sludge treatment processes was higher than that using sequencing batch activated sludge, anaerobic-anoxic-aerobic, and anoxic-aerobic processes. ③ The removal rate of MPs in primary, secondary, and tertiary treatment process were 62.87%, 55.78%, and 58.45%, respectively. The combination process of "grid+ sedimentation tank+primary sedimentation tank" had the highest removal rate towards MPs in primary treatment processes, and the membrane bioreactor had the highest one beyond other secondary treatment processes. Filtration was the best process in tertiary treatment. ④ The film, foam, and fragment MPs were easier to remove (>90%) than fiber and spherical (<90%) MPs by WWTPs. The MPs with particle size larger than 0.5 mm were easier to remove than those with particle size smaller than 0.5 mm. The removal efficiencies of polyethylene (PE), polyethylene terephthalate (PET), and polypropylene (PP) MPs were higher than 80%.

Occupational Health Risk Assessment for Wastewater Treatment and Reuse in Kanpur, India.

The treatment and reuse of wastewater for irrigation can lead to occupational health risks for sewage treatment plant (STP) workers and farmers. Sanitation Safety Planning (SSP) is an approach which can be used to measure and mitigate these risks. This paper explores what impact a novel secondary treatment process, consisting of an integrated permeate channel (IPC) membrane combined with a constructed wetland plus, has on the occupational health risks compared with the existing activated sludge wastewater treatment process and reuse system in Kanpur, Uttar Pradesh. A mixed methodology was used, which included key informant interviews, structured observations, and E. coli analysis. This data was used to undertake semi-quantitative risk assessments following the SSP approach. The novel secondary treatment increased the number of health risks which the STP workers were exposed to, but the severity of the risks was lower. This was due to the differences in treatment processes and infrastructures. The number of health risks for the farmers decreased both in number and severity. For their children, the severity of the health impacts decreased. These changes were due to the increase in the microbiological quality of the irrigation water. This study highlights the potential of using a semi-quantitative risk assessment to assess the occupational health impacts of using novel treatment technologies.

Removal of Toluidine blue in water using green synthesized nanomaterials

Green synthesis is a simple, eco-friendly, and emerging approach to synthesizing nanoparticles and is currently attracting the scientific community worldwide. The objective of the present study was to synthesize green titanium dioxide NPs and evaluate their performance for the photocatalytic treatment of textile wastewater after the secondary treatment process. TiO2 NPs were synthesized using leaf extracts of asausage tree (Kigelia Africana) in asingle step. The green synthesized TiO2 NPs were characterized by Scanning Electron Microscopy (SEM), Energy Dispersive X-ray spectroscopy (EDX), X-Ray Diffraction (XRD), Fourier-Transform Infrared spectroscopy (FT-IR), Diffuse Light Scattering spectroscopy (DLS), Transmission Electron Microscopy (TEM). The findings validated the synthesis of the spherical-shaped TiO2 NPs and their anatase phase. The green-produced TiO2 NPs were used for the treatment of textile effluent. During the photocatalytic treatment of aself-designed dye solution, 99.59% removal of Toluidine blue(TB) dye was achieved within 60 minupon the treatment of green synthesized TiO2 NPs studied by a UV–Visible spectrophotometer. Therefore, the green TiO2NPs that were developed have been examined for the treatment of wastewater, and the catalyst has reusability make it more efficient and affordable, and it might be used to remove organic dyes from textile industries

An assessment of the impact of structure and type of microplastics on ultrafiltration technology for microplastic remediation.

Microplastic, which is of size less than 5 mm, is gaining a lot of attention as it has become a new arising contaminant because of its ecophysiology impact on the aquatic environment. These microplastics are found in freshwater or drinking water and are the major carriers of pollutants. Removal of this microplastic can be done through the primary treatment process, secondary treatment process, and tertiary treatment process. One approach for microplastic remediation is ultrafiltration technology, which involves passing water through a membrane with small pores to filter out the microplastics. However, the efficiency of this technology can be affected by the structure and type of microplastics present in the water. New strategies can be created to improve the technology and increase its efficacy in removing microplastics from water by knowing how various types and shapes of microplastics react during ultrafiltration. The filter-based technique, that is, ultrafiltration has achieved the best performance for the removal of microplastic. But with the ultrafiltration, too some microplastic that are of sizes less than of ultrafiltration membrane passes through the filter and enters the food chain. Accumulation of this microplastic on the membrane also leads to membrane fouling. Through this review article, we have assessed the impact of the structure, size, and type of MPs on ultrafiltration technology for microplastic remediation, with that how these factors affect the efficiency of the filtration process and challenges occur during filtration.

Ultrasonication pretreatment of real-field pulping wastewater from bagasse-based paper mill

In this study an attempt has been made to evaluate the feasibility of utilizing ultrasonication as pretreatment process to treat pulping wastewater. Bio-electrochemical treatment and microalgal treatment have been used as secondary treatment process. Ultrasonication was performed in bath type sonicator at 60 kHz for various time intervals of 15, 30, 45 and 60 min. There were no significant changes in pH, TDS and COD of pulping wastewater after ultrasonication. The bio-electrochemical treatment of pretreated wastewater did not show significant improvement in treatment efficiency and color removal. Rather the MFC operating with pretreated wastewater showed poor electrochemical performance. Microalgae consortia collected from lily pond in the institute could decolorize the ultrasonically pretreated wastewater, but color of raw wastewater could not be decolorized by micro algal consortia. Ultrasonication could have modified the compounds in pulping wastewater, making them more accessible to microalgal metabolism.

Exploration of the effect of simultaneous removal of EDCs in the treatment process of different types of wastewater.

The SPE-HPLC-MS/MS method was used to investigate the concentration distribution of nine types of estrogens in 18 locations of pollution source along the Jiuzhou River belonging to river systems in Guangdong province and Guangxi Zhuang autonomous region in China, and the estrogenic activity and potential ecological risks were evaluated by calculating the estradiol equivalency (EEQ). The results showed that the calculated estradiol equivalents (cEEQs) of wastewater treatment plants from 17 locations were all higher than 1 ng/L. To further study the removal effect of the treatment process on the estrogens, the pig breeding wastewater from P4 and the municipal wastewater from P13, as well as the black-odorous water, were sampled and surveyed during the entire process. It turned out that estrogens were effectively removed after nitrification activated sludge treatment. Meanwhile, there was a positive correlation between the removal of NH3-N, total nitrogen (TN) and total phosphorus (TP) and the removal of endocrine disrupting chemicals (EDCs). It is shown in the study the secondary treatment process has achieved a significant effect on the removal of estrogen in both the wet and dry periods and that there has been a positive correlation between the activities of total phosphorus compounds, nitrogen-based compounds and the removal of EDCs.