Municipal Sewage Treatment Plant Research Articles

Feasibility Analysis of Municipal Wastewater Reinjection Technology

To study the feasibility of using municipal sewage as a reserve water source for oilfield reinjection, the water sample treated by the municipal sewage treatment plant and the produced water of the Chang 2 reservoir were taken as the research objects. Through the analysis of water quality and compatibility, the optimal ratio of reinjection water samples was determined. At the same time, the clay swelling experiment and reservoir damage experiment were carried out. The experimental results show that the salinity of municipal sewage is low, and the content of scale ions is low. When the ratio of produced water to municipal sewage is 7:3, the scale formation amount can reach 42.5 mg.L-1, and when the scale inhibitor is added, the scale formation amount can be reduced to 10.4 mg.L-1. The mixed water sample will not cause clay expansion. Meanwhile, Chang 2 reservoir is moderately weak water sensitive and weak acid sensitive. The oil content, suspended solids content, and median particle size of the mixed water sample during reinjection should be controlled at 5 mg.L-1, 5 mg.L-1, and 5 μm to ensure that the reinjected water sample does not cause damage to the reservoir.

Parachitinimonas caeni gen. nov., sp. nov., a novel member of family Burkholderiaceae isolated from activated sludge collected in Shenzhen, PR China.

A Gram-stain-negative, strictly aerobic and filamentous bacterial strain, designated as DQS-5T, was isolated from the activated sludge of a municipal sewage treatment plant in Shenzhen, PR China. Optimal growth was observed at 28 °C and pH 7.5. Catalase and oxidase activities were detected. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain DQS-5T was most closely related to the genera Chitinimonas and Chitinivorax (91.0-93.4 % and 92.5 % 16S rRNA gene sequence similarity, respectively) and was close to the member of the family Burkholderiaceae. The complete genome sequence of strain DQS-5T contains 5 653 844 bp and 57.3 mol% G+C. The average nucleotide identity, digital DNA-DNA hybridization and average amino acid identity values between the genome of strain DQS-5T and those of its close relatives were 75.9-77.2, 19.0-20.3 and 57.2-61.8 %, respectively. Chemotaxonomic analysis of strain DQS-5T indicated that the sole respiratory quinone was ubiquinone-8, the predominant cellular fatty acids were C16 : 0 and summed feature 3 (C16 : 1 ω7c and/or C16 : 1 ω6c), and the major polar lipids consisted of phosphatidylethanolamine, phosphatidylglycerol, aminophospholipid and aminolipid. The phylogenetic, genotypic, phenotypic and chemotaxonomic data demonstrate that strain DQS-5T represents a novel species in a novel genus within the family Burkholderiaceae, for which the name Parachitinimonas caeni gen. nov., sp. nov., is proposed. Strain DQS-5T (=KCTC 92788T=CCTCC AB 2022320T) is the type and only strain of P. caeni.

Comparison on removal performance of virus, antibiotic-resistant bacteria, cell-associated and cell-free antibiotic resistance genes, and indicator chemicals by ozone in the filtrated secondary effluent of a sewage treatment plant

Due to the widespread appearance of viruses, antibiotic-resistant bacteria (ARBs), and antibiotic resistance genes (ARGs) in the aquatic environment, more powerful oxidation processes such as ozonation are needed to enhance the efficiency of their inactivation and removal during wastewater treatment. However, information is lacking on the elimination rates of viruses, ARBs, cell-associated ARGs (ca-ARGs), and cell-free ARGs (cf-ARGs) during ozonation. This study examined the kinetics and dose-dependent inactivation of a virus (MS2 coliphage) and an ARB (Ampicillin-resistant [AmpR] E. coli) and the removal of ca- and cf-ARGs (plasmid-encoded blaTEM) by ozonation in a filtered secondary effluent (SE) of a municipal sewage treatment plant (STP). In addition, the ozonation kinetics of carbamazepine (CBZ) and metoprolol (MTP)—ubiquitous organic micropollutants with different removal rate constants—were also investigated in order to monitor their effectiveness as indicators for the abovementioned biological risk factors. Our results showed that ozonation was an efficient way to remove MS2, AmpRE. coli, ARGs, CBZ, and MTP. We investigated the kinetics of their inactivation/removal with respect to exposure in terms of CT (dissolved ozone concentration C and contact time T) value, and found their inactivation/removal constants were in the following order: MS2 (8.66 ×103 M−1s−1) ≈ AmpRE. coli (8.19 ×103 M−1s−1) > cf-ARG (3.95 ×103 M−1s−1) > CBZ (3.21 ×103 M−1s−1) > ca-ARG (2.48×103 M−1s−1) > MTP (8.35 ×102 M−1s−1). In terms of specific ozone dose, > 5-log inactivation of MS2 was observed at > 0.30 mg O3/mg DOC, while > 5-log inactivation of AmpRE. coli was confirmed at 1.61–2.35 mg O3/mg DOC. Moreover, there was almost no removal of ca-ARG when the specific ozone dose was < 0.68 mg O3/mg DOC. However, 2.86–3.42-log removal of ca-ARG was observed at 1.27–1.31 mg O3/mg DOC, while 1.14–1.36-log removal of cf-ARG was confirmed at 3.60–4.30 mg O3/mg DOC. As alternative indicators, > 4-log removal of CBZ was observed at > 1.00 mg O3/mg DOC, while > 2-log removal of MTP was confirmed at > 2.00 mg O3/mg DOC. Thus, it was observed that inactivation of E. coli needs a greater ozone dose to achieve the same level of inactivation of AmpRE. coli; for ARGs, cf-ARG can persist longer than ca-ARG if low dosages of ozone are applied in the filtrated SE, CBZ might act as an indicator with which to monitor the inactivation of viruses and ARBs, while MTP might act as an indicator with which to monitor removal of ARGs. Moreover, cf-ARG cannot be neglected even after ozonation due to the possibility that ca-ARGs can become cf-ARGs during ozonation and be discharged with the final effluent, posing a potential risk to the receiving environment.

A small step to discover candidate biological control agents from preexisting bioresources by using novel nonribosomal peptide synthetases hidden in activated sludge metagenomes.

Biological control agents (BCAs), beneficial organisms that reduce the incidence or severity of plant disease, have been expected to be alternatives to replace chemical pesticides worldwide. To date, BCAs have been screened by culture-dependent methods from various environments. However, previously unknown BCA candidates may be buried and overlooked because this approach preferentially selects only easy-to-culture microbial lineages. To overcome this limitation, as a small-scale test case, we attempted to explore novel BCA candidates by employing the shotgun metagenomic information of the activated sludge (AS) microbiome, which is thought to contain unutilized biological resources. We first performed genome-resolved metagenomics for AS taken from a municipal sewage treatment plant and obtained 97 nonribosomal peptide synthetase (NRPS)/polyketide synthase (PKS)-related gene sequences from 43 metagenomic assembled bins, most of which were assigned to the phyla Proteobacteria and Myxococcota. Furthermore, these NRPS/PKS-related genes are predicted to be novel because they were genetically dissimilar to known NRPS/PKS gene clusters. Of these, the condensation domain of the syringomycin-related NRPS gene cluster was detected in Rhodoferax- and Rhodocyclaceae-related bins, and its homolog was found in previously reported AS metagenomes as well as the genomes of three strains available from the microbial culture collections, implying their potential BCA ability. Then, we tested the antimicrobial activity of these strains against phytopathogenic fungi to investigate the potential ability of BCA by in vitro cultivation and successfully confirmed the actual antifungal activity of three strains harboring a possibly novel NRPS gene cluster. Our findings provide a possible strategy for discovering novel BCAs buried in the environment using genome-resolved metagenomics.

Assessment of the Wanyu River (China) based on a water, sediment and hydrobiont framework.

Due to the striving for the development of economy and agriculture, anthropogenic activities in many countries dramatically alter natural hydrology. These activities are primarily responsible for river deterioration. Thus, we need to assess the river environment and take measures for remediation. According to the survey data, the study identified the critical factors causing water quality deterioration and evaluated the aquatic biodiversity in the Wanyu River. First, based on the monitoring data of water (dissolved oxygen (DO), chemical oxygen demand (COD), total phosphorus (TP), and ammonia nitrogen (NH3-N)), sediment (copper (Cu), zinc (Zn), lead (Pb), arsenic (As), nickel (Ni), mercury (Hg), cadmium (Cd), and chromium (Cr)), and aquatic biodiversity (fish and hydrophyte), the study identified the critical factors causing river quality deterioration. Second, the study provided some recommendations that would consolidate the restoration efforts. Consequently, because of the government's efforts in building the municipal sewage treatment plant, dredging, and other measures, the river environment improved during the 2020-2021 period. The maximum concentrations of COD, NH3-N, and TP in water were reduced by 17.76%, 26.17%, and 20.93%, respectively. The sediment had no risk of heavy metal pollution in the past 2years. And we could utilize sludge as garden soil or compost resource. However, reducing agricultural pollution, internal nutrient loading, and cost-effective restoration and evaluation represent significant challenges in the efforts to recover the river ecosystem.

Water quality for agricultural irrigation produced by two municipal sewage treatment plants in Santiago Island-Cape Verde: Assessment of chemical parameters and pharmaceutical residues

Abstract Cape Verde, a West Africa Island country, is exposed to climate change effect. An effective way of reducing its poverty and achieving food security is to provide its agricultural sector with water. The purpose of this study is to monitor treated water quality to ensure that any pollutants are below the limits set to ensure the safety and sustainability of reuse because only 10% of its treated wastewater is reused. For the first time on Cape Verde islands, besides chemical quality, the occurrence of 11 pharmaceutical compounds (PhC) in the influent and effluent of two natural wastewater treatment plants (WWTPs) was monitored to assess the effectiveness of the treatment technologies and removal efficiencies of these pollutants. Of the 11 target PhC, nine were detected in influent samples within the ng·L−1 to μg·L−1 range. Lower concentrations were detected in one WWTP vs. the other. Nevertheless, the removal efficiencies for most compounds were similar in both WWTPs: within the ranges of 82–92% for beta-blockers, 48–99% for stimulants and 44–95% for nonsteroidal anti-inflammatories, while carbamazepine (anticonvulsant) concentrations increased in effluents. WWTPs produce water that meets water quality standards for irrigation if a properly designed and managed reusing system is adopted.

Phthalate esters in municipal sewage treatment plants: occurrence level, removal rate and optimum combination technology

The concentrations, and removal rates of five phthalate esters (PAEs) (dimethyl phthalate (DMP), diethyl phthalate (DEP), dibutyl phthalate (DBP), diisobutyl phthalate (DiBP) and di (2-ethylhexyl) phthalate (DEHP)) in the five representative sewage treatment plants of Chaohu catchment were investigated by season in this study. Our results showed that five PAEs were ubiquitous contaminants in the five sewage treatment plants. Thereinto, the contents of DiBP were significantly higher than that of the other four kinds of PAEs, and the total concentrations of PAEs in the influents in summer (17.51–33.93 μg L−1) were significantly higher than those in winter (10.14–24.08 μg L−1). Different PAEs showed different removal efficiencies in sewage treatment plants, and the orders of individual removal rates was as follows: DMP &amp;gt; DEP &amp;gt; DBP &amp;gt; DiBP &amp;gt; DEHP. The total concentration of PAEs in the effluent was relatively low in Chaohu catchment. The biochemical treatment section of the sewage treatment plant contributed the most to the removal of total PAEs, while the pretreatment and advanced treatment sections contributed less. In addition, environmental temperature had an obvious effect on the biochemical treatment process. Appropriate combined treatment processes could efficiently improve the removal effect of PAEs in sewage treatment plants.

Trimethoprim resistance in surface and wastewater is mediated by contrasting variants of the dfrB gene.

Trimethoprim (TMP) is a low-cost, widely prescribed antibiotic. Its effectiveness is increasingly challenged by the spread of genes coding for TMP-resistant dihydrofolate reductases: dfrA, and the lesser-known, evolutionarily unrelated dfrB. Despite recent reports of novel variants conferring high level TMP resistance (dfrB10 to dfrB21), the prevalence of dfrB is still unknown due to underreporting, heterogeneity of the analyzed genetic material in terms of isolation sources, and limited bioinformatic processing. In this study, we explored a coherent set of shotgun metagenomic sequences to quantitatively estimate the abundance of dfrB gene variants in aquatic environments. Specifically, we scanned sequences originating from influents and effluents of municipal sewage treatment plants as well as river-borne microbiomes. Our analyses reveal an increased prevalence of dfrB1, dfrB2, dfrB3, dfrB4, dfrB5, and dfrB7 in wastewater microbiomes as compared to freshwater. These gene variants were frequently found in genomic neighborship with other resistance genes, transposable elements, and integrons, indicating their mobility. By contrast, the relative abundances of the more recently discovered variants dfrB9, dfrB10, and dfrB13 were significantly higher in freshwater than in wastewater microbiomes. Moreover, their direct neighborship with other resistance genes or markers of mobile genetic elements was significantly less likely. Our findings suggest that natural freshwater communities form a major reservoir of the recently discovered dfrB gene variants. Their proliferation and mobilization in response to the exposure of freshwater communities to selective TMP concentrations may promote the prevalence of high-level TMP resistance and thus limit the future effectiveness of antimicrobial therapies.

Removal Efficiency and Fate of Chlorinated Paraffins (CPs) in a Municipal Sewage Treatment Plant near a Typical Petrochemical Park

Water resources play an important role in industrial, agricultural, and public activities. Chlorinated paraffins (CPs) in wastewater generated by these activities provide an important source of CP contamination. In this study, the occurrences of short-chain chlorinated paraffins (SCCPs) and medium-chain chlorinated paraffins (MCCPs) were simultaneously studied in a typical sewage treatment plant (STP) near China’s second-largest oil production base over a 1-year period. High levels of SCCPs and MCCPs (3809 ± 670 and 4803 ± 478 ng/L) were found in the influent due to receiving 75% of industrial wastewater. C14-CPs was the predominant congener group, accounting for 37% of the total CP concentrations. The dissolved removal efficiency of CPs was 83.5%. Mass balance results demonstrated that 3.2% of the initial CPs was found in the final effluent, and 66.3% of the initial CPs was found in the dehydrated sludge, while 30.4% of the initial CPs was lost due to the biodegradation and volatilization. This indicated that sorption onto sludge was the main fate of CPs in wastewater treatment. High mass fractions of CPs were found in the final effluent and dewatered sludge in the winter season due to the low biodegradation, biotransformation, and volatilization.

Basic micro-pollutants in sludge from municipal wastewater treatment plants in the Northwest Spain: Occurrence and risk assessment of sludge disposal

Sludge is one of the most problematic residues generated during wastewater treatment. Herein, we validate a single-step, sensitive procedure for the determination of a selection of 46 basic micro-pollutants, either used as pharmaceuticals or pesticides, in sludge from municipal sewage treatment plants (STPs), using liquid chromatography tandem mass spectrometry as determination technique. The proposed method permitted to achieve accurate recoveries (values from 70% to 120%, for samples spiked at different concentration levels) using solvent-based calibration standards. This feature, combined with limits of quantification lower than 5 ng g−1 (dry weight), allowed the rapid and sensitive quantification of target compounds in freeze-dried sludge samples. Out of 46 investigated pollutants, 33 species showed detection frequencies above 85% in a group of 48 sludge samples, obtained from 45 STPs located in the Northwest of Spain. The assessment of eco-toxicological risks associated to sludge disposal as fertilizer in agriculture and/or forestry, considering average concentrations found in sludge samples, highlighted eight pollutants (sertraline, venlafaxine, N-desethyl amiodarone, amiodarone, norsertraline, trazodone, amitriptyline and ketoconazole) representing an environmental hazard based on ratios between predicted soil levels and non-effect concentrations estimated using the equilibrium partition method.

Research on Safety Evaluation of Municipal Sewage Treatment Plant Based on Improved Best-Worst Method and Fuzzy Comprehensive Method

With the rapid development of urbanization and industrialization, water resources are in increasingly short supply, and the construction of sewage treatment plants can ensure the sustainable development of water resources. To eliminate the potential safety hazards of municipal sewage treatment plants and prevent safety accidents from the source, this paper takes a municipal sewage treatment plant in Changchun as the research object, puts forward the evaluation method of the “improved Best-Worst Method (BWM)—fuzzy comprehensive evaluation method”, and carries out safety evaluation research on the research object. Firstly, combined with the technological process of sewage treatment plants, the evaluation index system is constructed from four factors: human factors, material factors, environmental factors, and management factors. Secondly, the improved BWM is used to calculate the weights. Finally, the fuzzy comprehensive evaluation method is used for safety evaluation, and the evaluation of safety status is obtained: the safety level.

The activation of peroxymonosulfate by biochar derived from anaerobic and aerobic iron-containing excess sludge.

The excess sludge from municipal sewage treatment plants is rich in Fe (III) due to chemical dephosphorization. The activation of peroxymonosulfate (PMS) by biochar derived from anaerobic and aerobic iron-containing excess sludge was studied systematically in this research. Fe (III)-containing excess sludge was cultured in an anaerobic environment for conversion of partial Fe (III) to Fe (II), which was further carbonized to prepare biochar labeled AnSx@Fe. Meanwhile, aerobic sludge with different Fe (III) content was directly carbonized to produce biochar labeled AeS@Fe. For biochar (AnS20@Fe-15%) prepared from 15% Fe(III)-containing anaerobic cultured 20days sludge, the relative contents of Fe (III) and Fe (II) were 21.26% and 78.74%, which were 31.03% and 68.97% for biochar (AeS@Fe-10%) prepared from 10% Fe (III)-containing aerobic sludge. Fe (III) can be reduced to Fe (II) by both anaerobic culture and carbonization.Their removal rates of tetracycline (TC) through 60min PMS activation were 97% and 98%, with TOC (Total organic carbon) removal of 61.8% and 53.4% respectively. The reactive species including sulfate radical [Formula: see text], hydroxyl radical (·OH) and singlet oxygen (1O2) were produced during PMS activation. After O2-aeration treatment of both AeS@Fe and AnSx@Fe, the relative content of Fe (II) was decreased and group C = O was disappeared, which resulted in reduction of [Formula: see text], ·OH and 1O2. The generation of [Formula: see text] and ·OH was dominated by the Fe (II) activation and the 1O2 generation was originated from graphite type N and C = O. Direct carbonization of aerobic and anaerobic sludge is a feasible method to produce biochar for PMS activation.

Sources and spatiotemporal distribution characteristics of nitrogen and phosphorus loads in the Haihe River Basin, China

Water quality monitoring stations are crucial for detecting excess pollutants in river sections, but identifying the causes of these exceedances can be challenging, especially in heavily polluted rivers with multiple contamination sources. To address this issue, we used the SWAT model to simulate pollution loads from various sources in the Haihe River Basin, analyzing the spatiotemporal distribution of pollutants from seven nitrogen/phosphorus sources in sub-basins. Our results show that crop production is the primary contributor to nitrogen and phosphorus loads in the Haihe River Basin, with the highest loads occurring in summer, followed by fall, spring, and winter. However, industries, atmospheric deposition, and municipal sewage treatment plants have a greater downstream impact on nitrogen/phosphorus contributions due to land use changes. The study highlights the need for targeted prevention and control policies based on the primary sources of pollution loads in different regions.

Co-Combustion Characteristics of Municipal Sewage Sludge and Coal in a Lab-Scale Fluidized Bed Furnace

The co-combustion of dry coal and sludge was carried out in a self-built laboratory scale fluidized bed furnace. We used FTIR spectroscopy, high-resolution gas chromatography, high-resolution mass spectrometry, and XRF to capture and dynamically observe the flue gas fly ash and bottom ash. The sludge sample was taken from a municipal sewage treatment plant and its mixing ratio was below 20%. The temperature distribution of the furnace was observed and the emissions of the main gaseous pollutants such as SO2, NOx, and dioxins were measured in the combustion process. The heavy metal contents of fly ash and bottom ash were later detected to analyze the migration characteristics. The results showed that all of the gaseous pollutants measured increased linearly with the sludge mixing ratio. However, it could also meet the 1 metal content of bottom ash and fly ash did not change much. Through the elaboration of the above points, this study can provide guidance for future research on the co-combustion of coal boiler sludge and suggest favorable conditions for the co-combustion of coal boiler sludge.

Correlations among Antibiotic Resistance Genes, Mobile Genetic Elements and Microbial Communities in Municipal Sewage Treatment Plants Revealed by High-Throughput Sequencing.

Municipal sewage treatment plants (MSTPs) are environmental pools for antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs), which is cause for growing environmental-health concerns. In this study, the effects of different wastewater treatment processes on microbial antibiotic resistance in four MSTPs were investigated. PCR, q-PCR, and molecular cloning integrally indicated that the tetracycline resistance (tet) genes significantly reduced after activated-sludge treatment. Illumina high-throughput sequencing revealed that the broad-spectrum profile of ARGs and mobile element genes (MGEs) were also greatly decreased by one order of magnitude via activated sludge treatment and were closely associated with each other. Correlations between ARGs and bacterial communities showed that potential ARB, such as Acinetobacter, Bacteroides, and Cloaibacterium, were removed by the activated-sludge process. Sedimentation processes cannot significantly affect the bacterial structure, resulting in the relative abundance of ARGs, MGEs, and ARB in second-clarifier effluent water being similar to activated sludge. A comprehensive study of ARGs associated with MGEs and bacterial structure might be technologically guided for activated sludge design and operation in the MSTPs, to purposefully control ARGs carried by pathogenic hosts and mobility.

Full-Scale Sewage Sludge Reduction Technologies: A Review with a Focus on Energy Consumption

In recent years, increasing attention has been paid to the problem of sewage sludge management and the relevant energy consumption, which represent the main cost items in wastewater treatment plants. Therefore, implementation of technologies that can reduce sludge production and ensure a positive impact on the energy of the entire sewage treatment plant has gained considerable importance in the scientific and technical community. The objective of this study was thus to screen full-scale sludge reduction technologies integrated into both the water line and the sludge line of a municipal sewage treatment plant with a sustainable impact on the overall balance of the plant. The results showed that, within the water line, ultrasound in the recirculation line of the activated sludge allowed for greater reductions in sludge production than the Cannibal and UTN systems, despite the higher energy consumption. CAMBITM, BioThelysTM, ExelysTM and TurboTec® enabled the greatest reductions in sludge production among the technologies integrated into the sludge line, and although they required a large amount of energy, this was partially offset by energy recovery in terms of additional biogas production.

Comparison of Dissolved Organic Matter Composition and Microbial Distribution between Distributed-Inflow Biological Reactor and Two-Stage Anoxic/Aerobic for Piggery Wastewater Treatment

Piggery wastewater contains high amounts of feces, carbon, nitrogen, phosphorus, and other contaminants, introducing serious pollution into water, soil, and the atmosphere. Biological treatment technology is widely used in large-scale pig farms because of its high efficiency and economical advantages. In this study, two typical biological treatment systems—a distributed-inflow biological reactor (DBR) and a two-stage anoxic/aerobic (A/O/A/O)—were adopted to treat piggery wastewater to compare the treatment performance, the dissolved organic matter (DOM) composition, and the microbial distribution characteristics. The results show that the A/O/A/O system had better removal performance in terms of chemical oxygen demand (COD) compared to the DBR system, and similarly effective at removing and ammonia nitrogen (NH4+-N) and total nitrogen (TN). Using parallel factor analysis of the fluorescence excitation–emission matrix, four DOM components—namely fulvic acid-like/humic-like substances (C1), tyrosine-like substances (C2), humic-like substances (C3), and tryptophan-like substances (C4)—were tracked in piggery wastewater. Protein-like substances were significantly degraded, while humic-like substances were difficult for microorganisms to utilize. The endogenous input and humus characteristics of effluents were enhanced. Bacteroidetes (43.9% and 37.5% ) and Proteobacteria (43.1% and 56.7%) are the dominant bacteria in DBR and A/O/A/O systems. The microbial metabolites in DBR and A/O/A/O systems are mainly composed of amino acids, sugars, alcohols, and other small molecules, while those in the municipal sewage treatment plant system is mainly composed of ketones, amines, acids, lipids, and other small molecules. The results of microbial communities and metabolites can help to trace the process of biological systems treating piggery wastewater.

Основные стимулы для использования сточных вод в целях орошения: лучшие мировые практики

Purpose: to determine the key incentives for developing irrigation in the regions of the country with a clear shortage of water resources through the use of domestic wastewater discharged from municipal sewage treatment plants. Discussion. The use of domestic wastewater for irrigation has been practiced by ancient civilizations. In modern realities, as earlier, irrigation with domestic wastewater and water of varying degrees of purification is most widely practiced by farmers and other consumers having land near municipal sewerage systems, which makes it easier to transport irrigation water and reduce financial costs for their post-treatment. In order to promote social and environmental policies on efficient wastewater disposal, various motivating mechanisms are used. The main positions that should be taken into account in the case of planning wastewater irrigation are highlighted. The data on using wastewater for irrigation in foreign practice are presented, the motivating mechanisms used to stimulate such usage and the current Russian and foreign standards used to assess the quality of treated wastewater are highlighted. In Russia, no additional incentive mechanisms for wastewater post-treatment of in irrigated fields are used. The main incentive is the ability to avoid payments and fines for discharge of wastewater of inadequate quality. Such an incentive works only for enterprises that carry out the removal and treatment of domestic wastewater, and there are no incentives for Russian farmers to develop wastewater for irrigation. Conclusions. Of particular importance are the financial indicators and economic benefits for the parties involved in the implementation of the process of irrigating crops with treated wastewater. If we focus on the international experience of motivating incentives, it is of particular interest to vary the payment for irrigation water depending on its quality and consumption amount.

Modeling and optimizing of an actual municipal sewage plant: A comparison of diverse multi-objective optimization methods

The activated sludge process of an actual municipal sewage treatment plant was systematically modeled, calibrated, and verified in this study. Identified multi-objective optimization (MOO) methods were employed to optimize the process parameters of the validated model, and the optimal MOO algorithm was obtained by comparing Pareto solution sets. The optimization model consisted of three key evaluation indicators (objective functions), which are the average effluent quality (AEQ), overall cost index (OCI), and total volume (TV) of the biochemical tank, along with 12 more process parameters (decision variables). Three optimization algorithms, i.e., adaptive non-dominated sorting genetic algorithm III (ANSGA-III), non-dominated sorting genetic algorithm II (NSGA-II), and particle swarm algorithm (PSO), were adopted using MATLAB. The comparison of these algorithms demonstrated that the ANSGA-III algorithm had better Pareto solution sets under the triple objective optimization, and the effluent quality of COD, TN, NH4+-N, and TP after optimization decreased by 2.22, 0.47, 0.13, and 0.02 mg/L, respectively. Additionally, the simulated AEQ was reduced by 13% compared to the original effluent, and the OCI and TV decreased from 21,023 kWh d−1 and 17,065 m3 to 20,226 kWh d−1 and 16,530 m3, respectively. The reported ANSGA-III algorithm and the proposed multi-objective method have a promising ability for energy conservation, emission reduction, and upgrading of municipal sewage treatment plants.

Direct, automated and sensitive determination of glyphosate and related anionic pesticides in environmental water samples using solid-phase extraction on-line combined with liquid chromatography tandem mass spectrometry

An automated procedure for the simultaneous determination of six anionic pesticides, including glyphosate (GLY) and its transformation product aminomethylphosphonic acid (AMPA), was developed and applied to the analysis of environmental water samples. The proposed method combines on-line concentration of water samples (0.160 mL), with compounds separation in an anion-exchange liquid chromatography (LC) column, followed by their selective determination by tandem mass spectrometry (MS/MS). The global procedure was completed in 25 min, providing limits of quantification (LOQs) between 5 ng L−1 and 20 ng L−1, with reduced effect of the surface water matrix in the efficiency of process (SPE and ionization yields). The method was applied to the analysis of grab samples obtained from three watersheds, in two rural and one residential area, in Galicia (Northwest Spain). Out of six investigated compounds, Fosetyl, AMPA and GLY were noticed in the set of processed samples. Their detection frequencies increased from 12% (Fosetyl) to 88% (AMPA). Median concentrations followed the same trend varying from 9 ng L−1 (Fosetyl) to 44 ng L−1 (AMPA). The higher levels and the large seasonal variations in the residues of the latter species were noticed in small rivers affected by discharges of municipal sewage treatment plants (STPs).