Treated Sewage Effluent Research Articles

Ecotoxicological effects of pharmaceutical preparations and the possibility of removing them through phytoremediation: A review

From several decades, there was a significant increase in the production of pharmaceuticals due to their widespread use for both animal and human health. However, these pharmaceuticals also release large amounts of waste into the water environment, where they have been found at levels of ng/l to mg/l in wastewater and surface water. Additionally, because pharmaceuticals initially have biological effects such endocrine disruption, they may have a multitude of adverse effects. Hospitals are indicated or thought to be a significant and extremely variable source that is typically released into sewers immediately, without any kind of preparation. even if they only make up a minor portion of the influents of sewage treatment plants' overall effluent volume. One of the primary sources of pharmaceuticals that are present in every area of the environment is the hospitals. These medications were transferred to wastewater treatment plants (WWTPs), which lack the necessary equipment to effectively handle these kinds of substances. Pharmaceutical contamination of water is regarded as a growing pollution issue in developed nations as these pollutants and micropollutants have been introduced into drinking water sources. In order to raise awareness among physicians, patients, and pharmaceutical manufacturers that pharmaceutical materials may have side effects outside of the patient, certain countries have implemented a classification system for pharmaceutical drugs based on their propensity to accumulate in surface water and interfere with aquatic life. This program is assessed by yearly tests of pharmaceuticals in sewage treatment effluents. The results indicate the presence of numerous types of medicines, including trimethoprim, sulfamethoxazole, and metronidazole, in all analyzed sewer treatment plant effluents. The manufacturing and consumption of pharmaceuticals appear to have an impact on their presence in wastewater.

Soil chemical characteristics, yield and technological quality of sugarcane under subsurface drip irrigation with treated sewage effluent

ABSTRACT Sugarcane cultivation requires sustainable strategies to meet water and nutritional needs. This study tested the hypothesis that irrigation with treated sewage effluent (TSE) can meet the water needs of sugarcane plants, improving their technological quality and yield. The objective of this study was to assess the effects of subsurface drip irrigation (SDI) with TSE or surface reservoir water (SRW) on soil chemical characteristics and technological quality and productivity. Thus, an SDI system was installed at soil depths of 0.20 and 0.40 m to apply SRW and TSE to sugarcane plants, composing four irrigation treatments (TSE0.2 m, TSE0.4 m, SRW0.2 m and SRW0.4 m) and a control (non-irrigated treatment). Analyses of soil chemical characteristics in different layers showed no negative effects for the use of SDI, which maintained favorable soil conditions for sugarcane plantations. The surface layer (0–0.2 m) irrigated with SRW or TSE showed higher accumulation of nutrients and organic matter. The results confirmed the hypothesis that irrigation with TSE or SRW improves the technological quality and yield of sugarcane; the treatment TSE0.2 m showed the best results regarding increases in sugar yield and alcohol production. However, continuous monitoring of soil salinity is necessary in wastewater-irrigated agricultural systems.

Bi-functional NiFe2O4/SrTiO3 S-scheme heterojunction for eminent performance photocatalytic treatment of sewage effluent and electrochemical hydrazine determination

Devising of materials that afforded dual applicability in decontamination and pollutant detection were still a towering challenge owing to the increasing flux of discharge toxic contaminants over the years. Herein, the NiFe2O4 nanoparticles-loaded on cube-like SrTiO3 (NiFe2O4/SrTiO3) composite was fabricated by a two-step hydrothermal approach providing remarkable photocatalytic treatment and electrochemical sensing of noxious pollutants in wastewater. The material traits of the fabricated composite were scrutinized by myriad characterization approaches. The NiFe2O4/SrTiO3 hybrid material demonstrated high surface area of 19.81 m2/g, adequate band gap energy of 2.75 eV, and prominent photoluminescence characteristics. In the presence of visible light, the NiFe2O4/SrTiO3 exhibited profound photocatalysis capability to eliminate sewage effluent-bearing chlortetracycline hydrochloride (CTCH) with 88.6% COD removal in 120 min, outperforming other pure materials. Meanwhile, the toxicity examination of effluent, the possible degradation pathway of CTCH and the proposed photocatalysis mechanism were also divulged. More importantly, the glassy carbon electrode was modified with synergized NiFe2O4/SrTiO3 (NiFe2O4/SrTiO3−GCE) was adopted for the precise quantification of Hydrazine (Hz). The NiFe2O4/SrTiO3−GCE obeyed first-order response for the Hz detection within the range of 1–10 mM: cyclic voltametric: limit of detection (LOD) of 0.119 μM with sensitivity of 18.9 μA μM−1 cm−2, and linear sweep voltametric: LOD of 0.222 μM with a sensitivity of 12.05 μA μM−1 cm−2. The stability and interference of modified electrode were also inspected. This work furnished valuable insights to yield a composite with the prominent S-scheme heterojunction system for quenching of charge carrier recombination and consequently contributing to the future realization into the domains of environmental clean-up and toxic chemical detection.

Multilevel assault dominated by electron-transfer nonradical pathway via electronic metal–support interactions of Bi-C bonds for disinfection

Multilevel assaults on aqueous pathogenic microorganisms were realized by persulfate (PS) activation system with Bi–C based electronic metal-supported interactions (EMSI) of bismuth-embedded carbon chainmail catalyst (Bi@CC) dominated by electron-transfer nonradical pathway. The Bi@CC/PS disinfection system achieved approximately 100 % bacterial inactivation (6.5 log10 cfu/mL) within 35 min. The electron transfer from Bi to the carbon layer via Bi-C bond leading to higher work functions, thus realizing primary assault to the extracellular membrane via bacterial extracellular electron transfer (EET) function. Electron rearrangement of Bi-C is conducive to forming the intermediate complexes (Bi@CC-PS*), leading to higher work functions and enhancing electron transfer pathway (ETP) process to aggravate cell destruction, while radicals (∙OH andSO4∙-) directly attacks the interior cell. The Bi@CC/PS disinfection system possesses excellent environmental adaptability, cycling performance, and safety. This study enriches the heterogeneous mechanism of PS activation and proposes a promising strategy for sewage effluent treatment.

Application of Low-Pressure Nanofiltration Membranes NF90 and NTR-729HF for Treating Diverse Wastewater Streams for Irrigation Use

The application of low-pressure nanofiltration (NF) was investigated for three different applications: water reuse from acid mine drainage (AMD), surface water containing natural organic matter (NOM) and agricultural reuse of microfiltered biologically treated sewage effluent (MF-BTSE). AMD contains many valuable rare earth elements (REEs) and copper (Cu) that can be recovered with fresh water. The NF90 membrane was investigated for recovery of fresh water from synthetic AMD. A steady permeate flux of 15.5 ± 0.2 L/m2h was achieved for pretreated AMD with over 98% solute rejection. NF90 achieved a high dissolved organic carbon (DOC) rejection of 95% from surface water containing NOM where 80% of the organic fraction was hydrophilic, mainly humics. The NF process maintained a high permeate flux of 52 LMH at 4 bars. The MF-BTSE was treated by NTR-729HF for agricultural reuse. NTR-729HF membranes were capable of rejecting DOC and inorganics such as sulfates and divalent ions (SO42−, Ca2+ and Mg2+) from MF-BTSE, with less than 20% rejection of monovalent (Na+ and Cl−) ions. The sodium adsorption ratio (SAR) was significantly reduced from 39 to 14 after treatment through NTR-729HF at 4 bar. The resulting water was found to be suitable to irrigate salt-sensitive crops.

Multi-period optimization of water planning for a sustainable agriculture: carbon footprint and water footprint assessment

Abstract The State of Qatar has undergone significant changes impacting water resources in recent years, with rapid population growth being a significant factor. The government has implemented several policies and initiatives to manage water resources effectively, including introducing a water conservation strategy investing in desalination plants and wastewater treatment facilities. However, the expansion of the agricultural sector has driven up demand for water resources, placing additional pressure on limited supplies. Effective decision-making processes are crucial to sustainable water resource management, particularly in water-scarce countries, and multi-period optimization is an important tool for such decision-making. This study presents a five-year period for multi-period optimization of water planning in the agricultural sector to consider short-term and medium-term dynamics. The aim is to minimize the carbon footprint associated with agricultural water allocation, and assess water pollution using the Water Quality Index grey water footprint indicator. The water budget considered includes desalinated water, brackish groundwater, and treated sewage effluent, while the agricultural sector comprises dairy, egg and poultry, red meat production, outdoor farming, and indoor farming. Considering the water conservation importance in the State of Qatar, the three levels of water stress that were considered are 0%, 25% and a base scenario carbon footprint-based water stress. The latter is calculated such that the improved scenario’s carbon footprint is lower than that of the base scenario while keeping a safe annual water stress. Results show that it possible to reduce the water stress from an unsafe average to as little as 13.7%. Similarly, the water pollution estimated using the grey water footprint method is significantly lower compared to the base scenario.

Performance evaluation of pilot phyto-vortex integrated system in the reduction of wastewater pollutants

Abstract Wastewater pollution remediation connects to goal 6 of the United Nations 17 Sustainable Development Goals (SDG) ensuring availability and sustainable management of water and sanitation for all. Conventional and advanced wastewater treatment are quite expensive to operate to fully comply with regulatory standards in the country. Phyto-vortex integrated system is an alternative tertiary wastewater treatment system that interfaces with an oil and grease skimmer and vortex technology, relying on green plants and a variety of soil substrates to remediate wastewater. The research evaluated the potential of the Phyto-vortex system and its performance in the reduction of domestic wastewater pollutants. Plants and soil substrates were selected via Analytic Hierarchy Process (AHP) using one-way sensitivity analysis. Common reed, Vetiver grass, and Canna Lily were planted in constructed reed beds with various soil matrices using substrates laid at different levels. The beds operate continuously as a horizontal subsurface flow treating 5 m3 of a sewage treatment effluent per day with 1-3 days hydraulic retention time (HRT). The vortex unit aerates the water for further removal of gaseous pollutants. Samples were taken at designated points for 18 weeks. Analysis of the results shows a maximum reduction of 92% for biochemical oxygen demand (BOD), 60 % for chemical oxygen demand(COD), and 70 % for total suspended solids (TSS). Concentration of identified heavy metals in the influent are within the regulatory standards except for a rise in zinc concentration which was 97% reduced in the system. The percentage reduction of pollutants varies each week with nitrates decreasing in the range of 50% to 99%, phosphates from 8% to 39.5%, and ammonia from 45.65% to 99%. Varying environmental conditions such as monsoon rains and extreme heat caused algal blooms and plant disease affecting the results. Lower temperatures and lower humidity favor a decrease in the levels of the pollutants while higher temperature, higher humidity favor an increase in the levels of Nitrates, Phosphates, and Ammonia. The overall results show an effective integrated system of phytoremediation coupled with a vortex unit in the reduction of wastewater pollutants.

Innovative stimuli-responsive membrane MSF brine rejection dilution by tertiary treated sewage effluent

In this study, treated wastewater and Multi-Stage Flash (MSF) brine were integrated into the Forward Osmosis (FO) system using pressure stimuli-responsive Nanofiltration (PSRNF) membranes to dilute magnesium, calcium, and sulfate MSF plant brine reject. The deposition of magnesium sulfate and calcium sulfate in the heat exchanger is one of the main issues affecting the performance and efficiency of MSF thermal desalination plants. Reducing the concentration of the divalent ions can minimize scale formation and deposition to a level that allows the MSF plant to operate at high top brine temperature (TBT) and without scale problems. The PSRNF membranes were chosen in the FO process because of their high water permeability, rejection of divalent and monovalent ions, small structure parameter (S), and inexpensiveness compared to commercial FO membranes. Three PSRNF membranes were tested in the FO process with the feed solution facing the active membrane layer to avoid active layer delamination. Although the PSRNF membrane exhibited negligible water flux at 0 bar, it increased when a 2–4 bar was applied to the feed solution. The wastewater temperature was set at 25 °C while 40 °C was the brine operational temperature to mimic the field situation. A maximum average water flux of 39.5 L/m2h was recorded at 4 bar feed pressure when the PSRNF membrane was used for the brine dilution, achieving up to 42% divalent ions dilution at 0.02 kWh/m3 specific power consumption. The average water flux in the PRSNF membrane was 35% higher than that in the commercial TFC FO membrane. Notably, the PSRNF membrane is ten times cheaper than commercial FO membranes. Notably, the PSRNF membrane is ten times cheaper than commercial FO membranes, achieving substantial cost reductions and pioneering advancements in FO purification technology.

Elucidating the function of MgO precursors on the adsorptive removal and recovery of water phosphorus

Phosphorus (P) recovery with MgO-based adsorbents (MBA) is an effective method for water management and eutrophication prevention. However, the function of MgO precursors on the adsorptive removal and recovery of water P has not yet been sufficiently studied. Therefore, five distinct precursors, namely MgCl2·6H2O, Mg(NO3)2·6H2O, Mg(CH3COO)2·4H2O, Mg(OH)2, and Mg5(OH)2(CO3)4·xH2O, were employed to synthesize MgOs, resulting in the formation of corresponding calcination products identified as CH-MgO, NI-MgO, AC-MgO, HY-MgO, and BC-MgO, respectively. The surface morphology, Brunauer-Emmett-Teller specific surface area (SBET), total pore volume (TPV) and average pore size (APS) of the MgOs were impacted by their precursors, which affected their ability for P recovery. The flower-like BC-MgO showed the highest adsorption capacity (mg P/g) for P (426.2), followed by AC-MgO (398.1), CH-MgO (329.5), HY-MgO (296.6), and then NI-MgO (274.9). BC-MgO recovered 56.2 % of total P (TP) and 61.7 % orthophosphate (ortho-P) from livestock wastewater, and 56.3 % TP and 95.9 % ortho-P from sewage treatment effluent. P adsorption was pH dependent and positively correlated with the adsorbents SBET and TPV. Surface complexation and deposition, ligand exchange, and electrostatic attraction were the main processes involved in P adsorptive capture and its recovery. The leaching of Mg2+ into water was negligible from all studied MgOs, particularly BC-MgO and AC-MgO. The recovered P from the P-loaded BC-MgO enhanced seed germination and root growth and thus might be used in soil as an alternative P fertilizer. Based on those findings we can conclude that BC-MgO showed high potential applications for the removal and recovery of P from wastewater under wide range of water pH and therefore can be used for remediation of P-rich water. Those results are meaningful for MBA engineering application, preventing water eutrophication, producing alternative P fertilizers, and achieving sustainable development goals in future.

Effects of Irrigation with Treated Sewage Effluent on the Chemical Characterstics of Soil under the Cultivation of Ground Cover Plants (Case Study: Parand City)

Effects of Irrigation with Treated Sewage Effluent on the Chemical Characterstics of Soil under the Cultivation of Ground Cover Plants (Case Study: Parand City)

Ultrasound, Hydrogen Peroxide, and Persulfate in Hybrid Advanced Oxidation Processes(AOPs): A Comparative Study for the Reuse of Sewage Treatment Effluent

Objectives : As the variety and quantity of recalcitrant pollutants such as pharmaceuticals, pesticides, endocrine disruptors, and cosmetic products discharged into water bodies steadily increase, the need for AOPs following biological wastewater treatment processes is growing. In this study, we compared the Total Organic Carbon (TOC) removal capabilities of conventional AOPs, ultrasound, hydrogen peroxide, and persulfate-based multiple AOPs on the final effluent of S wastewater treatment plant. The study also evaluated the feasibility of wastewater reuse by examining the optimal operating conditions of the applied AOPs.Methods : The removal characteristics of TOC were investigated based on reaction time, US frequency, and oxidant dosage for the following conditions: ultrasound (US) alone, individual treatments with hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>) and persulfate (PS) as oxidants, combined US/H<sub>2</sub>O<sub>2</sub> and US/PS dual AOPs, and a US/PS/H<sub>2</sub>O<sub>2</sub> multi-AOPs system.Results and Discussion : Only US oxidation treatment at 80 kHz for 60 minutes resulted in a 14.4% TOC removal efficiency. Individual treatment with H<sub>2</sub>O<sub>2</sub> at 174 mM showed 69.2% removal efficiency, while persulfate oxidation treatment at 43.5 mM showed 13.8%. The PS/H<sub>2</sub>O<sub>2</sub> oxidation treatment showed 68.5% removal efficiency at 174 mM H<sub>2</sub>O<sub>2</sub> and 0.52 mM PS, and an 85.3% removal efficiency at 2.08 mM PS and 350 mM H<sub>2</sub>O<sub>2</sub> conditions. Under the same 80 kHz ultrasound conditions, the combined US and other oxidant treatment resulted in an increased TOC removal efficiency: 87.8% for US/H<sub>2</sub>O<sub>2</sub> at 174 mM H<sub>2</sub>O<sub>2</sub>, and 81.9% for US/PS at 43.5 mM PS. Additionally, the multi-treatment with US, PS, and H<sub>2</sub>O<sub>2</sub> showed a removal efficiency of 87.0% at 2.08 mM PS and 350 mM H<sub>2</sub>O<sub>2</sub>, and 91.1% at 174 mM H<sub>2</sub>O<sub>2</sub> and 0.52 mM PS conditions.Conclusion : In this study, among the AOPs, the oxidation treatment with US/PS/H<sub>2</sub>O<sub>2</sub> exhibited the highest TOC removal efficiency at 91.1%. The integration of chemical oxidants with US demonstrated significant improvement in TOC removal capabilities, with PS showing superior performance at the same concentration conditions among the utilized chemical oxidants in the multi-AOPs. Although H<sub>2</sub>O<sub>2</sub> also displayed commendable TOC removal abilities, its oxidation efficiency was lower at low concentration injections, whereas higher concentrations of H<sub>2</sub>O<sub>2</sub> injections proved to be more effective in oxidation.

Nutrient dynamics in wetland systems associated with hydrological and anthropogenic variations in the south of Samborombón Bay, Argentina

Wetlands provide numerous ecosystem services to the environment, such as nutrient removal and storage. The aim of this work is to evaluate the nutrient dynamics in different sectors within wetland systems in the south of the Samborombón Bay (Argentina) based on hydrological and/or anthropogenic variations. For this purpose, the hydrological features of the wetland were defined through the analysis of satellite images, precipitation and tidal data, and field surveys. Three sectors were identified in the wetland: one with tidal influence, another which is dependent on rainfall, and another that receives inputs from rainfall and from a sewage effluent treatment plant. In order to analyze the nutrient dynamics, samples of surface water, groundwater, and sediments were collected from these sectors. Measurements of pH and electrical conductivity were determined in situ in water samples, while the concentration of inorganic forms of phosphorus and nitrogen, soluble reactive silica, and organic carbon were determined through laboratory analysis. Also, bioavailable phosphorus, organic matter, pH, and electrical conductivity were determined in the sediment samples collected. Statistical analysis of the data reveals differences between the sectors and allows the interpretation of the dynamics of the studied components in the wetland. Electrical conductivity distinguishes the intertidal sectors of the wetland while components associated with P and N discriminate the sectors with inputs from the sewage effluent treatment plant. On the other hand, soluble reactive silica, organic carbon, and organic matter do not seem to be influenced by the tide or effluent discharge. This study demonstrates that the studied wetland works as a nutrient retention area, providing ecosystem services to local inhabitants. Although these services can be utilized, they require a continuous monitoring over time to provide an early warning in case the variations in P and N cycles could lead to eutrophication or wetland degradation.

How Does Irrigation with Wastewater Affect the Physical Soil Properties and the Root Growth of Sugarcane under Subsurface Drip?

Studies on the development of the root system can provide important information about responses to different management strategies, such as the use of lower quality water, also evaluating the interaction between plants and the physical properties of the soil. This study tested the hypothesis that irrigation with treated sewage effluent (TSE) supplies the water needs of sugarcane plants, increasing root growth and improving the physical properties of the soil. We evaluated the effects of subsurface dripping with TSE or surface reservoir water (SRW) on the root development of first ratoon cane (Saccharum officinarum L.) and the physical properties of dystrophic red latosol. Irrigation treatments were applied at 20 and 40 cm and soil properties were evaluated at soil depth layers of 0–20, 20–40, 40–60, and 60–80 cm. We verified that under irrigation with TSE and SRW, shallower soil layers present better porosity, soil aggregation, and aggregate stability conditions, parameters that improve the root system development and plant growth. On the other hand, deeper soil layers have lower macroporosity and higher total clay volume, indicating the possibility of compaction and greater limitations for sugarcane root growth. These results are important for understanding soil quality and provide significant information for agricultural management and for the implementation of sustainable soil conservation practices. This study shows the efficiency of TSE as an alternative water source for sugarcane crops.

The Effect of Irrigation With Treated Sewage Effluent of Parand City on Growth Traits and Concentration of Nutrients (N, P and K) in Three Cover Plants

The Effect of Irrigation With Treated Sewage Effluent of Parand City on Growth Traits and Concentration of Nutrients (N, P and K) in Three Cover Plants

Campylobacter Species: New Insight, Clinical Diagnosis and Laboratory Approach

Campylobacter, a prevalent cause of global gastroenteritis, has exhibited an escalating impact worldwide, affecting both industrialized and developing nations. Even though Campylobacter jejuni and C. coli are the main causes of infection, new pathogens make it imperative to comprehend the disease mechanisms, dynamics of transmission, and evolution of less-studied species. Accessible whole-genome sequences obtained through high-throughput sequencing have made it easier to conduct in-depth pathogenomic studies, particularly on species such as C. fetus and C. concisus. These studies have shown novel applications in clinical microbiology by revealing genomic traits associated with pathogenicity and offering insights into the evolutionary mechanisms shaping their genomes. Effective pathogen management urgently requires deeper understanding of the evolution of pathogenicity in emerging Campylobacter species are urgently required for effective pathogen management. This comprehensive review synthesizes existing knowledge and outlines future research directions in this crucial field. The Gram-negative, non-spore-forming, curved or spiral rods known as campylobacters include a "thermophilic group" that is important to the water industry and includes C. jejuni, C. coli, and C. upsaliensis. Acute diarrhea is the usual symptom of a human Campylobacter infection, and key virulence factors have been identified as antibiotic resistance genes and flagellar DNA. Many campylobacters are frequently found in sewage and treated sewage effluents, whereas surface waters are less contaminated. Testing for Campylobacter prevalence through epidemiological methods requires a careful balance between phenotypic and genotypic data. Campylobacters are sensitive to oxygen, but they have strong survival strategies that may involve the formation of biofilms. Methods of inactivation that work well for coliforms are thought to be appropriate for Campylobacter. In addition to providing a synthesis of current knowledge and identifying future research directions to advance strategies for the effective management and mitigation of Campylobacter-related infections, this thorough review highlights the urgent need for additional research to deepen our understanding of these pathogens. The investigation of genetic features linked to pathogenicity, dynamics of transmission, and survival strategies highlights the complex character of Campylobacter infections. The dynamic nature of Campylobacter as a primary cause of gastroenteritis necessitates continued research endeavors to guide focused interventions and lessen the worldwide impact of this grave public health issue.

Photocatalytic Degradation of Pharmaceutical Residues from Water and Sewage Effluent Using Different TiO2 Nanomaterials.

Pharmaceuticals are widely used and often discharged without metabolism into the aquatic systems. The photocatalytic degradation of pharmaceutical compounds propranolol, mebeverine, and carbamazepine was studied using different titanium dioxide nanostructures suspended in water under UV and UV-visible irradiation. Among three different photocatalysts, the degradation was most effective by using Degussa P25 TiO2, followed by Hombikat UV100 and Aldrich TiO2. The photocatalytic performance was dependent on photocatalyst dosage, with an optimum concentration of 150 mg L-1. The natural aquatic colloids were shown to enhance the extent of photocatalysis, and the effect was correlated with their aromatic carbon content. In addition, the photocatalysis of pharmaceuticals was enhanced by the presence of nitrate, but inhibited by the presence of 2-propanol, indicating the importance of hydroxyl radicals. Under optimum conditions, the pharmaceuticals were rapidly degraded, with a half-life of 1.9 min, 2.1 min, and 3.2 min for propranolol, mebeverine, and carbamazepine, respectively. In treating sewage effluent samples, the photocatalytic rate constants for propranolol (0.28 min-1), mebeverine (0.21 min-1), and carbamazepine (0.15 min-1) were similar to those in water samples, demonstrating the potential of photocatalysis as a clean technology for the effective removal of pharmaceuticals from sewage effluent.

Successful Water Quality Improvement Practices of a Campus’s River in Ningbo Based on Water Replenishment and Circulation Since Year 2017

Rivers play a critical role in regional water quality, but from time to time concentration of surface water pollutants can easily exceed both national and local water standards. This study debates the feasibility and effectiveness of utilizing the natural treatment potential of flowing river water by replenishing treated sewage effluent and forced circulating. The research combines field experiments and laboratory analyses to assess the impact of this approach on water quality. Theoretical simulation with one-dimension modeling recommended by China’s national standard of “Code of Practice for Computation on Allowable Permitted Assimilative Capacity of Water Bodies” (GB/T 25173-2010) indicates that the target campus river water’s cycle flowing contributes to the further removal of key pollutants from treated sewage, resulting in the improvement of campus river’s water quality downstream along its forced circulation. NH3-N and CODMn levels of the campus’s river water were notably reduced and met the planning water qualities as expected.

Развитие методики расчёта нормативов допустимого сброса жидких производственных отходов с учётом региональных особенностей водных объектов

The problem of regulating the discharge of liquid wastes into water bodies is the most urgent task and is carried out on the basis of establishing standards of permissible discharge (SPD). Many authors note that the key problem of setting the SPD is the use of maximum allowable concentrations (MAC) as threshold values, determined without taking into account regional peculiarities of formation of natural water composition and its ability to dilute wastewater. We have proposed the development of the methodology for calculating SPD, based on the condition that ensuring the disposal of liquid wastes at the level of permissible discharge standards will not lead to a change in the water quality class determined using the specific combinatorial index of water pollution (SCIWP). In the previous publication we have substantiated territorial threshold concentrations (TTC) based on the analysis of long-term data sets of hydrochemical observations, which allow us to take into account regional features of the geochemical background of water bodies, including the content of substances of dual genesis. They also implicitly allow taking into account hydrological and hydrochemical factors that ensure the ability of natural waters to dilute liquid waste effluents. The obtained TTCs are proposed to be used for calculation of permissible concentrations of substances in wastewater instead of MAC. SPD is established by cyclic iteration of TTC values by 10%, with parallel calculation of SCIWP, until the index is transferred to another water quality class. This paper presents the results of approbation of the proposed development of the methodology of SPD calculation for liquid waste from Оpen JSC “Kazan Synthetic Rubber Plant” discharged into the Volga River. The obtained calculation results make more stringent requirements to the value of SPD for substances mainly of anthropogenic origin. For some substances of dual genesis, the value of SPD was higher, which allows us to make more adequate requirements to water users for treatment of sewage effluents.

The combined effects of treated sewage discharge and land use on rivers.

Freshwater ecosystems are increasingly threatened by multiple anthropogenic stressors. Release of treated sewage effluent and pollution from agricultural or urban sources can independently reduce water quality with implications for ecological communities. However, our knowledge of the combined effects of these stressors is limited. We performed a field study to quantify the combined effect of treated sewage discharge and land use on nutrient concentrations, sewage fungus presence and communities of macroinvertebrates and benthic algae. Over three seasons in four rivers we found that a model which included an interaction between sewage pollution and time of the year (i.e. months) was the best predictor of nutrient concentrations and the abundance of algae and sewage fungus. Both macroinvertebrate and algae communities shifted downstream of sewage input. Specifically, more tolerant groups, such as cyanobacteria and oligochaetes, were more abundant. The EPT (Ephemeroptera, Plecoptera and Tricoptera) water quality score was best explained by an interaction between month and agriculture in the surrounding landscape. Overall, our results show that sewage discharge has a significant impact on water quality and benthic riverine communities, regardless of the surrounding land uses. Agricultural inputs, however, could be more important than treated sewage discharge in reducing the abundance of sensitive invertebrate taxa. We need both improvements to wastewater treatment processes and reductions in agricultural pollution to reduce threats to vulnerable freshwater communities.

Effect of a natural wetland on the removal of antibiotics and antibiotic resistant bacteria in a treated sewage treatment effluent

Antibiotics are often released into the environment via disposal or excretion. A selection pressure is then initiated that leads to the acquisition of antibiotic resistance genes (ARGs) in environmental bacteria, thus encouraging the environmental spread of antibiotic resistance. The purpose of this study was to examine the nutrient and antibiotic reducing capacity of the Point au Chene assimilation wetland that receives the city of Thibodaux, Louisiana, USA treated sewage wastewater. Water samples were collected from four sampling sites along the wetland every month from May 2022 to April 2023. Water quality was assessed at each stage of flow within the wetland including the direct discharge (input) site, wetland midpoint, wetland endpoint, and a control site adjacent to the Thibodaux Sewage Plant, but separated by a hardwood ridge that prevents the intrusion of treated effluent. Standard water quality parameters, coliform bacteria, and antibiotic concentrations were determined. Results indicated antibiotic, coliform, nitrate, sulfate, and ammonia concentrations were significantly higher at the input site than other wetland sites. The antibiotics, tetracycline and sulfamethoxazole were reduced by 75 % in the wetlands. More than 80 % of penicillin and bacitracin were removed throughout the wetland. The input site additionally expressed the highest amount of multi-drug resistance and bacterial diversity of all sites. ARGs have been identified throughout the wetland system, with bacterial isolates testing positive for the ARGs bacA, sul2, and tetA, coding for resistance to bacitracin, sulfonamide, and tetracycline antibiotics respectively. The wetland has a positive impact of reducing the nutrients, antibiotics, and ARB in the treated sewage prior to release to adjacent waterbodies.