Quality Of Treated Wastewater Research Articles

Ensuring Sustainable Agricultural Practices: Treated Wastewater Quality and Its Impact on Groundwater for Irrigation in Oman

Ensuring Sustainable Agricultural Practices: Treated Wastewater Quality and Its Impact on Groundwater for Irrigation in Oman

Study on quality of treated wastewater for urban agriculture use in Addis Ababa, Ethiopia

Non-conventional water supplied from Bole Lemi Industrial Park (BLIP) in Addis Ababa, Ethiopia is treated to remove contaminants, but never has been analyzed for its quality for urban agriculture (UA) use. The objective of this study is to analyze the quality of treated wastewater (TWW) using treated wastewater quality index (TWWQI). Treated wastewater samples were taken at the influent and effluent of the wastewater treatment plant located within BLIP. The physico-chemical properties of the water samples from BLIP were analyzed at the third-party laboratory. The result showed that the aggregate TWWQI value falls under the category of very poor water for urban irrigation agriculture (UIA) use. This very poor water quality grade attributes 85 % to the presence of heavy metals, 4 % to nutrients load, 8 % to saline condition contributors and 4 % to miscellaneous contaminants. Discrete analyses of the indices for heavy metals, nutrient loads, saline condition contributors and miscellaneous contaminants shifted the water quality from very poor to very polluted, excellent, poor and good for UIA use respectively. Though the aggregate TWWQI is of very poor category for UIA use, the treatment plants of BLIP exhibited contaminants removal efficiencies of between 30 and 100 % with aggregate removal efficiency of 58 %. Results also revealed that there were contaminants that exhibited higher effluent values than influent after treatment indicating the failure of BLIP’s treatment plants to remove these contaminants. In conclusion, treated wastewater from BLIP, falls under very poor water category for use in irrigation agriculture where Cr+3, Cl− and TDS have contributed most in that order. Therefore, BLIP should upgrade and optimize its treatment plants to increase the removal efficiency for the respective contaminants. Moreover, BLIP should enhance the capacity of the experts through training and continually monitor the quality of the water to protect the environment and ensure its contribution to the building of a resilient city.

Evaluation of treated wastewater quality from Cap-falcon plant for agriculture irrigation

Wastewater reuse is a useful tool for minimizing the amount of wastewater discharged into the environment. However, it is associated with threats to the environment and public health; consequently, effluent quality assessment is essential prior to reuse. The aim of this study is to assess the physicochemical and microbiological quality of treated wastewater from Cap Falcon wastewater treatment plant for reuse in irrigation. The suitability of treated wastewater from Cap Falcon plant for irrigation was assessed based on its composition and Algerian irrigation water quality standards. The average biochemical oxygen demand (BOD5) and chemical oxygen demand (COD) values decrease from 316 mg/L to 21 mg/L with a mean removal efficiency of 93.0% and from 659 to 40 mg/L with removal efficiency of 93.7% respectively. For total suspended solids (TSS), the concentration at the inlet of the treatment plant is very high but reduces greatly after biological treatment with a removal efficiency over 94.5%. The physico-chemical analyses of treated wastewater samples from the storage reservoir indicated that pH varied from 6.81 to 8.20 with an average value of 7.43, which is slightly alkaline in nature. Electrical conductivity is one of the criteria used to evaluate the suitability of water for agricultural use; the average value was found less than 1500 μS/cm, indicating that the treated wastewater is considered as suitable for irrigation use. On the other hand, microbiological analyses indicate that faecal coliforms are high compared with Algerian water quality reuse standards. Furthermore, the overall quality of tertiary treated wastewater was analyzed by calculating the water quality index. The calculated index for the physicochemical and microbiological parameters was 96, which corresponds to a water quality type “very poor” signifying that this effluent can only be used for restricted irrigation practices.

Development of wastewater quality index as an assessment tool of treated wastewater quality for sea discharge

AbstractThe evaluation of the effluent water quality from wastewater treatment plants is fundamental for human health and aquatic environment considerations. Therefore, this research presents a new and specific water quality index for evaluating the effluent water discharged into the sea by integrating the complex set of wastewater qualities into a single reliable value. Two approaches were utilized for this purpose: experts' opinions and statistical analysis using principal component analysis. In the first approach, the opinions of local experts shortlisted the parameters into six important parameters out of a list of 19 with assigned weights varied from 0.160 to 0.174. In the statistical approach, principal component analysis and correlation analysis reduced the parameters to seven accounting for 75% of the variation in the data. Their weights were calculated based on their eigenvalues and ranged from 0.063 to 0.435. The subindices rating curves were developed based on the Kingdom of Bahrain's legislated standards and the weighted arithmetic mean function was used for the aggregation stage. The established water quality indices were applied to effluents from a local wastewater treatment plant, and the obtained results revealed “Class 1: excellent category” discharge quality maintained throughout the year as per the categories proposed in this work. The developed indices proved their effectiveness and reliability in assessing the treated water. The study provides a comprehensive and reliable assessment of treated water quality, and its approach and outputs could have significant implications globally for ensuring the quality of treated water prior its discharge and promoting sustainable development.

Changes in soil hydraulic and physio-chemical properties under treated wastewater irrigation: A meta-analysis

Treated wastewater (TWW) is increasingly used for irrigation, but its higher salt content compared to conventional water sources can induce soil salinization and sodification. This, in turn, may result in structural degradation and deterioration of soil hydraulic properties. The practice of using TWW for irrigation is not new, and it has long been applied in arid countries, with limited other water resources, while in recent years it is also getting used elsewhere given the worldwide influence on water resources. However, comparing and extrapolating results from existing studies on the use of TWW for irrigation is challenging due to the heterogeneity between experimental setups in terms of water quality, irrigation techniques applied, and pedo-climatic conditions. To explore the effect of TWW quality on soil hydraulic and physio-chemical following TWW irrigation and to examine to what extent these effects are soil type dependent, we compiled a database with results from 24 peer-reviewed studies across different soil types containing information on the link between TWW irrigation, and hydraulic and physio-chemical properties through various measurements. The meta-analysis revealed that application of TWW significantly increases sodium adsorption ratio (on average 71 ± 6%) and electrical conductivity (on average 51 ± 5%) of soil as compared to the use of conventional water source. Overall, there were no significant effects on the soil pore space (bulk density, soil total porosity) or pH. Interestingly, the application of TWW significantly increased soil organic carbon and aggregate stability, potentially even benefiting soil structure. In addition, the organic compounds in TWW also might lead to hydrophobicity. Yet, the effects of TWW on soil hydraulic and physio-chemical properties are not consistent across different TWW types and soil classes. A larger number of studies is required to draw sound conclusions on this topic. Anyway, this analysis already indicated that different soil textures might react differently to TWW irrigation. While in medium-textured soils, salt accumulation was observed and TWW significantly increased soil organic carbon and saturated hydraulic conductivity, fine-textured soils are more prone to clogging and reduced in saturated hydraulic conductivity. We also noticed an impact of the type of TWW, since the degree of treatment has a big impact on the remaining components added to the soils together with the water. Primary TWW, from which settleable and floatable solids are removed, resulted in the highest accumulation of salts and significantly increased soil organic carbon and improved soil aggregate stability. However, the elevated biochemical oxygen demand or chemical oxygen demand in this type of TWW leads to an accumulation of organic materials in the soil, negatively affecting its permeability and reducing soil saturated hydraulic conductivity. This study stresses the need for more standardized experiments quantifying the effect of TWW not only in terms of transfer of contaminants and biosafety, but also an effect on soil quality, and more specifically soil physical quality, especially at the longer term.

Multivariate Statistical Analysis of Dyeing Wastewater Organic Matter Indicators

Objectives:Since 2016, TOC (Total Organic Carbon) has replaced COD (Chemical Oxygen Demand) as an organic indicator for effluent wastewater quality standards. However, the distribution of organic substances by process in wastewater treatment facilities is not properly identified, making it difficult to secure stable treated wastewater quality. Therefore, in this study, we identified the correlation between TOC and existing organic matter indicators in raw wastewater, primary treated, secondary treated, and effluent wastewater for dyeing wastewater.Methods:Samples for each process were collected twice a week, a total of 24 times, from a dyeing wastewater treatment plant located in Y-city, Gyeonggi-do, and organic pollutant indicators (TOC, COD<sub>Cr</sub>, COD<sub>Mn</sub>, BOD<sub>5</sub>) were analyzed. TOC was analyzed by the NPOC (non-purgeable organic carbon) method using TOC-VCHP (Shimadzu, Japan). Using the analysis results, the characteristics of organic pollutants in dyeing wastewater were analyzed. In addition, multivariate statistical analysis was performed using SPSS to analyze correlations between organic pollutant indicators and principal component analysis.Results and Discussion:As a result of multivariate statistical analysis, TOC was inflowed at an average of 574.9 mg/L and treated at 58.2mg/L. In the case of COD<sub>Cr</sub>, COD<sub>Mn</sub>, and BOD<sub>5</sub>, the inflow was 1,644, 448.9, and 440.7 mg/L and was treated at 98.2, 39.7, and 10.8mg/L. When evaluated based on effluent water quality standards, all of them satisfied the Region III standards, but were discharged at a relatively high level compared to the TOC concentration of sewage treatment plants effluent. As a result of comparing correlations between organic matter indicators through Pearson correlation analysis, the inflow raw water shows a high positive correlation with TOC:TCOD<sub>Cr</sub> (r=0.720), TOC:TCOD<sub>Mn</sub> (r=0.636), and TOC:TBOD<sub>5</sub> (r=0.302) showed low correlation. This is reason to be due to the fact that most organic substances in dyeing wastewater are non-degradable substances and have low biodegradability. As a result of principal component analysis of influent, primary treated, and final treated, three main components each (two for final treated) were extracted, with cumulative contribution rates of 80.1%, 83.2%, and 95.6%.Conclusion:Because the properties of wastewater differ greatly depending on the type of leather and chemicals handled at the dyeing factory, the correlation between influent water was low, but the correlation between treated water and treated water was relatively high. The correlation between processes in wastewater treatment facilities also tended to increase toward later processes. It is believed that the above statistical analysis can be used as basic data for effective organic matter management.

Assessment of Rice Husk-Based Activated Carbon as Adsorbent in Domestic Wastewater Treatment

Indiscriminate discharge of wastewater into the environment is of utmost concern, especially in developing countries. This study evaluated the efficiency of rice husk based activated carbon in wastewater samples harvested from a students’ hostel and a restaurant within the Federal University of Technology, Akure. The adsorbent used was produced from rice husk using hydrogen tetraoxosulphate (VI) acid (H2SO4) as the activating agent. The aim of this study was to assess rice husk-activated carbon for the reduction of physicochemical parameters such as hardness, pH, biochemical oxygen demand (BOD), chemical oxygen demand (COD), dissolved oxygen (DO), total dissolved solid (TDS), total suspended solid (TSS), and heavy metals which include chromium (Cr), lead (Pb), manganese (Mn), and iron (Fe). The wastewater samples were treated using activated rice hush ash of particle size (180 µm) at four different doses (30, 35, 40, 45 grams/400 ml). The results showed that the different doses of activated carbon had different removal efficiency. It was observed that the optimum dosage was 40g for DO, COD, BOD, and TDS while 30g was optimum for Hardness. It was also observed that an increase in the concentration of rice husk adsorbent led to an increase in the removal efficiency for the heavy metals (Cr, Mn, Pb, and Fe). The maximum percentage removal of DO, COD, BOD, TDS, and TSS, with rice husk was 21%, 58%, 72%, 21%, and 57% respectively. After the treatment of the domestic wastewater and comparing with the WHO standard, the treated wastewater quality was found to be safe for direct discharge into surface water bodies and irrigation purposes.

Statistical Analysis of Wastewater at Panjapur, Trichy

Abstract This study is carried out to find wastewater quality index in treated wastewater, and Statistical analysis was done in various collected samples in sewage treatment plant, Panjappur, Trichy. This study presents a Statistical analysis of the physicochemical parameters of sewage wastewater. Nearly twenty parameters of two different months were analysed using data from physico -chemical analyses. A Continuous Waste Water Quality Index (CWWQI) was established to gauge the overall state of treated wastewater quality. By taking into account previously set quality limitation norms, the index condenses a substantial number of measured quality characteristics into a single water quality term. To identify treatment process performance, the interdependencies between the variables were determined by using Principal Component Analysis (PCA). This study presents Factor analysis to identify the pollution and its type. The methods and approaches discussed in this study offer a framework for evaluating the monitoring programme for wastewater treatment.

Evaluation of Treated Wastewater Quality for Reuse in the Northern Region of Minas Gerais

Objective: This study aims to analyze the quality of effluents treated at three Wastewater Treatment Plants (WWTPs) in the northern region of Minas Gerais, evaluating reuse potential and proposals. Theoretical framework: The practice of reusing sanitary effluents holds significant economic and environmental importance. It conserves water resources allocated for higher priority uses. When assessed and compliant with regulations, effluents become potential water sources for agriculture and urban squares. The trend towards reusing treated effluents presents an alternative to meet water demands that could be satisfied with lower-quality water. Method: The study conducted laboratory analyses of three COPASA MG sewage treatment plants, referred to as WWTPs I, II, and III, between January 2021 and September 2022. Parameters crucial for effluent reuse, including Biochemical Oxygen Demand (BOD), Electrical Conductivity (EC), Hydrogen Potential (pH), Escherichia coli, Sodium Adsorption Ratio (SAR), and viable helminth eggs, were monitored and evaluated. The feasibility of proposed water reuse methods was assessed by analyzing the quality of treated effluents from the three WWTPs, considering that the treatments adhered to the conditions and effluent discharge standards outlined in Joint Normative Decision COPAM and CERH-MG No. 01 of May 5, 2008 (Minas Gerais, 2008), as well as the reuse parameters defined in Normative Decision CERH-MG No. 65/2020 of June 18, 2020 (CERH-MG, 2020). Results and Conclusion: The findings indicate that the effluents treated in the studied WWTPs are suitable for reuse, with potential corrective measures for non-compliant parameters. This allows for irrigation of urban squares, subject to approval by local authorities, and internal irrigation within interested businesses. Research Implications: This approach is highly relevant for fostering discussions on expanding reuse practices and shaping regulations through legislation, norms, and deliberations. Originality: This study stands out due to its in-depth investigation, ensuring a viable water reuse source for localities facing water scarcity, particularly in the northern region of Minas Gerais. This innovative topic, though less explored in literature, is gaining momentum in environmental discourse, thanks to the potential of effluents for agricultural purposes.

Utilization of treated municipal effluent for irrigating agricultural land in Palestine: The driving factors and existing practices

This article investigates the motivations and practices of using treated wastewater (TWW) to irrigate crop fields in Jenin, Palestine. Around 40 farmers were surveyed for data collection. The results showed that 66% of the farmers grew alfalfa crops while 30% grew fruit trees. The main obstacles the farmers faced before starting to use TWW were disgust (68.2%), worries about the quality of TWW (68.2%), health concerns (63.6%), and concerns about adverse effects on the soil (63.6%). All interviewed farmers considered the establishing and funding of an irrigation project to be the cornerstone for any reuse project. The second most important driving factor was the price of TWW that is 10–25% of the fresh water prices. After reusing TWW for irrigation, 59% of the farmers did not use any fertilizer, but they were not sufficiently aware of the crops’ water needs, nor the nutrients in the TWW. All the fodder-growing farmers abstained from selling their crops before drying. The farmers used the TWW for five to nine months annually. After the TWW was reused, the main positive impacts of the TWW reuse were increased crop yields (77.3%), crops quality (50.0%), and crops marketing (47.7%). On the other hand, the main negative impacts were blocking of the irrigation systems (77.3%) and release of odors (54.5%). After practicing TWW use in crops irrigation, the key factors contributed to the “no difference” index were the effects on human health (100%), soil quality (56.8%), and insects spread (54.5%). Therefore, the results of the study support the decision makers to implement TWW reuse policies for crop irrigation in arid regions with scarce water resources. Monitoring TWW reuse and training farmers and helping them overcome obstacles is essential.

Growers' irrigation practices, knowledge, trust, and attitudes toward wastewater reuse in Lebanon, Jordan, and Tunisia through a food safety lens

Abstract Maximizing water reuse requires addressing legal and regulatory frameworks, but growers’ understanding of water as a vehicle for pollutants and safe practices is vital in this process. A cross-sectional survey of 85 growers in Lebanon, Jordan, and Tunisia explored these factors. Results showed that 70.6% of growers had limited knowledge about the transmission of pathogens, pesticides, and pharmaceuticals to food crops via treated wastewater (TWW). Additionally, 55% of farmers used TWW for irrigation, while 65.9% believed that it poses health risks to consumers when applied to crops eaten raw. A positive attitude toward TWW was a determining factor for maximizing water reuse applications. However, the limited access and unavailability of treatment plants were the primary reasons for not using TWW (32.9%). More concerning, less than half controlled the quality of irrigation water using microbiological tests (32.9%), chemical tests (37.6%), and turbidity tests (29.4%). Meanwhile, only 40% trusted local authorities’ control of TWW quality and 69.4% had no access to regulatory information. The present study showed the importance of prioritizing growers’ awareness of potential risks and establishing the practice of monitoring of water quality indicators and contaminants. These should be at the forefront of water reuse expansion strategies to mitigate associated risks.

Redesigning the Wastewater Treatment Plant for the Tofu Industry in Ledok Kulon Village, Bojonegoro Regency

Currently, the wastewater treatment plant (WWTP) for the tofu industry in Ledok Kulon Village, Bojonegoro Regency uses an anaerobic-aerobic-anaerobic system. However, treated wastewater quality is still over maximum standard. To rectify this, the objective of the study was to technically improve the WWTP so that the treated wastewater could comply with the required quality standards for disposal into the environment. This was achieved without increasing the capacity of the WWTP by changing the function of each unit and modifying the flow patterns of the system. Additionally, the treatment system was altered from an anaerobic-aerobic-anaerobic to an anaerobic-aerobic system. Consequently, the WWTP redesigning calculations showed that the levels of BOD, COD, and TSS produced were 9.65 mg/L, 61.23 mg/L, and 2.16 mg/L, respectively, which met the required quality standards.

Assessment of the application of cladode cactus mucilage flocculants for hot chemical degreasing electroplating wastewater treatment and reuse: process efficiency and storage stability.

Pressures related to urban growth and industrial activities exacerbated by climate change had an impact on water resources in Tunisia. The present study examines the application of cladode cactus mucilage (CCM) flocculants for hot alkaline chemical degreasing Zn-electroplating wastewater treatment and reuse (WWTR). The CCM flocculation process was selected through their environmental benefits, economic facilities, sustainable use of the natural biopolymer product, input biopolymers substitution, and on-site treated wastewater (TWW) reuse and recovery. The alum coagulation and CCM flocculation were performed by the jar test series. The suitability of treated wastewater quality (TWWQ) with alum/CCM was also assessed for reuse purpose in terms of corrosion-scaling indices (RSI, LSI, PSI, AI), oxidation-reduction potential (ORP), and microbiological community growth (Bacillus, Pseudomonas, Mesophilic bacteria and yeasts) for 28 days storage at 25 °C. The total alkalinity removal efficiency reached 95.8% with an optimum dosage of alum + CCM for hot alkaline chemical degreasing wastewater bath rinsing. The results showed that the stability of TWWQ has significantly deteriorated during storage leading to aggressive wastewater, pathogen growth, and biological malodor production which make them unsuitable for reuse. Therefore, there is a need for CCM processing alternatives that preserve the physico-chemical and microbial of TWW properties during storage.

Floating Islands Supported by LED Lighting: an Ecological Solution of Nutrients Removal from Municipal Wastewater?

The aim of the study was to evaluate removal efficiency of nitrogen and phosphorus compounds by floating islands with macrophytes and influence of LED lights imitating the photosynthetically active radiation (PAR) on that effectiveness. Improving removal efficiency is crucial, thanks to ever-tightening legal requirements. Main reason for that is growing problem of eutrophication phenomenon. Nowadays, this problem is visible not only in lakes and ponds but also in water courses and coastal water. Study was conducted during time of 15 weeks. In that time, listed parameters were tested: pH, conductivity, total nitrogen, organic nitrogen, ammonium nitrogen, nitrite nitrogen, nitrate nitrogen, total phosphorus, and phosphates. Each tank was filled with same amount of biologically treated wastewater; ambient temperature and dissolved oxygen concentrations were kept in same range for the time of experiment. Average concentrations of main pollutants in tanks with LED lighting have reached: conductivity, 936 μS/cm; TN, 8.55 mg/dm3; P-PO4, 0.74 mg/dm3; TP, 2.57 mg/dm3. In case of no LED lighting, concentrations of main pollutants have reached: conductivity, 949 μS/cm; TN, 12.85 mg/dm3; P-PO4, 1.28 mg/dm3; TP, 2.54 mg/dm3. Based on observations and analyses, it can be concluded that the use of LED lighting imitating PAR radiation has positive effect on removal efficiency of total nitrogen and phosphates. Data suggests optimal time for treatment with floating islands as 13 weeks, extending that time to 15 weeks leads to degradation of treated wastewater quality instead improving it.Highlights• Floating islands supported with LED lighting are an alternative solution for nutrients removal.• LED light intensifies nitrogen and phosphorus removal from municipal wastewater.• The use of macrophytes in third stage of wastewater purification may result in increased nutrient removal efficiency.

Improving the quality of waste water treatment by flocculation

Flocculation using polyacrylamides is one of the most promising methods of industrial wastewater treatment. The aim of our research was to estimate the efficiency of the use of new types of polyacrylamide-based flocculants for industrial wastewater treatment. The objects of the study were the wastewaters of the enterprise LLC “Saratov Chemical Plant of Acrylic Polymers “ACRYPOL” and several flocculants (water-soluble polymers) obtained on the basis of acrylamide, acrylic acid and chitosan. It was established that the optimal dose of nonionic flocculant H600™ was 5 mg/dm3. Industrial wastewater treatment efficiency was studied on two samples of weakly cationic flocculants (215-2 and 233-2) synthesized in a laboratory way, as well as on a sample of nonionic flocculant H600™. It was found that the tested flocculants had no significant effect on the pH value and the content of sulfate ions in water. Flocculant 233-2 with the highest chitosan content was the best in terms of chemical oxygen demand, dry residue and the amount of suspended solids. Flocculant 215-2 with the lowest chitosan content had a slightly worse performance. The worst of the tested flocculants was the nonionic H600™, which does not contain chitosan.

Performance Evaluation of Wastewater Treatment Plants in El-Fayoum

The present study has been undertaken to evaluate performance efficiency of wastewater treatment plants (WWTPs) in El-Fayoum Markaz, El-Fayoum governorate in Egypt. The wastewater treatment plants using different treatment techniques were Active sludge, Oxidation ponds, Secondary - active sludge and Chemical (nanotechnology) which wastewater samples were collected from both influent and effluent of each plant. The key performance of each plant is estimated based on the treated wastewater quality data. Based on the results, they showed that Old Quhafa (Secondary - active sludge technology) operates with removal efficiencies higher than 80% for biological oxygen demand (BOD), chemical oxygen demand (COD) and total suspended solids (TSS) were established. While Ezbet Ashour accomplished lowest performance efficiency that operates with chemical-nanotechnology. This analysis applied to define a performance measuring plan based on the most important parameters that can be reliable and applicable for any WWTP. The study suggested formula for performance WWTPs that described by the expressing removal efficiencies as relative values or percentages and the remaining fraction. The study recommended that sedimentation units must be cleaned, monitoring frequently of sludge analysis and calculation of building capacity for all WWTPs.

Estimation of Per Capita Loading and Treated Wastewater Quality Index in Sharkia Governorate, Egypt

Estimation of Per Capita Loading and Treated Wastewater Quality Index in Sharkia Governorate, Egypt

Insights into the microbial community of treated wastewater, its year-round variability and impact on the receiver, using cultivation, microscopy and amplicon-based methods

Apart from chemical constituents, wastewater treatment plant (WWTP) effluents also release microorganisms that can be important to the receiving water bodies either from a sanitary point of view, or taking to the account the biogeochemical potential of the recipients. However, little is known about the treated wastewater microbial community, its composition, seasonal changes, functions and fate in the waters of the receiver. Thus, this study presents a synergistic approach coupling new and traditional methods: analytical chemistry, classical microbiology (cultivation- and microscopy-based methods), as well as Next Generation Sequencing and a quantitative real-time polymerase chain reaction (qPCR). The results show that in terms of bacterial community composition, treated wastewater differed from the environmental samples, irrespectively if they were related or unrelated to the WWTP effluent discharge. The canonical correspondence analysis (CCA) taking into account chemical parameters and taxonomical biodiversity indirectly confirmed the seasonal deterioration of the treated wastewater quality as a result of temperature-driven change of activated sludge community structure and biomass washout (observed also by DAPI staining). Despite seasonal fluctuations of total suspended solids and inter-related parameters (such as COD, BOD, TN, TP), the treated wastewater quality remained within current discharge limits. It was due to treatment processes intensively adjusted by WWTP operators, particularly those necessary to maintain an appropriate rate of autotrophic processes of nitrification and to support biological phosphorus removal. This can explain the observed microbiome composition similarity among WWTP effluents at high taxonomic levels. Obtained data also suggest that besides wastewater treatment efficiency, WWTP effluents are still sources of both human-related microorganisms as well as bacteria equipped in genes involved in N-cycling. Their potential of participation in nutrients cycling in the receivers is widely unknown and require critical attention and better understanding.

Treatment of Wastewater of Small Sewerage Facilities

The complexity of treating wastewater of small sewerage facilities lies in the small volumes of treated water, considerable irregularity of their inflow to treatment facilities, inhomogeneity of their composition by hours of inflow to treatment facilities, as well as high requirements for treated wastewater discharged usually into low-power water bodies or to the surface. The treatment facilities should exercise the functions of purifying wastewater from pollutants according to regulatory requirements. A sewerage system and wastewater treatment technology have been considered by the example of the town of Fort-Shevchenko. A technology for purifying similar wastewaters using clarifiers with a sludge blanket formed by activated sludge flakes has been proposed. This technology has been introduced at several treatment facilities in the East Kazakhstan region that are successfully operating in compliance with the technical and engineering operation requirements. The treated wastewater quality indicators are given.

Assessment of Municipal Treated Wastewater Quality for Irrigation in Orathanadu Block of Tamil Nadu, India

Aim: The current study focuses on the threats to the environment and human health that relate to using treated wastewater produced from the municipal sewage treatment plant of Orathanadu for irrigation purposes.
 Study Design: For this purpose, samples were taken monthly from the outflow wastewater and grouped into seasons.
 Place and Duration of study: Municipal sewage treatment plant located at Orathanadu, Tamil Nadu, during 2019.
 Methodology: The treated wastewater quality parameters such as pH, EC, total dissolved solids, total suspended solids, five days biological oxygen demand, chemical oxygen demand, and sodium adsorption ratio were measured monthly and grouped season-wise.
 Results: In treated wastewater, the minimal mean electrical conductivity values, total dissolved solids, five days biochemical oxygen demand, chemical oxygen demand, and sodium adsorption ratio were 0.81 dS m-1, 515.20 mg L-1, 25.50 mg L-1, 14.85 mg L-1, and 1.59, respectively. The suitability for irrigation based on the Sodium Adsorption Ratio (SAR) was calculated with standard equations and found experimentally as 1.59, 1.62, 1.59 and 1.56 during winter, summer, monsoon and post-monsoon seasons, respectively. To assess water suitability for irrigation, irrigation water classes are utilized for salinity hazard (EC) and sodium hazard (SAR), and samples were C3-S1 class in all four seasons. Furthermore, the data indicated a slight to moderate restriction on using this treated wastewater in irrigation due to chloride hazards.
 Conclusion: The results showed that treated wastewater meets national and international irrigation criteria and that treated wastewater can be used without restriction in light and medium-textured soils and in clay soils with leaching and drainage.