Treated Wastewater Research Articles

Aged Refuse Recycling to Treat Wastewater from Coffee Processing

Over the last two decades, the use of bioreactors filled with aged refuse extracted from closed areas of landfills has proven to be a viable alternative for the treatment of different types of wastewater. This study presents the results obtained during the evaluation of aged refuse used as filling material for a downflow bioreactor during the removal of the organic load present in wastewater generated in the wet processing of coffee. The tests were carried out over a period of 120 days, with 15 days to start up and stabilize the bioreactor and 105 days to perform treatability tests. The aged refuse, once extracted, was dried and sifted to a particle size of less than 50 mm. The bioreactor used had a cylindrical geometry (Ø = 0.20 m, and h = 3.40 m), and it was fed with hydraulic loads of 50, 100, and 150 L m−3 d−1. The analysis of the data obtained shows that the system studied achieves the removal of 98.3% of the initial organic load when fed with 150 L m−3 d−1. This showcases recycling aged refuse as a technically viable alternative to treat the wastewater generated during coffee processing. Also, the evaluated system has the advantage of needing a short period of time to achieve its stabilization, which turns out to be of great value, especially in its possible use in the treatment of residual water generated in the harvest of agricultural products where the period of harvest is very short.

Urban waste-water treatment plants as hotspots for birds : an environmental assessment highlights the role of a single dominant gull

Waste-water treatment plants (WWTPs) are still little explored in their ecological role. This work reports data obtained from standardized sampling for the two largest Italian WWTPs, to obtain seasonal patterns (late winter, spring, and autumn) of univariate diversity metrics in bird communities. The ecological conditions, linked above all to the high availability of water, with the presence of mud and trophic resources, and heterogeneous features (buildings, trees, and hedges), allow the presence of water-related and synanthropic bird species, using the site as a seasonal stopover and wintering sites. The large availability of biomass of invertebrates, linked to the sludge from the water-waste treatment plants, can provide an important trophic resource during spring migration. The richness, diversity and evenness did not differ significantly between the two plants analysed, both having comparable size and heterogeneity. The highest Simpson dominance values were recorded in autumn with species frequency concentrated in a few abundant species. Detrended Correspondence Analysis (DCA) shows a close association between the autumn period and the dominant Black-headed Gull (Chroicocephalus ridibundus), in both treatment plants, with possible implication on the spreading on zoonosis.

Temporal dynamic of soil microbial communities and antibiotic resistance markers exposed to increasing concentrations of sulfamethoxazole

The reuse of treated wastewater (TWW) for irrigation is widely applied to alleviate pressure on freshwater resources. However, TWW contains antibiotics that once in soils, can exert selective pressure, promoting the emergence and spread of antimicrobial resistance (AMR) in the environment. Current environmental risk assessments for antibiotic residues rely on indicators such as Predicted No Effect Concentrations (PNECs), usually determined in liquid media. These PNECs aim to predict antibiotic concentrations that may promote resistance in the environment. Given the complexity of soil matrices, few studies have established PNEC values for soil, which likely differ significantly from aquatic environments.To address this gap, we developed a simplified experimental model using soil microcosms irrigated with TWW and the antibiotic sulfamethoxazole (SMX) to estimate threshold concentrations favouring resistance transfer or/and emergence within the soil microbiome. We identified SMX concentrations between 0.01 and 0.1 mg/kgdry soil that likely increased the abundance of sulfonamide resistance genes in soil. A time window of 1 to 7 days post-exposure showed a temporary rise in sul1 and intl1 gene abundance (over 1 log/soil 16S rDNA), the appearance of SMX transformation products, and an increase in some Rhodocyclaceae. After 1.5 months of incubation and complete SMX transformation, the relative abundance of sul1 and intl1 remained about 0.5 log higher than in SMX-free controls and soils with SMX levels below 0.1 mg/kg dry soil. A persistent transformation product, 4-N-glucuronide-SMX, was also observed.Here, the estimated PNEC for SMX in soil, between 0.01 and 0.1 mg/kg, exceeds typical SMX concentrations found in soils exposed to TWW. This may suggest low impact on resistance selection for this compound in the context of TWW exposure. However further studies on other soils, water, and antibiotics need to be conducted to expand our knowledge on soil PNECs.

Influence of decades-long irrigation with secondary treated wastewater on soil microbial diversity, resistome dynamics, and antibiotrophy development

In arid and semi-arid regions, the use of treated wastewater (TWW) for irrigation is gaining ground to alleviate pressure on natural water sources. Despite said treatment, the existing methods fail to eliminate potentially dangerous contaminants. As such, this study assessed the impact of long-term TWW irrigation (5 and 25 years) on soil physicochemical properties and bacterial resistance to heavy metals (Pb, Cu, Cd) and antibiotics (tetracycline and amoxicillin). The results revealed heightened salinity and conductivity and reduced pH in irrigated soils. TWW induces harmful effects by reducing microbial density and size, leading to the disappearance of sensitive populations. Conversely, resilient populations, which mainly utilize antibiotics as a carbon source, have adapted. Metagenomic 16S amplicon sequencing analysis demonstrated a shift, notably reducing Actinobacteria, Bacteroidetes, and Firmicutes while increasing Acidobacteriota and Patescibacteria in treated soils. Operational Taxonomic Units affiliated with either Halomonadacea, or Saccharimonadacea and Vicinamibacteracea, were defined as indicators of the absence or presence of TWW contamination, respectively. We conclude that TWW irrigation significantly increases bacterial resistance to heavy metals, whereas the impact of antibiotics is nuanced, with antibiotrophy leveraging lower concentrations in treated soils.

Electrolysis for ammonia removal and hydrogen generation in urban wastewater: Innovative approaches to the water crisis

The global water crisis poses significant challenges, with millions lacking access to clean drinking water and increasing water scarcity affecting urban areas worldwide. This study explores the electrolysis of urban wastewater as a two-fold solution for ammonia (un-ionized NH3, and ionized NH4+) removal and hydrogen gas (H2) production. Traditional treatment methods often fail to remove ammonia efficiently, underscoring the need for innovative approaches. Electrolysis, known for its versatility, energy efficiency, and environmental friendliness, emerges as a promising solution in wastewater treatment applications. This research utilized a dimensionally stable electrode (DSA) comprising a Ru-Ir anode and a stainless-steel cathode to electrochemically oxidize ammonia and produce H2. The study investigates the effects of current density, J (83.33–416.6 A/m2) on the treatability of urban wastewater. Maximum H2 production was achieved at J of 416.6 A/cm2 after 300 min reaction time. Under optimal conditions (333.3 A/m2, 0.5 mm inter-electrode distance, and 300 min of operation), the process achieved removal efficiencies of 98.94 % for ammonia, 78.18 % for total suspended solids (TSS), 50.73 % for chemical oxygen demand (COD), and complete removal (∼100 %) of total coliforms. Gas chromatography (GC) assessed the composition of gases of interest generated during electrolysis. This approach addresses environmental pollution and freshwater scarcity and generates an energy resource, presenting a scalable solution for cities worldwide facing similar challenges.

Tapping into haloalkaliphilic bacteria for sustainable agriculture in treated wastewater: insights into genomic fitness and environmental adaptation.

The increasing salinity and alkalinity of soils pose a global challenge, particularly in arid regions such as Tunisia, where about 50% of lands are sensitive to soil salinization. Anthropogenic activities, including the use of treated wastewater (TWW) for irrigation, exacerbate these issues. Haloalkaliphilic bacteria, adapted to TWW conditions and exhibiting plant-growth promotion (PGP) and biocontrol traits, could offer solutions. In this study, 24 haloalkaliphilic bacterial strains were isolated from rhizosphere sample of olive tree irrigated with TWW for more than 20years. The bacterial identification using 16S rRNA gene sequencing showed that the haloalkaliphilic isolates, capable of thriving in high salinity and alkaline pH, were primarily affiliated to Bacillota (Oceanobacillus and Staphylococcus). Notably, these strains exhibited biofertilization and enzyme production under both normal and saline conditions. Traits such as phosphate solubilization, and the production of exopolysaccharide, siderophore, ammonia, and hydrogen cyanide were observed. The strains also demonstrated enzymatic activities, including protease, amylase, and esterase. Four selected haloalkaliphilic PGPR strains displayed antifungal activity against Alternaria terricola, with three showing tolerances to heavy metals and pesticides. The strain Oceanobacillus picturea M4W.A2 was selected for genome sequencing. Phylogenomic analyses indicated that the extreme environmental conditions probably influenced the development of specific adaptations in M4W.A2 strain, differentiating it from other Oceanobacillus picturae strains. The presence of the key genes associated with plant growth promotion, osmotic and oxidative stress tolerance, antibiotic and heavy metals resistance hinted the functional capabilities might help the strain M4W.A2 to thrive in TWW-irrigated soils. By demonstrating this connection, we aim to improve our understanding of genomic fitness to stressed environments. Moreover, the identification of gene duplication and horizontal gene transfer events through mobile genetic elements allow the comprehension of these adaptation dynamics. This study reveals that haloalkaliphilc bacteria from TWW-irrigated rhizosphere exhibit plant-growth promotion and biocontrol traits, with genomic adaptations enabling their survival in high salinity and alkaline conditions, offering potential solutions for soil salinization issues.

Production of Bio-Diesel from Dairy Waste Scum

Abstract-Dairy factory waste scums are increasingly being considered a valuable resource. However, these wastes may also contain contaminants, natural or artificial, that may adversely affect the land or water to which they are discharged. The study investigates the potential of using dairy waste scum as a feed stock for bio-diesel production. Present study optimized the parameters involved in the alkali catalysed Trans esterification process of dairy waste scum oil. The effects of methanol to oil ratio, temperature and amount of KOH were investigated. A study was conducted to evaluate the capability of production of biodiesel from consortium of native microalgae culture in dairy farm treated waste water. Native algal strains were isolated from dairy farm waste waters collection tank (untreated wastewater) as well as from holding tank (treated wastewater). The consortium members were selected on the basis of fluorescence response after treating with Nile red reagent. Preliminary studies of two commercial and consortium often native strains of algae showed good growth in waste waters. A consortium of native strains was found capable to remove more than 98% nutrients from treated waste water. The biomass production and lipid content of consortium cultivated in treated waste water were 153.54t ha-1 year-1 and 16.89%, respectively. 72.70% of algal lipid obtained from consortium could be converted into biodiesel. The present study found that bio- diesel from dairy waste scum is quite suitable as an alternative to petroleum diesel with recommended fuel properties as per ASTM standards. By using dairy waste scum as a feed stock for bio diesel and the environmental impact related to the disposal of dairy scum Keywords: Environment,Bio-Diesel,Dairy Waste Scum, Extraction of Lipids

Assessing the presence of microplastic in agriculture soils irrigated with treated waste waters using Lumbricus sp.: Ecotoxicological effects

Global water scarcity entailed the use of treated wastewater (TWW) in agriculture, however, this water can vehiculate numerous pollutants into soil and further crops such as microplastics (MPs). To date, few studies had quantified the accumulation of MPs in soils and earthworms after irrigation with TWW as well as their toxicological effects. Hence, the main objective of the present work is to evaluate the toxicity of MPs using Lumbricus sp. earthworms collected from TWW irrigated soils with an increasing gradient of time (5 years, 16 years and 24 years). MPs determination in soil, as well as in earthworms were performed. The intestinal mucus was quantified, and cytotoxicity (Lysosomal membrane stability (LMS), Catalase (CAT) and glutathione-S-Transferase (GST) activities), neurotoxicity (Acetylcholinesterase activity (AChE)) and genotoxicity (Micronuclei frequency (MNi)) biomarker were assessed. Our results revealed that the use of TWW rendered MPs accumulation in earthworms' tissues and induce alteration on the intestinal mucus. An important cytotoxicity time-depending was observed being associated with an increase on genotoxicity. Overall, the present investigation highlights the ecotoxicological risk associated with the use of TWWs as an important driver of MPs and consequently measures are necessary to reduce MPs in wastewater treatment plans to improve this non-conventional water quality.

Microwave Radiation in Wastewater Treatment and Sedimentations Treatment Technologies

The main results of research on the use of microwave radiation in wastewater treatment and treatment of their sedimentations, as well as water treatment waste, are presented. The thermal influence of microwaves on the water and sedimentations properties is considered. The experimental data obtained by foreign and domestic specialists for the following processes using microwaves are shown: degradation of organic substances, de-emulsification of oil-containing wastewater, removal of metals, disinfection, intensification of biogas yield, sediments pyrolysis, modification of the absorbents, intensification of compaction and dewatering of natural water treatment sedimentation. New microwave equipment for treatment the various wastes is described.

One Health Threat of Treated Wastewater Discharge in Urban Ohio Rivers: Implications for Surface Water and Fish Gut Microbiome and Resistome.

Wastewater treatment plants (WWTPs) are thought to be a major disseminating source of antibiotic resistance (AR) to the environment, establishing a crucial connection between human and environmental resistome. The objectives of this study were to determine how wastewater effluents impact microbiome and resistome of freshwater and fish, and identify potential AR-carrying clinically relevant pathogens in these matrices. We analyzed wastewater influent and effluent from four WWTPs in three metropolitan areas of Ohio, USA via shotgun metagenomic sequencing. We also sequenced river water and fish guts from three reaches (upstream, at the WWTP outfall, and downstream). Notably, we observed a decline in microbiome diversity and AR gene abundance from wastewater to the receiving river. We also found significant differences by reach and trophic level (diet) in beta-diversity of the fish gut microbiomes. SourceTracker revealed that 0.443 and 0.248 more of the of the fish gut microbiome was sourced from wastewater effluent in fish from the outfall and downstream locations, respectively, compared to upstream fish. Additionally, AR bacteria of public health concern were annotated in effluent and river water samples, indicating potential concern for human exposure. In summary, our findings show the continued role of wastewater as a significant AR reservoir and underscores the considerable impact of wastewater discharge on aquatic wildlife, which highlights the One Health nature of this issue.

Deciding on the priority of process parameters using the analytical hierarchy process in electrochemical wastewater treatment and investigation of paint wastewater treatability

In planning electrochemical treatment processes, it is thought that decision-making tools should be used in the selection of the main parameters that are likely to affect pollutant removal. According to detailed research in the literature, no previous study has systematically prioritized process parameters in electrochemical wastewater treatment using the analytical hierarchy process (AHP). In this study, published articles in the literature on the subject were used to determine which parameters were used in the treatment processes and with what frequency. Using the obtained results, the priorities of the process parameters were estimated with the help of AHP within the scope of the removal efficiencies and treatment cost criteria. According to the AHP analysis results, it was determined that the most effective parameters for both electrocoagulation and electrooxidation processes were pH (0.241), current density (0.171), voltage (0.171), conductivity (0.107), concentration (0.105) and reaction time (0.094). Four of the independent parameters were selected and treatability studies were carried out using both electrocoagulation (with Al electrode pair and Fe electrode pair) and electro oxidation (with Graphite electrode pair and Ti electrode pair) methods for different levels of each parameter. The pH, current density, voltage, and reaction time were chosen as independent parameters based on decision making process. Unit costs for removal of chemical oxygen demand with Al, Fe, graphite, and Ti electrodes were obtained as 1.05, 2.56, 0.074, and 14 USD per m3 wastewater, respectively. Unit costs for removal of color with Al, Fe, graphite, and Ti electrodes were obtained as 0.68, 1.20, 0.074, and 14 USD per m3 of wastewater, respectively. In addition, nine batch kinetic studies were conducted for optimum conditions obtained from pre-treatment studies with Al and Fe electrodes. Removal of chemical oxygen demand was achieved at 64 % with aluminum and iron electrodes at 40 and 70 min, respectively. The results obtained from kinetic studies showed that adsorption of organic substances fit the 2nd-order kinetic model and the correlation coefficient was 0.95 and 0.96 for aluminum and iron electrodes, respectively.

Sanitary Problems and Trace Metals Bioaccumulation during Drip Irrigation with Treated Wastewater in Okra

Water scarcity, mainly in arid and semi-arid zones, has encouraged efforts to adopt non-conventional waters for food production and agricultural development. Treated Wastewater (TWW) is one of the most continuously produced, accessible, and inexpensive water resources, with great potential for use in irrigation. The aim of this study was to investigate the combined effect of drip irrigation methods (surface vs. subsurface at 15 cm depth) and water quality (borehole water vs. treated wastewater) on soil water content, morphological and physiological traits, and nutrient content in the plant and fruit of okra grown in the Nabeul region of north-west Tunisia, a semi-arid zone. The results indicated that Okra yield was significantly affected by water quality rather than irrigation technique. Irrigation with TWW significantly increased the Okra plant height; leaf number; total fruit/m²; final yield and leaf area compared with borehole water. Nutrient levels (Fe, Cu, Zn, and Mn) in Okra plant parts (root, stem, leaf, and fruit) were also significantly increased with TWW in subsurface drip irrigation. Apart from these increased parameters were related to better soil moisture and increased available nutrients in the root zone. In terms of bioaccumulation, apart from Ni, the elements analyzed (Zn, Mn, Cu, Pb, Co, Cd) in plant and fruits showed higher values in treated wastewater than in borehole water with fruit values exceeding the toxicity threshold for Cd and Pb. Furthermore, the increase in the content of trace metal elements analyzed in the fruit following irrigation with TWW did not affect the human Health Risk Index (HRI), which remained below 1 for all treatments. Furthermore, with regard to bacterial and fungal contamination of fruit, we note that although these parameters are significantly higher in Irrigation with TWW, they remain below the toxicity thresholds. Thus, the long-term effect and continuous monitoring of the water and fruit quality in wastewater-irrigated areas to take remedial actions for sustainable agriculture development and protect ecosystems are recommended.

Life Cycle Assessment of Green Space Irrigation Using Treated Wastewater: A Case Study

Water scarcity is a pressing issue that makes it essential to manage this resource efficiently and sustainably. One solution to combat this issue is the use of treated wastewater (TWW) to irrigate green spaces in cities. However, it is crucial to evaluate the environmental impacts associated with this practice. To this end, life cycle assessment (LCA) is the most advanced tool available. The objective of this study was to assess the environmental implications of using TWW for lawn irrigation in the city of Viseu. The ReCiPe 2016 method, supported by SimaPro software, was employed for life cycle impact assessment (LCIA). An attributional approach was used, and the system boundaries were expanded to include the non-discharge of TWW into the receiving environment, the avoided consumption of domestic water, and the avoided consumption of chemical fertilizers. The results revealed that using TWW for lawn irrigation is preferable in terms of human health and ecosystem damage but unfavorable in terms of resource damage. When considering the impact of water consumption on human health and terrestrial and aquatic ecosystems, it is recommended to use treated wastewater for lawn irrigation.

Comparative High-Throughput Sequencing Analysis of the Bacterial Community Associated with the Rhizosphere of Date Palm (Phoenix dactyllifera L.) Irrigated with Treated Wastewater and Groundwater

Water scarcity is a major agricultural issue in most arid and semi-arid regions of the world. Alternative water supplies, such as the reuse of wastewater for agricultural irrigation, have been introduced. However, little is known about their impact on the soil and rhizosphere microbiomes that receive irrigation. Therefore, this work evaluates the impact of treated wastewater (TWW) irrigation on the soil and rhizosphere bacterial communities of date palms in Al Madinah, Saudi Arabia. In this study, metagenomic DNA from the rhizosphere of the date palm was sequenced using Illumina high-throughput sequencing. According to the observed OTUs, Chao1 richness estimations, and Shannon diversity values, soils from groundwater-irrigated date palms showed higher microbial diversity than did soils from TWW-irrigated date palms. A total of 569 OTUs were generated; most of them (97.3%) were assigned into 15 different phyla, whereas 2.7% were marked as unclassified. DNA sequence analysis of the WWT-irrigated rhizosphere showed that the most abundant phyla were Firmicutes (43.6%), Bacteroidetes (17.3%), Proteobacteria (15.2%), and Actinobacteria (14.6%), representing more than 90.7% of the total community, while the soil of the rhizosphere irrigated with GW was dominated by Actinobacteria (44.1%), Proteobacteria (23.4%), Firmicutes (15.5%), and Gemmatimonadetes (4.9%). The most frequently observed species in the two soils were also different. The dominant species in TWW-irrigated soil was Planococcus plakortidis, which is prevalent in saline and moderately saline habitats and can play an important ecological role. The GW-irrigated rhizosphere exhibited higher levels of biocontrol bacteria, particularly Nocardioides mesophilus. These results provide a comprehensive understanding and insights into the population dynamics and microbiome of date palm rhizosphere. The findings show that the irrigation water quality has a significant impact on the microbiome composition. Identifying the microbial diversity is the first step toward determining the best way to use TWW in irrigation.

Integrated environmental management and GPS-X modelling for current and future sustainable wastewater treatment: A case study from the Middle East

In the context of today's rapidly changing environmental challenges, accurately predicting the performance and efficiency of environmental management strategies is crucial. Particularly in the Middle East, where research on wastewater treatment plants (WWTPs) is notably lacking, addressing this need is imperative. This study investigates the treatment efficiency of a wastewater treatment plant and proposes various techniques to enhance its performance. Employing a case study method, we utilise the GPS-X model to forecast the plant's performance under diverse scenarios, offering solutions for future challenges. The results reveal that the current plant layout operates efficiently, with removal efficiencies for Total Suspended Solids (TSS), Chemical Oxygen Demand (COD), and Biochemical Oxygen Demand (BOD) at 98.3 %, 95.1 %, and 96.1 %, respectively. The outlet Dissolved Oxygen (DO) of 1.9 mg/L meets local wastewater reuse standards. Furthermore, the GPS-X model forecasts the plant's performance under different scenarios, suggesting the feasibility of a new layout within 20–25 years and the need for additional units after 40 years. As inflow approaches maximum design capacity, simulation results underscore the importance of utilising the full plant design and expanding it for optimal operation over 60 years. This research provides critical insights for improving WWTP performance and emphasizes the significance of strategic planning in addressing long-term environmental management challenges. Moreover, this study represents a pioneering effort in addressing critical water scarcity challenges in Jordan by exploring the potential of treated wastewater (TWW) as a sustainable solution, thus contributing to the advancement of environmental management practices in the region.

Cost-benefit analysis of an irrigation unit with treated wastewater in Chihuahua, Mexico

The reuse of water in agriculture is an alternative to guarantee food security in Mexico and efficient management of this resource. The objective was to conduct an economic evaluation by benefit-cost analysis in an irrigation district of treated wastewater (TWW) in Tabalaopa-Aldama, Chihuahua, Mexico. The cost-benefit methodology was used to estimate the economic assessment of public projects. The results indicated that the project operation would obtain a net social value of $1,054.4 million, a social return intern fee of 31.19 %, and a cost-benefit relation of 2.48. Even if the costs and benefits increase by up to 30 %, the project would still be economically viable and provide social benefits. The start-up of a TWW irrigation district will generate economic benefits for society and promote the reduction of environmental impact on the agricultural land in Tabalaopa, Aldama, Chihuahua, Mexico.

Long-term resilience in wastewater management: Optimizing treated wastewater allocation with a dynamic multi-agent approach

Water scarcity poses a significant challenge to sustainable development, necessitating innovative approaches to manage limited resources efficiently. Effective water resource management involves not just the conservation and distribution of freshwater supplies but also the strategic reuse of treated wastewater (TWW). This study proposes a novel approach for the optimal allocation of treated wastewater among three key sectors (user agents): agriculture, industry, and urban green space. Recognizing the intricate interplays among these sectors, System Dynamics (SD) and Agent-Based Modeling (ABM) were integrated in a Complex Adaptive System (CAS) to capture the interactions and feedback mechanisms inherent within treated wastewater allocation systems. The Non-dominated Sorting Genetic Algorithm II (NSGA-II) serves as the optimization tool, enabling the identification of optimal allocation strategies across various management scenarios over a 25-year simulation period. Our research navigates the complexities of long-term resource management, accounting for each sector's evolving its objectives and guidelines along the whole system objectives and strategies. The outcomes demonstrate how treated wastewater can be effectively distributed to support economic and social equity –as the system objectives-while supporting agricultural and industrial growth and enhancing efficiency and social well-being –reflecting individual agent objectives-within the CAS framework. The research explores four distinct management scenarios, each prioritizing different sectors to address water resource management challenges. Notably, all four scenarios align with the strategies required by the ruler (government), providing strategic guidance to water resource managers for decision-making. The simulation results reveal a scenario where all sectors' demands are met, with Scenario 4 emerging as the most effective. Scenario 4 aligned with the objectives and guidelines of each sector, demonstrating significant improvements in the CY (Agriculture agent index; increased from 0.2 to 0.68), IGI (Industry agent index; increased from 1 to 1.63), and GAI (Urban Green Space agent index; increased from 1 to 1.23) indices over the 25-year simulation period. By providing a strategic blueprint for policymakers and stakeholders, this study contributes significantly to the discourse on sustainable water resource management, presenting a replicable model for similar contexts globally, where judicious allocation of treated wastewater is paramount for achieving harmony between human activity and ecological preservation.

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.

New strategy based on Hammerstein–Wiener and supervised machine learning for identification of treated wastewater salinization in Al-Hassa region, Saudi Arabia

The agricultural sector faces challenges in managing water resources efficiently, particularly in arid regions dealing with water scarcity. To overcome water stress, treated wastewater (TWW) is increasingly utilized for irrigation purpose to conserve available freshwater resources. There are several critical aspects affecting the suitability of TWW for irrigation including salinity which can have detrimental effects on crop yield and soil health. Therefore, this study aimed to develop a novel approach for TWW salinity prediction using artificial intelligent (AI) ensembled machine learning approach. In this regard, several water quality parameters of the TWW samples were collected through field investigation from the irrigation zones in Al-Hassa, Saudi Arabia, which were later assessed in the lab. The assessment involved measuring Temperature (T), pH, Oxidation Reduction Potential (ORP), Electrical Conductivity (EC), Total Dissolved Solids (TDS), and Salinity, through an Internet of Things (IoT) based system integrated with a real-time monitoring and a multiprobe device. Based on the descriptive statistics of the data and correlation obtained through the Pearson matrix, the models were formed for predicting salinity by using the Hammerstein-Wiener Model (HWM) and Support Vector Regression (SVR). The models’ performance was evaluated using several statistical indices including correlation coefficient (R), coefficient of determination (R2), mean square error (MSE), and root mean square error (RMSE). The results revealed that the HWM-M3 model with its superior predictive capabilities achieved the best performance, with R2 values of 82% and 77% in both training and testing stages. This study demonstrates the effectiveness of AI-ensembled machine learning approach for accurate TWW salinity prediction, promoting the safe and efficient utilization of TWW for irrigation in water-stressed regions. The findings contribute to a growing body of research exploring AI applications for sustainable water management.

A Descriptive Study on Performance Evaluation of Sewage Treatment System

Abstract: As The rapid expansion of modern housing and industrialization around the cities has polluted environment. This trend was observed in many developed countries in the beginning of nineteenth century which resulted in the contamination of air, water, soil etc. with pollutants. If the pollutants are released in the environment and left untreated they would cause serious diseases in both humans and animals. Large scale pollution of water bodies around the globe became a major problem due to release of industrial and domestic waste directly in water streams. To prevent the leaching of pollutants in the ground water scientist developed various methods of wastewater treatment based on the hazardous chemicals and microorganisms, which were present in the untreated water. Modern sewage treatment plants were installed in big cities to treat the water released from households. Most STPs were designed based on the stringent criteria to check the pollutants levels in the treated water so that when it is released or recycled it is safe to the environment. Modern day STP plants have a high cost of operation due to huge power consumption. In order to reduce the pollutant levels in the wastewater this study was conducted using a Eco Bio Block (EBB) techniques with aeration and without aeration. A comparison of EBB was also carried out with MBBR technique. Our results show that when EBB technique was applied with aeration it is effective in reducing pollutant levels in the wastewater akin to MBBR. In addition, we tested the EBB without aeration and found that the treated waste water has relatively low levels of BOD, COD and turbidity, suggesting that the treated water can be utilized for landscaping and horticulture activities. Overall, the outcomes from this study are encouraging to adopt EBB in smaller towns and in small housing societies to treat the wastewater prior to release. The paper focuses on reviewing the various sewage treatment methods and their results.