Wastewater Reclamation Research Articles

A Low Cost Wastewater Reclamation Unit comprising a Lamella Settler for reducing Fresh Water Usage in Carwash Stations

A Low Cost Wastewater Reclamation Unit comprising a Lamella Settler for reducing Fresh Water Usage in Carwash Stations

Effect of Wastewater Irrigation on Yield, Water Productivity and Economics of Sunflower and Toria Crop

Water scarcity is one of the most important issue affecting the global economy and human livelihoods. Climate change, rapid population growth, freshwater pollution and depletion are among the factors exacerbating the situation. Although not yet fully exploited, wastewater reclamation and reuse are considered potential mechanisms to mitigate the challenge. To evaluate the impact of wastewater on yield, economics, soil nutrient status, seed oil content and water productivity, a two-year experiment at farmers field in Angul, Odisha was taken up. The sunflower yield was found significantly higher with wastewater irrigation (10%) which was mainly contributed by higher head diameter (15.3 cm), no. of achenes per head (467) and 100 achene weight (69g). Similarly, toria crop irrigated with wastewater had higher yield by 11% resulting from higher siliquae per plant (179), no of seeds per siliqua (12.1) and test weight (4.6) compared to freshwater irrigation. Besides this soil nutrients and oil content was higher in wastewater irrigated toria and sunflower crop than freshwater crops. Benefit cost ratio was higher in wastewater irrigated sunflower (3.9) and toria (2.0) crop compared to freshwater irrigated crops (3.0 and 1.4 respectively for sunflower and toria). Water productivity under wastewater irrigation in sunflower (0.38 kg/m3) and toria (0.21 kg/m3) was higher than freshwater irrigated crops by 10-12%. The findings of the present study suggest that wastewater can be used as a source of irrigation for oilseed crop in Angul Odisha where water scarcity is acute during rabi season.

Facile fabrication of superhydrophobic carbon-doped nanofibrous mat for solar-driven desalination

Recently, solar-driven localized heating interfacial evaporation for desalination has attracted much attention to draw freshwater from sewage or seawater. However, salt scaling resulted from concentration polarization, as well as the subsequently deterioration of evaporation rate and energy efficiency, are the major obstacles for the application of solar desalination. In this work, carbon-doped nanofibrous mat with photothermal and superhydrophobic properties were facilely fabricated via incorporation of activated carbon (AC) nanoparticles and hydrophobic modification with polydimethylsiloxane (PDMS). The obtained nanofibrous mat exhibited outstanding light absorption (> 93.0%), superhydrophobic characteristics (> 155°) and high porosity (> 82%). Solar-driven evaporation experiments demonstrated that evaporation rate of the nanofibrous mat reached up to 1.2kg·m-2·h-1 with energy efficiency of 82.1%. Moreover, crystal nucleation and growth on the superhydrophobic carbon-doped mat were dramatically suppressed, whose lifespan was prolonged from 4h to as long as 19h with near-saturated NaCl solution as the feedwater. Therefore, the fabricated superhydrophobic carbon-doped nanofibrous mat might find its applications in stable solar-driven evaporation for seawater desalination or wastewater reclamation.

Ozone-Resistant Bacteria, an Inconvenient Hazard in Water Reclamation: Resistance Mechanism, Propagating Capacity, and Potential Risks.

Resistant bacteria have always been of research interest worldwide. In the urban water system, the increased disinfectant usage gives more chances for undesirable disinfection-resistant bacteria. As the strongest oxidative disinfectant in large-scale water treatment, ozone might select ozone-resistant bacteria (ORB), which, however, have rarely been reported and are inexplicit for their resistant mechanisms and physiological characteristics. In this study, six strains of ORB were screened from a water reclamation plant in Beijing. Three of them (O7, CR19, and O4) were more resistant to ozone than all previously reported ORB or even spores. The ozone consumption capacity of extracellular polymeric substances and cell walls was proved to be the main sources of bacterial ozone resistance, rather than intracellular antioxidant enzymes. The transcriptome results elucidated that strong ORB possessed a combined antioxidant mechanism consisting of the enhanced transcription of protein synthesis, protein export, and polysaccharide export genes (LptF, LptB, NodJ, LivK, LviG, MetQ, MetN, and GltU). This study confirmed the existence of ORB in urban water systems and brought doubts to the idea of a traditional control strategy against chlorine-resistant bacteria. A salient "trade-off" effect between the ozone resistance and propagation ability indicated the weakness and potential control approaches of ORB.

Wastewater reclamation for the production of construction bricks: technical, economic, and environmental feasibility

ABSTRACT This study evaluates the technical, economic, and environmental impacts of using treated wastewater as a substitute for potable water (PW) in mortar bricks production. The study experimentally compared the reuse of raw sewage, UASB reactor effluent, activated sludge effluent, and filtered effluent to produce mortar bricks which were tested for mixture workability and compressive strength over curing periods of 3, 7, and 28 days. Slump values of the mixtures were close to 110 mm for all samples, and 28-day compressive strengths varied between 31.2 and 34.8 MPa, higher than the 17.2 MPa required for Type M mortars. Mortar made with activated sludge and filtered effluent exhibited properties comparable to those made with PW. Economic analysis revealed a slight cost increase of 1.7% due to effluent disinfection, but significant environmental benefits, such as reduced eutrophication due to the wastewater reclamation and water conservation, were noted, primarily due to the avoidance of discharging treated effluent into surface water bodies. These findings underscore the feasibility of using treated wastewater in construction, highlighting its potential to enhance sustainability in this field, and suggesting the necessity for further studies on the long-term effect of using reclaimed wastewater cementitious products.

Coupling UVC254 nm-LED/H2O2 and Fenton processes for disinfection and contaminants of emerging concern removal in continuous mode for wastewater reclamation in accordance with EU 2020/741

A novel strategy based on the sequential combination of UVC254 nm-LED/H2O2 and the Fenton process at neutral pH in continuous flow mode for wastewater reclamation has been assessed. The concentration of Escherichia coli (E. coli) reached water class A according to the European Union (EU) Regulation 2020/741 (≤10 CFU/100 mL) and a 87 ± 2 % of the contaminants of emerging concern (CECs) load was removed, complying with the new proposal regarding Urban Wastewater Treatment (Directive COM (2022) 541). To reach these results, initially the municipal wastewater secondary effluent was kept under UVC254 nm-LED/H2O2 process with a hydraulic residence time (HRT) of 5 min, a liquid depth of 5-cm and 1.8 mmol L−1 of H2O2. In the sequence, addition of Fe2+ to the outside of the UVC254 nm-LED reactor was added to acquire the desired concentration of 1.8 mmol L−1 Fe2+ (Fenton process). To obtain the same disinfection and CECs degradation by only UVC254 nm-LED/H2O2 process, 45 min-HRT were necessary. These results show that the coupled processes are the best strategy, given the reduction in HRT (from 45 to 5 min) and total cost (from 1.79 to 0.54 € m−3). In addition, new research on the application at pilot scale will encourage to evaluate the long-term toxicity of the reclaimed wastewater and to identify the main transformation products of the most abundant CECs.

Bio-refinery of organic pollutants for wastewater reclamation

With rapid development of global climate change and resource scarcity, the demand for sustainable wastewater reclamation technologies is growing rapidly. Alginate like exopolymers (ALE) are value-added biopolymers that can be recovered from excess biomass. In this study, a novel biopolymer value-driven moving bed biofilm reactor (bMBBR) was constructed to achieve high-efficiency conversion of organics to Alginate like exopolymers (ALE). The results revealed that excellent COD and low NH4+-N reduction could be achieved, with the reduction efficiencies of 87.7 ± 0.6 % and 12.6 ± 0.8 %, respectively. It is indicated that high-rate organics conversion and blockage of nitrification activity for energy saving could be simultaneous achieved in this process. Additionally, the superior settleability (SVI30 < 80 mL/g) and functional genera related to extracellular polymeric substances (EPS) secretion were observed, making it promising for ALE recovery from residual biomass. The yields of ALE extraction from biofilm and suspended biomass ranged of 232.9–381.5 mg/g VSS. The property analyses demonstrated that the biopolymer had a similarity functional group between two samples and commercial alginate. Meanwhile, the profit evaluation results suggested that the net profit could be reached of 0.54 CNY/kg SS in the present study, which was higher than that of conventional waste activated sludge (−1.92 CNY/kg SS). Moreover, the economic value of ALE (0.38 CNY/m3 wastewater treated) was also 2.93 times of that obtained from CH4 (0.13 CNY/m3 wastewater treated). In general, the present study provides a prove of concept that bio-refinery of organics into value-added biopolymers could offer a promising direction towards next generation of sustainable wastewater treatment plants.

Evaluating the behavior and environmental risks of carbamazepine and its metabolites in soil aquifer treatment: Insights from deconjugation dynamics and toxicity assessment

The presence of pharmaceuticals in the environment has been a growing concern. Recent studies highlight the ecological risks of pharmaceuticals, but most risk assessments focus on the parent drug, neglecting metabolites. This study examines the behavior and environmental risks of carbamazepine (CBZ) and its metabolites in soil aquifer treatment (SAT) for wastewater reclamation. Findings indicate that CBZ metabolites' total concentration exceeds that of CBZ. Notably, carbamazepine-N-glucuronide (CBZ-N-Glu) concentration decreased from 48.12 ng/L to undetectable levels during SAT, while CBZ concentration increased from 64.87 to 95 ng/L, suggesting possible deconjugation of CBZ-N-Glu. Batch and column experiments confirmed the hypothesis, showing a gradual disappearance of CBZ-Glu and a corresponding rise in CBZ concentration when CBZ-N-Glu was spiked into a recirculated SAT system. Quantitative structure-activity relationships (QSAR) analysis revealed that CBZ exhibits higher acute and chronic toxicity, with metabolites showing varying levels of developmental toxicity. The study also evaluates the persistence, mobility, and toxicity (PMT) characteristics of CBZ and its metabolites, highlighting CBZ-N-Glu's particularly adverse PMT characteristics compared to CBZ. In summary, the residual pharmaceuticals in the reclaimed water process should be evaluated systematically, considering both the parent compounds and their metabolites.

Impact of PCLNPG Nanopolymeric Additive on the Surface and Structural Properties of PPSU Ultrafiltration Membranes for Enhanced Protein Rejection

This research explored the use of a partially cross-linked graft copolymer (PCLNPG) as an innovative nanopolymer pore-forming agent to enhance polyphenylsulfone (PPSU) membranes for protein separation applications. The study systematically examined the impact of incorporating PCLNPG at varying concentrations on the morphological and surface properties of PPSU membranes. A thorough characterization of the resulting PPSU-PCLNPG membranes was performed, focusing on changes in morphology, water affinity, porosity, pore size, and pore size distribution. The experimental findings demonstrated that the use of PCLNPG led to a significantly more porous structure, as confirmed by SEM analysis, with notable increases in porosity and pore size (nearly double). Additionally, the hydrophilicity of the PPSU membrane was remarkably enhanced. Performance evaluations revealed a substantial improvement in pure water flux, with the flux nearly tripling. The BSA retention was directly correlated with the concentration of the PCLNPG pore former for a loading range of 0.25–0.75 wt.%. The incorporation of PCLNPG also reduced the membrane fouling propensity by reducing both cake layer resistance (Rc) and pore plugging resistance (Rp). These results underscore the potential of PCLNPG-PPSU membranes for wastewater reclamation and nutrient recovery applications.

Impact of N loading on Microbial Community Structure and Nitrogen Removal of an Activated Sludge Process with Long SRT for municipal wastewater treatment

Biological nutrient removal process is pivotal in controlling nitrogen and phosphorus from municipal wastewater treatment and reclamation plants in the water environment. The efficiency of municipal wastewater treatment is affected by the fluctuation of influent quality. In this study, the impact of N loading on the removal efficiency and the microbial community structure of activated sludge with long sludge retention time were investigated. The results showed that the effluent NH4+-N and NO2--N concentration were lower than 0.5 mg/L, and the TN removal efficiencies were 79.77% and 65.80%, respectively. The dehydrogenase activity, specific oxygen uptake rate, specific nitrification rate, and specific denitrification rate increased as the N loading increasing. At the phylum level, the most dominant bacterial was affiliated with Proteobacteria in the two systems, accounting for 60.65% and 48.62%, respectively. At the genus level, Acinetobacter, Thauera, and Zoogloea played significant roles in denitrification. The ammonia oxidation bacteria and nitrite-oxidizing bacteria were of the genus Nitrosomonas (r-strategist) and Nitrospira (K-strategist).

Stabilized oily-wastewater separation based on superhydrophilic and underwater superoleophobic ceramic membranes: Integrated experimental design and standalone machine learning algorithms

BackgroundReliable computational approaches to evaluate ceramic membrane performance in wastewater treatment mark a transformative step towards optimizing separation processes, ensuring environmental sustainability, and advancing water purification technologies. The current study explores the influential factors using artificial intelligence (AI) tools in the performance evaluation of superhydrophilic and underwater super-oleophobic ceramic membranes for the selective treatment of oily wastewater. MethodsThe chemometrics scenario of the research based on established experimental work employs advanced AI models viz: Random Forest (RF), Support Vector Regression (SVR), and Gaussian Process Regression (GPR) to predict the efficacy of these membranes in terms of rejection and flux. The model predictions were evaluated using the Pearson Correlation Coefficient (PCC), Willmott Index (WI), mean absolute percentage error (MAPE), and mean absolute error (MAE). Significant findingsFrom the results, GPR had shown good agreement with correlations (WI=99.9) during the training and testing phases for flux prediction, indicating an exceptional model fit with negligible error (MAPE=0.001, MAE=0.000 in the testing phase). For rejection modelling, GPR and SVR exhibit similar levels of accuracy, with moderate PCC and WI values, while RF reveals significant limitations with the lowest scores across all statistical metrics. The findings highlight the potential of AI in optimizing wastewater treatment processes, with GPR identified as the most promising model for flux prediction. This study would provide insight into the modelling of the membrane separation process for oily wastewater and integrate AI in the performance evaluation of wastewater reclamation.

Upcycling of waste acrylonitrile butadiene styrene as N-doped carbocatalyst for peroxymonosulfate-induced degradation by solvothermal process

Advanced upcycling of post-consumer waste plastics into functional carbocatalyst has emerged rapidly as a strategy for simultaneously achieving waste plastics disposal and alternative catalysts fabrication. In this study, this type of magnetic N-doped carbocatalyst hybrid was fabricated by a facile solvothermal impregnation of metallic nitrates into waste acrylonitrile butadiene styrene polymer. The key point of the process was that solvothermal impregnation remarkably enhanced a homogeneous metal dispersion and graphitic N structure was stably introduced into carbocatalyst due to N heteroatoms in inherent structure of waste plastics. It was found that carbocatalyst with predominant encapsulation of magnetic CoFe2O4, Fe0.64Ni0.36 and CoFe possessed excellent catalytic performance to activate peroxymonosulfate with substantial degradation of 98.3% synthetic azo contaminant. Mechanism study indicated that graphitic N and metal species exhibited strong synergistic effects for peroxymonosulfate activation to generate SO4·−, ·OH and 1O2. This system achieves a dual-pathway degradation and electron transfer from azo contaminant to peroxymonosulfate to dominate degradation of azo contaminant, providing a new insight into magnetic carbocatalyst confinement from plastic scrap for peroxymonosulfate activation and its versatile application in wastewater reclamation.

The green resource recovery process of a new type of selective bipolar membrane electrodialysis system for saline wastewater treatment

The selective electrodialysis with bipolar membrane (BMSED) is an advanced electro-membrane process that combines monovalent perm-selective ion exchange membrane and a bipolar membrane, and presented significant potential in high salinity wastewater treatment and reclamation. Herein, we accomplished an in-depth assessment of the external-integration and internal-integration systems for the treatment of high-salinity mining wastewater and seawater desalination concentrate brine. The issues surrounding their cycling performance during batch operation, their anti-fouling potential in the presence of Mg2+/Ca2+ ions, and its specific operational cost were thoroughly investigated. The results suggest that the internal integration system demonstrates suitable stability during long-term operation under batch (cycling) mode. Nevertheless, the membrane exhibited inorganic scaling due to co-ion leakage at high current density. A highly pure NaOH was obtained through an internal integration process at a cost of 0.68 $/kg, outperforming the external integration system (98.96 %, 1.85 $/kg). The findings presented in this study offer valuable insights for the industrial application of BMSED technology in managing high salinity wastewaters.

Molecular weight insight into critical component contributing to reverse osmosis membrane fouling in wastewater reclamation

Molecular weight (MW) of organics was one of the important factors influencing membrane fouling propensity. This study identified critical foulants of reverse osmosis (RO) membranes in reclaimed water by MW fractionation. MW > 10 kDa component was identified as the critical fouling contributor (CFC) in secondary effluent (SE), which accounted for only 13 ± 5% of dissolved organic carbon (DOC) but contributed to 86 ± 11% of flux decline. Throughout 12-month monitoring, SE and MW > 10 kDa component showed a similar fouling variation tendency: apparently higher fouling potential in winter and lower in summer, while MW < 10 kDa component presented minor fouling changes. Morphology of membrane fouled by CFC characterized a smooth and thick foulant layer on membrane surface. CFC was mainly composed of proteins and polysaccharides, and a protein-polysaccharide-protein “sandwich” fouling layer structure was preferentially formed on membrane surface. extended Derjaguin–Landau-Verwey–Overbeek (xDLVO) analysis demonstrated that strong attractive interactions between CFC and membrane surface dominated the fouling process. Furthermore, computational fluid dynamics (CFD) simulation revealed strong filtration resistance of CFC, confirming its significant fouling potential. Dual effects including attractive interactions and advantageous ridge-and-valley surface appearance accounted for the significant fouling propensity of MW > 10 kDa component and glean valuable insights into RO fouling mechanisms of reclaimed water in practical application.

Controlling of irreversible fouling and mechanism in a hybrid ceramic membrane bioreactor (CMBR)-reverse osmosis (RO) process for textile wastewater reclamation

In this study, the fouling propensity of a hybrid ceramic membrane bioreactor (CMBR)-reverse osmosis (RO) process was investigated over a prolonged period using real textile wastewater effluent. Additionally, the effectiveness of in-situ ozonation for fouling mitigation was investigated. The results revealed that the CMBR-RO system achieved approximately 99.8 % removal of chemical oxygen demand and 97.4 % removal of total nitrogen. Despite this, soluble extracellular polymeric substances, particularly biopolymers and humics-like substances, remained in the system, resulting in irreversible fouling on the ultrafiltration (UF) membrane. The implementation of in-situ ozonation notably reduced ceramic membrane fouling by enhancing the filterability of larger macromolecules and eliminating inorganic/organic foulants from the membrane surface. Multiple modified fouling indexes were also utilized to evaluate the fouling potential of the RO feed water through size fractionation. It is worth noting that ozonation could pose a potential risk for subsequent RO membrane fouling due to the formation of low molecular weight neutrals, acids, and calcium- or silica- related inorganic-organic complexes. Overall, the integrated CMBR-RO system with in-situ ozonation exhibited excellent performance in producing clean water, achieving nearly 100 % removal of 20 Aromatic Amines. These findings underscore the viability of the CMBR-RO system as a practical and sustainable choice for the reclamation of textile wastewater.

Utilizing recycled pumice and oyster shell waste for cost-effective treatment to mitigate pollutants and toxicity in swine wastewater

Despite the abundant nutrients that could be reutilized in swine wastewater, inadequate wastewater management leads to excessive metals and organic matter, causing environmental impacts on aquatic and terrestrial ecosystems. In this study, we recycled waste pumice and oyster shells for the cost-effective treatment and reclamation of swine wastewater. The toxicity of the treated wastewater was assessed using the soil nematode Caenorhabditis elegans and Chinese cabbage Brassica rapa chinensis. Our findings showed significant removal of suspended solids, biochemical oxygen demand, chemical oxygen demand, total phosphorus, and heavy metals (As, Cu, Ni, and Zn) from the swine wastewater after treatment with pumice and oyster shells. Moreover, untreated wastewater significantly inhibited the germination of Chinese cabbage, a trend that was reversed in treated wastewater. Both treated and untreated swine wastewater stimulated the growth of Chinese cabbage. Additionally, untreated swine wastewater exhibited high toxicity to the growth and reproduction of C. elegans after 72 hours of exposure, whereas treated wastewater showed notably reduced toxicity. The recycled pumice and oyster shells significantly induced growth and showed no toxicity in Chinese cabbage. These results suggest that pumice and oyster shell waste can effectively reduce environmental toxicity in raw swine wastewater, offering a cost-effective wastewater treatment solution for small-scale pig farms.

Synergistic ferrate(VI) and chlorine for reclaimed water disinfection: Microbial control and chlorine decay mitigation

Chlorination is the most widely used disinfection technology due to its simplicity and continuous disinfection ability. However, the drawbacks of disinfection by-products and chlorine-resistant bacteria have gained increasing attention. Nowadays, ferrate (Fe(VI)) is a multifunctional and environmentally friendly agent which has great potential in wastewater reclamation and reuse. This study investigated synergistic Fe(VI) and chlorine technology for reclaimed water disinfection in terms of microbial control and chlorine decay mitigation. Specifically, synergistic disinfection significantly improved the inactivation efficiency on total coliform, Escherichia coli and heterotrophic bacteria compared to sole chlorination. Synergistic disinfection also exhibited superior performance on controlling the relative abundance of chlorine-resistant bacteria and pathogenic bacteria. In addition, the decay rate of residual chlorine was relatively lower after Fe(VI) pretreatment, which was beneficial for microbial control during the reclaimed water distribution process. Technical and economic analyses revealed that synergistic Fe(VI) and chlorine disinfection was suitable and feasible. Results of this study are believed to provide useful information and alternative options on the optimization of reclaimed water disinfection.

Alleviation of RO membrane fouling in wastewater reclamation plants using an enhanced acid-base chemical cleaning method

Membrane fouling has always been a critical constraint in the operation of the reverse osmosis (RO) process, and chemical cleaning is essential for mitigating membrane fouling and ensuring smooth operation of the membrane system. This paper presents an optimized chemical cleaning method for the efficient cleaning of RO membranes in full-scale applications. Compared to the regular cleaning method (cleaning with 0.1 % NaOH + 1 % ethylenediaminetetraacetic acid + 0.025 % sodium dodecyl benzene sulfonate followed by 0.2 % HCl), the optimized cleaning method improves the cleaning efficiency by adding sodium chloride to the alkaline cleaning solution and citric acid to the acid cleaning solution. Notably, the membrane flux recovery rate with the optimized cleaning method is 45.74 %, and it improves the cleaning efficiency by 1.65 times compared to the regular cleaning method. Additionally, the optimized cleaning method removes 30.46 % of total foulants (organic and inorganic), which is 2.11 times higher than the regular cleaning method. The removal of inorganic ions such as Fe, Ca, and Mg is significantly improved with the optimized cleaning method. For organic matter removal, the optimized cleaning method effectively removes more polysaccharides, proteins, and microbial metabolites by disrupting the complex structures of organic matter. Furthermore, it also changes the microbial community structure on the RO membrane surface by eliminating microorganisms that cannot withstand strong acids, bases, and high salt environments. However, Mycobacterium can adapt to these harsh conditions, showing a relative abundance of up to 84.13 % after cleaning. Overall, our results provide a new chemical cleaning method for RO membranes in full-scale applications. This method effectively removes membrane foulants and enhances the understanding of the removal characteristics of foulants on RO membrane surfaces by chemical cleaning.

Innovative hyper-thermophilic aerobic submerged membrane distillation bioreactor for wastewater reclamation

For the first time, a hyper-thermophilic aerobic (>60 °C) bioreactor has been integrated with direct submerged membrane distillation (MD), highlighting its potential as an advanced wastewater treatment solution. The hyper-thermophilic aerobic bioreactor, operating up to 65 °C, is tailored for high organic removal, while MD efficiently produces clean water. Throughout the study, high removal rates of 99.5% for organic matter, 96.4% for ammonia, and 100% for phosphorus underscored the impressive adaptability of microorganisms to challenging hyper-thermophilic conditions and a successful combination with the MD process. Despite the extreme temperatures and substantial salinity accumulation reaching up to 12,532 μS/cm, the biomass of microorganisms increased by 1.6 times over a 92-day period, representing their remarkable resilience. The distillation flux ranged from 6.15 LMH to 8.25 LMH, benefiting from the temperature gradient in the hyper-thermophilic setting and the design of the tubular submerged MD membrane module. The system also excels in pH control, utilizing fewer alkali and nutritional resources than conventional systems. Meiothermus, Firmicutes, and Bacteroidetes, the three dominant species, played a crucial role, showcasing their significance in adapting to high salinity and decomposing organic matter.

Identification of microbial groups in the aeration tanks of secondary wastewater treatment stage

Microbes are prevalent in wastewater, degrading organic matter that impact the environment. In recent years, wastewater treatment plants have been used to process treated water for domestic purposes, sustaining groundwater resources for the future. The current study assessed the present microbial species in the aeration tanks for the secondary wastewater treatment stage in the Sulaibiya Wastewater Treatment and Reclamation Plant, Kuwait. Biweekly wastewater samples were collected for a period of three months from October 2022 to December 2022 from the aeration tanks. The collected wastewater samples were analyzed for microbiological parameters including total coliform, fecal coliform, Salmonella, and E. coli. Further, the microbial species were identified using the Biolog Omnilog Instrument. The results indicated that a total of 45 bacterial species isolates were identified with the most dominant genus being Bacillus with twenty-one isolates. Though Bacillus is common in aeration tanks, the presence of Bacillus thuringiens/cereus is rare and their existence could be due to the change in climatic conditions such as rainfall, dust and wind. Therefore, the study recommends that all microbial groups should be identified at all treatment stages including, primary, secondary, tertiary, and advanced treatment stages to ensure the complete removal of microbes.