Conventional Wastewater Treatment Research Articles

The fate and transport of neonicotinoid insecticides and their metabolites through municipal wastewater treatment plants in South China

Neonicotinoid insecticides (NEOs) have gained widespread usage as the most prevalent class of insecticides globally and are frequently detected in the environment, posing potential risks to biodiversity and human health. Wastewater discharged from wastewater treatment plants (WWTPs) is a substantial source of environmental NEOs. However, research tracking NEO variations in different treatment units at the WWTPs after being treated by the treatment processes remains limited. Therefore, this study aimed to comprehensively investigate the fate of nine parent NEOs (p-NEOs) and five metabolites in two municipal WWTPs using distinct treatment processes. The mean concentrations of ∑NEOs in influent (effluent) for the UNITANK, anaerobic–anoxic–oxic (A2/O), and cyclic activated sludge system (CASS) processes were 189 ng/L (195 ng/L), 173 ng/L (177 ng/L), and 123 ng/L (138 ng/L), respectively. Dinotefuran, imidacloprid, thiamethoxam, acetamiprid, and clothianidin were the most abundant p-NEOs in the WWTPs. Conventional wastewater treatment processes were ineffective in removing NEOs from wastewater (−4.91% to −12.1%), particularly major p-NEOs. Moreover, the behavior of the NEOs in various treatment units was investigated. The results showed that biodegradation and sludge adsorption were the primary mechanisms responsible for eliminating NEO. An anoxic or anaerobic treatment unit can improve the removal efficiency of NEOs during biological treatment. However, the terminal treatment unit (chlorination disinfection tank) did not facilitate the removal of most of the NEOs. The estimated total amount of NEOs released from WWTPs to receiving waters in the Pearl River of South China totaled approximately 6.90–42.6 g/d. These findings provide new insights into the efficiency of different treatment processes for removing NEOs in current wastewater treatment systems.

Separation of Cellulose from Wastewater and Valorisation via Pyrolysis: A Case Study in the Czech Republic

Currently, the recovery of resources from urban wastewater (WW) represents a priority. On this topic, the potential recovery of cellulose for its subsequent reuse in different sectors is gaining interest. In this work, a large-size conventional wastewater treatment plant (WWTP) was selected as a case study. A preliminary mechanical treatment was used, with the aim of separating, quantifying, and characterizing cellulose in WW. The results suggest that the per-capita production of dry primary cellulosic sludge (D-PCS) is equal to 1.46 ± 0.13 kgD-PCS PE−1 y−1, with an average calorific value of 21.04 MJ kg−1DM. Cellulosic fibres have an average length of >100 µm and a thickness of 2–5 µm. The D-PCS was subsequently treated via medium-temperature pyrolysis; a total of 29.5% of the initial D-PCS was converted into pyrolyzed primary cellulosic sludge (P-PCS) and only 26% into pyrolytic gas. More than 44.5% of the dried cellulose can be converted into pyrolytic oil. Moreover, three different scenarios of recovery have been considered, and the impact of cellulose separation in terms of COD fluxes entering the WWTP and potential energy recovery has been studied. The results suggested that, in this case study, the potential separation of the primary cellulosic sludge from the influent water flux would have no significant impact on COD load entering the biological treatments and biogas production in the anaerobic digestion of the secondary sludge.

Efficiency and costs of household filters for the retention of fibrous microplastics from the laundry process in Germany

Synthetic fiber fragments from household washing are one of many types of microplastics that enter the environment. The potential and costs of fiber retention, using filters, were modeled for Germany. The high costs indicate that synergistic measures for the simultaneous retention of different types of microplastics from other sectors, such as road traffic, should not be overlooked in terms of cost-effectiveness. Around 500 tons of microplastics enter the wastewater from washing machines every year, of which, around 91 % is removed by conventional wastewater treatment. The separation costs amount to approximately EUR 2.2 million per ton. The widespread use of filters already available on the market in households could increase the proportion removed to 96 %. The costs for the additional separation amount to approximately 114 million EUR per ton. The use of filters would increase the costs for household washing by approximately 37 %.A comparison with the separation of tire wear reveals synergy potential. Around 20,000 tonnes of microplastics from tire wear are subjected to conventional wastewater treatment in the same way as the fibrous microplastics from the washing process. One starting point, for example, is that both types of microplastics can bypass the wastewater treatment plants and enter the environment as so-called overflow if the wastewater network is overloaded. The potential to reduce the input of microplastics, by reducing the release through overflows, far exceeds the savings potential of individual measures such as the installation of filters in households.

A comparative study with vermifilter and geofilter for domestic wastewater treatment and its Phyto-toxicity efficacy

The present study investigated the role of earthworms in pollutant removal and toxicity assay of domestic wastewater. An indigenous reactor (vermigratings as an active layer) was set up for 60 days with a hydraulic loading rate of 1 m3 / m2 -d and hydraulic retention time of 3.5 h to evaluate its performance. Removal of total suspended solids, total dissolved solids, biochemical oxygen demand, chemical oxygen demand, and sulfate was found to be 92 %, 93 %, 89 %, 86 %, and 63.43 %, respectively. The Phyto-toxicity test reveals a higher germination rate and plant growth with vermifilter effluent than with geofilter effluent and raw wastewater. Additionally, vermifilter achieved heterotrophic bacteria removal by 1.54-fold. Hence, treated effluent can be used for irrigation purposes. Overall, this study will establish a potential alternative to the conventional wastewater treatment system and achieve Sustainable Development Goals 6.

Naturalization of treated wastewater by a constructed wetland in a water-scarce Mediterranean region

The effluents from conventional wastewater treatment plants (WWTP), even if accomplishing quality regulations, substantially differ in their characteristics with those of waters in natural environments. Constructed wetlands (CWs) serve as transitional ecosystems within WWTPs, mitigating these differences and restoring natural features before water is poured into the natural environment. Our study focused on an experimental surface-flow CW naturalizing the WWTP effluent in a semiarid area in Eastern Spain. Despite relatively low pollutant concentrations entering the CW, it effectively further reduced settled organic matter and nitrogen. Dissolved organic matter (DOM) reaching the CW was mainly protein-like, yet optical property changes in the DOM indicated increased humification, aromaticity, and stabilization as it flowed through the CW. Flow cytometry analysis revealed that the CW released less abundant but more active bacterial populations than those received. MiSeq Illumina sequencing highlighted changes in the prokaryotic community composition, with phyla Proteobacteria, Bacteroidetes, Firmicutes, and Actinobacteria dominating the CW outflow. Functional prediction tools (FaproTax and PICRUSt2) demonstrated a shift towards microbial guilds aligned with those of the natural aquatic environments, increased aerobic chemoheterotrophs, photoautotrophs, and metabolic reactions at higher redox potentials. Enhanced capabilities for degrading plant material correlated well with changes in the DOM pool. Our findings emphasize the role of CWs in releasing biochemically stable DOM and functionally suited microbial populations for natural receiving environments. Consequently, we propose CWs as a naturalization nature-based solution (NBS) in water-scarce regions like the Mediterranean, where reclaimed discharged water can significantly contribute to ecosystem's water resources compared to natural flows.

Sustainable production of graphene quantum dots from rice husk for photo‐degradation of organochlorine pesticides

AbstractThe controlled synthesis of two‐dimensional nanocrystals of graphene particles instead of amorphous carbon quantum dots is highly challenging and requires tremendous efforts to optimize the reaction conditions. It has been observed that as a significant bio‐compatible zero‐dimensional material, graphene quantum dots are considered as a novel material for opto‐electronics, energy, biological and environmental applications. However, very few are known about their utilization in photocatalytic degradation of pesticides, especially organochlorine pesticides which are resistant to removal by conventional wastewater treatment methods. In this work, graphene quantum dots were produced from rice husk at relatively low temperatures, resulting in an average particle size of 3.3 nm. The high resolution transmission electron microscopy clearly showed the formation of spherical quantum dots having lattice fringes and the selected area electron diffraction pattern showed the crystallinity of the graphene quantum dots. A study of photodegradation of three highly toxic organochlorine pesticides namely, dichlorodiphenyl trichloro ethane, cypermethrin and fenvalerate were carried out using as‐synthesized graphene quantum dots from rice husk. Interestingly, all these pesticides were found to be degraded around 60 % to 70 % under visible light conditions. It confirmed that synthesized graphene quantum dots from rice husk can act as prominent photocatalyst for the degradation of pesticides and other pollutants.

Mathematical modeling of a conventional wastewater treatment plant in Gamasa- Egypt

Mathematical modeling of a conventional wastewater treatment plant in Gamasa- Egypt

Algal Membrane Bioreactors for Efficient Removal of Emerging Contaminants and Resource Recovery: Current Advances and Future Outlook

Emerging contaminants (ECs), whether of synthetic or natural origin, pose a significant environmental concern, particularly in the context of industrial wastewater. The Algae Membrane Photobioreactor (AMBR) has emerged as a promising technology for ECs remediation. AMBRs effectively remove contaminants due to its considerable flexibility, scalability and a huge surface area for pollutant adsorption. The productivity and efficiency of biomass are increased when it operates in regulated conditions, which minimizes land footprint. AMBR hold immense appeal in favoring integrated circular economy approach and its implementation could achieve the goals for carbon-neutrality and resource recovery by producing value-added products like biofuels, bioplastics, biochemicals, animal feed, biofertilizers and waste re-uses. However, addressing scalability, harvesting efficiency, membrane fouling, algal strain optimization, economic viability, and regulatory approval are some of the challenges faced in order to the advancement of AMBR technology. Life cycle assessments (LCA) and techno-economic assessments (TEAs) are crucial area of future research in implementation of AMBR at pilot scale. LCA evaluates the sustainability of AMBRs with those of conventional techniques. In contrast, TEA examines economic viability parameters like cost-effectiveness, by-product market potential, and policy implications for AMBR implementation. This review emphasizes AMBR's advantages over conventional wastewater treatment technologies in detail, focusing on algal physiology responsible for ECs removal. The innovations related to the design and configuration of AMBRs are also discussed. Several benefits of this technology via integrated circular paradigm are highlighted. Noteworthy pilot case studies, LCA, TEA, challenges and future perspective are spotlighted to underscore the compelling promise of this technology.

Novel 2D/2D S-scheme heterojunction photocatalyst for peroxymonosulfate activation enables ciprofloxacin ultrafast degradation: High-efficiency photogenerated carrier transport

Organic pollutants, such as ciprofloxacin (CIP), are ubiquitously detected in wastewater. However, their removal remains a challenge for conventional wastewater treatment technologies. Photocatalysis and peroxymonosulfate activation coupling are considered a promising strategy for the removal of recalcitrant organic pollutants. However, identifying optimal photocatalysts that can effectively couple with peroxymonosulfate activation and induce synergistic degradation of organic pollutants remains a challenge to be addressed. In this work, a novel S-scheme inorganic–organic heterojunction BiVO4/Cu-TCPP (BC) was fabricated. In situ X-ray photoelectron spectrum showed that the strong internal electric field of the S-scheme heterojunctions enabled efficient carrier transport. The generated photogenerated electrons could activate the peroxymonosulfate, which further promoted the separation of the carriers. The BC-vis-peroxymonosulfate system achieved 93.1% ciprofloxacin removal in 10 min with apparent rate constants k of 0.2426 min−1, which is larger than most reported peroxymonosulfate systems. Electron paramagnetic resonance spectra and liquid chromatography mass spectrometry demonstrated that the synergistic coupling of S-scheme heterojunction with peroxymonosulfate activation significantly improved the catalytic activity of the reaction system and enabled rapid CIP removal via both radical and nonradical pathways. The BC-vis-peroxymonosulfate system demonstrated ultra-fast removal of other quinolone antibiotics and organic pollutants and strong environmental adaptability under various conditions, suggesting its great potential for practical application. This study provides new insights for the design of efficient S-scheme heterojunction coupled peroxymonosulfate activation for environmental remediation.

Degradation of imidazolium-based ionic liquids by UV photolysis and pulsed corona discharge: The effect of persulfates addition

Ionic liquids (ILs) are salts with exceptional properties important for future development, although potentially hazardous for humans and aquatic life due to their high aqueous solubility and toxicity. Biodegradation of ILs depends on the anion nature and cation structure: many ILs are not readily degraded during conventional wastewater treatment, thus requiring alternative cost-effective and energy-efficient solutions. In this research, the degradation of aqueous imidazolium-based ILs by pulsed corona discharge (PCD) and UV photolysis combined with persulfates was studied, using peroxymonosulfate (PMS) and peroxydisulfate (PDS) as extrinsic oxidants. 1-Ethyl-3-methylimidazolium chloride ([Emim][Cl]), 1-methyl-3-octylimidazolium chloride ([Omim][Cl]), and 1-ethyl-3-methylimidazolium bromide ([Emim][Br]) were chosen as imidazolium-based ILs with different alkyl chain lengths and anions in oxidation experiments under variable operation factors - pH, concentrations of persulfates, pulse repetition frequency in PCD. Pulsed corona discharge has previously shown high energy efficiency in the degradation of micropollutants but has not yet been applied to ionic liquids. The experimental results showed the ability of PCD, PCD/oxidant and UV/oxidant combinations to completely degrade the ILs with the degradation rates in descending order [Emim][Cl] > [Omim][Cl] > [Emim][Br], indicating an impact of both the alkyl chain length and the type of anion on the oxidation rate. The strong activation of persulfates was observed in UV/oxidant combinations, whereas PCD demonstrated the effect of persulfates addition between slight acceleration and moderate deceleration of oxidation dependent on the concentration of extrinsic oxidants. The addition of the sulfate radicals’ scavenger, however, showed the presence of those in all combinations indicating a certain replacement of PCD-generated reactive oxygen species with secondary reactants formed from persulfates. The unassisted PCD and UV/PDS combination demonstrated similar energy efficiencies of about 54 and 26 mmol kWh−1 for [Emim][Cl] and [Emim][Br] degradation, respectively, while for [Omim][Cl] the UV/PDS combination showed energy efficiency 1.42 times higher than unassisted PCD.

Degradation of trimethoprim by advanced oxidation process using UV/TiO2 and H2O2: Kinetic and economic aspects

AbstractTrimethoprim (TMP) is an effective antibiotic for treating many different infections, but it can lead to water pollution and pose a threat of generating antibiotic‐resistant bacteria through waste in the drug manufacturing process, use, and excretion of humans as well as animals. Due to its strong and non‐selective oxidizing ability, advanced oxidation processes (AOPs) utilizing UV/TiO2 and H2O2 are more efficient in removing them than conventional wastewater treatment. This work investigates TMP degradation in different water substrates by AOPs using UV/TiO2 and H2O2. The results show that the apparent reaction rate constant to the TMP's degradation in the de‐ion water matrix is 0.0379; 0.1937; and 0.209 min−1 for UV/TiO2, UV/H2O2, and UV/TiO2/H2O2 processes. The rate of degradation of TMP in hospital wastewater is lower than that of lake water and de‐ion water. The major intermediate products obtained from the degradation of TMP in de‐ion water by UV/TiO2/H2O2 process were recognized as C14H19O4N4 (m/z: 307), C5H7ON4 (m/z: 139), and C5H6O2N4 (m/z: 155). Finally, the cost of TMP treatment in de‐ion water by several AOPs using photocatalyst and hydrogen peroxide was calculated, it is 0.88 $/m3 for UV/H2O2; 33.01 $/m3 for UV/TiO2 process, and 18.77 $/m3 for UV/TiO2/H2O2 process.

Porous Fe-Porphyrin as an Efficient Adsorbent for the Removal of Ciprofloxacin from Water.

Antibiotics are widely used in medicine, but they are not fully metabolized in the body and can end up in wastewater. Conventional wastewater treatment methods fail to completely remove antibiotic residues, which can then enter rivers and streams. Adsorption is a promising technique for removing antibiotics from wastewater, even at low concentrations. The successful one-pot synthesis of an adsorbent, iron-containing porphyrin-based porous organic polymer (Fe-POP), was achieved through the reaction of pyrrole groups and terephthalaldehyde in the presence of FeCl3. Characterized by a substantial BET surface area of 597 m2 g-1, Fe-POP was systematically investigated for its adsorption potential in the removal of the antibiotic Ciprofloxacin (CIP) from aqueous solutions. By systematic variation of key parameters, including pH, adsorbent loading, and CIP concentration, the adsorption conditions were optimized. Under the optimal conditions at pH = 3, CIP concentration of 5 ppm, and 25 mg of Fe-POP, the maximum adsorption capacity reached an impressive 263 mg g-1. The robust adsorption behavior was elucidated through the fitting of experimental data to the Langmuir adsorption isotherm (R2 = 0.962) and the pseudo-second-order kinetic model (R2 = 0.999) with lower error values. These models suggested that the adsorption process predominantly involved chemical interactions between CIP molecules and the Fe-POP surface. Fe-POP exhibited a robust structure with a high adsorption capacity, showcasing its efficacy in removing CIP contaminants from water. Therefore, Fe-POP can be considered a valuable adsorbent for water treatment applications, specifically for antibiotic removal.

The Application of an Upflow Anaerobic Sludge Blanket Reactor in the Treatment of Brewery and Dairy Wastewater: A Critical Review

Brewery (BW) and dairy (DW) wastewater are two types of agro-industrial wastewater that are generated in large amounts and, therefore, should be treated effectively and in an environmentally beneficial manner. Both these wastewater types are characterized by a high COD, BOD5, and nutrient content, and conventional wastewater treatment methods such as an activated sludge process may prove to be inefficient due to the possibility of foaming, large biomass production, low activity at low temperatures, and risk of overloading the reactor with a load of organic pollutants. In the context of the described difficulties, anaerobic processes seem to be the best alternative. An interesting research area is the co-digestion of these wastewaters. However, this research direction, so far, has not been frequently reported. Given the gap in the current knowledge, this literature review aims to assess the possibility of BW and DW digestion in anaerobic reactors and provide up-to-date data on the post-treatment methods of effluent generated after the anaerobic digestion process. Despite numerous advantages, anaerobic treatment often requires post-effluent treatment to complete the treatment cycle.

AN OVERVIEW ON THE SYNTHESIS OF PHOSPHORYLATED CHITOSAN DERIVATIVES FOR THE ADSORPTION OF EMERGING CONTAMINANTS IN WATER

Safe water for human consumption and for aquatic life is of paramount importance. The emergence of new kinds of contaminants like surfactants, pharmaceutical drugs, hormones, foods and additives, laundry detergents, etc., are posing new and serious challenges to the conventional primary and secondary waste water treatment, because of the inability to remove or degrade these toxic pollutants efficiently and hence, the need for cost effective tertiary treatment method. Adsorption is a promising method worldwide for the removal of emerging contaminants, since it is highly-efficient and has a simple operating system. This review seeks to investigate the suitable preparation methods of soluble phosphorylated chitosan derivatives as efficient adsorbent for effective removal of emerging contaminants in water. Hence, the goal of this study, is to review some synthesis of the phosphates of chitosan under various chemical conditions to produce soluble chitosan derivatives which can be effectively used for the removal of emerging contaminants in water by adsorption technique.

Development of an efficient, low-operating-pressure graphene oxide/polyethersulfone nanofiltration membrane for removing various water contaminants

Conventional wastewater treatment technologies tend to be high-capex, energy-intensive solutions that lack specificity for different pollution classes, and do not lend themselves to wide-scale deployment, particularly in areas of the world where industrial wastewater discharge is a significant environmental problem. In tandem, solid waste pollution arising, particularly plastic containing waste, is a persistent and serious pollution issue. This work focuses on the concept of "waste treating waste" and a multidisciplinary effort ranging from materials science and environmental management to sustainable water treatment, in addition to production of graphene oxide from mineral water waste bottles using a simple synthetic procedure that can be economically scaled up for use as a cost-effective adsorbent. Prepared graphene oxide was supported on a polyethersulfone (PES) membrane, and batch filtration studies were performed to examine its performance in the removal of methylene blue (MB) dye, Gentimicin sulphate (GMS) antibiotic, and Na2SO4 and MgSO4 salts from an aqueous solution. Operating parameters such as initial pollutant concentration, time, and solution pH were investigated and optimized using a response surface methodology (RSM) model. The results confirm the significant efficiency of the filtration process, with a maximum rejection of about 91% for MB, 93% for GMS, 67% for Na2SO4, and 64% for MgSO4, with maximum water flux of 1322, 1367, 1225, and 1059 LMH, respectively. Density functional theory calculations were considered for the GO, PES membrane, and GO/PES membrane with a GGA/PBE optimization level. Adsorption annealing locator analysis was performed for the GO/PES membrane, and the process was recalculated for MB as adsorbate. In conclusion, the adsorption effect employing produced GO/PES membrane is the most important removal, followed by Donnan exclusion and steric hindrance effect. Therefore, it is possible to build new eco-friendly membranes for nanofiltration that are affordable, stable, and effective in removing various pollutants from water systems.

Performance analysis of distillate quality in solar still using culinary discharge

ABSTRACT The scarcity of clean water is a pressing global problem resulting from limited freshwater resources and substantial sewage discharge. It is essential to develop cost-effective and straightforward methods for converting wastewater into potable water to ensure the long-term sustainability of the human population. In this study, we introduce a simple and efficient technique that combines a single slope solar still (SSSS) with a sand bed filtration system. We evaluated the effectiveness of this technique by examining various water quality parameters, including pH, total dissolved solids, electrical conductivity, turbidity, alkalinity, hardness, biochemical oxygen demand, chemical oxygen demand, phosphate, nitrate, and E. coli, for kitchen wastewater (KWW), settled kitchen wastewater (SKWW), and borewell water (BW). Our results showed that the SSSS process successfully removed impurities and bacteria via solar evaporation, resulting in significant improvements in all water quality parameters. The SKWW demonstrated the highest efficiency of 40%, with a water depth of 1 cm and a daily freshwater yield of 3.1 Lm-2. The SSSS process offers several advantages over conventional wastewater treatment methods, including high performance, ease of use, portability, and low cost, making it a promising solution for obtaining clean water in remote areas.

Pharmaceuticals in the Water: Emerging Concerns and Innovative Remediation Solutions

Abstract: Pharmaceutical contamination, resulting from the discharge of active pharmaceutical ingredients (APIs) and other related compounds into the water, has become a growing concern due to its potential adverse effects on ecosystems and human health. This review article aims to examine the many facets of pharmaceutical contamination and highlight the most recent developments in its remediation. The effects of pharmaceuticals, sources, and pathways of pharmaceutical contamination, as well as the difficulties in detecting and evaluating its toxicities, have been included in the present manuscript. Nowadays various remediation strategies are employed to mitigate pharmaceutical contamination in water. Conventional wastewater treatment techniques, including activated sludge processes and membrane filtration, are effective in removing a portion of the pharmaceutical compounds. However, advanced oxidation processes such as ozonation and photocatalysis have shown promising results in enhancing the degradation of recalcitrant APIs. Nanotechnology-based approaches, such as the use of nanoparticles for adsorption and degradation, and bioremediation methods utilizing microbial degradation, enzymatic processes, and phytoremediation, offer potential future directions for efficient and sustainable remediation. This review describes the most recent developments, current status, and potential research directions with the future prospects of pharmaceutical pollutants.

Sustainability analysis of primary wastewater treatment by willow plantations in Québec

Wastewater treatment is a necessary step to avoid environmental impacts of water consumption and usage. Traditional approaches are expensive and are limited to developed countries. Phytofiltration using fast-growing trees and shrubs like willows potentially offer an alternative. This paper aims to determine if wastewater treatment using phytofiltration can provide complementary environmental and economic benefits for rural communities in a Nordic climate such as the province of Québec, Canada. It looks at different perspectives of the wastewater treatment solution in a local and rural context. Based on life cycle analysis (LCA) and life cycle cost analysis (LCC), we found that, for an exemplar Québec municipality, the conventional wastewater treatment scenario impacted more on climate change, ecosystem quality and human health than the two phytofiltration of wastewater scenarios studied, where impact is highly dependant on the biomass valorization. The net present cost of the phytofiltration scenarios were lower than typical conventional treatment in Québec. For a biomass producer, conventional biomass production had the highest environmental impact on ecosystem quality, while biomass production from phytofiltration had the highest environmental impact on climate change, human health, and resources. We demonstrate that the phytofiltration is a viable and multifunctional technology that could provide good incentives for a local biomass value chain. it allows to both alleviate wastewater treatment burden and provide affordable biomass for bioenergy development for rural communities. Mobilizing local stakeholders will be key to make phytofiltration an alternative solution for both environmental burden alleviation and rural economic development.

Fuzzy Approach for Evaluating Critical Factors in the Design and Construction of Conventional Wastewater Treatment Plants

Fuzzy Approach for Evaluating Critical Factors in the Design and Construction of Conventional Wastewater Treatment Plants

The role of algae-based wastewater treatment systems: A comprehensive review

Algae-based wastewater treatment systems have gained significant attention as sustainable and efficient solutions for nutrient removal, organic pollutant degradation, and biomass production. This comprehensive review explores the role of algae-based systems in wastewater treatment, covering key aspects such as nutrient uptake mechanisms, cultivation techniques, system design considerations, and environmental sustainability implications. Algae offer unique advantages for wastewater treatment, including high nutrient removal rates, CO2 sequestration, and the production of valuable biomass for biofuel production and nutrient recycling. Various cultivation methods, including open ponds, raceways, photobioreactors, and wastewater treatment wetlands, are evaluated for their suitability in different wastewater treatment scenarios. The integration of algae-based systems with conventional wastewater treatment processes, such as activated sludge and membrane bioreactors, is discussed to enhance treatment efficiency and resource recovery. Furthermore, the environmental sustainability of algae-based systems, including carbon footprint, water footprint, and ecosystem impacts, is assessed to identify opportunities for mitigating environmental impacts and promoting ecosystem resilience. Future research directions in algae-based wastewater treatment systems, such as optimization of cultivation conditions, development of novel algal strains, and techno-economic analysis of large-scale implementation, are proposed to address remaining challenges and accelerate the adoption of algae-based technologies in wastewater treatment practices. Overall, this review provides valuable insights into the role of algae-based systems as sustainable and versatile tools for wastewater treatment, highlighting their potential to address the growing challenges of nutrient pollution and water scarcity in the 21st century.