Alternative Wastewater Treatment Research Articles

Exploring Moringa oleifera: Green Solutions for Sustainable Wastewater Treatment and Agricultural Advancement

Increasing concerns over water pollution have driven the search for sustainable wastewater treatment alternatives. This study evaluates the effectiveness of two coagulants derived from Moringa oleifera seeds–powder and extract–as sustainable solutions for wastewater reuse in agriculture. Comparative experiments were conducted using aluminum sulfate, a conventional coagulant, at various doses under controlled laboratory conditions. The results demonstrated that both M. oleifera-based coagulants were highly effective, achieving turbidity reductions of 97% and 99%, respectively. Notably, the powder form required lower doses than the extract but had longer sedimentation times. Further detailed analyses at optimized doses (500 mg/500 mL for powder and 12.5 mL/500 mL for extract) met international standards for wastewater quality in agricultural irrigation. Comprehensive analyses encompassing pH, turbidity, COD, BOD5, TSS, DO, conductivity, NO2−, NO3−, SO42−, PO43−, and fecal and total coliforms consistently adhered to stringent criteria, confirming the effectiveness of M. oleifera-derived coagulants. These findings highlight the potential of M. oleifera in wastewater treatment, offering sustainable solutions to environmental challenges and enhancing food security in resource-limited regions. Our research supports the broader adoption of these eco-friendly alternatives, which could significantly reduce water scarcity and promote sustainable agricultural practices, addressing critical environmental concerns.

Decentralized sanitation alternatives in cities of the global south—A case of constructed wetlands in Bulawayo, Zimbabwe

Constructed wetlands have emerged as a sustainable alternative for decentralized wastewater treatment in developing countries which face challenges with urbanization and deteriorating infrastructure. This paper discusses the key factors affecting the implementation of constructed wetlands in developing countries. A case study research design was adopted, which focused on Bulawayo, Zimbabwe. A mixed-method approach was adopted for the study. Spatial analysis was conducted to identify potential sites for constructed wetlands in the city of Bulawayo. Semi structured interviews were conducted, with relevant stakeholders, such as town planners, civil engineers, NGO representatives, community leaders, and quantity surveyors. The findings reveal that political reforms, public acceptance, land availability, and funding are crucial for the successful implementation of constructed wetlands. Additionally, four sites were identified as the most favorable preliminary locations for these systems. The paper captures all the key factors relevant to the implementation of constructed wetlands (CWs) with a closer look at policy and the role it plays in the adoption of decentralized wastewater treatment systems. Formulating policy around the decentralized sanitation systems was considered imperative to the success of the systems whether in implementation or in operation. The paper adds to knowledge in the subject of sustainable wastewater treatment alternatives for developing countries. However, further research can be conducted with a different methodology to ascertain the applicability of the systems in developing urban cities considering other important aspects in the implementation of wastewater treatment systems.

Septic tanks as a pathway for emerging contaminants to the aquatic environment–Need for alternative rural wastewater treatment?

Septic tanks (STs) as a decentralised approach to community wastewater treatment were investigated as a pathway for emerging contaminants (ECs) entering the aquatic environment. A broad range of ECs were examined in five community STs (population equivalents 217–475) and receiving rivers in Scotland over 12 months. All 68 studied ECs were detected at least once in ST influent or effluent at a broad concentration range from ng L−1 – μg L−1 which can surpass freshwater predicted no-effect concentrations. Pharmaceuticals with acute use, such as antibiotics and antifungals, had high monthly variability and concentrations can exceed those previously found in centralised wastewater treatment works. Differences between the STs demonstrate the impact of localised prescription and population behaviour on EC concentrations. The similarities in concentrations between influent and effluent, suggest limited or no removal of ECs in STs. Hence, dilution of the discharges is required to mitigate environmental risk. Although the contribution of ECs sorbed to suspended solids to the total EC concentration was generally small (<10%), higher contributions (>30%) were observed for fluoroquinolone antibiotics (ofloxacin and ciprofloxacin), antidepressants (fluoxetine), and antifungals (clotrimazole). A wide range of ECs were also detected in rivers upstream and downstream of the ST discharge points, and concentrations increased by up to 95% downstream. In general, risk quotients (RQs) in the rivers were low, indicating small risk for the environment. However, higher RQs (>1) were found for ibuprofen, diclofenac and ciprofloxacin in a few samples. Therefore, reducing their concentration by improving ST performance or through sustainable medicines use may be needed at low dilution locations to mitigate any risk.

Advancements in Biopolymer‐Derived Graft Copolymers: A Comprehensive Review on Their Application in Sustainable Wastewater Treatment

ABSTRACTRising concerns over water pollution and the depletion of non‐renewable resources have propelled the exploration of eco‐friendly and sustainable wastewater treatment alternatives. Biopolymer‐derived graft copolymers emerge as a promising solution, offering biodegradability, cost‐effectiveness, versatility, and enhanced functionality. This review provides a comprehensive overview of the latest developments in utilizing these copolymers as eco‐friendly flocculants for wastewater treatment. It covers synthesis methods for functionalized biopolymer‐based flocculants, diverse flocculation mechanisms, and their efficacy in solid–liquid separation. The article explores applications for removing pollutants, emphasizing biodegradability, cost‐effectiveness, and versatility. Special attention is given to the environmental impact, critically analyzing how these copolymers contribute to sustainable water treatment practices. The review also discusses potential future prospects and advancements in addressing global water pollution challenges using biopolymer‐derived graft copolymers.

Assessing the current situation of constructed wetland-microbial fuel cells as an alternative power generation and wastewater treatment in developing countries

Developing countries facing population growth and increased energy demand present simultaneous challenges regarding wastewater treatment and electricity supply. Constructed wetland-microbial fuel cells (CW-MFCs) offer a dual solution to the challenges of insufficient electricity and wastewater treatment by integrating indigenous plant species. CW-MFCs provide sustainable power generation and wastewater treatment. This approach can enhance sustainability and foster a circular economy by utilising plant-derived byproducts as an added product. Current research indicates various novel designs for effective wastewater treatment and potential power generation. Future studies focusing on rural settings and upscaling operations can apply advanced techniques like mass spectrophotometry and metagenomics to refine the technology for grid use. Developing CW-MFC technology will catapult the idea of developing a robust strategy for addressing power supply and sanitation issues in developing regions. This will also aid in continuous research into system optimisation and microbial communities, aiding long-term viability.

Recent Advances in Magnetic Feˣ⁺/TiO₂ Microfibers for Wastewater Treatment as Climate Change Mitigation

Chemical dyeing and finishing processes used in the clothing and textile industries are among the main contributors that can increase the impact of climate change. Photocatalysis using nanosized titanium dioxide (TiO2) has been continuously developed as a promising technology for purifying dye wastewater into simpler and environmentally friendly components. In addition, the decoration of iron cations (Fe2+) and (Fe3+) increases the reusability of the photocatalyst due to their magnetic properties, which are easy to collect for the recycling process. Magnetic Fex+/TiO2 microfibers have been successfully prepared using a hydrothermal method using titanium dioxide in an alkaline solution. Cations were added into the solution with the different molar ratios of Ti/Fex+ to produce Fe2+/TNW and Fe3+/TNW, respectively. Photocatalysis activity test using magnetic Fex+/TNW was carried out using methylene blue in a reactor equipped with an incandescent bulb lamp representing solar light. The results showed that adding the cations resulted in a new shape of palm tree leaves, like titanate microfibers. Controlling the cation’s molar ratio produces the magnetic Fex+/TNW with a 50-150 µm length. SEM images of each material presented the uniformly elongated shape and aggregated on one side morphology. In addition, paramagnetic properties indicate that magnetic Fex+/TNW can be easily separated from the dispersion in less than 1 minute using an external magnet. A photocatalysis activity test of magnetic Fex+/TNW was performed by calculating the percent degradation of methylene blue with variations in irradiation time in visible light conditions. The result showed the effectiveness of photodegradation of methylene blue was significantly increased in materials with 3.3 molar ratios of both Ti/Fe2+ and Ti/Fe3+ with a percent degradation reaching 79% and 70%, respectively, in 5 hours. In conclusion, magnetic Fex+/TNW is introduced as an alternative dye wastewater treatment technology that has reusable properties and works well on sustainable energy sources of solar light.

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

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

Synthesis and Characterization of Composite WO3 Fibers/g-C3N4 Photocatalysts for the Removal of the Insecticide Clothianidin in Aquatic Media.

Photocatalysis is a prominent alternative wastewater treatment technique that has the potential to completely degrade pesticides as well as other persistent organic pollutants, leading to detoxification of wastewater and thus paving the way for its efficient reuse. In addition to the more conventional photocatalysts (e.g., TiO2, ZnO, etc.) that utilize only UV light for activation, the interest of the scientific community has recently focused on the development and application of visible light-activated photocatalysts like g-C3N4. However, some disadvantages of g-C3N4, such as the high recombination rate of photogenerated charges, limit its utility. In this light, the present study focuses on the synthesis of WO3 fibers/g-C3N4 Z-scheme heterojunctions to improve the efficiency of g-C3N4 towards the photocatalytic removal of the widely used insecticide clothianidin. The effect of two different g-C3N4 precursors (urea and thiourea) and of WO3 fiber content on the properties of the synthesized composite materials was also investigated. All aforementioned materials were characterized by a number of techniques (XRD, SEM-EDS, ATR-FTIR, Raman spectroscopy, DRS, etc.). According to the results, mixing 6.5% W/W WO3 fibers with either urea or thiourea derived g-C3N4 significantly increased the photocatalytic activity of the resulting composites compared to the precursor materials. In order to further elucidate the effect of the most efficient composite photocatalyst in the degradation of clothianidin, the generated transformation products were tentatively identified through UHPLC tandem high-resolution mass spectroscopy. Finally, the detoxification effect of the most efficient process was also assessed by combining the results of an in-vitro methodology and the predictions of two in-silico tools.

Integrating artificial intelligence modeling and membrane technologies for advanced wastewater treatment: Research progress and future perspectives

Membrane technologies have become proficient alternatives for advanced wastewater treatment, ensuring high contaminant removal and sustainable resource recovery. Despite significant progress, ongoing research efforts aim to further optimize treatment performance. Among the challenges faced, membrane fouling persists as a relevant obstacle in membrane technologies, necessitating the development of more effective mitigation strategies. Mathematical models, widely employed for predicting treatment performance, generally exhibit low accuracy and suffer from uncertainties due to the complex and variable nature of wastewater. To overcome these limitations, numerous studies have proposed artificial intelligence (AI) modeling to accurately predict membrane technologies' performance and fouling mechanisms. This approach aims to provide advanced simulations and predictions, thereby enhancing process control, optimization, and intensification.This literature review explores recent advancements in modeling membrane-based wastewater treatment processes through AI models. The analysis highlights the enormous potential of this research field in enhancing the efficiency of membrane technologies. The role of AI modeling in defining optimal operating conditions, developing effective strategies for membrane fouling mitigation, enhancing the performance of novel membrane-based technologies, and improving membrane fabrication techniques is discussed. These enhanced process optimization and control strategies driven by AI modeling ensure improved effluent quality, optimized resource consumption, and minimized operating costs. The potential contribution of this cutting-edge approach to a paradigm shift toward sustainable wastewater treatment is examined. Finally, this review outlines future perspectives, emphasizing the research challenges that require attention to overcome the current limitations hindering the integration of AI modeling in wastewater treatment plants.

Application of Nanostructured Materials for the Remediation of Microbes Contaminated Water and Sustainable Water Treatment

Regardless of whether pollution originates from inorganic sources such as heavy metals, or organic waste such as industrial discharges; it poses a grave threat toward human health and environmental equilibrium. Air and water quality, soil health, ecosystem integrity—all can suffer negative impacts due to these pollutants with far-reaching effects on both public health and our surroundings. To alleviate this pervasive problem effectively: comprehensive strategies must be implemented that encompass strict regulatory measures; advocate for sustainable industrial practices – promoting environmentally conscious behaviors is also key, and recent decades have seen a marked rise in pollutants in water sources. Human existence depends on having access to clean water, yet numerous sources are now seriously contaminated. Fortunately, using several cutting-edge methods, nanotechnology provides intriguing and useful options for wastewater cleaning. Numerous pollutants, including germs, sediments, and dangerous chemicals like Mercury and Arsenic, may be removed using nanotechnology. The development of wastewater treatment alternatives is being aided by cutting-edge nanotechnology, which has the potential to improve the reuse of water, recycling, and restoration. This not only improves the quality and durability of the water over the long term, but also assures future generations will have access to it. Diverse procedures and strategies are now used in the field of water purification, many of which use nanomaterials. Nanofiltration is a particularly effective and straightforward technique. Low pressure water is used in this method to flow through nanofiltration filters; these filters may be quickly cleaned by simply back-flushing. Utilizing carbon nanotubes, which are recognized for their efficiency in eliminating a wide range of water contaminants because of their incredibly smooth interiors, is another benefit of nanofiltration. When compared to traditional microstructure materials, nanostructured materials, such as Ag (silver), Au (gold), metal oxides, and CNTs (carbon nanotubes), provide several advantages in the purification of water. They are excellent alternatives for tackling the urgent problems caused by water contamination because of their increased surface area and exceptional qualities. In conclusion, the use of nanomaterials in water filtration, such as Ag, Au, metal oxides, and CNTs, marks a huge step towards protecting our planet's most valuable resource. We can create a sustainable future where everyone has access to clean, secure drinking water by using the potential of nanotechnology.

Effect of Photocatalytic Pretreatment on the Membrane Performance in Nanofiltration of Textile Wastewater

Traditional methods like biological treatment, flocculation-coagulation, adsorption, and advanced oxidation are commonly employed for textile wastewater treatment, but their sustainability is hindered by issues such as the adverse impact of textile wastewater on microorganisms and the requirement for substantial chemical usage. In response to increasingly stringent legal discharge standards, membrane technologies are emerging as prominent alternatives for effective textile wastewater treatment. The application of photocatalysis as a pretreatment to improve effluent quality and treatment performance has shown effective results in the treatment of textile wastewater by nanofiltration (NF). However, innovative solutions are needed to improve the efficiency of UV photocatalytic reactors. Here, the TiO2/halloysite nanotube (HNT) photocatalyst was shown to completely remove dyes under UV illumination. Two wastewater samples from photocatalytic (PC) pretreatment were treated using innovative NF membranes with different contents. The study examined the impact of PC pretreatment on the flux of wastewater from a textile factory heat recovery tank, which increased from 18.32 to 27.63 L/m2.h. The membranes achieved > 98% removal in COD, while bare membrane achieved 95% removal in conductivity. The addition of s-DADPS as monomer and HNT as nanoparticles to the membranes with different compositions affected the cross-linking in the TFC layer. During the tests conducted on the water extracted from the dyeing tank, the color was completely eliminated without any loss of flux. Additionally, improvements in COD removal were observed.

Use of Plant-Based Coagulants Sorghum Bicolor and Trifolium Repens as Future Alternatives for Textile Wastewater Treatment Based on Computational Model

Sorghum bicolor and Trifolium repens extracts as plant coagulants can be used for wastewater treatment instead of chemical coagulants. This study investigates the effects of pH and coagulant dose on COD and turbidity reduction by natural coagulants. In the optimum treatment conditions of 100 mg/L coagulant dose and pH 7, high turbidity (81.34%), and COD reduction (62%) (compared with alum and FeCl3) were obtained. The percentage of COD reduction is higher in Trifolium repens than the other plant coagulant, and the percentage of turbidity reduction is higher in Sorghum bicolor. FT-IR spectra were performed on the plant extracts to identify the existing factors in active extracts. Also, outlet COD and turbidity values can be predicted and calculated according to computational equation in similar treatment systems. It should be mentioned that the only applied solvent for extracting the natural coagulant seeds was distilled water, and none of the other solvents such as NaCl and NaOH were used. According to the results, the characteristics of the treated effluents by the plant extracts make them appropriate alternatives for textile wastewater treatment.

Characterization and Proposal of Technologies for The Treatment of Domestic Sewage in Ilha Grande Bay – RJ

Objective: To characterize the situation of sanitary wastewater discharge in the hydrographic basins draining into the Baía da Ilha Grande (BIG) and to propose wastewater treatment alternatives based on the literature on decentralized solutions. Theoretical framework: The BIG has been experiencing negative environmental impacts due to the urbanization process in the region, mainly due to the irregular discharge of domestic wastewater into the environment. Method: The methodology was developed in two stages, with stage 1 involving data collection from available data in the 2017 Wastewater Atlas, and stage 2 focusing on identifying the most appropriate treatment technologies for this study from the fifteen options evaluated. Results and conclusion: The characterization revealed that municipalities within the BIG are already using decentralized solutions for domestic wastewater treatment, albeit below the national average coverage rates (18-54%). The five most promising technologies identified were Septic Tanks, Compact UASB, Biodigesters, Compartmentalized Anaerobic Reactors, and Integrated Biosystems. It is concluded that the communities have a sanitation deficit and show potential for implementing decentralized solutions. Implications of the research: The study helped develop strategies for decision-makers to select the most appropriate wastewater treatment technologies to meet local needs. It also served as a model for scientific studies in other locations. Originality/value: This study aligns with the Sustainable Development Goals (SDGs), particularly SDG 6, by presenting decentralized solutions as a promising pathway to universalizing household wastewater treatment in developing countries.

Biodegradability and bioavailability of dissolved substances in aquaculture effluent: Performance of indigenous bacteria, cyanobacteria, and green microalgae

Aquaculture is a controlled aquatic farming sector and one of the most important human food sources. Fish farming is one of the predominant, fast-growing sectors that supply seafood products worldwide. Along with its benefits, aquaculture practices can discharge large quantities of nutrients into the environment through non-treated or poorly treated wastewater. This study aims to understand the nutrient composition of fish wastewater and the use of indigenous bacteria, cyanobacteria, and microalgae as an alternative biological treatment method. Wastewater samples from a local fish farming facility were collected and treated using six different species of cyanobacteria and microalgae include Chroococcus minutus, Porphyridium cruentum, Chlorella vulgaris, Microcystis aeruginosa, Chlamydomonas reinhardtii, and Fischerella muscicola. All the samples were incubated for 21 days, and the following parameters were measured weekly: Chemical oxygen demand (COD), phosphate, total dissolved nitrogen, and dissolved inorganic nitrogen. In addition, dissolved organic nitrogen (DON), bioavailable DON (ABDON), and biodegradable DON (BDON) were calculated from the mass-balance equations. Colorimetric and digestive methods were used for the parameter measurements. The results showed that C. reinhardtii reduced the soluble COD concentration by 74.6 %, DON by 94.3 %, and phosphorous by more than 99 %. Moreover, M. aeruginosa, and C. minutus significantly reduced inorganic nitrogen species (>99 %). This alternative fish wastewater treatment method was explored to gain insight into fish wastewater nutrient composition and to create a sustainable alternative to conventional fish wastewater treatment methods.

Seaweed-based biosorbent for the removal of organic and inorganic contaminants from water: a systematic review

Inadequately treated or untreated wastewater contributes substantially to the discharge of undesirable and hazardous substances into aquatic environments. Serious concerns are raised when certain pollutants become persistent and bioaccumulative upon release into the environment. Despite the existence of alternative wastewater treatment technologies, adsorption has consistently demonstrated its efficacy in the treatment of wastewater originating from diverse industrial sources. Adsorption is selected as the optimal method due to its numerous benefits, which include greater efficacy, reduced cost, and convenient accessibility in comparison to alternative treatments. Biosorption using naturally occurring seaweeds can, however, remove contaminants from a variety of sources, including heavy metals, nitrogen, phosphorus, and phenolic compounds, and dyes from the paper, textile, and printing industries. Biosorption utilizing seaweed has surfaces as a feasible substitute for existing technologies in the effective elimination of these pollutants from effluent on account of its environmentally sustainable nature, readily available resources, and cost-effectiveness. An economical adsorbent known as seaweed is examined in this article in order to remove contaminants from effluent. In an extensive table, the application of seaweed in effluent treatment is detailed. The majority of studies, according to published research, have utilized simulated wastewater; biosorption using seaweed to remediate actual wastewater has received less attention.

(Invited) Evaluating Urban Water-Energy Systems Based on UN Sustainable Development Goals (SDGs)

Evaluating Urban Water-Energy Systems Based on UN Sustainable Development Goals (SDGs) Water, food, and energy are three of the major resource issues facing the world today. To help address these issues, urban wastewater is now being considered as a renewable resource than as a waste- a resource for water, for energy, and fertilizers. It is now well recognized that the traditional urban wastewater infrastructure needs to be re-engineered for improved environmental, social, and economic sustainability by minimizing the energy input for treating the wastewaters and by recovering water, energy, and fertilizers from the wastewater for beneficial reuse. In recent years, several alternate technologies have been proposed to take advantage of the water-energy nexus in urban wastewater infrastructure systems. This paper presents a case study evaluating sustainability of four urban water-energy nexus based on the 17 United Nations Sustainable Development Goals (SDGs) that have been unanimously endorsed by all 193 member countries. A multi-criteria decision making (MCDM) approach is used in this study to evaluate the four alternate urban water-energy systems in terms of 30 criteria spanning environmental, social, and economic sustainability. The 30 criteria selected here were derived from the 17 SDGs. The MCDM approach was selected in this study because of its ability to handle quantitative and qualitative criteria and rank the options on a numerical scale. The four wastewater treatment alternatives were evaluated under 12 different scenarios considering high/low priorities of decision-makers towards six different water-energy nexus attributes (pathogen removal, energy consumption, gaseous emission, resource recovery, footprint, and past records).

Photosynthetic Bacteria as an Alternative Wastewater Treatment in Freshwater Aquarium Fish Set Up

Waste produced from aquaculture ultimately hampered the water quality and growth performance of species cultured. Therefore, the potential exploitation of photosynthetic bacteria (PSB) from aquaculture waste was investigated to treat the wastewater in the fish culture. In this study, the wastewater was collected from a fishpond and cultured in sunlight-exposed sterile bottles for 14 days. In the water additive experiment, five treatments (in a 30 cm3 aquarium) were prepared namely cultured PSB (T1), aquatic plant hornwort (T2), aquatic plant salvinia (T3), positive control (P), and negative control (N). Five individuals of Hyphessobrycon herbertaxelrodi (2.5±0.5 cm length) were placed in each treatment and reared for 30 days. Meanwhile, for the wastewater treatment, four treatments (in a 30 cm3 aquarium) were prepared namely wastewater from the hatchery fishpond (S1), wastewater from the hatchery fish tank (S2), positive control (P), and negative control (N). The results obtained indicate that T1 treatment significantly improved and maintained the water quality as compared to other treatments. The results showed the amount of ammonia and nitrite in S1 and S2 supplied with T1 for 30 days gradually decreased from day 1 until day 18. While zero amount of ammonia and nitrate was acquired from day 21 until day 30 of the wastewater experiment. The treatment with PSB showcased the bacteria's ability to utilize and absorb nutrients, thereby maintaining and improving water quality. The potential use of beneficial bacteria in the culture system can accelerate the nitrogen cycle for a sustainable way of wastewater management.

A multi-criteria decision framework for circular wastewater systems in emerging megacities of the Global South

Lima faces increasing water stress due to demographic growth, climate change and outdated water management infrastructure. Moreover, its highly centralized wastewater management system is currently unable to recover water or other resources. Hence, the primary aim of this study is to identify suitable wastewater treatment alternatives for both eutrophication mitigation and indirect potable reuse (IPR). For eutrophication mitigation, we examined MLE, Bardenpho, Step-feed, HF-MBR, and FS-MBR. For IPR, we considered secondary treatment+UF + RO + AOP or MBR + RO + AOP. These alternatives form part of a WWTP network at a district level, aiding Lima's pursuit of a circular economy approach. This perspective allows reducing environmental impacts through resource recovery, making the system more resilient to disasters and future water shortages. The methods used to assess these scenarios were Life Cycle Assessment for the environmental dimension; Life Cycle Costing for the economic perspective; and Multi-Criteria Decision Analysis to integrate both the quantitative tools aforementioned and qualitative criteria for social and techno-operational dimensions, which combined, strengthen the decision-making process. The decision-making steered towards Bardenpho for eutrophication abatement when environmental and economic criteria were prioritized or when the four criteria were equally weighted, while HF-MBR was the preferred option when techno-operational and social aspects were emphasized. In this scenario, global warming (GW) impacts ranged from 0.23 to 0.27 kg CO2eq, eutrophication mitigation varied from 6.44 to 7.29 g PO4− equivalent, and costs ranged between 0.12 and 0.17 €/m3. Conversely, HF-MBR + RO + AOP showed the best performance when IPR was sought from the outset. In the IPR scenario, GW impacts were significantly higher, at 0.46–0.51 kg CO2eq, eutrophication abatement was above 98 % and costs increased to ca. 0.44 €/m3.

Phytoremediation: A Shift Towards Sustainability for Dairy Wastewater Treatment

AbstractDairy processing industries have emerged as the most swiftly evolving sectors with excessive wastewater generation containing proteins, fat, oils, greases (FOGs), etc. As there is rising strain on energy usage and dependence on water resources, sustainable research focuses on reduction in wastewater generation and developing value‐added goods. An effective and widely explored sustainable technique for treating wastewater is phytoremediation, a plant‐based process. This review aims to analyze phytoremediation as a sustainable alternative for dairy wastewater treatment. It initially briefs about dairy wastewater characteristics and treatment alternatives and discusses constructed wetlands and hydroponic system in detail with mechanism insights and influenced process parameters. Interconnected technologies with phytoremediation and their impact on contaminant transformations, nutrient reuse, and detoxification of pollutants are encompassed. Also, resource recovery and biomass utilization, feedstock enrichment along with the future prospects of integrated hydroponic systems for achieving sustainability with efficient resource recovery are featured.

Synthesis of Bamboo-based Activated Carbon through Physico-chemical Activation for Coal-runoff Wastewater Treatment

Bamboo-based activated carbon (BAC) has been successfully synthesized through a physico-chemical technique. The characteristics of BAC were investigated using Scanning Electron Microscopy (SEM), Fourier Transform Infra-Red (FTIR), and X-Ray Diffraction (XRD). Evaluating BAC performance on coal-runoff wastewater was carried out by varying contact times and adding low-level alum on remediation of pH and Total Suspended Solid (TSS). The results confirm that BAC performs well in stabilizing pH, indicated by the neutral pH, after 10 minutes of interaction. The TSS with BAC treatment and 1% BAC-Alum combination reduced the TSS value from 880 mg/L to levels below the threshold for wastewater quality standards, 387 mg/L and 73 mg/L, respectively. This combination can be an alternative coal-runoff wastewater treatment technique for better environmental quality.