P. S. Kamble, Devanshu Kodhey, Rahul A. Bhende et al.

International Journal of Advanced Research in Science Communication and Technology • 2025

Dairy wastewater presents a significant environmental challenge due to its high concentrations of organic matter, nutrients, and suspended solids. Conventional treatment methods, while effective in pollutant removal, often involve energy-intensive processes that generate excess sludge and require substantial operational costs. With the growing demand for sustainable and energy-efficient technologies, integrating constructed wetlands (CWs) with microbial fuel cells (MFCs) emerges as a promising solution. The growing demand for sustainable wastewater treatment technologies has led to the exploration of hybrid systems that combine ecological treatment with energy recovery. Dairy wastewater, characterized by high organic load, nutrients, and suspended solids, presents a significant environmental challenge if discharged untreated. This study investigates an integrated system that combines a constructed wetland (CW) with a microbial fuel cell (MFC) to simultaneously treat dairy wastewater and generate electricity. The constructed wetland acts as a biofilter to reduce pollutants, while the microbial fuel cell harnesses the metabolic activity of electrogenic bacteria to convert organic matter into electrical energy. This study investigates the performance of a hybrid CW-MFC system in simultaneously treating dairy wastewater and generating electricity. The constructed wetland acts as a natural biofilter, facilitating the removal of contaminants through physical, chemical, and biological mechanisms, while the microbial fuel cell component utilizes electrogenic bacteria to oxidize organic matter and convert chemical energy into electrical energy. Experimental analysis was conducted using synthetic and real dairy wastewater under varying operational conditions, including different hydraulic retention times, electrode materials, and plant species.The results demonstrate that the CW-MFC system effectively reduces pollutants such as BOD, COD, and nutrients while generating a measurable amount of electricity. The hybrid system not only enhances wastewater treatment efficiency but also contributes to renewable energy generation. This integrated approach offers a cost-effective, environmentally friendly alternative to conventional wastewater treatment methods, with significant potential for scalability and rural application

Monolina Sarkar

Journal of Hazardous Materials Advances • 2023

The existence of micropollutants in wastewater is one of the most challenging environmental issues in the world today. Due to their high stability and resistance to physicochemical and biological degradation, pollutants like hormonally active substances, pesticides, industrial chemicals, pharmaceuticals, personal care products, doping substances, and narcotics among others are difficult to remove in wastewater treatment plants (WWTPs). A potential technology for treating pollutants is photocatalytic biodegradation. The advancements in light-responsive biodegradation technologies—namely, intimately coupled photocatalysis and biodegradation (ICPB), microbial fuel cells (MFCs), and photobiocatalysis are highlighted in this work. The article identifies opportunities for refining current methodologies. It aims to provide a perspective for future research devoted to assessing and improving pollutant removal.

Marwa M. Jiad, Ali H. Abbar, Zaid H. Jabbar

Environmental Technology Reviews • 2025

Abdollah Dargahi, Reza Shokoohi, Ghorban Asgari et al.

RSC Advances • 2021

Application for real wastewater, kinetics modelling, effect of operating parameters on removal of 2,4-D using MBBR–3DE processes, improvement of biodegradability and Identification of herbicide-degrading microorganisms.

Tope Oyebade, Oluwatoyin Adekoya

GSC Biological and Pharmaceutical Sciences • 2022

Pharmaceutical residues have emerged as persistent micropollutants in aquatic ecosystems, posing ecological, toxicological, and public health challenges due to their bioaccumulation and resistance to conventional wastewater treatment. Advanced oxidation processes (AOPs) have gained prominence for degrading such complex compounds, yet individual techniques often suffer from operational inefficiencies, incomplete mineralization, or high energy demands. This study explores the integration of electrochemical oxidation (EO) and photocatalysis as a synergistic treatment pathway capable of addressing these limitations under variable environmental conditions. The hybrid system combines the anodic generation of reactive oxygen species (•OH, O₂•–) with photoexcited semiconductor catalysts such as TiO₂ or doped ZnO, enabling simultaneous oxidation and photodegradation of pharmaceutical contaminants. The integration enhances electron–hole separation, improves mass transfer, and extends the oxidative potential beyond either process alone. Experimental simulations under varying pH, temperature, and light intensity demonstrate that the combined EO–photocatalytic process achieves higher degradation efficiency and total organic carbon (TOC) removal than standalone systems. Mechanistic analysis reveals that environmental conditions critically influence radical formation kinetics, electrode stability, and catalyst photoreactivity, thereby dictating the overall mineralization rate. Furthermore, the process exhibits resilience against matrix interferences such as chloride, bicarbonate, and natural organic matter. The study concludes that optimized hybrid EO–photocatalytic configurations represent a scalable and sustainable route for removing persistent pharmaceuticals from wastewater, contributing to circular water management and pollution mitigation. Future work should focus on energy recovery, reactor design optimization, and real effluent validation to ensure full-scale applicability in diverse climatic contexts.

Chengzhi Wang, Yi Xing, Kangning Zhang et al.

Journal of Power Sources • 2023

A photocathode-microbial electrochemical coupling system (PC-MFC) using black phosphorus-doped titanium dioxide nanobelt (BP/TB) as a photocatalyst is constructed for the degradation of hydroxychloroquine (HCQ, used to treat COVID-19). The degradation efficiency of HCQ (100 mg/L) in coupling system is 73.7% within 8 h, higher than that of photocatalysis (69.5%), MFC (25.6%), and adsorption (9.6%). The photocathode coupling facilitates subsequent bioelectric treatment, resulting in complete degradation of HCQ (100 mg/L) within 96 h in PC-MFC, much higher than in MFC (51.1%). Illumination of PC-MFC significantly increases the cathodic abundance of Pseudomonadales ord. (from 1.83% to 66.30%), accumulates biomass, improves the electrochemical behaviors of photocathode and bioanode, and finally increases the maximum power from 241 to 280 mW/m 2 . The electron transfer pathways depende on nicotinamide adenine dinucleotide dehydrogenase , succinate dehydrogenase and terminal oxidase . The coupled system enhances the dechlorination reduction of HCQ and reduces the biotoxicity of its degradation pathway. PC-MFC represents a new strategy for the treatment and energy recovery of refractory organic compounds in wastewater. • A single-chamber microbial fuel cell with a coupled photocathode was constructed. • The system increased the removal of hydroxychloroquine (HCQ) by 52.0%. • The system facilitated electrochemical behaviors and electricity production. • Photocathode increased the abundance of Pseudomonadales ord. and enriched biomass. • The photocathode enhanced the dechlorination and reduced the toxicity of HCQ.

Nuno Jorge, Ana R. Teixeira, Marco S. Lucas et al.

Environmental Research • 2025

Xinying Zhang, Yan Wu, Gao Xiao et al.

PLoS ONE • 2017

Azo dyes are very resistant to light-induced fading and biodegradation. Existing advanced oxidative pre-treatment methods based on the generation of non-selective radicals cannot efficiently remove these dyes from wastewater streams, and post-treatment oxidative dye removal is problematic because it may leave many byproducts with unknown toxicity profiles in the outgoing water, or cause expensive complete mineralization. These problems could potentially be overcome by combining photocatalysis and biodegradation. A novel visible-light-responsive hybrid dye removal agent featuring both photocatalysts (g-C3N4-P25) and photosynthetic bacteria encapsulated in calcium alginate beads was prepared by self-assembly. This system achieved a removal efficiency of 94% for the dye reactive brilliant red X-3b and also reduced the COD of synthetic wastewater samples by 84.7%, successfully decolorized synthetic dye-contaminated wastewater and reduced its COD, demonstrating the advantages of combining photocatalysis and biocatalysis for wastewater purification. The composite apparently degrades X-3b by initially converting the dye into aniline and phenol derivatives whose aryl moieties are then attacked by free radicals to form alkyl derivatives, preventing the accumulation of aromatic hydrocarbons that might suppress microbial activity. These alkyl intermediates are finally degraded by the photosynthetic bacteria.

Chun Zhao, Weijie Yang, Qianyong Zhang et al.

Frontiers in Science and Engineering • 2025

This study addresses the problems of high energy consumption, high cost, and incomplete removal existing in traditional treatment methods for oily wastewater from ships, and proposes and constructs a Photocatalytically-assisted Microbial Fuel Cells (PMFC) device for efficient and green treatment. The device couples photocatalysis with Microbial Fuel Cell (MFC) technology, utilizing ⋅OH and ⋅O2− generated by semiconductor photocatalysts under illumination to synergistically degrade oil pollutants with microbial metabolism. Specifically, pine cone shell biochar (PBC) modified by high-temperature carbonization (350°C) and H₂O₂ oxidation (HPBC) is used as the anode substrate, which significantly improves its hydrophilicity (contact angle reduced to 44.637°) to facilitate the attachment of photocatalysts and microorganisms. Then, a TiO₂/g-C₃N₄ heterojunction photocatalyst (TiO₂/g-C₃N₄@HPBC) is loaded to construct a composite photoanode. A two-chamber PMFC reactor is built, using an emulsified diesel solution prepared with an inorganic salt medium as the anolyte, a potassium ferricyanide solution as the catholyte, and a composite microbial community as the anode microorganisms. The results show that the maximum output voltage of 0.6389V and oil degradation rate of 76.34% of PMFC under illumination are significantly higher than the maximum output voltage of 0.5832V and oil degradation rate of 71.72% under dark conditions, confirming that the photocatalytic effect effectively improves the power generation performance and pollutant degradation efficiency of the system. The PMFC device provides an energy-saving and efficient potential solution for the treatment of oily wastewater from ships.

Rajanandini Meher, M. Matheshwaran, Naresh Kumar Sharma

Environmental Technology • 2025

The growing demand for surgical cotton in the healthcare sector has led to increased production in southern Tamil Nadu, generating effluents that pose environmental risks due to their chemical composition. Unlike conventional textile effluents, surgical cotton processing wastewater is distinct for its lack of colour additive, but it exhibits high chemical oxygen demand (COD) and contains significant inorganic pollutants, necessitating tailored treatment strategies. Despite extensive research on textile wastewater, effective solutions for surgical cotton effluents remain underexplored. This research bridges this gap by exploring a novel synergic method, algae-bacterial symbiosis combined with photocatalytic degradation for real surgical cotton effluent, in order to ultimately improve the removal ability of the contaminants. The general aim was to study the performance of three continuous reactor, a photocatalytic reactor, a biological rector and coupled biological-photocatalytic (CBPCR) reactor in the degradation of surgical cotton processing effluent during 30 days. The treatment efficacy was measured by observing the removal rates of inorganic nutrient, COD, and microbial growth. It was concluded that the CBPCR system successfully removed nitrate, phosphate, ammonia, and COD by 90%, 87%, 75%, and 93% respectively. In particular, the system fostered vigorous growth of both microalgae and bacteria, as indicated by a total chlorophyll concentration of 20.1 ± 0.91 mg/L and a dry cell weight of 1.81 ± 0.09 g/L. This paper shows the feasibility of the CBPCR system as a green, sustainable strategy for the treatment of surgical cotton effluent and as such fills a gap in current practice of industrial wastewater treatment.

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