Kitchen Wastewater Research Articles

Improved kitchen wastewater treatment using PbO2-coated graphite electrode

This study investigates the electrochemical treatment of kitchen wastewater (KW) using a PbO₂-coated graphite (G-PbO₂) electrode prepared via ultrasound-assisted electrochemical deposition. The G-PbO2 electrode was characterised through various techniques, including X-ray diffraction analysis (XRD), X-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM), confirming the successful deposition of PbO₂ and enhanced catalytic activity. Under optimal conditions (current density 0.75 Adm−2, electrolyte concentration 1.5 gL-1, electrode distance 2 cm, and pH 3), the G-PbO₂ electrode achieved a 94 % COD reduction with an energy consumption of 0.002 kWh gCOD−1. These results highlight the superior performance of the electrode in COD removal, accompanied by low energy consumption.

E-Waste-Derived Electrode for Electrooxidation of Kitchen Wastewater

E-Waste-Derived Electrode for Electrooxidation of Kitchen Wastewater

Comparison of anaerobic co-digestion of vacuum toilet blackwater and kitchen waste under mesophilic and thermophilic conditions: Reactor performance, microbial response and metabolic pathway

Co-digestion of kitchen waste (KW) and black water (BW) can be considered as an attractive method to efficiently achieve the clean energy from waste. To find the optimal operation parameters for the co-digestion, the effects of different temperatures (35 and 55 °C) and BW:KW ratios on the reactor performances, microbial communities and metabolic pathways were studied. The results showed that the optimum BW:KW ratio was 1:3.6 and 1:4.5 for mesophilic and thermophilic optimal reactors, with methane production of 449.04 mL/g VS and 411.90 mL/g VS, respectively. Microbial communities showed significant differences between the reactors under different temperatures. For bacteria, increasing BW:KW ratio significantly promoted Defluviitoga enrichment (1.1%–9.5%) under thermophilic condition. For Archaea, the increase in BW:KW ratio promoted the enrichment of Methanosaeta (8.6%–56.4%) in the mesophilic reactor and Methanothermobacter (62.0%–89.2%) in the thermophilic reactor. The analysis of the key enzymes showed that, acetoclastic methanogenic pathway performed as the dominant under mesophilic condition, with high abundance of Acetate-CoA ligase (EC:6.2.1.1) and Pyruvate synthase (EC:1.2.7.1). Hydrogenotrophic methanogenic pathway was the main pathway in the thermophilic reactors, with high abundance of Formylmethanofuran dehydrogenase (EC:1.2.99.5).

Sustainable kitchen wastewater treatment with electricity generation using upflow biofilter-microbial fuel cell system.

The microbial fuel cell (MFC) is considered a modern technology used for treating wastewater and recovering electrical energy. In this study, a new dual technology combining MFC and a specialized biofilter was used. The anodic materials in the system were crushed graphite, either without coating (UFB-MFC) or coated with nanomaterials (nano-UFB-MFC). This biofilter served as a barrier to retain and remove turbidity and suspended solids, while also facilitating the role of bacteria in the removal of organic pollutants, phosphates, nitrates, sulfates, oil and greases. The results demonstrated that both systems exhibited high efficiency in treating kitchen wastewater, specifically greywater and dishwashing wastewater with high detergent concentrations. The removal efficiencies of COD, oil and grease, suspended solids, turbidity, nitrates, sulfates, and phosphates in first UFB-MFC were found to be 88, 95, 89, 86, 87, 75, and 94%, respectively, and in Nano-UFB-MFC were 86, 99, 95, 91, 81, 88, and 95%, respectively, with a high efficiency in recovering bioenergy reaching a value of 1.8 and 1.5Am-3, respectively. The results of this study demonstrate the potential for developing MFC and utilizing it as a domestic system to mitigate pollution risks before discharging wastewater into the sewer network.

Removal of Oil and Grease from Oily Kitchen Wastewater by Using Raw Kapok as a Potential Adsorbent

Oil and grease are one of the elements that are poisonous and easily pollute the environment, especially water and soil. Adsorption techniques use natural adsorbents that do not damage or pollute the environment. The raw kapok was chosen as an adsorbent because it is a technology to overcome the problem of oil produced globally. The experiment was conducted with two types of dosage which are 5g and 15g of raw kapok to absorb the oil and the results stated that raw kapok can absorb the cooking oil that is still not used more than the cooking oil that has been used. Due to the density of the oils, it affects the ability of raw kapok to absorb and hold oil. In addition, this absorbed oil restores several water parameters such as dissolved oxygen (DO), pH, temperature and turbidity.

Effective anaerobic digestion performance from kitchen wastewater by nanoscale zero-valent iron composite materials: Hydrogen corrosion capability and biological biogas upgrading

In this study, nanoscale zero-valent iron (nZVI) was modified by carboxymethylcellulose (CMC), extracellular polymeric substances (EPS) and sodium dodecyl sulfate (SDS), which were compared for the ability of hydrogen corrosion and then for the biogas upgrading during kitchen wastewater anaerobic digestion. The results showed that three nZVI composite materials addition could increase hydrogen evolution performance by 6.11∼10.30 % compared with nZVI. Especially, the hydrogen evolution from sodium dodecyl sulfate modified composite material reached 121.0 mL/g. The continuous release of hydrogen promoted the biogas yield to 510.96 mL/gVS in reaction group with SDS12-nZVI10 addition (N4), with CH4 content reached 93.37 %. Microbial community analysis showed that the total relative abundance of Methanothrix and Methanolinea was 43.60 % in N4, which was higher than other groups. It was indicated that H2-assisted biogas upgrading with nZVI composite materials addition was achievable, particularly in N4.

Fulvic acid-mediated efficient anaerobic digestion for kitchen wastewater: Electrochemical and biochemical mechanisms

Fulvic acid, prevalent in humus derived from the anaerobic digestion of kitchen wastewater, is crucial in organic matter transformation. However, its effects and underlying mechanisms remain unclear. In this study, the fate of anaerobic digestion of artificial and kitchen wastewater with different fulvic acid contents was investigated. The results showed that 125 mg/L fulvic acid resulted in a 64.02 and 51.72 % increase in methane production in synthetic and kitchen wastewater, respectively. Fulvic acid acted as an electron mediator and increased substrate oxidation by boosting NAD and ATP levels, thereby increasing microbial metabolic rates and ensuring an adequate substrate for methane generation. Isotope analysis suggested that fulvic acid boosts the conversion of volatile fatty acids to methane via the interspecies electron transfer pathway. Gene expression analysis revealed that cytochrome c, FAD, and other electron transport coenzymes were upregulated by fulvic acid, thereby enhancing substrate utilisation and biogas quality. Fulvic acid presented a dual stimulatory and inhibitory effect on anaerobic digestion, with concentrations over 125 mg/L diminishing its positive impact. This dual effect may stem from the properties and concentrations of fulvic acid. This study revealed the effect mechanism of fulvic acid and provided insights into the humus performance in anaerobic digestion

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.

Effects of dilution and pretreatment on nutrient removal and biomass production of Chlorella vulgaris in kitchen wastewater

This research investigated the effect of kitchen wastewater (KWW) concentrations and pretreatment methods on Chlorella vulgaris biomass production, lipid content and nutrient removal. This study was divided into two separate experiments. The first experiment determined the appropriate dilution rate of KWW for the growth of microalgae, sterilized KWW was varied between 25%, 50%, 75%, and 100%(v/v). The result indicated that 50%(v/v) showed the highest nutrient removal by 90.23%, 85.87%, and 80.64% of sCOD, TKN, and TP, respectively. The highest biomass and lipid content were obtained with 50%(v/v) (1.447 g/L, 37.9%). The second experiment was to find an effective physical pretreatment method, which separated the biotic contaminant, non-sterilized KWW was diluted 50%(v/v) and filtered with different mesh size filters (150 μm, 50 μm, and 30 μm) compared with sterilized KWW as a control sample. The result indicated that pretreatment with 50 μm filtration was found highest nutrient removal by 90.51%, 84.74%, and 77.50% of sCOD, TKN, and TP, respectively. The highest biomass and lipid content were obtained with 50 μm filtration (1.496 g/L, 39.4%). Our results support the hypothesis that the optimal dilution and proper filtration of KWW helps create more favorable environment for microalgal growth.

Microbial-Based Treatment of Kitchen Waste and Kitchen Wastewater: State-of-the-Art Progress and Emerging Research Prospects Related to Microalgae and Bacteria

Microbial-Based Treatment of Kitchen Waste and Kitchen Wastewater: State-of-the-Art Progress and Emerging Research Prospects Related to Microalgae and Bacteria

Photocatalysis of low-density polyethylene using FKMW-ZnO NPs: optimization and predication model using a radial basis function neural network ensemble system

The present study aimed to investigate the efficiency of biosynthesized zinc oxide nanoparticles in fungal supernatant grown in kitchen wastewater with microelectronic sludge (FKMW-ZnO NPs) to be used in the degradation low-density polyethylene (LDPE) in aqueous solution. The photocatalysis process was optimized using response surface methodology as a function of four independent factors included LDPE concentrations x1\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\left( {x_{1} } \\right)$$\\end{document} (100–500 mg/100 mL), FKMW-ZnO NPs concentrations x2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\left( {x_{2} } \\right)$$\\end{document} (10–100 mg/100 mL), time x3\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\left( {x_{3} } \\right)$$\\end{document} (1–6 h) and pH x4\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\left( {x_{4} } \\right)$$\\end{document} (4–9). The maximum photocatalysis of LDPE was 45.43% optimized with 229.96 mg LDPE/100 mL, 100 mg FKMW-ZnO NPs/100 mL at pH 7 and after one hour with R2 is 0.7377. Microstructure and chemical structure analysis showed a significant change in the chemical structure of the photocatalysis of LDPE because of FKMW-ZnO NPs. The mathematical predication model using a radial basis function neural network ensemble system (RBFNNES) provided more accurate prediction model 89.2857% with R2 = 0.8688. However, RBFNNES revealed that FKMW-ZnO NPs and LDPE have unstable behaviour towards the investigated factor and the interaction between these factors where the error was increasing with the increasing the time of neural network which indicates that the obtained efficiency in the optimization study might be not applicable in the large scales or in different environmental factors. More optimization with a wide range of factors is required to understand the applicability of FKMW-ZnO NPs in remediation of LDPE in the environment.Graphical

Experimental study of treatment of kitchen waste water using rice husk ash

Kitchen wastewater is nutrient and carbon-rich, and if properly collected and treated, it may provide new water, fertilizer, and energy. The important contaminants in domestic wastewater from the kitchen include organic load from food processing, utensil cleaning in the kitchen, soap, and detergents, these are oil and grease, proteins, carbohydrates, and other dissolved and suspended substances. These particles can also be removed effectively and the treated water used for agriculture or gardening. Kitchen wastewater treatment involves determination of Biochemical Oxygen Demand(BOD), Chemical Oxygen demand(COD),Total suspended solid(TSS). Numerous techniques are employed globally to handle kitchen waste. The removal of various pollutants from wastewater and wastewaters is now being explored using rice husk, a material that is both ubiquitous and relatively inexpensive. The present work deals with the practicability of applying continuous process for removal of BOD, COD, and TSS, using Rice husk ash as adsorbent. In present study continuous process is adopted to check the viability of rice husk as adsorbent. The effects of operating parameters on BOD, COD, TSS removal were studied. From the experiment the optimum conditions were determined as 15 cm depth of Rice husk ash(RHA) layer and 60 min detention time. At the optimum conditions, removal efficiencies for Chemical Oxygen Demand (94%), Biochemical Oxygen Demand(90%), Total Suspended Solids(91%) were observed. It is observed that Rice Husk(RH) can be used as effective adsorbent for treatment of kitchen wastewater.

Development of an alternative low-cost culture medium for a new isolated high-production DHA strain using kitchen wastewater

Docosahexaenoic acid (DHA) is a high-value polyunsaturated fatty acid. The industrial development of microbial DHA was restricted due to high medium cost. Kitchen wastewater was always rich in nitrogen, phosphorous, carbohydrates, which can be used for microorganism growth. This study developed of a primitive low-cost culture medium for a new isolated high-production DHA strain using kitchen wastewater. The results showed that, a total of 66 strains were isolated from mangrove habitats. The highest DHA-producing strain N6 was identified as Aurantiochytrium sp. (GenBank accession number OL455742) with a DHA production of 6.56 g/L. Then the optimization of kitchen wastewater medium was designed by Response Surface Methodology, and 7.14 ∼ 7.23 g/L of DHA production was obtained. At the same time, the lipid content in Aurantiochytrium sp. N6 was as high as 75.68%, which contributed to the increase of DHA production in optimal kitchen wastewater medium. Finally, the substrate cost of kitchen wastewater medium was reduced by 43.95%. Meanwhile, the dissolved organic carbon (DOC), dissolved nitrogen (DN) and dissolved phosphorus (DP) in kitchen wastewater were utilized by Aurantiochytrium sp. N6 more than 90%. This work enriched the competitive candidate DHA-producing microbes, and provided a perceptive idea for both the medium substrate cost reducing and kitchen wastewater recycling.

Extrusion of Silicon Carbide Based Tubular Membrane Incorporated With Coal Fly Ash and Performance Evaluation in Water Treatment

Development of an efficient membrane from waste resources has been receiving growing interest. The utilization of industrial waste coal fly ash (CFA) for the preparation of SiC based tubular membrane has reduced the raw material cost and sintering temperature, and hence beneficial in both economic and environmental points. In the present work, tubular membrane was prepared by extrusion of ceramic paste formulated using SiC powder, CFA, suitable dispersant, plasticizer and additives. The extruded green body was dried and then sintered at 850°C. The membrane was characterized by measuring porosity, morphology by scanning electron microscopy, linear shrinkage, mechanical strength. The membrane performance was evaluated using synthetically prepared oil-water emulsion, turbid water, kitchen wastewater and industrial wastewater. The membrane was found to remove 93-95% of oil depending on the oil concentration in the feed water. The oil rejection potential of the membrane was compared with other membranes reported in the literature and the results indicated that the membrane prepared in this study had a strong potential applications in wastewater treatment.

Microporous nitrogen-rich biomass derived anode catalyst in clay membrane MFC for kitchen wastewater treatment

ABSTRACT Microbial fuel cells (MFC) have emerged as a sustainable wastewater treatment technique that offers simultaneous energy generation; however, the high cost of electrodes and their reduced catalytic activity have hindered their widespread adoption. To overcome this, an activated carbon synthesised from Areca nut husk was coated on different anodes viz. Carbon cloth and Stainless Steel (SS) mesh. Activated carbon was found to be highly porous with a carbon content of 85.39%, and a surface area of 767.98 m2/g, and was found to be amorphous with a high degree of graphitic structure. The electrical conductivities of the catalyst-coated SS mesh and carbon cloth were comparable, and the performance of the MFC was studied using both electrodes as anodes. A batch MFC with modified SS mesh as anode exhibited the highest power density of 155.35 mW/m3 in synthetic wastewater and 101.68 mW/m3 in kitchen wastewater, with COD removal efficiencies of 95.32% and 95.24%, respectively. In a continuous mode, the MFC delivered a maximum current density and power of 52.38 mA/m2 and 21.60 mW, respectively, with a maximum COD removal efficiency of 80.70% for an HRT of 20 hrs. These findings underscore the viability of using biomass-derived activated carbon as an anode catalyst in both batch and continuous modes of MFC.

Oil–water separation in kitchen wastewater filtration using milkweed floss fiber

Oil–water separation in kitchen wastewater filtration using milkweed floss fiber

Establishment and optimization of sulfur-based autotrophic-heterotrophic denitrification biofilters for advanced post-anaerobic treatment of effluent from kitchen wastewater and landfill leachate under low temperature

Landfill leachate treatment is a major challenge in wastewater treatment. In this study, two sulfur-based autotrophic-heterotrophic denitrification biofilters (Ra biofilter with room-temperature molded filler and Rb biofilter with melt molded filler) were used to treat kitchen-landfill leachate at low temperatures. The effects of reflux ratio, concentrations of NaHCO3, and Na2S2O3 on the total nitrogen removal efficiency were analyzed, and based on response surface methodology, the optimum parameters were determined. After optimization, the total nitrogen removal efficiency for the Ra and Rb biofilters increased by 83% and 81%, respectively. Moreover, sulfur-based autotrophic denitrification accounted for more than 70% of the nitrogen removal in both biofilters. Based on high-throughput sequencing results, the functional bacteria exhibited high abundance in the Ra biofilter, indicating that the room-temperature molded filler favored the enrichment of functional bacteria. These findings were important for optimizing the operation of sulfur autotrophic-heterotrophic denitrification biofilters at low temperatures.

Degradation and power generation performance of modified-anode microbial fuel cells for kitchen wastewater

Microbial fuel cells (MFCs) are innovative devices that simultaneously generate electricity and treat wastewater. The performance of MFCs heavily relies on the anode, which serves as the site for the enrichment, electron generation, and transfer of electricity-producing microorganisms. In this study, Researcher investigated the impact of modified electrode materials (Fe3N-Fe3C/CF) loaded with iron nitride and iron carbide nanoparticles at different temperatures on MFC performance, employing carbon felts as anodes. Our results reveal a significant enhancement in the electrical performance of the modified carbon felt anode compared to conventional carbon felt. Notably, when the modified electrode was prepared at 850 °C, the output voltage of the microbial fuel cell assembled with the modified electrode was significantly increased, and its maximum power density increased from 28.57 MW m−2 to 58.86 MW m−2. These findings highlight the potential of high-performance anode materials, as demonstrated in this study, to serve as a reference for enhancing MFC performance.

Design and Long-Term Performance of a Pilot Wastewater Heat Recovery System in a Commercial Kitchen in the Tourism Sector

This paper assesses the performance of waste heat recovery from commercial kitchen wastewater in practice. A pilot study of heat recovery from the kitchen at Penrhyn Castle, a tourist attraction in North Wales (UK), is outlined. The pilot heat recovery site was designed and installed, comprising a heat exchanger, recirculation pumps, buffer tank and an extensive temperature/flow monitoring system for performance monitoring of the waste heat recovery system. Continuous monitoring was conducted for a period of 8 months, covering the 2022 tourist season. The recovered heat from the kitchen wastewater preheats the incoming cold freshwater supply and consequently reduces the amount of energy consumed for subsequent water heating. Retrofitting the pilot heat recovery system to the kitchen drains resulted in a heat saving of 240 kWh per month on average, a reduction of 928.8 kg CO2e per year, and a payback period for the investment costs of approximately two years, depending on the cost of energy supply. The presented results illustrate the potential of this form of renewable heat in reducing the carbon footprint of water heating activities in buildings and the hospitality sector.

Intensified treatment of kitchen wastewater in a filter- press type electrochemical reactor

Commercial kitchen wastewater (KW), characterized by a high load of bio-refractory organics, can be effectively treated by electrochemical methods for non-potable applications. This work explores the electrochemical degradation of KW in a batch recirculation type flow reactor consisting of mixed metal oxides coated titanium mesh anode and stainless steel cathode. The effect of operating factors such as current density, supporting electrolyte concentration, initial pH, and recirculation flow rate on chemical oxygen demand (COD) reduction was examined by following one-factor-at-a-time method. The %COD reduction increased with an increase in electrolyte concentration and current density. The optimum current density and electrolyte concentration were found to be 2 A/dm2 and 2 g/L, respectively. The treatment was intensified by incorporating mechanical stirring and ultrasound irradiation in the reservoir. The results showed about 99 % COD reduction, and the kinetic model proposed predicted the experimental data satisfactorily.