356,595 research outputs found

    A review on the present situation of wastewater treatment in textile industry with membrane bioreactor and moving bed biofilm reactor

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    Membrane bioreactor (MBR) is one of the advanced treatment technologies used in industrial wastewater treatment due to its various advantages over conventional biological processes. Recently, the application of MBR in treatment of textile wastewater has increased significantly with an effective removal of contaminants. Moving bed bioreactor (MBBR) has been efficiently used for the treatment of different municipal and industrial wastewater during the last decades and it is a relatively novel and effective technology applied in textile wastewater treatment. This review paper presents the situation of MBR and MBBR technology for textile wastewater purification under different conditions and collates results of previous studies during the past years about MBR and MBBR treatment technologies used in textile processes. Both of these two technologies have shown their efficiency, but they still have problems in textile wastewater treatment. To this end, MBR-MBBR hybrid system could be an attractive solution for textile wastewater purification because of the high efficiency and low consumption of energy and spacePostprint (author's final draft

    Temperature, inocula and substrate: contrasting electroactive consortia, diversity and performance in microbial fuel cells

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    The factors that affect microbial community assembly and its effects on the performance of bioelectrochemical systems are poorly understood. Sixteen microbial fuel cell (MFC) reactors were set up to test the importance of inoculum, temperature and substrate: Arctic soil versus wastewater as inoculum; warm (26.5°C) versus cold (7.5°C) temperature; and acetate versus wastewater as substrate. Substrate was the dominant factor in determining performance and diversity: unexpectedly the simple electrogenic substrate delivered a higher diversity than a complex wastewater. Furthermore, in acetate fed reactors, diversity did not correlate with performance, yet in wastewater fed ones it did, with greater diversity sustaining higher power densities and coulombic efficiencies. Temperature had only a minor effect on power density, (Q10: 2 and 1.2 for acetate and wastewater respectively): this is surprising given the well-known temperature sensitivity of anaerobic bioreactors. Reactors were able to operate at low temperature with real wastewater without the need for specialised inocula; it is speculated that MFC biofilms may have a self-heating effect. Importantly, the warm acetate fed reactors in this study did not act as direct model for cold wastewater fed systems. Application of this technology will encompass use of real wastewater at ambient temperatures

    Kinetic investigation and optimization of a sequencing batch reactor for the treatment of textile wastewater

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    Discharging of untreated or partially treated textile wastewater is common in Ethiopia, and this has detrimental effect to the environment. It is difficult to treat textile wastewater by conventional biological processes. In this study, real textile wastewater was taken and treated using sequencing batch reactor using a biomass taken from domestic wastewater treatment plant. Cycle period, air flowrate and sludge retention time (SRT) were initially optimized using the response surface methodology. The optimum ratio of cycle period/air flowrate/SRT which gives a 57% COD removal and 54% color removal was found to be 25 h/15 L/h/16 day. Using two types of wastewater substrate concentrations and various hydraulic retention times at optimized condition, COD removal, color removal, sludge volume index (SVI) and mixed liquor suspended solid were measured. The maximum of COD removal (73%) and color removal (65.8%) was obtained at an organic loading rate of 0.078 kg COD/m3 day. SVI at the optimized condition was found to be 90–92 mL/g. Finally, a first-order kinetic model was used to represent the degradation of textile wastewater

    Renovation of Nitrogenous Wastewater Via Land Application

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    Removal of inorganic and organic nitrogen from wastewater prior to recharge of ground and surface waters can be accomplished by judicious land application. This study focused attention upon the feasibility of using sprinkler irrigation as the wastewater delivery system with coastal bermudagrass (Cynodon dactylon L.,var. coastal) pasture as the wastewater sink. One site was located on a Sawyer soil near El Dorado, while the other was located on a Savannah soil near Malvern. This report is limited to the renovation of surface waters. Results revealed that nitrogen concentration in runoff water from rainfall was substantially less than nitrogen concentration of the wastewater applied to the soil and similar to background levels. Such results support the consideration of land application as a viable wastewater disposal method

    Influent Wastewater Microbiota and Temperature Influence Anaerobic Membrane Bioreactor Microbial Community

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    Sustainable municipal wastewater recovery scenarios highlight benefits of anaerobic membrane bioreactors (AnMBRs). However, influences of continuous seeding by influent wastewater and temperature on attached-growth AnMBRs are not well understood. In this study, four bench-scale AnMBR operated at 10 and 25 °C were fed synthetic (SPE) and then real (PE) primary effluent municipal wastewater. Illumina sequencing revealed different bacterial communities in each AnMBR in response to temperature and bioreactor configuration, whereas differences were not observed in archaeal communities. Activity assays revealed hydrogenotrophic methanogenesis was the dominant methanogenic pathway at 10 °C. The significant relative abundance of Methanosaeta at 10 °C concomitant with low acetoclastic methanogenic activity may indicate possible Methanosaeta-Geobacter direct interspecies electron transfer. When AnMBR feed was changed to PE, continual seeding with wastewater microbiota caused AnMBR microbial communities to shift, becoming more similar to PE microbiota. Therefore, influent wastewater microbiota, temperature and reactor configuration influenced the AnMBR microbial community

    Potential of duckweed for swine wastewater nutrient removal and biomass valorisation through anaerobic co-digestion

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    Over the last decades, phytodepuration has been considered an efficient technology to treat wastewaters. The present study reports a bench scale depuration assay of swine wastewater using Lemna minor. The highest observed growth rate obtained in swine wastewater was 3.1 ± 0.3 gDW m−2 day−1 and the highest nitrogen and phosphorus uptake were 140 mg N m−2 day−1 and 3.47 mg P m−2 day−1, respectively. The chemical oxygen demand removal efficiency in the swine wastewater assay was 58.9 ± 2.0%. Furthermore, the biomass valorisation by anaerobic co-digestion with swine wastewater was assessed. Results showed a clear improvement in specific methane production rate (around 40%) when compared to mono-substrate anaerobic digestion. The highest methane specific production, 131.0 ± 0.8 mL CH4 g−1 chemical oxygen demand, was obtained with a mixture containing 100 g of duckweed per liter of pre-treated swine wastewater. The water-nutrients-energy nexus approach showed to be promising for swine waste management.info:eu-repo/semantics/publishedVersio

    The effect of silane treatment on nanosized carica papaya seed modified pullulan as biocoagulant in wastewater treatment

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    Currently, conventional wastewater treatment process used chemical coagulant such as Aluminium sulphate. However, the residual aluminium in treated wastewater causes toxicity and serious health issues such as Alzheimer’ disease. Thus, in this study the potential of nanosized Carica Papaya (CP) seeds treated by silane coupling agent incorporated to pullulan on wastewater treatment was investigated. The biocoagulant produce prepared at a different composition of CP range from 1% to 9% was used to treat sewage wastewater. The biocoagulant was characterized by particle size analyser, FTIR and FESEM. The treated wastewater was analyzed by jar test in term of turbidity, pH, dissolved oxygen and Total Suspended Solid with biocoagulant dosage at 0.6 g/L. The size of nanosized biocoagulant was obtained at 608.9 nm. Silane treatment provides well dispersion of nanosized Carica Papaya seed powder in the pullulan matrix phase. FTIR analysis shows the presence of O-H, C=O and Si-O-CH3 bond. The highest turbidity reduction observed at the composition of nanosized CP5/P and silane treated nanosized CP5/P up to 93.89% and 93.98% respectively. However, no significant changes observed on turbidity reduction with increasing CP seeds content for both biocoagulant. Further, at these compositions, the TSS reduced up to 20% and 60% respectively. The DO value of wastewater decreased from the initial value and the increased the pH from 6.58 to 6.69 lead to the neutral condition. Therefore, the effectiveness of both untreated and silane treated biocoagulant were further confirmed upon textile wastewater with turbidity reduction achieved up to 7.84% and 14.54 % respectively. Overall, silane treatment enhanced the effectiveness of nanosized CP modified pullulan as biocoagulant

    From microbial fuel cell (MFC) to microbial electrochemical snorkel (MES): maximizing chemical oxygen demand (COD) removal from wastewater

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    The paper introduces the concept of the microbial electrochemical snorkel (MES), a simplified design of a “short-circuited” microbial fuel cell (MFC). The MES cannot provide current but it is optimized for wastewater treatment. An electrochemically active biofilm (EAB) was grown on graphite felt under constant polarization in an urban wastewater. Controlling the electrode potential and inoculating the bioreactor with a suspension of an established EAB improved the performance and the reproducibility of the anodes. Anodes, colonized by an EAB were tested for the chemical oxygen demand (COD) removal from urban wastewater using a variety of bio-electrochemical processes (microbial electrolysis, MFC, MES). The MES technology, as well as a short-circuited MFC, led to a COD removal 57% higher than a 1000 Ω-connected MFC, confirming the potential for wastewater treatment

    Removal of nitrogen pollutant from domestic wastewater

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    Water as a medium for waste transport would be easily contaminated by human activities. Many methods have been proposed to treat contaminated water to protect human health and biodiversity (Z. Daud et al., 2017). Due to upgrade the existing wastewater treatment plant facilities, the typically advanced technologies have been proposed to remove many types of pollutant, effectively (Tchobanoglous, Burton, & Stensel, 2004). The development of wastewater treatment plant needs to be considered leading economic indicators to have low operational and maintenance costs (Lewandowski, 2015; Shammas, Wang, & Wu, 2009). Aerobic digestion (AD) has been known since 1950 as biological wastewater treatment process to treat wastewater by removing the pollutants for instance colloids, organic compounds and suspended solids to avoid the excessive pollutants released into the receiving water (Shammas and Wang, 2007)
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