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Sustainable wastewater treatment necessitates the application of natural and green material in the approach. Thus, selecting a natural coagulant in wastewater treatment is a crucial step to prevent secondary environmental pollution due to residual inorganic coagulant in treated effluent. Present study investigated the application of Musa paradisiaca (banana) peels in domestic wastewater treatment. From the experimental results, the banana peels were found to have a higher yield with lower moisture content compared to the other fruit wastes. The surface charge of the banana peels was +6.53 meq/g MLSS while the recorded protein composition was 0.248 mg/L. The scanning electron microscopy (SEM) showed that banana peels has rough and pore surfaces compared to the others fruit wastes. At optimum conditions of 50 mg/L dosages, pH 4, and 100 rpm of agitational speed, the maximum turbidity removal of up to 89.9% with initial turbidity of 76 NTU was obtained. The banana peel was also evidenced in efficiently removing COD and NH4-N from domestic wastewater up to 80.0% and 62.5%, respectively. Overall, the findings suggested that Musa paradisiaca (banana) peels is efficient and suitable to be applied as the natural coagulant in treating domestic wastewater.

This study was aimed to study the potential of biogas (methane) production from vinasse wastewater in real full-scale application using a two-stage sequencing Up-flow High Rate Anaerobic Reactor (UHRAR), with effluent recirculation and substrate modification. Batch experiment was initially conducted prior full-scale application experiment. Batch experiment was done with experimental condition variable: undiluted sample (pH 6) and diluted samples (pH: 5; 6 and 7). pH and methane production were observed for 50 days. Full-scale application was carried out in two-stage UHRAR reactors with volume 60 m3, HRT 40 d and OLR 60.1 – 104 kg COD/m3.d. Observation was lasted for 32 d. Result from batch experiment showed that diluted samples achieved higher COD degradation and methane generation than undiluted sample. The optimum condition occurred at pH 7, with theoretical methane yield of 7.51 – 10.64 L CH4 per kg COD. While in full scale application, at day 32, COD removal was 71% (69.1 kg COD/d removed), with methane production was 36.72 m3 CH4/d. Methane production per COD removed was 0.53 m3 CH4/kg COD.d. Substrate modification and effluent recirculation could improve the substrate biodegradability, maintain microbial diversity and enrich nutrients in the reactor.

Acacia nilotica biomass was used to prepare activated carbon (ANAC-800) through pyrolysis at 800oC. The ANAC-800 was used as adsorbent for the fluoride sequestration in a batch and continuous column systems. The surface morphology, elemental composition as well as particle size distribution of the adsorbent was investigated with Scanning Electron Microscopy (SEM), Elemental and Particle Size Analyzers. What’s more, the influence of initial fluoride concentrations, column packing height and the flow rate on the column efficiency were examine while the efficiency of batch process as a function of contact time and temperature was also investigated. It was found that the kinetic of the process was best fitted with second order model, while the mechanism was best explained by interparticle diffusion model. In addition, the Langmuir Isotherm model showed that the maximum monolayer adsorption capacity of fluoride removal was 71.93 mg/g. The breakthrough curve and column data were well modelled by Adams-Bohart, Yoon-Nelson and Clark model. The models were judged using Akaike Information Criteria (AIC) values after statistical evaluation. ANAC-800 removed fluoride from aqueous solution comparably higher than other adsorbent in its category in batch and continuous column systems.

© 2022 The AuthorsThe rapidly expanding global energy demand is forcing a release of regulated pollutants into water that is threatening human health. Among various wastewater remediating processes, electrocoagulation (EC) has scored a monumental success over conventional processes because it combines coagulation, sedimentation, floatation and electrochemical oxidation processes that can effectively decimate numerous stubborn pollutants. The EC processes have gained some attention through various academic and industrial publications, however critical evaluation of EC processes, choices of EC processes for various pollutants, process parameters, mechanisms, commercial EC technologies and performance enhancement via other degradation processes (DPs) integration have not been comprehensively covered to date. Therefore, the major objective of this paper is to provide a comprehensive review of 20 years of literature covering EC fundamentals, key process factors for a reactor design, process implementation, current challenges and performance enhancement by coupling EC with pivotal pollutant DPs including, electro/photo-Fenton (E/P–F), photocatalysis, sono-chemical treatment, ozonation, indirect electrochemical/advanced oxidation (AO), and biosorption that have substantially reduced metals, pathogens, toxic compound BOD, COD, colors in wastewater. The results suggest that the optimum treatment time, current density, pulse frequency, shaking speed and spaced electrode improve the pollutants removal efficiency. An elegant process design can prevent electrode passivation which is a critical limitation of EC technology. EC coupling (up or downstream) with other DPs has resulted in the removal of organic pollutants and heavy metals with a 20% improved efficiency by EC-EF, removal of 85.5% suspended solid, 76.2% turbidity, 88.9% BOD, 79.7% COD and 93% color by EC-electroflotation, 100% decolorization by EC-electrochemical-AO, reduction of 78% COD, 81% BOD, 97% color by EC-ozonation and removal of 94% ammonia, 94% BOD, 95% turbidity, >98% phosphorus by aerated EC and peroxicoagulation. The major wastewater purification achievements, future potential and challenges are described to model the future EC integrated systems.

The continual discharge of emerging inorganic pollutants into natural aquatic systems and their negative effects on the environment have motivated the researchers to explore and develop clean and efficient water treatment strategies. Electrocoagulation (EC) is a rapid and promising pollutant removal approach that does not require any chemical additives or complicated process management. Therefore, inorganic pollutant treatment via the EC process is considered one of the most feasible processes. The potential developments of EC process may make the process a wise choice for water treatment in the future. Thus, the present study mainly focuses on the use of EC technology to remove nutrients and other emerging inorganic pollutants from water medium. The operating factors that influence EC process efficiency are explained. The major advancement of the EC technique as well as field-implemented units are also discussed. Overall, this study mainly focuses on emerging issues, present advancements, and techno-economic considerations in EC process.

While the potable water disinfection regimen has significantly reduced waterborne diseases, development of disinfection byproducts (DBP) during this process has brought a global threat to the environment and human health. The most notorious water pollutant, humic acid (HA), transforms into carcinogenic byproducts during the disinfection process (chlorination) of water treatment. HA removal methods are neither economic nor widely available. This study addresses the most urgent global issue of HA removal by developing an innovative and self-regenerative process based on a low-cost and self-regenerative calf bone char (CBC) that removed 92.1-100% of HA. CBC-based HA removal has not been described yet. The developed CBC, as a super adsorbent of HA, was initially characterized by a scanning electron microscope. Various parameters of adsorption/desorption and self-regeneration of CBC adsorbent were experimentally determined. Results show that prepared CBC with a 112 m

The natural product Catharanthus roseus and Lawsonia inermis leaf extract enhancement in the anti-corrosion potential green corrosion inhibitor (GIC) for Bacillus oleronius EN9 biofilm forms on mild steel (MS) in re-circulating water environment is demonstrated. This re-circulating water was enhancing the corrosion due to the temperature, pH, salinity, and chloride. Therefore, we need to improve the performance of the inhibitors. The chosen GIC inhibition was examined by antibacterial assay, weight loss, surface, and electrochemical analysis. L. inermis has shown the antibacterial activity (75%) against the corrosive bacteria Bacillus oleronius than the C. roseus (44%) optimum concentration of 20 ppm. L. inermis was selected for further studies and it reduces the corrosion rate up to 75 % in the 1% NaCl system. Scanning electron microscopy confirms the formation of the protective film on MS and GC–MS confirmed the presence of complex molecules of L. inermis. Therefore, the current work concluded that green corrosion inhibitor is suitable for the inhibition of biocorrosion of MS in the re-circulating system and a promising alternative for chemical inhibitor.

A novel nanomaterial, bacterial cellulose (BC), has become noteworthy recently due to its better physicochemical properties and biodegradability, which are desirable for various applications. Since cost is a significant limitation in the production of cellulose, current efforts are focused on the use of industrial waste as a cost-effective substrate for the synthesis of BC or microbial cellulose. The utilization of industrial wastes and byproduct streams as fermentation media could improve the cost-competitiveness of BC production. This paper examines the feasibility of using typical wastes generated by industry sectors as sources of nutrients (carbon and nitrogen) for the commercial-scale production of BC. Numerous preliminary findings in the literature data have revealed the potential to yield a high concentration of BC from various industrial wastes. These findings indicated the need to optimize culture conditions, aiming for improved large-scale production of BC from waste streams.

The use of renewable energy sources as a substitute for nonrenewable fossil fuels is urgently required. Algae biorefinery platform provides an excellent alternate to overcome future energy problems. However, to let this viable biomass be competent with existing feedstocks, it is necessary to exploit genetic manipulation and improvement in upstream and downstream platforms for optimal bio-product recovery. Furthermore, the techno-economic strategies further maximize metabolites production for biofuel, biohydrogen, and other industrial applications. The experimental methodologies in algal photobioreactor promote high biomass production, enriched in lipid and starch content in limited environmental conditions. This review presents an optimization framework combining genetic manipulation methods to simulate microalgal growth dynamics, understand the complexity of algal biorefinery to scale up, and identify green strategies for techno-economic feasibility of algae for biomass conversion. Overall, the algal biorefinery opens up new possibilities for the valorization of algae biomass and the synthesis of various novel products.

Pharmaceutical wastewater is a frequent kind of wastewater with high quantities of organic pollutants, although little research has been done in the area. Pharmaceutical wastewaters containing antibiotics and high salinity may impair traditional biological treatment, resulting in the propagation of antibiotic resistance genes. The potential for advanced oxidation processes (AOPs) to break down hazardous substances instead of present techniques that essentially transfer contaminants from wastewater to sludge, a membrane filter, or an adsorbent has attracted interest. Among a variety of AOPs, electrochemical systems are a feasible choice for treating pharmaceutical wastewater. Many electrochemical approaches exist now to remediate rivers polluted by refractory organic contaminants, like pharmaceutical micro-pollutants, which have become a severe environmental problem. The first part of this investigation provides the bibliometric analysis of the title search from 1970 to 2021 for keywords such as wastewater and electrochemical. We have provided information on relations between keywords, countries, and journals based on three fields plot, inter-country co-authorship network analysis, and co-occurrence network visualization. The second part introduces electrochemical water treatment approaches customized to these very distinct discarded flows, containing how processes, electrode materials, and operating conditions influence the results (with selective highlighting cathode reduction and anodic oxidation). This section looks at how electrochemistry may be utilized with typical treatment approaches to improve the integrated system's overall efficiency. We discuss how electrochemical cells might be beneficial and what compromises to consider when putting them into practice. We wrap up our analysis with a discussion of known technical obstacles and suggestions for further research.

The detection of pathogenic bacteria using biosensing techniques could be a potential alternative to traditional culture based methods. However, the low specificity and sensitivity of conventional biosensors, critically related to the choice of bio-recognition elements, limit their practical applicability. Mammalian antibodies have been widely investigated as biorecognition ligands due to high specificity and technological advancement in antibody production. However, antibody-based biosensors are not considered as an efficient approach due to the batch-to-batch inconsistencies as well as low stability. In recent years, antimicrobial peptides (AMPs) have been increasingly investigated as ligands as they have demonstrated high stability and possessed multiple sites for capturing bacteria. The conjugation of chemo-selective groups with AMPs has allowed effective immobilization of peptides on biosensor surface. However, the specificity of AMPs is a major concern for consideration as an efficient ligand. In this article, we have reviewed the advances and concerns, particularly the selectivity of AMPs for specific detection of pathogenic bacteria. This review also focuses the state-of-the-art mechanisms, challenges and prospects for designing potential AMP conjugated biosensors. The application of AMP in different biosensing transducers such as electrochemical, optical and piezoelectric varieties has been widely discussed. We argue that this review would provide insights to design and construct AMP conjugated biosensors for the pathogenic bacteria detection.

In this study, a novel miniature terrestrial microbial fuel cells (TMFCs) inoculated with commercial garden soil was developed to generate bioelectricity. The startup and stabilization were evaluated as open circuit voltage (OCV). The effect of an enrichment procedure with 12 mM, 37 mM, and 61 mM Na-acetate under anaerobic conditions was assessed. The initial OCV was 0.55 ± 0.02 V, 0.58 ± 0.01 V and 0.75 ± 0.15 V in the TMFCs inoculated with 12 mM, 37 mM and 61 mM Na-acetate, respectively. The OCV increased in relation with the substrate input. The average OCV during stable operation was as follows: 1.01 ± 0.006 V (12 mM), 1.02 ± 0.005 V (37 mM) and 1.13 ± 0.003 V (61 mM). The time required for peaking the maximum voltage and its stabilization was significantly decreased up to ~2 h. Hence, it is concluded that the OCV output of the miniature TMFCs was comparable or even higher than macroscale reactors and it is optimal for rapid detection of the electrogenic process in soil samples. Furthermore, the reactor design displayed simplicity and the electrode area to reactor volume ratio was enhanced in contrast to macroscale TMFCs.

Characterization and production of biosurfactant by a novel bacterial strain isolated from an Iranian oil field was investigated. Biosurfactant has wide applications in oil recovery. A number of ten strains of Bacillus sp. were isolated from oil-contaminated soil samples to study biosurfactant production. Among strains studied, the strain 2IR was selected as a potent biosurfactant-producing bacterium. The identification of the strain 2IR was carried out using scanning electron microscopy, biochemical tests and partial 16S rRNA gene sequencing with generating a phylogenetic tree. Accordingly, the new strain was identified as Bacillus pumilus 2IR. The biosurfactant produced by the strain 2IR was characterized by high performance liquid chromatography, fourier transform infrared spectroscopy and proton nuclear magnetic resonance test. The tests results characterized the biosurfactant produced as a lipopeptide type. In order to attain the highest surface tension reduction of the lipopeptide biosurfactant, culture medium of the strain 2IR was optimized. Experimental results showed that glucose, crude oil, potassium nitrate and ammonium sulfate were pivotal components of the culture medium for biosurfactant synthesis by B.pumilus 2IR. Similar results revealed that optimum medium compositions were 30.31 g/L glucose, 0.8% (v/v) crude oil, 2.88 g/L potassium nitrate and 2.4 g/L ammonium sulfate. A surface tension value of 30 mN/m was obtained in optimum conditions. This research presents new indigenous strain B. pumilus 2IR for synthesis of biosurfactant usable for possible in situ oil recovery.

Since the last century, the search for clean and renewable energy is going on. This process will continue until there is a stable solution available as an alternative to fossil fuels. Several energy-producing products arise from photosynthetic-organisms like biofuel, bioelectricity, and there are various methods also available for the extraction of these products. Microbial fuel cells (MFCs) are energy transducers which convert organic matter directly into electricity, through the process of anaerobic respiration of microorganisms. Now a day’s researchers have taken as a challenge to use algae along with the bacterial communities to provide an organic carbon fuel source for the MFCs. This paper describes the potential application of algal biomass in the field of bioelectricity. Till now, many scientific experiments conducted all around the world to demonstrate how well efficient is this green photosynthetic organism capable of producing electricity along with its other applications like biofuel, demand in the food industry, and much more. The present manuscript aimed to provide an overview of the potential use of algae as a biocatalyst in MFCs. Further, this article also provides the current status of numerous countries which are excelled in the field of bioelectricity generation.

The enhancement of the production of lipopeptide biosurfactant by Bacillus pumilus 2IR as an oil field-isolated bacterium was investigated in the fed-batch fermentation using a 5-L bioreactor. The initial study on the culture medium composition used for biosurfactant synthesis revealed that biosurfactant production was greatly affected by glucose, crude oil, potassium nitrate and ammonium sulfate as pivotal carbon and nitrogen sources which were utilized for biosurfactant synthesis in the bioreactor. The results obtained from the batch fermentation process in the bioreactor showed that the quantities of biomass and biosurfactant produced were 4.15 and 0.98g/L, respectively. Similar results revealed that fed-batch fermentation led to the production of 5.71g/L biomass and 1.06g/L biosurfactant in the bioreactor.

Continuous fermentation of dilute acid-pretreated de-oiled rice bran (DRB) to butanol by the Clostridium acetobutylicum YM1 strain was investigated. Pretreatment of DRB with dilute sulfuric acid (1%) resulted in the production of 42.12 g/L total sugars, including 25.57 g/L glucose, 15.1 g/L xylose and 1.46 g/L cellobiose. Pretreated-DRB (SADRB) was used as a fermentation medium at various dilution rates, and a dilution rate of 0.02 h−1 was optimal for solvent production, in which 11.18 g/L of total solvent was produced (acetone 4.37 g/L, butanol 5.89 g/L and ethanol 0.92 g/L). Detoxification of SADRB with activated charcoal resulted in the high removal of fermentation inhibitory compounds. Fermentation of detoxified-SADRB in continuous fermentation with a dilution rate of 0.02 h−1 achieved higher concentrations of solvent (12.42 g/L) and butanol (6.87 g/L), respectively, with a solvent productivity of 0.248 g/L.h. This study showed that the solvent concentration and productivity in continuous fermentation from SADRB was higher than that obtained from batch culture fermentation. This study also provides an economic assessment for butanol production in continuous fermentation process from DRB to validate the commercial viability of this process.

A two-chambered microbial fuel cell (MFC), which can function on the self-driven bioelectrogenic activity operated on anaerobically digested distillery waste (ADDW) i.e. wastewater post anaerobic digestion was designed and fabricated in the laboratory. MFC was evaluated for production of bioelectricity with a simultaneous reduction in the carbon content. Using a surface response methodology with a Box-Behnken design (BBD), operating conditions such as the concentration of antifoam, pH, and resistance were optimized and it was found that the pH and resistance were optimum at 8.3 and 1000 0, respectively with no antifoam in the system. Under optimum conditions, 31.49 Wm-3 was generated, and 60.78 +/- 0.95% total organic carbon was degraded. We revealed that the fermentative bacteria generated organic acids mainly acetate from dextrose present in ADDW and electrogenic bacteria oxidized acetate in a successive manner to generate electrons, which was confirmed by gas chromatography. The development of biofilm analyzed by scanning electron microscope (SEM) was found to be crucial in the transfer of electrons directly to the anode and was confirmed by cyclic voltammetry experiments. Identification of bacteria from biofilm by both culture and denaturing gradient gel electrophoresis methods found bacteria belonging to phylum Firmicutes and gamma-proteobacteria. The study of successive nature of bacterial metabolism to generate electricity could play an important role in the production of electricity in a continuous mode of operation using MFCs fed with ADDW for further reduction of carbon content post anaerobic digestion for the benefit for the environment. Thus MFC can be used as a complementary technology to anaerobic digestion. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Microbial electrochemical systems (MESs) are an attracting technology for the disposal of wastewater treatment and simultaneous energy production. In MESs, at the anode microorganisms through the catalytic activity generates electrons that can be converted into electricity or other valuable chemical compounds. Microorganisms those having ability to donate and accept electrons to and from anode and cathode electrodes, respectively are recognized as 'exoelectrogens'. In the MESs, it renders an important function for its performance. In the present mini-review, we have discussed the role of microbiome including pure culture, enriched culture and mixed culture in different BESs application. The effects of operational and biological factors on microbiome development have been discussed. Further discussion about the molecular techniques for the evaluation of microbial community analysis is addressed. In addition different electrochemical techniques for extracellular electron transfer (EET) mechanism of electroactive biofilms have been discussed. This review highlights the importance of microbiome in the development of MESs, effective operational factors for exo-electrogens activities as well their key challenges and future technological aspects are also briefly discussed.

An air exposed single-chamber microbial fuel cell (SCMFC) using microalgal biocathodes was designed. The reactors were tested for the simultaneous biodegradation of real dye textile wastewater (RTW) and the generation of bioelectricity. The results of digital image processing revealed a maximum coverage area on the biocathodes by microalgal cells of 42%. The atmospheric and diffused CO2 could enable good algal growth and its immobilized operation on the cathode electrode. The biocathode-SCMFCs outperformed an open circuit voltage (OCV), which was 18%–43% higher than the control. Furthermore, the maximum volumetric power density achieved was 123.2 ± 27.5 mW m−3. The system was suitable for the treatment of RTW and the removal/decrease of COD, colour and heavy metals. High removal efficiencies were observed in the SCMFCs for Zn (98%) and COD (92–98%), but the removal efficiencies were considerably lower for Cr (54–80%). We observed that this single chamber MFC simplifies a double chamber system. The bioelectrochemical performance was relatively low, but the treatment capacity of the system seems encouraging in contrast to previous studies. A proof-of-concept experiment demonstrated that the microalgal biocathode could operate in air exposed conditions, seems to be a promising alternative to a Pt cathode and is an efficient and cost-effective approach to improve the performance of single chamber MFCs.

Microbial fuel cells represent an innovative technology which allow simultaneous waste treatment, electricity production, and environmental monitoring. This study provides a preliminary investigation of the use of terrestrial Single chamber Microbial Fuel Cells (SMFCs) as biosensors. Three cells were created using Andean soil, each one for monitoring a BOD concentration of synthetic washed rice wastewater (SRWW) of 10, 100, and 200 mg/L for SMFC1, SMFC2 and SMFC3, respectively. The results showed transient, exponential, and steady stages in the SMFCs. The maximum open circuit voltage (OCV) peaks were reached during the elapsed time of the transient stages, according to the tested BOD concentrations. A good linearity between OCV and time was observed in the increasing stage. The average OCV in this stage increased independently of the tested concentrations. SMFC1 required less time than SMFC2 to reach the steady stage, suggesting the BOD concentration is an influencing factor in SMFCs, and SMFC3 did not reach it. The OCV ratios were between 40.6–58.8 mV and 18.2–32.9 mV for SMFC1 and SMFC2. The reproducibility of the SMFCs was observed in four and three cycles for SMFC1 and SMFC2, respectively. The presented SMFCs had a good response and reproducibility as biosensor devices, and could be an alternative for environmental monitoring.