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The aim of this work was to evaluate the influence of FMA biofilm on nutrient removal through the filtration membrane air-cathode (FMA) replacement test. The result showed that the biofilm accounted for only 29.9% of the COD removal, while 82.9% of the TN removal can be due to the contribution of the FMA biofilm. The microbial community analysis showed that most of the primary genus in the FMA biofilm were TN removal related bacteria. This quantitative determination of the FMA biofilm influence on COD and TN removal would promote the further optimization of the MFC reactor with FMA for higher wastewater treatment efficiency. [ABSTRACT FROM AUTHOR]

[Display omitted] • PEF alleviated the inhibition of COD on anammox and raised TN removal by 16.99% on average. • PEF upgraded the abundance of anammox bacteria subordinate to the phylum Planctomycetes by 9.64%. • PEF led to a great increase in the relative abundance of genes encoding hzs and hdh by 71.63% and 83.74% in the presence of COD. This paper aims to investigate the function of a pulsed electric field (PEF) in the anaerobic ammonia oxidation (anammox) process after adding certain chemical oxygen demand (COD) through integrated network and metagenomics analyses. The findings showed that the presence of COD was detrimental to anammox, but PEF could significantly reduce the adverse effect. The total nitrogen removal in the reactor for applying PEF was 16.99% higher on average than the reactor for only dosing COD. Additionally, PEF upgraded the abundance of anammox bacteria subordinate to the phylum Planctomycetes by 9.64%. The analysis of molecular ecological networks promulgated that PEF resulted in an increase in network scale and topology complexity, thereby boosting the potential collaboration of the communities. Metagenomics analyses demonstrated that PEF dramatically promoted anammox central metabolism in the presence of COD, specifically enhancing pivotal N functional genes (hzs , hdh , amo , hao , nas , nor and nos). [ABSTRACT FROM AUTHOR]

A fixed film bioreactor for the denitrification of the effluent from an anaerobic membrane bioreactor (AnMBR) treating domestic wastewater was designed, built and investigated. After anaerobic treatment, the wastewater usually has a low C/N ratio (∼1.3), and a remaining chemical oxygen demand of around 117 mg O 2 /L, which is not enough to make conventional heterotrophic denitrification possible. That effluent also holds methane and sulfide dissolved and oversaturated after leaving the AnMBR. This paper demonstrates the feasibility of using these reduced compounds as electron donors in order to remove 80 mg NO x − -N/L at 18 °C and 2 h of hydraulic retention time. In addition, the influence of the NO 2 − /NO 3 − ratios in the feed was studied. Total nitrogen removal was achieved in all the cases studied, except for a feed with 100% NO 3 − . Methane was the main electron donor used to remove the nitrites and nitrates, with a participation rate of over 70%. [ABSTRACT FROM AUTHOR]

Urban sludge was treated by Hydrothermal carbonization (HTC). The effect of hydrothermal carbonization temperature, mixing with or without catalysts on solid products yield, heavy metal contents, turbidity and COD value was evaluated. The result showed solid products yield decreased from 92.04% to 52.65% when the temperature increased from 180 to 300 °C. And the Cu, Zn, and Pb contents under exchangeable states decreased and reached discharge standard. Addition of FeCl 3 or Al(OH) 3 resulted in a significant increase in the exchangeable states of Zn, Pb, Cr, and Cd and decrease in their residual states. The turbidity and COD value of hydrothermal liquid decreased from 450° to 175°, and 13 to 6.8 g/L, with increasing hydrothermal temperature. Comparison with HTC, solid productivity from low-temperature pyrolysis is higher. The exchangeable states of Cu, Zn, and Cr exceeded the limiting values. Our results show HTC can facilitate transforming urban sludge into no-pollution and energy-rich products. [ABSTRACT FROM AUTHOR]

A mixed culture of microalgae, containing two Scenedesmus species, was analysed to determine its potential in coupling of pulp and paper mill effluent treatment and microalgal cultivation. Laboratory studies suggested that 60% concentration of wastewater was optimum for microalgal cultivation. A maximum of 82% and 75% removal of BOD and COD respectively was achieved with microalgal cultivation in outdoor open pond. By the end of the cultivation period, 65% removal of NO 3 -N and 71.29% removal of PO 4 -P was observed. The fatty acid composition of mixed microalgal culture cultivated with effluent showed the palmitic acid, oleic acid, linoleic acid and α-linolenic acid as major fatty acids. The results obtained suggest that pulp and paper mill effluent could be used effectively for cultivation of microalgae to minimise the freshwater and nutrient requirements. [ABSTRACT FROM AUTHOR]

Periphyton-based bioreactors are widely accepted for removing various pollutants from wastewater; however, the slow start-up and low efficiency in widely fluctuating temperatures limit its application. A spiral periphyton bioreactor (SPR) was developed and its COD removal capability and the associated microbial communities were investigated. This SPR can be easily backwashed to stimulate periphyton growth and efficiently remove COD at temperatures ranging from 4 to 30 °C. The species richness and evenness of the periphyton community increased during domestication, while its functional diversity and organic carbon metabolic vitality were higher after 30 days domestication. Cyanobacteria were the main components of the SPR and produced an aerobic environment, while Alphaproteobacteria , Betaproteobacteria , Gammaproteobacteria and Sphingobacteria were the microorganisms responsible for COD removal. This study provides valuable insights into changes in pivotal microorganisms of the periphyton community during domestication, and indicates that SPR is simple to operate and efficient in COD removal. [ABSTRACT FROM AUTHOR]

The efficiency of a bioelectrochemical treatment system (BET) to treat complex paper and pulp wastewater at two different pH conditions (6 and 7) in comparison with conventional anaerobic treatment process (AnT) was evaluated. Among the operating conditions, BET showed good treatment efficiency at pH 7 in terms of COD (BET/AnT: 55%/51%), nitrates (33.5%/19.1%), phosphates (33%/19%) and sulfates (58%/41%) in removal. The effluent obtained from BET system was subjected to coagulation for further treatment which showed good COD removal (BET/AnT, 95%/69%) and color (100%/68%). Bioelectrochemical analysis revealed higher catalytic currents in BET than AnT specific to oxidation and reduction. Besides, derivative of cyclic voltammetric scans (DCV) also supported the involvement of various membrane bound electron transferring complexes like FAD(H) bound enzymes, ubiquinone, NADH + /H + bound enzymes, etc. Experimental results demonstrated that BET system can be a viable platform to treat complex wastewaters with simultaneous energy recovery in integrated approach. [ABSTRACT FROM AUTHOR]

In the present study, a sequential treatment process was carried out using a fungal sp. ( Phanerochaete sp.) followed by a bacterial sp. ( Pseudomonas sp.) for the degradation and detoxification of contaminants in landfill leachate. The process was optimized using Box–Behnken design (BBD) and response surface methodology (RSM) for three variables (C source, N source and duration), while monitoring two responses (% COD and color removal). After treatment in a bioreactor under optimized conditions, enhanced removal of COD (76.9%) and color (45.4%) was observed. Further, GC–MS analysis of metabolites detected at different stages of treatment showed formation of degradation products of lignin and polycyclic aromatic compounds. Treatment efficiency was finally evaluated by the alkaline comet assay in HepG2 human hepato-carcinoma cells. The results indicated no statistically significant DNA damage at the end of the treatment, making the effluent suitable to be discharged conforming to the safety standards. [ABSTRACT FROM AUTHOR]

A bio-cathode microbial fuel cell (MFC) with tubular membrane was integrated to construct a microbial fuel cell–tubular membrane bioreactor (MFC–TMBR) system, in which the bio-cathode MFC was developed as a biosensor for COD real-time monitoring in TMBR and the performance was analyzed in terms of its current variation caused by operation parameters. With a constant anode potential, the effect of HRT demonstrated that higher rate of mass transport increased the response of the system. The system was further explored an inverse relationship between TMP and current peak by using EPS concentration under the different MLSS concentration. The sensor output had a linear relationship with COD up to 1000 mg/L (regression coefficient, R 2 = 0.97) and MLSS (regression coefficient, R 2 = 0.94). The simple and compact bio-cathode MFC biosensor for TMBR using MFC–TMBR integrated system showed promising potential for direct and economical COD online monitoring, and provided an opportunity to widen the application of MFC-based biosensor. [ABSTRACT FROM AUTHOR]

Abstract: Piggery wastewater that is used for microalgae cultivation has usually been treated by secondary treatment processes. The present study investigates mixotrophic cultivation of the green microalgae Chlorella pyrenoidosa with primary piggery wastewater that has merely been diluted before use. The biomass productivity of the microalgae exhibited a positive linear correlation with the initial COD values, which ranged from 250 to 1000mg/L. Nutrients in the piggery wastewater were removed efficiently; for example, the removal rate of ammonium was over 90% in all diluted samples. Profiles of fatty acids in the algal lipids were different after cultivation in piggery wastewater medium compared to Bristol’s solution. The maximum lipid productivity of 6.3mgL−1 day−1, which was achieved when the initial COD was 1000mg/L, is not superior to other reports, but it suggests a convenient way to reduce the high organic content of piggery waste with the production of algal lipids. [Copyright &y& Elsevier]

Abstract: A two-step anaerobic baffled reactor (ABR-1 and ABR-2) for H2 production from municipal food waste (MFW) was investigated at a temperature of 26°C. In ABR-1, the average yield of H2 at an HRT of 26h and OLR of 58kg COD/m3 d was 250ml H2/g VS removed. As unexpected; the H2 production in the ABR-2 was further increased up to 370ml H2/gVS removed at a HRT of 26h and OLR of 35 kgCOD/m3 d. The total H2 yield in the two-step process was estimated to be 4.9mol H2/mol hexose. The major part of H2 production in the ABR-1 was due to the conversion of CODparticulate (36%). In the ABR-2 the H2 yield was mainly due to the conversion of COD in the soluble form (76%). Based on these results MFW could be ideal substrate for H2 production in a two-step ABR processes. [Copyright &y& Elsevier]

Abstract: Most restaurant operators in Hong Kong run their business in commercial buildings. Many of them fail to meet oil and grease (O & G) limits. The O & G and Chemical Oxygen Demand (COD) content of the effluents can be reduced to meet government prescribed standards using a combination of compressed air and chemical treatment in existing two-chamber grease traps. A mean level of 41mg/L and a mean removal of 92.7% of O & G can be achieved for a typical fast food restaurant. COD reduction can further be improved by dissolved air flotation enhanced with chemicals. Sludge generated from flotation treatment of the wastewaters can be recycled as a fertilizer to give a mean total nitrogen content of 13,217mg/kg and a mean total phosphorus level of 1133mg/kg. Moreover, it can also be utilized as a biofuel to give a mean calorific value of 6690Cal/g which is equivalent to that of coal. [Copyright &y& Elsevier]

Abstract: Jumbo squid (Dosidicus gigas) mantle muscle was cooked simulating industrial procedures (95°C×25min, 1.2:5 muscle:water ratio). The effluent produced was analyzed for chemical and biochemical oxygen demands (COD and BOD5, respectively), proximate analysis, flavor-related compounds (free amino acids, nucleotides and carbohydrates) and SDS–PAGE. The COD and BOD5 exhibited variation among samplings (N =3) (27.4–118.5g O2/L for COD and 11.3–26.7g O2/L for BOD5). The effluent consisted of 1% total solids, 75% of which represented crude protein. Sixty percent of the total free amino acid content, which imparts flavor in squid species, corresponded to glutamic acid, serine, glycine, arginine, alanine, leucine and lysine. The nucleotide concentration followed this order, Hx≫ADP>AMP>ATP>IMP>HxR. The variation observed in the present work was probably due to physiological maturity differences among the squid specimens (i.e., juvenile versus mature). Solids present in squid cooking effluent could be recovered and potentially used as flavor ingredients in squid-analog production by the food industry. [Copyright &y& Elsevier]

The anammox process, under different organic loading rates (COD), was evaluated using a semi-continuous UASB reactor at 37°C. Three different substrates were used: initially, synthetic wastewater, and later, two different pig manure effluents (after UASB-post-digestion and after partial oxidation) diluted with synthetic wastewater. High ammonium removal was achieved, up to 92.1±4.9% for diluted UASB-post-digested effluent (95mg CODL−1) and up to 98.5±0.8% for diluted partially oxidized effluent (121mgCODL−1). Mass balance clearly showed that an increase in organic loading (from 95mg CODL−1 to 237mg CODL−1 and from 121mg CODL−1 to 290mg CODL−1 for the UASB-post-digested effluent and the partially oxidized effluent, respectively) negatively affected the anammox process and facilitated heterotrophic denitrification. Partial oxidation as a pre-treatment method improved ammonium removal at high organic matter concentration. Up to threshold organic load concentration of 142mg CODL−1 of UASB-post-digested effluent and 242mg CODL−1 of partially oxidized effluent, no effect of organic loading on ammonia removal was registered (ammonium removal was above 80%). However, COD concentrations above 237mgL−1 (loading rate of 112mg CODL−1 day−1) for post-digested effluent and above 290mgL−1 (loading rate of 136mg CODL−1 day−1) for partially oxidized effluent resulted in complete cease of ammonium removal. Results obtained showed that, denitrification and anammox process were simultaneously occurring in the reactor. Denitrification became the dominant ammonium removal process when the COD loading was increased. [Copyright &y& Elsevier]

The catalytically oxidized olive mill wastewater (OMW) was subjected to continuous anaerobic treatment using two treatment schemes. The 1st step in both schemes was an up-flow anaerobic sludge blanket (UASB) reactor (20l). The 2nd step was either a hybrid UASB reactor or a classical one (10l, each). The 1st stage was operated at constant hydraulic retention time (HRT) of 24h. The organic loading rate (OLR) varied from 3.4 to 4.8kgCOD/m3 d depending on the quality of the pretreated wastewater. The results obtained indicated that, the 1st step UASB reactor achieved a COD percentage removal value of 53.9%. Corresponding total BOD5 and TSS removal were 51.5% and 68.3%, respectively. The results obtained indicated that the hybrid UASB reactor as a 2nd step produced better quality effluent as compared to the classical one. This could be attributed to the presence of the packing curtain sponge with active biomass in the sedimentation part of hybrid UASB reactor which minimizes suspended solids washout, consequently enhancement of the efficiency of the reactor. Available data showed that a two stage system consisting of a classical and a hybrid UASB reactor operated at a total HRT of 48h and OLR of 2.0kgCOD/m3 d provided promising results. Removal values of CODtotal, BOD5total, TOC, VFA, oil and grease were 83%, 84%, 81%, 93% and 81%, respectively. Based on the available data, the use of a two stage anaerobic system consisting of a classical UASB reactor followed by a hybrid UASB as a post-treatment step for catalytically oxidized OMW is recommended. [Copyright &y& Elsevier]

Abstract: Sewage sludge samples representing different stages during waste water and sewage sludge treatment were collected at four Austrian municipal waste water treatment plants. Changes of sludge composition are reflected by a specific infrared spectroscopic pattern. Anaerobically digested sludge was subjected to aeration in lab-scale reactors in order to find out if post-aeration after anaerobic digestion provides enhanced organic matter degradation and stabilization. Spectral data were evaluated by means of multivariate statistics. Similar spectral characteristics of sludge degradation stages were visualized by principal component analysis. The effect of additional aerobic treatment of anaerobically stabilized sludge was revealed by discriminant analysis that distinguishes additionally aerated sludge from all the other degradation stages of sludge because of changes in the spectral pattern by increasing stabilization. Based on partial least squares regression (PLSR) a correlation coefficient of R 2 =0.91 was found between spectral characteristics and the chemical oxygen demand (COD). [Copyright &y& Elsevier]

This paper presents the integrated removal of carbon (measured as chemical oxygen demand i.e. COD) and NO x –N by sequentially adapted sludge, studied in an airlift reactor (ALR). Simultaneous removal of COD and nitrate occurs by denitrification (anoxic) and oxidation (aerobic). Aerobic (riser) and anoxic (remaining part) conditions prevail in different parts of the reactor. Studies were carried out in a 42L ALR operated at low aeration rate to maintain anoxic and aerobic conditions as required for denitrification and COD removal, respectively. The sludge was adapted sequentially to increasing levels of NO x –N and COD over a period of 45 days. Nitrate removal efficiency of the sludge increased due to adaptation and degraded 900ppm NO3–N completely in 2h (initially the sludge could not degrade 100ppm NO3–N). The performance of the adapted sludge was tested for the degradation of synthetic waste with COD/N loadings in the range of 4–10. The reduction of COD was significantly faster in the presence of NO x –N and was attributed to the availability of oxygen from NO x –N and distinct conditions in the reactor. This hypothesis was justified by the material balance of COD. [Copyright &y& Elsevier]

The aim of this work was to characterise wine-related wastewaters and ascertain the wastewater concentrations that were optimal for treatment by Trametes pubescens. Laccase production was also monitored. Crudely purified laccase was tested independently to determine its role in phenolic compounds degradation and colour change. The fungal treatment resulted in decreases in the wastewater chemical oxygen demand of up to 83±2.1%, phenolic compounds of 87±1.6% and colour of 88±4.7%. Although laccase treatment lowered total phenolics by up to 61±0.5%, the colour was increased by up to 160±5%, indicating the formation of colour-rich compounds. Trametes pubescens MB 89 greatly improved the quality of all six wastewaters tested, although two wastewaters had to be diluted to below 50% to allow for bioremediation by the submerged fungal culture. Laccase synthesis greater than 1500U/l was obtained in all wastewaters, with a maximum of 8997U/l. The complete fungal system was found to be superior to enzymatic treatment alone. Enzymatic treatment reduced the total phenols but did little to improve the colour of the wastewaters, and in the case of wine lees significantly increased the colour. [Copyright &y& Elsevier]

Abstract: The aim of this study was the assessment of reduction of chemical oxygen demand (COD) and biological oxygen demand (BOD) of wastewater from coffee processing plant using activated carbon made up of Avacado Peels. The complete study was done in batch mode to investigate the effect of operating parameters. The results of the COD and BOD concentration reduction with avocado peel carbon (APC) and commercial activated carbon (CAC) were compared and optimum operating conditions were determined for maximum reduction. Adsorption isotherm was also studied besides the calculation of optimum treatment parameters for maximum reduction of COD and BOD concentration from effluent of the coffee processing plant. The maximum percentage reduction of COD and BOD concentration under optimum operating conditions using APC was 98.20% and 99.18% respectively and with CAC this reduction was 99.02% and 99.35% respectively. As the adsorption capacity of APC is comparable with that of CAC for reduction of COD and BOD concentration, it could be a lucrative technique for treatment of domestic wastewater generated in decentralized sectors. [Copyright &y& Elsevier]

Abstract: The objective of this work is to study COD and BOD reduction of domestic wastewater using discarded material based mixed adsorbents (mixed adsorbent carbon, MAC and commercial activated carbon, CAC) in batch mode. Under optimum conditions, maximum reduction and maximum COD and BOD reduction achieved using MAC and CAC was 95.87% and 97.45%; and 99.05% and 99.54%, respectively. Results showed that MAC offered potential benefits for COD and BOD removal from wastewater. [Copyright &y& Elsevier]

Abstract: Decolorization of two monoazo dyes, acid orange 6 (AO6) and acid orange 7 (AO7), were studied in sequential fixed-film anaerobic batch reactor (SFABR) with varying dye concentrations and 500mg/L glucose as the co-substrate. More than 90% dye decolorization could be achieved, even at 300mg/L, with both AO6 and AO7 and dye decolorization rates were 168mg/L/d and 176mg/L/d, respectively. COD removals with these two monoazo dyes were significantly different, as 75% and 35% decrease were observed with AO6 and AO7, respectively. UV–visible spectral as well as HPLC analysis of SFABR treated effluent showed the accumulation of 4-aminobenzenesulfonate (4-ABS) from AO6 and AO7. Aminoresorcinol (AR) formed from AO6 decolorization could not be detected at the end of SFABR cycle. This along with high COD removal indicated its further degradation. Formation of pink coloration on exposure to air indicated the presence of 1-amino-2-naphthol (AN) in AO7 fed reactor effluent. Thus both 4-ABS and AN were resistant to further degradation under anaerobic conditions. Presence of nitrate did not decrease the observed decolorization at the end of 24h SFABR cycle, although initial rate was decreased. This indicates the suitability of SFABR configuration for the treatment of azo-dye containing wastewaters in the presence of nitrate. [Copyright &y& Elsevier]

Abstract: This research investigated the feasibility of coarse/fine sand filtration for removing organic materials from turkey processing wastewater. Sand filtration was tested with three organic and hydraulic loadings. Six two-layer sand bioreactors were in three groups, each with 5cm layer of pea gravel at the bottom to support layers of fine sand (46cm) and coarse sand (15cm) to a height of 66cm. The bioreactors were inoculated with a mixture of 20% (vol/vol) of wastewater lagoon sludge, 40% (vol/vol) of turkey processing wastewater, and 40% (vol/vol) of BOD5 dilution water before starting the column operation with turkey processing wastewater. The wastewater contained 1270±730mgCOD/L and was applied to each sand bioreactor at hydraulic loading rates of 264, 132 and 66L/m2/day. Each group comprised duplicate columns with the identical hydraulic loading. A commercially available detergent, IvoryTM, was added to the wastewater at 0.04% (wt/vol). Maximum treatment efficiencies were reached within a week. The removal of TOC and BOD5 was >94% during 80 days of column operation at low and medium hydraulic loading rates (⩽132L/m2/day). The removal at the highest hydraulic loading rate (264L/m2/day) declined after the appearance of a black zone in the top layer of fine sand on day 30 for one reactor and day 50 for the other. The sand filtration in this study represents a feasible treatment for turkey processing wastewater and its efficiency and the life span of the process are associated with the extent of hydraulic loading of the sand bioreactors. [Copyright &y& Elsevier]

Abstract: Heavy oil-produced water from China’ Liaohe Oilfield was purified in a surface flow constructed wetland (SFCW) during a 3-yr field experiment. Treatment showed high mean removal efficiencies of 80%, 93%, 88% and 86% for COD, oil, BOD and TKN, respectively for reed bed #1 and 71%, 92%, 77%, and 81% for COD, oil, BOD and TKN, respectively for reed bed #2. The results also showed that in the third year of the system’s operation, the oil-produced water had mainly positive impacts on the reed’s health parameters. Thus, reed can be used as a feasible wetland macrophyte for treating such wastewater, and this SFCW system can operate for a long time. [Copyright &y& Elsevier]

Abstract: Pilot studies were carried out for the treatment of pre-hydrolysate liquor (PHL), a high strength effluent (COD: 70,000–80,000mg/l) emanating from a rayon grade pulp mill using up-flow anaerobic sludge blanket reactor (UASB). Substrate inhibition was avoided with optimum COD feed of around 25,000mg/l. This was achieved by diluting the PHL with a low strength effluent stream known as alkali back wash (ABW) available in the plant and also by partially recycling the reactor liquid outlet. An optimum organic loading rate (OLR) of 10 could be achieved with a COD reduction of 70–75%, a BOD reduction of 85–90% and a methane yield of 0.31–0.33m3/kg of COD reduced. The pilot scale studies also revealed that addition of milk of lime (MOL) was essential for neutralization and buffering and DAP and urea to supplement the nutrients in the PHL. Based on the pilot studies, a full-scale high rate biomethanation plant was designed and erected for treating the PHL, which after some modification showed similar performance for COD, BOD reduction and methane yield. [Copyright &y& Elsevier]

Abstract: The electrochemical oxidation of the digested effluent from anaerobic digestion of dairy manure was investigated in this study. The digested effluent sample containing with suspended solids was pretreated by filtration for the electrochemical experiment. The influence of direct anodic oxidation and indirect oxidation was evaluated through the use of dimensionally stable anode (DSA) and Ti/PbO2 as anode. The decreasing rate of chemical oxygen demand (COD) was higher at lead dioxide coated titanium (Ti/PbO2) electrode than at DSA, however the DSA was preferred anode for the decrease of ammonium nitrogen (NH4-N) due to the control of ammonium nitrate (NO3-N) accumulation. The results showed that the filtration of suspended solids as a pretreatment and addition of NaCl could improve the whole removing efficiency of NH4-N in the digested effluent on electrochemical oxidation. [Copyright &y& Elsevier]

Abstract: An investigation was conducted to explore the lignin-degrading capacity of attached-growth white-rot fungi. Five white-rot fungi, Phanerochaete chrysosporium, Pleurotus ostreatus, Lentinus edodes, Trametes versicolor and S22, grown on a porous plastic media, were individually used to treat black liquor from a pulp and paper mill. Over 71% of lignin and 48% of chemical oxygen demand (COD) were removed from the wastewater. Several factors, including pH, concentrations of carbon, nitrogen and trace elements in wastewater, all had significant effects on the degradation of lignin and the removal of COD. Three white-rot fungi, P. chrysosporium, P. ostreatus and S22, showed high capacity for lignin degradation at pH 9.0–11.0. The addition of 1gl−1 glucose and 0.2gl−1 ammonium tartrate was beneficial for the degradation of lignin by the white-rot fungi studied. [Copyright &y& Elsevier]

Abstract: The bio-toilet is becoming commercially available and it is actually used in Japan in public parks, sightseeing areas, and households; however, the biological activity in the system during degradation of toilet wastes, particularly faeces, is unknown. Thus, in this study activity of microorganisms in the bio-toilet system during degradation of faeces was assessed through the quantification of reductions in total solids (TS), volatile solids (VS), and chemical oxygen demand (COD) during batch tests in laboratory-scale composting reactors. Additionally, the fate of nitrogen and its transformation processes in such reactors were evaluated. TS, VS, and COD reductions were on the order of 56%, 70%, and 75%, respectively, irrespective of the organic loading regarded. Total nitrogen (T-N) reductions quantified 94%, regardless of the organic loading. Furthermore, all T-N reductions observed during composting were equivalent to the NH3-N released from the reactor, i.e., 94% of ammonia was lost. [Copyright &y& Elsevier]

Abstract: Thermophilic aerobic digestion (TAD) of a model agricultural waste, potato peel slurry, at soluble chemical oxygen demand (COD) load equivalent to approximately 8.0 gl−1, was carried out under batch conditions at 0.5 vvm aeration rate. Digestions were carried out at temperatures of 45, 50, 55, 60 and 65 °C (or left unregulated) without pH control to study the effect of digestion temperatures on TAD. The effects of digestion pH on the process were studied at pH 6.0, 7.0, 8.0, 9.0 and 9.5 (and in unregulated control) all at 55 °C. Except for digestion at 65 °C, which was inoculated extraneously using culture of Bacillus strearothermophilus all reactions were carried out using the populations indigenous to the waste. During digestion at different temperatures, the removal of soluble COD increased with temperature to reach a peak at 60 °C before declining slightly, removal of soluble solid (SS) followed similar pattern and reached peak at 65 °C being the highest temperature studied, while the degradation of TSS and TS (TSS+TS) decreased with an increase in temperature. Digestion at pH 7.0 was more efficient than at other pH values. Acetate was the predominant volatile fatty acid (VFA) in all the reactions and accounted for up to 90% of the total. Digestion at 60 °C led to the greatest accumulation of acetate, and this coincided with the period of highest oxygen uptake, and rapid consumption of soluble carbohydrate. Iso-valerate was also produced at all pH values. Digestion at 55 °C and also at pH 7.0 led to rapid and efficient processes with least accumulation of VFA and should be of interest in full-scale processes whenever it is practicable to regulate the digestion pH and temperature. The result of digestion at unregulated pH indicates that gradual adaptation may be used to achieve efficient treatment at elevated pH values. This would be of interest in full-scale processes where it is not practicable to tightly regulate digestion pH, and where the waste is produced at a pH value much higher than neutral. [Copyright &y& Elsevier]

The principal aim of this research was to evaluate the ability of different Yarrowia lipolytica strains, having different origin, to grow in olive mill wastewater (OMW) and reduce its COD level. All the strains were able to grow in undiluted OMW; the comparison between the data obtained in a semi-synthetic medium and in OMW suggests that lipases with different specificity can be produced in relation to the medium composition.Under the adopted conditions, the reduction of the OMW COD values varied from 1.47% and 41.22% of the initial value. Some strains determined a significant reduction of polyphenol content, while other ones caused its apparent increase. Moreover, some Y. lipolytica strains, isolated from chilled foods, produced the highest citric acid concentrations. These results evidenced that some Y. lipolytica strains are good candidates for the reduction of the pollution potential of OMW and for the production of enzymes and metabolites such as lipase and citric acid. [Copyright &y& Elsevier]

Studies were carried out on the treatment of wastewater from a bulk drug industry using an anaerobic fixed film reactor (AFFR) designed and fabricated in the laboratory. The chemical oxygen demand (COD) and total dissolved solids (TDS) of the wastewater were found to be very high with low biochemical oxygen demand (BOD) to COD ratio and high total suspended solid (TSS) concentration. Acclimatization of seed consortia and startup of the reactor was carried out by directly using the wastewater, which resulted in reducing the period of startup to 30 days. The reactor was studied at different organic loading rates (OLR) and it was found that the optimum OLR was 10 kg COD/m3/day. The wastewater under investigation, which had a considerable quantity of SS, was treated anaerobically without any pretreatment. COD and BOD of the reactor outlet wastewater were monitored and at steady state and optimum OLR 60–70% of COD and 80–90% of BOD were removed. The reactor was subjected to organic shock loads at two different OLR and the reaction could withstand the shocks and performance could be restored to normalcy at that OLR. The results obtained indicated that AFFR could be used efficiently for the treatment of wastewater from a bulk drug industry having high COD, TDS and TSS. [Copyright &y& Elsevier]

The objectives of the study were: (i) to examine the efficiency of nutrient removal during the treatment of dairy farm effluent in a two-pond system, and (ii) to produce an inexpensive but effective nutrient trap which could be recycled as a nutrient source or soil mulch. The concentration of chemical oxygen demand (COD), biological oxygen demand (BOD), nitrogen (N), phosphorus (P) and potassium (K) in a two-pond system used to treat dairy farm effluent was monitored over a period of 7 months. The retention of nutrients by two porous materials was examined both in the laboratory batch (zeolite and bark) and pilot-scale field (bark) experiments. The results indicated that biological treatment of farm effluents using the two-pond system was not effective in the removal of nutrients, which are likely to become pollutant when discharged to waterways. Both the bark and zeolite materials were effective in the removal of N, P and K from effluent. These materials can be placed in the second (i.e., aerobic) pond to treat effluents, which can then be discharged to streams with minimum impact on water quality. The nutrient-enriched porous materials can be recycled as a source of nutrients and soil conditioner. [Copyright &y& Elsevier]

Potato chips industry wastewater was collected and analyzed for biochemical oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids (TSS) and total carbohydrates. Two Aspergillus species, A. foetidus and A. niger, were evaluated for their ability to grow and produce biomass and reduce the organic load of the wastewater. A. foetidus MTCC 508 and A. niger ITCC 2012 were able to reduce COD by about 60% and produce biomass 2.4 and 2.85 g l−1, respectively. Co-inoculation of both Aspergillus strains resulted in increased fungal biomass production and higher COD reduction than in individual culture at different culture pH. pH 6 was optimum for biomass production and COD reduction. Amendment of the wastewater with different N and P sources, increased the biomass production and COD reduction substantially. Under standardized conditions of pH 6 and amendment of wastewater with 0.1% KH2PO4 and 0.1% (NH4)2SO4, a mixed culture gave 90% reduction in COD within 60 h of incubation. [Copyright &y& Elsevier]

Studies are carried out on the treatment of wastewater from a bulk drug industry using an anaerobic fixed film reactor (AFFR) designed and fabricated in the laboratory. The chemical oxygen demand (COD) and total dissolved solids (TDS) of the wastewater are found to be very high with low Biochemical oxygen demand (BOD) to COD ratio and high total suspended solid (TSS) concentration. Acclimatization of seed consortia and start up of the reactor is carried out by directly using the wastewater, which resulted in reducing the period of startup to 30 days. The reactor is studied at different organic loading rates (OLR) and it is found that the optimum OLR is 10 kg COD/m3/day. The wastewater under investigation, which is having considerable quantity of SS, is treated anaerobically without any pretreatment. The COD and BOD of the reactor outlet wastewater are monitored and reduction at steady state and optimum OLR is observed to be 60–70% of COD and 80–90% of BOD. The reactor is subjected to organic shock loads at two different OLR and it is observed that the reactor could withstand shocks and performance could be restored to normalcy at that OLR. The results obtained indicated that AFFR could be used efficiently for the treatment of wastewater from a bulk drug industry having high COD, TDS and TSS. [Copyright &y& Elsevier]

Biohydrogen production by anaerobic microbes enriched from heat-shocked cow dung compost was studied by using an artificial medium containing sucrose. Initial pH and substrate levels were selected as target factors in this study. Our experimental results demonstrated that optimal substrate concentration and pH for the composts generating hydrogen gas were 4.0 ± 0.5 g sucrose/l and 5.4 ± 0.2, respectively. Supplementary experiments confirmed that chemical oxygen demand reduction efficiency (69%) obtained from the conditions of sucrose=4.0 g/l and pH=5.5 was significantly greater than that (37%) from sucrose=5.0 g/l and pH=5.0. Experimental results of metabolites analysis led us to the conclusion that Clostridium sp. predominated in the anaerobic composts, suggesting that inocula used to seed the batch experiment can be obtained from a common natural source. [Copyright &y& Elsevier]

This research evaluated utilization of organic compounds and biomass accumulation in three different layered sand filter biofilm systems renovating a mixture of detergent and milk fat. Organic compounds were measured as chemical oxygen demand (COD) and biomass as ATP. A two-layer sand filter with coarse sand on the top and fine sand at the bottom; a three-layer sand filter with pea gravel on the top, coarse sand in the middle, and fine sand at the bottom; and a two-filters in-series sand filter biofilm system each received mixtures of butterfat and detergent. While the three-layer sand filter system had greater COD utilization capacity due to a longer filter run, the two-filters in-series sand filter system had greater COD utilization efficiency. The COD utilization was highly associated with the period of filter run to clogging. The decrease of COD utilization rate could lead to the clogging of sand filters. To maintain long filter runs without clogging, a COD loading rate of 2100 mg O2/m2/h was recommended for three-layer sand filters and 1800 mg O2/m2/h for two-layer sand filters for high fat content wastewater. In the two-layer sand filters and the three-layer sand filters, biomass did not seem to accumulate in any particular layer on a unit volume of sand. However, based on unit surface area, the coarse sand layer accumulated more biomass than the fine sand layer and the pea gravel layer. [Copyright &y& Elsevier]

Two horizontal subsurface flow reed beds of 75 m2 each, treating dairy parlor effluent and domestic sewage (about 6.5 m3/day), were set-up to determine the efficiency of this system in reducing the polluting load in an isolated mountain rural settlement.A total suspended solids value of about 0.70 g/l and chemical oxygen demand (COD) and biological oxygen demand (BOD5) values of about 1200 and 450 mg/l O2, respectively, were characteristic of the influent waters. Removal of suspended solids and organic load constantly remained at levels above 90%, while those of the nutrients N and P were about 50% and 60%, respectively. The total number of coliform bacteria and Escherichia coli was reduced by more than 99%, and faecal streptococci by more than 98%. Nitrates, chlorides, sulfates, anionic and non-ionic surface-active agents and heavy metals were detected only in low concentrations. Concentration and localization of metals was also quantified in Phragmites tissues by microanalysis.Results demonstrated the use of reed beds as an appropriate treatment to reduce pollutants in wastewater from rural activities to values acceptable for discharge into surface waters. [Copyright &y& Elsevier]

The XOAZRP TCF sequence was applied to bleach wheat straw pulp. Following each bleaching stage, the properties of the pulp (viz. kappa number, standard viscosity, borohydride viscosity and brightness) and of the resulting effluents were determined. The performance of the reagents was analyzed through the studies of xylanase treatment and crystallinity and scanning electron microscopy of the pulps. Finally, the pulp was refined at 1000 revolutions in a PFI mill and the mechanical properties of the resulting paper were determined and compared with those of paper from a eucalyptus pulp. Despite its shortcomings, wheat straw pulp can be effectively bleached with the proposed TCF sequence. [Copyright &y& Elsevier]

• The microbial community in wastewater play an important role in current generation. • The presence of aerobic bacteria in the sample reduces the current generation. • The anode needs to be cultured by the same source of water a prior measurement. • Pretreatment of bacteria before testing may improve the accuracy and reliability. • Two ways to reduce the systemic error in testing wastewater were firstly proposed. Microbial fuel cells (MFCs) based sensors had been studied in measuring biochemical oxygen demand (BOD) or the equivalent chemical oxygen demand (COD) recently. Limited attention has been paid to the effect of the microbial communities in wastewater on the responses of these sensors. This study systematically evaluated, for the first time, the effect of wastewater samples from a variety of sources on the electrical response of a micro-fabricated double-chamber MFC device. It was found that the response of the MFC is positively correlated with the bacterial composition, in particular electroactive bacteria. The presence of aerobic bacteria in the sample reduces the current generation. These findings indicated that the bacterial content of the water sample could be a significant interference source and must be considered in the use of µMFC-based sensors. Filtering samples may be effective in improving the reliability of these microsensors. [ABSTRACT FROM AUTHOR]

A fixed film bioreactor for the denitrification of the effluent from an anaerobic membrane bioreactor (AnMBR) treating domestic wastewater was designed, built and investigated. After anaerobic treatment, the wastewater usually has a low C/N ratio (∼1.3), and a remaining chemical oxygen demand of around 117mg O 2 /L, which is not enough to make conventional heterotrophic denitrification possible. That effluent also holds methane and sulfide dissolved and oversaturated after leaving the AnMBR. This paper demonstrates the feasibility of using these reduced compounds as electron donors in order to remove 80mg NO x - -N/L at 18°C and 2h of hydraulic retention time. In addition, the influence of the NO 2 - /NO 3 - ratios in the feed was studied. Total nitrogen removal was achieved in all the cases studied, except for a feed with 100% NO 3 - . Methane was the main electron donor used to remove the nitrites and nitrates, with a participation rate of over 70%., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

The primary aim of the study was to develop and validate an in-house upscale of Automatic Methane Potential Test System II for studying real-time inocula and real-scale substrates in batch, codigestion and enzyme enhanced hydrolysis experiments, in addition to semi-continuous operation of the developed equipment and experiments testing inoculum functional quality. The successful upscale to 5L enabled comparison of different process configurations in shorter preparation times with acceptable accuracy and high-through put intended for industrial decision making. The adoption of the same scales, equipment and methodologies in batch and semi-continuous tests mirroring those at full scale biogas plants resulted in matching methane yields between the two laboratory tests and full-scale, confirming thus the increased decision making value of the approach for industrial operations., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Lab-scale experiments were conducted to investigate the aerobic granular sludge process for simultaneous phosphorus (P) accumulation by chemical precipitation and biological nitrogen removal via nitrite. The P-rich granules were successfully incubated in a sequencing batch reactor, in which simultaneous nitrification-denitrification occurred via nitrite. The average diameter of the P-rich granules was 2.47 mm and the P content in granules was much higher than that in other granular systems with enhanced biological phosphorus removal process. Filamentous bacteria (genus Thiothrix) in the granules and the long sludge retention time (30 d) of the granular system played a crucial role in accumulation of precipitated phosphate. X-ray diffraction analysis, scanning electron microscopy coupled with energy dispersive X-ray and the experimental design using response surface methodology confirmed that the main mineral patterns in P-rich granules were Ca-Mg phosphate and whitlockite., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Twelve European habitat types were investigated to determine the influence of the IFBB technique (integrated generation of biogas and solid fuel from biomass) on the fate of organic compounds and energy yields of semi-natural grassland biomass. Concentration of organic compounds in silage and IFBB press cake (PC), mass flows within that system and methane yields of IFBB press fluids (PF) were determined. The gross energy yield of the IFBB technique was calculated in comparison to hay combustion (HC) and whole crop digestion (WCD). The IFBB treatment increased fibre and organic matter (OM) concentrations and lowered non-fibre carbohydrates and crude protein concentrations. The PF was highly digestible irrespective of habitat types, showing mean methane yields between 312.1 and 405.0 LN CH4 kg(-1) VS. Gross energy yields for the IFBB system (9.75-30.19MWh ha(-1)) were in the range of HC, outperformed WCD and were influenced by the habitat type., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

An anoxic biocathode was developed using sulfate-reducing bacteria (SRB) consortium on activated carbon fabric (ACF) and the effect of stainless steel (SS) mesh as additional current collector was investigated. Improved performance of biocathode was observed with SS mesh leading to nearly five folds increase in power density (from 4.79 to 23.11 mW/m(2)) and threefolds increase in current density (from 75 to 250 mA/m(2)). Enhanced redox currents and lower Tafel slopes observed from cyclic voltammograms of ACF with SS mesh indicated the positive role of uniform electron collecting points. Differential pulse voltammetry technique was employed as an additional tool to assess the redox carriers involved in bioelectrochemical reactions. SRB biocathode was also tested for reduction of volatile fatty acids (VFA) present in the fermentation effluent stream and the results indicated the possibility of integration of this system with anaerobic fermentation for efficient product recovery., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

A general methodology to implement fermentable soluble substrates in the IWA Anaerobic Digestion Model No. 1 (ADM1) that extends its application to anaerobic co-digestion of multiple substrates is presented. The approach considers the fermentation of new soluble substrates, not originally described in ADM1, as channelled through mass- and electron-balanced sugar fermentation equivalent reactions, and that fermentable substrates are degraded by a generic group of fermenters instead of the original ADM1 sugar fermenters. Therefore, no additional microbial group state is required. An additional term that modifies the ADM1 sugar fermentation kinetics equation was included to account for the competition among multiple substrates to be degraded by a particular biomass group. The model was validated at pilot scale treating a blend of pig manure (soluble fraction), wine and gelatine at mesophilic conditions. Only the ADM1 acetoclastic ammonia inhibition parameter was calibrated to obtain consistent model prediction of gas and liquid composition., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Twelve hydrothermal pre-treatment combinations of temperature (150 and 180 °C), time (10 and 20 min) and acid catalyst (no catalyst; H2SO4 at 2% w/w immediately before steam cooking or in 24-h pre-soaking) were tested to assess their effects on methane yield of Giant reed biomass vs. untreated control. A batch anaerobic digestion was conducted with 4 g VS l(-1) at 53 °C for 39 days. Untreated biomass exhibited a potential CH4 yield of 273 ml g(-1) VS; the four pre-treatments without acid catalyst achieved a 10%, 7%, 23% and 4% yield gain in the respective temperature/time combinations 150 °C/10 min, 150 °C/20 min, 180 °C/10 min and 180 °C/20 min. Conversely, the eight pre-treatments with H2SO4 catalyst incurred a methanogenic inhibition in association with high SO4(2-) concentration in the hydrolysate, known to enhance sulphate reducing bacteria. Furfurals were also detected in the hydrolysate of five strong pre-treatments with H2SO4 catalyst., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

This study investigated the effects of substrate composition (acetate and propionate) on synthesis of various mix of poly(hydroxybutyrate-hydroxyvalerate) (P(HB/HV)) from activated sludge, which was acclimated using a single carbon (acetate) and mixed carbons (acetate and propionate). Results of batch P(HB/HV) production tests indicated that the yield and synthesis rate of P(HB/HV) decreased as the proportion of propionate in the substrate increased. However, mixed-carbon-acclimated sludge with acetate and propionate exhibited better P(HB/HV) production performance than with acetate-acclimated sludge in terms of substrate utilization, yield of P(HB/HV) and HV fraction in P(HB/HV). The desired hydroxyvalerate (HV) fraction (0-74%) of the P(HB/HV) could be obtained based on the substrate composition and sludge acclimation. Furthermore, PCR-DGGE analysis indicated that specific species dominated the activated sludge used for P(HB/HV) production. Acidobacteria and Burkholderiales were the dominant bacterial populations and played an important role in HV synthesis., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

To investigate methanogenic community structure and process performance of anaerobic digestion treating swine wastewater at different scale, a pilot plant with 20 m(3) of effective working volume and lab scale methanogenic digester with 6L working volume were operated for 71 days and 6 turnover periods, respectively. During the steady state of anaerobic digestion, COD and VS removal efficiency in pilot plant were 65.3±3.2, 51.6±4.3%, respectively, which was similar to those in lab scale. However, calculated VFAs removal efficiency and methane yield were lower in pilot plant than in lab scale digester. Also, organics removal efficiencies, which consist of total carbohydrates, proteins, and lipids, were different between pilot and lab scale. These results were thought to be due to the ratio of carbohydrates to proteins in the raw swine wastewater. As a result of qualitative microbial analysis, Methanoculleus receptaculii, and Methanoculleus bourgensis, were commonly concerned with methane production., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

The newly isolated extreme thermophilic ethanologen Thermoanaerobacter pentosaceus was immobilized in different support materials in order to improve its ethanol production ability. In batch fermentation, a maximum ethanol yield of 1.36 mol mol(-1) consumed sugars was obtained by T. pentosaceus immobilized on rapeseed straw. Additionally, immobilized T. pentosaceus' ethanol production was improved by 11% in comparison to free cells. In continuous mode, it was shown that hydraulic retention time (HRT) affected ethanol yield, and a dramatic shift from ethanol to acetate and lactate production occurred at an HRT of 6 h. The maximum ethanol yield and concentration, 1.50 mol mol(-1) consumed sugars and 12.4 g l(-1), were obtained with an HRT of 12 h. The latter represented an improvement of 60% in relation to previously obtained results. This indicates that immobilization of T. pentosaceus is an effective strategy to improve its ethanol production ability., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

A novel and robust distributed benthic microbial fuel cell (DBMFC) was developed to address the energy supply issues for oceanographic sensor network applications, especially under scouring and bioturbation by aquatic life. Multi-anode/cathode configuration was employed in the DBMFC system for enhanced robustness and stability in the harsh ocean environment. The results showed that the DBMFC system achieved peak power and current densities of 190mW/m(2) and 125mA/m(2) respectively. Stability characterization tests indicated the DBMFC with multiple anodes achieved higher power generation over the systems with single anode. A computational model that integrated physical, electrochemical and biological factors of MFCs was developed to validate the overall performance of the DBMFC system. The model simulation well corresponded with the experimental results, and confirmed the hypothesis that using a multi anode/cathode MFC configuration results in reliable and robust power generation., (Published by Elsevier Ltd.)