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Though aerobic composting has been frequently applied to kitchen waste disposal, appropriate bulking agents are essential to acquire a promising performance. Fallen leaves and tree pruning in urbans face huge disposal demands and have great potentials as bulking agents of aerobic composting while have been seldom examined yet. This study comparably explored the performance of fallen leaves bulked and tree pruning bulked aerobic composting disposing kitchen waste. Results indicated that though both reactors were effective in degrading kitchen waste, leaf bulked composting was superior to tree pruning bulked composting in terms of longer thermophilic period and higher maximum temperature, higher organics degradation efficiency, higher humification and less odorous gas emission. Bacterial community was a driving mechanism for above results. This study shows that fallen leaves bulked aerobic composting has great potentials for kitchen waste disposal.

A continuous-flow moving bed biofilm reactor (IAMBBR) alternating microaerobic and aerobic conditions was used to remove carbon, nitrogen and phosphorus through simultaneous nitrification and denitrification coupled to phosphorus removal (SNDPR). The IAMBBR was operated under different dissolved oxygen (DO) ranges (0.2–2, 0.2–3 and 0.2–4 mg L−1) and feed C/N ratios (2.8, 3.6 and 4.2) at HRT of 1 day. At a DO range of 0.2–3 mg L−1 and feed C/N ratio of 3.6, the IAMBBR achieved simultaneous removal of dissolved organic carbon (DOC), total inorganic nitrogen (TIN) and P-PO43− with average efficiencies of 100%, 62% and 75%, respectively. Illumina sequencing revealed the coexistence of nitrifiers and P-accumulating denitrifiers (e.g. Hydrogenophaga) in the IAMBBR biofilm. Batch activity tests showed that phosphorus uptake did not occur under stable anaerobic or anoxic conditions, nor under aerobic conditions in absence of nitrate.

Substrate selection is one of the key technical issues for constructed wetlands (CWs), which works for wastewater treatment based mainly on the biofilm principle. In recent years, many alternative substrates have been studied and applied in CWs, and a review is conducive to providing updated information on CW R&D. Based on the intensive research work especially over the last 10 years on the development of emerged substrates (except for the three conventional substrates of soil, sand, and gravel) in CWs, this review was made. The substrates are categorized depending on their main roles in pollutant removal as ion-exchange substrates, P-sorption substrates, and electron donor substrates. Among these, reuse of various waste products as substrates was suggested due to their competitive pollutant removal efficiency and minimized waste disposal. Regarding substrate development, future research on avoiding substrate clogging to extend their lifetime in CWs is needed.

The biofilm system is beneficial for Anammox process designed to treat landfill leachate. In this study, the composition of extracellular polymeric substances (EPS) and the microbial community in an Anammox biofilm system were analyzed to determine the functions driving the biofilm's ability to treat landfill leachate. The results demonstrated that increasing influent carbon oxygen demand (COD) could stimulate EPS production. EPS helped enrich Anammox bacteria and supplied them with nutrients and enzymes, facilitating effective nitrogen removal (approximately 95%). The variation in Anammox bacteria was similar to the variation in EPS composition. In the tested Anammox Sequencing Biofilm Batch Reactor (SBBR) system, Candidatus Kuenenia was dominant among known Anammox genus, because of its high substrate affinity and because it adapts better to landfill leachate. The relative abundance of Candidatus Kuenenia in the biofilm rose from 3.26% to 12.38%, illustrating the protection and enrichment offered by the biofilm in carrying out Anammox.

Anaerobic digestion has been practically applied in agricultural and industrial waste treatment and recognized as an economical-effective way for food waste disposal. This paper presented an overview on the researches about anaerobic digestion of food waste. Technologies (e.g., pretreatment, co-digestion, inhibition and mitigation, anaerobic digestion systems, etc.) were introduced and evaluated on the basis of bibliometric analysis. Results indicated that ethanol and aerobic prefermentation were novel approaches to enhance substrates hydrolysis and methane yield. With the promotion of resource recovery, more attention should be paid to biorefinery technologies which can produce more useful products toward zero emissions. Furthermore, a technological route for food waste conversion based on anaerobic digestion was proposed.

Recently, efficient disposal of food waste (FW) with potential resource recovery has attracted great attentions. Due to its easily biodegradable nature, rich nutrient availability and high moisture content, FW is regarded as favorable substrate for anaerobic digestion (AD). Both waste disposal and energy recovery can be fulfilled during AD of FW. Volatile fatty acids (VFAs) which are the products of the first-two stages of AD, are widely applied in chemical industry as platform chemicals recently. Concentration and distribution of VFAs is the result of acidogenic metabolic pathways, which can be affected by the micro-environment (e.g. pH) in the digester. Hence, the clear elucidation of the acidogenic metabolic pathways is essential for optimization of acidogenic process for efficient product recovery. This review summarizes major acidogenic metabolic pathways and regulating strategies for enhancing VFAs recovery during acidogenic fermentation of FW.

Anaerobic digestion (AD) of food waste is widely accepted as a promising technology for both waste disposal and resource recovery. With the advancing of AD technology, to exploit the capacity of organic waste for maximum energy/resource recovery becomes the new focus and hence, improve the viability of this technology for practical application. Product inhibition and mass transfer are the common limitations encountered during AD of putrescible organic waste. Biochar materials have been widely used to promote AD process in recent years. This review summarizes the mechanism and regulation strategies of biochar and its modified derivatives in promoting AD of solid waste (mainly food waste) from the three aspects of hydrolysis, syntrophic acetogenesis, and methane production. At the same time, the relationship between carbon materials and electron transfer among anaerobic microbes is summarized from the perspective of microbial community. In addition, the market application of this technology was evaluated.

This study investigated the feasibility of coupling simultaneous partial nitrification and denitrification (SPND) to biological phosphorus removal in continuous-flow intermittently-aerated moving bed biofilm reactors (MBBRs) fed with different carbon sources, i.e. ethanol and acetate. Bacterial cultivation at pH 8.2 (±0.2), 26–28 °C and SRT of 4 day and microaerobic/aerobic MBBR operation allowed to achieve average dissolved organic carbon (DOC), total inorganic nitrogen (TIN) and P-PO43− removal efficiencies (REs) of 100%, 81–88% and 83–86% at HRT of 1 day, dissolved oxygen (DO) range of 0.2–3 mg L−1 and feed C/N and C/P ratios of 3.6 and 11, respectively. Acetate supplementation favored a diversified microbial community, while overgrowth of heterotrophs was observed when increasing feed C/N ratio in ethanol-fed MBBR. Illumina sequencing displayed the presence of putative phosphorus accumulating organisms (PAOs) such as Hydrogenophaga and Pseudomonas in MBBR biofilm and suspended biomass, whereas no typical NOB was identified during the study.

This paper aims to examine the potential of waste biorefineries in developing countries as a solution to current waste disposal problems and as facilities to produce fuels, power, heat, and value-added products. The waste in developing countries represents a significant source of biomass, recycled materials, chemicals, energy, and revenue if wisely managed and used as a potential feedstock in various biorefinery technologies such as fermentation, anaerobic digestion (AD), pyrolysis, incineration, and gasification. However, the selection or integration of biorefinery technologies in any developing country should be based on its waste characterization. Waste biorefineries if developed in developing countries could provide energy generation, land savings, new businesses and consequent job creation, savings of landfills costs, GHG emissions reduction, and savings of natural resources of land, soil, and groundwater. The challenges in route to successful implementation of biorefinery concept in the developing countries are also presented using life cycle assessment (LCA) studies.

The biodegradation of synthetic wastewater containing Atrazine, Malathion and Parathion was studied in two stage Integrated Aerobic Treatment Plant using Bacillus sp. (consortia) isolated from agricultural field. The influent stream containing these pesticides with initial COD of 1232mg/L were fed to first reactor and treated effluent of first reactor was fed to second reactor. The maximum removal of pesticides in IATP was found to be greater than 90%. The various process parameters such as pH, DO, Redox potential and BOD5/COD were monitored during the treatment. The degradation of pesticides and its metabolites in the treated effluent were confirmed by GC-MS. Kinetic parameters such as first order rate constant (Kobs), cell yield (YX/C) and decay coefficients (Kdp) were evaluated and found to be 0.00425 per hr, 0.696mg of COD/mg MLSS and 0.0010 per hr respectively. This integrated process was found more effective than physico-chemical treatment of pesticides.

Concerns over increasing amounts of sewage sludge and unsustainability of current disposal methods have led to development of alternative routes for sludge management. The large amount of organics in sewage sludge makes it potential feedstock for energy or fuel production via thermochemical pathways. In this study, ex-situ catalytic pyrolysis using HZSM-5 catalyst was explored for the production of olefinic and aromatic hydrocarbons and nutrient-rich char from sewage sludge. The optimal pyrolysis and catalysis temperatures were found to be 500°C and 600°C, respectively. Carbon yields of hydrocarbons from sewage sludge were higher than for lignocellulose; yield differences were attributed to the high extractives content in the sludge. Full recovery of most inorganic elements were found in the char, which suggests that catalyst deactivation maybe alleviated through ex-situ catalytic pyrolysis. Most of the nitrogen was retained in the char while 31.80% was released as ammonia, which suggests a potential for nitrogen recycling.

Vermicomposting of paper mill sludge (PMS) and tea waste (TW) using cow dung (CD) in five different combinations was carried out using Eisenia fetida. The aim of this study was to manage the waste disposal problem of PMS using the environment-friendly technology of vermiconversion. The changes in physico-chemical parameters were observed at 30-day intervals up to 90 days. The final pH was within 6.09–6.95 among all units. The TN, TP and TK contents increased 0.30–0.87, 0.53–3.23, 0.33–0.63 times, respectively in all mixtures after vermicomposting with increase in EC and ash Content. Maximum reduction in Total Organic Carbon (23.91%) was observed in treatment with highest PMS content, attributed to earthworm activity. Reduction in C: N ratio (38.63%–54.05%) was significantly observed in all the treatments. It was finally inferred that the paper mill sludge and tea waste in combination with cow dung can be successfully biotransformed into useful manure employing earthworms.

Research insight into the technical challenges of bioplastics production has revealed their confoundedness in their niche markets and struggles to enter the mainstream. There is an increasing problem of waste disposal and high cost of pure substrates in polyhydroxyalkanoates (PHA) production. This has led to the future need of upgrading the waste streams from different industries into the role of feedstocks for production of PHA. The review covers the latest developments in using wastes and surplus materials for PHA production. In addition to inexpensive carbon sources, efficient upstream and downstream processes and recycling of waste streams within the process are required to maintain the circularity in the entire process. A view on the link between circular bioeconomy and PHA production process covering the techno-economic, life cycle assessment and environmental aspects has also been provided. Furthermore, the future perspectives related to the topic have also been discussed.

In this study, the disintegration potential of disperser coupled rhamnolipid (RLD) was investigated on pulp and paper mill secondary sedimentation tank (PPST) sludge. Initially, RLD dosage and pH were optimized for liquefied organic content release. Maximal of liquefied organic content release of 2158 mg/L was attained at an optimized RLD dosage (0.009 g/g TS (Total solids), pH 10). To augment liquefaction of PPST sludge further, disperser and disperser coupled RLD methods were carried out. Disperser coupled RLD method has achieved maximal liquefaction rate (27%) and total suspended solids (TSS) reduction (20%) at 5128 kJ/kg TS when compared to disperser method. Subsequently, methane assay was performed in which disperser coupled RLD method yielded higher methane production of 295 mL/g VS (Volatile solids). Then, cost analysis was performed in which disperser coupled RLD method achieved a net profit of 134 $/ ton of PPST sludge.

Petroleum industry is one of the largest and fast growing industries due to the ever increasing global energy demands. Petroleum refinery produces huge quantities of wastes like oily sludge, wastewater, volatile organic compounds, waste catalyst, heavy metals, etc., because of its high capacity and continuous operation of many units. Major challenge to this industry is to manage the huge quantities of waste generated from different processes due to the complexity of waste as well as changing stringent environmental regulations. To decrease the energy loss for treatment and also to conserve the energy stored in the chemical bonds of these waste organics, bio-electrochemical system (BES) may be an efficient tool that reduce the economics of waste disposal by transforming the waste into energy pool. The present review discusses about the feasibility of using BES as a potential option for harnessing energy from different waste generated from petroleum refineries.

The single cell oil (SCO) production by the mono and mixed culture of microalgae Chlorella pyrenoidosa and red yeast Rhodotorula glutinis was investigated using non-detoxified cassava bagasse hydrolysate (CBH) as carbon source. The results suggested that the two strains were able to tolerate and even degrade some byproducts presented in the CBH, and the mixed culture approach enhanced the degradation of certain byproducts. Biomass (20.37 ± 0.38 g/L) and lipid yield (10.42 ± 1.21 g/L) of the mixed culture achieved in the batch culture were significantly higher than that of the mono-cultures (p 0.05). The fed-batch culture further raised the biomass and lipid yield to 31.45 ± 4.93 g/L and 18.47 ± 3.25 g/L, respectively. The lipids mainly composed of oleic acid and palmitic acid, suggesting the potential applications such as biofuel feedstock, cosmetics, food additives and lubricant. This study provided new insights for the integration of the economical SCO production with agro-industrial waste disposal.

The environmental sustainability of aquaculture wastewater treatment by microalgal bacterial flocs (MaB-flocs) in an outdoor raceway pond was analyzed using life cycle assessment. Pikeperch aquaculture wastewater treated at pilot scale (Belgium; 28 m 2 ) and industrial scale (hypothetical up-scaling; 41 ponds of 245 m 2 ) were compared. The integration of the MaB-floc raceway pond in a broader aquaculture waste treatment system was studied, comparing the valorisation of MaB-flocs as shrimp feed and as biogas. Up-scaling improves the resource footprint of the plant (848 MJ ex,CEENE kg −1 MaB-floc TSS at pilot scale and 277 MJ ex,CEENE kg −1 MaB-floc TSS at industrial scale) as well as its carbon footprint and eutrophication potential. At industrial scale, the valorisation of MaB-flocs as shrimp feed is overall more sustainable than as biogas but improvements should be made to reduce the energy use of the MaB-floc raceway pond, especially by improving the energy-efficiency of the pond stirring system.

For the purpose of safe disposal of biomass contaminated by biosorption of heavy metals, phosphate-assisted pyrolysis of water hyacinth biomass contaminated by lead (Pb) was tried to reduce the bioavailability and leaching potential of Pb, using direct pyrolysis without additive as a control method. Direct pyrolysis of the contaminated biomass at low temperatures (300 and 400°C) could reduce the bioavailability of Pb, but the leaching potential of Pb was increased with the rising pyrolysis temperature. While phosphate-assisted pyrolysis significantly enhanced the recovery and stability of Pb in the char. Specifically, the percentages of bioavailable Pb and leachable Pb in the chars obtained by phosphate-assisted pyrolysis at low temperatures were reduced to less than 5% and 7%, respectively. The sequential extraction test indicated the transformation of Pb into more stable fractions after phosphate-assisted pyrolysis, which was related to the formation of Pb phosphate minerals including pyromorphite and lead-substituted hydroxyapatite.

The purpose of this paper is to develop a model for designing the most sustainable bioethanol supply chain. Taking into consideration of the possibility of multiple-feedstock, multiple transportation modes, multiple alternative technologies, multiple transport patterns and multiple waste disposal manners in bioethanol systems, this study developed a model for designing the most sustainable bioethanol supply chain by minimizing the total ecological footprint under some prerequisite constraints including satisfying the goal of the stakeholders’, the limitation of resources and energy, the capacity of warehouses, the market demand and some technological constraints. And an illustrative case of multiple-feedstock bioethanol system has been studied by the proposed method, and a global best solution by which the total ecological footprint is the minimal has been obtained.

The mechanisms of carbon and nutrient removal in an open algal-bacterial biofilm reactor and an open bacterial biofilm reactor were comparatively evaluated during the treatment of centrates and domestic wastewater. Comparable carbon removals (>80%) were recorded in both bioreactors, despite the algal-bacterial biofilm supported twice higher nutrient removals than the bacterial biofilm. The main carbon and nitrogen removal mechanisms in the algal-bacterial photobioreactor were assimilation into algal biomass and stripping, while stripping accounted for most carbon and nitrogen removal in the bacterial biofilm. Phosphorus was removed by assimilation into algal-bacterial biomass while no effective phosphorous removal was observed in the bacterial biofilm. Carbon, nitrogen and phosphorus removals of 91 ± 3%, 70 ± 8% and 85 ± 9%, respectively, were recorded in the algal-bacterial bioreactor at 10d of hydraulic retention time when treating domestic wastewater. However, the high water footprint recorded (0.5-6.7 Lm(-2)d(-1)) could eventually compromise the environmental sustainability of this microalgae-based technology.

A novel composite hollow fiber membrane for membrane aerated biofilm rector (MABR) was prepared by coating L-3,4-dihydroxyphenylalanine (DOPA) on the surface of PVDF membrane. MABR process study was conducted to test the performances of the original and modified membranes for 166 days. The results indicate that coated membrane showed 2 times higher gas flux, lower water contact angle (declined from 86.5° to 52°), and significantly improved surface roughness. The modified membrane displayed an excellent MABR performance. Its COD, NH4(+)-N and TN removal efficiencies were kept above 90%, 98.8% and 84.2% during the first 4-month experiment. By tracking experiment at 0.01 MPa, to achieve COD removal efficiency of 85.9%, half an hour is required with the modified membrane, instead of 6h using the original one. Besides, faster NH4(+)-N and TN removal at 0.01 MPa were also achieved with DOPA composite membrane.

This study investigated the diversity and abundance of AOA and AOB amoA genes in eight full-scale wastewater treatment plants (WWTPs). Although the process principles and system operations of the eight WWTPs were different, quantitative real-time PCR measurements showed that AOB amoA genes outnumbered AOA amoA genes with the ratio varying from 2.56 to 2.41×10(3), and ammonia may be partially oxidized by AOA. Phylogenetic analyses based on cloning and sequencing showed that Nitrososphaera cluster was the most dominant AOA species and might be distributed worldwide, and Nitrosopumilis cluster was few. Statistical analysis indicated that there might be versatile AOA ecotypes and some AOA might be not obligate autotrophic. The Nitrosomonas europaea cluster and Nitrosomonas oligotropha cluster were the two most dominant AOB species, and AOB species showed higher diversity than AOA species.

This investigation deals with the conversion of olive-mill wastewater (OMW) into several feedstocks suitable for hydrogen photo-production. The goal was reached by means of two sequential steps: (i) a pre-treatment process of stored-OMW for the removal of polyphenols, which made it possible to obtain several effluents, and (ii) a photo-fermentative process for hydrogen production by means of Rhodopseudomonas palustris sp. Four different adsorbent matrices (Azolla, granular active carbon, resin, and zeolite) were used to dephenolize stored-OMW. The four liquid fractions attained by using the above process created the same number of effluents, and these were diluted with water and then used for hydrogen photo-production. The maximum hydrogen production rate (14.31 mL/L/h) was attained with the photo-fermenter containing 25% of the effluent, which came from the pre-treatment of stored-OMW using granular active carbon. Using the carbon effluent as feedstock, the greatest light conversion efficiency of 2.29% was achieved.

The Combined Activated Sludge-Anaerobic Digestion Model (CASADM) quantifies the effects of recycling anaerobic-digester (AD) sludge on the performance of a hybrid activated sludge (AS)-AD system. The model includes nitrification, denitrification, hydrolysis, fermentation, methanogenesis, and production/utilization of soluble microbial products and extracellular polymeric substances (EPS). A CASADM example shows that, while effluent COD and N are not changed much by hybrid operation, the hybrid system gives increased methane production in the AD and decreased sludge wasting, both caused mainly by a negative actual solids retention time in the hybrid AD. Increased retention of biomass and EPS allows for more hydrolysis and conversion to methane in the hybrid AD. However, fermenters and methanogens survive in the AS, allowing significant methane production in the settler and thickener of both systems, and AD sludge recycle makes methane formation greater in the hybrid system.

The purpose of this study was to investigate the potential of copper-iron bimetallic particles supported sulfate-reducing bacteria (SRB) in enhancing the reduction of Cu(2+) and Zn(2+) in effluent. The results showed that the copper-iron bimetallic particles can enhance Cu(2+) and Zn(2+) removal and the resistance of the sulfate-reducing bacteria towards metals toxicity, the inhibiting concentration of Cu(2+) and Zn(2+) for SRB was significantly increased (from 100 to 200 mg/L for Cu(2+) and 300 to 400 mg/L for Zn(2+)). The removal efficiencies of Cu(2+) and Zn(2+) (initial concentration 100 mg/L) were 98.17% and 99.67% in SRB-Cu/Fe system after 48 h, while only 29.83% Cu(2+), 90.88% Zn(2+) and 63.81% Cu(2+), 72.63% Zn(2+) were removed in the SRB and Cu/Fe system at the same condition.

A continuous batch bioleaching was built to realize the bioleaching of sewage sludge in large scale. In the treatment, heavy metal in acid wastewater of bioleaching was removed by adsorption onto ramie residue. Then, acid wastewater was reused in next bioleaching batch. In this way, most time and water of bioleaching was saved and leaching efficiency of copper, lead and chromium kept at a high level in continuous batch bioleaching. It was found that residual heavy metal in sewage sludge is highly related to that in acid wastewater after bioleaching. To get a high leaching efficiency, concentration of heavy metal in acid wastewater should be low. Adsorption of copper from acid wastewater onto ramie residue can be described by pseudo first-order kinetics equation and Freundlich isotherm model. Trichoderma viride has the potential to be used for the concentration and recovery of heavy metal adsorbed onto ramie residue.

Over a 3 year period, interactions between nitrifying bacterial communities and the operational parameters of a full-scale wastewater treatment plant were analyzed to assess their impact on nitrification performance. Throughout the study period, nitrification fluctuated while Nitrosomonas europaea and Nitrosomonas nitrosa, the two major ammonia oxidizing bacteria (AOB) communities, showed resistance to changes in operational and environmental conditions. Nitrobacter populations mostly exceeded those of Nitrospira within nitrite oxidizing bacteria (NOB). Meanwhile, principal component analysis (PCA) results revealed that a close association between Nitrobacter and nitrite concentration as well as a direct correlation between the quantity of AOB and influent SCN- concentration. The serial shifts of data points over time showed that the nitrification of a full-scale treatment plant has been gradually suppressed by the influence of influent COD and phenol concentrations.

Pretreatments to sugarcane bagasse (SCB) such as CaCl2, alkali, ammonia, steam and milling showed 91%, 46%, 47%, 42% and 56% adsorption of Solvent Red 5B (SR5B); 92%, 57%, 58%, 56% and 68% adsorption of simulated dyes mixture (SDM), and 86%, 45%, 49%, 44% and 56% adsorption of a real textile effluent (RTE), respectively. However, the untreated SCB showed 32%, 38% and 30% adsorption of SR5B, SDM and RTE, respectively. Adsorption of SR5B on CaCl2 pretreated SCB follows pseudo-second order kinetics. SEM and FTIR analysis reveals the delignification of CaCl2 pretreated SCB. SR5B, SDM and RTE adsorbed on CaCl2, alkali, ammonia, steam and milling pretreated SCB were decolorized under solid state fermentation using isolated Providensia staurti strain EbtSPG. Tray bioreactor study showed 86% American Dye Manufacturers Institute (ADMI) removal of RTE in 72 h. Biodegradation of adsorbed SR5B was confirmed using FTIR, HPLC and HPTLC.

The present study relates to a nanotechnology enabled method in which purified laccase from Escherichia coli AKL2 was supplemented with 100 μM copper oxide nanoparticles (Cu(2)O) (NP-laccase). The activity, half life and stability of NP-laccase were enhanced by 4, 42 and 36-fold respectively at high temperature (80 °C) and also over a wide range of pH (4-12) than laccase (in the presence of 0.18 mM CuSO(4)). Thermodynamic analysis of the nanoparticle-induced enzyme stability revealed an enhanced entropy-enthalpy compensation at 80 °C, which reflected the maintenance of its native structure. This was further supported by CD studies. The enhanced activity and thermostability of NP-laccase can be utilized for efficient decolorisation of dyes (both phenolic and azo).

Acid-rich effluent generated from acidogenic biohydrogen production process was evaluated as substrate for lipid synthesis by integrating with heterotrophic cultivation of mixed microalgae. Experiments were performed both with synthetic volatile fatty acids (SVFA) and fermented fatty acids (FFA) from biohydrogen producing reactor. Fatty acid based platform evidenced significant influence on algal growth as well as lipid accumulation by the formation of triglycerides through fatty acid synthesis. Comparatively FFA documented higher biomass and lipid productivity (1.42mg/ml (wet weight); 26.4%) than SVFAs ((HAc+HBu+HPr), 0.60mg/ml; 23.1%). Lipid profiles varied with substrates and depicted 18 types of saturated and unsaturated fatty acids with wide fuel and food characteristics. The observed higher concentrations of Chl b over Chl a supports the biosynthesis of triacylglycerides. Microalgae diversity visualized the presence of lipid accumulating species viz., Scenedesmus sp. and Chlorella sp. Integration of microalgae cultivation with biohydrogen production showed lipid productivity for biodiesel production along with additional treatment.

Different types of carriers were tested as support material in a lab-scale moving bed biofilm reactor (MBBR) used to treat urban wastewater under three different conditions of hydraulic retention time (HRT) and carrier filling ratios (FR). The bacterial diversity developed on the biofilms responsible of the treatment was studied using a cultivation-independent approach based on the polymerase chain reaction-temperature gradient gel electrophoresis technique (PCR-TGGE). Cluster analysis of TGGE fingerprints showed significant differences of community structure dependent upon the different operational conditions applied. Redundancy analysis (RDA) was used to determine the relationship between the operational conditions (type of carrier, HRT, FR) and bacterial biofilm diversity, demonstrating a significant effect of FR=50%. Phylogenetic analysis of PCR-reamplified and sequenced TGGE bands revealed that the prevalent Bacteria populations in the biofilm were related to Betaproteobacteria (46%), Firmicutes (34%),Alphaproteobacteria (14%) and Gammaproteobacteria (9%).

The effect of salinity on the hydrolytic enzymatic activities (acid phosphatase, alkaline phosphatase, glucosidase, protease and esterase) released by the microorganisms in a submerged fixed bed bioreactor for real urban wastewater treatment was investigated. The influence of salt (NaCl) on the enzymatic activities was evaluated in four different experiments with concentrations of NaCl of 0, 3.7, 24.1 and 44.1g/L, remaining constant all other operating parameters of the bioreactor. The results show that enzymatic activities were reduced when the salinity was increased in the influent and consequently the biotransformation of organic matter in the submerged fixed bed bioreactor significantly decreased. A redundancy analysis was performed to evaluate the relationships between enzymatic activities and physic-chemical parameters analyzed in the influent. According to the results obtained with the Monte Carlo permutation test, salinity and sampling day significantly contributed to explain the variation of enzymatic activities, showing a negative correlation.

A small wastewater treatment plant (WWTP) failed to meet effluent requirements of the first-A discharge standard in China, with the anaerobic/anoxic/oxic (A/A/O) process treating municipal and partial industrial wastewater. Thus an A/O step feed process (Anoxic/oxic/anoxic/oxic/anoxic/oxic) with floating plastic carriers in aerobic units was proposed to improve nutrient removal within the existing WWTP. Four main reform strategies were applied: (1) the original influent was divided into three streams which led into corresponding anoxic units; (2) floating plastic carriers were placed in the second and third oxic units; (3) nitrified liquid recycling was omitted; (4) channel shapes and sizes were adjusted between adjacent units to prevent backflow. After these modifications were implemented, the total nitrogen and phosphorus concentrations in the effluent were reduced from 20.8 to 14.2 mg/L, and from 1.89 to 0.57 mg/L, respectively. Moreover, annual electricity consumption in the WWTP was reduced by 245 MW h as a result of these modifications.

In this study, 454-pyrosequencing technology was employed to investigate the microbial communities in 12 municipal wastewater treatment plants (WWPTs) with different treatment processes. In total, 202,968 effective sequences of the 16S rRNA gene were generated from 16 samples that widely represented the diversity of the microbial communities. While Proteobacteria was found to be the dominant phylum in some samples, in other samples it was Bacteroidetes. The Simpson's diversity index and evenness index were lowest in samples from membrane bioreactors (MBRs), possibly due to the long sludge retention time (SRT) and low food/microorganism ratio (F/M). For one WWTP which had two disparate treatment processes operating in parallel, the structures of microbial communities in the two systems were compared. The differences found between the two indicated that the treatment process likely had effects on the structure of microbial communities.

This communication presents an integrated approach to study the potential of Chlorella pyrenoidosa for treatment of dairy wastewater (DWW) and biofuel extraction. The experiment was set up in two steps. The step-1 of the experiment was designed for treatment of dairy wastewater. The physical and chemical parameters of wastewater quality such as nitrate, phosphate, chloride, fluoride, hardness, etc., were studied. The level of nitrate and phosphate known, agents of eutrophication in water bodies was reduced by 60% and 87% in influent, 49% and 83% in the effluent, respectively. The step-2 of the experiment was designed for biofuel extraction by harvesting the biomass (algal strain) grown in dairy waste water. The result of this study shows that algal strain C. pyrenoidosa is not only an agent for mitigation of pollutant load, but it can also be used as potential agent for biofuel production.

A novel integrated thermophilic submerged aerobic membrane bioreactor (TSAMBR) and electrochemical oxidation (EO) technology was developed for thermomechanical pulping pressate treatment with the aim of system closure. The TSAMBR was able to achieve a chemical oxygen demand (COD) removal efficiency of 88.6 ± 1.9-92.3 ± 0.7% under the organic loading rate of 2.76 ± 0.13-3.98 ± 0.23 kg COD/(m(3) d). An optimal hydraulic retention time (HRT) of 1.1 ± 0.1d was identified for COD removal. Cake formation was identified as the dominant mechanism of membrane fouling. The EO of the TSAMBR permeate was performed using a Ti/SnO(2)-Sb(2)O(5)-IrO(2) electrode. After 6-h EO, a complete decolourization was achieved and the COD removal efficiency was increased to 96.2 ± 1.2-98.2 ± 0.3%. The high-quality effluent produced by the TSAMBR-EO system can be reused as process water for system closure in pulp and paper mill.

The potential of Phragmites australis was evaluated for the removal of three veterinary drugs, enrofloxacin (ENR), ceftiofur (CEF) and tetracycline (TET), from aquatic mediums. Results showed that the plant promoted the removal of 94% and 75% of ENR and TET, respectively, from wastewater. Microbial abundance estimation revealed that microorganisms were not a major participant. Occurrence of drugs adsorption to plant roots was observed in small extension. Therefore, main mechanisms occurring were drug removal by plant uptake and/or degradation. Present results demonstrated the potential of P. australis-planted beds to be used for removal of pharmaceuticals from livestock and slaughterhouse industries wastewater.

Bio-sequestration of CO(2) through microalgae cultivation is considered as a viable option for biofuel production as well as CO(2) mitigation. Influence of CO(2) sparging period and interval was evaluated on the growth and lipid accumulation of microalgae cultivated in domestic wastewater under mixotrophic microenvironment. Process performance was assessed in two phases viz., growth (GP) and starvation phases (SP) each with 8 days of retention time. Experimental variations depicted marked influence on biomass growth and lipid accumulation of microalgae with the function of harvesting period. Sparging period of 120 s documented maximum biomass growth (GP, 3.4 mg/ml) and lipid productivity (SP, 27.3%) while in intervals, 4h (120 s) condition showed maximum biomass (3.2mg/ml) and lipid productivity (27.8%). Total chlorophyll components documented higher concentrations of Chl b supporting the observed higher lipid productivity. Fatty acid composition varied with the experimental variations and represented higher degree of saturation indicating their utility as biodiesel.

Biological hydrogen production presents a possible avenue for the large scale sustainable generation of hydrogen needed to fuel a future hydrogen economy. Amongst the possible approaches that are under active investigation and that will be briefly discussed; biophotolysis, photofermentation, microbial electrolysis, and dark fermentation, dark fermentation has the additional advantages of largely relying on already developed bioprocess technology and of potentially using various waste streams as feedstock. However, the major roadblock to developing a practical process has been the low yields, typically around 25%, well below those achievable for the production of other biofuels from the same feedstocks. Moreover, low yields also lead to the generation of side products whose large scale production would generate a waste disposal problem. Here recent attempts to overcome these barriers are reviewed and recent progress in efforts to increase hydrogen yields through physiological manipulation, metabolic engineering and the use of two-stage systems are described.

The impact of phenolic compounds (around 3.2 g/L) resulted in a completely failed performance in a mesophilic UASB reactor treating coal gasification wastewater. The recovery strategies, including extension of HRT, dilution, oxygen-limited aeration, and addition of powdered activated carbon were evaluated in batch tests, in order to obtain the most appropriate way for the quick recovery of the failed reactor performance. Results indicated that addition of powdered activated carbon and oxygen-limited aeration were the best recovery strategies in the batch tests. In the UASB reactor, addition of powdered activated carbon of 1 g/L shortened the recovery time from 25 to 9 days and oxygen-limited aeration of 0-0.5 mgO2/L reduced the recovery time to 17 days. Reduction of bioavailable concentration of phenolic compounds and recovery of sludge activity were the decisive factors for the recovery strategies to tackle the impact of phenolic compounds in anaerobic treatment of coal gasification wastewater.

Immobilization is a fundamental method to improve both enzyme activity and stability. In the present work, the process previously described for immobilizing laccase - an enzyme oxidizing phenolic compounds - onto fumed silica was optimized, in order to efficiently produce industrially relevant amounts of a nanobiocatalyst for biological micropollutant elimination, whilst saving 80% of surface modification agent (3-aminopropyl triethoxy silane) and 90% of cross-linker (glutaraldehyde). Minimized losses during preparation and favorable effects of immobilization yielded conjugates with drastically increased enzymatic activity (164% of invested activity). Long-term stability and activity regarding bisphenol A (2,2-bis(4-hydroxyphenyl)propane) removal of the synthesized biocatalyst were assessed under application-relevant conditions. With 81.1±0.4% residual activity after 7 days, stability of conjugates was drastically higher than of free laccase, which showed virtually no activity after 1.5 days. These results illustrate the huge potential of fumed silica nanoparticles/laccase-composites for innovative biological wastewater treatment.

This study focuses on the enhancement of aerobic granulation and biological nutrient removal maintenance treating domestic wastewater. Two sequencing batch reactors (SBRs) were inoculated with either only floccular sludge (100%-floc SBR) or supplemented with 10% crushed granules (90%-floc SBR). Granules developed in both reactors. The 100%-floc SBR achieved 75% of nitrogen and 93% of phosphorus removal at the end of the performance, but some floccular sludge remained in the system. The 90%-floc SBR became fully granulated and finished with 84% and 99% of nitrogen and phosphorus removal, respectively. Regarding biological phosphorus removal, nitrite was identified as an inhibitor of the process. Nitrite levels lower than 5 mg N-NO2-L(-1) were used for anoxic phosphate uptake while higher concentrations inhibited the process.

The functional role of aerobic and anoxic microenvironments on polyhydroxyalkanoates (PHA) production using food waste (UFW) and effluents from acidogenic biohydrogen production process (FFW) were studied employing aerobic mixed culture as biocatalyst. Anoxic microenvironment documented higher PHA production, while aerobic microenvironment showed higher substrate degradation. FFW showed higher PHA accumulation (39.6%) than UFW (35.6%) due to ready availability of precursors (fatty acids). Higher fraction of poly-3-hydroxy butyrate (PHB) was observed compared to poly-3-hydroxy valerate (PHV) in the accumulated PHA in the form of co-polymer [P3(HB-co-HV)]. Dehydrogenase, phosphatase and protease enzymatic activities were monitored during process operation. Integration with fermentative biohydrogen production yielded additional substrate degradation under both aerobic (78%) and anoxic (72%) microenvironments apart from PHA production. Microbial community analysis documented the presence of aerobic and facultative organisms capable of producing PHA. Integration strategy showed feasibility of producing hydrogen along with PHA by consuming fatty acids generated during acidogenic process in association with increased treatment efficiency.

The feasibility of treating low-strength wastewater with an up-flow anaerobic sludge blanket (UASB) reactor, using a poly(vinyl alcohol)-gel carrier, at various temperatures and hydraulic retention times (HRTs) was examined. The temperature was decreased from 35°C to 25°C and then to 15°C. The HRT was reduced from 2.0 h to 0.22 h. The COD removal rate reached 28 kg-COD m(-3)d(-1) at 35°C, 16 kg-COD m(-3)d(-1) at 25°C, and 6 kg-COD m(-3)d(-1) at 15°C. The COD removal rate was reduced by half for each temperature reduction of 10°C.