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Background: The capsid coated protein of Bluetongue virus (BTV) VP2 is responsible for BTV transmission by the Culicoides vector to vertebrate hosts. Besides, VP2 is responsible for BTV entry into permissive cells and hence plays a major role in disease progression. However, its mechanism of action is still unknown. Objective: The present investigation aimed to predict the 3D structure of Viral Protein 2 of the bluetongue virus assisted by Optimized Potential for Liquid Simulations (OPLS), structure validation, and an active site prediction. Methods: The 3D structure of the VP2 protein was built using a Python-based Computational algorithm. The templates were identified using Smith waterman’s Local alignment. The VP2 protein structure validated using PROCHECK. Molecular Dynamics Simulation (MDS) studies were performed using an academic software Desmond, Schrodinger dynamics, for determining the stability of a model protein. The Ligand-Binding site was predicted by structure comparison using homology search and proteinprotein network analysis to reveal their stability and inhibition mechanism, followed by the active site identification. Results: The secondary structure of the VP2 reveals that the protein contains 220 alpha helix atoms, 40 310 helix, 151 beta sheets, 134 coils and 424 turns, whereas the 3D structure of Viral Protein 2 of BTV has been found to have 15774 total atoms in the structure. However, 961 amino acids were found in the final model. The dynamical cross-correlation matrix (DCCM) analysis tool identifies putative protein domains and also confirms the stability of the predicted model and their dynamical behavior difference with the correlative fluctuations in motion. Conclusion: The biological interpretation of the Viral Protein 2 was carried out. DCCM maps were calculated, using a different coordinate reference frame, through which, protein domain boundaries and protein domain residue constituents were identified. The obtained model shows good reliability. Moreover, we anticipated that this research should play a promising role in the identification of novel candidates with the target protein to inhibit their functional significance.

N-acyl homoserine lactones (AHLs) based quorum sensing controls various phenotype expressions, including biofilm formation, hence its interruption is considered to be an ideal option for membrane biofouling control. Bead entrapped quorum quenching bacteria was reported to be an efficient approach for degradation of signal molecules in recent years. In the present study, we investigated the potential of quorum quenching (QQ) bacteria immobilised magnetic nanocomposite beads (IMN) in degradation of signalling molecule, n-hexanoyl homoserine lactone (C6-HSL). Three QQ bacteria, named

A fed batch membraneless microbial electrolysis cell (MEC) was investigated for treating combined leachate and dairy wastewater at an applied voltage 0.8 V and hydraulic retention time (HRT) of 48 h. The COD (chemical oxygen demand) removal and energy recovery was tested by running several cycles of MEC with increasing ratios of leachate to dairy wastewater. With an increase in percentage of simulated leachate, MEC performance in terms of current generation, COD removal efficiency and hydrogen production showed a gradual decrease. A sudden drop in reactor performance was noticed when the concentration of leachate was increased from 14 to 16% corresponding to an increase in Organic Load Rate (OLR) from 23.89gCOD/m3/d to 24gCOD/m3/d. A continued operation of MEC at an OLR of 24gCOD/m3/d for ten continuous cycles resulted in COD removal efficiency of 73% and hydrogen production of 15 mL/L/d with current density of 10 A/m2 and a power density of 80 mW/cm2.

In the present investigation, azophloxine dye decolourization with lignolytic enzyme producing white rot fungi, Trametes versicolour (TV) and Phanerochaete chrysosporium (PC) co-cultures, was investigated. Co-culturing of TV and PC extended the laccase activity by 8.2 times as compared to monocultivation of TV. Phanerochaete chrysosporium, a non-laccase producing fungus, produced the enzyme due to hyphal modifications and synergistic interaction with Trametes versicolour. The crude laccase extracted from TV + PC co-cultures showed 87.6% decolourization when subjected to azophloxine dye for 48 h. Contrary, laccase extracted from TV self-pairing plates showed decolourization of 14.4%. Henceforth, this investigation demonstrated that co-culturing of two white rot strains improved dye decolourization by increasing laccase enzymatic action.

In photosynthetic microbial fuel cell (MFC), algae and photosynthetic bacteria undergo photosynthesis to generate electricity by harnessing the solar energy. The microorganisms on absorbing solar energy initiate a series of reactions to generate protons (H+ ions), electron, and oxygen through splitting of water. The energy from these reaction series is harnessed by placing photosynthetic organisms in anodic chamber separated from cathodic chamber by a semipermeable membrane selective for hydrogen ions. The electrons generated in an anodic chamber by photosynthetic activity of microbes travel through an outer circuit to the cathodic chamber, where they combine with protons and oxygen at the reductive electrode (cathode) to generate water. This technology has huge potential for converting solar energy into electrical energy and might also help to reduce the carbon footprint. The chapter discusses the concept, fundamentals, process design and operation of photosynthetic MFC. Furthermore, the role of photosynthetic organisms in MFC, various bottlenecks faced by MFC systems and their potential applications are also outlined in the chapter.

Biological photovoltaic cells can be called as living solar cells. They use oxygenic photoautotrophs such as cyanobacteria and algae, instead of silicon, to capture light energy for photolysis. The organisms such as cyanobacteria and algae capture light energy during the process of photosynthesis and perform charge separation of water molecules (photolysis), producing protons, electrons, and oxygen molecules. The electrons thus produced are transferred to the anode and through external circuit they move to cathode to get reduced to water, producing electric current. Biophotovoltaic (BPV) are different from traditional silicon based solar photovoltaics (SPV) cells in a number of ways. Unlike SPV, the presence of water is imperative in BPV for the algae/cyanobacteria to perform photolysis. The BPV are self-renewing in nature and do not require any external carbon source for growth. The technology of BPV can be incorporated in bioelectrochemical systems (BES) to generate green energy. BPV based electrochemical technology can be used as solar bio-battery or bio-solar panel. It can also be utilized in low powered devices such as alarm clocks. Despite the multiple advantages of BPV, still they are in the threshold of its development due to its energy conversion efficiency. The chapter would comprehensively explain the principle, working, and application of biological photovoltaic systems.

Food waste is one of the most prevalent global challenges. Population growth, the rapid increase in urbanization coupled with industrial development, and changes in lifestyles and economic status have resulted in the generation of tremendous amounts of food waste. According to FAO reports, around 1.3 billion tonnes of food is wasted annually, which is equivalent to more than half of the world’s total cereal production. When disposed off, this waste creates many economic, societal, and environmental concerns. Food waste when disposed of in landfills produces harmful greenhouse gases such as methane and carbon dioxide, contributing to global warming and climate change. Natural resources such as land, freshwater, fossil fuels, and human resources are also wasted. Hence, to manage this food waste, innovative and sustainable valorization technologies are required as part of waste recycling and recovery in food waste management. Food waste valorization results in the production of fuels, materials, and chemicals through various chemical and biochemical processes. Amidst the numerous researches on the conversion of food waste into high-value commodities and specialty products, in-depth analysis of different valorization technologies on society, the environment, and the economy remain to be scrutinized properly. In this chapter, different valorization technologies have been evaluated from social, environmental, and health perspectives. Also, necessary steps to be taken to prevent impacts arising during valorization, as well as new innovative plans to embark upon any detrimental impacts, are also been discussed in detail.

Biofouling control via quorum quenching (QQ) approach is becoming popular among other fouling mitigation strategies. In the present study, the mitigation of membrane biofouling problem via disruption of cell-to-cell communication was studied by immobilizing QQ bacteria in sodium alginate magnetic nanocomposite beads. Two QQ bacteria viz. Pseudomonas nitroreducens JYQ3 and Pseudomonas JYQ4 isolated from dairy waste activated sludge was immobilized individually into the beads. Scanning electron microscopy (SEM) analysis revealed the successful immobilization of QQ bacteria into the alginate nanoparticle beads. The Confocal laser scanning microscopy (CLSM) results provided evidence of biofouling controlled activities of Pseudomonas nitroreducens JYQ3 and Pseudomonas JYQ4 immobilized nanocomposite (IMN) beads. Further, the membranes incubated with Pseudomonas nitroreducens JYQ3 and Pseudomonas JYQ4 IMN beads showed better flux (19% and 22% higher, respectively) than the control. Hence, the results revealed that the QQ bacteria IMN beads would be an efficient approach for controlling the biofilm developed on the cellulose acetate membrane surface.

Intercellular bacterial communication process via exchange of signalling molecules acyl homoserine lactone results in various group activities like bioluminescence, antibiotic production, biofilm formation, sporulation, and virulence. The signalling molecules are targeted, and the communication is interrupted by a group of bacteria termed quorum quenching bacteria. The present study aims to isolate the quorum quenching bacteria from the waste activated sludge collected from the dairy industry effluent treatment plant and explore for its quorum quenching potential. The bacteria were cultured in the KG medium containing n-hexanoyl homoserine lactone as a sole source of carbon and nitrogen. The isolates were identified by the 16S ribosomal deoxyribonucleic acid analysis and subsequently were evaluated for its quorum quenching activity through Chromobacterium violaceum CV026 biosensor assay. The n-hexanoyl homoserine lactone degradation was quantified by GC–MS analysis. The 16S ribosomal deoxyribonucleic acid analysis revealed the isolated bacteria as Klebsiella pneumoniae (JYQ1 and JYQ5), Acinetobacter baumannii JYQ2, Pseudomonas nitroreducens JYQ3, and Pseudomonas JYQ4. The biosensor strain assay and GC–MS analysis indicated that all the isolates possessed an inherent ability to degrade N-hexanoyl homoserine lactone. The strain Pseudomonas JYQ4 exhibited the highest quorum quenching activity of 84 ± 3.3% within 6 h of incubation. The strain A. baumannii JYQ2 acted both as quorum sensing and as quorum quenching bacteria as evidenced by the decrease in quorum quenching from 79 ± 3.1 to 76.8 ± 2.5%.

The present study assesses the performance of microbial electrolysis cell (MEC) to generate electric current using (I) uncoated/untreated electrodes and (II) Fe3O4 nanoparticles (FNPs) coated electrodes. The cyclic voltammetry (CV) reports highest conductivity of 58 Sm−1 in (II) while lowest (0.18 Sm−1) in (I) electrodes. The impedance spectroscopy confirms bulk resistivity of 375 kΩ in (I) electrodes while relatively lowest resistivity of 0.4 kΩ in (II) electrodes. Two sets of single chamber membraneless MECs is operated simultaneously at different applied voltage (300 mV, 500 mV and 700 mV): RI (uncoated electrodes) and RII, (FNP coated electrodes). The RII attains maximum current density and power density of 15.2 mAcm−1 and 10.6 mWcm−2 respectively at 0.7 V while RI achieves the maximum current density and power density of 4.03 mAcm−2 and 2.8 mWcm−2 respectively at same voltage. Moreover, the current density recorded in electrodes (II) is significantly higher compared to electrodes (I) measured using CV. The result suggests FNP to be an excellent catalyst which improves biosynthesis of electric current. The biologically active environment consisting of anaerobic electrogenic microbes supported biosynthesis/generation of high electric current along with other metabolites produced from the microbes mediated redox reaction.

In this study, the performance of continuous fed upflow anaerobic microbial fuel cell operated with surgical cotton industry wastewater was investigated at different Organic Loading Rate (OLR). The potency of power generation, COD and TSS removal efficiency was determined. The highest TCOD and SCOD removal of 78.8% and 69%, respectively was accomplished at an optimum OLR of 1.9 gCOD/L d. A 62% TSS removal efficiency was obtained, with an initial TSS concentration of wastewater as 970 ± 70 mg/L. The maximum power density 116.03 mW/m2 (2.2 W/m3) and corresponding coulombic efficiency of 17.8% was achieved at the OLR of 1.9 gCOD/L/d while treating surgical cotton industry waste water.

Chlorpyrifos degradation was studied using laccase immobilized on magnetic iron nanoparticles (CENPs). The magnetic iron nanoparticles (MNPs) prepared by co-precipitation method were characterized using Transmission electron microscopy (TEM), Scanning electron microscopy- Energy dispersive spectroscopy (SEM-EDS) and Thermogravimetric analysis (TGA). The size of the nanoparticles ranged between 10 and 15 nm. The MNPs were coated with chitosan, surface modified with carbodiimide (EDAC) immobilized with laccase enzymes. The chlorpyrifos degradation studies were performed in batch studies under constant shaking for a period of 12 h. Results of the study showed that laccase immobilized on magnetic iron nanoparticles were effective in degrading more than 99% chlorpyrifos in 12 h at pH 7 and 60 °C. In the overall degradation percentage, MNPs contributed to 32.3% of chlorpyrifos removal while ENPs resulted in 58.8% chlorpyrifos degradation. Immobilization of enzyme decreased the overall activity of the free enzyme. The CENPs showed 95% activity after five repeated washing and hence possess good reusability potential.

Climate change is perhaps one of the major critical problems of recent times. It has become a subject of international concern since its increase at an alarming speed. Although atmospheric gases, surface solar radiations, volcanic activity, cosmic rays and alterations in earth’s orbit are targeted as the potential causes of climate change, their consequences or impacts are not well documented. Sea level rise, flooding, extreme weather patterns, heat waves and drought are some of the pronounced consequences of climate change. Changes in biodiversity, ecosystem and ecosystem services and health caused by climate change have received minimal attention. A healthy ecosystem requires a wide diversity of microorganisms, plants and animals at different trophic levels. Removal of a single species from the niche or introduction of an invasive species might lead to ecosystem destruction. Abnormal changes in the climate pattern can alter the ecosystem health through loss of species, extinction of species, migration of species and changes in behavioural pattern. However, these changes are invisible till a species get extinct or endangered. Further the change in ecosystem health due to alterations in climate is difficult to record unlike other impacts. Sustainable practices that can reduce, sequester or capture the greenhouse gas emissions may halt the biodiversity loss, protect the ecosystem from further destruction and restore them. This chapter comprehensively describes the impacts of climate change on the health of various aquatic and terrestrial ecosystems. The detrimental effects, short- and long-term responses like changes in physiology, phenology and life cycle of organisms, loss of productivity and loss or migration of species have also been elaborated in detail for every single ecosystem.

The food industry generates enormous quantity of food waste (FW) either directly or indirectly including the processing sector, which turned into biofuels for waste remediation. Six types of food processing wastes (FPW) such as oil, fruit and vegetable, dairy, brewery, livestock and finally agriculture based materials that get treated via dark fermentation/anaerobic digestion has been discussed. Production of both hydrogen and methane is daunting for oil, fruit and vegetable processing wastes because of the presence of polyphenols and essential oils. Moreover, acidic pH and high protein are the reasons for increased concentration of ammonia and accumulation of volatile fatty acids in FPW, especially in dairy, brewery, and livestock waste streams. Moreover, the review brought to forefront the enhancing methods, (pretreatment and co-digestion) operational, and environmental parameters that can influence the production of biohythane. Finally, the nature of feedstock's role in achieving successful circular bio economy is also highlighted.

Plastics have become an indispensable part of the society. Lightweight, easy handling, durability, flexibility, resistance to water, and other microbial attacks have made them ubiquitously popular. The extensive use of the long-lived polymer has confronted the environment with a challenging plastic pollution problem. Plastics are the product of coal, natural gas, crude oil, cellulose, and salt manufactured through energy-intensive technology. From cradle to grave, plastics affect the environment in a multifaceted way. The hazardous and ecologically (terrestrial and marine) damaging threats necessitate its removal from the environment. Incineration, landfilling, recycling, and degradation are the four most available options to manage the plastic waste. However, to avoid long-term environmental damage, degradation of plastic is the most preferred option among the management options. Plastic degradation is carried out by photodegradation, thermooxidative degradation, hydrolytic degradation, and biodegradation. Among them, microbial degradation using bacteria and fungi is an emerging strategy to manage plastic waste. Hence, this chapter highlights the benefits, concerns, and threats surrounding the use of plastics. The different perspectives covered in this chapter include plastic production and plastic waste generation, environmental and health effects of plastic pollution, plastic waste management options, biodegradation of plastic polymers and the mechanism involved, biodegradable plastics, and challenges and constraints of plastic waste biodegradation.

Heterogeneity, recalcitrance, and ubiquitous persistence of textile effluent make it the foulest industrial pollutant which poses a serious threat to soil and water bodies. Textile effluent like all other industrial effluents contributes considerably to environmental pollution. Presence of huge amount of water-soluble unfixed dyes, heavy metals, acids, alkalis, inorganic and organic salts has resulted in a highly concentrated, colored, and complex high strength wastewater that resists degradation. The conventional treatment methods including biological and physicochemical methods for treatment of textile waste are not convincing enough because of low biodegradability of dyes, fouling of filters, high pressure requirement, and generation of sludge containing iron hydroxide. Hence, it has become imperative to seek alternative advanced technology which must be essentially environment competent. Exquisite properties are shown to be possessed by the nanoparticles making it an efficient technology for cleanup of environmental pollutants. Nanoremediation is an upcoming field of research with huge prospects in the treatment of environmental contaminants. In addition to its high reactivity with the contaminants, they also act as suitable carriers for immobilization of whole cells and enzymes. Effluent treatment aided by enzymes has been demonstrated to be effective for recalcitrant pollutants and requires moderate reaction conditions, making them environmentally sound. The generic enzymes sought for the treatment of textile pollutants include most of the peroxidase, cytochrome reductase (Fe III), and oxidoreductase. This chapter extensively covers current know-how of nanoparticles as a carrier for several enzymes for the degradation of pollutants present in textile wastewater. The role of nanoparticle in the removal of dyes is also highlighted.

Covalent-immobilization of the laccase enzyme onto the iron oxide nanoparticles was achieved using N-(3-Dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride (EDAC) as cross-linkers. The presence of sulphur moeity in the laccase immobilized nanoparticles (LNPs) observed through Scanning Electron Microscopy- Energy dispersive X-ray spectroscopy (SEM-EDS) spectra confirmed the immobilization of laccase enzyme. The TEM analysis of iron oxide nanoparticles (FNPs), chitosan coated iron nanoparticles (CNPs) and laccase immobilized nanoparticles (LNPs) confirmed their sizes around 12, 15 and 20 nm, respectively. The effect of LNPs in degrading chlorpyrifos under field conditions was studied by simulating the conditions in a column. Column A, which was used as control showed more leaching of chlorpyrifos as compared to column B containing LNPs. The sorption coefficient (Kd) value obtained for control (column A) and LNPs containing column B were 21.6 and 112.3 L/kg, respectively. LNPs altered the Kd values of soil thereby showing lesser leaching potential. Higher the Kd value, lesser will be the leaching potential in the ground water. Copper in laccase enzyme resulted in hydrolysis of chlorpyrifos. Chitosan used for coating on FNPs and soil organic matter resulted in the adsoption of chlorpyrifos. Current results will allow a better assessment of the role of LNPs as a competent deterrent in chlorpyrifos mobility and degradation.

The effect of combined surfactant-dispersion pretreatment on dairy waste activated sludge (WAS) reduction in anaerobic digesters was investigated. The experiments were performed with surfactant, Sodium dodecyl sulfate (SDS) in the range of 0.01 to 0.1 g/g suspended solids (SS) and disperser with rpm of 5000-25,000. The COD (chemical oxygen demand) solubilization, suspended solids reduction, and biogas generation increased for an energy input of 7377 kJ/kg total solids (TS) (12,000 rpm, 0.04 g/g SS, and 30 min) and were found to be 38, 32, and 75 %, higher than that of control. The pretreated sludge improved the performance of semicontinuous anaerobic digesters of 4 L working volume operated at four different SRTs (sludge retention time). SRT of 15 days was found to be appropriate showing 49 and 51 % reduction in SS and volatile solids (VS), respectively. The methane yield of the pretreated sample was observed to be 50 mL/g VS removed which was observed to be comparatively higher than the control (12 mL/g VS removed) at optimal SRT of 15 days. To the best of the authors' knowledge, this study is the first to be reported and not yet been documented in literature.

In this study, the effect of Ethylene diamine tetra acetic acid (EDTA) on Extracellular polymeric substance (EPS) removal tailed with bacterial enzymatic pretreatment on aerobic digestion of activated sludge was studied. In order to enhance the accessibility of sludge to the enzyme secreting bacteria; the extracellular polymeric substances were removed using EDTA. EDTA efficiently removed the EPS with limited cell lysis and enhanced the sludge enzyme activity at its lower concentration of 0.2 g/g SS. The sludge was then subjected to bacterial pretreatment to enhance the aerobic digestion. In aerobic digestion the best results in terms of Suspended solids (SS) reduction (48.5%) and COD (Chemical oxygen demand) solubilization (47.3%) was obtained in experimental reactor than in control. These results imply that aerobic digestion can be enhanced efficiently through bacterial pretreatment of EPS removed sludge.

The present study was conducted to investigate copper tolerance and bioremediation potential in endophytic bacteria isolated from Vigna unguiculata root nodules. Total ten endophytes were isolated on yeast mannitol agar and enriched in copper (II) sulfate (CuSO4) up to 500 mg/L. Four endophytes belonging to genera Bacillus and Arthrobacter showed copper tolerance. The isolates were identified as Arthrobacter tumbae MYR1, Bacillus safensis MYR2, Bacillus pumilus MYR3 and Bacillus sp. MYR4 using 16S ribosomal RNA (rRNA) analysis. Response surface methodology was used for copper (II) removal optimization. The model was significant with R 2, P and F value of 0.9780

Tubular upflow microbial fuel cell (MFC) utilizing sea food processing wastewater was evaluated for wastewater treatment efficiency and power generation. At an organic loading rate (OLR) of 0.6 g d(-1), the MFC accomplished total and soluble chemical oxygen demand (COD) removal of 83 and 95%, respectively. A maximum power density of 105 mW m(-2) (2.21 W m(-3)) was achieved at an OLR of 2.57 g d(-1). The predominant bacterial communities of anode biofilm were identified as RB1A (LC035455), RB1B (LC035456), RB1C (LC035457) and RB1E (LC035458). All the four strains belonged to genera Stenotrophomonas. The results of the study reaffirms that the seafood processing wastewater can be treated in an upflow MFC for simultaneous power generation and wastewater treatment.

Bluetongue is a highly infectious vector born viral disease, and it is a disease of wild and domestic animals (ruminants). Bluetongue is a non-contagious disease of animals and spread by the biting midges (Sperlova. A. and Zendulkova. D. 2011). The name Bluetongue is given by Spreull in 1905 (Spreull, 1905). Bluetongue disease is mild in goats and severe in sheep as sheep is the primary host of bluetongue virus. Cattle act as the reservoir of bluetongue virus (Browne, 1971). The Bluetongue virus is first reported by hutcheon in 1881 During the introduction of European sheep breeds in Southern Africa (Hutcheon, 1902). Later in 1948 it was reported in North America as a sore muzzle disease (Hardy and Price, 1952).). Spare in 1964 reported outbreak of bluetongue disease in India (Spare, 1964). There are several clinical symptoms of Bluetongue disease have been found in ruminants like fever, viraemia, sore muzzle, facial oedema, hyperaemia and congestion, erosion of mucous membrane, haemorrhages, vascular permeability (OIE, 2014). Symptoms are more severe and easily detectable in sheep and these signs are high fever upto 5–7 days, loss of wool, depression and haemorrhages in the coronary band, difficulty in standing and lameness because of painful hoof, excessive salivation, swollen tongue, swelling in nasal and buccal mucosa, pneumonia and death (Tabachnick et.al., 2009). The Severity of clinical signs of bluetongue disease in sheep influenced by the type and strain of infecting virus (Verwoerd & Erasmus, 2004; OIE, 2014). The bluetongue virus is hypervariable in nature therefore, there are 24 serotypes of bluetongue virus are well recognised with two newly proposed serotypes BTV 25 from Switzerland and BTV 26 from Kuwait. In India 22 serotypes have been reported of Bluetongue virus (Prasad et al., 2009; Kumar, 2009). Bluetongue virus belongs to family Reoviridae and genus Orbivirus (Tabachnick et al., 2009). Blue-tongue has a serious economic impact on dairy and wool industry mainly due to high morbidity, mortality and mandatory trade barrier on the movement of BT infected livestock and germ-plasm. BT is evolving into newer challenges and poses ever increasing the threat to associated environment. An Unnatural host like canines have in the past contracted BT infections. Many species of Culicoides have been reported to spread infections. Recently BT has been categorized as multispecies disease by OIE (2014).

Membrane bioreactor (MBR) is a promising technological option to meet water reuse demands. Though MBR provides effluent quality of reusable standard, its versatility to shock loads remains unexplored. The present study investigates the robustness of MBR under sodium chloride shock load (5-60 g/L) conditions. A bench scale aerobic submerged MBR (6L working volume) with polyethylene hollow fiber membrane module (pore size 0.4 microm) was operated with synthetic wastewater at steady state OLR of 3.6g COD/L/d and HRT of 8h. This resulted in 99% TSS removal and 95% COD and TKN removal. The COD removal during the salt shock load was in the range of 84-64%. The TSS removal showed maximum disturbance (88%) with a corresponding decrease in biomass MLVSS by 8% at 60 g/L shock. TKN removal was reduced due to inhibition of nitrification with increasing shock loads. It took about 4-9 days for the MBR to regain its steady state performance.

A Membrane Bioreactor (MBR) treating simulated sewage was operated and stabilised for a period of 60 days at an organic loading rate of 3.6 g/COD/day and Hydraulic Retention Time (HRT) of 8 h, during which the MBR showed 95% removal of Chemical Oxygen Demand (COD), 98% removal of Total Organic Carbon (TOC) and TSS, 91% removal of Total Kjeldahl Nitrogen (TKN) and 30% removal of phosphate. The responses of the MBR to different hydraulic shock loadings were studied. The HRT was reduced to 4 h, 2 h, 1 h and 0.8 h to simulate two, four, eight and tenfold increase in flow rate, respectively, for a period of 12 h. During the shock load the influent COD concentration was maintained constant. Under the hydraulic shocks, the COD removal efficiency temporarily reduced to between 92% and 81% and the TOC removal efficiency reduced to between 80% and 48%. TOC removal efficiency was very poor at tenfold hydraulic shock. The TKN and phosphate removal efficiency were slightly affected at twofold hydraulic shock, showing a removal efficiency of 76% and 24%, respectively. The nitrogen and phosphate removal was highly affected at higher shock loads with very high TKN and phosphate concentration in the effluent. The system took much longer time (around 7 to 14 days) to recover in terms of nutrient removal for higher shock loads. The biomass was not at all affected at two, four and eightfold increase in flow rate. The high biomass and sludge retention of the MBR is advantageous to withstand such high and sudden hydraulic shocks, with its ability to recover faster than any other biological reactor.