Research Publications (Water and Wastewater Technology)
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Item Phenotypic and genotypic characterisation of an unique indigenous hypersaline unicellular cyanobacterium, Euhalothece sp.nov(Elsevier, 2018) Mogany, Trisha; Swalaha, Feroz Mahomed; Allam, Mushal; Mtshali, Phillip Senzo; Ismail, Arshad; Kumari, Sheena K.; Bux, FaizalA novel halotolerant species of cyanobacterium of the order Chroococcales was isolated from hypersaline estuary in Kwa-Zulu Natal, South Africa. A comprehensive polyphasic approach viz., cell morphology, pigment com-position and complete genome sequence analysis was conducted to elucidate the taxonomic position of the isolated strain. The blue-green oval to rod-shaped cells were 14–18 μm in size, and contained a high amount of phycocyanin pigments. The strain was moderate thermotolerant/alkalitolerant halophile with the optimum conditions for growth at 35 °C, pH 8.5 and 120 g/l of NaCl. Based on 16S rRNA gene sequence phylogeny, the strain was related to members of the ‘Euhalothece’ subcluster (99%). The whole genome sequence was de-termined, and the annotated genes showed a 90% sequence similarity to the gas-vacuolate, spindle-shaped Dactylococcopsis salina PCC 8305. The size of the genome was determined to be 5,113,178 bp and contained 4332 protein-coding genes and 69 RNA genes with a G + C content of 46.7%. Genes encoding osmoregulation, oxi-dative stress, heat shock, persister cells, and UV-absorbing secondary metabolites, among others, were identified. Based on the phylogenetic analysis of the 16S rRNA gene sequences, physiological data, pigment compositions and genomic data, the strain is considered to represent a novel species of Euhalothece.Item Sorption isotherms, kinetic and optimization process of amino acid proline based polymer nanocomposite for the removal of selected textile dyes from industrial wastewater(Elsevier, 2016-10-18) Raghunath, Sharista; Anand, Krishnan; Gengan, Robert Moonsamy; Nayunigari, Mithil Kumar; Maity, ArjunIn this article, adsorption and kinetic studies were carried out on three textile dyes, namely Reactive Blue 222 (RB 222), Reactive Red 195 (RR 195) and Reactive Yellow 145 (RY 145). The dyes studied in a mixture were adsorbed under various conditions onto PRO-BEN, a bentonite modified with a new cationic proline polymer (L-proline-epichlorohydrin polymer). The proline polymer was characterized by 1H NMR, Fourier transform infrared spec-troscopy (FT-IR), dynamic light scattering (DLS) and TEM. The PRO-BEN composite was characterized by FT-IR, dynamic light scattering (DLS) (zeta potential), TEM imaging, SEM/EDX and X-ray photoelectron spectroscopy (characterize the binding energy). During adsorption studies, factors involving pH, temperature, the initial con-centrations of the dyes and the quantity of PRO-BEN used during adsorption were established. The results re-vealed that the adsorption mechanism was categorized by the Langmuir type 1 isotherm. The adsorption data followed the pseudo-second order kinetic model. The intraparticle diffusion model indicated that adsorption did not only depend on the intraparticle diffusion of the dyes. The thermodynamic parameters verified that the adsorption process was spontaneous and exothermic. The Gibbs free energy values indicated that physisorption had occurred. Successful adsorption of dyes from an industrial effluent was achieved. Desorption studies concluded that PRO-BEN desorbed the dyes better than alumina. This can thereby be viewed as a recycla-ble remediation material. The PRO-BEN composite could be a cost efficient alternative towards the removal of or-ganic dyes in wastewater treatment.Item Characterization of brewery wastewater composition(WASET, 2015) Enitan, Abimbola Motunrayo; Adeyemo, Josiah; Kumari, Sheena K.; Swalaha, Feroz Mahomed; Bux, FaizalIndustries produce millions of cubic meters of effluent every year and the wastewater produced may be released into the surrounding water bodies, treated on-site or at municipal treatment plants. The determination of organic matter in the wastewater generated is very important to avoid any negative effect on the aquatic ecosystem. The scope of the present work is to assess the physicochemical composition of the wastewater produced from one of the brewery industry in South Africa. This is to estimate the environmental impact of its discharge into the receiving water bodies or the municipal treatment plant. The parameters monitored for the quantitative analysis of brewery wastewater include biological oxygen demand (BOD5), chemical oxygen demand (COD), total suspended solids, volatile suspended solids, ammonia, total oxidized nitrogen, nitrate, nitrite, phosphorus and alkalinity content. In average, the COD concentration of the brewery effluent was 5340.97 mg/l with average pH values of 4.0 to 6.7. The BOD5 and the solids content of the wastewater from the brewery industry were high. This means that the effluent is very rich in organic content and its discharge into the water bodies or the municipal treatment plant could cause environmental pollution or damage the treatment plant. In addition, there were variations in the wastewater composition throughout the monitoring period. This might be as a result of different activities that take place during the production process, as well as the effects of peak period of beer production on the water usage.Item Synthesis and performance evaluation of a new polymeric composite for the treatment of textile wastewater(ACS Publications, 2015) Gupta, Sanjay Kumar; Nayunigari, Mithil Kumar; Misra, Rohit; Ansari, Faiz Ahmad; Dionysiou, Dionysios (Dion) D.; Maity, Arjun; Bux, FaizalAzo dyes are synthetic colorants widely used in textile industry and are considered to be major contaminants in dye wastewater. Coagulation−flocculation is most preferred techniques to treat dye wastewater. A N,N-diisopropylamine-based new polymer was synthesized by polycondensation of epichlorohydrin, N,N-diisopropylamine, and ethylinediamine. The chemical and thermal properties of the polymer were investigated by FTIR, XRD, TGA, and viscosity measurements. The flocculation efficiency of the polymer was evaluated at different coagulant dose, organic load, and pH. The flocculation efficiency of this polymer was found to be higher over a pH range of 2−10 at its optimal dose of 80 mg/L. Morphological changes in the floc were studied by light and scanning electron microscopy. The zeta potential results clearly indicated that flocculation at the optimum doses is the result of charge neutralization and adsorption bridging. This study demonstrates the successful synthesis of the polymer, its excellent color removal efficiency (>98%) at lower doses, and effectiveness in dye wastewater treatment.Item Uptake of inorganic and organic nutrient species during cultivation of a Chlorella Isolate in Anaerobically digested dairy waste(American Institute of Chemical Engineers, 2016-06-23) Wahal, Shantanu; Viamajala, SridharA natural assemblage of microalgae from a facultative lagoon system treating municipal wastewater was enriched for growth in the effluents of an anaerobic digester processing dairy waste. A green microalga with close resemblance to Chlorella sp. was found to be dominant after multiple cycles of sub-culturing. Subsequently, the strain (designated as LLAI) was isolated and cultivated in 203 diluted digester effluents under various incident light intensities (255–1,100 mmoles m22 s21) to systematically assess growth and nutrient utilization. Our results showed that LLAI production increased with increasing incident light and a maximum productivity of 0.34 g L21 d21 was attained when the incident irradiance was 1,100 mmoles m22 s21. Lack of growth in the absence of light indicated that the cul-tures did not grow heterotrophically on the organic compounds present in the medium. How-ever, the cultures were able to uptake organic N and P under phototrophic conditions and our calculations suggest that the carbon associated with these organic nutrients contributed significantly to the production of biomass. Overall, under high light conditions, LLAI cul-tures utilized half of the soluble organic nitrogen and >90% of the ammonium, orthophos-phate, and dissolved organic phosphorus present in the diluted waste. Strain LLAI was also found to accumulate triacylglycerides (TAG) even before the onset of nutrient limitation and a lipid productivity of 37 mg-TAG L21 d21 was measured in cultures incubated at an inci-dent irradiance of 1,100 mmoles m22 s21. The results of this study suggest that microalgae isolates from natural environments are well-suited for nutrient remediation and biomass pro-duction from wastewater containing diverse inorganic and organic nutrient speciesItem Polyhydroxyalkanoates production from fermented paperboard mill wastewater using acetate-enriched bacteria(Springer-Verlag Berlin Heidelberg, 2017) Farghaly, Ahmed Mustafa; Enitan, Abimbola Motunrayo; Kumari, Sheena K.; Bux, Faizal; Tawfik, AhmedThe aim of the study was to investigate the use of dark fermented paperboard mill wastewater (PMW) containing volatile fatty acids for polyhydroxyalkanoates (PHA) production. Six sequencing batch reactors (SBRs) were initially fed with synthetic feed containing acetate and operated at different organic loading rates (OLRs) of 0.5, 1.0, 1.5, 2.0, 2.5, and 3.0 gCOD l-1 day-1 for PHA-storing bacteria enrichment. The maximum PHA content and yield (YPHA/S) were 67.44 ± 5.88 % and 0.45 ± 0.39 C-mol C-mol-1 at OLR of 1.5 gCOD l-1 day-1, respectively. The synthetic feed was replaced by dark fermented PMW effluent rich in acetate, butyrate, propionate, and lactate at the accumulation stage resulting in a PHA content and yield of 58.57 ± 4.02 % and 0.46 ± 0.09 C-mol C-mol-1, respectively. The maximum specific PHA production rate max ) amounted to 0.29 ± 0.1 C-mol C-mol-1 X-1 h-1.(qPHA Illumina MiSeq sequencing of bacterial 16S rRNA gene showed that Proteobacteria and Bacteroidetes increased from 37.4 to 77.6 % and from 2.49 to 17.66 % at enrich-ment and accumulation stages, respectively. Actinobacteria (15.44 %), Chloroflexi (8.15 %), Planctomycetes (7.46 %), and Acidobacteria (6.0 %) were detected at the enrichment SBRs.Item Dual role of Chlorella sorokiniana and Scenedesmus obliquus for comprehensive wastewater treatment and biomass production for bio-fuels(Elsevier, 2016) Gupta, Sanjay Kumar; Ansari, Faiz Ahmad; Shriwastav, Amritanshu; Sahoo, Narendra Kumar; Rawat, Ismail; Bux, FaizalMicroalgal treatment of raw sewage presents many complexities, mainly resulting from the inability of the algal species to sustain increased physiological stresses due to variable nutrient levels and high concentrations of organics. Chlorella sorokiniana and Scenedesmus obliquus have been identified to tolerate higher amounts of organic loading and physiological stresses. Nutrient removal, pathogen removal, and lipid accumulation with secondary or tertiary effluents have been demonstrated inde-pendently for these organisms. However, their potentials for accomplishing these objectives simulta-neously with raw sewage have not been investigated. This study presents comprehensive investigations of applicability of C. sorokiniana and S. obliquus to wastewater treatment without the requirement for any additional treatment. S. obliquus showed greater potential for removing organic carbon (76.13 ± 1.59%COD removal), nutrients (98.54 ± 3.30% N-removal, 97.99 ± 3.59% P-removal) and comparable pathogens removal (99.93 ± 0.12% total coliforms removal, 100% faecal coliform removal) in comparison to C. sorokiniana (69.38 ± 1.81% COD removal, 86.93 ± 3.49% N-removal, 68.24 ± 11.69% P-removal, 99.78 ± 0.12% total coliforms removal, 100% faecal coliform removal) with 15 days of cultivation with filtered raw sewage, but also encountered increased levels of stress (Fv/Fm of 0.48 ± 0.03) which accounted for increased lipid accumulation in the cells (23.26 ± 3.95% w/w) but might also affect their biomass productivity and treatment potential in longer applications. In comparison, C. sorokiniana demonstrated better adaptability to physiological stresses (Fv/Fm of 0.53 ± 0.01) and may be suitable for achieving comprehensive treatment and sufficient lipid accumulation (22.74 ± 3.11% w/w) without compromising these potentials during prolonged applications. These results highlight the importance of selecting algal species with better stress resistance to extend their applicability for comprehensive wastewater treatment and lipid production.Item An innovative electrochemical process to alleviate the challenges for harvesting of small size microalgae by using non-sacrificial carbon electrodes(Elsevier, 2015-09-04) Guldhe, Abhishek; Misra, Rohit; Singh, Poonam; Rawat, Ismail; Bux, FaizalHarvesting of microalgal biomass is still a bottleneck to its commercial scale application, due to small cell size, low culture densities, colloidal stability and thus unfavourable economics. Centrifugation is an efficient technique but the high energy consumption makes it unsuitable for low value microalgal products. Chemical flocculation and filtration are inefficient and time consuming methods for harvesting of small size microalgae. In this study, an electrochemical harvesting (ECH) process was assessed for the harvesting of a small size microalga Ankistrodesmus falcatus by using non-sacrificial carbon electrodes. Harvesting efficiency of ECH was compared to centrifugation and flocculation using alum and chitosan. The highest recovery efficiency was obtained by cen-trifugation (93% after 15 min) followed by ECH process (91% after 30 min), alum (86% after 60 min) and chitosan (55% after 60 min). However, the energy consumption of ECH process (1.76 kWh kg−1) was much lower than the centrifugation process (65.34 kWh kg−1). The biochemical composition of harvested biomass was also assessed, and it was found that the ECH process has no deteriorating effect on the quality of biomass. High recovery effi-ciency, low energy consumption and the use of non-sacrificial electrodes make ECH a sustainable harvesting technique for small size microalgae.Item Cultivation of Chlorella pyrenoidosa in outdoor open raceway pond using domestic wastewater as medium in arid desert region(Elsevier, 2016) Dahmani, Siham; Zerrouki, Djamal; Ramanna, Luveshan; Rawat, Ismail; Bux, FaizalChlorella pyrenoidosa was cultivated in secondary wastewater effluent to assess its nutrient removal capa-bilities. Wastewaters were obtained from a wastewater treatment plant located in Ouargla, Algeria. The experiments were conducted in winter under natural sunlight in an outdoor open raceway pond situated in the desert area. The highest biomass of the microalgae was found to be 1.71 ± 0.04 g/L. Temperatures ranged between 18 and 31 C. The average annual insolation was no less than 3500 h with an annual solar irradiance of more than 2000 kWh/m2. Analyses of different parameters including COD, NH4-N and TP were conducted throughout the cultivation period. Their average removal efficiencies were 78%, 95%and 81% respectively. The results demonstrated the potential of nutrient removal by microalgae grown on secondary wastewater in arid areas.Item A theoretical approach to using faecal indicator data to model norovirus concentration in surface water for QMRA : Glomma River, Norway(Elsevier, 2016) Petterson, Susan R.; Stenström, Thor-Axel; Ottoson, JakobMonitoring of faecal indicator organisms, such as Escherichia coli, in environmental and drinking waters is inadequate for the protection public health, primarily due to the poor relationship between E. coli and the occurrence of human pathogens, especially viruses, in environmental samples. Nevertheless, measurements of faecal indicator organisms within the risk based approach, can provide valuable information related to the magnitude and variability of faecal contamination, and hence provide insight into the expected level of potential pathogen contamination. In this study, a modelling approach is presented that estimates the concentration of norovirus in surface water relying on indicator monitoring data, combined with specific assumptions regarding the source of faecal contamination. The model is applied to a case study on drinking water treatment intake from the Glomma River in Norway. Norovirus concentrations were estimated in two sewage sources discharging into the river upstream of the drinking water offtake, and at the source water intake itself. The characteristics of the assumed source of faecal contamination, including the norovirus prevalence in the community, the size of the contributing population and the relative treatment efficacy for indicators and pathogens in the sewage treatment plant, influenced the magnitude and variability in the estimated norovirus concentration in surface waters. The modelling exercise presented is not intended to replace pathogen enumeration from environmental samples, but rather is proposed as a complement to better understand the sources and drivers of viruses in surface waters. The approach has the potential to inform sampling regimes by identifying when the best time would be to collect environmental samples; fill in the gaps between sparse datasets; and potentially extrapolate existing datasets in order to model rarer events such as an outbreak in the contributing population. In addition, and perhaps most universally, in the absence of pathogen data, this approach can be used as a first step to predict the source water pathogen concentration under different contamination scenarios for the purpose of quantifying microbial risks.