Sudesh Rathilal

STUDY OF THE START-UP OF AN UPFLOW LABORATORY-SCALE ANAEROBIC SLUDGE BLANKET FOR THE TREATMENT OF SLAUGHTERHOUSE WASTEWATER

The upflow anaerobic sludge blanket (UASB) process is a low-cost and low-skill requirement technology for reducing organic pollution loads especially for industries producing effluents in developing economies. A laboratory-scale UASB reactor was used for the treatment of slaughterhouse wastewater with the aim of studying its performance efficiency. The UASB reactor was seeded with digested sludge from a local water treatment plant treating domestic wastewater. Parameters such as pH, chemical oxygen demand (COD), biochemical oxygen demand (BOD), total suspended solids (TSS), volatile suspended solids (VSS) and volume of biogas generated during the digestion process were evaluated. The hydraulic retention time (HRT) was maintained at 12 hr while the organic loading rates were varied from 0.2–1.4 kg COD/(m3.d-1). The reactor was operated under mesophilic conditions. At the early stage of the start-up of the reactor, (COD) and (BOD) removal were in the range of 30–62%. The UASB reactor performed better at an organic loading rate (OLR) of 0.8 kg COD/(m .d 3 -1 with a COD removal of 86% as compared to the OLRs used in this experiment.

Evaluation of the effect of chemical cleaning on the performance of a nanofilter after textile wastewater treatment

E extraction (EME) is a sample preparation technique in pharmaceutical, chemical, clinical and environmental analysis. This technique uses electro-migration across artificial liquid membranes for selective extraction of analytes and sample enrichment from complex matrices. This method has many advantages such as simplicity, rapid, low-cost, low LOD, high pre-concentration factor and high recovery. In the present work, simultaneous pre-concentration and determination of two basic drugs namely metoclopramide (MCP) and ondansetron (OSN) were studied using EME as a suitable extraction method, followed with capillary electrophoresis (CE) using ultraviolet (UV) detection as separation technique. The drugs were extracted from 4 ml sample solutions, through a supported liquid membrane (SLM) consisting 2-nitrophenyloctylether (NPOE) impregnated in the walls of a polypropylene hollow fiber, and into a 20 mL acidic aqueous acceptor solution resent inside the lumen of the hollow fiber with a potential difference applied over the SLM. The variables of interest, such as chemical composition of the organic liquid membrane, stirring speed, extraction time and voltage, pH of donor and acceptor phases and salt effect in the EME process were investigated and optimized. Under optimal conditions NPOE as SLM, stirring rate of 1000 rpm, 200 V potential differences, 20 min as the extraction time, acceptor phase HCl (pH 1.0) and donor phase HCl (pH 1.5). After the microextraction process, the extracts were analyzed by CE with optimum conditions phosphate running buffer (pH 2.0), applied voltage of 20 kV and 25°C. Under the optimum conditions, limits of detection (LOD) and quantification (LOQ) for MCP and OSN were 2.31-2.68 and 7.72-8.91 ng mL-1 respectively. Pre-concentration factor and RSD for five replicates of each drug were calculated to be 200 and 4.06-3.93 respectively. Finally, the applicability of this method was studied by the extraction and determination of these drugs in urine samples with recovery percentages of 87–92%.The modern theory of phase transitions cannot explain the results of many experiments of interphase mass transfer. One reason for this is the assumption that during crystallization the solution is in the metastable state. The decomposition of the solution occurs by binodal scenario in this case. Crystallization nuclei form and grow in solution. The purpose of this study to show that in many cases the solution during crystallization is in an unstable state. The unstable condition leads to decomposition the solution by spinodal scenario