Colour removal from textile waste water using bioculture in continous mode.

One of the environmental problems being faced by textile industry is the removal of colour from the dye wastewater prior to discharge to local sewage treatment facilities or adjoining water courses. During the past two decades, several physico-chemical methods like adsorption, chemical treatment and ion pair extractions were adopted and have been proved to be costly and less effective. Biological treatment methods are comparatively cheap and considered to be the best alternative with proper analysis and environmental control. With this in mind, an attempt was made to evaluate efficiency with mixed microbial cultures for the decolourisation of the dye wastewater in continuous mode operation. Laboratory scale models of anaerobic reactor, activated sludge process and sand filter were fabricated and operated in series. The activated bioclean was inoculated in the anaerobic reactor. The characteristics and treatability of the textile dye wastewater were analysed. The sample taken for the study was combined effluent collected from the equalization tank in Common Effluent Treatment Plant (CETP), Tirupur. The experiments were conducted for different organic loading rates. Parameters such as colour, pH, COD, BOD, suspended solids, total dissolved solids, chlorides and sulphates for both the influent and effluent were evaluated. The removal efficiency of the anaerobic process, activated sludge process and sand filter for the above said parameters were studied.

Study of hydrodynamic behavior of a laboratory scale upflow anaerobic fixed film fixed bed reactor.

Application of anaerobic fixed film fixed bed reactor (AFFFB), containing mixed population of bacteria, helps in bacterial immobilization as biofilm on a support medium in the reactor overcoming the problem of biomass washout. Knowledge of hydrodynamics characteristics helps in better understanding and evaluating the performance of any reactor. This paper presents residence time distribution (RTD) studies carried out to investigate the hydrodynamic behavior of AFFFB reactor under the influence of varied hydraulic loading resulting in HRTs in range 24 hrs to 6 hrs. Results have demonstrated that the flow pattern is more close to a plug flow type and vary with varying intensity of dispersion and the extent of dispersion increases with decrease in HRTs.

Modelling of secondary clarifier using regression analysis and artificial neural networks.

Mathematical models for the surface area of secondary clarifier were developed for wastewater generated from a dairy industry and from domestic sources, by correlating the parameters namely, surface area per unit flow rate (A/Q), influent concentration (C(O)), underflow concentration (C(U)), recycling ratio (r) and Mean Cell Residence Time (theta C) using multiple regression analysis. There was found a good correlation between the measured data and the model results with regression coefficients of 0.9. Thickener area requirement of combined wastewater was comparehat obtained for dairy wastewater. Thickener area was found to decrease with increase in Mean Cell Residence Time and the area required for treating the combined wastewater was less, when compared with the requirement for dairy wastewater treatment. Neural network was trained with experimental data to 'acquire' knowledge about it. The Back Propagation Network technique was used in which the error was back propagated through the network. The results evolved from the neural network training were compared with the results of regression model and experimental data. Greater deviation was observed between the observed and predicted values of A/Q at high underflow concentrations, indicating that the limiting solids flux was reached. The output from Neural Network approach had greater consistency with the experimental data than the output from conventional regression analysis. Hence, Artificial Neural Network technique is highly adaptive and efficient in investigating input - output relationships.

Treatment of spent wash in anaerobic mesophilic suspended growth reactor (AMSGR).

Approximately 400 KL of spent wash or vinasse per annum is generated at an average COD concentration of 100,000 mg/l, by over 250 distilleries in India. There is an urgent need to develop, assess and use ecofriendly methods for the disposal of this high strength wastewater. Therefore, an attempt was made to investigate a few aspects of anaerobic digestion of spent wash collected from a distillery. The study was carried out in a 4 L laboratory scale anaerobic mesophilic suspended growth reactor. After the successful startup, the organic loading was increased stepwise to assess the performance of the reactor. During the study period, biogas generated was recorded and the maximum gas generated was found to be 16.9 L at an Organic Loading Rate (OLR) of 38 g COD/L. A 500% increase in the Volatile Fatty Acid (VFA) concentration (2150 mg/L) was observed, when the OLR was increased from 38 to 39 g COD/L. During the souring phase the removal of COD, Total Solids (TS) and Volatile Solids (VS) were in the order of 52%, 40% and 46% respectively. The methane content in the biogas varied from 65% to 75%.