Swachchha Majumdar

Comparative study on treatment of kitchen-sink wastewater using single and multichannel ceramic membrane

A comparative study was conducted to explore the potential of ceramic microfiltration membrane alone and in combination with different physicochemical treatments, viz. biotreatment and adsorption using kitchen-sink wastewater. Cross-flow microfiltration (CMF) studies were carried out with tubular ceramic membrane in single channel and multichannel configuration. Biotreatment was studied using activated sludge process and adsorptive treatments were studied using a biosorbent prepared from the dried roots of Eichhornia crassipes, an aquatic weed which is abundantly grown in polluted water. The study showed better performance of 19 channel ceramic membrane compared to the single channel membrane in terms of the permeate quality, viz. BOD, COD, turbidity, TSS etc., as well as, permeate flux. Microfiltration of the adsorbent treated feed appeared to be most promising in comparison with the other feeds wherein, about 98% removal of BOD and 99% removal of COD were obtained. The quality of the treated water was found to be fit for use in horticulture, irrigation, etc.

Development of hydrophobic clay–alumina based capillary membrane for desalination of brine by membrane distillation

Abstract Clay–alumina compositions of 0, 20, 40 and 55 weight percent (wt%) clay and rest alumina were maintained in porous support preparation by extrusion followed by sintering at 1300 °C for 2.5 h to obtain 3 mm/2 mm (outer diameter/inner diameter) capillary. 1H,1H,2H,2H-perfluorodecyltriethoxysilane (97%) (C8) was used to modify the capillary surface of all compositions without any intermediate membrane layer to impart hydrophobic characteristics and compared in terms of contact angle produced by the capillaries with water and liquid entry pressure (LEPw). FTIR analysis showed that the hydrophilic surface of the capillary membranes was efficiently modified by the proposed grafting method. Capillary with 55 wt% clay produced a pore size of 1.43 micron and was considered as an ideal candidate for grafting with C8 polymer to impart surface hydrophobicity. The contact angle and LEPw value obtained for this modified membrane (C-55-M) were 145° and 1 bar, respectively. The modified capillary membrane was applied for desalination of brine by air gap membrane distillation (AGMD) at a feed pressure of 0.85 bar. Maximum flux obtained for C-55-M membrane was 98.66 L/m2 day at a temperature difference of 60 °C with salt rejection of 99.96%. Mass transfer coefficient of C-55-M was 16 × 10−3 mm/s at feed temperature of 70 °C.

Biosorbent-assisted ceramic microfiltration process for treatment of herbal pharmaceutical wastewater with high organic loading

The feasibility of treating herbal pharmaceutical wastewater with high Biochemical Oxygen Demand (BOD) and Chemical Oxygen Demand (COD) values was studied using ceramic microfiltration membrane in combination with an adsorptive treatment. Batch kinetic and isotherm studies were carried out under varying dosages of a biosorbent prepared from the roots of Eichhornia crassipes (ECR). Adsorption kinetic models, based on the assumption of the pseudo-first-order and pseudo-second-order models, were applied to examine the kinetics of the adsorption. Microfiltration study was carried out using uncoated porous ceramic membrane prepared from a mixture of α-alumina and clay in tubular multi-channel configuration. The efficiency of the separation process was evaluated in terms of turbidity, TSS, colour and COD and permeate flux rates were compared for different adsorbent loadings in the effluent. An effective removal of turbidity (>99%) and TSS (98?99%) was observed after 2 hours of microfiltration with colour removal of 87% and COD reduction of 88%.