Comparative assessment of treatment of malathionlaced wastewater by single species (Pseudomonas Stutzeri) vs.activated sludge in a submerged membrane bioreactor

153-157Purification of water containing pesticide namely Malathion in membrane bioreator has been carried out. To understand the complex fouling mechanisms and fouling propensities occurring in a Membrane Bioreactor (MBR), in the current work, comparison of malathion degradation by single species, Pseudomonas Stutzeri, and microbial consortium has been carried out. Extracellular Polymeric Substances (EPSs) and Soluble Microbial Proteins (SMPs) are considered to increase the fouling. Experimental results revealed 85-90% reduction in the COD of the malathion containing synthetic wastewater and degradation kinetics has been reported. Complete reduction of malathion observed within 24 h in both the cases. A key parameter, critical flux is found to be 10 LMH for both the membrane bioreactor systems. Cake and Membrane resistances are calculated thus giving an insight regarding the working of Membrane Bioreactor based on single species and activated sludge

Arsenic and fluoride contaminated groundwaters: a review of current technologies for contaminants removal

Chronic contamination of groundwaters by both arsenic (As) and fluoride (F) is frequently observed around the world, which has severely affected millions of people. Fluoride and As are introduced into groundwaters by several sources such as water–rock interactions, anthropogenic activities, and groundwater recharge. Coexistence of these pollutants can have adverse effects due to synergistic and/or antagonistic mechanisms leading to uncertain and complicated health effects, including cancer. Many developing countries are beset with the problem of F and As laden waters, with no affordable technologies to provide clean water supply. The technologies available for the simultaneous removal are akin to chemical treatment, adsorption and membrane processes. However, the presence of competing ions such as phosphate, silicate, nitrate, chloride, carbonate, and sulfate affect the removal efficiency. Highly efficient, low-cost and sustainable technology which could be used by rural populations is of utmost importance for simultaneous removal of both pollutants. This can be realized by using readily available low cost materials coupled with proper disposal units. Synthesis of inexpensive and highly selective nanoadsorbents or nanofunctionalized membranes is required along with encapsulation units to isolate the toxicant loaded materials to avoid their re-entry in aquifers. A vast number of reviews have been published periodically on removal of As or F alone. However, there is a dearth of literature on the simultaneous removal of both. This review critically analyzes this important issue and considers strategies for their removal and safe disposal

Arsenic removal from natural waters by adsorption or ion exchange: an environmental sustainability assessment

The Environmental Sustainability Assessment of the adsorption and ion-exchange processes for arsenic removal was the focus of this work. The pursued goals were to determine the impact of regenerating the activated alumina used as adsorbent and the comparison of the environmental performance of two ion-exchange resins. Additional goals were the comparison between the environmental performance of adsorption and ion-exchange processes and the evaluation of the effect of integrating the proposed techniques on a water purification facility. The Life Cycle Inventory was obtained by means of simplified models and simulation. In this work it was concluded that the removal of As(V) by adsorption consumed between 2 and 13 times more primary resources and created 3–17 times more environmental burdens than the ion-exchange process. The integration of adsorption or ion-exchange technology in the drinking water plant would raise the primary consumption of energy, materials, and water by 27–155%, 7–94%, and 0.48–5.3%, respectively. The increase in the environmental burdens was mainly because of the generation of hazardous spent materials

Pharmaceutical industry wastewater: review of the technologies for water treatment and reuse

Pharmaceutical compounds are typically produced in batch processes leading to the presence of a wide variety of products in wastewaters which are generated in different operations, wherein copious quantities of water are used for washing of solid cake, or extraction, or washing of equipment. The presence of pharmaceutical compounds in drinking water comes from two different sources: production processes of the pharmaceutical industry and common use of pharmaceutical compounds resulting in their presence in urban and farm wastewaters. The wastewaters generated in different processes in the manufacture of pharmaceuticals and drugs contain a wide variety of compounds. Further, reuse of water after removal of contaminants, whether pharmaceuticals or otherwise, is required by industry. In view of the scarcity of water resources, it is necessary to understand and develop methodologies for treatment of pharmaceutical wastewater as part of water management. In this review, the various sources of wastewaters in the pharmaceutical industry are identified and the best available technologies to remove them are critically evaluated. Effluent arising from different sectors of active pharmaceutical ingredients (API), bulk drugs, and related pharmaceutics, which use large quantities of water, is evaluated and strategies are proposed to recover to a large extent the valuable compounds, and finally the treatment of very dilute but detrimental wastewaters is discussed. No single technology can completely remove pharmaceuticals from wastewaters. The use of conventional treatment methods along with membrane reactors and advanced posttreatment methods resulting in a hybrid wastewater treatment technology appear to be the best. The recommendations provided in this analysis will prove useful for treatment of wastewater from the pharmaceutical industry