Vinesh V. Rakholiya and S. A. Puranik
Modern environmental legislation is becoming much more internationally coherent and less prescriptive, and focused on prevention of pollution through control of hazardous materials and processes as well as on protection of eco-systems. Active Pharmaceutical Intermediates from waste water streams of API companies are emerging contaminants in the aquatic environment, because of their adverse effect on aquatic life and humans. These contaminants are high in COD and difficult to treat biologically. A number of technologies have been developed over the years to remove organic matter from industrial wastewater. The most important technologies include coagulation/flocculation process, membrane filtration, and oxidation process. These methods are generally expensive, complicated, time consuming and requires skilled personnel. The high cost of coal-based activated carbons has stimulated the search for cheaper alternatives. Low cost and non-conventional adsorbents like activated carbon, Lignite, Fly ash, Neem tree leaves are used as a adsorbents for removing COD of Industrial waste water. Activated carbon is a commonly used adsorbent in sugar refining, chemical and pharmaceutical industries, and water and wastewater treatment. Increasing requirements for clearer and more polished effluent from many processes suggest that, barring the development of new technologies, industrial need for activated carbon will only increase in future. Fly ash has shown quite effective adsorbent capacity for COD reduction from the Industrial wastewater. Though its capacity is lower than that of commercial grade activated carbon, the low material cost makes it an attractive option for the treatment of Industrial waste water which contains phenolic compounds. The study aims at demonstrating that adsorption as the first stage of treatment increases efficiency of the subsequent biological treatment. Experiments are carried out on different wastewater samples from chemical plants on adsorbents viz. activated carbon, bentonite, and lignite. The effectiveness of adsorbents in the removal of refractory organics by way of reducing chemical oxygen demand and colour is evaluated. The results of COD reduction are fitted into different models available in literature including the new model Rathi Puranik equation, which requires least experimentation for predicting COD values
