TREATMENT OF COAL HANDLING WASTEWATERS CONTAINING CYANIDE AND PHENOL

Abstract

Cyanide and Phenol are of the most toxic pollutant in the environment. They disturb ecosystem and affect the health of human beings in many ways. They are released, both simultaneously and individually from many industrial effluents. Coal handling effluents have been found to contain both cyanide and phenol and treatment of these effluents is of primary importance. Phenols and cyanides can be recovered as well as removed from the wastewater streams using various physico-chemical and biological techniques practiced commercially. Lack of complete mineralization, cost effectively and release of secondary byproducts are amongst a few major causes that limits the installation of many such processes. Moreover, co-removal of cyanide and phenol from industrial wastewater is challenging. Of these, the techniques of adsorption and biodegradation have gained a lot of popularity in the recent past as they are cost effective and environmental friendly. Using the above information, the present investigation is planned to club the techniques of adsorption and biodegradation and check the effectiveness of this technique for treatment of coal handling wastewaters. The investigations were performed on synthetic simulated wastewaters containing cyanide and phenol. Granular Activated Carbon (GAC) was selected for adsorption process. Batch experiments were conducted to study the effectiveness of adsorption. Characterization of adsorbent was carried out using various techniques such as FTIR, Elemental Analysis, SEM, TGA etc. The various process parameters like pH, temperature, contact time and adsorbent dose have been optimized for simultaneous adsorption of cyanide and phenol. To facilitate mathematical modeling, adsorption kinetic models and isotherm models of single and binary component systems have been developed. Two micro organisms, Pseudomonas putida (MTCC 1194) and Azorobacter Chroococcum (MTCC 446), obtained from MTCC Chandigarh, were used for study of biodegradation of cyanide and phenol. They were found to be effective for simultaneous biodegradation of cyanide and phenol. Simultaneous Adsorption and Biodegradation (SAB) studies were conducted by combining both the above processes. Experimental results showed that the cyanide and phenol removal efficiency of SAB is higher than that of adsorption or biodegradation alone.