Journal of Energy Technologies and Policy www.iiste.org ISSN 2224-3232 (Paper) ISSN 2225-0573 (Online) Vol.3, No.11, 2013 – Special Issue for International Conference on Energy, Environment and Sustainable Economy (EESE 2013) 84 EESE-2013 is organised by International Society for Commerce, Industry & Engineering. Electrochemical Treatment of Hazardous Organic Pollutants – A Status Review Himadri R. Ghatak Chemical Technology Department, Sant Longowal Institute of Engineering & Technology, Longowal-148106, Punjab, India *Email address of corresponding author: h_r_ghatak@yahoo.com Abstract The rapid industrial development, while giving a significant boost to the quality of human life, has also taken a heavy toll on our environment. One of the manifest effects is the proliferation of hazardous organic pollutants in the environment. These pollutants have many environmental and health implications like persistence and biomagnification, mutagenic and carcinogenic nature, endocrine disruption, and ecotoxicity to name a few. Being mostly non-biodegradable or biorecalcitrant, they cannot be effectively treated with biological wastewater treatment methods. Physical separation methods only shift the pollutants from one stream to the other pending a final disposal. Advanced treatment techniques are, therefore, needed to deal with such pollutants. Against this backdrop, the electrochemical treatment methods are significant and relevant. Electrocoagulation utilizes a sacrificial anode, often iron or aluminium, for the in-situ generation of Fe(III) or Al(III) ions as the coagulationg agent. This method has been found to be partially successful in the remediation of wastewater containing hazardous organic pollutants. But the most important of the electrochemical treatment methods is fast emerging technique of Electrochemical Advanced Oxidation, also known as Electrochemical Incineration. This aims at mineralization of the target pollutant by generating highly reactive hydroxyl radicals at the anode through dissociation of the water molecule. Certain pollutants also undergo direct oxidation at the anode through electrochemical charge transfer. The anode material, the inter-electrode potential, current density, and the supporting electrolyte have all been found to affect the process. Hydrogen is generated at the cathode which further adds to the attractiveness of the process. Keywords: Hazardous organic pollutants, electrochemical incineration, electrocoagulation, anode material 1. Introduction Today synthetic organic chemicals are ubiquitous and make their presence felt in almost every walk of life. While these chemicals have several advantageous characteristics one cannot wish away their darker side too. They often pose potential threat to the environment after their immediate intended use. These substances can be toxic and persistent. Many of them show bioaccumulation through the food web. Quite a few organic substances have been found to be mutagens and carcinogens and some are endocrine disruptors. In recognition of the environmental implications of these substances the International conventions and government regulatory authorities of most of the countries have included them in their priority lists. The objective of the Stockholm Convention on Persistent Organic Pollutants is to ‘protect human health and the environment from persistent organic pollutants’ (Stockholm Convention, 2001). It lists 26 regulated organic chemicals and 5 more chemicals/chemical classes are under review for possible inclusion. Concise International Chemical Assessment Documents (CICADs) from International Programme on Chemical Safety lists about 60 odd organic chemicals with associated environmental issues (CICADS, IPCS). The United States Environmental Protection Agency (USEPA) under its National Waste Minimization Program provides a list of 31 priority chemicals, 28 of which are organic chemicals (USEPA, Priority Chemicals). The listed organic chemicals are persistent, bioaccumulative, and toxic (PBT). Environment Canada has provided two Priority Substances Lists containing 34 and 16 organic chemicals, respectively, many of which are conclusivey proven to be toxic (Environment Canada, PSL1 1989, PSL2 1995). In 1993, the Council of the European Communities adopted Council Regulation 793/93/EEC, thereby introducing a comprehensive framework for the evaluation and control of ‘existing’ chemical substances (EC, 1993). All but two of the 41 substances listed in the Priority Lists published from time to time are organic chemicals. The Manufacture, Storage and Import of Hazardous Chemical (Amendment) Rules, 2000, of the Ministry of Environment and Forests, Government of India, regulate the use of 94 toxic organic chemicals (MoEF, GOI, 2000). The priority chemicals list of 28 substances promulgated by The Environmental Management Bureau of Phillipines includes 18 organic chemicals