CHEMICAL WASTE MANAGEMENT

Chemical Waste Management

Abstract



There is growing environmental concern with the methods of waste disposal used for handling hazardous materials in the metal finishing industry. A resulting need exists to develop and implement the best existing and potential technologies for waste minimization and resource recovery. The objectives of this study were to identify and briefly describe both existing and potential future methods of waste management for minimizing and recovering metallic wastes in the metal finishing industries, including evaluation of the advantages and disadvantages of the various methods available and being developed. 

Chemical Waste Management

Introduction

 Electroplating of metals became feasible in 1840 and has grown until it now ranks as an important specialty industry, with nickel, copper, and chromium as examples of the most important plating metals. Electrodeposited metals serve either a decorative or structural purpose, or sometimes both, by providing a pleasing appearance and/or various desirable engineering properties. Electroplating finds application in many areas, including electronic, automotive, aerospace, and household products. An example of this dual purpose application is chromium plating, which has both decorative and “hard” or industrial-use. These hard chromium coatings possess such desirable engineering properties as heat, wear, corrosion and erosion resistance, and a low coefficient of friction . Chromium is deposited primarily from a chromic acid (CrOs as HzCrOl) solution, which is highly toxic(MacNeil McCoy 2009 p. 691). A major concern in metal electroplating is the high toxicity of plating chemicals and, therefore, the process requires extensive measures to prevent release of hazardous material to the environment. Releases come primarily from discharge of improperly treated rinsewater, though spray from the plating bath surface (particularly while using aeration for mixing), spills, and occasional plating bath disposal (because of uncorrectable composition) can also be of concern. In addition, since chemical precipitation of heavy metals is the primary method of treatment of these waste materials, disposal of hydroxide sludge is a significant problem. When confronting these problems, concern must include the short and long-term effects on the health of the plating shop workers and the public in general. Concern for public safety has lead to growing environmental regulations on the federal, state, and municipal levels. Regulations include the Resource Conservation and Recovery Act (RCRA) and the Hazardous and Solid Waste Amendments of 1984. As with all manufactures, the plating industry must deal with unfounded fears of the public about anything involving chemicals, especially when the chemicals are deemed “toxic” by public institutions, such as the government or the press. To command public confidence, not only must we continue to responsibly handle these hazardous materials, but we must make our successes known to the public, which, at a technical level, will involve developing improved means for disposal and ultimately recovery of valuable resources through process improvements and new technologies. The minimization, recovery, and treatment methods employed for wastes produced by any electroplating process, however, can be very complicated. The subject is an area of chemical engineering, involving chemical reactions (both chemical and electrochemical) and unit operations (such as mixing and filtration), typically referred to as electrochemical engineering. Developing feasible solutions must involve full consideration of all technical, legal, and economic implications(Aguwa Hass 2009 p. 641. ). 

Aims and objective

The aims of this report were to identify and briefly describe ...