Removal of heavy metal from casting sand in valve manufacturing industry through bioremediation technique

Abstract

In India, the metal casting industry has been catering to a large market including agriculture and forestry, and the automotive industry for casting of engines, accessories, and international export. Consequently, there are enormous amounts of sand being removed from the casting cycle. To prevent further damage to the environment caused by disposal of this sand, more efficient and environment friendly methods should be adopted. This sand has found reuse in a wide range of applications ranging from agriculture to construction. Use of foundry sand in these fields has proved to be beneficial in waste disposal, in energy saving and so on. Foundry sand is a by-product from the ferrous and nonferrous metal casting industry. Foundry sand obtained from the latter has been found to contain heavy metals. Most heavy metals are well-known carcinogenic agents and pose a hazardous impact to life and hence must be treated to permissible limits. Bacterial methods involving the use of bacteria such as Bacillus have proved to be effective in the treatment of heavy metals such as aluminum and nickel present by reducing their concentration from as much as 50 % up to 90 %.