ABSTRACT
Sludge is universally considered as waste, something to be disposed of out of sight and out of mind. As a result, the word “sludge” is usually associated with pollution, contamination and disease. Sludge can be regarded as consisting of particles aggregated into flocs that act hydrodynamically as single particles. In terms of the quantity of sludge, overall sludge production is dependent on influent loading, type of treatment, treatment performance, type of sludge-handling facilities, and effluent treatment requirements. In general, sludge production is expected to be directly related to the average dry-weather flow rate through the plant, assuming no changes in influent unit loading or the treatment process. Sludge has several sources, namely, water treatment plants, municipal waste water treatment plants and industrial effluent treatment plants. Industrial waste water treatment facilities generate different types of sludge, which can be generally classified as either organic or inorganic, and both may contain toxic materials, mainly heavy metals.
