Sewage Sludge Disposal

Sludge is organic matter which settles down in primary and secondary sedimentation tanks. Sludge typically comes from a few sources:

1. Domestic Sewage
2. Industrial Sewage
3. Water Treatment Plants

Sludge treatment is focused on reducing sludge weight and volume to reduce disposal costs, and on reducing potential health risks of disposal options. Water removal is the primary means of weight and volume reduction, while pathogen destruction is frequently accomplished through heating by means of thermophilic digestion, composting, or incineration. The choice of a sludge treatment method depends on the volume of sludge generated, and comparison of treatment costs required for available disposal options.

There are several types of sludge as well:

1. Humus Sludge - the product of settlement of effluent and is mainly bacterial and fungal material sloughed from the filter media.
2. Activated Sludge - aerated sewage containing aerobic bacteria and protozoa that help break it down.
3. Digested Sludge - after going through a biological process of decomposition, pathogens are destroyed and the total mass is reduced, digested sludge has the appearance and characteristics of rich potting soil.

Sludge may include toxic chemicals removed from liquid sewage, and reducing sludge volume may increase the concentration of some of these toxic chemicals in the sludge. When disposing of sludge, it is important to work with a waste company that specifically mentions the capabilities of dealing with sludge treatment and disposal.