ABSTRACT
The non-biological sludge stabilisation comprises the physical and chemical methods, which are used to achieve oxidation of volatile substances present in sludge and to inhibit its potential for putrefaction. Thermal treatment essentially serves as both a stabilisation process and conditioning process. The thermal treatment coagulates the solids, breaks down the gel structure, and reduces the water affinity of sludge solids. The thermal treatment process is most applicable to biological sludges that may be difficult to stabilise or condition by other means. The alkaline stabilisation of sludge is achieved by using the hydrated lime, quicklime, flyash, lime and cement kiln dust, and carbide lime. Lime addition to untreated sludge has been practised for many years as a conditioning process to facilitate dewatering. Sludge treatment with lime provides a low pH condition into the sludge, which ceases the microbial growths that are responsible for odorous gases generation.
