With restrictions on the quantity and quality of wastewater that treatment plants can release into rivers, lakes and the sea, contemporary water based sanitation systems are left with huge amounts of sewer sludge. Whether incinerated or spread on agricultural land, sludge compromises air quality.
EPA Air Toxics Website has a page on Sewage Sludge Incinerators with complete information on rules, standards of performance, and emissions guidelines.
Wastewater Systems This industry site was designed to assist novices and experts alike to understand wastewater treatment system technology. It gives an excellent breakdown of components and processes, including sludge incineration.
See also PHLUSH Sewage Sludge page.