Digesters at water treatment facilities kill pathogens.

Before treatment, wastewater may contain disease-causing microscopic organisms, such as bacteria and viruses, which are known as pathogens, or germs.

Federal law requires treatment to reduce pathogens: Digesters and other forms of treatment kill from 90 to 99.5 percent of the pathogens originally found in wastewater solids, which allow biosolids to be safely applied to agricultural and forestlands. Additional treatment by heating and/or composting can create a product that is used in home gardens and landscapes.

The environmental cleaning process: After land application, natural environmental conditions such as exposure to sunlight, lack of moisture and a relatively harsh soil environment destroy nearly all of the few remaining pathogens that may exist in biosolids.