Possible Uses for Sludge from Drinking Water Treatment Plants

Sludge from drinking water treatment plants is usually disposed of in landfill sites as nonhazardous waste. However, a review of the legislation at European, Spanish, and regional levels identifies uncertainty regarding this type of waste. For example, it is unclear whether the drinking water sludge can be sent to inert landfill sites, which would be less expensive, or whether it could be reused for other purposes. According to Article 5 of Spanish Law 22/2011 on waste and contaminated soil, various physicochemical and biological parameters must be determined before alternative uses can be established. At present, sludge from drinking water treatment plants is wrongly associated with sludge from wastewater treatment plants. In this study, parameters of the sludge produced in drinking water treatment plants that may lead to a new waste status for the same are analyzed. The principal problems that may limit its reuse are its low organic matter and high silica contents.