Struvite formation in wastewater treatment plants: Opportunities for nutrient recovery

Nutrient removal from wastewater discharges is an increasing challenge for water authorities, as regulatory authorities tighten discharge standards to avoid eutrophication problems in receiving waters. Significant costs are associated with the extra treatment processes required to meet these new discharge standards. The most widely used technologies for nutrient removal include biological nitrification/denitrification for nitrogen removal and metal salt precipitation for phosphorus removal. Both approaches result in the nutrient being made unrecoverable for possible use as a fertiliser. An alternative to these conventional technologies which can provide for recovery of the nutrient as a commercial fertiliser could be the production of magnesium ammonium phosphate (struvite).