Extracting valuable by-products from municipal sewage and re-using them in crop fertilizers and day-to-day consumer applications is gaining popularity.

Industry is already capitalising on this controversial new resource,according to experts at the world’s largest supplier of water services, Veolia Water Solutions & Technologies (Veolia).

At the company’s technical seminar recently held in Johannesburg, Laurent Schmitt, Design & Build general manager, at Veolia, discussed the concept of nutrient and product recovery with top municipal and industrial figures, “Instead of seeing municipal sewage as something that needs to be disposed of as cost-effectively as possible, we’re moving into an era where wastewater treatment plants are seen as a type of mine, where raw materials for the manufacturing of day-to-day products can be extracted in abundance, while earning revenue for the plant at the same time,” he said.“The benefits of sewer mining clearly outweigh the controversy.”

With a 20% expansion predicted for the global phosphorus commodities market by 2015, struviteprecipitation, whereby the phosphorus is extracted from municipal sludge, has largely dominated the sewer mining discussion. As one of the world’s least abundant essential nutrients, and with no synthetic substitutes available to the market, phosphorus is set to become one of the main by-products of the sewage treatment process.

“An estimated 3 million tons are available for extraction through our sanitation networks annually, which is enough to satisfy up to 20% of humanity’s current phosphorus requirement. Veolia has already proven the concept’s viability at an extraction plant in Germany, which is currently producing 730 tons a year with operating gains exceeding €50000 per annum, proving industry’s acceptance of this often controversial concept,” concluded Schmitt.