SH+E Groupstarted the construction of an Airprex unit at the waste water treatment plant Amsterdam-West, the Netherlands. The wwtp is operated by the city's waterutility company Waternet who already digests its activated sludge forconversion to biogas. Early next year when the Airprex unit is ready, alsovaluable phosphate will be recovered from the sludge.

SH+E placedthree recovery reactors that will produce 1,000 tonmagnesium-ammonium-phosphate fertilizer (MAP) annually. This will be Europe'slargest phosphate recovery at a municipal waste water treatment plant.

Double benefits
At the Amsterdam treatment works, currently phosphate is removed from the wastewater by utilizing a biological P-removal process. By this process thephosphate is accumulating in the treatment work’s sludge’s and causingsignificant operational problems due to struvite blocking in pipelines, pumpsand other treatment machinery. The new phosphate recovery unit will removephosphate from the waste sludge streams and so eliminating the cost expensiveblocking of various equipment.

Waternet isbenefitting in two directions: elimination of cost expensive repair works aswell the production of a valuable magnesium -ammonium -phosphate fertilizer(MAP).

The AirPrex unitadds air (CO2 stripping) and magnesium chloride to the digested sludge. Theformed struvite (MAP) is intermittently tapped from the conical reactor bottom

Running out ofphosphate rock
Most of the phosphorus used in fertilizer comes from phosphate rock, a finiteresource formed over millions of years in the earth’s crust. Ninety percent ofthe world’s mined phosphate rock from e.g. Marocco and China, is used inagriculture and food production, mostly as fertilizer.

The expectationis that within 50 years the worlds natural resources of phosphor are exhausted.

This urges thenecessity to re-use the valuable phosphorus as much as possible, taking thegrowing world population into account.

Currentlychanges in Dutch law and regulations are undertaken to allow recycled phosphatebeing used for the production of commercial fertilizers.

Airprex-technology
SH+E Group provided Waternet with the Best Economic Offer during a publictendering procedure. The Airprex-technology applied is licenced to the SH+EGroup. Recently projects with the Airprex-technology were realized by SH+E inGermany and at the Dutch wastewater treatment plant Echten.

Recently theSH+E Group secured a new contract for the transformation of the Dutch Amersfoorttreatment works into an energy and fertilizer producing wastewater treatmentplant by the year 2015.

(read more on this website: Waterboard Vallei & Veluwe startsconstruction energy and nutrient facility at WWTP Amersfoort, the Netherlands,8 September 2013)