SUBSCRIBE to our eNews and SCOPE Newsletter


Read earlier SCOPE and eNews editions.

Process & contact

Members of ESPP / DPP

Phosphogreen (Suez).
Phosforce (Veolia)

Input materials

Only applicable to WWTPs operating biological P removal (EBPR), usually with sludge digestion (AD).

Output products

Struvite, useable directly as a fertilizer or in blended products.

Has added value as a slow-release, low leaching, non root-burning fertiliser.

Over 50 studies show that struvite is plant available an effective fertiliser (see SCOPE Newsletters n°s 43, 121, 122)

EU Fertilising Products Regulation criteria for recovered struvite proposed are under finalisation (see final STRUBIAS report Sept. 2019).

Recovered struvite already has End-of-Waste status and EU 2003/2003 fertiliser validation in a number of countries.12strue

Process description

Sludge return streams or sidestreams in the biological treatment process are adapted to optimise soluble orthophosphorus release and to increase P available for struvite precipitation, enabling recovery of 20 – 35 % of sewage works inflow P as struvite. This rate can be further increased to 45 – 50 % by processes which hydrolyse sewage sludge to render the phosphorus soluble (see “Sludge lysis” in this Catalogue)

Operating status

Ostara WASSTRIP (Crystal Green) is operating at 12 WWTPs worldwide, recovering 45 – 50% of WWTP inflow P.

Phosphogreen at Aarhus Åby, 70 000 p.e. since 2013: 45-50% recovery of WWTP inflow P is achieved so long as ferric dosing is not required in WWTP operation.

NuReSys (Apeldoorn Hybrid Unit): 30% recovery of WWTP inflow P.

Veolia Phosphogreen: pilot scale trials at 3 sites, demonstration scale planned

Parforce: under construction (early 2022) at Wolfsburg, Germany, 150 000 p.e. (photo) up to 60 – 70% recovery of WWTP inflow P by struvite precipitation from hydrolysed sludge.

SUBSCRIBE to our eNews and SCOPE Newsletter


Read earlier SCOPE and eNews editions.