Ostara and ACWA partner on UK wastewater nutrient recovery

  • Technology


Canadian company Ostara Nutrient Recovery Technologies Inc. and the UK’s ACWA Services have entered a technology licensing agreement to bring Ostara’s Pearl phosphorus and nitrogen recovery process to the UK market.

The process can recover nutrients from municipal and industrial wastewater streams, and the agreement targets UK water companies and operators of anaerobic digestion systems. The end result of the process is an eco-friendly fertiliser which is marketed at Crystal Green.

Ostara will supply key components under licence, and will manage the sales and marketing of the Crystal Green fertiliser. ACWA will be responsible for design, installation and commissioning of the mechanical and electrical equipment.

Wastewater streams are prone to scaling of phosphorus in the form of struvite, requiring chemical control. The Pearl process uses controlled chemical precipitation within a fluidized bed reactor to form struvite crystals. The reactor conditions are controlled to produce pellets of the required size, which are then extracted, dried and solds as the Crystal Green product.

According to the companies, the process recovers up to 85% of phosphorus, reducing chemical and maintenance costs.

Peter Brewer, UK General Manager for ACWA, commented: ‘The annual savings in chemical dosing alone for some wastewater treatment plants could be in the hundreds of thousands of pounds.’

Ostara also offers its WASSTRIP process to further enhance Pearl. According to the company, this extracts more phosphorus, almost eliminates struvite formation in the digester, reduces biosolids production by up to 25%, and reduces the ratio of phosphorus to nitrogen so that biosolids are more suitable for land application.

From ACWA’s perspective, access to Pearl complements its AMTREAT ammonia removal technology already in use in the UK.


  • UK, Ostara, ACWA Services, municipal wastewater, resource recovery, phosphates