Water & Wastewater Treatment

WWT March 2020

Water & Wastewater Treatment Magazine

Issue link: https://fhpublishing.uberflip.com/i/1212582

Contents of this Issue


Page 26 of 35

www.wwtonline.co.uk | WWT | MARCH 2020 | 27 of digestate. To combat this, struvite can be recovered from the digestate by increasing the pH and adding magnesium to precipitate out the struvite which can then be processed into pellets and sold as an inorganic fertiliser. Ammonia stripping – this has the dual benefit of remov- ing ammonia from the diges- tate, which reduces the risk of volatilisation during storage, and producing ammonium sulphate or ammonium nitrate which can be used as a liquid fertiliser. Ammonia is removed from the digestate liquor by mixing it with air at high temperature and high pH. The ammonia gas is then scrubbed with sulphuric or nitric acid to produce an ammonium salt which can be used as a nitrogen-rich fertiliser. Ion exchange – liquid di- gestate can be passed through a column containing adsorp- tion media such as zeolite or an ion exchange resin to remove ammonia from the di- gestate. The resin can then be regenerated, and an ammonia- rich liquid drained off. This liquid has potential for use in the chemical production industry. A number of "second- generation" technologies are emerging that may offer further opportunities for pro- duction of valuable resources. Many of the technologies are based on the manipulation (Source: Agler et al. 2011)

Articles in this issue

Links on this page

Archives of this issue

view archives of Water & Wastewater Treatment - WWT March 2020