Proceedings

A predictive model to determine ammonium levels in digestate liquors

Smyth, M.1, Brookes, A.2, Riches, S., Bungay, S.3

1Aqua Enviro, UK, 2Anglian Water, UK, 3Helix ECL, UK

 

(free)

Abstract

Anaerobic digestion (AD) involves the sequential breakdown of organics into (principally) methane and carbon dioxide.  Nitrogen is largely preserved in AD, however a proportion is transformed from organically bound nitrogen to ammonium nitrogen.  The degree of transformation will directly influence ammonium-N levels in the digestate, return liquors post-dewatering, and ultimately the ability of the activated sludge plant to meet its ammonia consent.  Quantifying ammonification is therefore important to water companies and will influence the decision making process in new build schemes and plant upgrades.  Operationally, where high ammonium levels are challenging to either liquor treatment or digester operation, nitrogen sources can be mapped through the process and changes to plant operation made.  Operational changes can include relocation of sludge imports, reduction in digester throughput, reduced dwell time in primary tanks and increasing the sludge age.

 

This paper details the steps needed to develop a predictive excel-based tool for digester ammonium-N levels.  The model takes into account the total nitrogen content of the feed sludge, dry solids content, proportion of readily available nitrogen and the rate of volatile solids destruction.  It draws upon data from an Anglian Water study at four sites, which have been used to calibrate and refine the model.

 

 

Acknowledgements

Thanks go to Anglian Water for their co-operation on the project and sharing the data.  Secondly to Helix ECL, where the model was first developed and subsequently evolved with Aqua Enviro.

 

Key Words

Keywords: ammonia, anaerobic digestion, liquor treatment, total nitrogen, volatile solids destruction

 

Please fill in your details to download the proceedings



For more information about how Aqua Enviro
can help you, contact us...

8 Appleton Court, Calder Park, Wakefield, WF2 7AR, UK

Consultancy and Laboratory services: + 44 (0)1924 242255

Conferences and Training enquiries: +44 (0)1924 257891

Email: enquiries@aquaenviro.co.uk

  • By submitting this form, you agree that we may use the data you provide to contact you with information related to your request/submission and other relevant Aqua Enviro services. You can unsubscribe from Aqua Enviro marketing emails at any time by clicking the unsubscribe link in the email. To learn more, see our Privacy Policy