Skip to main content

Nutrient Recovery by Struvite Crystallization Process: Virginia Experience

Buy Article:

$17.50 plus tax (Refund Policy)

Or sign up for a free trial

Abstract:

The Hampton Roads Sanitation District's (HRSD), Nansemond Treatment plant (NTP) services the cities of Chesapeake, Portsmouth and Suffolk, Virginia. The plants treated effluent is discharged into the Chesapeake Bay watershed. The NTP was designed as a 30 MGD biological nutrient removal (BNR) plant with seasonal nitrification and utilizes anaerobic digestion for solids stabilization and centrifugation for dewatering. Centrate containing high levels of phosphorus (up to 900 mg P/L) and ammonia (∼700 mg N/L) is returned to the plant headwork and contributes significantly to the BNR process loading. The high loading of these nutrients is a potential cause of instability to the treatment process leading to spikes in the secondary effluent phosphorus concentrations as well as reducing plant nitrification and denitrification capacities. During these periods, metal salts (FeCl3) have been intermittently required to precipitate phosphorus to achieve compliance. Precipitating phosphorus is quite effective, but this option is not considered as a sustainable solution for phosphorus removal due to the high costs of chemicals, solids handling and disposal.

The formation of struvite (MgNH4PO4 ยท 6H2O) has recently been commercialized as a treatment process for phosphorous and ammonia recovery from sludge dewatering sidestream and is being considered for treating centrate at the NTP. A pilot scale struvite crystallization process (Ostara Nutrient Recovery Technologies Inc.) has been operating at the NTP from October 2006 to March 2007 to determine the feasibility of the process for full scale implementation at this site. Centrate fed to the pilot reactor typically measures 300-700 mg/L phosphate-P and 820 mg/L ammonia-N. Over the course of the pilot demonstration, phosphorous removal averaged 85% while ammonia removal ranged from 35 to 50%. A full scale struvite recovery process, currently being evaluated, would reduce loading in the main liquid process train by approximately 500 lbs PO4-P/day and 250 lbs NH4-N/day in addition to providing diurnal centrate flow equalization.

Keywords: CRYSTALLIZATION; FLUIDIZED BED REACTOR; NUTRIENT RECOVERY; STRUVITE

Document Type: Research Article

DOI: https://doi.org/10.2175/193864707786831408

Publication date: 2007-10-01

More about this publication?
  • Proceedings of the Water Environment Federation is an archive of papers published in the proceedings of the annual Water Environment Federation® Technical Exhibition and Conference (WEFTEC® ) and specialty conferences held since the year 2000. These proceedings are not peer reviewed.

    A subscription to the Proceedings of the Water Environment Federation includes access to most papers presented at the annual WEF Technical Exhibition and Conference (WEFTEC) and other conferences held since 2000. Subscription access begins 12 months after the event and is valid for 12 months from month of purchase. A subscription to the Proceedings of the Water Environment Federation is included in Water Environment Federation (WEF) membership.

    WEF Members: Sign in (right panel) with your IngentaConnect user name and password to receive complimentary access. Access begins 12 months after the conference or event
  • Subscribe to this Title
  • Membership Information
  • About WEF Proceedings
  • WEFTEC Conference Information
  • Learn about the many other WEF member benefits and join today
  • Ingenta Connect is not responsible for the content or availability of external websites
  • Access Key
  • Free content
  • Partial Free content
  • New content
  • Open access content
  • Partial Open access content
  • Subscribed content
  • Partial Subscribed content
  • Free trial content
Cookie Policy
X
Cookie Policy
Ingenta Connect website makes use of cookies so as to keep track of data that you have filled in. I am Happy with this Find out more