Ashford Wastewater Treatment Works – Amtreat® Ammonia Removal

With Southern Water’s decision to upgrade Ashford WwTW and sludge Treatment Centre to include sludge dewatering, thickening and drying systems. These additional processes produced additional hot and cold sludge liquor flows which needed to be treated before returning the flow to the head of the existing treatment works.

ACWA’s successful solution was to design and construct twin proprietary high rate (Amtreat®) ammonia removal systems along with a hot & cold liquor blending system to help regulate the temperature within the Reactors. The system was built to provide process flexibility with regular variance in heat and load due to upstream processes on line status.

The Amtreat® system comprises of a hot effluent regulator system feeding twin streams consisting of an anoxic tank feeding an Amtreat® Reactor with a degassing column and Final settlement tank along with recirculation, and chemical dosing systems.

This Amtreat® system was the second installed in the UK, which treats high strength ammonia sludge liquors, to date there are seven plants installed for various municipal companies such are for Anglian Water, Severn Trent Water and United Utilities.

Technical Overview

Design basis:

Description   Unit        Feed        Discharge

Flow             m3/d 1200-2100   1200-2100

BOD              mg/l        650              <200

NH3-N          mg/l     850-900         <50

TSS               mg/l       1,750           <200

Temp (Combined) oC        20-33 

The Benefits

ACWA’s Amtreat® solution provides:

  • High ammonia removal efficiencies in excess of 98%
  • A very reliable and robust process
  • Reduced capital and Whole Life Costs
  • Flexible plant arrangement
  • Can utilise existing assets if available
  • Simple to operate and maintain