Project

The existing effluent treatment plant at ACC's dairy in Blaydon, comprising chemical dosing, dissolved air flotation and biological filtration, failed to meet revised consent limits and ACC wished to improve effluent quality to a level which would meet possible future tightening of consent limits. Wimpey were contracted to refurbish and supplement the existing plant to treat 20m³ /h of dairy effluent to meet the following consent limits:

Responsibilities

Front End Engineering Design comprising process selection process flow diagram, P&ID, process design calculations, equipment specification, tender evaluation and liaison with construction and commissioning.

Effluent, which is generally alkaline, is collected in a balancing tank with options for mixing with air and/or flue gas, the latter providing initial pH reduction. It is then pumped to a treatment process comprising fully automatic chemical dosing, dissolved air flotation for protein separation, first stage biological filtration with nutrient addition, settlement, second stage biological filtration and final settlement prior to river discharge.

Much of the original plant, including the dissolved air flotation and first stage biological filter, was refurbished and incorporated into the final scheme.