Dairy Crest Davidstow Wastewater Treatment Plant

Dairy Crest recently undertook an expansion project at their Dairy Crest Creamery site at Davidstow, Cornwall to upgrade and extend the existing WwTP to double treatment volume and organic load.  Doran Consulting were appointed by WIS Ltd to assess options and project manage the delivery of their construction contract.  We provided planning drawings, Civil Design, Structural Design, advice on Site surveys and investigations and provided HAZOP Facilitator services for the WwTW and at the main creamery extension.

The new plant treats a PE of 145,000 to 13mg/L BOD; 20mg/L suspended solids and 5mg/L ammonia and consists of a complete new treatment plant for BOD removal upstream of the original plant which now polishes and denitrifies the wastewater with partial recovery for re-use at the creamery.

Increased hydraulic and biological capacity required our re-appraisal of the initial design.  We proposed circular tanks to accommodate the increased volume and the use of "triton" surface aerators for better process efficiency in deeper liquid.  We rearranged the layout of process tanks away from existing tanks to avoid sheet piling and added value by extensive reuse of assets & containerised equipment.

Critical process elements include a new RBC unit for domestic sewage; new chemical resistant pipelines from the creamery; preliminary treatment including grease removal; divert tanks; balancing tanks; de-nitrification and sludge conditioning within 2 anoxic tanks upstream of secondary (nitrifying) biological stage; secondary treatment in 2-stages of aeration tanks and settlement tanks; sludge storage and thickening.