Christian Salvesen

INTRODUCTION

The effluent treatment plant at North Thoresby provides treatment for Borehole water used in the processing of vegetables. The plant comprises of two separate activated sludge reactors. When run together the two reactors are capable of treating a maximum inlet flow of 3000m³/d with a COD loading of 9000Kg/d. The plant discharges direct to river and has to operate to strict Environment Agency consent levels for suspended solids, BOD and flow. ACWA Services Ltd provide the Management, manning and technical support required to ensure the smooth and efficient running of the effluent treatment plant.

DESCRIPTION

Process effluent from the vegetable processing plant is received at the effluent plant via a course 10mm Aqua-Guard screen into the reception pit wet well. From here it is pumped up to a 1mm rotary screen where the remaining vegetable solids are removed.

The screened effluent then gravitates to a rectangular balancing tank with a capacity of 240m³ before being pumped to one of three primary clarifiers each with a capacity of 100m³. Settled sludge from the primary clarifiers is centrifuged and removed from site for disposal to land.

Primary settled effluent from primary clarifier P1 flows into the adjacent wet well before being pumped into the activated sludge reactor No 2 for treatment, the capacity of this reactor is 2800m³. Primary settled effluent from primary clarifiers P2 and P3 flows into the adjacent wet well before being pumped into the activated sludge reactor No 1 for treatment, the capacity of this reactor is 3400m³. Both of the reactors have been fitted with anoxic zones to promote de-nitrification prior to final settlement.

During periods of high loading, most notable during the pea season, (June to September) Oxygen is supplied for aeration purposes. The Oxygen is injected into the reactors via Vitox pumps controlled by Dissolved Oxygen Probes located in each tank.

The activated sludge then gravitates to one of three clarifiers, each with a capacity of 290m³. C4 and C5 serve reactor 1 and C6 serves reactor 2. Settled activated sludge is returned to the reactor from where it originated or is stored as surplus sludge and de-watered in readiness for removal from site. Settled effluent from the clarifiers can be passed through the sand filters to further improve its quality prior to discharge to river.

Project Details

Client: Christian Salvesen, North Thorseby

Industry: Food Effluent Waste

Application: