Nigg Bay

Nigg Bay was the first UK wastewater Volute Dewatering Press instillation, installed on the north east coast of Scotland near Aberdeen. This is significantly large installation as the PE of the works serves 250,000 people, therefore the sludge dewatering technology needs to be able to process large enough volumes and be reliable for future demands.

Kelda Water Services Grampian (KWS Grampian) has a 28 year design, build, finance and operate contract with Scottish Water to operate and maintain four wastewater treatment plants serving the north east of Scotland; two sites in Aberdeen (Nigg and Persley) and two sites to the north (Peterhead and Fraserburgh). In addition to
treating wastewater, KWS Grampian operate sludge treatment facilities able to receive imported sludge and liquid wastes.

The order placed with Evergreen Water Solutions was for the design, manufacture, testing, inspection, delivery, commissioning, training and handover of 2 (No.) Amcon Europe ES354 Volute dewatering presses. This included the provision of mixing and flocculation tanks and any necessary modifications to both the feed and reject pipework and the cake discharge arrangement to suit the existing cake pumps. Evergreen Water Solutions were also responsible for ensuring that their PLC system was compatible with that of KWS
Grampian and providing a control philosophy for maintaining the required dry solids concentration of the sludge cake product as part of the PLC control. As it was absolutely essential that such a major asset should have minimal downtime during the install.

The 2 (No.) Volute units operate at a range of 35-70m3/hour (duty/ standby or duty/assist). The Nigg Sludge Treatment Centre treats the equivalent of 300,000m3 and 400,000m3 of sludge per annum, equivalent to the processing of between 8,000 and 10,000T of dry solids. As expected solids capture is excellent at around 98%, which usually results in a filtrate containing around 600mg/l of suspended solids