News

Dirk European Holdings Ltd., Birkenhead,  have recently won the order to supply an RDP Rhenitherm Pasteurisation System to provide Class A quality biosolids products at Girvan Wastewater Treatment Works in West Scotland. The works have been designed for a 55,000 population equivalent and consist of primary, partial secondary and sludge treatment stages. The Rhenitherm Pasteurisation system will produce Class A friable material with low lime content from the dewatered sludges of two centrifuges processing waste sludges from an SBR plant together with other mixed sludges.

The plant will pasteurise an average 4,000 kg/day sludge cake with a dry solids content of 20 ± 2%. Ambient sludge temperature is expected to be between 7 – 22°C. In order to cope with potential changes in legislation, the pasteurisation plant has been designed to heat the sludge at 55°C for two hours or 70°C for half an hour. The system was chosen since it was the only one which could provide a safe biosolids product with a low lime dose whilst making a soil-like material at a low dry solids content. This has been necessary due to the nature of the surrounding land which is sensitive to high lime doses. The land will be used to grow potatoes. The pasteurisation plant is due to come on line mid next year.