A major UK vegetable processor with seasonal operation and intermittent high flows, chemical oxygen demand (COD) and total suspended solids (TSS).


The site had significant Mogden Charges (> £1 million pa) and issues with high costs from sludge handling and disposal, including significant tankering charges to remove DAF sludge from site.


– Rotary Screen to remove particles > 1mm

– Balance tank to handle peaks and troughs of daily production to allow a consistent flow of effluent to the DAF (Dissolved Air Flotation)

– Automatic pH correction and monitoring system to ensure pH of effluent reaching the DAF would allow efficient functioning of the coagulation and flocculation system

– Installation of a Dissolved Air Flotation (DAF) system using coagulant and anionic powder polymer via an automatic chemical dosing system

– A Decanter Centrifuge using a cationic emulsion polymer was installed to dewater the sludge coming off the DAF, reducing the volume of sludge to be removed from site

Project Conclusion Statistics


reduction in discharge costs (Mogden bill)


reduction in sludge disposal costs


compliant with discharge parameters