In a scheme to improve water treatment at the Skipton works, and as part of a current framework agreement with Yorkshire Water, 2H Water Technologies supplied and installed 3030m3 of BIOdek® 190.60 plastic cross-flow structured media (150m2/m3 specific surface area) in three secondary trickling filters at the plant.
Each tank was 16.5m in diameter with a packed media depth of 4.8m. The media was placed in concrete tanks with a sidewall 1100mm above the media. This ensured safe movement at the top of the filter, and offered wind protection for the distributor, which prevented spray being blown off the filter.
This filter depth required under-ventilated media. The plenum area beneath the pack was served by ventilation slots around the periphery of the tank. Doors were fitted to the vents for use in very cold weather.
The distribution of liquor over the media in each filter was achieved using a four-arm tubular distributor, complete with splash plates and speed controlled by a motor drive unit.
The filters were designed to treat 767kg/day of settled BOD, and 168kg/day of ammonia. It achieved a final effluent compliance of 50:35:15mg/l (SS:BOD:ammonia).