Steen Nielsen
Orbicon A/S
The Nordborg Sludge Reed Bed System was established and planted with reeds in September 2003. The Reed Bed System has a capacity of 350 TDS per year and consists of 10 basins, each having an area of approx. 705 m2 at the filter surface and a maximum area-loading rate of 50 kg DS/m2/year. Sludge production from the WWTP consists of activated sludge (SAS) directly from the activated sludge plant and digested sludge from a mesophil digester. The two sludge types are mixed before being added to the Reed Bed System. 90 – 120 m3 (approx. 0.5 % ds.) of SAS is mix with 3-6 m3 of digested sludge (approx. 2-3 % ds). Finally, the batch is diluted with effluent from the WWTP to a final volume of 140-160 m3. The system’s loading regime consists of applications of approximately 140-160 m3 of sludge (approx. 0.6-08 % ds.) once daily. From 2006, each basin was subjected to a loading quota of 600 m3 over a period of approximately 4 days. Loading was followed by a 36-64 rest period. Because of the increasing sludge production the area-specific loading rate has increased from approximately 17 kg DS/m2 /year in 2004 to 44 kg DS/m2 /year in 2006. KEY WORDS Dewatering, Digested, Drying, Loading, Reed Beds, Surplus Activated Sludge, Treatment.
Aqua Enviro Ltd
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