THE USE OF REED-BEDS FOR SLUDGE DRYING

This paper reviews the design and performance experience with sludge-drying reed-beds over the past fourteen years. Whilst there are very few of these systems in the UK, there is much experience in Europe and particularly in Denmark. The Danish experience is reviewed in some detail. The design of and experience gained from two UK systems is described. The final dry-solids concentration depends upon the concentration in the initial sludge dose. It is possible, when treating anaerobically digested sludges containing 3–4% DS, to achieve about 90% volume reduction and a final dry-solids content of up to 40%. With thinner activated sludges containing 0.3–0.6% DS, a reduction (in volume) of greater than 97% is possible with a final solids concentration in the range 10–20%.