AERATION BY DESTRATIFICATION: A TECHNIQUE FOR RESTORING THE WATER QUALITY OF LAKES AND RESERVOIRS
Lake and reservoir eutrophication is a complex process involving a variety of factors which are difficult to act upon simultaneously. The process is triggered off and perpetuated by nutriment inputs from the drainage basin. These may come into play at a later stage however, when the water body stratifies thermally in the summer, cau-
sing phosphorus to be released from the sediments. The DAD® aeration-by-destratification system works by curbing the phosphorus, iron and manganese releases originating from the anoxic hypolimnion. The system also prevents the growth of blue-green algae and the production of nuisance chemicals such as ammonia, met-
hane or hydrogen sulphate. The technique is increasingly adopted at the raw water pretreatment stage as a means of optimizing plant operation.