POLYACRYLAMIDES IN DRINKING WATER TREATMENT AND RECYCLING OF SLUDGE
Report No FR0119
To review the usage of polyacrylamide polyelectrolytes in the treatment of drinking water, including the treatment of waterworks sludge.
The Fifteenth Statement (March 1989) of the Committee on Chemicals and Materials of Construction for Use in Public Water Supply and Swimming Pools set a reduction in the maximum permitted content of free acrylamide monomer in polyacrylamide or acrylamide-acrylate copolymers and a reduction in the average dosage of the polymers. This regulation applies to the use of these polymers directly on the water being treated for supply. It was known that polymers of the same kind are also used in waterworks sludge treatment and that in some cases the water recovered from sludge treatment are returned to the main treatment processes. In such cases the concentration of acrylamide in the drinking water would be increased. The Committee had little information on polymer usage in sludge treatment and WRc were asked for such information.
V RESUME OF CONTENTS
The usage of polyacrylamide polyelectrolytes in drinking water treatment and waterworks sludge treatment is examined with particular consideration to the recycling of sludge liquors. Typical polymer dosages in water and sludge treatment are identified from results of an informal survey of a chance sample of 15 water treatment works. It is shown that the amount of polymer used in waterworks sludge treatment is significant compared with its use directly in water treatment.
The scope for the reduction in polymer usage and further reduction in monomer content is discussed. A list of possible methods for reducing polymer usage is given. The conclusions and recommendations reflect the subject of polymer usage and monomer content justifies further attention.
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