§ Mr. Crouchasked the Secretary of State for the Environment (1) what engineering studies he has made into the question of eliminating the objectionable smell which is produced by the Porteous Process for the treatment of sludge at sewage disposal works;
(2) if he is satisfied that the Porteous Process for the treatment of sludge at sewage disposal works is efficient in all respects; whether he is prepared to recommend it to all local authorities; and what advice he gives regarding its suitability in all geographical situations in view of the noxious smell produced;
(3) what estimate he has made of the advantages of the Porteous Process for the treatment of sludge at sewage disposal works compared with other systems.
§ Mr. Michael HeseltineHeat treatment processes for sludge, such as the Porteous Process, are used to facilitate mechanical dewatering. The combination has the advantage over the more traditional sludge drying beds that it requires less land and less labour for unpleasant work, and is both faster and independent of the weather.
I am not satisfied that any particular sludge treatment process is satisfactory in all circumstances and my advice to a local authority considering a process with which it is not fully familiar would generally be that it should if possible see it in use elsewhere before coming to a decision.
The problem of smell is particularly acute at the Canterbury sewage disposal works and the Department's engineers have been associated with the council, 451W their advisers and the manufacturers in their attempts to reduce or eliminate it. The Department has not, however, undertaken engineering studies of the Porteous Process in this connection: these are the responsibility of the manufacturers.
§ Mr. Crouchasked the Secretary of State for the Environment how many sewage disposal works in Great Britain employ the Porteous Process for the treatment of sludge.
§ Mr. Michael HeseltineI regret that this information is not available but I believe that the number is fewer than 20.