End to sewage smell likely

Press, 20 December 1984, Page 5

End to sewage smell likely

A biofilter process may be the solution for the offensive smell produced at Christchurch’s sewage-treat-ment works. The Christchurch Drainage Board’s chief engineer, Mr H. P. Hunt, has just returned from a four-week study of odour control measures at sewage-treat-ment plants in the United States and Europe. He told the board last evening that from what he had seen he was confident that there were several ways a biofilter could overcome the smell produced by the Bromley works’ trickling filter. He said he believed that a fibrous peat would be the

best material for the filter, but if this could not be obtained within a reasonable distance of Christchurch, soil mixed with an organic material such as dried sludge or compost could be used. Although peat and compost filters did themselves produce an “earthy” smell Mr Hunt said that this quickly dispersed. Mr Hunt said he was impressed by the number of sewage-treatment works that had overcome the strenuous complaints from residents by using this sort of odour control measure. Answering a question by Mr M. R. Carter, Mr Hunt

said that a wet oxidation plant could not be completely ruled out, but it would cost more and he believed that a peat or soil filter could do the job satisfactorily at a much lower cost. It had been made clear to him that pilot studies for using local materials should be made first and he said that the board must now investigate available peat sources and try to find a substitute for the heather often mixed with the peat to give it a better substance. If suitable peat was not economically available experiments should be done with soil mixtures.