E. & F. N. SPON, Ltd., 125 STRAND
New York
SPON & CHAMBERLAIN, 123 LIBERTY STREET
1902
PREFACE.
The Authors, some time ago, read before different Societies of professional men, Papers[1] dealing with the Natural and Artificial Purification of Sewage, and as these were favourably received, the thought occurred to them that the time might be opportune for making the information there given available for a wider public.
As, however, a mere republication of the Papers would have been against the rules of the Societies concerned, the Authors decided to re-write entirely the subject matter, and to bring it up to date, so that the present publication is not a mere repetition of their old Papers clothed in a new garb, but an entirely fresh publication, right up to date.
The Authors hope that they have given the information in such a form as to be readily available for District Councillors, Sanitarians, and all interested in this complicated subject.
When considering natural and artificial sewage treatment, it ought to be borne in mind that in the natural treatment we
have to deal with one treatment only, and that, in order to bring the results obtained from artificial processes up to the same standard, the artificial treatment ought to be supplemented by a treatment for the removal of nitrates from the effluent, and another for the removal of pathogenic micro-organisms, which means one treatment in natural, as against three separate treatments in artificial purification.