NATURAL & ARTIFICIAL
BY
ASSOC. M. INST. C.E., FELLOW AND MEMBER OF COUNCIL
OF THE SANITARY INSTITUTE, ETC.
AND
H. ALFRED ROECHLING
M. INST. C.E., F.G.S., FELLOW OF THE SANITARY INSTITUTE, ETC.
London
E. & F. N. SPON, Ltd., 125 STRAND
New York
SPON & CHAMBERLAIN, 123 LIBERTY STREET
1902
The Authors, some time ago, read before different Societiesof professional men, Papers[1] dealing with the Natural andArtificial Purification of Sewage, and as these were favourablyreceived, the thought occurred to them that the timemight be opportune for making the information there givenavailable for a wider public.
As, however, a mere republication of the Papers wouldhave been against the rules of the Societies concerned, theAuthors decided to re-write entirely the subject matter, andto bring it up to date, so that the present publication isnot a mere repetition of their old Papers clothed in a newgarb, but an entirely fresh publication, right up to date.
The Authors hope that they have given the informationin such a form as to be readily available for District Councillors,Sanitarians, and all interested in this complicatedsubject.
When considering natural and artificial sewage treatment,it ought to be borne in mind that in the natural treatment wehave to deal with one treatment only, and that, in order tobring the results obtained from artificial processes up to thesame standard, the artificial treatment ought to be supplementedby a treatment for the removal of nitrates fromthe effluent, and another for the removal of pathogenicmicro-organisms, which means one treatment in natural, asagainst three separate treatments in artificial purification.
In addition to this it must be understood that, owing tothe great losses by evaporation and by growing plants, whichare continually at work on sewage farms, especially duringthe summer months, when, as a rule, the flow of water inthe brook that takes the effluent is smallest, the quantity ofthe effluent from the natural treatment is probably only fromone-half to one-third that resulting from the artificial treatment,which is a point of very great importance.
If it can be proved to them that Nature is not sure andtrue enough in its methods, the Authors are prepared toassist it with methods and means produced by the inventivebrain of man. But if such proof is not forthcoming, theyadhere—in preference to groping in the dark—to Nature’sown methods, knowing from experience, that when allowedfull scope and fair treatment, it is most sure in all its ways.That will not prevent them, however, from giving in thefuture, as they have done in the past, the question of sewagetreatment in all its aspec