Land Treatment of Sewage. 



was moBt unsatisfactory ; still later, from the time 

 •when Mr. Kershaw noticed that the land was begin- 

 ning to smell until the close of the experiment, the 

 results were undeniably unsatisfactory. Too much 

 stress must not be laid on the importance of these 

 experimental observations. To be of real use the 

 investigation would need to be modified in a number 

 of ways and extended over a period of some years. 

 But, broadly speaking, the results are of some 

 interest, since they tend to show, as might have 

 been anticipated, that the continuous application of 

 sewage (in the amounts stated) to land of the kind 

 available at South Norwood speedily results in 

 fouling of the land, and in the production of evil 

 odours and objectionable effluents. Nevertheless, 

 considering only the early stages of the experiment, 

 a fair proportion of the second plot effluents was 

 satisfactory. The marked (as a rule) difference 

 between the first and second plot effluents is worth 

 noting, because it tends to show that, given an 

 adequate area of land available for sewage purifica- 

 tion purposes, land even of an unsuitable character 

 can probably effect any reasonable degree of purifica- 

 tion. 



NEW LAND. 



In preparing a new area for 

 Aldershot Camp, sewage the land is chalked, 

 ploughed, harrowed and rolled, all 

 slack places being filled in and the ground thoroughly 

 levelled ; contour grips are cut and the tank effluent 

 let into the contours from the main carrier through 

 sluices. The contour grips in filling gradually 

 overflow in a thin stream over the land until 

 reaching the next grip, when the sewage is cut off 

 and applied to the next succeeding grip, the same 



operation taking place. Plot " A " was brought 

 into operation in May, 1900, and plot " B " in June, 

 1901. " A " was sown with rye grass and sewage 

 applied for about fourteen days, when the land wa« 

 rolled. Sewage was put on again immediately after 

 the rolling. Since then it has been sewaged after 

 the cutting of each crop in much the same way as 

 the old land. Both chemically and bacteriologfically 

 the samples from " A " — viz., (1) May and June, 

 1900, (2) July, 1901, and (3) October, 1901— were all 

 bad. Further samples (4), January, 1902, could be 

 termed high-class effluents chemically, and yielded, 

 from a bacteriological standpoint, on the whole 

 remarkably good results. The data obtained " are 

 of very great interest as showing how long a time 

 was required — from one cause or another — to bring 

 this plot of absolutely sandy soil into a fit state for 

 purifying sewage. This slow ripening of the sandy 

 soil may have been due, among other things, to the 

 great ammoniacal strength of the sewage ; to the 

 dose of sewage having been at first too large ; to the 

 small quantity of lime in the soil ; and to the ground 

 not having been properly consolidated." (Part II., 

 page 20.) " It is difficult to understand why this 

 plot of land should have improved in purifying 

 power to so marked an extent since July 23, 1901. 

 Mr. Kershaw, however, supplies a note to the effect 

 that probably the very heavy rain falling at this 

 period (January, 1902) may have considerably 

 diluted the effluent." (Part III., page 29.) The 

 effluents from " B," while distinctly better than 

 the early effluents from " A," were still not at all 

 good, oxidation not having gone far enough. The 

 superiority may have been due to the better state 

 of consolidation of the ground when the sewage 

 came to be applied. 



63 



