140 TOWN SEWAGE, AND ITS 



natural agents, they extract and preserve the dissolved and 

 suspended impurities of sewage, by what is called the A. B. C. 

 process, and it is sold as a dry portable manure at £3, 10s. per 

 ton. There was a large show of farm and garden produce grown 

 by this manure in October 1882 at Aylesbury, and finer samples 

 of corn, turnips, potatoes, onions, &c., could scarcely be got 

 too'ether. The value of the manure was thus demonstrated to 

 the manv visitors of all classes who attended the exhibition. 

 This system of sewage treatment has been in operation for 

 seven years, with pretty satisfactory results. Votes of satisfac- 

 tion have been annually passed by the Aylesbury Sanitary 

 Authorities. The process is attended with no nuisance, and the 

 effluent water may be passed into any brook or river. 



Aylesbury has a population of 8000, and the daily quantity 

 of sewage is about 250,000 gallons in dry weather, but much 

 more in wet seasons. The name of the A. B. C. process is 

 derived from the initial letters of the principal constituents of 

 the precipitants — namely, alum, blood, clay, and cbarcoal. The 

 clay and charcoal, and where necessary a little lime, are finely 

 ground up with water to form an emulsion, and mixed with the 

 sewage ; a solution of alum is then added. It will best illustrate 

 the process to give the plan of the tanks and the explanation. 



The sewage of the town flows to the works by gravitation, and 

 is discharged from the sewer at the point marked A, where 

 there is a grating to arrest rags, &c. It receives here from the 

 trough marked B the proper proportion of the purifying mixture, 

 which at once removes all offensive smell, and after flowing a 

 few feet the precipitating agent is added from the trough marked 

 C. 



The sewage now having received all the materials necessary 

 for purification flows along the cliannel D to tank Xo. I. entering 

 at the point marked E, and thence through the taniv passing 

 round the partition board marked F, through the outlet G, into 

 the channel H, where it may be compared with the sewage flow- 

 ing into the tank, and it will be observed that most of th3 solid 

 impurities have been deposited. The water now passes into the 

 tank Xo. II. at inlet marked I, round partition board marked K, 

 through outlet L, into channel marked M, where it will be seen 

 that it has become still clearer and brighter. It now flows 

 through the inlets marked X into tank Xo. III., and pass'ng 

 slowly through is discharged at outlet marked 0, into the 

 channel P, thence flowing round the partition board Q, into 

 channel E, to the outfall S, where it is finally discharged in a 

 purified condition, within the requirements of the Elvers 

 Pollution Act, and fit to flow into any river. 



It should be further explained, that when sufficient sludge has 

 been collected in the first tank, the treated sewage is shut off 



