1 10 REPORT 1875. 



the absence of any better mode of getting rid of it, and in consequence of the 

 loss whicli results from attempting to deal with it as a manure, it has even 

 been proposed to destroy it by burning. 



The Committee inspected the works at Ealing in September 1871. On 

 that occasion it was found that General Scott's process was not in operation, 

 although he was treating the sewage experimentally with deodorizers. It 

 was decided therefore to test the existing system of treating sewage by up- 

 ward filtration ; and for this purpose it was arranged that General Scott 

 should not apply deodorizers to the sewage during the sampling &c. by 

 the Committee. It appeared, however, that the Local Board kept a man at 

 the upper end of the town mixing deodorizers with the sewage every day 

 (except Sunday). The deodorizing-mixture was being added to the sewage 

 at the rate of 20 gallons an hour, but its composition was not stated. 

 Samples were taken on behalf of the Committee : — 1st, of the sewage as it 

 entered the works ; 2nd, of the sewage after leaving the precipitating-tank ; 

 3rd, after passing through tlie first filter ; 4th, after passing through the 

 second filter. The samples were taken six times during the day, the quan- 

 tity taken being proportioned to the flow at the time. It was further deemed 

 advisable to ascertain the effect of the deodorizing-mixture added by the 

 Local Board; and for this purpose arrangements were made that nothing 

 should be added on a certain day, when samples of the sewage and of the 

 effluent water at the outfall were obtained. The analyses of the six samples 

 will be found below; and it will be seen that the results confirm the investi- 

 gations of the Eivers Pollution Commissioners, and that the process does not 

 render the sewage fit to be discharged into running streams. 



The next investigation by the Committee took place in March 1872, when 

 the sewage works were wholly under General Scott's control. On this occa- 

 sion gaugings were taken which confirmed the previous statements of the 

 daily discharge of sewage being about 400,000 gallons. The samples were 

 taken every two hours, in the proportion of jyVu ^^ ^^^ ^^^^ ^^ ^°'"'* '-^'^^ 

 gaugings and samplings extended over five days, and the analyses made for 

 the Committee by Dr. llussell are given below. 



A further inspection of the Avorks was made last month (July) during 

 very hot weather, when it was found that the process was proceeding with- 

 out any nuisance whatever, although the depositing-tanks are clearly not of 

 sufficient capacity, a defect which it is intended to remedy. The effluent 

 water, after leaving the depositing-tanks, contains some suspended matter, 

 and has a scum on its surface which can only be got rid of by filtration. It 

 is proposed to filter it with this view; but the liquid will still contain the 

 soluble organic impurities (see remarks on analyses), which can only be re- 

 duced in quantity by filtration through soil by means of irrigation, for which 

 the effluent water of Ealing is well adapted. 



The open ditch, before referred to, which conveys the deodorized sewage 

 from tbe outfall to the Thames, was carefully examined on this occasion, but 

 not the slightest smeU was detected ; the water has, however, a yellow tinge, 

 from a slight precipitate which it deposits along the line of the ditch. This 

 15 no doubt due to the insufficient capacity of the depositing-tanks, the 

 increase of which will probably effect an improvement. 



One of the difficulties attending the process as now conducted, is the dry- 

 ing of the precipitated sludge with sufficient rapidity. If this is done by 

 heat, it is liable to cause a nuisance, being by far too slow in action even at 

 Eahng, with only about 2 tons of sludge daily. It is proposed in this case to 

 force the water out of the sludge by means of Needham and Kite's hydraulic 



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