The experimental bacterial treatment of London sewage : being an account of the experiments carried out by the London County Council between the years 1892 and 1903 / by Frank Clowes and A.C. Houston.

  • London County Council
Date:
1904]
Catalogue details

Licence: In copyright

Credit: The experimental bacterial treatment of London sewage : being an account of the experiments carried out by the London County Council between the years 1892 and 1903 / by Frank Clowes and A.C. Houston. Source: Wellcome Collection.

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    oxidised product. Both are produced by the oxidation of nitrogenous compounds present in the sewage. Their presence and permanence indicate that purification of the sewage has taken place, since they cannot exist in raw sewage. It lias been shown that the presence of nitrate in an effluent may prevent the putrefaction of a certain amount of organic substances from occurring in another effluent with which the nitrate effluent has been mixed. XIV. Alteration oe method of treatment suggested by the EXPERIMENTS. The present method of dealing with the London sewage is by treat- ment with solutions of lime and of protosulphate of iron, followed by sedimentation in settling channels. The effluent from this process is allowed to flow into the river Thames and the sediment or sludge is carried out and discharged on a falling tide in the estuary of the river. The introduction of this method of treatment was the means of consider- ably improving the condition of the water of the river Thames below London, but at that time it was stated that the sewage effluent would still carry into the river a large amount of putrescible matter in solution, and it was recommended that, as opportunity occurred, the effluent should be further treated on land or by other means, before it entered the river. As no suitable land was available at the Council’s Outfall Works, land treatment was not seriously considered, but on the publication of the Massachusetts experiments on the bacterial purification of sewage in coke-beds, a series of experiments was started by the London County Council with a view to obtaining information as to the suitability of the process to the treatment of London sewage. At first the experiments at the Council’s Outfall Works were con- cerned only with the treatment of the effluent from the “ chemical sedimentation ” process. The results obtained were so satisfactory as to warrant an extension of the experiments in the direction of the treat- ment of crude sewage. The result of the later experiments with crude sewage has been such as to show that the sewage of London can be satisfactorily treated on the following lines. ]. The crude sewage as it arrives at the Outfall W orks, and after it has been deprived by “ screening ” of the coarser matters only, would be allowed to flow through a catch pit or detritus chamber in which a lawe proportion of solid suspended mineral matter would be deposited. The rate of flow through the detritus chamber would be regulated in such a manner as to allow of the deposition of a maximum quantity of the heavier mineral matter, such as road detritus, with a minimum quantity of the putrescible matter. With a suitable rate of flow, the deposited matter in the detritus chamber should consist almost entiieh of road detritus, which could be deposited on waste land without becoming offensive or injurious. 2. After passing through the detritus chamber, the sewage would pass through the present settling channels, at such a rate that it would