Operation and management of small sewage works.

  • Great Britain. Ministry of Housing and Local Government
Date:
1965
Catalogue details

Licence: Public Domain Mark

Credit: Operation and management of small sewage works. Source: Wellcome Collection.

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    is used at more than one sampling point contamination of samples may occur. These risks are eliminated if each individual sample is taken directly into a clean small bottle and the composite made up when the sampling is completed. The bottle, of say ten fluid ounces capacity, can be attached by spring clips to a pole and filled by complete immersion in the liquid. The full bottle is removed, corked, labelled and stored under cool but not freezing conditions. At the end of the sampling period the composite can be made up at the works by the sampler, or the bottles can be taken to the council offices for mixing there: whoever mixes the composite then has an opportunity of checking that the individual samples are normal. If any of the samples are unusual the residues can be preserved and sent to the analyst. It has been found worth while to number the bottles permanently, using paint of a different colour for each sampling point. 154. When an authority has a large number of works to manage, or it is difficult to obtain suitable labour, consideration should be given to the use of a transportable, battery-operated, automatic sampler. With such a device sampling is less subject to human error and can be carried out while the works is unattended. 155. Sampling arrangements should always be discussed before- hand with the analyst to ensure that the samples are representative and will provide the information required. 156. At small sewage works, particularly where the sewage is predominantly or entirely domestic, the cost of regular sampling and analysis may be thought to represent an unreasonably high pro- portion of the total operating costs. Nevertheless it is essential that there should be some means of checking the performance of the works as a necessary ingredient of good management. With this in mind the Water Pollution Research Laboratory have devised a simple field test for effluents, which is fully described in the Appendix. The necessary equipment can be purchased either as individual items or as a portable kit, and can be kept at each works or carried round in a car. Some river authorities have adopted this test as a criterion for effluents from very small sewage works. 157. For the field test of the effluent a snap sample is taken, pre- ferably at the same time of day on each occasion, as it is intended for
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