Training Your Personnel: Level 4

Appendix 7.31

Preventing Water Pollution

A comprehensive plan of the water drainage system should be drawn up and where all drains discharge to and all manhole covers should be colour coded. Good knowledge of the drainage system on site and how river pollution can be caused will help prevent water pollution incidents. On the majority of industrial sites there will be two types of drain:

  • Foul water drain: this carries trade effluent- e.g. plant cooling water, to a sewage works for treatment. Authorisation is needed from the local water company prior to most types of effluent being discharged to the foul sewer.
  • Surface water drain: this flows directly to local rivers or streams and carries unsoiled rainwater from roofs, and clean yards.
The majority of water pollution incidents occur when effluent or polluted water enters the surface water drain due to incidences such as where plant cooling water is discharged to this drain and contains chemical additives. Pollution can also occur when spillages of chemicals are allowed to enter the drainage system, or where certain substances are spilt on the ground and over time, contaminate the lower soil layers and then the groundwater beneath- particularly chlorinated solvents.

Consent is required from the Environment Agency before making any discharges of effluent to controlled waters such as streams. Consent is also required from the local water company. This is for most discharges of effluent to the foul sewer.

Key members of personnel should be made aware of the drainage plan. Surface water drains should be coloured blue and foul drains, red- all staff should be aware of the colour coding.



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