Discharge into the Sea and the River

DISCHARGE INTO THE SEA AND THE RIVER

Sea

  • This is a way of disposal of sewage from coastal towns. The following points are taken into consideration.
  • The state of the tides, action of discharging rivers and influence of prevailing winds, tending to carry the sewage to the foreshore the possible deleterious effects of the sewage on boating and bathing. The pollution of the beach by the deposit of solids, the possible injury to fishing and the possible infection of shell fish by sewage contaminated with pathogenic organisms such as typhoid bacilli.
  • The sewage is either discharged in its crude state into the sea , or after it has been screened and treated in a settling tank, but unless the position of the outlet and the tidal flow are particularly favourable, further preliminary treatment is usually carried out. In some cases tanks are used to store the sewage during the raising tide and to enable discharge to take place during the ebb tide only. As a method of purifying sewage screening is not very effective, particularly if the sewage has travelled through several kilometers of pipes, because by the time that it has arrived at the screen it is already in a state of emulsion, the solids having become disintegrated but not reduced while passing through the pipes.

Rivers

  • Where the stream is large enough to give a dilution of over 500 volumes the crude sewage may be discharged into the stream.
Last modified: Wednesday, 9 March 2011, 9:53 AM