Monitoring Hydrogen Sulphide in Sewer Systems
November 7, 2016
Protecting your assets
Sulphide build up in sewers is a serious issue for water utilities. Aside from the noxious smell associated with the generation of hydrogen sulphide (H2S) which may upset local communities. Lack of control of sulphide can also lead to dangerous levels of hydrogen sulphide gas build up causing a danger to sewer workers and cause corrosion leading to the expensive replacement of the sewer infrastructure.
Sulphur can enter the sewer system in a number of ways. Sulphate is reduced in anaerobic conditions to form hydrogen sulphide and carbon dioxide. The presence of sulphur oxidising organisms oxidise the hydrogen sulphide to sulphuric acid which corrodes the concrete infrastructure of the sewer. Little can be done to prevent sulphur entering the sewers, but action can be taken to prevent it forming hydrogen sulphide which prevents both the formation of the poisonous gas and prevents its oxidation to sulphuric acid.
It primarily enters as sulphate SO 4 2- as a waste product from industry, from sea water ingress and somewhat ironically from the use of aluminium sulphate used in the clarification of raw water in the production of drinking water.