Laboratory assessment of bioproducts for sulphide and methane control in sewer systems.

The effectiveness of three bioproducts (also known as biomaterials) for liquid-phase biological treatment (LPBT) of sewer biofilms to control detrimental build-up of sulphide (H(2)S) and methane (CH(4)) in sewers was tested in a laboratory system mimicking a rising/force main sewer pipe. Bioproduct A claims to disrupt cell-to-cell communication of sewer anaerobic biofilms while Bioproducts B and C claim to enhance sulphidotrophic (sulphide-oxidising) capacity of the sewer biofilm, to avoid sulphide accumulation. The results demonstrated that all three bioproducts tested had no or negligible impact on sulphide or methane control, as opposed to traditional sulphide-controlling chemicals widely used by the wastewater industry such as oxygen, nitrate, iron salts and magnesium hydroxide. Those had previously been demonstrated to be effective using the same laboratory system with the same testing protocol. The implications of the findings are discussed. It is concluded that field application/trials of these three bioproducts are not warranted. It is recommended that other bioproducts should be subject to similar rigorous tests prior to being taken up by the water industry for field trials/application.