As monitoring firm Safe Training Systems (STS) says, the production of biogas from wastewater AD ticks all the green eco boxes and has few objectors – it uses waste which would otherwise be destined for landfill or high energy consuming treatment plants. It produces a high energy gas stream, typically 50% methane, and lends itself to gas to grid and CHP solutions.
The problem comes that the waste often contains high levels of contaminants that can quite literally throw a spanner in the works! Predominantly these are H2S and siloxanes, which can be controlled and removed with activated carbon filters, but at a price.
STS claims to have addressed the siloxane management part of this equation with the production of an innovative semi-portable monitor that can be moved around sites owned by a utility to assess the siloxane loading of their filters by analysing the pre- and post-filter gas.
One utility has now used the equipment on four of its wastewater sites and seen the immediate benefit of replacing filters that are shown to be saturated and in other instances postponing planned filter changes where the post filter contamination is still low. Reduction in engine oil changes have been seen with the timely replacement of carbon preventing oil contamination and resultant ongoing damage.
Better management has led to reduced maintenance, reduced replacement parts and longer oil life and a tick in the green credentials box to boot, says STS.
