Used as stand-alone packages, or with Dry Media polishing filters, ERG’s bio-scrubbers provide trouble-free odour control for highly contaminated, small gas flows (<3,000m3/hr) emanating from waste water treatment processes.

ERG’s bio-scrubbers are filled with durable, bio-inert pumice media, and are specifically designed to provide outstanding value for money and simple operation. Our bio-scrubbers need only a filtered final effluent supply and a drain connection – there is no requirement to dose chemicals into the bio-scrubber, and so the SHE (Safety, Health and Environmental) issues associated with their delivery and storage on site is removed.

A specially selected cocktail of bacteria, enzymes and nutrients are pre-seeded in the bio-scrubber to ensure rapid development of the odour neutralising bacteria which colonise the pumice bio-media. The bacteria digest the odour-causing compounds, which typically include H2S, mercaptans, organic sulphides and ammonia. The optimised environment for bacterial activity is maintained by controlled irrigation with filtered final effluent, or water dosed with low level nutrients if no final effluent is available.

Designed and built to BS4994 and fully compliant with WIMES 8.05, ERG’s bio-scrubber systems offer assured performance and competitive costing.

All our systems are custom-designed for the odour control duty required, and include a vessel and irrigation system, biomedia, air extraction fan and ductwork, and electrical control panel.

The key advantages of ERG bio-scrubbers are:

  • The inert bio-media, pumice lasts for 10 to 20 years instead of just 3 to 5 years in the case of alternative bioscrubber media and wood chip used in biofilters.
  • The pumice does not decay or suffer from acidification or compaction ensuring contamination removal remains constant for the life of the filter.
  • The units are highly compact with a small footprint when compared to woodchip biofilters – they typically use bed depth up to 4m and residence times of 25 seconds as compared to bed depths of 2m and residence times of more than 40 seconds for wood chip biofilters.
  • They are able to reliably treat high levels of contamination (over 100ppm H2S).
  • The bio-scrubbers achieve removal efficiencies of >98% H2S removal and >95% odour removal in a single tower.
  • The operating costs are low when compared with other odour removal technologies.
  • The absorption of the contamination (mainly H2S and sulphurous compounds) into the bio-film around the pumice, and subsequent biological aerobic degradation, forms sulphuric acid effluent which is stable and will not convert back to H2S when it is released to drain. The bio-scrubber is optimised to ensure an acceptable pH in the effluent stream.


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