Odour is usually caused by the presence of hydrogen sulphide, mercaptans (Organic sulphur components) and ammonia, but also multiple other VOC’s (volatile organic compounds) bringing numerous odour complaints at e.g. WWTP’s, pumping stations and composting plants. An odour control system therefore will have to treat not only hydrogen sulphide, but also other pollutants to reduce the total odour.Compost-based biofilters yield too many problems with acidification, dehydration and media decomposition. Biofilters with lava rock, so called biotricklingfilters, have a long packing lifetime (at least 10 years). As a result, the operational stability appears to be better and they are preferred because of their smaller size and robustness. But also these systems not always comply to the emission demands,clog frequently and can have considerable running costs.
In biological processes every micro-organism prefers it’s own process conditions; especially pH, temperature and substrate are playing important roles. Usually a variety of pollutants is present in the exhaust air, so placement of only one biological filter often appears not to be sufficient. For that reason a combination of processes is necessary.
DMT developed a multiple stage biological odour control process called Odourex®. This process, using highly structured media instead of lavarock, is excellent for reaching high removal efficiencies on various polluting components removing all odour components on a very small footprint with low operating costs.