Since the banning of sewage sludge disposal at sea in 1998 secondary treatment of sludge is now a vital part of waste water treatment. Initially many water companies opted for incineration, but over the last 10 years other options have been adopted such as producing stabilised sludge and pelletised dried sludge for use as fertiliser for agriculture. Currently over 62% of sludge is used in agriculture and only 19% goes for incineration to produce power. The recent increase in the price of fertilizer is causing an increase in demand for sewage sludge fertilizer. The generation of biogas from sludge is also becoming important due to the recent surge in natural gas prices.

ERG over the last 10 years has supplied a number of odour control systems for sludge dryers, sludge pasteurizers, sludge lime stabilisation plant and more recently biogas conditioning up-steam of engines.

These types of odour control and gas cleaning plants are more complex than other odour control equipment used in the waste water industry. This paper will explain how ERG has dealt with these complexities and review the performance of the equipment.