ENVIRONMENTALLY SUSTAINABLE ODOUR CONTROL FOR THE MERRIMAC WWTP UPGRADE

摘要

A $55 million upgrade of the Merrimac Wastewater Treatment Plant has been completed by the Merrimac WWTP Waterfuture Alliance to cater for the substantial growth predicted for the Gold Coast population. This upgrade involved increasing the treatment capacity by around 60 percent to 57.5 ML/d. Implicit in this upgrade was the effective management of odour emissions from the new facility. It comprises the covering of the main bioreactors and other selected equipment, the installation of ductwork for extraction of foul air from these tanks, an expanded inlet works and biosolids processing facilities and finally a new 52,000 m~3/hr odour control facility. The selection of areas to be controlled for odour was based on extensive emissions sampling of existing facilities and associated dispersion modelling. Modelling was used to gauge the cost effectiveness of the various odour control scenarios in eliminating nuisance odours to the surrounding community. The odour control facility selected for such a large plant was unique in that it represented an environmentally sustainable approach to odour control. This was achieved through the use of bacteria for the primary treatment stage rather than hazardous chemicals, as has been the case for most other large wastewater treatment plants around Australia. The facility consists of four bioscrubbers followed by four activated carbon filters and is currently the largest biological odour control facility for a wastewater treatment plant in Australia. This paper discusses the integrated design approach to the odour management works and the construction, operation and performance testing of the facility, which has successfully achieved the project objectives on time and under budget for the benefit of Gold Coast Water and the community. It also details the design philosophy of the project that featured not only environmental, but practical sustainability of this essential community asset.