A $35 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.
Implicit in this upgrade was the effective management of odour emissions from the new facility comprising covering of the main bioreactors and other selected equipment, and the installation of ductwork for extraction of foul air from these tanks, an expanded inlet works and biosolids processing facilities to a new 52,000 m³/hr odour control facility. Selection of areas to be controlled for odour was based on extensive emissions sampling of existing facilities and associated dispersion modeling.
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 one of the largest biological odour control facilities 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.