What's 14 football fields long and capable of capturing 65,000m3 biogas per day? It's a new lagoon cover in Australia, custom-designed by GTI.
Geomembrane Technologies Inc. (GTI) is pleased to join forces with John Holland/KBR Joint Venture to construct and install a new lagoon cover for Melbourne Water’s Western Treatment Plant (WTP) in Werribee, Victoria, Australia. The 7.6-hectare (19-acre) cover replaces a previous cover and is designed to capture biogas, control odor and minimize greenhouse gas emissions from one of the site’s primary treatment lagoons.
Melbourne Water’s WTP is a “world leader in technical and environmental innovation,” and is ranked among the top performing Australian and international water utilities. Besides treating the wastewater from up to half of Melbourne’s population, the site contains world-renowned Ramsar wetland, home to thousands of migrating birds.
Most of the biogas captured by the new cover will be converted to electricity. In conjunction with the other anaerobic cover at WTP, captured biogas generates up to 95 percent of the site’s annual electricity needs. GTI will design, install and commission the cover in phases to progressively capture biogas and manage odor.
GTI is no stranger to Melbourne Water and WTP. GTI supplied two covers and a biogas handling system in 1998, which established biogas recovery from the primary anaerobic lagoons. Since then, GTI has been involved in various upgrade and maintenance projects at WTP.
The new cover has several interesting features to address the conditions of the anaerobic lagoon. For example, the cover is divided into two parts because the wastewater is not screened and tons of debris collects in the first part of the lagoon and is held under the cover. The first part of the cover is composed of several segments designed to be removed for sludge and debris excavation while the remainder of the cover remains in operation. The cover will also have accessories such as access hatches and inspection ports to allow for maintenance and operations.
The design work has already begun, and the construction work will extend through 2016. Once completed, the cover will be larger than 14 football fields and collect up to 65,000m3 of biogas per day.