Taking a Brisbane sewage pump station underground

As part of Brisbane City Council’s early works program to relocate public utility services in preparation for Brisbane Metro construction works, Urban Utilities is installing a new underground pump station at Alexander Place Park to replace the existing pump station that services the area to cater for future population growth and development.

Project Manager, Urban Utilities, Peter Nortje, said that unlike the existing pump station, the new one will be a submersible, all-weather pump station that will operate continuously.

“Most of the infrastructure will be underground, including the wet well, grit chamber, emergency storage tank and pumps. The odour control unit, electrical switchboard, telemetry control systems and ventilation pole will be built at ground level,” Mr Nortje said.

By constructing the pump station below ground, the integrity of the green space will be maintained, as there will be minimal aboveground structures, and landscaping will ensure the space remains leafy, open, accessible and welcoming.

As part of the project, new park furniture, a drinking fountain, new turf and additional trees will be installed to enhance the amenity of the park. Its location was also a key consideration, with the site selected at Alexander Place Park ensuring it is in close proximity to the existing sewer network so they can be connected with minimal relocation of existing sewer infrastructure.

Designing the pump station

Mr Nortje said the pump station has been designed to operate in all weather conditions, seven days a week, and will consist of two small 8.5kW lift pumps and three 100kW pumps.

“The five pumps will be underground approximately 15m deep in a well. An associated switchboard with cooling fans will be located at ground level, and a multi-stage odour control unit will be designed to treat the air in the wet well prior to dispersing it to the atmosphere via a 12m high vent stack. “The new SPS will meet the target objectives of the Queensland Environment Protection (Air) Policy (2008).”

Procurement of the equipment was undertaken by Urban Utilities’ delivery partner as part of its contractual responsibility, with the equipment selection based on design and specification requirements.

Mr Nortje said there were five major factors that were taken into account during the equipment selection process, including:

• Anticipated volume of sewage received, allowing for future population growth
• Height differential to get the sewage to the discharge point
• Distance the sewage must be pumped
• Pump reliability, maintenance timeframes and spares availability
• Anticipated wet and dry weather flows Maintenance and repair schedule and costs were all taken into account during the feasibility study, with the pump station designed to minimise the amount of maintenance required.

“The SPS design incorporates innovative techniques that will minimise maintenance. The pumps and wet well may be cleaned twice a year, but the maintenance program will be confirmed once the SPS is fully operational,” Mr Nortje said.

Overcoming challenges during the design and planning stage

The construction of the pump station was not without its challenges, with the location selected requiring careful consideration.

“Traditionally, we select our sites based on the locality, ease of access and the impact on the community, including constructability issues,” Mr Nortje said.

“South Brisbane is a highly urbanised area; we’re working in close proximity to existing high-rise buildings and a railway line. These considerations were taken into account during the design and planning stage.”

Construction underway

The project is now in the delivery stage, with construction activities commencing in April 2020, and is on track to be completed by May 2021, subject to weather and site conditions.

“Urban Utilities has worked closely with the local community and is providing regular construction updates to directly impacted neighbours,” Mr Nortje said.

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