Sewage treatment upgrade withstands nature’s fury



An upgrade of a council sewage treatment plant in Australia certainly proved timely for the local body.

An upgrade of a council sewage treatment plant in Australia certainly proved timely for the local body.

An upgrade of a council sewage treatment plant in Australia certainly proved timely for the local body.

The Richmond Valley Council upgrade of its Casino Sewage Treatment plant has paid immediate dividends by withstanding the fury of June’s storms and flooding without suffering any polluting spills or odours.

The turnkey upgrade – which included retrofitting of fine screening technology by CST Wastewater solutions – was completed just days before the bad weather along Australia’s East Coast dumped more than 160mm of water on the council region within 48 hours.

The Council couldn’t have timed the upgrade any better. Their foresight and technology upgrade was perfect,” says CST Wastewater Solutions managing director Michael Bambridge. “The Northern Rivers District of NSW is one of the most flood-prone areas outside of the tropics, where events like this are likely to occur and reoccur, so the investment in new technologies has already paid off.”

The retrofit project – of a type that is applicable to councils and industrial uses throughout Australia and New Zealand – replaces the previous coarse raked screen design with current fine screening technology. This captures more solids to reduce potential blockages in tanks and downstream equipment, while reducing odours by sealing the inlet works and by the installation of new odour control units.

The project’s high-efficiency fine screening SFC technology (screen press for channel installation) is engineered to deliver low-maintenance performance with reduced WHS hazards for municipal and industrial waste water operators.

The SFC allows for a much finer level of screening – 5mm compared with typical old systems at 60mm or more – which has led to a significant reduction in solids in the tanks, while producing more efficient treatment with less maintenance

The retrofit also involved the installation of an SDS 20 compactor with two inlets – one for each screen – to dewater screenings to 25-30% dry solids. Each screen has an enhanced design capacity of 250L/s flow, providing a total capacity of 500L/s.

Technology transplant

The original inlet works at Casino STP were designed with a coarse manual raked bar screen system. The functional components of the treatment process downstream of the bar screen receive a high amount of debris, which formerly impacted the efficiency of the treatment process. The original inlet area also received a high amount of odorous gases, which previously contributed significantly to odours emanating from the treatment plant.

In addition to minimising these issues, the upgrade project involved fitting new technology into an existing layout, including tailoring the screens to fit into the existing formed channel.

The SFC technology involved in the retrofit – designed to lower investment, operational and maintenance costs in screening of municipal and industrial waste water with compacting of extracted solids – has also cut the amount of maintenance and waste that has to be handled by plant operators, reducing operational health hazards and improving OHS performance.

The same benefits are widely applicable to other industry and municipal applications, says Mr Bambridge.

The technology is also suitable for applications such as food and beverage, manufacturing and processing, mining, energy and resources camps where its low maintenance/high hygiene qualities are appreciated, agribusiness, and remote installations where low maintenance and high efficiency is a priority for users who don’t need to have specialist staff constantly available.

Not only are the tanks clearer and more efficient now, but the screen extractor also operates on level control and is fully automated, eliminating the previous labour-intensive operator handling of screenings,” he says.

The robust and proven extractor is constructed from AISI 304 or 316 stainless steel without the need for hanger, intermediate or bottom bearings. Featuring a space-efficient design suited to small sewage plants, the standard unit can handle up to 1000m3 an hour with custom engineering also available for particular installations. A vertical version is also available to easily retrofit into existing pump stations with depths up to eight metres, the screen allows removal of material before pumping, says Mr Bambridge.

The versatile SFC screen extractor can be installed in a channel or supplied with self-supporting tank, complete with inlet and outlet flange and optional bypass screen.

CST Wastewater Technology packages

New engineer-and-build water and waste water treatment and recycling packages from CST Wastewater Solutions are aimed at industries and municipalities that want to lower the cost and complexity of such projects.

The design, supply and install packages – incorporating global and locally manufactured technologies proven in use by some of Australia and New Zealand’s leading companies and councils – are aimed particularly at:

Councils seeking engineering assistance to develop clear choices and optimum solutions incorporating advanced low-maintenance technologies providing high levels of water purity while reducing maintenance, waste handling and OH&S issues associated with running them.

Industries seeking readily constructed or portable, low maintenance solutions for operations particularly in remote, ecologically or environmentally sensitive areas – ranging from resources or agribusiness developments in the country or outback, through to food, beverage, manufacturing and processing plants sharing precious water resources with urban areas.

Rather than presenting such organisations with a jigsaw of disparate collections of technologies and engineering services options for them to piece together, the packaged solutions focus on clear, properly engineered solutions that deliver what they promise. CST offers turnkey solutions based on a known raw water quality and guaranteeing water quality outcomes thus giving user engineers significant confidence in the outcomes and limiting their exposure and potential concerns, says Michael Bambridge.

CST Wastewater Solutions has been involved in projects, technologies and services that increase environmental sustainability since its inception over 25 years ago. CST represents Global Water Engineering (GWE) technologies in Australia that are at the forefront of waste-to-energy initiatives, cleverly turning a problem, wastewater, into a profit, biogas, which can be used to power boilers, reduce fossil fuel use and converted to electricity.