New Zealand's first BEAST Septage Receival Screen simplifies waste management by reducing network damage and maintenance costs while saving costs with seamless installation.

Effective waste management is crucial for cost savings and environmental sustainability. Many municipalities lack adequate screening systems, leading to network damage and high maintenance costs. The Nelson Regional Sewerage Business Unit (NRSBU) saw significant benefits after implementing the BEAST, the first of its kind in New Zealand, at its septage reception facility in Richmond, Tasman.

Innovative Septage Screening

The NRSBU had long struggled with an inadequate system that failed to separate solids of 6mm and above, causing deterioration to their sewerage network. Waste from vacuum trucks, dumped into an empty storage tank, flowed by gravity into a pumping station where it was then pumped to the Bell Island Wastewater Treatment Plant. This process was damaging the network with rough, unscreened materials like stones, debris, and rags contributing to higher maintenance costs and operational disruptions.

The BEAST addressed these issues by allowing tankers to pump septage directly into the screen, eliminating the need for an upstream storage tank. This resulted in significant capital savings, reduced costs, and a simplified process that benefits customers.

The BEAST, with its thick internal castings, can handle ½ bricks, sticks, and stones without damage, unlike other technology in New Zealand with lighter castings, requiring stone traps and macerators to protect them from damage. The BEAST features a dual motor drive, allowing the drum and auger to operate independently at a maximum flow rate of 41 litres per second. Its increased auger speed removes debris quickly, while a slower drum speed enhances capture efficiency. The drum screen, tilted at a 25-degree angle, filters out solids 6mm or larger and eliminates the need for lower drum support arms, preventing rag accumulation and ensuring safety throughout the sewerage network.

The BEAST compacts and dewaters solids to 30% of their original mass before discharging them to a skip, significantly reducing the number of skips sent to landfill over uncompacted solids. The screenings wash function also removes Biochemical Oxygen Demand (BOD) loading from screenings, resulting in minimal odours from discharged screenings.

Seamless Installation Saves Costs

Before selecting the BEAST, alternative options, such as relocating the septage facility to a more spacious site, were considered. However, these alternatives would have involved significantly higher installation costs and longer construction timelines – meaning more disruption to the facilities users and general public.

Instead, the BEAST’s compact footprint allowed for seamless installation within the existing compound, utilising current infrastructure and resulting in lower capital cost than other identified options. The installation process, including connecting the DN250 discharge to the existing gravity wastewater pipe, linking the 3-phase power supply, and setting up the local operator keypad, was completed in just two days.

A Remotely Accessible System

The BEAST operates automatically, eliminating the need for an on-site operator. Adjustments and controls can be managed remotely via a proprietary control panel that sends Supervisory Control and Data Acquisition (SCADA) telemetry signals to a centralised control centre. This allows tankers to discharge their trucks at any time, offering flexibility, reducing wait times, and streamlining the discharge process.

After a successful 90-day trial, the NRSBU purchased the BEAST as a permanent solution. Following this success, two more units have been installed across New Zealand.

NRSBU Operations Manager Brad Nixon says ’Feedback from the users has been positive, with the screen handling even the thickest loads. We’ve also seen a slight reduction in rag and debris conveyed to the treatment plant, and so far, a reduction in odour from the site’.

Features & Benefits of The BEAST

• Engineered for large, heavy debris ladened liquid/solid separation applications requiring fast processing
• Compacts solids to 30% of original mass while reduced BOD loading from screenings minimises odour
• Dual motor drive system - drum and auger driven independently to optimise debris capture and removal
• Special two-stage tank design narrows the inlet and prevents sedimentation
• Drum screen tilted at a 25-degree angle to capture and remove debris faster
• No support arms on influent side of the drum screen eliminates accumulation of rags and wipes

Find out more about The BEAST Septage Receival Screen here.