Siltbuster Supports Kelda Water Services with ASP Refurbishment

10 Jun 2015

When a sewage works is maintained, typically just the process unit concerned has to be taken out of service. However the condition of the existing activated sludge plant (ASP) on a Kelda Water Service site meant that it was necessary to take the whole works off-line during planned maintenance, whilst still maintaining discharge consent compliance.

This posed quite a challenge for Kelda Water Services, which maintains and operates the works supporting over 4,000 personnel.

An entire wastewater treatment plant was needed which was temporary, up to the task, utterly reliable, easy to install and operate, and which would fit on the site while the ASP was offline. Any solution needed to treat 30l/s, – eliminating the need for expensive tankering of the flow off site.

It was with this brief that Paul Thomas, Regional Area Manager for Kelda Water Services, contacted Siltbuster Process Solutions (SPS). He picks up the story:

“We’d used SPS successfully at another activated sludge works, so we knew what they were capable of. We knew SPS had expertise in this area plus a tried and tested fleet of portable, plug and play solutions for such upgrade situations. Their technology and approach were familiar to us – but even so, this project was a big ask.”

Prior to mobilisation on site, the SPS team assessed the system requirements, looking at the population served and the treated water standards to be met. Based on this the SPS team recommended a temporary solution of three duty streams. These comprised of a lamella primary settlement tank, Submerged Aerated Filter unit for biological treatment, plus a lamella humus settlement tank. Both lamella settlement tanks were fitted with auto desludging systems, so that only minimal operator input was required. Hydraulics and minor civils works were undertaken and power requirements considered, to ensure the solution could be brought online rapidly once mobilised to site.

SPS operates a fleet of portable, packaged, compact treatment units, so that solutions can be rapidly deployed onto site. Indeed the entire temporary wastewater treatment plant devised by SPS’ team was mobilised, on site, and operational within 3 weeks of the order being placed. Furthermore, the modular nature of the equipment meant that it was ideal for the constraints of a typical wastewater treatment works, where large areas are not always available, as Paul Thomas explains:

“On projects like this, space is often limited and access can be problematical – so the amount of treatment capacity you can pack into quite a small area is very important.”

While it was being acclimatised, the flow was pumped through the mobile equipment and then back through the permanent plant until consent conditions were met, after which the permanent plant could be bypassed and the refurbishment could begin.

The refurbishment of the activated sludge and final settlement tank system took approximately 12 weeks, during which the temporary treatment works provided the full treatment capacity for the site. Once refurbishment was completed the permanent plant was brought back on line. The flows from the refurbished plant were sent through SPS’ temporary plant until consent conditions were met, at which point the temporary plant could be switched off.

“For a project of this scale and scope, it couldn’t have gone better within the timescales we were working to” concludes Paul Thomas.

The total duration of the project, from mobilisation to the equipment being off site was just 15 weeks. This demonstrates the capability of Siltbuster’s fleet of equipment for this kind of upgrade programme that the industry is embarking on as part of AMP6.