Compact primary settling tanks for Hong Kong cavern project

An innovative project in Hong Kong will relocate the ageing Sha Tin sewage treatment works into caverns nearby. Several issues with the existing site will be resolved including the availability of 28 hectares of land that can be repurposed for beneficial uses.

The project has required considerable planning and Nordic Water, a Sulzer brand, has been supporting the design of the primary settling tanks. The new equipment will need to be compact, efficient and reliable.

“Sulzer and Nordic Water are excited to be involved in a project that will be of great benefit to the local population in Hong Kong.”

Christian Eklund, Segment Development Manager, Asia, Nordic Water

The challenge
The main challenge is building a whole new sewage treatment works with the same capacity as the old site, which occupied 28 hectares, all housed in a cavern. Restricted space of just 14 hectares and limited air movement pose several challenges in terms of physical size and odor control.

Sulzer has supported the design process with innovative products that have proven successful in similar projects in Singapore and Scandinavia.

The solution
Sulzer will supply a modular solution based on the Lamella LPS plate packs as well as bottom and surface sludge scrapers. This high-efficiency design will optimize space and ensure the primary settling tanks deliver the required capacity from a compact footprint and serve the local population of 700’000.

This robust and efficient solution will be installed in a parallel arrangement that will enable operational redundancy and enable maintenance without affecting the treatment process

Customer benefit
The Lamella LPS plate packs are proven to provide high rates of solids removal, which reduces the workload on equipment downstream. The reduced footprint optimizes the limited space in the cavern, ensuring all the equipment can deliver the required capacity.

Coupled with the effective and efficient sludge scraper systems, Sulzer’s solution will enable the new sewage treatment works to function perfectly within the cavern. When complete the project will enable 28 hectares of land to be repurposed.