Pilot testing of manganese oxidation in a high‐rate sedimentation process for the reprovisioning of the Sha Tin water treatment works, Hong Kong Special Administrative Region

Abstract

AbstractThe Sha Tin water treatment works (STWTW), Hong Kong Special Adminstrative Region, was commissioned in 1964 with an initial treatment capacity of 364 million litres per day (MLD). Since then it has undergone three stages of expansion to reach the current nominal capacity of 1227 MLD. The plant is in need of an in situ reprovisioning. The challenge is to complete the reprovisioning while maintaining a minimum output of 900 MLD, with any shutdown to be limited to 8 h generally. With the site already fully utilised, the key to success is to first replace the conventional low‐rate sedimentation process with high‐rate robust processes to free up the much needed space. Among other requirements, the chosen process must also be capable of treating water with variable turbidity and removing spikes of manganese effectively. The project team conducted a 4‐month pilot testing programme with an Actiflo® high‐rate pilot plant and the key results are described.