Water Quality Improvements for Household Usage
The Dovedale water supply scheme was originally set up as stock supply. Over time the scheme had expanded to include supply to the Upper Moutere area with increased household usage. Water supply volume and quality were ongoing issues with an old surface take from a small creek.
The Tasman District Council required a solution that provided water quality improvements for household usage. The solution needed to make use of the existing water source while improving the quality of water delivered.
Although the quality of the water from the plant was significantly improved, it was still a requirement for it to be filtered and UV treated at each individual household for potable use.
What We Did
After studying the theoretical behaviour of the solid particles, FILTEC proposed the design and installation of a tube settler lamella clarifier plus a self-cleaning filter. This method was the best solution to maximize turbidity removal without using chemicals.
The FILTEC tube settler clarifier allows the removal of 80-90% of sediments from the raw water source while minimising the total plant footprint. Raw water from the water source flows by gravity through to the FILTEC tube settler clarifier to a 5m³ balance tank.
Raw water pumps then pump the water through an in-line strainer with a 3.1mm orifice heavy duty sieve to retain larger particles. A self-cleaning filter then removes the finer particles before being chlorinated and diverted to the treated water tanks.
Sludge gathered beneath the lamella tube settler is discharged into sludge drying beds via a sludge discharge pump. This allows the solids to be safely collected and disposed of off-site.
The water treatment upgrade achieved a better degree of turbidity and particle removal in comparison with the existing plant, making the water safer. The system achieved significant water quality improvements for household usage. Although customers still need to treat their individual household water with cartridge filters and UV disinfection in accordance with the Building Code prior to use.
water quality improvements for household usage