Post-Cyclone Restoration of a Lamella Pre-Treatment System
Gisborne, New Zealand
Client
Gisborne District Council
Plant Capacity
24 MLD
Technology
Clarification, Sludge Removal
Water Source
River Water, Dam Water
Quality Issue
Elevated suspended material in raw water
Customer Need
Restoring the Pre-Treatment System to Pre-Cyclone Capacity
Following the devastating impact of cyclone Gabrielle, the Gisborne District Council faced a critical challenge: restoring water treatment capacity to pre-cyclone levels. Before the cyclone, the plant met city demand effectively. However, post-cyclone, the ability to treat water significantly diminished, severely affecting the cityโs water supply capacity.
The impact of Gabrielle on two of the cityโs main water supply dams exacerbated the situation, with high levels of silt from slips within the dam catchment rendering water treatment inadequate to meet normal city demand. The urgent installation of a lamella pre-treatment system was needed to address these challenges.
What We Did
Identified a Pre-Treatment Solution for Reinstatement
To address the challenges posed by cyclone Gabrielleโs impact and mitigate ongoing risks from slips in the dam catchments, a replacement of the prefiltration system was identified as the optimal solution, including the installation of a new lamella pre-treatment system.
This approach aimed to reinstate treatment capacity to pre-Gabrielle levels and adhere to strict timelines, ensuring a critical lifeline through the summer months when water demand peaks.
Designed and Built a New Lamella Pre-Treatment System
FILTEC swiftly addressed the Gisborne District Councilโs urgent need, embarking on a comprehensive project to design, construct, and retrofit the new pre-treatment technology within the existing settling basin of the Waingake plant. The project featured a 24MLD Parkson lamella pre-treatment system, offering a reliable solution for maintaining water quality standards.
The strategically inclined lamella plates facilitated improved settling of suspended solids, ensuring a higher standard of water quality. This innovative solution significantly improved treatment effectiveness, ensuring the reinstatement of critical water supply levels to pre-Gabrielle standards.
Integrated a Sludge Removal System
In conjunction, FILTEC integrated the SedVac sludge removal system. This system, complementing the lamella pre-treatment, ensured the removal of accumulated sludge without disrupting the treatment process. By preventing the buildup of sludge, which can hinder the treatment process by occupying space in settling basins or clogging filters, the SedVac system significantly increases the reliability and treatment capacity of the entire plant.
Throughout the project lifecycle, FILTEC maintained a steadfast focus on the Gisborne District Councilโs priorities and expectations. With a commitment to reliability and efficiency, the team executed thorough planning, ensuring that every aspect of the project met the specific needs of the community.
The Result
Reliable Drinking Water for Gisborne Community
The completion of the Waingake pre-treatment plant, featuring the lamella pre-treatment and sludge removal system, signifies a significant milestone in Gisborneโs water management efforts. The restored facility ensures the community receives a continuous supply of safe and dependable drinking water.
FILTEC recognised the essential role of water security in the community and worked collaboratively with the Gisborne District Council to deliver a resilient and sustainable solution. The success of the project reflects FILTECโs commitment to being a reliable and supportive partner during challenging times.
