MOTORS, DRIVES AND ENGINES
PUMP AND WATER TREATMENT UPGRADES BRING FORBES WATER TREATMENT PLANT BACK TO LIFE By Lauren DeLorenzo, Journalist, Pump Industry magazine
When a water treatment plant is decades older than the local government area that it services, it is bound to experience some aches and pains that result in a lower drinking water quality. This was the case for Forbes Shire Council’s water treatment plant, with equipment reaching the end of useful life or not working as efficiently, and continual breakdowns requiring maintenance. To rectify these issues and ensure the plant can continue to produce high-quality drinking water for decades to come, Council undertook an upgrade to Plant A and Plant B.
T
he Forbes Water Filtration Plant, which is situated on the Lachlan River, is a conventional filtration plant comprising two trains (Plant A and Plant B) which have their own mixing tank, flocculation and clarifier tanks. Combined, the plants have the ability to deliver 26.5ML per day. Upgrades of Plant A and Plant B began in 2019 to bring them in line with the highest modern efficiency and monitoring standards required to meet the needs of the community and NSW Health legislation. Forbes Shire Council Project Officer (Water), Andrew Quirk, said that the upgrades needed to be made for the continued operation of the water treatment plant. “All these upgrades and replacements were needed as our plant had all but reached its useful life age with multiple issues starting to arise – the main issue being the filters not performing consistently,” Mr Quirk said. “With Plant B first constructed in 1946, and Plant A built in the 1960s, we were experiencing continual breakdowns, which led to us not always meeting drinking water health guidelines.” Other initial issues in Plant A included the failure of a filter. The filter had an old underdrain system, where the pipe had rusted through and filter media was lost through the filter, moving through to the cellar tank. As the filter had been coated in a black epoxy, there was no visual reference for when it would be back in service. The filter had been out of service for a number of years, as the other nine filters could pick up the extra filtration needs. During the planning of the refurbishment of this filter, another filter presented with the same underdrain issue. This resulted in the decision to replace all filters in Plant A with new coatings. This decision was to proactively upgrade the filters, rather than waiting for each of the filters to fail, potentially causing catastrophic consequences for the community’s drinking water supply.
44
pump industry | Autumn 2022 | Issue 39
What did the upgrades involve? Bore Water to both plants
Prior to the upgrades, only water from the Lachlan River could be treated in both plants, and bore water could only be treated through Plant B, due to the inlet configuration. The recent upgrades and modifications to the inlet pipework enable bore water to be treated through both plants.
Filter Upgrades
Upgrades to Plant A began in 2019, when one of the filters was rebuilt. Since then, all ten filters have been reconstructed with the extra capability for constant online turbidity monitoring of each filter. A new concrete coating for all filters was part of the upgrades, in order to protect the integrity of the concrete filler bays and provide an extended life expectancy for at least 30 years. Intercrete was chosen as the Five Part Coating System for the solution, and Sydney’s Mattioli Bros applied the coating, which will allow for annual high pressure wash cleaning for filter maintenance. In 2021 the Plant A filters were also refurbished. This work followed a similar process to the Plant B works, however it also included the removal and replacement of the Filter roof. The old roof, containing asbestos, was removed to allow for the launders and underdrains removal and a new, larger roof was installed. The new roof now covers both A and B plant filters and contains new LED lighting to enable operators to clearly see water quality.
High Lift pumps
Murray Engineering was engaged via tender to supply and upgrade three high lift potable water supply pumps to feed the town’s reservoir from the treatment plant. The existing technology was installed around 1978 and was well past its
www.pumpindustry.com.au
