| 51 Upgraded asset to come online INFRASTRUCTURE Matamata Piako District Council The filtered water flows through a two-pond aeration system, then a membrane plant and is finally discharged into the Mangawhero River. Richard Loader Budgeted at one million dollars, Matamata Piako District Council’s (MPDC) project to replace the filtration screen at its Matamata wastewater treatment plant is now in the closing stages of commissioning and is expected to be fully operational in early March. Located beside the wastewater ponds, the screen is designed to intercept and remove any non-biodegradable solids that might enter the wastewater during its journey to the plant. When the wastewater enters the wastewater plant it flows into a manhole chamber that has three pumps in it. The water is then pumped up through a 250mm diameter rising main, and into the filtration screen. Solids collected in the screen are dropped into a screw press, pushed up into a chute and dropped into a large waste hopper for disposal at landfill. The filtered water flows through a two-pond aeration system, then a membrane plant and is finally discharged into the Mangawhero River, which MPDC has a consent from Waikato Regional Council (WRC) to do. During routine maintenance it was discovered that the filters, which were due for renewal, were not functioning as effectively as they should have been and that some solid materials were getting through the mesh screens, compromising the treatment process and ultimately MPDC consent conditions. The existing filter has been replaced with two state-of-the-art inclined rotary screens imported from Germany. The same inclined rotary screen is currently being used in MPDC’s wastewater treatment plant in Waihou. The inclined rotary screens are designed to intercept and remove dregs, spiral lift and dewater. While both screens could operate in parallel, Matamata’s wastewater inflow is such that it would not warrant running two filters at once, so while one filter will remain on active duty, the other will be on standby and activated when the other is being serviced, ensuring efficiency and operational continuity. MPDC’s capital works projects Programme Manager, Andrew Hazelton, says that following a design process, the project works went out to tender with Brickhouse Technologies selected to supply the replacement screens, as well as undertake the installation and commission work. The new inclined rotary screens were ordered as soon as Brickhouse Technologies were awarded the contract, and arrived in time for the installation stage of the project. Operating throughout Australasia, Brickhouse Technologies are a leading water treatment and wastewater engineering company for both local authorities and industrial users. “Once Brickhouse Technologies was engaged we went through the process of engaging Camex Civil to undertake the civil work which included clearing the site, creating the wastewater diversion and temporary filters, building the new concrete pad and installing some new inlet pipework for the new screens. Given the size and weight of the two new filters, the new concrete pad that they sit on is quite a substantial rectangular structure measuring 13 metres by 6.4 metres, by 200mm thick, with two layers of reinforcing.” The civil work commenced in August and was completed end of October, when Brickhouse Technologies commenced the installation of the new screens. Andrew says supply chain issues resulting from Covid caused delays in importing “The project is now in the final stages of commissioning. The wastewater will be directed back into the new screen early February.” 400mm valves required for the project and this has impacted on the project’s timeline by about two months. “The project is now in the final stages of commissioning. “The wastewater will be directed back into the new screen early February, enabling fine tuning of the system, and programming of the PLC and the alarms, because much of the system’s functionality will be automated. The new system will be fully operational early March.” In addition to maintaining compliance with the Waikato Regional Council’s consent conditions enabling wastewater to be released into the Mangawhero River, the new filters that have a long operational life will deliver a range of benefits including operational efficiency and environmental protection.
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