Issue 15, Apr 2021
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Issue 15, Apr 2021
Water is a precious resource. To further enhance water security, the Hong Kong SAR Government has been exploring water sources that are not susceptible to the impact of climate change, such as recycling grey water, alongside ongoing water conservation efforts. Indeed, the Chief Executive’s 2017 Policy Address proposed a 10% reduction in Hong Kong’s per capita fresh water consumption by as early as 2030, using 2006 as the base year.
A milestone project in this drive is the Grey Water Treatment Plant (GWTP) at the Anderson Road Quarry (ARQ) Development in East Kowloon. ATAL is delighted to be taking part in this project, the first district-wide centralised grey water recycling system in Hong Kong. The GTWP will treat the grey water collected from households in the ARQ Development and then supply the treated grey water for toilet-flushing and other non-potable purposes in the development area. With a maximum treatment capacity of 3,300 cubic metres per day which is equivalent to 1.32 Olympic-size pools, the GWTP will serve a planned population of about 25,000 in the ARQ Development.
Grey water is lower grade water collected from baths, showers, wash basins, kitchen sinks and laundry machines, etc. Noting the high elevation of the ARQ Development, grey water can be treated at the GWTP and used for toilet-flushing and other non-potable uses to save energy from pumping seawater from the sea front and reduce the amount of treated sewage effluent discharged, minimising the negative impacts on the environment.
For biological treatment and filtration, which remove organic matter and other pollutants, this project uses Membrane Bioreactor (MBR) which employs membranes to filter suspended solids in the grey water with biological processes to enhance the quality of treated grey water. Chlorine disinfection is employed as the last treatment step to ensure the safe and high quality of the final discharge.
“ATAL has extensive experience in developing, deploying, operating and maintaining wastewater and sewage treatment solutions for Hong Kong, Macau, the Mainland and Asia,” noted Ir Raymond Chan, Executive Director of ATAL Engineering Group. “Our expertise in MBR systems, an advanced treatment technology at the heart of this GWTP, makes us uniquely qualified for the project.”
ATAL’s involvement in the GWTP project covers the design, supply, delivery, installation, process start-up and testing and commissioning of the inlet works, the pre-treatment system, the MBR system, the chemical system, the sludge thickening system and other ancillary works.
With an impressive MBR jobs portfolio, including MBR plants for the Macau Industrial Zone Waste Water Treatment Plant, the Yung Shue Wan Sewage Treatment Works and the Hong Kong-Zhuhai-Macao Bridge Hong Kong Boundary Crossing Facilities Sewage Treatment Plant, with capacities at 12,000 and 8,550 and 2,700 cubic metres per day respectively, ATAL has proven expertise in applying MBR to diverse projects.
Although Hong Kong has been using seawater for flushing since the 1950s, there are areas outside of the seawater supply zone where fresh water is still used. Re-using grey water to replace fresh water for flushing in those areas could be a promising way to conserve fresh water.
“Grey water recycling provides a cost-effective and sustainable solution.” said Ir Chan. “We look forward to contributing towards building a more diverse water supply system for Hong Kong, with enhanced water security, reliability and resilience.”
Left: The 3D-model of the grey water treatment plant
Middle: Grey water collected from households in the new ARQ Development will be treated for flushing
Right: The plant will serve around 25,000 population residing in ARQ Development after completion