The Integrated Waste Management Facilities (IWMF) aims to substantially reduce the bulk size of mixed MSW and to recover useful resources. It will minimize the landfilling of waste significantly, thereby extending the useable life of landfills and their extensions in Hong Kong.
The IWMF will be developed in phases. The IWMF Phase 1 will have a treatment capacity of 3,000 tonnes each day. It will adopt advanced incineration as the core treatment technology as well as a demonstration scale mechanical sorting and recycling facility for recovery of useful resources from the mixed MSW.
Advanced technologies are able to reduce pollutant emissions from incineration effectively. For example in Germany, the amount of waste incinerated in year 2000 doubled that in 1990, but due to the adoption of advanced control technologies, the dioxin emission was only one-thousandth of that in 1990. Overseas experience and studies have also demonstrated that advanced incineration plants that comply with stringent emission standards will not cause adverse health impacts.
The IWMF Phase 1 will adopt state-of-the-art technologies and pollution control measures. Its emissions will comply with the emission standards for waste incineration facilities in Hong Kong and the European Commission for the protection of public health and the environment. The emission standard for nitrogen oxides will be even more stringent than the corresponding European Commission standard.
Air quality monitoring stations will be set up at Shek Kwu Chau (SKC), Cheung Chau and South Lantau to provide objective data on local air quality to ensure that the operation of the IWMF Phase 1 will not affect the surrounding environment. An action level will be set at 95% of the emission limits to provide early alarm such that we will take appropriate actions according to a formulated plan which will include ceasing the MSW feeding and preparing for shut down of the incineration system.
For the artificial island near SKC, MSW compacted in tightly sealed containers and delivered by dedicated container vessels would be delivered by marine vessels from the existing refuse transfer stations including Island East Transfer Station, Island West Transfer Station and West Kowloon Transfer Station. For the Tsang Tsui Ash Lagoons site, MSW currently delivered to the berth of WENT Landfill by marine vessels or delivered directly to the WENT Landfill by land transport will be diverted from the WENT Landfill to the adjoining the Tsang Tsui Ash Lagoons site by land transport.
IWMF Phase 1 Contract
The Design-Build-Operate (DBO) contract for the IWMF Phase 1 was awarded in November 2017. The IWMF Phase 1 is expected to be fully commissioned by 2025 and the contract includes a 15-year operation period.
Key features of the DBO contract:-
design and construction of reclamation of about 16 hectares to form an artificial island near SKC and related works;
design and construction of an MSW incineration plant with a maximum treatment capacity of 3,000 tonnes per day;
design and construction of a mechanical sorting and recycling facility with a maximum treatment capacity of 200 tonnes per day;
design and construction of associated architectural, building, civil and landscape works;
design and installation of the electrical and mechanical works for the waste receiving and sorting facilities, waste incineration, heat recovery, power generation, pollution control and ash treatment systems;
design and construction of mechanical and electrical works for utility services facilities including a desalination plant and a wastewater treatment plant.;
design and construction of power connection and export system; and
provision of pollution control and environmental monitoring facilities.
Environmental Education Facilities
The IWMF Phase 1 will have environmental education facilities that provide information on and demonstration of waste management in Hong Kong for the public. Drawing on experience from the T·PARK, guided tours will be provided to visitors for understanding the most advanced waste-to-energy technologies and appreciating the environmental features of the IWMF Phase 1.
An educational route will be designed for visitors to overlook the main components of IWMF Phase 1 and have a close-up learning experience at key areas such as the incineration process, flue gas treatment process, mechanical sorting and recycling facility and control room. Ferry services between the IWMF Phase 1 and Central/Cheung Chau will be offered to visitors.
Environmental Protection and Ecological Enhancement
The IWMF Phase 1 will recover heat energy from the MSW incineration process to produce about 480 million kilowatt-hours (kWh) of surplus electricity (amounts to about 1% of the total electricity consumption in Hong Kong) for export to the existing power grid in Hong Kong every year. The surplus electricity, which is equivalent to the output of 400 largest solar farms in Hong Kong at Siu Ho Wan Sewage Treatment Works, will be sufficient for use by 100,000 households.
Through the replacement of fossil fuel in electricity generation and reduction in the volume of MSW for landfill disposal, it is estimated that about 440,000 tonnes of greenhouse gas emission per year can be curtailed.
Baseline Monitoring Surveys
Before the construction works of the IWMF Phase 1 starts near SKC, baseline monitoring surveys for Finless Porpoise, White-bellied Sea Eagle and hard coral have been conducted to determine their baseline conditions to ascertain the utilisation of the area by Finless Porpoise, the presence and breeding status of White-bellied Sea Eagle in the Shek Kwu Chau area and the number and location of hard coral colonies within the potentially affected areas according to the approved Environmental Monitoring & Audit Manual. These baseline monitoring surveys have been used to formulate the coral translocation plan and the detailed monitoring programme and mitigation measures to avoid disturbance to Finless Porpoise and White-bellied Sea Eagle during construction and operation.
The artificial island near SKC will mainly be constructed by non-dredged method to minimize water quality impact. The marine deposits underlying the reclamation, including the seawalls and breakwaters, will be left in place to avoid dumping of dredged marine deposits.
An advanced ground treatment method, i.e. deep cement mixing (DCM) is proposed to reinforce the marine mud in situ to control settlements and movements of the reclamation to within acceptable limits and to ensure that the construction of the artificial island can be completed within a reasonable time frame.
The DCM will also be designed to ensure that the reclamation will be safe and any residual settlements and movements will not affect the operation and service of the IWMF Phase 1. Precast concrete structure will be used for the seawall and breakwater construction to minimize underwater acoustic disturbance to Finless Porpoise and water quality impacts during construction.
The blockwork seawall facing Shek Kwu Chau will be designed as environmentally friendly eco-shorelines with features to provide more suitable habitats for colonisation of intertidal and subtidal species and thereby enhance the ecological functions of the coastal habitats.
Net Zero Wastewater Discharge
The IWMF Phase 1 will be designed with a net zero discharge of wastewater by equipping with a wastewater treatment plant on-site to provide treatment to wastewater generated from the facilities for reuse in the incineration plant and the mechanical sorting and recycling facility or for washdown and landscape irrigation in the IWMF Phase 1.
Mechanical Sorting and Recycling Facility
The mechanical sorting and recycling facility will make use of automatic waste sorting technology to recover useful resources, such as ferrous metal, non-ferrous metal, plastics and glass, from up to 200 tonnes of MSW per day.
During the incineration process, the non-combustible residue of combustion in the incineration system, i.e. bottom ash, will be collected and magnetic separators will extract ferrous metals from the bottom ash for recovery. Opportunities for recycling or other beneficial use of the bottom ash will be further explored during the design and construction period.
Architectural and Landscaping Design
The architectural and landscaping design of the IWMF Phase 1 will embrace the environmental philosophy of "Green, Clean and Lean" so as to blend in with the surrounding environment. We will also strive to acquire the green building rating accreditation of BEAM Plus Gold or a higher rating for the project.
To enhance communication with the community in a proactive way, Keppel Seghers – Zhen Hua Joint Venture (KSZHJV) set up Community Liaison Groups (CLG) in 2018. The CLG shall comprise members from KSZHJV, Shek Kwu Chau Treatment & Rehabilitation Centre, The Society for the Aid and Rehabilitation Drug Abusers, Cheung Chau Rural Committee, Fishery Sector, South Lantau Rural Committee, Representatives of Indigenous inhabitant, Island District Council and Island District Association. The KSZHJV leverages on the CLG to exchange views with the community on the latest project developments. In addition, the CLG is also platformed for the KSZHJV to update the community leaders and listen to their views on various topics related to Integrated Waste Management Facilities, Phase 1 including the environmental issues.