I refer to the letters by Martin Williams ("Officials have failed to convince public about merits of incinerator", May 1) and Charlie Chan ("Incineration plans are outdated", May 10) and the columns by Philip Bowring ("The politics of self-interest rules in Hong Kong", May 4) and Howard Winn in Lai See ("Waste matters", May 3).
The thermal treatment technology to be adopted for Hong Kong's first integrated waste management facility for municipal solid waste (MSW) near Shek Kwu Chau has been subject to a lengthy and thorough review process covering, for example, advanced moving grate, gasification and plasma gasification. Advanced moving grate was chosen because it is still the mainstream waste treatment technology adopted worldwide for large-scale MSW treatment. It has merits on environmental performance, reliability, operation adaptability and cost effectiveness.
It is incorrect to say moving grate is outdated. It has had continuous enhancements over the years and is still regarded as very reliable and robust to fully meet the latest European Union emission standards, which are the highest standards for modern incinerators in the world. In fact, over 90 per cent of new thermal treatment plants commissioned since 2009 used moving grate technology, including new plants being built, such as in Copenhagen.
Hong Kong's facility will also adopt state-of-the-art, advanced systems such as the selective catalytic reaction system to further reduce the emission of nitrogen oxides.
We are fully aware of those plasma gasification plants referred to by Winn. These plants are still under commissioning, construction or yet to be built.
Compared to the treatment capacity of 3,000 MSW [tonnes] per day we are planning, the plasma gasification plants are still relatively small, with very limited performance track record.
It would take several years of operation before the effectiveness and efficacy of those plants can be evaluated and established. We will closely monitor their development and take into account their actual operational experiences in future studies.
The environmental impact assessment concluded the operation of the modern incinerators will not have adverse impacts on public health. Recent international reviews show well-managed and regulated modern municipal waste incinerators do not pose a risk to public health.
The integrated waste management facility can help reduce the volume of municipal solid waste by 90 per cent, significantly reducing the use of landfill space, turn waste into energy and contribute to climate change mitigation.
Elvis W. K. Au, assistant director of environmental protection