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CTA Letter to EPD on Landfill Gas Levels in Hong Kong

From: EPD
Sent: 26 February, 2016
Subject: Query on current levels of Landfill Gas in Hong Kong

Dear Mr. Middleton,

Thank you again for your email dated 12 Jan 2016 regarding the use of LFG.

You may well understand that LFG is generated as a result of physical, chemical and microbial processes that undergo within the waste cells of the landfill. The processes and hence the generation rate would vary from time to time according to different waste intake history, environmental conditions (e.g. temperature, extent of leachate circulation), and configurations of the landfill site (e.g. landfill depth and thickness of cover material), etc. It is noted that the LFG generation at local landfills has been relatively steady over the past few years. In any case, we have been closely monitoring the management of the landfills to ensure landfill operations are in accordance with stringent environmental standards.

As you have already noted that it is a government policy to encourage utilization of LFG recovered from the landfill sites. Apart from on-site utilization at all three strategic landfills, there have been arrangements for off-site utilization at NENT and SENT landfills. In order to make best use of the LFG recovered, EPD has been working closely with the landfill contractor of WENT Landfill in exploring and identifying various practicable beneficial use of surplus LFG recovered at the landfill site. As part of our on-going effort, we have taken the liberty to pass on the information of overseas experience in your email to the contractor for reference/consideration.

May I thank you again for your interest in the Hong Kong environment, which is very much appreciated and important for the continual enhancement of our local environment.

H. S. Chan
for the Director of Environmental Protection Department


From: CTA
Sent: 12th January, 2016
Subject: Query on current levels of Landfill Gas in Hong Kong

Dear Gary

Thanks for your reply

In 2008 the LFG at the 3 sites collected was as follows: 26,600 m3 per hour

Obviously as the landfills get older and larger the LFG would normally increase but I note that the 2014 rate is 12.400/6,450/7,185 = 26,035 m3 per hour
which is lower than 2008, of which you state approx 80% (20,828 m3 per hour) would be beneficially used and the remainder (5,200 m3 per hour/ 124,800 m3 per day / 45,552,000 m3 per year)
is flared off.

That seems an awful lot of wasted methane and relevant pollution caused by the flaring. I understand methane is 21 times more damaging to the environment than CO2 but surely some better use
could be made of the gas ?

For example I note that companies like SITA promote liquid biomethane from landfill gas in UK and Europe – why not here too ?

Kind regards,
James Middleton


CTA Letter to Legco on Hong Kong Waste Management

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45,552,000 cubic meters of landfill gas is currently flared off per year from the 3 HKG open landfill sites

Download (PDF, 356KB)