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Support the improvement of air quality in Hong Kong

The 35 million m3 landfill site in Nent is a key element in Hong Kong's waste management. To meet the ever stricter environmental requirements of the Hong Kong government, Nent has adopted the most advanced landfill technology available. SUEZ has operated this landfill site since 2003, turning it into one of the best models in the world for biogas recovery and reuse!

The mission

Design, build and operate one of the largest landfills in Hong Kong

The world’s second economic power, the Middle Kingdom, is the largest producer of waste worldwide. In 1994, the Hong Kong government entrusted SUEZ with designing, building and operating the NENT (North East New Territories) landfill site.
 
In June 2003, a second contract, for a period of 25 years, was signed with Towngas, the local gas distributor, for the development of a landfill gas treatment system. The biogas thus captured is intended to be used on-site (gas and electricity) and off-site.
 
The mission entrusted to SUEZ comes under the high environmental requirements of the government in Hong Kong to improve the air quality and limit greenhouse gas emissions. It includes the implementation of work to refurbish the landfill sites for a period of 30 years.
 
35
million m3
The total capacity of NENT, one of the key waste processing sites for Hong Kong
110
ha
Surface area of the site, including 63 ha allocated to landfill
Our answer

Produce green energy, preserve resources

For NENT, Suez has designed and built facilities meeting several purposes:
  • secure containment,
  • landfill gas processing and its transformation into biogas,
  • processing of leachate produced by the natural fermentation of waste
  • continuous monitoring of the environmental parameters.
 
NENT is one of the best examples of the recovery and reuse of “green” energy in the world.
 
A secure containment facility
The cutting-edge system set up avoids:
  • the release of methane into the air,
  • nauseating smells,
  • the risk of leachate overflowing into the water tables.
 
It incorporates high-density, multi-layer composite coating systems covering the entire surface of the landfill site, complete leachate collection and processing equipment. The latter contains the biogas and the liquid leachate laden with organic matter and trace elements produced by the natural fermentation of the waste.
 
Landfill gases recovered
The anaerobic degradation of waste in a landfill environment produces biogas. Once collected, this is used as a renewable energy source for heating the leachate processing station. It is also used to generate electricity for the site.
 
Controlled water management
Water management is one of the key tools in integrating the site into its environment.In case of rains or typhoons, uncontrolled water flow can cause flooding and crop damage.For this reason, SUEZ continuously monitors and analyses many environmental parameters.
 
The results
After dehydration and treating the CO2, the remaining biogas is transported by a 19-km long pipe. Towngas uses it as fuel in its coal gas production process which supplies the gas network of the Chinese metropolis.
 
The recovery of landfill gas and its use for energy generation or as a fuel gives the NENT landfill site a real ecological dimension. It is the first landfill site to have ISO 9001 certification in Hong-Kong.
67,000
tonnes
of waste buried per month
25,000
m3
of biogas processed and delivered to Towngas each day
1,000
m3
of leachate processed each day 
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