Water-Energy Nexus of Urban Water Systems for Chengdu’s Low-carbon Blueprint
This report takes Chengdu’s low-carbon development and water pollution emissions reduction goals as its starting points and analyzes the current energy efficiency of its municipal wastewater treatment facilities. It uses scenario analysis to forecast the potential for energy conservation of Chengdu’s municipal wastewater treatment facilities and makes recommendations on how to improve the energy efficiency of WWTPs in order to help Chengdu achieve its low-carbon city target.
One of the indispensable aspects of China’s urbanization is the construction of urban water infrastructure (including water supply, wastewater treatment and recycling). As water pollution worsens it puts even more pressure on urban water pollution control and wastewater treatment facilities. Whether a city develops by upgrading and improving its wastewater treatment facilities or builds new facilities, both lead to a rapid growth in energy intensity for the urban wastewater treatment system and both pose new challenges for the low-carbon and sustainable development of a city.
Through a case study from Chengdu, a city facing with increasing water pollution problems, the key findings are found below:
1） Water conservation will help Chengdu decrease 5% energy consumption of the wastewater system by 2030. Integrated energy management of wastewater treatment facilities will bring further decrease of the energy consumption at 20%-45%.
2） Reclaimed water will make up 45% of water used for public services while energy conservation will save 20% of the energy consumption increase caused by usage of reclaimed water in Chengdu.
3） Upgrade of wastewater treatment facilities is a must for Chengdu to reach its pollutant emission reduction targets.
4） Integrated energy management will help saving 70 million – 150 million kwh energy consumption for Chengdu’s wastewater system.
5） Low carbon sludge treatment will be one of the effective measures for the low carbon development of Chengdu’s wastewater system.