A project in Tianhe District of Guangzhou City was selected into the first batch of recommended list of typical cases of pollution reduction and carbon reduction in "waste-free city" in 2023
Recently, the Asia-Pacific Regional Center for the Basel Convention announced the first batch of recommended list of typical cases of pollution and carbon reduction synergy in "waste-free cities" in 2023. A total of 36 recommended cases in 6 major fields have been selected across the country. Among them, the case of "Application of Green and Low-Carbon Low-Temperature Vacuum Dehydration and Drying Integrated Technology in the Sludge Drying Treatment Service Project of Guangzhou Daguan Water Purification Plant" recommended by Tianhe District of Guangzhou City, Guangdong Province is the only selected case in Guangzhou City and the only selected case in the province in the fields of construction waste and other solid waste.
According to reports, under the guidance of the Guangzhou City Ecological Environment Bureau, in recent years, Tianhe District has vigorously promoted the source reduction, resource utilization and harmless treatment of solid waste, helping to accelerate the comprehensive green transformation of economic and social development. A number of excellent "waste-free institutions","waste-free cultural and business travel complexes","waste-free schools","waste-free farms","waste-free factories", etc."Waste-free cells" bloom at many points and have fruitful results. Daguan Branch of Guangzhou City Water Purification Co., Ltd.(hereinafter referred to as Daguan Water Purification Plant) is one of the outstanding representatives of "waste-free factories."
Driven by innovation, maximize sludge reduction
It is understood that the plate and frame filter presses and stacked screw filter presses commonly used in water purification plants can only compress the moisture content of sludge to 60%-80%. Sludge with high moisture content is not only difficult to effectively compress, but also easy to cause environmental pollution.
In response to this problem, Tianhe District encourages Daguan Water Purification Plant to adopt the BOT (Build-Operation-Transfer) model for construction and operation, and at the same time introduces low-temperature vacuum dehydration and drying integrated technology. This technology uses the principle of reducing the boiling point of water by reducing environmental pressure, and creatively combines mechanical pressure filtration and dehydration with vacuum drying technology to reduce the sludge moisture content from 97% to 30%-40% at a time, maximizing the reduction of sludge.
The treated sludge is transported to power plants, cement plants and other utilization and disposal units using fully enclosed sludge trucks, and used as incineration power generation fuel and building materials, helping to make sludge disposal harmless and resourceful.
Sludge disposal flow chart
Recycling to effectively reduce carbon emissions
As a buried water purification plant, Daguan Water Purification Plant can only use electricity as energy source. However, the traditional electric hot water boiler generates 85 ° C hot water with high energy consumption, high carbon emissions, and has energy waste problems.
In response to this pain point, Tianhe District actively guided it to innovate the use of water source heat pump technology, using the reclaimed water treated by the water purification plant as a heat source for sludge drying according to local conditions, realizing the resource and energy conversion of reclaimed water, and at the same time significantly reducing system operating costs, energy consumption and carbon emission intensity.
According to statistics, using new technology to post-treat each ton of sludge (based on a moisture content of 80%) can reduce carbon emissions by about 190 kilograms, and when operating at the design load, carbon emissions can be reduced by 31.2 tons per day.
Water source heat pump applied to sludge drying projects
Diversified communication and deeply rooted in the concept of "waste-free city"
In conjunction with the creation of a "waste-free city", Tianhe District guided Daguan Water Purification Plant to actively create a "waste-free" concept atmosphere, set up a "waste-free" series of promotional posters, broadcast theme promotional videos, rolling theme subtitles, etc. in the factory area, carry out "waste-free" special training,"waste-free" concept knowledge competitions and theme markets, and promote the diversified dissemination of "waste-free culture."
During themed festivals such as June Five-Year Plan Environment Day, relevant departments of Tianhe District cooperated with schools and communities around the factory to carry out ecological and environmental science popularization research activities, allowing students to personally visit the water purification plant and organize science popularization volunteers to come to the masses. Through entertaining and face-to-face lectures, more citizens can understand the construction concept of "waste-free city" and actively participate in water-saving, water-protection, ecological and environmental protection actions.
"No Waste" Concept Knowledge Competition
In the next step, Tianhe District will continue to strengthen policy guidance and technical support, encourage more units to participate in the construction of "waste-free", promote the formation of a number of replicable and replicable demonstration projects, and help Guangzhou's "waste-free city" construction.
