the 11theco forum global guiyang 2021 was held in guiyangon july 12, which wasthemed“green and low-carbon development, fostering a community of life and man and nature”. as a role model of river treatment in guiyang, the nanming river has received widespread attention.

ahard nut to crack

the nanming river, mother river of guiyang, is a tributary of the wujiang river and merged with the yangtze river. as a key ecological barrier in the upper reaches of the yangtze river, it boasts a total length of 219 kilometers, of which 185 kilometers runs through guiyang city. at the end of the 20th century, the nanming river was subject to serious pollution due to the rapid growth of population and economy. citizens were suffering and the treatment of the nanming river became an urgent issue.

water treatment is a worldwide problem. long distance, dense population, and heavy pollution. this is no proven experience to follow regarding the treatment of the nanming river. people used to follow the century-long centralized treatment method in the west, collecting and transporting sewage to the downstream for centralized treatment. however, it would result in insufficient ecological flow, poor self-purification capacity, and the overloading of sewage interception ditch and plants. rivers easily get black and stinky and come to a deadlock of “repeated treatment and repeated pollution”. in addition, long-distance transportation through sewage pipe networks is also vulnerable to leakage and environmental risks.

it has become a key issue regarding how to design the collection, treatment and reuse of sewage, and how to use the treated water as a stable water resource in the city.

city-wide treatment

the nanming river is not only a river, but also a landscape in the city and an activity center to people. the key is to transform our mindset and planning. we need to implement river treatment across the entire city.

       “we conducted a systematic study on the status and trends of the nanming river 9 years ago. we spent 6 months on investigation along the branches and tributaries of the nanming river and figured out the source of pollution. finally, we’ve proposed the principle of appropriate concentration, on-site treatment, and local reuse. the distributed underground reclaimed water ecosystem is actually an innovative technology system for sewage treatment and resource utilization”, said cweg president dr. feng hou.

the city acted according to a unified arrangement and strategic plan and completed a city-wide ecological system. guiyang has built 16 new distributed underground reclaimed water plants and upgraded 5 plants along the nanming river to facilitate urban drainage, functional zoning and resource utilization.

according to kong hainan, chair professor, school of environmental science and engineering, shanghai jiao tong university, “the distributed underground reclaimed water ecosystem can adapt to the local condition of river channels and be built in the upper and middle reaches. the system can not only replenish ecological water but also eliminate the black and stinky water. it considers sewage treatment, reclaimed water reuse and comprehensive treatment of rivers as a whole.”

international river treatment model projects, the kamo river in kyoto, japan, and the cheonggyecheon river in seoul, south korea, were completed by single water plants. while the nanming river project has taken into account all seven tributaries to serve more than 5 million citizens. we can hardly find any similar projects around the world in terms of the technology and scale.

ecological product value-realization mechanism

china strives to set up and improve the mechanism to realize the value of ecological products and find a new approach to ecological conservation and green development. on april 26, 2021, the general office of the communist party of china central committee and the general office of the state council jointly issued theopinions on establishing and improving the value realization mechanism of ecological products.

the distributed underground reclaimed water ecosystem not only effectively avoids neighbor disputes but also benefits citizens. for example, theguiyang qingshanunderground wastewater treatment planthas turned the above-ground space into a science museum and a scenic park. these facilities help advocate water conservation education and function as a leisure room for citizens.

professor li hongwei, director of the ecological civilization teaching and research office, social and ecological civilization teaching and research department at the central party school of the communist party of china, said, “it’s about delivering high-quality ecological products to surrounding residents. academically, the practice is known as the realization of ecological product value. the underground reclaimed water treatment plant has turned the black and smelly nanming river into high-quality ecological products and brought ecological benefits to citizens. it has realized the cultural and social values of ecological products.”

the economic value of the system is also obvious. the traditional above-ground sewage treatment plant is unsustainable due to long-distance pipeline network and costly sewage treatment mode. it is prone to neighbor disputes and economic burden. the distributed underground reclaimed water ecosystem not only reduces the overall cost of sewage treatment, but also makes full use of water resources. the 21 underground reclaimed water plants distributed along the nanming river play a key role in replenishing ecological water.

professor li hongwei said, “according to our study on wastewater treatment and reclaimed water reuse of the nanming river project, we’ve noticed that the system also makes a great contribution to carbon emission reduction and carbon neutrality.”

the city has realized green development through the recycling of reclaimed water. the underground reclaimed water ecosystem helps reduce carbon emission and free up more ground space for landscapes. efficient land and water utilization can not only serve the goal of carbon neutrality but create synergy between pollution mitigation and carbon reduction.

uk spends nearly 100 years and tens of billions of pounds on treating the thames river; while guiyang only takes 8 years and spends rmb 7.6 billion on the treatment of the nanming river. in 2020, the water quality of nanming river remained class iii for more than 5 months. no river dredging is required for 7 years. a black and stinky nanming river has been restored to what it was: clear waters, green banks, lively fish and flying white egrets. (wen yuan, all-media reporter of guangming daily)


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