Editor's note: This year marks the 20th anniversary of President Xi Jinping's proposal of the concept that "lucid waters and lush mountains are invaluable assets". China Daily will present a series of stories on how resources such as mountains, rivers, lakes, forests and farms are being transformed into priceless gifts.

Among dozens of large tributaries of the Yangtze River, the Chishui distinguishes itself as particularly unique. It is the only tributary that has not been dammed along its main course, and serves as a haven for over 160 fish species, playing a crucial role in the biodiversity of the Yangtze basin.

Yet, its ecological significance is paralleled by its economic importance, as its banks are lined with the country's most baijiu distilleries, earning it the nickname "liquor river".

This makes the Chishui a pivotal testing ground for the harmonious integration of development and conservation, embodying the core spirit of the concept of "lucid waters and lush mountains are invaluable assets", proposed by President Xi Jinping two decades ago.

To date, regions along the river have responded admirably to the test. The ecological environment of the Chishui has seen significant improvement, while the local baijiu, or white liquor, industry continues to thrive.

Flowing for over 400 kilometers, the Chishui rises in Southwest China's Yunnan province and joins the Yangtze in Sichuan province, but its longest stretch is in Guizhou.

The section of the Chishui in Guizhou's Renhuai county is one of the areas with the highest concentration of baijiu distilleries.

The production of sauce-aroma baijiu, which necessitates high fermentation temperatures, peaks in summer. Consequently, significantly more wastewater is generated during the hotter months.

In response to the seasonal challenge, the Renhuai government has bolstered its efforts to enhance baijiu wastewater treatment capacity, achieving a notable daily capacity increase of 13,000 metric tons in 2023. An intelligent system has also been introduced to improve wastewater processing management.

According to Lu Jun, an employee at Renhuai Water Affairs Co, the system can show in real time the exact amount of wastewater discharged by baijiu distilleries, the influent and effluent volumes of each of the 12 wastewater treatment plants, as well as data on key water pollution indicators.

The system automatically alerts maintenance personnel to any emerging issues, he said. The design of the network means that the workers can halt the flow of wastewater, and close relevant drainage outlets that discharge into the Chishui to ensure that no untreated water leaks into the river.

"Typically, all wastewater is treated on the same day it is generated to a quality reaching national standards for discharge into the environment," he said.

High concentrations of wastewater and elevated temperatures can, however, diminish the processing capacity of treatment facilities, he said. To address potential risks, storage pools with a total capacity of 40,000 cubic meters were built to accommodate wastewater that cannot be treated immediately.

In 2021, the Renhuai government launched a campaign to phase out or upgrade outdated baijiu production capacity, and merge small distilleries with inadequate pollution control facilities, decreasing the number of baijiu distilleries in the county from 1,925 to 868.