Chongqing- Southwest China's Chongqing has set up intelligent water quality monitoring stations at the sewage discharge outlet of the Yangtze River, monitoring ammonia nitrogen, nitrogen, and phosphorus in real time and providing early warning information.

Water is key to a range of industrial and engineering processes, from chemical and material production to agriculture. Few sectors do not rely on water in their value chain, but these same processes fill water with pollutants. According to UNESCO, over 80% of the world's wastewater is released into the environment without treatment. Almost every industry has a combined interest in finding innovative ways to monitor and treat wastewater.

Chongqing is the first city in China to pilot the renovation of sewage outlets in the Yangtze River. These sewage outlets are the last gate for pollutants to enter the river.

For example, the Xiaojiagou reservoir in Chongqing Liangjiang New Area is connected to the Tiandun River, a tributary of the Jialing River. It covers 1.6 square kilometers, with a green shore and clear water. But a few years ago, the water was severely eutrophicated due to urban pollution.

The change came three years ago when the local government integrated sewage discharge control, pipe network construction, ecological restoration, and river basin treatment.

"We have improved the pipe network, storm detention tank, and wetlands, and the water quality has been improved significantly," said an official from the Chongqing Ecological Environment Bureau.

In recent years, the government has mapped the sewage outlets covering coding, coordinates, traceability, monitoring, and other information. If anything is abnormal, they can trace the source and control the source of the watershed.

The storage pool and monitoring station are set aside in the reservoir, which is a key to controlling sewage outlets. The storage pool will discharge the rainwater early into the sewer pipe through intelligent monitoring. It will only collect rainwater in the later stage and release it into the reservoir.

As of September this year, there were 30 automatic water quality monitoring stations in Liangjiang New Area.

The monitoring room of Jinjiahe Yard station, located near Dongliang River, a tributary of the Yangtze River, is also a smart application. A row of online water quality automatic monitors are working, which can monitor indicators of ammonia nitrogen, nitrogen, and phosphorus at any time.

"It collects water for monitoring and analysis every hour and automatically uploads data," said an official from the Chongqing Ecological Environment Monitoring Center. "The water quality of this section has been stable for a long time to reach class Ⅲ, confirming the effect of water pollution prevention and control in the basin."

Chongqing has 164 monitoring sections, 98 of which are equipped with automatic water quality monitoring stations. Next, Chongqing plans to build a superstation on the mainstream of the Yangtze River.

Data shows that, from January to August 2022, the water quality of the Chongqing section of the Yangtze River continued to be classified as Class II and can be used as a drinking water source. Besides, 97.3% of state-controlled river sections see excellent water quality.