​Cover News | How can Reclaimed WWTP bring wastewater back to life?

"The annual cost of treating wastewaterin a large city is 1.6 billion yuan."

The city we live in generates daily domestic wastewaterthat is collected in Reclaimed WWTPand treated through physical, biochemical and other methods before being reused. So, how does a Reclaimed WWTPwork? What high-tech methods are there for modern sewage treatment?

In Tianfu New Area of Chengdu, beneath the lush living water park, there is actually a WWTPcovering an area of over 30 acres - the First UndergroundReclaimed WWTPof Tianfu New Area.

The First Reclaimed WWTPin Tianfu New Area

Building the WWTP underground

The total water storage capacity of the Earth is 1.45 billion cubic kilometers, with 2.5% being freshwater. 70% of the freshwater is frozen in the ice sheets of Antarctica and other places, while the rest is in the soil and deep underground. Less than 1% of the available freshwater accounts for approximately 0.007% of the total water volume.

In order to make reasonable use of sewage, as the first proposed "park city", Tianfu New Area adopts the technology concept of Distributed UndergroundReclaimedWWTPof China Water Environment Group, which is "environmentally friendly, land intensive, and resource utilization". It integrates environmental pollution control and park city construction, achieving "one land, three floors, and multiple uses".

The wastewatertreatment is completed underground, with the construction of landscape water parks, sports fields, children's entertainment facilities, etc. on the ground, occupying only one-third of the traditional ground WWTP. Currently, the project can process 50000 tons of wastewaterper day. The purified water will be reused. "The reclaimed WWTPcan provide ecological replenishment water for the Luxi River and Xinglong Lake every year, as well as water for flushing toilets, greening, fire protection, etc. in Tianfu New Area, improving the ecological water environment of Science City and saving water resources," said the science popularization personnel.

Visiting the Water Environment Science Museum by Zhang Zheng

How can a reclaimedWWTPregenerate wastewater?

As the first underground reclaimed WWTP in Chengdu, how can the first reclaimed WWTPin Tianfu New Area regenerate wastewater? The regeneration of sewage has three stages.

Firstly, use a coarse grid to intercept floating garbage, then use a fine grid to intercept garbage fragments and slightly larger gravel, then remove most of the sand through a sedimentation tank, and then use a fine grid to remove finer garbage.

The second step is to degrade and decompose pollutants in the sewage treatment plant through microbial communities, effectively removing phosphorus, nitrogen, organic matter, etc. from the water.

The final step is to further treat the biochemical treated water, which is then subjected to ultraviolet radiation to kill bacteria in the water. Ozone achieves sterilization through the oxidation of oxygen atoms, and activated carbon filters out free substances, microorganisms, and some heavy metal ions in the water, reducing the color of the water and further removing harmful substances to the human body. This allows it to be reused and become recycled water.