According to Ye Xiaoyan, the reporter of this newspaper, in early spring of 2016, a wetland park with clean water, fresh flower and grass will show beside the corn field in the north of Ximafang Village, Shangzhuang Town, Haidian District. However, it is not an ordinary park under which there is an underground reclaimed wastewater treatment plant with the daily handling capacity of 80,000 tons. It is the first underground reclaimed wastewater treatment plant under the pilot run in Beijing.

Generally, the reclaimed wastewater treatment plant reminds people of indescribable smell and loud rumbling sound. Walking into Daoxianghu Lake Reclaimed Wastewater Treatment Plant, you will see a park. Although the construction inside the park has not been completed yet, a rough outline has been formed. A zigzag pedestrian trail divides the part into two parts. In the northern part, the round pool forming a ring will be watered and planted with aquatic plant; in the southern part, the pine trees stand straight and the peach blossom awaits for flowering. “If you don’t observe carefully, It is difficult to see that the terrain of the park shows high east and low west. Once the water is poured, it will display a stream landscape from east to west ”, the project director of Beijing Enterprises Water Group, Liang Chao, said.

It is no need to transfer the water to the wetland. The water can be produced underground. Liang walked along the glass passage besides the wetland park and said, “The designed floor area is 17 hectare and it is overground; then it is designed as the underground form and covers 4.66 hectare, saving 70％ of the land area ”, while bringing the reporter to the sewage treatment plant underground.

A 20-meter depth from underground floor 1 to underground floor 3 covers the whole process of sewage treatment. Any noise cannot be heard and there is no special smell. The first step of sewage treatment is to filter the solid pollutant in the sewage water via the coarse screen in which the foul smell is emitted easily. However, the coarse screen is covered by the glass cover and the dedicated exhaust pipeline is connected. “The foul smell need collecting and handling to ensure it cannot be emitted”. During the sewage treatment, generally, the buzzing noise from the air blower sounds. However, this plant adopts the air suspension blowers with the aircraft engine technology and it is covered with the glass cover, therefore, the noise cannot be heard at all. Liang said, “The sewage treatment equipment is underground; the foul smell, the noise even the sludge are absorbed underground. Therefore, it will not influence the surroundings and the lives of residents.”

After the advanced treatment, the effluent quality from the Daoxianghu Lake Reclaimed Wastewater Treatment Plant can meet the water quality requirement for Surface Water Category IV. The water can be directly connected with the reclaimed water pipeline of the water plant and can be directly delivered to wetland park by the specially designed pipeline. Besides, it can supply heat for the buildings of the water plant via the heat exchange technology, both saving energy and protecting environment.

Daoxianghu Lake Reclaimed Wastewater Treatment Plant mainly undertakes the sewage treatment for the surrounding area within about 67 square kilometers, including Yongfeng, Aerospace Town, Life Science Park, hot spring, Cuihu Science and Technology Zone, Lengquan and Nan’an River. The daily handling capacity in the project Phase I is 80,000 tons; after the Phase II is completed, the total handling capacity will reach 260,000 tons/day.

“The wetland park of the plant not only provides a leisure facility, but also builds the badminton court and basketball court for free after they are completed in the preliminary plan.” Liang said.