Let sewage "regenerate", solve the problem of water shortage in the city

The utilization of sewage resources plays an important role in alleviating the shortage of water resources and improving the water environment and water ecology. In recent years, all localities have actively changed the concept of water use, increased the scale of recycled water utilization, expanded the use of recycled water, reduced the amount of fresh water taken from cities and the discharge of sewage, and promoted the mutual promotion of water conservation, pollution control and emission reduction. According to the preliminary statistics of the Ministry of Housing and Urban-Rural Development, in 2022, the national urban renewable water consumption reached 18 billion cubic meters, 4.6 times higher than 10 years ago.

Developing "second water source"

Realize sewage "regeneration" + photovoltaic power generation

"At present, the city's urban recycled water utilization facilities have been built 4, 2 under construction, recycled water production capacity of about 49,000 cubic meters/day, supporting the construction of recycled water utilization pipeline 12 kilometers."

The relevant person in charge of the housing and Urban-Rural development Bureau of Neijiang City in Sichuan Province said that in recent years, Neijiang City has taken recycled water as the city's "second water source", actively built recycled water plants, improved sewage treatment and recycling capacity, and alleviated the contradiction between the growing demand for water and the shortage of water resources. In 2022 alone, the urban area of Neijiang will use 16.54 million cubic meters of recycled water, with a utilization rate of 28.11%.

The Xiejiahe Recycling Water Plant, which was put into operation on June 30, 2022, is one of them. According to reports, the recent processing scale of the plant is 10,000 cubic meters/day, and the long-term processing scale is 30,000 cubic meters/day. At present, the treatment capacity has reached 8,000 cubic meters/day, and the "regeneration" of sewage has been realized.

"On the one hand, these reclaimed water can be used as ecological water replenishment to the nearby Xiejia River; On the other hand, it can be used for toilet flushing in public buildings such as sports centers and cultural centers, road surface flushing in urban streets, and green space watering in Xiejiahe Park and Xiejiahe Recycling Water Plant." Xie Jiahe recycling water plant technical management personnel said.

In fact, the Xiejiahe reclaimed water plant can not only "regenerate" sewage, but also be used for photovoltaic power generation to help save energy and reduce carbon. "The photovoltaic power generation system of Xie Jiahe Recycling Water Plant can generate about 110,000 KWH per year, and calculated at 0.65 yuan/KWH of electricity, it can save 71,500 yuan of electricity per year. In addition, by introducing advanced technologies such as energy-saving and environmentally friendly sewage source heat pump air conditioning, it can save air conditioning costs of about 56,000 yuan for the factory every year." The above technical management personnel said.

According to reports, the Dengjiaba recycling water plant under construction in Neijiang City has entered the stage of equipment installation and commissioning, and is scheduled to be put into trial operation at the end of June 2023. After the plant is completed, it will further expand the scope and scale of reclaimed water use in Neijiang City and reduce the pressure on industrial water use.

Improve the sewage treatment system

Improve the utilization efficiency of recycled water

Affected by natural factors such as terrain and climate, Turpan City of Xinjiang Uygur Autonomous Region has little precipitation and large evaporation, resulting in water shortage.

In the face of "water shortage", Turpan firmly established the water control concept of "water saving priority, spatial balance, and two hands", and promoted various works of water saving in a planned and step-by-step way, especially in the utilization of sewage. By the end of 2021, the centralized treatment rate of urban sewage has reached 100%, and the utilization rate of recycled water has reached 44.97%.

"At present, the sewage treatment system in the main urban area of our city has been formed, and the existing sewage network has 257 kilometers, covering more than 95% of the area." The person in charge of the relevant departments of Turpan City said that the treated sewage is mainly used for the greening of the factory area, the irrigation of the downstream ecological forest and the water source of Xinjiang Huadian Turpan Cold and thermal power plant.

For example, the person in charge said that at present, only the annual sewage treatment capacity of Gaochang sewage treatment plant can reach about 8 million cubic meters, and the amount of renewable water conservancy can reach about 3 million cubic meters.

According to reports, Gaochang District sewage treatment plant after several upgrades to improve the drainage network, improve the sewage treatment process, improve the effluent quality, improve the level of urban sewage treatment, Gaochang District suburbs all sewage to achieve centralized collection and treatment and discharge standards. At the same time, the odor generated in the sewage treatment process is collected and treated centrally, which effectively solves the environmental problems such as the perennial odor of the air around the sewage treatment plant.

Promote industrial water recycling

Promote the quality and efficiency of enterprises

Gaomi City of Shandong Province has more than 300 industrial enterprises above designated size, and industrial water consumption is large. As a city with relatively scarce water resources, Gaomi City has adhered to the concept of green development in recent years, encouraged industrial enterprises to use recycled water instead of tap water for industrial production, built a number of reclaimed water recycling projects, and the city's industrial enterprises have a water reuse rate of more than 80%.

Gaomi City Furi Water Purification Technology Co., Ltd. recycled water utilization project is one of them. The project has been constructed in two phases, with an investment of more than 100 million yuan in the first phase. The project was completed and started construction in May 2018, which mainly includes three parts: water intake pumping station, water transmission line and recycled water plant. The raw water is taken from the first sewage treatment plant, which adopts the treatment process of "high efficiency coagulation precipitation + ozone oxidation + carbon sand double-layer filtration + ultrafiltration + reverse osmosis" for in-depth treatment and recycling. It was put into operation in July 2019, with a daily treatment scale of 20,000 tons and a daily water reuse of 12,000 tons. The second phase of the project has an investment of 320 million yuan, a planned land area of 39.5 mu, the laying of 80.7 kilometers of water transmission and distribution pipeline, a daily treatment scale of 30,000 tons, and a daily reuse of 18,000 tons of water. After deep treatment, the tail water discharged from the second sewage treatment plant in Gaomi City will be supplied to enterprises such as chemical park, north industrial zone and high-tech zone. It can save more than 10 million tons of surface water for Gaomi City every year, and save more than 10 million yuan for the government's water transfer costs.

"The operation of the project has effectively improved the utilization rate of urban sewage, which can save more than 20 million yuan of sewage treatment costs for the government every year, and has good economic benefits and social value." The person in charge of the relevant departments in Gaomi City said.