For seawater desalination to be included in municipal drinking water, the state has issued several articles. Since the end of last year, the National Development and Reform Commission has issued the first special plan in the field of desalination, the “Twelfth Five-Year Plan for the Development of Desalination Industry”, this month. On the 17th, the State Council issued the "Twelfth Five-Year Plan for National Marine Economic Development" (hereinafter referred to as "Planning"), and once again proposed, "actively carry out seawater desalination projects into pilot projects for municipal drinking water projects, and encourage coastal cities and enterprises to Desalination water is used as production and domestic water."
It is understood that Qingdao has started the desalination project as early as 2006. At present, Qingdao Baifa Desalination Co., Ltd., which is responsible for the largest Sino-foreign joint venture desalination project in the country, has proposed to provide desalination water to urban residents in July last year.
However, on the 18th, the staff of the Qingdao Municipal Public Utilities Office revealed to reporters that the goal of seawater desalination being included in municipal water has not yet been achieved.
Why is this goal delayed? Is the capital investment insufficient? Is the price too high? Or is the technology immature? With these questions, the reporter conducted a visit.
Seawater introduction is pending
On the 18th, the reporter came to the west factory area of Qingdao Alkali Industry Co., Ltd., located at No. 2 Yinjiang Road, Lisong District, near Jiaozhou Bay, about 20 kilometers away from Qingdao Railway Station. The factory area was slightly deserted and entered the factory area. The blue signboard of “Qingdao First Municipal Desalination Project Department 300 meters to the right” led the reporter to find “Qingdao Baifa Desalination Co., Ltd.”.
It is understood that the Qingdao Baifa Desalination Project is jointly established by the Spanish Abengo Group and Qingdao City. The project uses the double membrane method reverse osmosis seawater desalination treatment technology. The construction and research of the project are all in the forefront of the country. It was completed and commissioned at the end of 2011 and officially opened at the end of July 2012. After the completion of the project, it was estimated that 100,000 tons of seawater could be desalted every day. These desalinated waters will directly enter the municipal water supply pipe network, which can meet the daily water consumption of 500,000 people.
The reporter saw at the scene that the plant equipment in the factory area was very new, but there was no sign of operation, and a group of skilled workers were packaged and left the factory. According to reports, the factory area is still not in use.
The reporter noted that Qingdao Baifa is a joint venture between Baifeisa Company and Qingdao Hairun Water Supply Group Co., Ltd. and Qingdao Alkali Industry Co., Ltd. The reporter tried to contact Qingdao Municipal Public Utilities Bureau, Qingdao Alkali Industry, Hairun Water Supply, etc., and did not receive a response.
Local people in Qingdao who are familiar with the situation disclosed to reporters that the unsuccessful progress of the project is also related to the inappropriate choice of the place originally selected. It is understood that the total design scale of 100,000 cubic meters / day, the daily sea water should be 200,000 cubic meters, such a large introduction of sea water scale, must rely on the power plant. Although it was later planned to introduce seawater using pipelines, it was not ideal, so the project has been solving the problems.
Unreasonable price system
Although the Baifa desalination project has not yet been put into use, the desalination of seawater into municipal drinking water has triggered hot discussion in the island city.
Wang Yuan, a native of Qingdao who lives in Chengde Road, told reporters that she is worried about whether the water quality after desalination is suitable for drinking and whether it will harm the health of the body. Wang Xiuliang, a taxi driver who lives in Lisong District, said broadly that as long as others dare to drink, he has nothing to fear, but he is worried that the price will be high, causing him to drink but not to drink.
“Seawater desalination and drinking water, there is a large degree of public acceptance, but the fundamental problem is price.” On the 18th, Wang Haizeng, deputy dean of the College of Chemistry and Chemical Engineering of China Ocean University and professor of marine chemical engineering and technology, was interviewed by the reporter. Said. He believes that the current price system for seawater desalination is unreasonable, and the new price system should be rationalized and formulated. The current seawater desalination price is 4 yuan - 5 yuan / ton. From the chemical professional point of view, the recommended price of Wang Haizeng is 2 yuan. /Ton.
It is understood that the price structure of tap water is very complicated, consisting of tax-included basic water price, sewage treatment fee, water resource fee, pipe network cost, water conservancy project fee, etc., but all have government subsidies.
Regarding the current situation that there is no government subsidy for seawater desalination and a large price difference with tap water, Wang Haizeng proposed that the government should provide certain compensation for desalination. According to his calculation of seawater desalination price, it should include saving fresh water cost and saving land cost. In his view, tap water needs to occupy a large reservoir for land occupation. The state finance allocates funds, and desalination saves land costs, so it should be compensated.
Regarding a series of problems such as whether water prices will be adjusted in the future and how to connect to drinking water, Qingdao Municipal Public Utilities Bureau said that this must be resolved through hearings and arguments.
According to industry analysts, energy costs account for more than half of all costs of seawater desalination, so professionals suggest that seawater desalination is only feasible when combined with cogeneration.
Industrial water should be used first
Wang Haizeng proposed that the three enterprises of Qingdao Power Plant, Huangdao Power Plant and Qingdao Alkali Industry are representatives of Qingdao's desalination application to industrial water seeking a circular economy. He has always insisted that seawater desalination should not be supplied with domestic water first, and industrial water should be supplied first. Industrial water supply can save industrial fresh water, which indirectly guarantees the supply of domestic water.
On the 18th, in Huadian Qingdao Power Generation Co., Ltd., Liu Naihua, a staff member of the Ministry of Political and Political Affairs, took a reporter to visit the desalinated plant area. After passing through the sedimentation tank that the sea water must pass, the reporter and his team came to the water purification workshop. Du Fanghua, a professional engineer, said that the company has started desalination since 2007. Each unit saves 120 tons of water per hour. Currently, two sets of equipment are in use.
It is understood that the power plant adopts the double membrane method reverse osmosis seawater desalination treatment technology, which is used for boiler steam power generation by desalination treatment of seawater.
“The two sets of equipment in the summer can provide about half of the water consumption for the entire power plant. In winter, because both power generation and heat supply are required, a large amount of tap water supply is needed.” Du Fanghua said, “The company has reserved equipment for the third phase of the project. In the outbound area, if 3 sets of equipment are operated at the same time, it is expected to save about 8856 tons of fresh water per day."
Du Fanghua believes that although the cost of purchasing tap water power generation is low, seawater desalination is an inevitable trend. If industrial electricity is implemented in the future, the advantages of seawater desalination will appear, and saving fresh water is also the social responsibility of enterprises.
Although some seawater desalination equipment, such as pumps, still need to be imported, Du Fanghua and Wang Haizeng agree that there is no obstacle to seawater desalination technology and grid connection with drinking water pipelines, mainly because of cost, because the salt content of seawater is more High, the pump's power consumption is greater, and the average company can't afford it.
Living water is harmless
Du Fanghua said that although the company specializes in industrial water use, it will not consider the problem of municipal drinking water. However, it is feasible to introduce domestic water into seawater desalination. It may lack nutrients. Some trace elements need to be adjusted, but it will never harm human health. .
According to industry insiders, the follow-up treatment of desalinated seawater drinking mainly includes adding carbon dioxide, calcium hydroxide and sodium hypochlorite, adjusting the pH value, increasing the hardness of water, enhancing the stability of water and drinking comfort, and simultaneously disinfecting the water to prevent it. Microbial contamination in the distribution network.
"Drinking desalinated seawater is a new thing in China, but it has been widely used in many countries. The United States, Australia, Singapore and other countries are carrying out seawater desalination. This technology has matured." Wang Haizeng said.
The "Planning" also emphasizes that in the coastal areas around power, chemical, petrochemical and other key industries, vigorously promote the direct use of seawater as industrial water, combined with water-saving renovation and new construction projects in coastal high-water consumption industries, and vigorously promote the application of seawater circulation cooling. Promote seawater as a large living water in conditional coastal cities.
It is reported that in November last year, the Jiaonan Island seawater desalination project in Jiaonan was officially completed and passed the acceptance test. The Lingshan Island desalination project has a total investment of 4 million yuan, covering an area of 1,53.85 square meters, and the designed water production scale is 300 tons per day. The project adopts reverse osmosis technology, and the seawater desalination is carried out by submersible pump taking seawater, self-cleaning filter and reverse osmosis device. The pH value of the diluted water is about 7 and has the characteristics of low salt content and comfortable taste. After the project is completed, it will provide production and living water for nearly 3,000 officers and soldiers stationed on the island of Lingshan Island.
Wang Haizeng introduced that at the end of last year, the Shandong Provincial Development and Reform Commission started the planning project related to the desalination industry and is currently studying it. He suggested that the state should invest water resources as a kind of food in the market and consider it as an important aspect of municipal construction.