The cost is too high, the target of the 12th Five-Year Plan for the disposal of municipal sludge is in vain

Time: 2013-11-25 Source: China Economic Herald Author: snow

 

The “12th Five-Year Plan for the Construction of Urban Wastewater Treatment and Recycling Facilities” proposes that by 2015, the treatment rate of sludge in the municipalities, provincial capitals and cities with separate plans will reach 80%, and other cities will reach 70%. %, county towns and key towns reach 30%. According to several authoritative reports, nearly 80% of the sludge in China has not been effectively disposed of, and the problem of sludge treatment and disposal is not optimistic. Recently, experts interviewed by the China Economic Herald reporter bluntly said that due to the high cost, the “Twelfth Five-Year Plan” sludge disposal target is difficult to complete.

 

Sludge treatment and disposal

 

The State Council's "Opinions on Strengthening Urban Infrastructure Construction" proposes that by 2015, the rate of harmless disposal of municipal sludge should reach 70%. Hou Yuxuan, a researcher in the environmental protection industry of China Investment Consulting, said in an interview with the China Economic Herald that the sludge production in China is increasing every year. Although the sludge disposal capacity is also increasing, it faces technical choices and engineering implementation in sludge treatment and disposal. The problem, the progress is slow, and can not meet the digestion needs of the sludge. "From the reality, 70% of the goals are impossible to complete." Xu Haiyun, chief of the China Urban Construction Research Institute and secretary general of the China Municipal Environmental Protection Industry Association Urban Waste Treatment Committee, said in an interview with the China Economic Herald.

 

Sludge is an auxiliary product after sewage treatment. It is an extremely complex heterogeneous body composed of organic residues, bacterial cells, inorganic particles and colloids. At present, the sewage treatment rate has increased year by year, and the amount of sludge generated has increased rapidly, but the treatment and disposal of sludge has not been properly solved. The road of sludge treatment and disposal in China has gone very rough. The reason is that Xu Haiyun said in an interview with the China Economic Herald reporter that "the bumpy road is the normal performance of development. In recent years, it has been in the state of 'heavy sewage, light sludge', and the treatment and disposal of sludge has been neglected for a long time. The technical route of mud treatment and disposal is not clear. China's sludge disposal regulations clearly indicate 'adapted to local conditions'. In fact, sludge treatment and disposal is still in the exploratory stage."

 

In addition, Xu Haiyun believes that the division of responsibility of sludge treatment and sewage treatment plants is not clear, which is also the reason for restricting the development of sludge treatment and disposal. More often, sewage treatment plants do not regard sludge treatment as their responsibility.

 

The current sludge treatment method needs to be improved.

 

The insiders pointed out that there are many mainstream technologies for sludge treatment and disposal. In general, the technical route of sludge treatment is clear, the standards and specifications are basically sound, and the process and equipment parameters are also available.

 

In the specific technical process route selection, experts believe that the technical process route should be tailored according to the treatment and disposal targets. According to the treatment process, according to the amount of sludge generated, the nature of the sludge, combined with the natural environment and disposal conditions, the actual sludge treatment process is selected. Liang Yimin, technical director of AECOM Asia, a US consulting firm providing technical and management services, believes that no technical route is suitable for all cities. It is necessary to evaluate the actual situation and understand the advantages and limitations of each technical route.

 

The relevant person in charge of the China Industrial Energy Conservation and Cleaner Production Association said that the current practice of sludge treatment is that the sewage plant dewaters the sludge to about 80% of the water content, and the sludge bids farewell to the sewage plant. Because the water content is too high, the composition is complicated, and the professional level of resource utilization is low, most of the sludge in the country has not been stabilized and disposed of in a harmless manner. Most of the sludge is sent to the municipal waste treatment plant for simple landfill, even in Simple stacking in the open air.

 

Incineration and landfill disposal methods are inefficient and environmentally damaging, while the digestive technology commonly used in developed countries is not widely used in China. Hou Yuxuan said: "In particular, there is still a serious problem in China. For example, there are more than 50 sludge digestion facilities in big cities such as Beijing and Shanghai, but only a dozen or so are in operation." Hou Yuxuan explained this phenomenon. In the sludge digestion process, due to lack of practical experience, insufficient policy support, and lack of operation methods, the processing efficiency is not high and the operating costs are increased. In order to avoid the increase in losses, several sludge digestion facilities have ceased to operate.

 

He believes that "it is necessary to gradually ban landfills and reduce incineration, and popularize digestive treatment technology to achieve the technical route of sludge reduction and stabilization."

 

Jiang Jianguo, deputy dean of the School of Environment at Tsinghua University, holds the same view. Jiang Jianguo said that landfill is not the best way to deal with it. The landfill has certain difficulties in site selection and construction. Due to the entry of organic matter, the pollution of the landfill itself is more serious. Problems such as site selection and storage capacity are also difficult to solve.

 

“Sludge incineration is not a bad thing, but there are many problems. I think incineration is a helpless choice. Before the establishment of a standardized sludge agricultural technology system and management system, incineration is an important means to temporarily solve the sludge problem.” Wang Hongchen, deputy dean of the School of Environment of Renmin University of China, said that agricultural utilization is a high-level way of sludge treatment and disposal. On the basis of strict treatment, through scientific evaluation, tracking and supervision, it is possible to realize the use of resources, control risks, and benefit.

 

Harmless treatment cost is the key

 

“To better realize the harmless treatment and disposal of sludge requires relatively high capital investment. Historically, there has not been much consideration of the cost of sludge treatment, so some sludge disposal facilities are relatively weak, and if the proportion of harmless treatment is increased, More relevant facilities investment and more facilities operating costs are needed.” Jiang Jianguo said, “There are some problems in the process of sludge treatment and disposal, but it is not a fundamental problem. The technology is still relatively mature. The fundamental problem lies in the construction. Cost and operating costs."

 

“The government can reduce barriers to entry and introduce private capital and social funds,” said Hou Yuxuan. As early as November 2011, the “Notice on Adjusting and Perfecting the Comprehensive Utilization of Resources and Labor Value-added Tax Policies” issued by the State Administration of Taxation of China, the sludge treatment was included in the scope of exemption from VAT, resulting from the use of sludge fermentation. The power and heat value-added tax for biogas production is 100%, and the policy will greatly improve the enthusiasm of sewage treatment enterprises to dispose of sludge, thus promoting the sludge harmless treatment into a rapid development period.

 

In addition to the capital taxation, Hou Yuxuan also suggested that in order to solve the problem of sludge treatment and disposal in China, the provinces should first formulate sludge disposal plans for site selection for sludge treatment plants. Second, plan the sewage treatment plant and sludge disposal at the same place. To reduce unnecessary links and improve efficiency; finally, improve sludge digestion capacity, including research and development of new technologies and system linkages.

 

Tang Jianguo, deputy director of the Water Resources Department of the Shanghai Water Affairs Bureau and professor-level senior engineer, summed up the two principles followed by sludge treatment and disposal: First, disposal decisions, treatment to meet disposal, various treatment methods, and appropriate intensive treatment. Second, the determination of sludge treatment process should reflect the following four points: "Based on volume reduction treatment, with stabilization as the core, resource utilization as the goal, and the overall impact on the environment as the minimum." He hoped that the sludge treatment enterprises would combine the local conditions and take practical measures according to the principle of sludge treatment and disposal.