The illegal disposal of sludge has become the focus of social attention and the focus of ecological and environmental protection inspectors. For example, the second round of ecological and environmental protection inspectors have found long-term illegal disposal of sludge in many places. The fourth batch of inspectors found that some enterprises in Suining, Sichuan had illegally disposed of sludge in the name of soil improvement for a long time. The Sixth Batch of inspectors found that some enterprises had illegally disposed of sludge in Xingtai, Tangshan and other places in Hebei Province. Sludge problem has become the bottleneck and weakness of ecological civilization construction and ecological environment protection in some places.

The author believes that the existence of this problem is mainly caused by three reasons.

First, the enterprise's "money saving" mentality. Most of the sewage treatment plants hand over the sludge to a third party for disposal, which requires corresponding disposal costs. It is understood that according to the different disposal methods, at present, a ton of sludge needs to be disposed of by paying a third party a disposal fee ranging from 100 yuan to several hundred yuan, which is a great burden for enterprises, leading to some enterprises to cut corners on work and materials and resort to fraud in sludge disposal.

Second, the disposal channels were narrowed. In the past, the sludge was mainly transported to the nearby landfill for sanitary landfill. However, with the improvement of the whole society's ecological environment awareness and the need of land conservation and intensive utilization, some places gradually restricted or even eliminated the disposal of sludge by sanitary landfill, which objectively narrowed the disposal channel.

Third, the illegal cost is low. In some places, the idea of "emphasizing water over mud" is serious, and the focus of work is on sewage treatment, while the sludge treatment is not paid enough attention and supervision is neglected. Even if the enterprise is found to have illegal and illegal disposal problems, it is often held high and handled lightly or even left unchecked, which encourages the illegal and illegal behavior of the enterprise.

Sludge is a by-product of sewage treatment, which contains a large number of toxic and harmful substances and pathogenic microorganisms, and also contains certain nutrients and rich organic matter. If it is not handled properly, all kinds of pollutants contained in it will return to the natural environment and affect the ecological environment. However, if properly handled, waste can be turned into treasure. In the long run, it is the general trend for sludge to take the road of resource utilization.

The author suggests that all localities can, in combination with the "waste free city" pilot project, increase the support in terms of policies, funds, technologies, etc. in the utilization of sludge resources, solve the problem of sludge resources utilization, and make the sludge change from a pollution source to a new resource.

Explore and implement diversified disposal paths. In the aspect of sludge resource utilization, some places have made beneficial exploration. For example, Yunnan Province has developed and applied the sludge pyrolysis and carbonization technology. The sludge is pyrolysis in an oxygen-free environment to generate pyrolysis oil gas and biochar. The pyrolysis oil gas is directly recycled to replace the external heat source. The generated biochar can be used for soil improvement, and can also be used to produce carbon based fertilizer and building materials. By using the new technology of high temperature fermentation, Chongqing can transform sludge into high nutrient fertilizer for landscaping.

The local government should implement the main responsibility of sludge disposal, make overall planning, take measures according to local conditions, actively learn from the experience and practices of region, and explore and implement the disposal mode that conforms to local conditions. Establish a diversified investment and operation mechanism, encourage and guide the participation of social capital through PPP and other modes, and help enterprises legally and reasonably solve the problem of sludge resource utilization.

We will increase policy support. Compared with traditional disposal methods such as sanitary landfill, the cost of new technologies such as sludge pyrolysis and carbonization and organic fertilizer production is higher. If all these costs are borne by enterprises, their enthusiasm may be affected. The local government shall give financial support to the sludge resource utilization project, and the sludge organic fertilizer meeting the standards can be listed in the government procurement catalogue. Meanwhile, the collection standard of sewage treatment fee shall be adjusted in time. The new solid waste law, which came into effect on September 1, 2020, clearly stipulates that the collection standard and compensation scope of sewage treatment fee shall cover the sludge treatment cost and the normal operation cost of sewage treatment facilities. However, it is understood that some localities have not adjusted the collection standard and compensation scope of sewage treatment fees. The local government shall make timely adjustment according to legal procedures to better meet the needs of sludge disposal.

We will severely crack down on violations of laws and regulations in sludge disposal. Strengthen the supervision and management of the utilization of sludge resources according to law, crack down on arbitrary dumping and illegal stockpiling, and guide enterprises to operate in accordance with the law and develop in a standardized manner, so as to achieve a win-win situation of ecological and environmental benefits and economic and social benefits.