1. The amount of sewage is large and the composition is complex.

A large amount of sewage produced by industrial production, agricultural irrigation and domestic water is not only huge, but also contains various harmful substances, such as heavy metal ions and organic pollutants, which greatly increase the difficulty of sewage treatment. For this problem, we can combine source control with terminal treatment, for example, by improving the utilization rate of water resources to reduce sewage discharge; At the same time, high-efficiency sewage treatment technology is developed, and different treatment methods are adopted for different types of pollutants to achieve precise treatment.

2. Inadequate or aging treatment facilities

Due to historical reasons, the construction of sewage treatment facilities in many areas is lagging behind or the equipment is aging, which cannot meet the current demand. In this regard, the government should increase investment, speed up the upgrading of old facilities, and introduce advanced sewage treatment technology and equipment. In addition, social capital should be encouraged and supported to participate in the construction and operation of sewage treatment projects, and a diversified investment and financing mechanism should be formed.

3. Imperfect regulations and standards

The lack of a unified standard system and strict laws and regulations has restricted the development of sewage treatment industry. Therefore, it is very important to establish and improve relevant laws and regulations. The state needs to introduce more scientific and reasonable water quality standards and emission requirements, and clarify the responsibilities and obligations of all parties; Strengthen the supervision of illegal sewage discharge to ensure the effective implementation of various regulations.

4. Weak public awareness

　　The public's understanding of environmental protection is not deep enough, and they lack the initiative to participate in environmental protection. Strengthening citizens' awareness of environmental protection is a long-term and arduous task. Various publicity and education activities can be carried out to popularize environmental protection knowledge, guide people to establish correct consumption concepts and lifestyles, and participate in water resources protection together.

In a word, facing the difficult problem of sewage treatment, we need to start from multiple angles, comprehensively use legal, economic and technical means, and constantly explore innovative solutions to contribute to the construction of beautiful China.