2. Industrial equipment is corroded and the production capacity is reduced. After industrial water pollution, more control costs must be invested, resulting in a lot of waste of human and financial resources. The food industry has stricter water requirements, and the production will be stopped if the water quality is unqualified. This is also the main factor of low efficiency and poor quality of industrial enterprises. The use of sewage in agriculture will reduce crop yield and quality, even harm people and animals, pollute large areas of farmland and reduce soil quality. The consequences of marine pollution are also very serious, such as oil pollution, which causes the death of seabirds and marine life.
3. Destroy the ecological environment. The discharge of human domestic sewage leads to eutrophication of water body, the wild growth of plants such as algae in water, the decline of dissolved oxygen in water and even the emergence of anaerobic layer. It causes a large number of aquatic animals and plants to die, and the water stinks to form a "dead lake", "dead river" and "dead sea", which in turn becomes a swamp. This kind of water is smelly, dark in color and full of bacteria. The water quality is poor, so it cannot be used directly.