However, the artificial discharge of nitrogen (mainly ammonium salt, nitrate and nitrite) and phosphorus (mainly orthophosphate and various forms of phosphate) into the water body makes the fresh water eutrophic, which exceeds the environmental capacity and self-purification ability. Bloom? Frequent occurrence, the area spread year by year, and the duration extended year by year. There are water blooms in Taihu Lake, Dianchi Lake, Chaohu Lake and Hongze Lake in China.
Water bloom has become a worldwide public hazard. Water bloom frequently occurs in more than 30 countries and regions such as the United States, Japan, China, Canada, France, Sweden, Norway, the Philippines, India, Indonesia, Malaysia, South Korea and Hong Kong.
Treatment of water bloom
(1) Use physical methods:
Fishing filamentous algae and other floating objects in the water. If conditions permit, algae can be removed by circulating filtration.
(2) Using chemical methods: (Frequent use will easily lead to the accumulation of chemical substances and cause secondary pollution; Phytoplankton such as algae produce tolerance, microbial variation and other consequences)
Use chemical agents, such as copper sulfate, quaternary ammonium salt, activator, potassium permanganate, polyaluminum chloride, ferrous sulfate, etc. Killing, flocculating and precipitating excess plankton and algae can quickly improve the water quality and see the effect.
However, these effects are only temporary and partial. Because the degraded nutrient source has not been fundamentally eliminated, the original benthic organisms in water have strong anti-pollution and anti-killing ability. Once the concentration of these chemicals is reduced and the reaction effect is weakened, these lower organisms will grow rapidly and return to their original state.
More importantly, frequent and long-term use of these chemicals will lead to the accumulation of chemicals, water poisoning and secondary pollution, so use them with caution.
(3) adopting a composite method:
The clay containing microbial inoculants is used to adsorb algae in water, and then the clay wrapped with algae is flocculated and settled by flocculant, which blocks the light condition of algae growth, achieves the purpose of gathering algae from water in a state of uniform distribution and separating them from water, and increases the transparency of water. The above methods can obviously improve the sensory indexes of water body: improve transparency, reduce odor, reduce odor; Can reduce water pollution indicators: reduce DOD, ammonia nitrogen and so on.
(4) adopting a microbial method:
① Aeration and reoxygenation: It is a basic measure to aerate and reoxygenate water by equipment or other means. Its function is various.
(2) Under the condition that the water quality does not reach a certain healthy level, a certain number of artificial aquatic plants can be arranged at this stage, imitating the membrane hanging technology in sewage treatment, so as to create artificial conditions for the colonization, growth and function of microorganisms. (Suspended growth bacteria and attached growth bacteria)
③ Putting microbial agents: According to the results of the water quality analysis report, analyze the contents of major water quality indicators such as COD, ammonia nitrogen, total phosphorus and nitrite, and their content ratios, and put microbial agents in stages to deal with them.
Its main components are compound Bacillus, yeast, phosphorus accumulating bacteria, digestive bacteria and anti-digestive bacteria. Of course, the same strain is divided into different strains, and its functions and functions are different. Achieve the effect of nitrogen and phosphorus removal, gradually digest and reduce the content of water, and balance and stabilize the content and proportion of these elements in water.
Adding microbial agents has two main functions. One is to activate indigenous microorganisms in the original water body and sediment, including anaerobic bacteria, facultative bacteria and aerobic bacteria, and decompose the organic matter in the water body into simple organic molecules and inorganic molecules, and then decompose them into monomer molecules to enter the circulation chain of the ecosystem. Anaerobic bacteria and facultative bacteria eventually decompose organic matter in water into methane, hydrogen sulfide, carbon dioxide and so on. Aerobic bacteria eventually decompose organic matter in water into simple nitrogen, carbon dioxide and water.
Secondly, by adding microbial strains, some key microorganisms and nutrients lacking in water species are supplemented, and gradually domesticated, proliferated, subcultured and propagated, a relatively balanced and complete dominant flora suitable for the specific ecological environment of water body is formed, so as to achieve bacterial phase balance and algae phase balance, and cooperatively decompose harmful organic substances in water body.
(5) adopting the method of biotechnology (establishing artificial ecosystem):
The above four methods and means are not enough to restore and maintain the self-purification ability of water bodies. In order to make the water into a better state, biological treatment must be carried out next. Gradually establish an artificial ecosystem.
① Planting aquatic plants: select aquatic plants and ornamental plants suitable for local water bodies, including submerged plants, emergent plants, floating plants and ornamental plants. The function of aquatic plants is all-round, which cannot be replaced by other means.
② Adding proper amount of fish and shrimp fry: Fish and shrimp are the most typical consumers in the biological chain, and they can convert carbohydrates, primary protein and fat in plant state into advanced protein and fat. Herbivorous fish, such as grass carp. Omnivorous fish, such as crucian carp and flat fish; Carnivorous fish, such as Qing Wu, snakehead and mandarin fish; Others specialize in plankton, such as silver carp and bighead carp. When stocking fish and shrimp, we should pay attention to the collocation between herbivorousness, omnivorousness and carnivorousness. The stocking quantity should be adapted to the water area; We must also control the growth and reproduction of fish and shrimp. Raising fish and shrimp in water can consume carbohydrates, primary protein and fat in water, and control the density of plants and plankton in water to some extent. At the same time, it can also provide food for the same kind. Fish and shrimp swim freely in the water, which increases the ornamental effect of water features.
(3) Add a proper amount of snails, mussels and other shellfish: snails, mussels and a large number of benthic organisms form another world at the bottom of the water, which not only complement each other, but also consume a lot of leaves, residues, corpses and excreta. Some small invertebrates also have the function of decomposing organic matter. Their secretions are good bioflocculants, which can coagulate and precipitate organic and inorganic suspended substances in water and improve the transparency of water.
(4) Large water bodies can also be used to breed appropriate amount of waterfowl.
Form multiple food chains: green plants are eaten by herbivores, herbivores are eaten by carnivores, and the residues of plants and animals can be decomposed into small animals and lower animals, forming a food chain relationship. Organic pollutants are not only degraded and purified by bacteria and fungi, but also the final products of their degradation. Some inorganic compounds, as carbon sources, nitrogen sources and phosphorus sources, take solar energy as the initial energy source, participate in the metabolic process of food webs, gradually migrate and transform from low trophic level to high trophic level, and finally transform into aquatic crops, fish, shrimp, mussels and other products.
In this artificial ecosystem, there are not only decomposers, producers, but also consumers, who work together to treat and utilize pollutants in sewage more effectively, thus forming many food chains and criss-crossing food web ecosystems. A good ecological balance system can be established by maintaining appropriate quantity ratio and energy ratio between different trophic levels. So as to maintain the health and stability of the water body.
The existence of biological chain promotes simple inorganic substances in the ecological environment? Organic matter? Simple inorganic matter circulates repeatedly, forming what is usually called ecological balance.
⑤ Normalization and daily management.
Because the water bodies in cities are generally small, the environmental capacity and pollution capacity are also quite small, the established artificial ecosystem is quite fragile and easily affected by various factors, thus cutting off the biological chain and causing the whole ecosystem to be destroyed.
Daily and regular follow-up monitoring intervention mechanism should be established for the maintenance of water bodies. Through human efforts and scientific management, producers can maintain their lives in rivers, lakes and water bodies? Consumers? Restore the human biological chain, actively and continuously carry out necessary interventions to promote its balance. Harm of water bloom