Wastewater and sewage treatment

Globally, due to rapid urbanization and economic development, the demand for fresh water has increased steadily, and the available natural resources are also being consumed, which has put increasing pressure on the existing reserves. Water is a valuable and increasingly scarce commodity. In order to meet the scarcity challenge, the world needs more sustainable and effective water and wastewater management practices and technologies.

In the biological treatment process of wastewater, microorganisms are used to collect suspended solids, dissolve organics and stabilize organics. In addition, biological treatment of wastewater can remove or stabilize nutrients such as nitrogen and phosphorus, which can stimulate the growth of aquatic plants. The survival and relative growth of various microorganisms depend on the environmental conditions existing in the liquid. The most important is the quantity of food and nutrients in the liquid, pH, temperature and oxygen availability.

Dissolved oxygen plays a very important role in water treatment. Some compounds in sewage are biodegradable under the action of aerobic bacteria, and dissolved oxygen in water is consumed. Dissolved oxygen should be kept at a certain concentration. During the aerobic treatment of buried domestic sewage treatment equipment, the dissolved oxygen in the air and the photosynthesis of green aquatic plants will continuously supplement the dissolved oxygen in the water. However, when the water body is polluted by organic matter, the oxygen consumption will greatly increase. If dissolved oxygen is not added in time, the anaerobic bacteria in the water body will rapidly multiply, and the organic matter will cause the water body to become black. However, the concentration of dissolved oxygen should be controlled, because if the concentration is too high, the oxygen transmission rate will be reduced, and the power cost of buried domestic sewage treatment equipment will increase, resulting in the oxidation of activated sludge and the non-flocculation of sludge, It affects the sedimentation effect of the floc.

Under natural conditions, the oxygen content in the air is not much, and the water temperature is the main factor. The lower the water temperature is, the higher the dissolved oxygen content in the water is. Molecular oxygen dissolved in water is usually called dissolved oxygen, expressed in milligrams per liter of water. The amount of dissolved oxygen in water is an indicator to measure the self-purification capacity of water body. The dissolved oxygen value is the basis for studying the self-cleaning ability of water. The average dissolved concentration should be kept at 2 mg/l, and the activated sludge can be kept in good and optimal condition.

By injecting oxygen into the sludge plant equipment, sludge sedimentation can be improved, sludge load reduced and purification capacity improved. These improvements have led to lower wastewater charges and odorless purification, and eliminated the dangers, costs and logistics problems of liquid oxygen transportation. The on-site pressure swing adsorption (PSA) oxygen generator of CSCEC Aerospace can ensure qualified oxygen supply to assist the whole process of water treatment system.