Recovery and treatment process of boiler wastewater based on ion exchange and chemical precipitation

Abstract

The invention relates to a boiler blowdown water recycling treatment technology based on ion exchange and chemical precipitation. The technology comprises the following steps that boiler blowdown water is filtered by an efficient fiber filter, so that the turbidity of the filtered and purified blowdown water is decreased to be smaller than 1 NTU, and an SDI value of the filtered and purified blowdown water is smaller than 3; the filtered and purified blowdown water is delivered to an ion exchanger, effluent water exchanged by anion exchange resin enters a boiler raw water tank, and after the anion exchange resin is saturated, regenerating is conducted by adopting a regenerating agent, so that an exchange function of the anion exchange resin is recovered; coagulation treatment and flocculent precipitation treatment are conducted on regenerated waste liquid and backwashing waste liquid of the ion exchanger by adopting a coagulant and a flocculant. Compared with the prior art, the high-concentration waste liquid or regenerated liquid achieves solid-liquid separation by adding a small quantity of the coagulant and a coagulant aid through the coagulation effect and the flocculent precipitation effect while high-quality recycling on the boiler blowdown water is achieved through ion exchange, removal of phosphate in the boiler blowdown water is completed, and zero discharge of the boiler blowdown water is achieved.

Description

technical field [0001] The invention relates to a recovery and treatment process for boiler sewage, in particular to a recovery and treatment process for boiler sewage based on ion exchange and chemical precipitation, and belongs to the technical field of water pollution control. Background technique [0002] With the rapid development of industry and agriculture and the rapid expansion of urbanization, the shortage of water resources in my country has become more and more prominent. To solve the problem of water shortage, it is far from enough to rely solely on opening up new water sources, and the cost of water intake is gradually increasing. The difficulty is also increasing. At the same time, the utilization of water resources in my country is quite extensive at this stage. With the promulgation of new water-saving and energy-saving policies, we are objectively required to use the concept of circular economy to think about the control of industrial water pollution and imp...

AI Technical Summary

Problems solved by technology

In the process of removing phosphorus by calcium salt chemical precipitation, the pH of wastewater has a great influence on the removal effect of phosphorus precipitation. The higher the pH value, the better the effect of phosphorus removal. When the pH value of wastewater is 8.0, calcium carbonate CaCO 3 The formation of calcium hydroxyphosphate will obviously inhibit the formation of calcium hydroxyphosphate precipitate, and the phosphorus removal effect is poor, and when the pH value is 9.0, this inhibitory effect will be weakened

Therefore, in order to maintain a high removal rate of phosphorus in the effluent, it is usually necessary to add a large amount of lime to adjust the pH value of the wastewater to a higher value (10.0-11.0), which leads to a large consumption of chemicals and higher costs. The amount of mud has increased greatly, so the method of adding calcium salt is generally less used for chemical precipitation to remove phosphorus

[0009] Combining the above various chemical precipitation methods, they all show a certain degree of treatment effect in terms of targeted removal of phosphate. However, due to the many control conditions of the chemical precipitation method, it is affected by pH, temperature, and the type, ratio, and concentration of the chemical agent. The constraints of other factors are obvious, so the effluent water quality is also difficult to control, especially for the treatment of a large amount of low-concentration phosphate sewage in the boiler system, the chemical precipitation method alone not only greatly affects the reuse quality of the treated effluent, but also A large amount of chemical sludge will be generated, which will increase the cost of subsequent treatment

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