Method for treating papermaking wastewater by nano chitosan composition flocculation system

Abstract

The invention belongs to treatment and comprehensive utilization of three wastes and relates to a method for treating papermaking wastewater by adopting a nano chitosan composition flocculation system. Currently, most of flocculating agents for treating the papermaking wastewater are polymeric aluminum salts and cation polyacrylamide, the polymeric aluminum salts and the cation polyacrylamide have insufficient flocculation capability for pollution sources in the wastewater, and precipitates have defects of coarse particles, loosening and the like. Nano chitosan sol has a three-dimensional network conformation and has excellent flocculation characteristic. Compared with a composition of the polymeric aluminum salts and the cation polyacrylamide, the nano chitosan composition flocculation system has the advantages that the relative flocculation rate (percent) for the pollution resources in the wastewater is improved by 40 percent; in treated supernatant water, an SS (Suspended Solid) value is similar and a CODcr (Chemical Oxygen Demand) value and a BOD5 (Biochemical Oxygen Demand) value are reduced by 8 to 12 percent; and the treatment cost is only 26 percent of the treatment cost of the composition of the polymeric aluminum salts and the cation polyacrylamide. By microscopic observation, adsorption points are formed by flocculate in a fiber and chitosan sol network, fine particles are precipitated and the precipitation is compact. The nano chitosan composition flocculation system is a pure natural flocculation material with both high activity and biodegradability.

Description

[0001] Technical field: the invention belongs to the treatment and comprehensive utilization of three wastes. The method adopts a nano-chitosan combined flocculation system to treat papermaking wastewater. Background technique:

[0002] Papermaking is needed for the survival and development of human beings, and the huge amount of waste water discharged by the papermaking industry has caused huge socio-economic and environmental ecological pressures on the sustainable development of human society.

[0003] A large amount of wastewater discharged by the paper industry contains a large amount of cellulose, lignin and chemicals, which consume a lot of oxygen, and are the most concerned pollution sources, especially cooking waste liquid, which has the most serious environmental pollution. There are many impurities in papermaking wastewater, and the particle size distribution is uneven. Some are in a colloidal state, and some are suspended in water. It is difficult to meet the requi...