Composite reagent for treating recycled water of printing and dyeing wastewater and application method of composite reagent

Abstract

The invention discloses a composite reagent for treating recycled water of printing and dyeing wastewater and an application method of the composite reagent. The composite reagent comprises the following components by weight percent: 20% to 70% of aluminum salt coagulant, 5% to 30% of iron salt coagulant, 5% to 40% of mineral material and 5% to 45% of activated carbon. The method comprises the following steps: preparing the composite reagent for treating the recycled water of the printing and dyeing wastewater into powder or an aqueous liquid in which the content of effective components accounts for 5% to 30%; regulating a pH value of effluent in a printing and dyeing wastewater biochemical system to be within 3 to 9; adding the powder or the aqueous liquid of the composite reagent into the effluent in the printing and dyeing wastewater biochemical system under the condition that the adding quantity of the effective components is between 20mg/L and 1000mg/L after the pH value of the effluent is regulated; and stirring for 0.2 to 2 hours and then standing so as to obtain the recycled water conforming to the water quality standard in textile industry. According to the method, macromolecular colloidal pollutants in the biochemical effluent of the printing and dyeing wastewater, which are difficult to degrade, can be removed by utilizing the coagulation/flocculation performance of aluminum salts and iron salts in the composite reagent; and meanwhile, soluble inert pollutants in the wastewater are removed by utilizing the adsorbability of the activated carbon and the mineral material in the composite reagent.

Description

technical field [0001] The invention belongs to the technical field of printing and dyeing wastewater reuse in environmental protection, and in particular relates to a compound agent for treating printing and dyeing wastewater reused water and an application method thereof. Background technique [0002] At present, China's textile printing and dyeing industry is still an energy-intensive industry in general, and the amount of wastewater generated per 100 meters of cloth in the dyeing and finishing of woven fabrics is 1.6 to 2.4 tons. The wastewater discharge of the textile dyeing and finishing industry accounts for 7.5% of the national industrial wastewater statistical discharge. , about 1.13 billion tons per year, while the wastewater reuse rate is less than 10%. In response to the above problems, the "Twelfth Five-Year Development Plan of the Textile Industry" requires the textile dyeing and finishing industry to strengthen energy conservation, emission reduction and reso...

AI Technical Summary

Problems solved by technology

For new projects, the COD and chromaticity limits for direct wastewater discharge are as low as 80 mg / L and 50 times, and the COD limits for existing projects are only 100 mg / L and 70 times

In addition, some provinces with developed printing and dyeing industries, such as Zhejiang Province, require the average reuse rate of printing and dyeing industry to be no less than 35%, of which non-cotton projects should not be less than 50%, which poses new challenges to the recycling of printing and dyeing wastewater

[0004] Printing and dyeing wastewater is mainly treated by combined biochemical and physical chemical treatment methods. However, although the chromaticity, COD and other indicators of the wastewater treated by traditional processes may meet the discharge standards, as reused process water, the water quality indicators, especially organic matter, There are more stringent requirements for indicators such as chroma and hardness, and it is difficult to meet the water quality standards for textile printing and dyeing processes

At present, the printing and dyeing wastewater reuse technology usually adopts the membrane treatment method, but the high investment and operation costs are still the bottleneck of its wide application