A clean production method for increasing the recovery rate of excess activated sludge nitrogen and phosphorus

Abstract

The invention provides a cleaner production method for increasing the nitrogen and phosphorus recovery rate of residual activated sludge. The method includes the steps that 1, the sludge is pressed and filtered till the water content of the sludge ranges from 75% to 80%; 2, the pressed sludge is mixed with water again according to the ratio of 1 g / 3-5 ml and immersed in water for 2 h; 3, mixed liquor is stirred and aerated, and the stirred and aerated mixed liquor is naturally settled after 12 h to 72 h; 4, supernate obtained after natural settling is drained to an MAP precipitation reactor, the P / Mg / N molar ratio is adjusted to be 1 / 1.2 / 1 by adding a magnesium salt solution and a phosphor salt solution, the pH value of the reaction solution is adjusted to be 8.9+ / -0.1 through 5MNaOH, and nitrogen and phosphorus in the supernate generates the MAP precipitation reaction; 5, sediment generated in the step 4 is discharged to a separation recovery device to be recovered and settled, the settled supernate is mixed with bottom mud in the step 3 again, and after the pH value of the bottom mud is adjusted to be 8.0-8.5 through alkali in the supernate, the bottom mud is discharged to a mechanical dehydration device, pressed and then discharged. Operation is convenient and easy to implement, no new chemical matter is introduced, following sludge anaerobic digestion treatment is facilitated, and the recovery cost of nitrogen and phosphorus resources is low.

Description

technical field [0001] The invention relates to a clean production method for improving the recovery rate of excess activated sludge nitrogen and phosphorus, and realizes the goal of efficient utilization of excess activated sludge nitrogen and phosphorus resources in sewage treatment plants, belongs to the technical field of sludge sewage treatment and resource utilization, and is a clean production method new technology. Background technique [0002] There are more than 400 sewage treatment plants across the country, with a sewage treatment capacity of more than 10 billion cubic meters. About 86.2% of the sewage treatment plants use the activated sludge method. 0.3%~0.5%, so that the amount of excess sludge generated reaches 150×10 4 t / a, and increase by 10% year by year. The cost of treatment and disposal accounts for 25% to 40% of the total operating cost of the sewage treatment plant. The treatment and disposal of sludge from urban sewage plants has become a major en...

AI Technical Summary

Problems solved by technology

[0006] Aiming at the problem of nitrogen and phosphorus release in the reuse of excess activated sludge in sewage treatment plants, the present invention provides a clean production method for efficient and rapid release of nitrogen and phosphorus from excess activated sludge in sewage treatment plants and resource utilization