Comparison of textile printing and dyeing wastewater treatment processes

1 question raised

According to the "three simultaneous" principle, a sewage treatment station for treating printing and dyeing wastewater is installed. The core equipment is aerobic biochemical (activated sludge) SBR. The process is shown in Figure 1.



From the post-production practice, the treatment can meet the standard (cod <=110mg/1) under the conditions of suitable microbial ecological environment and frequent injection of more powdered activated carbon.



2 The necessity of anaerobic hydrolysis of organic wastewater

In the continuous operation of the organic wastewater biochemical treatment device, the hydrolysis reflector has been successfully installed before the aerobic biochemistry, and the effect is as follows:

(1) Anaerobic biochemistry can liquefy the organic suspension, so that the hydrolysis tank acts as a sinking tank for precipitating organic solids. (2) It can convert complex organic matter into simple organic matter and improve the efficiency of aerobic biological treatment. (3) Anaerobic hydrolysis can digest the remaining activated sludge of the aerobic biochemical device, and the amount of excess sludge itself is also small. Even if the sludge balance is not achieved, the activated sludge can be hygienic and harmless after anaerobic treatment, and the sludge treatment amount can be reduced, so that the sludge is more easily dehydrated. (4) The anaerobic biochemical process does not exist in the solution and diffusion of oxygen, and can be adapted to the treatment of high-concentration organic wastewater. After the anaerobic decomposition of the wastewater, the water can be reduced or not diluted before being transferred to the aerobic biochemical device. At the same time, the aeration power consumption is saved. (5) The need for anaerobic microorganisms nitrogen and phosphorus is much less than that of activated sludge. Obviously, the above-mentioned organic wastewater has the same advantages of hydrolysis and acidification before aerobic biochemistry, and is also applicable to SBR technology. Thanks to the following three characteristics, the effect will be better. (1) Since the excess sludge of the activated sludge SBR method is less than that of the general activated sludge process, the entire activated system can be greatly simplified by digesting the remaining activated sludge through the hydrolysis I tank.

(2) Since the hydrolysis tank is operated by the SBR method, the long-aged anaerobic sludge is easily retained, and the hydrolysis efficiency is improved.

(3) Adjust the residence time of anaerobic water SBR and optimize the technical and economic effects of the whole anaerobic hydrolysis-aerobic biochemical system.

3 The design of the hydrolysis tank is adapted to the local conditions

Due to the limitations of funds and sites, when the activated sludge SBR system is changed to hydrolyze aerobic biochemical SBR system, the sludge concentration tank can only be changed to the hydrolysis tank according to local conditions. The benefits are as follows:

(1) There are a large number of anaerobic sludge evolved from the remaining activated sludge in the pool, which is long in mud and quick to start.

(2) There is aerobic biochemical SBR residual sludge drain pipe to facilitate the treatment of residual activated sludge.

(3) The pool is an underground reinforced concrete structure, which is easy to keep warm.

(4) The pool has a partition wall divided into two sizes, and a submersible pump can be placed in the small pool for use as a dosing tank.

According to the above conditions, as long as the liquid distribution pipe is added to the bottom of the main tank where the original sludge is reduced, and the circulation pump constitutes a liquid system, circulation and agitation can be carried out, and then the pool cover and the supernatant (after sedimentation of the sludge) are self-set. The suction pump constitutes a simple anaerobic hydrolysis tank.

The hydrolysis-aerobic biochemical treatment system is shown in Figure 2. The equipment and process have been significantly simplified from the process comparison before and after the transformation.





4 hydrolysis aerobic biochemical SBR operation method

The cycle of anaerobic hydrolysis of SBR is the same as that of aerobic biochemical SBR. It is also divided into five stages: influent, reaction (continuous or intermittent circulation agitation), standing, drainage, and preparation. The specific operation method and working condition parameters are omitted.



5 Effects after the transformation