Biological Contact Oxidation Makes Printing And Dyeing Wastewater Treatment A New Step.

Aerobic treatment technology has been widely used in the treatment of municipal wastewater and industrial wastewater. The main form of treatment is activated sludge and biofilm. Biofilm has biological filters, biological rotary tables, biological contact oxidation and biological fluidized beds.

In our engineering design and actual operation for many years, according to the characteristics of printing and dyeing wastewater, such as high concentration of pollutants, high chromaticity, and large change in pH value, we have developed a biological contact oxidation process suitable for this kind of wastewater treatment and its own characteristics.

Biological contact oxidation process is a biofilm process between activated sludge and biofilter, which is characterized by setting up fillers in the tank, aerating the bottom of the tank to oxygenate the sewage, and making the sewage in the tank flow in order to ensure that the sewage is fully contacted with the filling material immersed in the sewage, so as to avoid the unequal contact between the sewage and the filler in the biological contact oxidation pond.

I. reaction mechanism of biological contact oxidation process

In the biological contact oxidation process, the oxygen required by microorganism is supplied by blowing aeration. After the biofilm grows to a certain thickness, the microorganism near the packing wall is anaerobically metabolize due to anoxia. The scour produced by the gas and aeration will cause the biofilm to fall off, and promote the growth of the new biofilm and form the metabolism of the biofilm. The biofilm falling off will flow out of the pool.

Biological contact oxidation has the following characteristics:

1, as a result of

The specific surface area is large, the oxygen condition in the tank is good, and the biomass of the unit volume is higher in the pool. Therefore, the biological contact oxidation tank has a higher volume load.

2. Due to the fact that there are many biological solids in the biological contact oxidation pond and the water flow is completely mixed, it has a strong adaptability to sudden changes in water quality and quantity.

3, the surplus sludge volume is small, there is no sludge expansion problem, operation and management is simple.

Two, design points

1. Filler selection

Packing is a kind of microbial carrier with larger specific surface area. Its characteristics play an important role in the biological solids, oxygen utilization, water flow conditions and the contact between wastewater and organisms in the contact oxidation pond.

Based on years of operation experience, our company takes into account

Properties, organic load and filler characteristics, after comparison, the final selection of combined fiber filler, operation is not easy to plug, light weight, low price, good treatment effect.

2, according to the characteristics of printing and dyeing wastewater, when designing biological contact oxidation tank, our company often designs the pre sedimentation tank in the middle and the back section of the pool. One is to reduce the SS concentration in the effluent and ensure the subsequent sedimentation tank treatment effect; two, the sludge returned to the anaerobic pond ensures that the sludge has certain sludge concentration and ensures a high removal rate.

3. Selection of high efficiency aeration and oxygen charging mode

1) selection of aerator

In wastewater treatment, aeration includes jet aeration, surface aerator and variable microporous tubular aeration.

In the operation of sewage treatment station, power consumption is the main body of operation cost, and the power consumption of aeration equipment is the main equipment for power consumption of the whole system.

Tubular variable microporous aerator is a new and efficient aeration equipment jointly developed by our company and our brother unit.

Variable microporous aerator is a kind of aeration equipment designed under negative pressure. It has the characteristics of microporous aeration, blockage prevention, effective service area, small bubble diameter and high oxygen utilization rate.

Its oxygen utilization rate is more than 20% (Tongji University environmental protection product quality supervision and inspection center in 4m depth, with water submergence test, oxygen utilization rate of 29%), and has been used in the long-term operation of the project, has achieved good aeration effect, the use of the aeration equipment, can reduce the power consumption of the fan, reduce the entire sewage treatment operation cost.

The membrane of variable microporous aerator uses high quality imported raw materials to ensure the service life.

2) selection of aeration device configuration

Conventional

The aeration mode is to install perforated pipes or aeration discs at the bottom of the pool. The main drawback is that the oxygen utilization rate is not high, the power consumption is large, and the maintenance and maintenance are inconvenient.

The droop aerator is developed by our company according to the principle of oxygen pfer in water and the characteristics of various aeration devices at present. It overcomes the shortcomings of the traditional aeration device and is an aeration device with high efficiency, convenient maintenance and reliable operation.

The aerator is installed at the bottom of the tank, and is connected with the air branch pipe through the connecting pipe. When it is overhauled, it is necessary to remove the aeration device to be repaired and the connecting pipe from the air branch pipe and lift it up from the water, so that it can repair and replace it without emptying the sewage in the emptying pool.

The aerator stays at a depth of 4 to 5M. When the bubble escapes, its diameter is about 50 m. Such tiny bubbles increase the oxygen contact area and increase the efficiency of oxygen pmission.

Compared with other aeration devices, the aeration device has the following advantages: (1) good aeration effect; second, convenient maintenance and simple maintenance; 3. It is not easy to be corroded and has long service life.

Because the variable microporous aerator is arranged at the bottom of the tank, the slurry of the whole pond is well stirred, which improves the decontamination effect of the aerobic system.