How to deal with the sewage in paper mill?

Due to the large amount of pulp and paper wastewater, the difficulty of treatment and the continuous improvement of environmental protection standards, water treatment costs have also increased in corporate expenditures. Here are a few ways to discuss how to save energy and reduce emissions.

Anaerobic treatment facility

At present, there are many anaerobic treatment facilities used in the sewage treatment of pulp and paper enterprises, such as hydrolysis acidification tank, UASB, ABR and IC. Most enterprises have built hydrolytic acidification tanks. For enterprises with low COD concentration, it is recommended to increase the sludge concentration of the hydrolysis acidification tank and change the hydraulic distribution to fully exert the effect of anaerobic treatment. For enterprises with high COD concentration, it is recommended to increase Anaerobic reactors are built; for companies that already have anaerobic reactors, operating parameters should be optimized to allow the anaerobic treatment facility to operate better.

Aerobic treatment facilities

The aerobic treatment facility is the most energy-intensive part of wastewater treatment, accounting for 60% to 70% of the energy consumption of the entire treatment system, so it is the focus of energy conservation.

Control of dissolved oxygen concentration

According to the results of the US Environmental Protection Agency, when the air volume is controlled by DO, energy can be saved by 33%. Monitoring of DO concentration from a process perspective can reduce or avoid excessive aeration and unnecessary nitrification. In addition, the DO concentration can be controlled at 1~2mg/L in actual engineering operation.

In actual operation, scientific and reasonable control methods should be selected according to the specific conditions, and the nitrogen content and DO concentration in the water should be controlled to reduce unnecessary nitrification, thereby achieving energy saving purposes.

Blower room and piping design

When constructing the blower room, the reasonable ventilation system design should be based on the type of blower, so that the drum extension room has better ventilation effect, and at the same time, the airflow short circuit should be avoided as much as possible in the ventilation system design. Short and straight when arranging pipes to reduce losses.

Other treatment facilities

Lift pump station

Lifting pumping stations are also a major energy consumer of sewage treatment systems, so how to make lift pumps work efficiently is very meaningful for energy saving.

Reasonable determination of the lift, select the sewage lift pump with the flow and lift as far as possible to meet the design requirements. In the overall arrangement, it should be as compact as possible. When connecting the pipelines, it should be short and straight, minimize the loss of the head, reduce the number of pumps, and use high-efficiency pumps. When it is necessary to adjust the flow rate, the frequency conversion speed regulation technology should be used to replace the valve or the regulating baffle. In actual operation, it is proved that the use of the frequency conversion technology can save energy by 40% to 60% compared with the use of the baffle and the valve to adjust the flow rate.

Precipitation pool energy saving

For the energy saving of the primary and secondary sinking tanks, it is mainly in the way of sludge discharge and the running time of the scraper. It is most energy-efficient to use static mud, and the scraper can be adjusted to intermittent operation. As for the interval time, it should be determined according to the actual situation, so as not to cause the sludge to float.

Sludge dewatering system energy saving 

First of all, in the sludge dewatering, it is necessary to control the reasonable dosage of the agent, try to use the current distribution, and how much to use, to save the dosage. Second, we must choose an efficient and energy-saving sludge dewatering equipment. Finally, when designing the sludge return system, a reasonable return pump should be selected; when arranging the pipeline, the pipeline loss should be minimized. The energy saving and consumption reduction of sewage treatment projects is a comprehensive work involving many links such as process, self-control and equipment. The multi-disciplinary intersection and the integration of various technologies are the inevitable trend of its development.