With the development of economy, people's living standards are improving day by day and the rapid development of industry, more and more domestic waste and industrial waste are produced. Timely treatment of domestic and industrial waste can reduce the pollution of waste to the environment and improve people's living environment, in line with the concept of sustainable development and environmental protection. Garbage incineration is currently a relatively common process for the treatment of domestic and part of industrial waste. During the maturing process of garbage into the garbage pit, garbage leachate will be produced. The garbage leachate has the characteristics of high organic load, high salt content, high ammonia nitrogen, etc. Difficulties in pollution control; polyacrylamide plays an important role in the landfill leachate treatment process.
1. Landfill leachate has the following characteristics:
(1) The water quality is complex: the leachate contains a variety of pollutants, and the concentration often varies greatly. Landfill leachate contains not only oxygen-consuming organic pollutants, but also a lot of pollutants such as metal ions and ammonia nitrogen, and generally contains toxic and harmful organic pollutants. The water quality is very complicated.
(2) High COD concentration: The COD in landfill leachate can reach up to 60,000 mg/L. It has the characteristics of extremely high COD and BOD5 concentration, high toxicity, and difficult to handle.
(3) Large changes in water quality and water quality: The leachate water quality of the waste incineration plant varies greatly. The factors affecting the water quality and quantity of landfill leachate are mainly the nature, season and weather of the local garbage (rainfall and snowfall).
Second, the treatment process of landfill leachate:
1. Treatment with membrane technology
Disc tube reverse osmosis DTRO membrane has the characteristics of good anti-pollution, high membrane flux, and long service life. The front end of the disc tube reverse osmosis DTRO membrane can be directly treated by the sand filter to protect the leachate, even at high Under the turbidity, high SDI value, high salinity, and high COD, it can also run cost-effectively and stably. It is currently a mature technology that can guarantee the stability of leachate effluent and continue to meet the national first-level or second-level discharge standards.
2. Biochemical + membrane process
After the biochemical treatment of the leachate, the membrane process is the most commonly used leachate treatment method. The commonly used water treatment agent in the biochemical treatment process is polyacrylamide. The polyacrylamide is made of acrylamide (AM) monomer through free radicals. The water-soluble linear high molecular polymer formed by initiation of polymerization has good flocculation, can adsorb suspended particles in water, and acts as a bridge between the particles, so that the fine particles form a relatively large floc and accelerate the precipitation speed. The effluent quality of this process is good, which can reach the standard of reuse water. It also has a high resistance to changes in the quality and volume of the leachate and high operating stability. After the membrane separation treatment, the effect of the pollutants is obvious, and the separated effluent can meet the corresponding national discharge standards. Moreover, the membrane technology has a continuous operation, a high degree of mechanization, and is easy to manage, and the instability of water quality has little effect on the effect of membrane treatment.
3. Biochemical + advanced oxidation + advanced treatment
The leachate has high organic pollutant concentration and good biodegradability. The biochemical treatment process is a relatively thorough and economical process for treating high-concentration organic wastewater. It can greatly degrade organic pollutants under relatively economic conditions, and at the same time exert nitrogen and phosphorus removal. The result is that the overall treatment cost of leachate is more economical. Since the leachate also includes many refractory macromolecular organic substances, after treatment with biochemical treatment technology, some “inert COD” that cannot be biodegraded and adsorbed will always remain. Engineering practice shows that the use of a variety of biochemical treatment processes can reduce the CODcr of leachate to less than 1000mg/L, and the removal rate is very considerable, but the effluent generally cannot directly meet the requirements of the discharge standard.
The selection of polyacrylamide for landfill leachate treatment is mainly based on the type of charge carried in the sewage water quality. According to the characteristics of the water quality, the choice of cationic polyacrylamide, anionic polyacrylamide, or zwitterionic polyacrylamide, etc., process Generally, it is from the small test in the laboratory to the big test in the manufacturer, and the final product selection is finally determined, and the specific problems are analyzed. Guangdong Shouxin Environmental Protection Technology Co., Ltd. is a company specializing in polyacrylamide for landfill leachate. According to the characteristics of the customer's on-site sewage water quality, free experimental selection can be selected to select polyacrylamide products with better effects and lower prices.