Thread Content
I. Origin of landfill leachate Landfill leachate represents a major challenge in urban environmental management. Leachate from waste transfer stations, incineration plants, or landfills is formed from various compounds and decaying materials, containing extremely high concentrations of BOD, COD, nitrogen-containing compounds, phosphorus-containing compounds, organic halides and sulfides, as well as inorganic salts. It not only has a foul odor but also contains many substances that are carcinogenic. Landfill leachate is a type of high-concentration organic wastewater with a complex composition and significant variations in water quality and volume. It has the following main characteristics: high concentrations of pollutants ； High content of organic pollutants, with complex composition ； The proportion of microbial nutrients in the leachate is severely unbalanced ； Water quality changes significantly ； It has a high metal content. There are mainly four sources of landfill leachate: the water contained within the waste itself, water generated by biochemical reactions in the waste, backflow of groundwater, and atmospheric precipitation. Among these, atmospheric precipitation is characterized by its concentrated occurrence, short duration, and recurrence, and it accounts for the largest proportion of the total leachate volume. If it is discharged onto the surface, pollutes the environment, or seeps into the ground, it contaminates water sources and poses a serious threat to the urban environment and human health ； Moreover, the longer waste is stored in landfills, the higher the concentration of its leachate becomes, and the greater the harm it causes. If this leachate is discharged into the environment without treatment, it will lead to severe environmental pollution. For the purpose of environmental protection, it is essential to treat such leachate. Common treatment processes: The discharge standards for landfill leachate are shown in Figure 2; methods for effectively removing harmful components from leachate are also discussed. Landfill leachate generally contains high levels of ammonia nitrogen, and biochemical treatment processes are commonly used to address this issue. Such processes can remove the vast majority of ammonia nitrogen, achieving the desired level of treatment efficiency and stability. As a result, the ammonia nitrogen concentration in the water output from biochemical treatment processes in currently operational landfill leachate treatment facilities is usually higher than the values specified in the design specifications. Currently, many places adopt the standard of (8 ppm); therefore, starting from 2017, in addition to ammonia nitrogen resins being used on a large scale in landfill leachate to treat ammonia nitrogen and reduce its level to below 1 ppm. It is currently used in two applications: first, after the reverse osmosis membrane, an ammonia and nitrogen removal resin is installed; second, after the evaporator in the membrane concentration process, the condensate water is passed through such a resin. Suitable ammonia and nitrogen removal resins include: ① Tulsimer® T-42H, which is a homogeneous strong-acid cation exchange resin, a hydrogen H+/sodium Na+ homogeneous cation exchange resin, suitable for removing ammonia and nitrogen at high concentrations, as well as for use in systems dealing with ammonia and nitrogen at other concentrations. ②Tulsimer®T-42H is a strong-acid cation exchange resin that features a high exchange capacity as well as excellent physical and chemical stability. It can be applied to the treatment of wastewater with high ammonia nitrogen concentrations, enabling the ammonia nitrogen level in the treated water to drop below 0.1 ppm. ③Tulsimer®T-42H, with its uniform particle size, offers advantages that traditional ion exchange resins cannot match: it can reduce pressure loss, extend the lifespan of the resin, ensure high quality of the effluent, and has a wide range of compatibility with different pH levels and temperatures. (1) Technical parameters: (2) Product advantages: ① Ammonia nitrogen can be removed selectively, with the effluent quality reaching below 0.1 ppm ； ②It has excellent stability in water output, ensuring no fluctuations in water quality throughout its effective operating period ； ③A high-purity ammonium salt solution can be obtained, which has high economic value ； (3) Application scenarios: The industries where this product performs best include those involving the removal of ammonia nitrogen from evaporated and condensed water, as well as from water after membrane treatment. It also proves highly effective in treating biochemical wastewater containing trace amounts of ammonia nitrogen in industries such as aquaculture and chemicals, ensuring stable effluent quality and compliance with discharge standards.