Extended reading: Due to the high water quality concentration of domestic permeate, the concentrated liquid is directly recharged to the landfill storage area without treatment measures, penetrated through the garbage heap, collected by the permeate collection system and discharged into the adjustment tank again, and then enters the permeate treatment station. It is an inner loop and has the following shortcomings:

1) The degradation of pollutants mainly depends on the garbage heap. The garbage heap is in an anaerobic environment. There are mainly two types of bacteria in the system: acid-producing bacteria (heterotrophic bacteria) and methanogenic bacteria (autotrophic bacteria), acid-producing bacteria. Bacteria grow faster than methanogens, methanogens are more sensitive to pH value, and the most suitable pH value range is about 6.8~7.2. Methanogens will be inhibited and the numbers of the two types of bacteria will be unbalanced (fresh permeate contains a higher concentration of VFA and is biodegradable, so acid-producing bacteria grow rapidly, which is more likely to occur), allowing the permeate to stay In the acid production stage, the pollutants cannot be completely decomposed, resulting in a high concentration of organic matter in the influent of the DTRO system, which accelerates the pollution of the DTRO membrane.

2) For the accumulation of difficult biodegradable organic matter and inorganic salts in the system, the influent concentration of the reverse osmosis system will be higher and higher. The higher the salt content, the higher the osmotic pressure, and the water production will decrease when the inlet water pressure remains unchanged. In the initial stage of landfill, the permeate concentration is low and the water production rate is high, which can usually reach 80%, and in the middle and late stage, it can be reduced to 70% or even lower, thereby shortening the service life of the membrane and greatly increasing the operating cost.

3) There are three main ways of refilling the concentrate: direct refilling to the landfill layer (during the stratified compaction of the waste, the permeate is poured on the working surface), surface refilling (usually using perforated pipe sprinkling) , Recharge under the covering layer (laying a pipe network under the covering layer in the middle of the landfill or using gas-conducting gabions to recharge). The first two methods will accelerate the volatilization of malodorous gas and affect the landfill operation. The third method is easy to form a short flow (through the gas guide gabion and the bottom permeate collection system directly into the regulating tank), and the pollutants are not effectively passed through the garbage layer. degradation. This article is produced by the integrated waste permeate treatment equipment manufacturer

4) Recharge sends the organic matter in the permeate back to the landfill, which speeds up the gas production rate of the landfill and easily causes safety problems.

In view of the analysis of the two-stage DTRO process and the transformation process of the permeate treatment station using the DTRO process in the early stage in China, the following improvement measures are proposed:

1) In the initial stage of recharge of the newly built landfill, in order to prevent the excessive proliferation of acid-producing bacteria, maintain the balance of the number of acid-producing bacteria and methanogens to ensure the degradation effect of the garbage heap, and reduce the concentration of organic pollutants in the permeate, it can be Two methods were used: intermittent reinjection (stopping after a short time of reinjection), and inoculation with methanogens. This article is produced by the integrated waste permeate treatment equipment manufacturer.

2) During the landfill operation, measures should be taken to ensure the effect of recharge, prolong the residence time of the permeate in the garbage heap, and fully degrade the pollutants.

3) A biochemical treatment unit is added before the DTRO treatment unit. For the later period when the ammonia nitrogen concentration is high and the carbon source is insufficient, consider adding an external carbon source.

4) Treating the concentrated solution (such as Fenton reagent method, ozone oxidation method, etc.), the effect is more obvious for the late permeate containing a large amount of difficult biodegradation, which can reduce the influent concentration of the DTRO system, improve the water production rate, delay the Membrane fouling, thereby reducing operating costs.