A method and system for synergistic sludge dewatering treatment of aged leachate in a landfill

Abstract

The invention discloses a method and a system for synergistic sludge dewatering treatment of aged leachate in a landfill. The method comprises the following steps: mixing sludge and aged leachate, adding alkali for alkalization treatment and dehydration treatment, and completing Co-processing of aged leachate and sludge. The system includes an alkalizing unit and a dehydrating unit. The method for synergistic sludge dewatering treatment of aged leachate of a landfill in the present invention takes the aged leachate of the landfill as the dilution water for sludge dewatering treatment, and adds alkali for alkalization treatment and dehydration treatment, so as to improve the sludge dewatering process. At the same time of wall effect and dehydration performance, it can also realize the resource utilization of aged leachate, which has the advantages of simple process, short process, convenient operation, high treatment efficiency, low dosage of chemicals, low energy consumption, low cost, good dehydration effect, and two At the same time, the pH of the obtained filtrate is easy to adjust, the conductivity is suitable, and the subsequent advanced treatment is easy, so it has a good use value and a good application prospect.

Description

technical field [0001] The invention belongs to the technical field of sludge disposal, and relates to a method and a system for synergistic sludge dewatering treatment of aged leachate of a landfill. Background technique [0002] At present, the commonly used methods for dehydration treatment of municipal sludge (90% moisture content) include filter press dehydration, thermal drying dehydration, electrolytic dehydration and the like. Filtration press dewatering (high-dry sludge dewatering) generally requires the addition of a large amount of inorganic salt compound / inorganic salt + PAM / lime, etc. After the sludge is conditioned and tempered until the dewatering performance is greatly improved, it is dewatered in a high-pressure diaphragm plate and frame machine. However, due to the need to add a large amount of the above-mentioned chemicals in this method, it will bring a series of problems: (1) the moisture content of the sludge after dewatering is still as high as 50%, an...

AI Technical Summary

Problems solved by technology

Press filter dewatering (sludge high-dry dehydration) generally needs to add a large amount of inorganic salt compound / inorganic salt + PAM / lime, etc., after the sludge is tempered until the dehydration performance is greatly improved, it is dehydrated by a high-pressure diaphragm plate frame machine. But owing to needing to add a large amount of above-mentioned medicaments in this method, can bring a series of problems: (1) the water content of the sludge after dehydration is still as high as 50%, is difficult to reduce to below 45%; (2) adding of inorganic salt will increase Conductivity and other indicators, resulting in serious corrosion of treatment equipment due to the improvement of electrochemical corrosion performance, and the high conductivity is difficult for biochemical treatment; (3) The large amount of inorganic salt will increase the ash content in the sludge, resulting in a large amount of sludge production At the same time, it is also not conducive to the subsequent resource utilization of sludge. For example, when the mud cake is used for landfill treatment, due to the high content of inorganic salts, it is easy to affect the stability of the pile and increase the risk of secondary seepage of salt, while it is used for incineration treatment (4) Adding a large amount of inorganic salts will also change the properties of the filtrate, such as a large amount of inorganic salts will be introduced in the filtrate, resulting in complex components of the filtrate and reducing the biochemical properties of the filtrate. , and it is easy to cause secondary pollution (such as iron salts are easy to cause water chroma to increase, aluminum salts are easy to cause aluminum ions in water to exceed the standard); (5) In addition to strong oxidant pre-conditioning, high-temperature anaerobic digestion produced by other process The ammonia nitrogen value in the sludge press filtrate is generally high, and the overall filtrate is difficult to treat due to the imbalance of C / N ratio. Ferrous sulfate + H 2 o 2 Fenton-like reaction method for conditioning can effectively reduce the ammonia nitrogen value, but the use of Fenton reaction has the problems of unstable sludge conditioning, severe corrosion of equipment, and high cost of chemical consumption

Obviously, in the above-mentioned filter press dehydration method, a large amount of conditioner is added, which is not conducive to the subsequent incineration / recycling of sludge

Thermal drying dehydration generally adopts mechanical dehydration + thermal dehydration dehydration. The conditioning method used in mechanical dehydration is to add PAM pretreatment to 70% water content and then heat drying. Compared with thermal drying alone, the cost will definitely decrease, or adding and pressing filter The dehydration conditioning agent improves the dewatering performance of the sludge, dehydration to 60% moisture content and then heat drying, the cost is significantly reduced, but there are the same follow-up problems caused by the addition of high-dry dehydration agents in filter press dewatering; at the same time, heat drying dehydration is also There is a problem of high operating costs

The investment cost of electrolytic dehydration equipment is too high. Even if the water content can be reduced by chemical conditioning and then electrolytic dehydration is performed, the operation and maintenance costs are still high

[0003] Alkali-thermal method is as the method for conditioning sludge, as the additive of lime as alkaline-thermal method, can improve the dewatering effect of sludge, but still there is following deficiency: (1) the consumption of lime in the prior art is at least 1 / 2 of the sludge quality 5%, the amount of lime is relatively large, and the pH value of the conditioning system is exceeded 13, and the filtrate needs a large amount of acid to adjust the pH, and lime needs to be used in combination with other medicaments, which will increase equipment costs and medicament costs; (2) reaction The temperature is low, the sludge wall is not completely broken, the subsequent dehydration effect is poor, and the reaction time is long, resulting in low treatment efficiency; (3) the sludge dehydration effect is about 50%, and the moisture content of the sludge is still high, and It is more difficult to further reduce the moisture content of sludge

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