Treatment method of high-salt and high-hardness organic wastewater in fly ash landfill

Abstract

The invention relates to a treatment method of high-salt and high-hardness organic wastewater in a fly ash landfill, which comprises the following steps of: sending percolate in different reservoir areas in a fly ash landfill into an adjusting tank, and stirring for homogenizing adjustment; pumping wastewater into a primary reaction tank to carry out primary oxidation on the wastewater by an oxidant, enabling the wastewater to flow into a secondary reaction tank for a transition reaction with a catalyst, enabling the wastewater in the secondary reaction tank to automatically flow into a tertiary reaction tank, fully stirring, carrying out advanced oxidation reaction to degrade organic matters in the wastewater, and carrying out complex breaking treatment on heavy metals; enabling the effluent to automatically flow into a coagulative precipitation tank, adding an alkali liquor metal recapturing agent and a flocculating agent and fully stirring, enabling supernatant obtained after solid-liquid separation to sequentially pass through a quartz sand filter, a multi-stage activated carbon filter and a heavy metal adsorption resin tank, and enabling the effluent to enter a water outlet tank to be discharged; and enabling odor to react with absorption liquid in an absorption tower and then discharging the odor. The method is simple in technological process, stable in operation, low in requirement for inflow water quality and higher in treatment efficiency, and the investment cost is greatly reduced.

Description

technical field [0001] The invention relates to a method for treating high-salt and high-hardness organic wastewater in a fly ash landfill, and belongs to the technical field of high-salt and high-hardness organic wastewater. Background technique [0002] The development of treatment technology for fly ash and slag that enters incineration after pretreatment of medical waste has been relatively mature. At present, the commonly used treatment methods include safe landfill method, solidification / stabilization method, melting treatment method and wet chemical treatment method. The safe landfill method is a method in which waste incineration fly ash and slag are processed on site and then sent to a safe landfill for landfill treatment. Solidification and stabilization technology is one of the main methods for dealing with toxic and hazardous wastes in the world. Its main function is to make the heavy metals and other pollutant components in fly ash and slag chemically inert or c...

AI Technical Summary

Problems solved by technology

[0004] Membrane method and evaporation have extremely high requirements for calcium and magnesium ions in the feed. Excessive calcium and magnesium ions will cause blockage or even breakdown of membrane tubes, and will also cause evaporation scaling to affect heat transfer efficiency, resulting in high investment and maintenance costs.

However, the total hardness of leachate from medical waste incineration plants can reach up to 4000mg / L, and after dehardening, it still has 400-500mg / L, which cannot meet the requirements of membrane method and evaporation.

[0005] The front end of the conventional process generally uses advanced oxidation (mainly Fenton oxidation) to break the network and remove COD. The CODcr removal efficiency is about 50%. When the influent CODcr is 1000mg / L, it can basically be lower than 500mg / l after treatment. Guarantee measures, the basic COD discharge can fully meet the standard, but when the chloride ion in the leachate exceeds 20,000 mg / L, the efficiency of Fenton oxidation gradually decreases, and the general CODcr removal rate is only 40% under conventional conditions, even if there are follow-up safeguard measures. Discharge

In order to improve the oxidation efficiency and CODcr removal rate, the dose of oxidant and the reaction conditions are increased, but excessive oxidant will decompose under acidic conditions to generate a large amount of chlorine gas, which is a safety hazard, and the residual chlorine in the effluent is too high to meet the standard requirements, especially the oxidant After the excessive amount enters the sedimentation tank, the continuous decomposition of the oxidant will lead to poor sedimentation effect, and the sludge will float up and cannot be effectively sedimented

Therefore, the existing technology is still unable to stably treat this type of wastewater and ensure that the effluent is stable and up to standard. Therefore, it is urgent to develop a simple, stable, efficient and economical combined process.

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