Application of Silicon Carbide UF membrane in landfill leachate

landfill leachate treatment.png

Background

Landfill leachate is a kind of high concentration organic wastewater with complex composition. If it is allowed to be discharged, it will seriously pollute the surrounding farmland and water system, especially the groundwater or the surrounding environment, and the consequences will be more serious. In order to protect the environment, it is necessary to treat the leachate. Landfill leachate has the characteristics different from the general urban sewage: high concentration of BOD5 and COD, high metal content, large change of water quality and quantity, high content of ammonia nitrogen, imbalance of microbial nutrient elements, etc.

In terms of time, the treatment of leachate has gone through three stages:

●The first stage: aerobic treatment process (contact oxidation, SBR, oxidation ditch, etc.)

(the treated effluent can meet or even fail to meet the discharge standard of 97 years old)

●The second stage: anaerobic (UASB, etc.) + aerobic treatment process

(the treatment effect of ammonia nitrogen is not good, which can only meet the second and third level emission requirements of the old standard)

●The third stage: MBR + Advanced Treatment Process & two stage DTRO reverse osmosis

(it can steadily meet the requirements of the new emission standard)

At present, the process of physicochemical + biochemical + deep membrane treatment + evaporation process as landfill leachate treatment process has been very mature.

The deep treatment is divided into two types, membrane deep treatment and advanced oxidation depth treatment. From the perspective of operating cost, the advanced treatment of membrane method is mainly adopted, including tubular ultrafiltration membrane, immersion flat membrane, nanofiltration membrane, reverse osmosis membrane, etcAs the pretreatment unit of deep membrane process, ultrafiltration technology is a key link in the whole process. The main ultrafiltration technologies used in landfill leachate are immersion ultrafiltration and external tubular ultrafiltration.


In submerged ultrafiltration technology, the core advantages of SiC flat membrane compared with PTFE hollow fiber membrane are as follows:ultrafiltration membrane 1.png

1. Compared with the actual operating flux of 8 ~ 15lmh, SiC flat membrane can easily reach 25lmh ~ 40lmh;

2. Unique membrane module structure design, diaphragm can be easily replaced with one membrane element as the smallest unit;

3. The service life of PTFE material is twice as long as 10 years.



landfill leachate treatment 4.png   External tubular ultrafiltration technology, SiC tubular membrane compared with PVDF organic tubular ultrafiltration membrane core advantages:

    1. Compared with the actual PVDF material of 60 ~ 120lmh, the running flux of SiC tubular membrane can easily reach 100lmh ~ 200lmh;

    2. Chemical cleaning has zero corrosion, flux recovery rate ≥ 98.2%, and can accept     high temperature steam purging;


          VS

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     3. Five times the service life of PVDF material, the service life is up to 15 years;

     4. Reliable operation flux is guaranteed in the service life cycle. The single membrane element can be disassembled independently for thermodynamic   regeneration, and the flux can be restored 100%



Application highlights of SIC flat sheet membrane.

Technical highlights 1: adjustable diaphragm spacing

flat sheet membrane landfill leachate.png

      

 Diaphragm spacing can be selected








Diaphragm spacing20mm
 33mm46mm
Number of membrane elements filled in a single module

16

118
Filtering area of single component2.8㎡2.0㎡1.4㎡
Maximum thickness of cake layer71218



Technology highlight 2:Filter cake layer control technology, filter cake can be increased to a maximum thickness of 18mm


landfill leachate filter.png



◆The membrane surface with high negative charge can ensure excellent pollution resistance in a wide range of pH.

◆Low ambient pressure (less than 700mbar), filter cake layer structure can always maintain a loose state.

◆When the pre-set cleaning conditions are met, it is easy to clean the negative charged substances in water from the membrane surface, such as bacteria, MLSS, transparent polymer particles and oil substances.


Technology highlight 3: efficient cleaning method

Silicon carbide flat plate membrane works.png

The agent sprayed on the surface of the membrane can quickly penetrate into the microporous structure of the silicon carbide membrane surface, so that the pollution factor can be quickly digested after being soaked by the agent, and this cleaning method can ensure that the water producing side will not be polluted by chemicals.

Application highlights of SIC tubular membrane

landfill leachate 6.png

Technical highlight 1 : flexible and diversified installation mode, membrane module can be installed vertically or horizontally, supporting multiple branches in series (≤ 8)

                                                        Model of silicon carbide tubular membrane for landfill leachate
Membrane materialPure silicon carbide
Membrane shell material

UPVC、FRPP、316L

model

JMtech-SICT-46-8-19-530、

JMtech-SICT-46-8-19-1230

Effective filtration area of single branch

0.587㎡

Filtration accuracy

10nm---40nm

Number of channels19
Single channel diameter8mm
Membrane element length1230mm
End face geometry1605582290250434.png


Technical highlight 2: the membrane element supports thermodynamic regeneration and can obtain reliable operation flux commitment (the flux can be restored to more than 99.5%) within the service life cycle

silicon carbide membrane regeneration.png