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    Home > Chemicals Industry > Chemical Technology > Using microorganisms to treat water pollution

    Using microorganisms to treat water pollution

    • Last Update: 2021-06-18
    • Source: Internet
    • Author: User
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    The use of microorganisms to control water pollution is currently an internationally popular pollution control technology
    .

    (1) Biopolymer materials for treatment of heavy metal wastewater pollution, Jiangsu Kunshan Industrial Research Institute Huake Biopolymer Materials Research Institute has successfully applied biopolymer materials to heavy metal wastewater treatment.
    After production and practice tests, the project is called "Bio-based The scientific research results of “technical industrial heavy metal wastewater treatment-reclaimed water reuse system” have shown good prospects for industrialization
    .


    The γ-polyglutamic acid biological heavy metal wastewater treatment device used in the production of "Biotechnology-based industrial heavy metal wastewater treatment-reclaimed water reuse system" uses the γ -polyglutamic acid biological heavy metal wastewater treatment system to treat wastewater, 1t Only 200g of biopolymer material (biological capture agent) can be used for water


    (2) Cultivation of high-efficiency strains to treat many synthetic organic compounds that are accumulated in the environment and cause pollution in the environment by cultivating high-efficiency strains.
    They are initially resistant to microbial attack and are difficult to degrade
    .


    When environmental conditions change, some microorganisms form new strains through natural mutations, and it is more likely that through the formation of induced enzyme systems, they have new metabolic functions, which can degrade or transform foreign compounds


    The “military bacterial group” pollution treatment method pioneered by Huazhong Agricultural University has been successfully applied in the treatment of lakes in the central city of Wuhan
    .


    At the beginning of September 2008, the monitoring results from the treatment unit showed that the water quality of the 9 lakes treated with microbiological methods has improved significantly within one month


    There are many studies on screening and separating strains with high degradation activity for the treatment of printing and dyeing wastewater
    .


    Shewanella putrefaction can effectively remove a variety of dyes commonly used in production under suitable conditions, and the removal rate of reactive brilliant red dyes can reach 99% to 100% within 6 hours


    (3) Aerobic denitrification and denitrification technology In recent years, the phenomenon of aerobic denitrification has attracted the interest of many researchers.
    The use of aerobic denitrifying bacteria can also achieve denitrification under aerobic conditions.
    This technology can achieve simultaneous nitrification and denitrification.
    That is to say, aerobic denitrification can occur in the same reactor as the nitrification reaction, which greatly reduces the system space and engineering cost, and also reduces the operation difficulty and operating cost; the OH- released by denitrification can partially compensate for the consumption of the nitrification reaction.
    The alkali, can make the pH value in the system relatively stable, and the aerobic denitrifying bacteria is easier to control
    .


    In recent years, a variety of aerobic denitrifying bacteria have been isolated and studied, and the mechanism research and application research of aerobic denitrification technology have also made certain progress.


    (4) Highly active microorganisms and microbial activation technology to treat polyvinyl chloride (PVC) wastewater Xinjiang Tianye Company uses high-active microorganisms and microbial activation technology to treat PVC polymerization centrifugal mother liquor wastewater, and the wastewater treatment effect has reached the world's advanced level
    .


    This process effectively removes the sludge deposited on the filler by quantitatively adding cultured and domesticated highly active microorganisms and microbial activators in the contact oxidation tank, establishes a new highly active microbial film, and maintains the biofilm Therefore, the treatment efficiency of the original wastewater treatment facility is greatly improved, and the treatment capacity is doubled without changing the existing equipment and facilities


    (5) Aerobic granular sludge technology Aerobic granular sludge is a microbial immobilized aggregate formed under aerobic conditions, which is similar in structure to biofilms.
    The particle size is similar to the thickness of biofilms, generally between 0.
    30~ Between 8.
    00mm, the sphericity (aspect ratio) is generally greater than 0.
    6
    .


    The particle size of activated sludge is generally less than 0.


    In order to shorten the time for sludge granulation, speed up the start-up of the reactor, and enhance the ability of granular sludge to remove ammonia and phosphorus, research on aerobic granular sludge has gradually attracted attention in recent years
    .


    On the whole, aerobic granular sludge has the following advantages


    ① Aerobic granular sludge can not only treat low-concentration wastewater, such as urban sewage, but also achieve a high removal rate when treating high-concentration organic wastewater without subsequent treatment
    .

    ②The granular sludge has a compact structure, which can weaken the influence of toxic substances on microorganisms and enhance the protection of some more sensitive bacteria (such as nitrifying bacteria), thus helping to improve the processing capacity and stability of the system
    .

    ③Similar to anaerobic granular sludge, aerobic granular sludge has good settling performance, which can effectively increase the sludge concentration and volume load of the reactor
    .

    ④ Aerobic granular sludge has a strong ability to remove nitrogen and phosphorus
    .

    ⑤Compared with anaerobic granular sludge, aerobic granular sludge has a shorter start-up period and can be cultured and operated at room temperature
    .

    In general, aerobic granular sludge has a lower ability to degrade organic pollutants than anaerobic granular sludge
    .

    Aerobic granular sludge technology is applied to remove heavy metal ions in wastewater.
    Studies have shown that extracellular polymers (EPS) accumulated on the surface of aerobic granular sludge play a very important role in the process of adsorbing heavy metals
    .
    The aerobic granular sludge has a strong adsorption effect on Cd 2+ , Cu 2+ , Zn 2+ and Pb 2+ , and the adsorption and removal capacity for Pb 2+ is the strongest
    .
    The results of the study on the adsorption of Ni 2+ by aerobic granular sludge (pH 2~7) show that there is an electrostatic attraction between the granular sludge and Ni2+.
    In addition, the aerobic granular sludge absorbs Ni 2+ and simultaneously reduces K + , The release of metal ions such as Ca 2+ indicates that the mechanism of Ni2+ adsorption by aerobic granular sludge is ion exchange
    .

    In terms of nitrogen and phosphorus removal, MBR is inoculated with aerobic granular sludge to establish a granular sludge membrane bioreactor (GMBR), which organically combines aerobic granular sludge technology with membrane technology, focusing on sequential batch anaerobic-aerobic Organic matter removal and SND effect of long-term operation of GMBR in operating mode
    .
    The test results show that GMBR has good organic matter removal and denitrification effects.
    The removal rates of TOC, ammonia nitrogen and total nitrogen of GMBR are 65.
    7%~98.
    6%, 85.
    4%~98.
    9% and 66.
    1%~95.
    1% respectively; In the SBR system for sludge dephosphorization and denitrification, the phosphorus concentration in the sewage after 4h anoxic reaction was measured, and it was found that the phosphorus concentration dropped from 108.
    1mg/L at the end of anaerobic to 32.
    2mg/L, and phosphorus was absorbed by hypoxia.
    The rate is 18.
    9mg/(L·h), denitrifying phosphorus accumulating bacteria accounted for 73.
    1% of all phosphorus accumulating bacteria in this system
    .
    This shows that a large number of denitrifying phosphorus accumulating bacteria in aerobic granular sludge have made a great contribution to phosphorus removal
    .
    The Delft University in the Netherlands has successfully extended the aerobic granular sludge process to pilot and industrial application scales by increasing the proportion of phosphorus-accumulating bacteria
    .

    In the treatment of high-concentration organic wastewater, foreign scholars use dairy wastewater to cultivate aerobic granular sludge in the SBR reactor.
    After the sludge is granulated, the removal rates of total COD, TN, and TP are 90%, 80%, and 67, respectively.
    %
    .
    Domestic scholars use soy product processing wastewater to cultivate aerobic granular sludge.
    When the organic load is 6kgCOD/(m 3 ·d), the COD removal rate is as high as 99%
    .

    It can be predicted that, as a new type of wastewater biological treatment process, aerobic granular sludge has advantages in wastewater treatment unmatched by other processes due to its unique physical and chemical properties, so it has a wide range of application prospects in wastewater treatment
    .
    At present, the main reason hindering its industrialization is the lack of in-depth research on the formation mechanism of aerobic granular sludge, and there is no complete set of theoretical guidance
    .
    In addition, in the process of cultivating aerobic granular sludge, due to the differences in the reactor, operating conditions and the function of the cultivated sludge, there are still great controversies in certain research aspects, such as formation mechanism, granulation process, and key influences.
    and other factors
    .
    At present, when the actual wastewater is used to cultivate aerobic granular sludge at home and abroad, some easily biodegradable wastewater related to the food industry is mostly used, and there is no use of refractory biodegradable substances as a substrate to cultivate aerobic granular sludge
    .
    Future research directions should focus on the granulation mechanism, the processing capacity of granular sludge, the influencing factors of aerobic granular sludge formation, long-term operation stability and the microbial characteristics of granular sludge
    .

     

     

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