WU Guo-dong

(SchoolofEnvironmentalScienceandEngineering,QingdaoUniversity,QingdaoShandong266000，China)

Performance and mechanisms of salt-torrent ANAMMOX process

WU Guo-dong

(SchoolofEnvironmentalScienceandEngineering,QingdaoUniversity,QingdaoShandong266000，China)

Wide application of seawater made the biological denitrification in the saline wastewater treatment become a difficult problem, expounds the salt effect on anaerobic ammonium oxidation,summarizes the salt resistance of anaerobic ammonia oxidation microorganism acclimation, points out that the two kinds of mechanism of salt stress on the denitrification microbes,and to make a optimization strategy on salt stress.

Anammox;Salt acclimation;Salt strategy

Due to the lack of fresh water resources,some coastal cities began to adopt the method of direct or indirect use of sea water which can save the total fresh water.Sea water replace the industrial cooling water and flushing water what can promote water resource structure optimization. The large area used which results in the waste water of the water salinity is higher,causing the problem of high salt wastewater treatment.Use of salt-tolerant type microbial Marine wastewater treatment is an effective method.Therefore,the development that can tolerate the efficient strains of the water is necessary.This tolerance species of sea water can be derived from two ways,one is the development of Marine biological resources,the other is fresh water sludge seawater domestication[1].The first way due to the requirement for geographical and other special conditions are often limited,compared with the first way,the second approach is particularly important.

Anaerobic ammonia oxidation (Anammox)is a kind of biological denitrification process that make NH4+as electron donor,NO2-for electron acceptor,nitrogen and nitrate nitrogen for the product.Because of its economical and high efficiency in the nitrogen removal performance. Anaerobic ammonia oxidation process efficiency,economy,is expected to become wastewater biological nitrogen removal of upgrading technology,it has a good application prospect[2].Now they find the anaerobic ammonia oxidation bacteria including six genera,including freshwater environments ofanaerobic ammonia oxidation bacteria has five genera,only a“Scalindua”belongs to the distribution of Marine ecosystem[3].Some researchers have domesticated and screening salt-tolerant denitrification biological.

Sharply higher osmotic pressure can lead to high salt environment cell plasmolysis,microbial cell membrane and bacterium enzyme in the body,on the metabolism of Anammox bacteria growth inhibition,and ultimately cause cell death[4].To realize anaerobic ammonia oxidation process in such effective application in wastewater treatment,high salt water environment must be considered potential negative effects of anaerobic ammonia oxidation,developing high efficiency and stable under high salt environment regulation method of anaerobic ammonia oxidation process.Through domestication,freshwater ecosystems of anaerobic ammonia oxidation bacteria can tolerate a certain concentration of salt. Freshwater Anammox sludge after domestication can be obtained under 30‰ salinity better performance of nitrogen,total nitrogen removal rate can reach 2.80 kgN/(m3.d)[5].

Microbial mainly through two ways to cope with the high Salt stress, respectively is:microbes increased ion concentration inside the cell, especially potassium ion concentration,to balance the osmotic pressure,so that intracellular enzyme can adapt to the new environment(Salt In Cytoplasm,SI strategy for short)and the intracellular accumulation of Compatible Solutes,make external high osmotic pressure balance In the Cytoplasm(Compatible Solutes,CS strategy)[6].The researchers found that when the concentration of Na+anaerobic treatment system of up to 7000～8000mg/L,can severely inhibit the growth of anaerobic microorganisms. If adding suitable amount of K+,inhibiting effect to fall 60%,this effect is called the antagonistic effect[7].The addition of compatible solutes has previously been shown to encourage sludge activity undersaline condition.CS is low molecular weight organic compounds,they are not harmful interaction with molecules,including betaine，trehalose and so on. They can increase the cell osmotic potential,leading to maintain a proper turgor pressure.

The above two methods can improve the efficiency of anaerobic ammonia oxidation treatment of wastewater containing water,make its salinity tolerance,and have good denitrification effect.For direct application of anaerobic ammonia oxidation treatment wastewater containing water to provide theoretical support.

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