水體中反硝化細菌的分離、篩選與初步鑒定

1、水體中反硝化細菌的分離、篩選與初步鑒定邵基倫 環(huán)境工程專業(yè)摘要：當今世界環(huán)境污染日益加重，尤其是水體污染已嚴重影響人們的日常生活與身體健康。水污染是多方面的因素綜合作用，而以氨氮的污染最為廣泛且嚴重。所以控制污水中的氨氮含量是污水處理中的重要內(nèi)容。污水脫氮的基本原理是污水中的含氮有機物首先經(jīng)過微生物的氨化作用轉(zhuǎn)化為氨，硝化細菌的硝化作用，將氨氧化為亞硝酸鹽，并繼續(xù)氧化為硝酸鹽。硝酸鹽經(jīng)過反硝化細菌的反硝化作用轉(zhuǎn)化為氮氣等環(huán)節(jié)成分而釋放到大氣中，從而實現(xiàn)污水脫氮。硝化作用是這一過程中的一個中間環(huán)節(jié)，也是一個重要環(huán)節(jié)。硝化作用是指氨經(jīng)過微生物的作用氧化為亞硝酸和硝酸的過程，由硝化細菌完成。硝化細菌

2、是一類好樣化能自養(yǎng)細菌，包括亞硝化細菌和硝化細菌兩個亞群。硝化細菌能夠利用還原態(tài)無機氮化合物進行自養(yǎng)生長，硝化細菌的生命活動在污水脫氮中起重要作用。由于硝化細菌是化能自養(yǎng)菌，其生長速率很慢，因此硝化、亞硝化細菌的生命活動成為污水脫氮的關(guān)鍵步驟之一。它們能有效降低水體中氨氮及亞硝酸氮的含量，對水產(chǎn)養(yǎng)殖業(yè)及環(huán)境保護具有重要意義。硝化細菌是生物硝化脫氨中起主要作用的微生物，直接影響硝化效果和生物脫氨的效率。因為硝化細菌、亞硝化細菌在污水脫氮中的特殊意義，對這類微生物的研究受到廣泛關(guān)注。氨和亞硝酸分別是亞硝化菌和硝化菌的唯一能源。對于硝化細菌來說生長環(huán)境中的溫度對其影響較大，pH值和鹽度的影響相對較小

3、。大多數(shù)硝化細菌的合適生長溫度為1038 ，高于20時硝化細菌的活性較高，但超過38消化作用將會消失。當環(huán)境氣溫低于 20時，氨的轉(zhuǎn)化會受到影響。一般認為，適宜硝化菌和亞硝化菌生長介質(zhì)的pH值分別為6.08.5和6.08.0。水體DO的高低影響到好氧、厭氧微生物的比例，大多數(shù)研究人員認為DO的濃度應(yīng)當控制在1.02.0mg/L,低于0.5 mg/L時硝化作用明顯減弱。另外,碳氮比、堿度等對硝化及脫氨均有影響。本實驗采用人工培養(yǎng)基方法富集培養(yǎng)硝化細菌研究了富集培養(yǎng)過程中硝化與亞硝化細菌的結(jié)構(gòu)和性質(zhì)變化。結(jié)果表明，在25-28，pH758.5，D0 2-5mgL，氨氮濃度100150mgL條件下，

4、經(jīng)過19d和15d的富集培養(yǎng)，可以得到硝化速率為4.18mg(NH3-N)-g(MLSS)/h和10.1mg(NH4-N)-g(MLSS)/h的硝化細菌培養(yǎng)物在這種富集培養(yǎng)過程中，硝化細菌培養(yǎng)物的污泥色澤和結(jié)構(gòu)、MLSS、SV30、SVI、硝化強度和硝化速率等均出現(xiàn)規(guī)律性變化且隨培養(yǎng)方法不同表現(xiàn)出明顯差異。關(guān)鍵詞：硝化細菌；反硝化細菌；脫氮；富集培養(yǎng)；硝化速率；活性污泥；載體Abstract: In todays world environment pollution is aggravating,especially the water pollution has seriously aff

5、ect Peoples Daily lifeand health. Water pollution is various factors, and ammonia nitrogenpollution in the most extensive and severe. So control of ammonianitrogen content is sewage wastewater treatment in the important content.The basic principle of sewage denitrification is the nitrogen organicwas

6、tewater by microbes function first ammoniation into ammonia,nitrifying bacteria of nitrification, will ammonia oxidation as nitrite,and continue to oxidation as nitrate. Nitrate after denitrifyingbacteria against nitrification into nitrogen links such as compositionand released to the atmosphere, so

7、 as to realize the sewagedenitrification. Is this a nitrification process of a intermediate link,and also an important link. Nitrification refers to the role of ammoniaafter microbial oxidation and the process of nitric acid based, bynitrifying bacteria complete. Nitrifying bacteria is a kind ofphot

8、osynthetic bacteria can fleas, including the nitrifying bacteria andnitrifying bacteria two subsets. Nitrifying bacteria can use YuanTaiinorganic nitrogen compounds are also growing autotrophic, nitrifyingbacteria in the life activities of sewage denitrification plays animportant role. Because of ni

9、trifying bacteria is which can sustainbacterium, the growth rate is slow, therefore nitrification, nitrosationbacteria life activities of sewage denitrification become one of the keysteps. They can effectively reduce the water in ammonia nitrogen basedand nitrogen content, aquaculture and environmen

10、tal protection to havethe important meaning. dressfying bacteria is biological nitration takeoff to play a major role ammonia of microbes, directly influence theeffect and biological nitrification off the efficiency of ammonia.Because nitrifying bacteria, denitrifying bacteria in the sewage anddenit

11、rification of special significance, for this kind of microbe studyis widely concerned about.Ammonia and respectively based nitrosation bacteria and is the onlyenergy denitrifying bacteria. The essential bacteria growth environmentfor it to its large effect on the temperature, pH value and salinityin

12、fluence is relatively minor. The most essential bacteria growthtemperature right for 10 to 38 , 20 higher than when the activityof nitrifying bacteria are higher, but more than 38 digestivefunction will disappear. When the environment temperature less than 20, ammonia transformation can be affected.

13、 Generally, appropriatedenitrifying bacteria and the denitrifying bacteria growth medium pHvalue were 6.0 8.5 and 6.0 8.0. The water DO will affect the goodoxygen, anaerobic microbe proportion, most researchers think theconcentration shall control in DO 1.0 2.0 mg/L, less than 0.5 mg/Lnitrification

14、when significantly weakened. In addition, carbon andnitrogen, basicity on than nitrification and take off all affect theammonia.This experiment used artificial medium enrichment of nitrifyingbacteria cultivation method. The process of cultivation of nitration andenrichment of nitrifying bacteria and

15、 the structure and properties ofchange. The results show that, in 25 to 28 , pH7.5 8.5, D0 2-5mg/L,ammonia nitrogens 100-150 mg/L conditions, after 19 d and 15 denrichment training, can get nitration rate for 4.18 mg (NH3-N)-g (MLSS)/ h and 10.1 mg (NH4-N)-g (MLSS) / h of nitrifying bacteria culture

16、substance. In this enrichment process of cultivation, nitrifyingbacteria culture substance of sludge colour and lustre and structure,MLSS, SV30, SVI, nitrification strength and nitration rate all appear toregular change with different methods and training showed obviousdifference.Key words ：Nitrifyi

17、ng bacteria; Denitrifying bacteria；Denitrification; Enrichment training; Nitration rate; Activated sludge;carrier引 言據(jù)2010年環(huán)境狀況公報顯示，我國環(huán)境總體形勢依然十分嚴峻湖泊（水庫）富營養(yǎng)化問題依然突出，在監(jiān)測營養(yǎng)狀態(tài)的26個湖泊（水庫）中，富營養(yǎng)化狀態(tài)的占42.3水體的富營養(yǎng)化問題主要由水體中的總氮超標所引起由于氮元素污染的危害，脫氮已經(jīng)成為水處理和防止氮素危害的重要一步目前普遍認為，生物脫氮是水處理中防止氮素危害最經(jīng)濟有效的方法之一傳統(tǒng)生物脫氮途徑一般包括硝化和反硝化兩個

18、步驟，即在好氧條件下通過自養(yǎng)硝化菌的作用，將水中氨氮（NH4+-N）轉(zhuǎn)化為硝酸氮（NO3-N）或亞硝酸氮（NO2-N），然后在缺氧或厭氧條件下，利用反硝化菌將硝酸氮和亞硝酸氮還原為氮氣，達到脫氮的目的由于兩個菌的作用條件不同，這兩個過程不能同時發(fā)生，只能序列進行近些年來，不斷有好氧反硝化細菌的分離報道，好氧反硝化現(xiàn)象的出現(xiàn)突破了傳統(tǒng)理論的束縛，使人們對生物脫氮技術(shù)的發(fā)展有了全新的認識已有文獻報道一些好氧反硝化細菌同時具有異養(yǎng)硝化功能，這一發(fā)現(xiàn)為同時硝化反硝化工藝（simultaneousntrification denitrification，SND）發(fā)展奠定了理論基礎(chǔ)因此異養(yǎng)硝化好氧反硝化菌正成為研究的熱點文獻報道的許多菌屬如：Pseudomonasstutzeri,Thiosphaerpantotropha,Alcaligenes fa