外文翻譯---條件和構(gòu)造在pasveer氧化溝中對(duì)硝化和反硝化作用的影響

1、<p>　　CONDITIONS AND MECHANISMS AFFECTING</p><p>　　SIMULTANEOUS NITRIFICATION AND DENITRIFICATION</p><p>　　IN A PASVEER OXIDATION DITCH</p><p><b>　　Abstract</b><

2、/p><p>　　Simultaneous nitrification and denitrification in a Pasveer oxidation ditch was studied.The purpose was to evaluate the performances of both nitrification and denitrificaion in oxidation ditches,and to

3、 pursue some possible approaches to enhance nitrogen removal.Almost complete nitrification was observed under normal conditions,but when DO＜1.0mg/l and /or T＜4℃,nitrification was profoundly affected.Also because of low t

4、emperature,transient nitrite accumulation appeared on two occasions.It was conc</p><p>　　Key words:Nitrification,denitrification,Pasveeroxidation ditch,anoxic zones,flocs,mixed liquor, dilution factor,fibrou

5、s carriers,contacts,contact tank.</p><p>　　NOMENCLATURE</p><p>　　DO:Dissolve oxygen（mg/l）, T:Temperrature（℃）, p.e.:Population equivalent, SS:Suspended solid（mg/l）, MLSS:Mixed liquor suspended so

6、lid（mg/l）, MLVSS:Mixed liquor volatile suspended solids（mg/l）, COD:Chemical oxygen demand（mg/l）, BOD5:5-day biochemical oxygen demand, HRT:Hydraulic retention time（h）, SRT:Solids retention time（days）, Kj-N:Total Kjeldahl

7、 nitrogen（mg N/l）, TN:Total nitrogen（mg/l）, SVI:Sludge volume index（ml/g）, SV%:Specific volume of sludge settlement for 30 min（%）</p><p>　　INTRODUTION</p><p>　　The oxidation ditch process is an

8、economic and efficient technique of biological wastewater-treatment. In controlling eutrophication,oxidation ditch are competitive with other activated-sludge processes. Though the</p><p>　　Pasveer oxidize t

9、he first design speculation of the ditch and can carry on at the same time in diding not hope to make nitric turn respond to turn to respond with anti- nitric, oxidize the special structure of ditch and handle the charac

10、teristics of the process to has already let this become realistic.In fact, it is many to oxidize the ditches existingly to all have these at the same time two kinds of respond.However,the efficiencies of nitrogen removal

11、 differ from place to place.</p><p>　　In the framework of international agreement on reduction of nutrients discharge to the river Rhine and the North sea, Holland government puts forward a new restrict to t

12、he catchment of the liquid waste processing factory again.In new standard, the total nitrogen is must be low in 15 mgs/ l in a water. For this, a concerning carry on </p><p>　　nitric's turn to respond at

13、 the same time in Pasveer oxidize ditch to turns the reaction with anti- nitric of research has already start. This research plan installs for condition and machines that respond synchronously and settle an accommodation

14、, return for increase the nitrogen to do away with the rate to look for the viable path.For this purpose, a study </p><p>　　concerning simultaneous nitrification and denitrification in a Pavsser oxidation di

15、tch was initiated.</p><p>　　The study was intended to determine the conditions and mechanisms affecting simultaneous nitrification and denitrification. The end conclusion think that rise to decide the functi

16、on to lie in the upgrade that oxidizes the ditch existingly to Holland and in China of of applied expansion.</p><p><b>　　METHODS</b></p><p>　　Details of process and construction of t

17、he Pasveer ditch</p><p>　　In the early1960s, a pilot-scale Pasveer oxidation ditch was constructed at TNO Delft in the Netherlands for the research purpose of Dr A.Pasveer. The whole system from a single dit

18、ch way,a aerating spirit turns to brush,a precipitates the pond, a clarifies the pond, a dehydrates the dry building,a dirty water promotes the pump constitute.A flow diagram is shown in Fig.1.</p><p>　　The

19、design volumn of the ditch is 150m3 with an average recirculation length of 68.5m; The horizontal piece of the ditch faces to an is on the bottom 3.6 ms, descending the trapezoid of the bottom 1.2 ms. The spirit turns to

20、 brush to turn round the round for a level steel, diameter with long distinguish for the 0.7m and 1.5m, respectively.The current capacity is about 400 p.e.</p><p>　　The present settler is actually the origi

21、nal thickening tank, which has a circular plan with a diameter of 1.62m and a cone base sloped at 60° to the horizontal. The depths of the cylinder and the cone are 1.55m and 0.80m, repectively.</p><p>

22、　　The grit chamber is cubic with a total volumn of 40m3; a large diameter water wheel in the chamber slowly rotates to prevent SS from settling.</p><p>　　Working conditions</p><p>　　The raw wast

23、ewater came from a well-define sewer district of Delft city; the influent, therefore, consisted only of domestic sewage. The influent quality during the study is summarised in table 1.</p><p>　　During the st

24、udy, the influent flow rate was maintained at about 60m3/day; Under thus a discharge, the water power that clarifies the pond carries for the 29 m3/ day, this capacity and ditches that means the clearness pond matches sm

25、all.</p><p>　　Oxidize the ditch in with MLSS and MLVSS to sediments measure among them; The MLSS scope is generally in 1000~4000 mgs/ l.（ MLSS/MLVSS=0.74） It have no in this operation process to sink the san

26、d to carry on to tidy up usually; When admixture the MLSS of the liquid over 4000 mgs/ l also will eject the ditch directly. The earating brush turns to brush an every minute 80 turn of turn soon underwater movement in 1

27、0~13 cm. Equally again circulating velocity according to dip into the water deep of dis</p><p>　　The sludge loading based on COD was between 0.02 and 0.21 kgCOD/kgMLSS·day. According to usual COD/ BOD5

28、in Holland is 3.0 of ratio, predominate the BOD5 of the dirty mire quantity value be think in the 0.01~0.07 kg/ kgMLSS·Day.This means to oxidize it is very high that SRT in the ditch plant.According to thus an exper

29、ience:SRT was estimated to be between 25 and 50 days,</p><p><b>　　ANAlYSES</b></p><p>　　Influent and effluent qualities and sludge characteristics were analysed daily.Besides the inf

30、luent data summarised in Table1, dailiy analyses included the effluent data in terms of COD, Kj-N, NH4+-N, NO2ˉ-N, NO3-N,SS,pH, and also the mixed liquor data such as MLSS, MLVSS, SVI and DO. The SVI mix with DO etc. A w

31、ater data that the liquid data mean. The sample that enters the water and a waters distinguishes in entrance sink the sand pond and clarify pond.The dirty mire sample adopt direct from m</p><p>　　COD was ana

32、lysed according to a Dutch standard NEN6633. Kj was analysed after destruction with sulphuric acid and potassium sulphate. NH4+-N, NO2--N, NO3—N were analysed according to DIN 38406-5,DIN38405-10 and 38405-D9-2, or a Cuv

33、ette Test deteloped by Longe. SS, MLSS and MLVSS were measured according to the standard methods, 2540B, 2540D and 2540E（A PHA,1990）. The pH and DO were, resoectively, measured with the Microprocessor Meters presented by

34、 WTW（pH 96 and OXI 91）. SVI was measured and calc</p><p>　　RESULT AND DISCUSSION</p><p>　　Mass balance of nitrogen in the ditch</p><p>　　In general, the nitrogen loss in aqueous sys

35、tems can be explained by three pathways: ammonia stripping, assimilation and dissimilation by bacteria. Ammonia Stripping is a minor pathway in biological wastewater-treatment. Free ammonia in water is in equilibrium wit

36、h the ammonium ion. At pH=7.5, the percentages of the NH4+ from are, respectively, 99.6% at 25℃ and 98.3% at ℃4. As a result, ammonia stripping was assumed to be negligible as the pH of the mixed liquor in the ditch was

37、usually below 7.</p><p>　　Assimilation is generally responsible for 25-30% of the nitrogen loss in biological wastewater-treatment. For oxidation ditches, however, waste sludge is quite small and nuisance-fr

38、ee. A long SRT is needed to miniise waste sludge. The longer the SRT, the greater the amount of auto-oxidation and the less the wastesludge. In the case of the Pasveer ditch, the SRT of25-50 days was long enough to reali

39、ze complete auto-oxidation. Therefore, the nitrogen lost in the form of biomass was also assumed to</p><p>　　Excluding ammonia strpping and assimilatin, the nitrogen loss was explained just by dissimilation

40、in the ditch. So the mass balance of nitrogen could be established by nitrification and denitrification were easily calculated, respectively, by influent and effluent Kj-N and TN at the constant flow rate.</p><

41、;p>　　Nitrification</p><p>　　Kj-N concentration in influent and effluent and the efficiencies ofnitrification are plotted in Fig.2. The results show that nitrification was quite complete except for two occ

42、asions. The average efficiency of nitrification of＞90% was obtained.</p><p>　　There were two drops the efficiencies of nitrification, as shown in Fig.2. Theoperational diary indicates that DO and temperature

43、 might be responsible for these two drops as the other environmental factors had no sudden changes. Do just ahead of the aerating brush was measured around 0.8 mg/l on days 130-140; temperature was found below 4℃ on days

44、 230-245.</p><p>　　The Do data were measured at 12 locations around the ditch with the aerating brush used as the first location. At each location, Do was measured at two points, one at 10 cm below the water

45、 surface and the other at the bottom of the ditch. Figure 3 shows the maximum and minimum DO data in the ditch; a typical Do profile around the ditch is shown in Fig.4.</p><p>　　As shown in Fig.3, a Do gradi

46、ent between 0.8 and 1.5 mg/l was maintained under normal conditions. From Fig.4, the Do levels on the surface and at the bottom began to equalize after a distance of about 17 m from the aerating brush（near location B in

47、Fig.1）.</p><p>　　Based on the maximum Do data, the effect of DO on the efficiency of nitrification is shown in Fig.5. When DO＞1.0mg/l, the efficiencies of nitrification reached almost 100%. Although it was r

48、eported that a </p><p>　　DO value of at least 2.0 mg/l was essential to maintain complete nitrification in biological wastewater-treatment, a Do value of 1.0 mg/l or more appeared enough for nitrification in

49、 the Pasveeer ditch. This observation should be attributed to a low sludge loading or a high SRT of the ditch. Stenstrom and Poduska and Stenstrom and Song came to a similarconclusion about the relationshup between SRT a

50、nd DO; they found that the increased SRT allowed nitrification at lower DO.</p><p>　　Temperature in the mixed liquor changed over the seasons; monthly average temperature is summarized is summarized in Table

51、 2. The effect of temperature on the efficiency of nitrification is shoen in Fig.6. The efficiency of nitrification remained constantly high when temperture was over 4℃. Even at 4℃, the efficiency of nitrification still

52、reached over 90%. According to the literature, nitrification should be profoundly influenced by temperature. However, due to high STRs the ditch demonstrated </p><p>　　Below 4℃, atransient nitrite accumulati

53、on in effluent was observed whilst the normal NO2—N approached zero. The nitrote accumulation was observed on two occasions during the study. On these two occasions DO was not a limiting Factor（see Fig.3）. To a large ext

54、ent, temperature was responsible for the phenomena, as shown in Fig.8.</p><p>　　In the process of nitrification, the transformation of ammonia to nitrite has been reported to yield approximately three times

55、more energy than the transformation of nitrite to nitrate. Therefore, three times as much nitrite in step2 must be processed to yield the same energy as in step 1. As a result, nitrite accumulation is not expected under

56、normal conditions.</p><p>　　The effect of temperature on the nitrite accumulation is probably relative to the growth characteristics of Nitrosomonas and Nitrobacter. The nitrite accumulation meant that Nitro

57、bacter was more sensitive than Nitrosomonas to low temperature.</p><p>　　The rate of nitrification and the applied Kj-N loading are potted in Fig.9. Alinear correlation impies that there was a strong capacit

58、y to absorb shock nitrogen loading in the ditch. In other words, there should be a pseudo- maximum value was not reached even under a nitrogen loading of 1.5mg N/g VSS·h.</p><p>　　According to Painter,

59、the rate of ammonia oxidation observed in activated sludge is 0.5-6mg N/g MLSS·h. Based on the ratio of MLSS/MLVSS during the study,the rate ofnitrification in the ditch was 1.4-4.1 mg N/g MLSS·h, which had not

60、 reached its upper limit. For this reason, the efficiency of nitrification in oxidation ditch could be always kept at high levels.</p><p><b>　　中文譯文</b></p><p>　　條件和構(gòu)造在Pasveer氧化溝中對(duì)硝化和

61、反硝化作用的影響</p><p>　　摘要：通過(guò)對(duì)Pasveer氧化溝中的硝化和反硝化作用的研究，達(dá)到了評(píng)估兩種反應(yīng)的效果并尋求了提高去氧率的一些可能的方法。大多數(shù)對(duì)完全硝化反應(yīng)的觀察都是在正常條件進(jìn)行的，但在DO為1.0mg/L和T4時(shí)，硝化反應(yīng)就發(fā)生了深刻的變化。因?yàn)榈蜏?，使得?duì)呈過(guò)渡態(tài)的亞硝酸鹽不斷積累。然而，反硝化反應(yīng)具有多樣性和不穩(wěn)定性?xún)蓚€(gè)特點(diǎn)，在一個(gè)為期將近10個(gè)月的研究中發(fā)現(xiàn)平均的亞硝酸鹽去除率僅為

62、45%。反硝化</p><p>　　作用之所以碰上這種瓶頸主要是缺乏穩(wěn)定的含氧區(qū)和碳混合物。已有一</p><p>　　些建議和方法被提出用來(lái)提高反硝化作用的效率。</p><p>　　關(guān)鍵詞：硝化作用 反硝化作用 Pasveer氧化溝 含氧區(qū) 蓄凝物 混合液 稀釋因子 纖維載體 接觸槽</p><p>　　術(shù)語(yǔ)：DO：溶解氧

63、 T：溫度 p.e：人口當(dāng)量 SS：懸浮物 MLSS：混合液懸浮固體 MLVSS：可揮發(fā)性混合液懸浮固體 COD：化學(xué)需氧量（mg/L） BOD5：5天生物需氧量（mg/L） HRT：水力停留時(shí)間 TN：總含氮量 SVI：沉淀容積指數(shù) SV%：30分鐘沉淀率</p><p><b>　　說(shuō)明：</b></p><p>　　氧化溝過(guò)程是一種經(jīng)濟(jì)有效的生

64、物廢水處理技術(shù)。在控制富營(yíng)養(yǎng)化污染方面，氧化溝法有著不亞于其他處理技術(shù)的競(jìng)爭(zhēng)力。盡管Pasveer氧化溝的最初設(shè)計(jì)構(gòu)想中并沒(méi)有指望使硝化反應(yīng)和反硝化反應(yīng)能夠同時(shí)進(jìn)行，但氧化溝特殊的構(gòu)造和處理過(guò)程的特點(diǎn)已讓這成為現(xiàn)實(shí)。事實(shí)上，許多現(xiàn)存的氧化溝都同時(shí)具有著這兩種反應(yīng)。然而，氮去除率卻因地而異。</p><p>　　在一項(xiàng)關(guān)于減少對(duì)萊茵河與北冰洋的廢水氮排放上午國(guó)際協(xié)議框架中，荷蘭政府對(duì)廢水處理廠的排水又提出了一項(xiàng)新的

65、限制。在新標(biāo)準(zhǔn)中，</p><p>　　出水中總氮必須低于15mg/L。更加嚴(yán)格的出水限制標(biāo)準(zhǔn)意味著未來(lái)幾年來(lái)有大量的污水廠需要強(qiáng)化升級(jí)。為此，一項(xiàng)關(guān)于在Pasveer氧化溝中同時(shí)進(jìn)行硝化反應(yīng)和反硝化反應(yīng)的研究已經(jīng)啟動(dòng)。此研究計(jì)劃為同步反應(yīng)定出合適的條件和機(jī)械配置，還為增加氮去除率尋找可行的途徑。最終結(jié)論認(rèn)為，起決定作用的在于對(duì)荷蘭現(xiàn)存的氧化溝的升級(jí)及在中國(guó)的的應(yīng)用推廣。</p><p>

66、<b>　　技術(shù)：</b></p><p>　　Pasveer氧化溝的運(yùn)行細(xì)節(jié)及構(gòu)造</p><p>　　早在20世紀(jì)70年代，一個(gè)探索性的為研究而建立的Pavseer氧化溝誕生了。整個(gè)系統(tǒng)由一條單溝道，一個(gè)曝氣轉(zhuǎn)刷，一個(gè)沉淀池，一個(gè)澄清池，一個(gè)脫水干燥房，一個(gè)污水提升泵所組成。流量數(shù)據(jù)已在圖1中顯示。</p><p>　　溝的設(shè)計(jì)容量為平均每

67、68.5m的循環(huán)中150m3；溝深為1m。溝的橫截面為一個(gè)上底3.6m，下底1.2m的梯形。曝氣轉(zhuǎn)刷為一個(gè)水平鋼構(gòu)回轉(zhuǎn)輪，直徑與長(zhǎng)分別為0.7m和1.5m。溝原先的設(shè)計(jì)容積大約為400p.e.。</p><p>　　當(dāng)前的澄清池實(shí)際上是原來(lái)的貯水池的加厚版本，它是由一個(gè)直徑1.62m的環(huán)狀柱體和一個(gè)與地面成60度的傾斜角的圓錐組成。</p><p>　　沉砂池是一個(gè)容積40立方米的立方體；

68、其中的大直徑水輪通過(guò)緩慢轉(zhuǎn)動(dòng)來(lái)阻止懸浮物的沉降。</p><p><b>　　工作條件：</b></p><p>　　未經(jīng)處理的廢水通過(guò)一條專(zhuān)門(mén)的污水管道從城市中收集而來(lái)，因此，支流僅僅由地下管道組成。支流水質(zhì)詳見(jiàn)表1。</p><p>　　在這個(gè)研究中，支流流量維持在60m3/天，相應(yīng)的HRT為60小時(shí)左右。在這樣一個(gè)流量下，澄清池的水力負(fù)荷

69、為29m3/天，這意味著澄清池的容量與溝渠匹配起來(lái)過(guò)小。</p><p>　　氧化溝中以MLSS和MLVSS來(lái)衡量其中的沉淀物；MLSS的范圍一般在1000~4000mg/l（MLSS/MLVSS=0.74）。這個(gè)操作過(guò)程中沒(méi)有對(duì)沉砂渣進(jìn)行日常清理；當(dāng)混合液的MLSS超過(guò)4000mg/l時(shí)也會(huì)直接排出溝外。曝氣轉(zhuǎn)刷一每分鐘80轉(zhuǎn)的轉(zhuǎn)速在10~13cm的水下運(yùn)行。平均再循環(huán)速率依據(jù)浸入水深的不同而定，混合液沿溝的速

70、率為0.30~0.37m/s。</p><p>　　主導(dǎo)污泥量的COD值在0.02和0.21/kgCOD/kgMLSS之間。根據(jù)荷蘭通常的COD/BOD5為3.0的比率，主導(dǎo)污泥量的BOD5值被認(rèn)為在0.01~0.07kg/kgMLSS·day。這意味著氧化溝內(nèi)的SRT植是相當(dāng)高的?；?lt;/p><p>　　于這樣一個(gè)經(jīng)驗(yàn)：當(dāng)污泥產(chǎn)量為30~40gMLSS/day時(shí)，SRT估計(jì)在2

71、5~50天之間。</p><p><b>　　分析：</b></p><p>　　日常的分析對(duì)象為進(jìn)出水水質(zhì)和污泥的特性，除了表1摘要的進(jìn)水資料外，分析還包括以COD，Kj-N，NH4+-N，NO2ˉ-N，NO3ˉ-N，SS，PH以及MLSS，MLVSS，SVI和DO等混合液數(shù)據(jù)表示的出水資料。進(jìn)水與出水的采樣分別在入口處的沉砂池與澄清池中。污泥采樣采取直接從溝中取樣

72、的方法。這些分析操作需要一個(gè)星期進(jìn)行兩次。</p><p>　　COD的分析是根據(jù)荷蘭的NEN6633標(biāo)準(zhǔn)。Kj-N的分析在脫除硫酸和硫酸鹽鉀之后進(jìn)行。NH4+-N，NO2-N，NO3—N的分析的根據(jù)DIN38406-5、DINI38405-10和38405-D9-2,或者是郎爵爾發(fā)明的試管測(cè)試。SS，MLSS和MLVSS的測(cè)量是根據(jù)標(biāo)準(zhǔn)技術(shù)，分別有2540B，2540D和2540E。PH和DO都用計(jì)算機(jī)技術(shù)分析

73、。SIV的測(cè)量和計(jì)算是通過(guò)SV%和MLSS來(lái)實(shí)現(xiàn)的。</p><p><b>　　結(jié)果與討論</b></p><p>　　氧化溝內(nèi)混合物的氮平衡</p><p>　　通常，氮在一個(gè)水環(huán)境系統(tǒng)中的損失有三種解釋?zhuān)喊钡娜コ约凹?xì)菌的同化和異化。在一個(gè)生物廢水處理系統(tǒng)內(nèi)氨的去除只占很小的一部分。自由氨在水中與氨離子之間存在著一個(gè)平衡。當(dāng)PH=7.5

74、，溫度為25℃時(shí)氨離子形式的百分?jǐn)?shù)為99.9%，溫度為4℃時(shí)為98.3%。因此，當(dāng)氧化溝內(nèi)混合液的PH植低于7.5時(shí)氨的去除是幾乎可以忽略的。</p><p>　　在生物廢水處理系統(tǒng)中經(jīng)同化作用除去的氨占的比例大約為25-30%。然而對(duì)氧化溝來(lái)說(shuō)廢水沉淀物是相當(dāng)少的（理論上為零）。一個(gè)長(zhǎng)時(shí)間的STR過(guò)程對(duì)廢水沉淀物的最小化來(lái)說(shuō)是必需的。SRT過(guò)程越長(zhǎng)，自動(dòng)氧化進(jìn)行的越充分，廢水沉淀物也就越少。以Pasveer氧化

75、溝為例，20-50天的STR過(guò)程對(duì)實(shí)現(xiàn)完全的氧化過(guò)程已經(jīng)足夠了。因此，以生物量的形式損失的氮可以被認(rèn)為是微不足道的。</p><p>　　除了氨的去除和同化外，氨的減少只與溝內(nèi)的異化作用有關(guān)。因此氮元素的平衡可以通過(guò)消化作用和反消化作用來(lái)建立。只要根據(jù)正常流量下流入和流出的Kj-N和TN值，硝化作用和反硝化作用的效率能夠很容易的計(jì)算出來(lái)。</p><p><b>　　硝化反應(yīng)&l

76、t;/b></p><p>　　入水和出水的Kj-N的濃度與硝化反應(yīng)的效率已在圖2中列出。這結(jié)果說(shuō)明了在兩種情況下硝化作用進(jìn)行的相當(dāng)充分。平均的硝化反應(yīng)效率可達(dá)90%以上。</p><p>　　根據(jù)圖2可以看出，這存在著兩個(gè)反應(yīng)效率的下降點(diǎn)。這個(gè)操作日志暗示著DO和溫度可能與這兩個(gè)下降點(diǎn)有關(guān)，因?yàn)槠渌沫h(huán)境因素沒(méi)有如此突然的變化。據(jù)測(cè)量，曝氣轉(zhuǎn)刷前的溶解氧含量在130-140天為&l

77、t;/p><p>　　0.8mg/l；溫度在230-245天是在40℃以下。</p><p>　　DO值是在12個(gè)不同位置測(cè)量的，而在曝氣刷上為第一位置。在每一位置的DO值測(cè)量在兩個(gè)不同的點(diǎn)。一個(gè)在水面10cm下，另一個(gè)在氧化溝溝底。圖3說(shuō)明了溝中溶解氧的最大值和最小值（分別位于曝氣刷前后）；圖4顯示了一個(gè)氧化溝中典型的溶解曲線。</p><p>　　由圖三顯示溶解氧曲

78、線在0.8與1.5mg/l時(shí)是維持在正常的條件下。由圖4可以看出，在曝氣轉(zhuǎn)刷17m的地方表面及底部的溶解氧開(kāi)始均勻混合。</p><p>　　根據(jù)溶解氧的最大值，DO對(duì)硝化反應(yīng)的影響圖5列出。當(dāng)DO＞1.0mg/l時(shí)，硝化反應(yīng)的效率幾乎達(dá)到100%。盡管理論上DO值至少要2.0mg/l才足以維持硝化反應(yīng)的完全進(jìn)行，但在Passver氧化溝中DO值為1.0mg/l以上就足夠了。這歸因于溝中的低污泥負(fù)荷或高SRT。多

79、位科學(xué)家最后對(duì)STR與DO之間的關(guān)系得出了相似的結(jié)論；他們認(rèn)為STR值的增加使得硝化反應(yīng)在低DO下進(jìn)行成為可能。</p><p>　　混合液的溫度隨著季節(jié)的變化而變化；月平均溫度已在表2中列出。溫度對(duì)硝化反應(yīng)效率的影響也由圖6顯示。硝化反應(yīng)效率在4℃以上時(shí)維持在一個(gè)相當(dāng)高的水平。就算在4℃時(shí)，硝化反應(yīng)效率仍然可達(dá)90%以上。根據(jù)文獻(xiàn)資料反應(yīng)，溫度對(duì)硝化反應(yīng)有著強(qiáng)烈的影響。然而，由于氧化溝中的高SRT值證明了低溫下

80、也能進(jìn)行劇烈的硝化反應(yīng)。</p><p>　　在4℃以下時(shí)，當(dāng)出水口出的普通氨氮值達(dá)到一定值是卻有一過(guò)渡態(tài)的亞硝酸鹽持續(xù)積累。在這個(gè)研究中的亞硝酸鹽積累被認(rèn)為有兩個(gè)原因。這兩個(gè)原因中的DO值并不是一個(gè)限制因素。在很大程度上來(lái)說(shuō)，溫度對(duì)這種現(xiàn)象的形成有著重要聯(lián)系，就如圖8所示那樣。</p><p>　　在硝化反應(yīng)這個(gè)過(guò)程中，據(jù)研究發(fā)現(xiàn)把氨轉(zhuǎn)化為亞硝酸鹽所需的能量為該逆過(guò)程所需能量的3倍。因此

81、，步驟二中3倍數(shù)量亞硝酸鹽反應(yīng)所產(chǎn)出的能量與步驟一中的能量值鹽積累的影響很可能與相應(yīng)的硝化細(xì)菌和亞硝化細(xì)菌的增長(zhǎng)有關(guān)。亞硝酸鹽的增長(zhǎng)意味著亞硝酸相等。由此可知，亞硝酸鹽的積累并非偶然。</p><p>　　溫度對(duì)亞硝酸菌比硝酸菌在低溫下更加活躍。</p><p>　　消化反應(yīng)率與總有機(jī)氮的關(guān)系已在圖9中繪出，成直線形的比例關(guān)系暗示著存在一個(gè)很強(qiáng)的約束相關(guān)性。換句話(huà)說(shuō)，硝化反應(yīng)存在著一個(gè)最大