王文林,劉 筱,韓宇捷,杜 薇,劉 波,曾杰亮,童 儀,高 巖,關(guān) 雷,范軍旗,李文靜,何 斐
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規(guī)模化豬場機械通風水沖糞式欄舍夏季氨日排放特征
王文林1,劉 筱2,韓宇捷2,杜 薇1,劉 波2※,曾杰亮2,童 儀2,高 巖2,關(guān) 雷2,范軍旗2,李文靜1,何 斐1
(1. 環(huán)境保護部南京環(huán)境科學研究所,南京 210042; 2. 南通大學地理科學學院,南通 226007)
選取長三角地區(qū)典型機械通風水沖糞模式養(yǎng)豬場,針對不同生長階段的肥豬欄舍和不同類型的母豬欄舍排放口氨排放進行同時監(jiān)測(其中,育肥豬按質(zhì)量分保育(<24 kg)、育肥-Ⅰ(24~60 kg)、育肥-Ⅱ(60~120 kg)3個階段,母豬分為妊娠豬與分娩豬2種類型),估算各欄舍氨排放通量,分析各欄舍氨排放特征,探討各生長階段對氨排放貢獻。研究結(jié)果表明,保育、育肥-Ⅰ、育肥-Ⅱ、妊娠、分娩欄舍氨質(zhì)量濃度分別為(0.97±0.40)、(3.37±0.70)、(5.45±2.30)、(2.19±1.06)、(1.44±0.48)mg/m3;各欄舍氨排放具有顯著的日變化過程,早晨氨排放呈波動增大趨勢,午后開始降低,至夜間保持低值排放;小時氨排放速率與溫度呈極顯著正相關(guān),與濕度呈顯著負相關(guān);各生長階段氨排放存在差異,保育、育肥-Ⅰ、育肥-Ⅱ、妊娠、分娩欄舍日排放速率分別為0.85、6.53、8.20、10.39和13.86 g/(頭·d);保育、育肥-Ⅰ和育肥-Ⅱ階段對肥豬氨排放的貢獻率分別為3.64%、26.11%和70.25%,妊娠豬與分娩豬對母豬氨的貢獻率分別為75.32%和24.68%,母豬的氨排放速率是肥豬的1.87倍。
氨;排放控制;污染;規(guī)?;B(yǎng)豬場;水沖糞
氨(NH3)是大氣中的堿性氣體,其與二氧化硫、氮氧化物迅速形成細顆粒物(PM2.5)[1-3],是重污染天氣二次無機顆粒物爆發(fā)式增長的重要前體物[4],對霧霾的形成和大氣污染有著重要影響。畜禽養(yǎng)殖是大氣氨的主要排放源,研究表明中國畜禽養(yǎng)殖氨排放量占總排放量54.06%。中國作為養(yǎng)豬大國,由于過于追求肉產(chǎn)量,在豬日糧中加入過高的蛋白質(zhì),導致糞便中產(chǎn)生過高的氨排放,中國養(yǎng)豬業(yè)氨排放總量遠遠高于歐美國家[5],其氨排放占畜禽養(yǎng)殖業(yè)氨排放量之首[6]。因此,開展典型規(guī)?;i場氨排放特征研究,進而提出氨排放系數(shù),核算區(qū)域養(yǎng)豬的氨排放量,對于區(qū)域PM2.5粒子源解析,闡明典型農(nóng)業(yè)源氨排放污染現(xiàn)狀、控制大氣顆粒物污染、改善區(qū)域環(huán)境空氣質(zhì)量都有著非常重要的意義。
國外針對豬舍氨排放研究起步較早,開發(fā)了面向開放性欄舍的通風量監(jiān)測方法[7-9],著重探討了欄舍的通風方式對于氨排放的影響[10-11],分析了不同清糞方式下欄舍氨排放特征[12-14]。中國研究尚處于起步階段,國內(nèi)學者對開放性豬舍不同季節(jié)氨排放通量進行了監(jiān)測與估算[15-16],初步探討了欄舍地板結(jié)構(gòu)對欄舍氨排放的影響[17]。對欄舍氨排放與溫度、濕度、通風量等主要影響因子還缺乏系統(tǒng)研究。此外,分析同一時間段內(nèi)不同生長階段育肥豬以及母豬的氨排放特征,辨明各生長階段肥豬、不同類型母豬對氨排放貢獻,為提出科學可靠的生豬氨排放系數(shù)提供科學依據(jù),對準確測算區(qū)域養(yǎng)豬氨排放量具有重要意義。但是,目前還無針對同一時間內(nèi)不同生長階段肥豬與母豬的氨排放特征的系統(tǒng)研究,對于不同生長階段肥豬、不同類型母豬對氨排放貢獻,以及肥豬與母豬氨排放之間的相互關(guān)系尚不清楚。
本研究選取典型規(guī)?;i場,監(jiān)測不同生長階段肥豬與母豬欄舍氨排放濃度,核算不同生長階段育肥豬與母豬的排放速率,探究規(guī)?;B(yǎng)豬場欄舍氨排放特征,辨析氨排放重要影響因素,探討生長階段肥豬、不同類型母豬對氨排放貢獻,以及肥豬與母豬氨排放之間的相互關(guān)系,以期為區(qū)域畜禽養(yǎng)殖氨排放核算提供技術(shù)支撐。
南通市2015年生豬、家禽畜禽養(yǎng)殖量在長三角16個城市中均位居首位。如皋市是南通下屬市縣中的養(yǎng)殖大市,位于長江中下游里下河流域,2015年底,如皋市全市全年生豬飼養(yǎng)量203.47萬頭,生豬存欄量68.56萬頭,家禽飼養(yǎng)量3 636.07萬羽,家禽存欄量1126.68萬羽、奶牛存欄量0.13萬頭,生豬、家禽和奶牛的規(guī)模養(yǎng)殖占比分別達90.21%、95.78%和91%[18]。
選取的豬場位于如皋市搬經(jīng)鎮(zhèn)嚴鮑村,該豬場為江蘇省畜牧生態(tài)健康養(yǎng)殖示范基地,母豬存欄600頭,肥豬年出欄15 000頭左右?,F(xiàn)占地面積7.56 hm2,建筑面積12 000 m2,養(yǎng)殖場平面圖見圖1。欄舍采用智能化母豬飼喂站、全自動喂料線及全自動化通風、采暖系統(tǒng),地面為水泥實心地板,采用人工水沖糞;糞水通過地下管道集中到集糞池提升至沼氣發(fā)酵池進行沼氣發(fā)電。沼液、沼渣返回農(nóng)田作有機肥料。欄舍為全封閉式,舍內(nèi)設(shè)有溫度探頭,進行溫控,當舍內(nèi)達到設(shè)定溫度以上時,欄舍一側(cè)風機排風扇(窗)開啟,舍外新鮮空氣由欄舍另一側(cè)通風窗(夏季開啟濕簾)進入,此時舍內(nèi)廢氣由風機排風扇(窗)排出,當舍內(nèi)溫度回落到設(shè)定溫度以下,風機排風扇(窗)關(guān)閉,不同季節(jié)開啟的排風扇個數(shù)不同。排風起到調(diào)節(jié)溫度及降低舍內(nèi)氨氣等其他氣體濃度的作用,養(yǎng)殖與欄舍概況見表1。
表1 研究豬場養(yǎng)殖與欄舍概況
在不同類型的欄舍進風口和出風口設(shè)置采樣點(見圖1),其中進風口采樣點位于濕簾中心位置,出風口采樣點位于每個開啟的排風扇中心點偏上(經(jīng)前期監(jiān)測此位置能代表排風口的平均速率),采樣點與窗口平面的水平距離為10 cm。同時設(shè)置背景采樣點,在廠區(qū)內(nèi)常年盛行風向上風向的空曠地帶(半徑15 m內(nèi)無欄舍和糞污處理設(shè)施),采樣點高為1.5 m(圖1)。
圖1 養(yǎng)豬場平面與監(jiān)測點布設(shè)示意圖
運用便攜式氨氣檢測儀(smart pro 10,監(jiān)測量程為0~100×10?6,分辨率為0.01×10?6,傳感器為瑞士MEMBRAPOR-CR50,檢測精度為±2%F·S)連續(xù)測定進風口、排放口、背景點氨濃度,連續(xù)監(jiān)測72 h,每分鐘記錄并存儲1次數(shù)據(jù),測定前氣體檢測儀用標準氣體進行標定校正。使用便攜氣象站(美國Kestrel 5000)同步測定排風口排風速率,每分鐘記錄并存儲1次數(shù)據(jù)。在各采樣點通過便攜式氣象站同步測定氣象要素(溫度、氣壓、濕度、風速)每1分鐘記錄并存儲1次數(shù)據(jù)。監(jiān)測于2017年7月2日至4日開展,連續(xù)監(jiān)測3 d。
1.3.1 通風量
式中V為每小時欄舍通風量,m3/h;V為排風口每小時平均排風速率,m/s;為排風口總面積,m2;為排風口每小時累計排風時長,min/h;為采樣點每小時平均溫度,K;0為標準狀況下氣體的溫度,273 K;為采樣點每小時平均氣壓,kPa;0為標準狀況下氣體的壓力,101.3 kPa。
1.3.2 氨排放量
式中a為每小時氨排放量,mg/h;in,out分別為進,排風口氨氣小時平均濃度,mg/m3。
1.3.3 氨排放速率
式中為日排放速率,g/(頭·d);為欄舍中畜禽個體數(shù)。
監(jiān)測期間欄舍排風口和背景監(jiān)測點氨平均排放濃度、平均通風速率、平均溫度、平均濕度見表2。從溫度來看,各欄舍排風口的平均溫度在26.2~27.4 ℃之間,要高于背景平均溫度的25.1 ℃,這主要與欄舍內(nèi)豬自身散熱有關(guān)。從濕度來看,除保育欄舍外其他欄舍濕度要高于背景值,其中,分娩、育肥-Ⅱ,妊娠欄舍排風口平均濕度分別達到98.4%、93.93%和91.3%。濕度的升高主要受濕簾增濕和水沖清糞增濕的影響。各欄舍的通風速率與所開啟的排風扇大小、數(shù)量及通風時間有關(guān),妊娠欄舍、育肥-Ⅱ欄舍由于所養(yǎng)豬只個體質(zhì)量大且數(shù)量多,降溫需求高,通風速率大,平均通風速率分別達到362.41和355.25 m3/min。
背景點氨平均質(zhì)量濃度為0.2mg/m3,各欄舍排放口氨平均排放質(zhì)量濃度在0.97~5.45 mg/m3之間,顯著高于背景值。從肥豬欄舍來看,育肥-Ⅱ欄舍排風口氨平均排放質(zhì)量濃度最大,平均值為5.45mg/m3,最大值達到11.78 mg/m3;其次是育肥-Ⅰ欄舍,平均值為3.37 mg/m3,最大值達到4.72 mg/m3;保育欄舍排風口氨排放平均質(zhì)量濃度最低,為0.97mg/m3,分別為育肥-Ⅱ和育肥-Ⅰ欄舍的17.8%和28.8%。從母豬欄舍來看,妊娠欄舍排風口氨排放平均濃度要高于分娩欄舍,前者是后者的1.52倍。
表2 欄舍排風口和背景點的氨平均濃度、通風速率、平均溫度與平均濕度
通過分析各欄舍排放氨濃度日變化過程(見圖2)發(fā)現(xiàn),各欄舍排放口氨濃度存在明顯的日變化過程,大致表現(xiàn)為早晨氨濃度開始波動上升,至午后開始波動降低,夜間氨濃度保持低值且波動不大。各欄舍排放口氨濃度最大值均出現(xiàn)在上午06:00~08:00左右,與該時段欄舍清糞以及豬晨起后的活動有關(guān),育肥-Ⅱ欄舍由于養(yǎng)殖量和豬質(zhì)量較大,這一過程尤為明顯;最小值出現(xiàn)在夜間,這是由于夜間糞污人為擾動,同時豬自身活動較少。育肥-Ⅱ欄舍由于養(yǎng)殖數(shù)量大,個體質(zhì)量大,全天排放口氨的濃度要高于其他欄舍,同時受清糞、飼喂擾動后的波動要大于其他欄舍。保育欄舍全天各時段排放口氨濃度要基本小于其他欄舍,這與舍內(nèi)所飼養(yǎng)豬的生長日齡較短、質(zhì)量輕、進食量少有關(guān)。在母豬欄舍中,妊娠欄舍白天排放口氨濃度要高于分娩欄舍,妊娠欄舍母豬數(shù)量多有關(guān),而二者在夜間氨濃度差異不大。通過各欄舍氨排放濃度的相關(guān)性分析發(fā)現(xiàn),各欄舍排放口氨濃度相互呈極顯著正相關(guān)(見表3),表明各欄舍排放口氨濃度具有相似的日變化趨勢。
注:圖中數(shù)據(jù)為3日同時刻平均值。
表3 各欄舍排風口每20 min氨濃度的相關(guān)關(guān)系(Pearson系數(shù))
注:**表示極顯著相關(guān)(<0.01)。
Note: ** indicates extremely significant correlation (<0.01).
2.2.1 小時排放速率
各欄舍每小時單位畜禽氨排放量(小時排放速率)日變化過程見圖3。由圖3可知,欄舍每小時單位畜禽氨排放量具有顯著的日變化過程,與欄舍氨排放濃度變化趨勢相似,即早晨氨排放開始波動增大,午后開始降低,至夜間保持低值排放。白天受到清糞、飼喂活動的擾動以及豬自身活動的影響,氨排放出現(xiàn)波動峰值。其中,清糞過程對氨排放影響較大,肥豬各欄舍氨排放峰值均出現(xiàn)在清糞時間段(上午06:00-08:00)。保育、育肥-Ⅰ、育肥-Ⅱ每日最大小時氨排放速率平均值分別為77.4、349.2、715.9 mg/(h·頭),育肥-Ⅱ豬分別是育肥-Ⅰ豬、保育豬的2.05倍和9.25倍。夜間豬處于睡眠狀態(tài),基本無人為擾動,20:00至凌晨04:00保持低值排放,保育、育肥-Ⅰ、育肥-Ⅱ每日最小氨排放速率平均值分別為16.0、192.3、153.4 mg/(h·頭)。保育、育肥-Ⅰ、育肥-Ⅱ欄舍日均排放量別為253.70、1 174.69和2 789.07 g/d,育肥-Ⅱ欄舍分別是育肥-Ⅰ欄舍、保育欄舍2.37倍和10.99倍。母豬欄舍氨排放峰值均出現(xiàn)上午07:00時,妊娠和分娩豬舍每日最大小時排放速率平均值分別為833.8和1 163.9 mg/(h·頭)。從排放總量上來看,妊娠和分娩欄舍日均排放量別為1 703.20和360.40 g/d。分娩欄舍要小于妊娠欄舍,主要是由于分娩欄舍僅有26頭母豬,新出生仔豬體質(zhì)量小,以飲用母乳為食,氨排放很少。
注:圖中數(shù)據(jù)為3日同時段釋放速率平均值。
2.2.2 日排放速率
根據(jù)各類型豬氨排放速率分別計算各類型豬的日排放速率。各生長階段肥豬的每天排放速率分別為0.85(保育)、6.53(育肥-Ⅰ)和8.20 g/(頭·d)(育肥-Ⅱ),隨著個體質(zhì)量增加排放量也逐漸增大,個體質(zhì)量由10 kg增加到85 kg,單位個體肥豬的氨日排放量相應增大了8.64倍。妊娠豬和分娩豬的日排放速率分別為10.39和13.86 g/(頭·d),分娩豬是妊娠豬的1.33倍。
欄舍氨排放受多種因素的共同影響。豬舍內(nèi)糞、尿是舍內(nèi)氨的主要來源,豬只自身活動也會產(chǎn)生一定量的氨[19-21]。豬糞便中的氨氮主要來源于飼料中蛋白質(zhì)在豬消化道中分解產(chǎn)生的氨基酸[22],飼料中的粗纖維比例也對糞便中氨排放存在影響[23-24]。此外,飼料進食量會決定豬的糞尿排泄量。隨著個體生長,單位個體的進食量也在增加,導致糞尿排泄量增多,進而增加氨排放[25]。育肥-Ⅱ階段的肥豬以及母豬氨排放量較大與進食量大有關(guān)(圖3)。清糞過程中導致的糞尿擾動會增大氨釋放,在每天糞便清理時間造成糞尿翻動,飼喂時間欄舍內(nèi)豬的活動強度增大,導致出現(xiàn)氨排放峰值(圖3)。
通過分析各欄舍排放口氨小時排放速率與溫度、濕度相關(guān)性發(fā)現(xiàn),氨排放速率與溫度呈極顯著正相關(guān)(圖4),與濕度呈顯著負相關(guān)(圖5),這與相關(guān)研究結(jié)果一致[26]。進一步對欄舍氨小時排放速率與排風口溫度、濕度的響應關(guān)系進行綜合分析,通過線性回歸分析發(fā)現(xiàn)欄舍氨排放日變化過程與排放口的溫度和濕度的日變化過程存在很好相關(guān)關(guān)系,即一定溫濕度范圍內(nèi),氨排放速率與溫、濕度響應關(guān)系顯著,結(jié)果見表4。表明溫度、濕度是影響?zhàn)B殖場欄舍氨排放的重要因素,在溫度高、濕度低季節(jié)氨排放量會增大,反之則減小。這主要由于較高的溫度能提高脲酶活性,促進糞便中含氮物質(zhì)分解釋放出氨[27],則在一定的通風條件下欄舍會向環(huán)境中排放更多的氨。此外,由于氨的水溶性較大,濕度增大會降低空氣環(huán)境中氨濃度[27]清糞方式?jīng)Q定了糞、尿在舍內(nèi)的存積時間及混合程度,以及糞尿受擾動的程度,進而會影響欄舍氨排放[19,28]。水沖糞相比干清糞,糞便擾動相對較小,加之水沖增加濕度,一定程度上會減少氨的排放。以育肥-Ⅱ階段為例,本研究獲得的日氨排放速率為8.20 g/(頭·d),相同豬只質(zhì)量、機械通風、干清糞模式欄舍夏季氨排放速率為11.89 g/(頭·d)[6],水沖糞模式要比干清糞模式小31.03%(表5)。對比育肥-Ⅰ階段和妊娠豬相關(guān)研究結(jié)果發(fā)現(xiàn),本研究的水沖糞模式下的日氨排放速率相比于干清糞模式也具有相同的結(jié)果(表5)。水泡糞雖減少了清糞對糞尿的擾動,但糞尿在欄舍中存儲時間較長,糞尿會持續(xù)釋放氨進而增加欄舍的釋放量。以分娩豬為例,本研究水沖糞模式的氨日排放速率為13.86 g/(頭·d),相比于水泡糞模式的19.26 g/(頭·d),為后者的71.96%。
圖4 氨排放速率與溫度相關(guān)關(guān)系
圖5 氨排放速率與濕度相關(guān)關(guān)系
表4 氨排放速率與溫度、濕度響應關(guān)系
注:1為溫度,℃;2為濕度,%;為氨排放速率,mg·(h·頭)-1。
Note:1indicates temperature, ℃;2indicates humidity, %;indicates ammonia emission rate, mg·(h·頭)-1).
欄舍通風方式?jīng)Q定了欄舍通風量,對欄舍產(chǎn)生的氨氣等污染氣體排放量有直接作用[29-30]。此外,欄舍通風方式會影響豬舍的溫度、濕度,進而影響欄舍氨排放[31]。機械通風欄舍通常根據(jù)舍內(nèi)溫度設(shè)定排風扇開關(guān)頻率與排風周期。由于夏季溫度較高,排風扇盡量開啟以維持舍內(nèi)溫度不宜過高,因而夏季通風量較大。從理論上講,夏季相同清糞模式下機械通風欄舍相對于通量小的自然通風欄舍的氨排放量有增大的風險。陳園等[6]研究的干清糞模式機械通風欄舍的氨排放速率要大于相同清糞模式自然通風欄舍[32]氨排放速率(表5)。一般機械通風欄舍都配置濕簾,若運行良好在通風降溫的同時可最大程度的增大欄舍濕度,進而通過降溫、增濕來減少空氣環(huán)境中的氨氣濃度。本研究采用濕簾降溫和機械通風模式,并采用水沖糞方式會進一步加大欄舍環(huán)境濕度,會減少欄舍內(nèi)氨的產(chǎn)生進而會降低氨排放量。這可能是本研究氨排放速率小于通風模式欄舍氨排放的主要原因。
表5 國內(nèi)外相關(guān)研究對比情況
根據(jù)肥豬的各生長階段的養(yǎng)殖周期天數(shù)(表1),根據(jù)各階段實測日排放速率核算出肥豬整個生長周期的氨排放量,進而獲得肥豬氨日排放速率為5.94 g/(頭·d)。保育、育肥-Ⅰ和育肥-Ⅱ階段對肥豬氨排放的貢獻率分別為3.64%、26.11%和70.25%(圖6a)。同樣,根據(jù)妊娠豬和分娩豬養(yǎng)殖周期天數(shù)和實測氨日排放速率核算出母豬整體日排放速率為11.07 g/(頭·d),妊娠豬與分娩豬對母豬氨排放的貢獻率分別為75.32%和24.68%(圖6b)。母豬的排放速率是肥豬的1.87倍。
各生長階段肥豬與不同類型母豬由于進食量、日常活動、糞尿排泄量等生理過程不同,導致氨排放量存在明顯差異。從生豬養(yǎng)殖實際來看,同一時間段內(nèi)各個生長階段的肥豬與母豬是同時進行養(yǎng)殖。那么,準確評估各生長階段肥豬、不同類型母豬對氨排放貢獻程度,對提出科學可靠的生豬氨排放系數(shù),進而構(gòu)建高精度、動態(tài)的區(qū)域生豬氨排放清單更有實際意義。應結(jié)合日齡、糞及尿的排放量,開展全年為周期的系統(tǒng)研究。
a. 肥豬
a. Fattening pig
b. 母豬
1)各欄舍氨排放濃度存在顯著差異,保育、育肥-Ⅰ、育肥-Ⅱ、妊娠、分娩欄舍氨質(zhì)量濃度分別為(0.97±0.40)、(3.37±0.70)、(5.45±2.30)、(2.19±1.06)和(1.44±0.48) mg/m3。
2)各欄舍氨排放具有顯著的日變化過程,早晨氨排放開始波動增大,午后開始降低,至夜間保持低值排放;各欄舍受到清糞與豬只自身活動影響在早晨06:00-08:00出現(xiàn)峰值,保育、育肥-Ⅰ、育肥-Ⅱ、妊娠和分娩欄舍每日最大小時氨排放速率分別為77.4、349.2、715.9、833.8和1 163.9 mg/(h·頭)。
3)飼喂、清糞等人為擾動會增加欄舍的氨排放,小時氨排放速率與溫度呈極顯著正相關(guān),與濕度呈顯著負相關(guān)。
4)保育、育肥-Ⅰ、育肥-Ⅱ、妊娠、分娩欄舍日排放速率分別為0.85、6.53、8.20、10.39和13.86 g/(頭·d);經(jīng)核算肥豬和和母豬的氨日排放速率分別為5.94和11.07 g/(頭·d);保育、育肥-Ⅰ和育肥-Ⅱ階段對肥豬氨排放的貢獻率分別為3.64%、26.11%和70.25%;妊娠豬與分娩豬對母豬氨排放的貢獻率分別為75.32%和24.68%;母豬的氨排速率是育肥豬的1.87倍。
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Daily emission characteristics of ammonia from typical industrial pig farm with manure cleaning by rising water in summer
Wang Wenlin1, Liu Xiao2, Han Yujie2, Du Wei1, Liu Bo2※, Zeng Jieliang2, Tong Yi2, Gao Yan2, Guan Lei2, Fan Junqi2, Li Wenjing1, He Fei1
(1.210042; 2.226007,)
Ammonia (NH3), as the only reactive alkaline gas, plays a crucial role in the neutralization of atmospheric sulfuric or nitric acid to generate ammonium salts, thereby affecting the acidity of cloud water and aerosols. At present, the ammonia emissions which is the main component of fine particulate (particulate matter equal to or less than 2.5m in aerodynamic diameter; PM2.5), has become a global hot issue. Livestock and poultry breeding is the main emission source of ammonia, and the total amount of ammonia released by China's pig industry is much higher than that of Europe and North America. An in-depth study about ammonia emission from livestock sources may help policy-makers to develop emission reduction scheme and ease the haze. Generally, pig is considered to be the major contributor to ammonia emission. Therefore, in this study, we investigated NH3emissions from a pig farm in Yangtze River delta region which were equipped with typical mechanical ventilation system and manure collection system cleaning by rising water. It monitored the ammonia emissions from different houses at the same time which included different growth stages of the fattening pigs and sows (among them, the fattening pigs can be divided in three phases according to the weight, Nursery (<24 kg), and Fattening-I (24-60 kg) and Fattening-Ⅱ(60-120 kg).The sow can be divided into Gestation and Farrowing, and the ammonia emission flux was determined. Meanwhile, in this study, we analyzed the ammonia emission characteristics to explore the contribution of ammonia emissions in different growth stage. The results showed that the NH3concentrations of Nursery, Fattening-Ⅰ, Fattening-Ⅱ, Gestation and Farrowing were (0.97±0.4), (3.37±0.70) and (5.45±2.30), (2.19±1.06) and (1.44±0.48) mg/m3, respectively. The ammonia emission in each column had a significant daily change process. In the morning, the ammonia discharge were fluctuated and increased, then started to decrease in the afternoon, and the value kept low at night. The ammonia emission rate was significantly positively correlated with the temperature and was negatively correlated with the humidity. The daily NH3emissions rate of Nursery, Fattening-Ⅰ, Fattening-Ⅱ, Gestation and Farrowing were 0.85, 6.53, 8.20, 10.39 and 13.86 g/(pig·d). In fattening pigs, the contribution rate of Nursery, Fattening-Ⅰ, Fattening-Ⅱwere 3.64%, 26.11% and 70.25%. In sows, the contribution rate of Gestation and Farrowing was 75.32% and 24.68%. Artificial disturbance, such as feeding and defecation, increased the ammonia emission in the pig houses. The ammonia emission rate of sows was 1.87 times higher than fattening pigs. By monitoring the concentration of ammonia emission from fattened pigs and sows at different growth stages, we explored the characteristics of ammonia emission from large-scale pig farms, discriminated and analyzed the important influencing factors of ammonia emission, and discussed the contribution of fattened pigs and sows of different types to ammonia emission during growth stages to provide technical support for the accounting of ammonia emission in regional livestock and poultry breeding. These findings in this paper could be useful for estimation of ammonia emissions accurately and implementation of ammonia emission reduction measures in China.
ammonia; emission control; pollution; industrial pig farm; manure cleaning by rising water
2018-03-19
2018-07-03
大氣重污染成因與治理攻關(guān)項目(DQGG0208);環(huán)保公益性行業(yè)科研專項(201509038);環(huán)境保護部部門預算項目“畜禽養(yǎng)殖大氣氨排放污染控制工作指南”;江蘇省大學生創(chuàng)新訓練計劃項目(201710304035Z、201710304078Y)聯(lián)合資助
王文林,副研究員,博士,主要研究方向為流域面源污染控制。Email:wangwenlin_jjl@126.cn
劉 波,副教授,博士,主要從事環(huán)境面源污染過程與防治研究。Email:lb@ntu.edu.cn
10.11975/j.issn.1002-6819.2018.17.028
X552
A
1002-6819(2018)-17-0214-08
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