張 曦,孟海波,劉文杰,3,沈玉君,趙立欣,張朋月,王 健,周海賓,程紅勝,宋立秋
蔬菜廢棄物與畜禽糞便聯(lián)合好氧發(fā)酵揮發(fā)性有機(jī)物排放特征
張 曦1,2,孟海波1,2,劉文杰1,2,3,沈玉君1,2※,趙立欣1,張朋月1,2,王 健1,2,周海賓1,2,程紅勝1,2,宋立秋1,2
(1. 農(nóng)業(yè)農(nóng)村部規(guī)劃設(shè)計研究院,北京 100125;2. 農(nóng)業(yè)農(nóng)村部資源循環(huán)利用技術(shù)與模式重點實驗室,北京 100125;3. 黑龍江八一農(nóng)墾大學(xué),大慶 163319)
為研究蔬菜廢棄物與畜禽糞便聯(lián)合好氧發(fā)酵過程產(chǎn)生的揮發(fā)性有機(jī)物(volatile organic compound,VOCs)及主要致臭物質(zhì),開展了蔬菜廢棄物與畜禽糞便聯(lián)合好氧發(fā)酵試驗,采用氣相色譜-質(zhì)譜法和三點比較式臭袋法分析了好氧發(fā)酵升溫、高溫和降溫階段產(chǎn)生的VOCs種類和濃度及臭氣濃度。結(jié)果表明,蔬菜廢棄物與畜禽糞便聯(lián)合好氧發(fā)酵過程共檢出34種VOCs,其中芳香烴類化合物11種、烷烴7種、含硫化合物4種、酮類4種、鹵烴類化合物3種、醇類2種、酯類2種、醛類1種;發(fā)酵升溫期臭氣濃度最大,達(dá)72 443,而在降溫期產(chǎn)生的VOCs種類最多為29;在聯(lián)合好氧發(fā)酵過程中主要致臭物質(zhì)為甲硫醚、二甲二硫醚、二硫化碳、NH3和H2S,羰基硫、乙醛和苯乙烯僅在高溫期產(chǎn)生且濃度較高;根據(jù)嗅閾值比值大小與最大濃度,需重點監(jiān)測和控制惡臭物質(zhì)的順序是二甲二硫醚>H2S>NH3>甲硫醚。該研究結(jié)果為蔬菜廢棄物與畜禽糞便聯(lián)合好氧發(fā)酵過程中惡臭物質(zhì)的監(jiān)測和控制策略研究提供理論依據(jù)。
廢棄物;糞便;排放控制;聯(lián)合好氧發(fā)酵;揮發(fā)性有機(jī)物;致臭物質(zhì)
中國蔬菜種植面積和產(chǎn)量都居于世界前列,據(jù)統(tǒng)計,2017年中國蔬菜種植面積超過199.8萬hm2,產(chǎn)量超過6.9億t[1],隨之產(chǎn)生的蔬菜廢棄物的總量高達(dá)約2.69億t[2],成為僅次于水稻、玉米和小麥秸稈的第四大農(nóng)作物廢棄物[3]。蔬菜廢棄物含水率一般為75%~95%,養(yǎng)分含量也較高,如氮(N,1.3%~5.7%)、磷(P,0.3%~3.3%)和鉀(K,0.5%~5.4%)(以干物質(zhì)計),但其易腐爛、保存周期短、不易運輸?shù)萚4-6]。好氧發(fā)酵是有機(jī)廢棄物無害化、資源化利用的有效途徑,已廣泛應(yīng)用于各類蔬菜廢棄物的處理研究[7-8]。但蔬菜廢棄物含水率較高,且C/N比較低,大多在10以下[9],難以單獨進(jìn)行好氧發(fā)酵。在實際生產(chǎn)中,一般與畜禽糞便、秸稈等有機(jī)廢棄物聯(lián)合進(jìn)行好氧發(fā)酵,以保證水分、C/N比等參數(shù)在適宜范圍。
在好氧發(fā)酵過程中會產(chǎn)生和排放大量的揮發(fā)性有機(jī)物(volatile organic compounds,VOCs),排放質(zhì)量濃度最高可達(dá)14 547 mg/m3[10],種類達(dá)100多種以上[11],且不同有機(jī)廢棄物產(chǎn)生的VOCs濃度和種類不盡相同。張紅玉等[12]在廚余垃圾好氧發(fā)酵過程中檢出二甲二硫、甲硫醇、硫化氫(H2S)、1,3-二甲基苯、鄰二甲苯和對二甲苯等43種VOCs;Defoer等[13]在蔬菜水果和庭院垃圾聯(lián)合好氧發(fā)酵過程中檢出VOCs共89種,其中總VOCs質(zhì)量濃度為0.09~23.6 mg/m3;沈玉君等[14]在豬糞好氧發(fā)酵過程中檢出31種VOCs,甲硫醚、二甲二硫、二甲三硫、乙醛和H2S等為主要致臭物質(zhì);朱彥莉[15]研究發(fā)現(xiàn)城市污泥好氧發(fā)酵過程共排放75種VOCs,主要致臭物質(zhì)是甲硫醇、二甲基二硫醚、二甲基硫醚、H2S、NH3、二硫化碳。此外,在好氧發(fā)酵不同階段產(chǎn)生和釋放的VOCs差異也較大,相關(guān)研究發(fā)現(xiàn)VOCs排放主要集中在好氧發(fā)酵前期[16-18]。Kumar等[18]研究表明園林廢棄物好氧發(fā)酵前期的VOCs排放速率(最大為12.95 mg/m3)約為后期的5倍;周談龍等[19]以豬糞為原料開展中試規(guī)模好氧發(fā)酵研究發(fā)現(xiàn)VOCs的產(chǎn)生和排放主要集中在前2周;Turan等[10]研究發(fā)現(xiàn)雞糞好氧發(fā)酵過程VOCs的產(chǎn)生也主要在前期;Shen等[20]以城市污泥為好氧發(fā)酵原料研究發(fā)現(xiàn)VOCs排放主要發(fā)生在好氧發(fā)酵升溫期。目前針對好氧發(fā)酵過程VOCs排放特征與惡臭物質(zhì)分析的研究主要集中在畜禽糞便、城市污泥、生活垃圾、廚余垃圾等單一原料好氧發(fā)酵,而針對蔬菜廢棄物與畜禽糞便多原料聯(lián)合好氧發(fā)酵過程產(chǎn)生的VOCs種類及排放特征研究較少。
本研究以蔬菜廢棄物和畜禽糞便為原料開展聯(lián)合好氧發(fā)酵試驗,定量分析好氧發(fā)酵升溫、高溫、降溫3個不同發(fā)酵階段產(chǎn)生的VOCs和臭氣濃度,明確VOCs的排放清單及主要致臭物質(zhì),為農(nóng)業(yè)農(nóng)村有機(jī)廢棄物好氧發(fā)酵過程臭氣控制提供理論依據(jù)。
試驗原料主要是蔬菜廢棄物和畜禽糞便,輔料為玉米秸稈。蔬菜廢棄物為葉菜類蔬菜廢棄物,取自周邊菜市場,主要為丟棄的生菜、快菜、苦菊、油麥菜等葉菜類蔬菜;畜禽糞便為豬糞,取自北京市順義區(qū)東華山村;玉米秸稈采購自山東省,晾干并粉碎至1 cm左右。表1為供試材料的基本性質(zhì)。
表1 試驗材料基本性質(zhì)
本試驗采用強(qiáng)制通風(fēng)好氧發(fā)酵工藝,實驗裝置為密閉式好氧發(fā)酵反應(yīng)器(如圖1所示)。為調(diào)節(jié)發(fā)酵物料含水率、C/N等,采用蔬菜廢棄物與豬糞為主要原料聯(lián)合發(fā)酵,并以玉米秸稈作為輔料,根據(jù)預(yù)試驗結(jié)果,按照鮮質(zhì)量比10∶4∶3混合均勻,調(diào)節(jié)發(fā)酵物料C/N比約為25∶1,含水率為65%~70%,裝入60 L的反應(yīng)器中進(jìn)行好氧發(fā)酵。發(fā)酵過程中采用間歇式強(qiáng)制通風(fēng),在升溫期(<45℃)每隔30 min鼓風(fēng)曝氣5 min,高溫期(>45 ℃)每隔20 min鼓風(fēng)曝氣5 min,降溫期(<45℃)每隔40 min鼓風(fēng)曝氣5 min,通風(fēng)量為0.25 m3/(min?m3),此外,為提高好氧發(fā)酵效率,促進(jìn)物料腐熟,分別在第8天、第12天和第19天翻堆。發(fā)酵周期為20 d,在第1天(升溫期)、第4天(高溫期)、第10天(降溫期)采集氣體樣品。氣體采集均在鼓風(fēng)曝氣前,采樣方法為采樣袋(5 L)外負(fù)壓法,然后送國家環(huán)境保護(hù)惡臭污染控制重點實驗室測定VOCs各組分及臭氣濃度。
VOCs各組分與濃度分析,采用US EPA-14、15方法,將800 mL采集的樣品氣體經(jīng)過ENTECH 7100冷阱預(yù)濃縮系統(tǒng)濃縮,脫除水蒸氣、CO2、N2和O2后,進(jìn)入氣相色譜-質(zhì)譜儀系統(tǒng)(美國Angilent 7890-5975C)進(jìn)行分析測定。采用不分流進(jìn)樣,氣相色譜條件如下:色譜柱為DB-5MS 60 m×0.32 mm×1.0m,載氣氦氣> 99.999%,載氣流速為1.5 mL/min,采用程序升溫,先在35 ℃下保持5 min,然后以5 ℃/min升溫至150 ℃,再以15 ℃/min升溫至220 ℃保持7 min,進(jìn)樣口溫度為100 ℃;質(zhì)譜分析條件如下:離子源溫度為230 ℃,四極桿溫度為150 ℃,接口溫度為280 ℃,質(zhì)量范圍為15~300 amu,掃描速度0.2 s/scan,EI源條件為70 eV,質(zhì)譜掃描為全掃描和選擇離子檢測方式。每次樣品分析之前,使用含有102種NMOCs(烷烴28種,烯烴10種,芳香烴17種,鹵代烷烯烴類37種,以及醇、醛、酮、酯、醚類氧烷烴共10種)的混合標(biāo)準(zhǔn)氣體(美國Spectra Gases公司)對標(biāo)準(zhǔn)曲線進(jìn)行校準(zhǔn)。樣品定性通過各有機(jī)物的保留時間和譜庫中標(biāo)準(zhǔn)質(zhì)譜圖檢索來進(jìn)行,定量則使用內(nèi)標(biāo)法;所使用標(biāo)準(zhǔn)氣體的基底氣體為氮氣[21]。
① 通風(fēng)、溫度控制系統(tǒng)②溫度采集器③氣體采樣孔④固體采樣孔⑤氣泵
臭氣濃度的測定采用三點比較式臭袋法(GB/T 14675-1993);氨氣(NH3)采用硼酸溶液吸收,鹽酸滴定法測定;H2S測定采用亞甲基藍(lán)分光光度法。各目標(biāo)氣體每個監(jiān)測日均采集3個平行樣品,濃度平均值作為當(dāng)日氣體排放濃度。各種氣體采樣時間互不干擾,分段進(jìn)行。
好氧發(fā)酵過程中,采用PT100探頭連續(xù)監(jiān)測記錄溫度的變化;氧氣濃度為復(fù)合氣體測試儀測定的發(fā)酵罐內(nèi)上端排氣口氧氣濃度,并在鼓風(fēng)前期完成測定,以確保排氣口濃度與發(fā)酵物料內(nèi)部濃度差異較小。
圖2為蔬菜廢棄物與畜禽糞便聯(lián)合好氧發(fā)酵過程中溫度的變化,呈先上升后下降的趨勢,發(fā)酵第3天溫度上升到55 ℃,第6天溫度達(dá)到最高72 ℃,從第10天開始溫度降至50 ℃以下,整個發(fā)酵過程55 ℃以上高溫期持續(xù)6 d,50 ℃以上高溫期持續(xù)7 d,達(dá)到畜禽糞便堆肥技術(shù)規(guī)范(NY/T 3442—2019)反應(yīng)器堆肥55 ℃以上至少持續(xù)5 d[22]和畜禽糞便無害化處理技術(shù)規(guī)范(GB/T 36195—2018)中密閉式堆肥保持50 ℃以上至少7 d[23]的要求。溫度是好氧發(fā)酵無害化程度的重要指標(biāo),高溫(55~65 ℃)是殺滅病原微生物的必要條件[24],但也有研究表明,蔬菜類廢棄物好氧發(fā)酵高溫期需達(dá)到70 ℃以上,才能殺滅病毒性病原菌,但溫度過高微生物活性降低,影響有機(jī)物質(zhì)降解[25]。
氧氣濃度的變化與溫度變化的過程相反,呈先下降后上升的趨勢,在發(fā)酵前期氧氣濃度顯著降低,隨后又緩慢上升,這主要是由于好氧發(fā)酵前期微生物活性逐漸增強(qiáng)且大量繁殖,氧氣的消耗逐漸增多,氧氣濃度快速下降[26];此外,在好氧發(fā)酵前期,蔬菜廢棄物中水分未完全析出,發(fā)酵物料的含水率相對較高,不利于氧氣的傳輸;隨著發(fā)酵進(jìn)行,蔬菜廢棄物水分逐漸析出,發(fā)酵物料內(nèi)部氧氣傳輸暢通,好氧微生物活性逐漸增大,有機(jī)物分解速度也增大,并釋放出大量的熱能,從而使發(fā)酵物料溫度快速升高;在發(fā)酵后期,有機(jī)物分解基本趨于穩(wěn)定,微生物活性逐漸降低,氧氣消耗量逐漸減少,發(fā)酵物料溫度也隨之下降[19,25]。統(tǒng)計分析表明,蔬菜廢棄物與畜禽糞便聯(lián)合好氧發(fā)酵過程中溫度和氧氣濃度變化呈極顯著負(fù)相關(guān)(<0.01)。
圖2 好氧發(fā)酵過程中溫度與氧氣濃度變化
在蔬菜廢棄物與畜禽糞便聯(lián)合好氧發(fā)酵過程中共檢測出34種揮發(fā)性物質(zhì)(見表2),其中含硫化合物4種,分別為甲硫醚、二甲二硫醚、羰基硫、二硫化碳;酯類2種,分別為乙酸丁酯、乙酸乙酯;醇類2種,分別為乙醇、異丙醇;醛類1種,為乙醛;酮類4種,分別為丙酮、2-丁酮、2-己酮、甲基異丁酮;鹵烴類化合物3種,分別為二氯甲烷、氯仿(三氯甲烷)、1,2-二氯乙烷;烷烴7種,分別為2-甲基丁烷、戊烷、甲基環(huán)戊烷、2-甲基戊烷、3-甲基戊烷、正己烷、辛烷;芳香烴類化合物11種,分別為苯、甲苯、1,2,3-三甲苯、間二甲苯、對二甲苯、鄰二甲苯、乙苯、2-甲基 -1,3-丁二烯、a-蒎烯、檸檬烯、苯乙烯,另外還有揮發(fā)性無機(jī)物NH3和H2S。其中包括187種美國重點控制有毒空氣污染物中的12種[27],22種日本環(huán)保署規(guī)定控制的惡臭污染物中的5種[28],8種中國環(huán)保部規(guī)定控制的惡臭污染物中的3種[29]。
本研究蔬菜廢棄物與畜禽糞便聯(lián)合好氧發(fā)酵過程檢測到的VOCs排放數(shù)量比已有研究中以廚余垃圾、畜禽糞便、生活垃圾、食品垃圾及城市污泥為原料的好氧發(fā)酵過程VOCs的排放種類少[13,15,20-21,30-31],這可能由于發(fā)酵原料特性差異較大,且原料中含有較為豐富且易降解的蛋白質(zhì)和脂肪等有機(jī)物[12,14]。在種類上,發(fā)酵原料不同,VOCs排放種類也存在較大差異,沈玉君等[14]研究表明豬糞好氧發(fā)酵過程檢測到的31種VOCs主要包括芳香烴12種,醛類8種,鹵代烴4種,硫醇硫醚類4種,酮類2種,胺類1種;張紅玉等[32]研究發(fā)現(xiàn)生活垃圾好氧發(fā)酵過程排放的50種VOCs主要包括烴類化合物25種、芳香烴類化合物14種、含硫惡臭物質(zhì)5種及其他物質(zhì)6種。
表2 蔬菜廢棄物與畜禽糞便聯(lián)合好氧發(fā)酵過程中排放的揮發(fā)性物質(zhì)變化
注:“-”表示該物質(zhì)濃度低于檢出限;“/”表示未查詢到的嗅閾值。?美國重點控制有毒空氣污染物;?日本惡臭控制污染物;?中國惡臭控制污染物。
Note: “-” indicates that the substance concentration is lower than the detection limit; “/” indicates no query to the olfactory threshold. ? indicates hazardous air pollutants in US EPA; ? indicates odor control pollutants in Japan; ?indicates odor control pollutants in China.
圖3為蔬菜廢棄物與畜禽糞便聯(lián)合好氧發(fā)酵過程升溫期、高溫期和降溫期VOCs排放GC-MS圖譜。可以看出,在升溫期檢測到18種VOCs,而高溫期檢測到的VOCs種類最少,共16種,降溫期檢測到VOCs共29種,且隨著好氧發(fā)酵時間的增加,臭氣濃度逐漸減小。這可能是由于發(fā)酵前期微生物活動較為劇烈,易降解有機(jī)物質(zhì)快速降解,氧氣大量消耗,加上蔬菜廢棄物水分含量較高,發(fā)酵物料內(nèi)部氧氣濃度較低,導(dǎo)致微生物在此環(huán)境下分解產(chǎn)生較多VOCs,而在降溫階段易降解有機(jī)質(zhì)逐漸減少、溫度回落,發(fā)酵物料趨于腐熟,產(chǎn)生的臭氣隨之降低,但相比發(fā)酵前期產(chǎn)生了大量烷烴,VOCs種類有所增加[14,33]。在聯(lián)合好氧發(fā)酵不同階段產(chǎn)生的VOCs不盡相同,根據(jù)峰值面積及出現(xiàn)次數(shù),二甲二硫醚和丙酮在各個時期均有出現(xiàn),甲硫醚在高溫期和降溫期出現(xiàn),但其峰值面積較大,也需要重點關(guān)注。
①乙醛 ②丙酮 ③2-丁酮 ④二甲二硫醚①Carbonyl sulfide ②Acetaldehyde ③2-Butanone ④Disulfide dimethyla. 升溫期 a. Mesophilic phase①丙酮 ②2-甲基-1,3-丁二烯 ③甲硫醚 ④二甲二硫醚①Acetone ②2-methyl-1,3-butadiene ③Dimethyl sulfide ④Disulfide, dimethylb. 高溫期 b. Thermophilic phase①乙醇 ②丙酮 ③甲硫醚 ④正己烷 ⑤二甲二硫醚 ⑥甲苯 ⑦乙苯①Ethanol ②Acetone ③Dimethyl sulfide ④n-Hexane ⑤Disulfide dimethyl ⑥Toluene ⑦Ethylbenzenec. 降溫期 c. Cooling phase
臭氣濃度是表征惡臭污染對人體嗅覺刺激程度的指標(biāo),也是表征惡臭物質(zhì)的綜合指標(biāo)。從表2中可以看出,在蔬菜廢棄物與畜禽糞便聯(lián)合好氧發(fā)酵升溫期臭氣濃度最高,達(dá)到72 443,之后逐漸降低,降溫期降至229。在34種VOCs中,甲硫醚、二甲二硫醚、二硫化碳、羰基硫、乙醛、甲基異丁酮、苯乙烯,及揮發(fā)性無機(jī)物H2S和NH3都超出了各自的嗅閾值,其他物質(zhì)均低于各自嗅閾值。因此,這9類物質(zhì)是蔬菜廢棄物與畜禽糞便聯(lián)合過程惡臭氣體的主要組分。
在超出各自嗅閾值的這9種揮發(fā)性物質(zhì)中,羰基硫、乙醛、甲基異丁酮、苯乙烯只出現(xiàn)在升溫期,羰基硫濃度達(dá)到其嗅閾值濃度的12.5倍,乙醛濃度達(dá)到其嗅閾值濃度的891.7倍,苯乙烯濃度為其嗅閾值濃度的8.7倍,且已被列入中國惡臭污染物排放標(biāo)準(zhǔn)(GB 14554—2018)[29],甲基異丁酮濃度也超出自身嗅閾值但濃度較低。根據(jù)臭氣濃度與嗅閾值的關(guān)系,在升溫階段產(chǎn)生的惡臭物質(zhì)危害排序為乙醛>羰基硫>苯乙烯>甲基異丁酮。甲硫醚在高溫期和降溫期均產(chǎn)生,且最大濃度達(dá)到其嗅閾值濃度的58倍,在好氧發(fā)酵過程中含硫化合物一直作為惡臭污染的重點關(guān)注對象[34-35]。此外,二硫化碳、二甲二硫醚、2-甲基-1,3-丁二烯,在升溫、高溫、降溫期均有產(chǎn)生,且二甲二硫醚、二硫化碳濃度與臭氣濃度的變化趨勢一致,相比于二硫化碳,二甲二硫醚濃度較高,且其最大濃度達(dá)到其嗅閾值濃度的45.2倍,2-甲基-1,3-丁二烯的嗅閾值未知。
除34種VOCs外,還檢出揮發(fā)性無機(jī)物NH3和H2S,從表2可以看出,發(fā)酵過程中H2S從0.446 mg/m3下降至0.036 mg/m3,呈現(xiàn)逐漸降低的趨勢,而NH3濃度從27.57 mg/m3升高至85 mg/m3,然后逐漸降低至21.25 mg/m3,呈現(xiàn)先升高后降低的趨勢。好氧發(fā)酵升溫、高溫和降溫各個階段的NH3和H2S排放濃度均高于其嗅閾值,H2S最大濃度為其檢知嗅閾值的372倍,NH3最大濃度為其檢知嗅閾值的283倍。
好氧發(fā)酵原料不同,排放的主要致臭物質(zhì)也存在一定差異。沈玉君等[14]研究表明豬糞好氧發(fā)酵過程的主要致臭物質(zhì)為甲硫醚、二甲二硫、二甲三硫、乙醛和H2S。周談龍等[19]等研究發(fā)現(xiàn)豬糞在中試規(guī)模好氧發(fā)酵過程中釋放的主要致臭物質(zhì)為三甲胺、二甲基硫、二甲基二硫和二甲基三硫。可以看出,與豬糞好氧發(fā)酵相比,本研究蔬菜廢棄物與畜禽糞便聯(lián)合好氧發(fā)酵過程中產(chǎn)生的主要致臭物質(zhì)也存在較大差異。
為進(jìn)一步明確蔬菜廢棄物與畜禽糞便聯(lián)合好氧發(fā)酵過程中主要臭氣物質(zhì)對臭氣濃度的貢獻(xiàn)大小,對升溫、高溫和降溫不同發(fā)酵階段排放的主要惡臭物質(zhì)濃度和臭氣濃度的進(jìn)行相關(guān)性分析(表3)??梢钥闯?,二甲二硫醚、H2S與臭氣濃度呈極顯著正相關(guān)(<0.01),二硫化碳與臭氣濃度呈顯著性相關(guān)(<0.05),甲硫醚和NH3與臭氣濃度相關(guān)性不大,但甲硫醚和NH3濃度較高,且有強(qiáng)烈的刺激性氣味,對臭氣濃度貢獻(xiàn)較大,應(yīng)進(jìn)行重點監(jiān)測與控制。此外,二甲二硫醚、H2S、二硫化碳三者之間均顯著相關(guān)(<0.05)。二甲二硫醚、H2S、二硫化碳、NH3和甲硫醚應(yīng)作為蔬菜廢棄物聯(lián)合好氧發(fā)酵整個過程中的主要致臭物質(zhì),根據(jù)最大濃度與嗅閾值比值大小,重點監(jiān)測和控制惡臭物質(zhì)的順序是二甲二硫醚>H2S>NH3>甲硫醚,二甲二硫醚應(yīng)是整個好氧發(fā)酵過程的首要關(guān)注對象。
表3 臭氣濃度及各臭氣組分的相關(guān)性分析
注:**表示α在0.01 水平上顯著相關(guān),*表示α在0.05 水平上顯著相關(guān)。
Note: ** indicate significant at 0.01 level, * indicate significant at 0.05 level.
影響好氧發(fā)酵VOCs產(chǎn)生和排放濃度的內(nèi)源因素包括pH值、含水率、C/N比、溫度等工藝參數(shù)[36-37],調(diào)控蔬菜廢棄物與畜禽糞便聯(lián)合好氧發(fā)酵工藝參數(shù)對于惡臭物質(zhì)的排放與控制具有重要作用。Delgado-Rodríguez等[36,38-39]研究了C/N比、含水率、通風(fēng)對固體廢棄物好氧發(fā)酵過程中VOCs產(chǎn)生排放的影響,發(fā)現(xiàn)C/N比>50、含水率為55%、通風(fēng)率為0.05 L/(kg?min)時VOCs的產(chǎn)生量較低;沈玉君等[40]研究了豬糞好氧發(fā)酵過程中C/N比、通風(fēng)速和含水率率等工藝參數(shù)對主要VOCs產(chǎn)生和排放的影響,提出含水率65%,C/N比30,通風(fēng)速率0.1 m3/(min?m3)能有效控制VOCs排放。本研究僅監(jiān)測了蔬菜廢棄物與豬糞、玉米秸稈好氧發(fā)酵過程排放的VOCs,為進(jìn)一步了解蔬菜廢棄物好氧發(fā)酵過程的VOCs排放,還需對蔬菜廢棄物與不同原料混合、不同發(fā)酵條件下VOCs氣體排放進(jìn)行監(jiān)測。
1)蔬菜廢棄物與畜禽糞便聯(lián)合好氧發(fā)酵過程中檢出VOCs共34種,其中芳香烴類化合物11種、烷烴7種、含硫化合物4種、酮類4種、鹵烴類化合物3種、酯類2種、醇類2種和醛類1種。好氧發(fā)酵升溫期臭氣濃度最大,達(dá)72 443,而在降溫期產(chǎn)生的VOCs種類最多為29。
2)在蔬菜廢棄物與畜禽糞便聯(lián)合好氧發(fā)酵過程中主要致臭物質(zhì)為二甲二硫醚、甲硫醚、二硫化碳、NH3和H2S,在升溫期還應(yīng)關(guān)注羰基硫、乙醛和苯乙烯;根據(jù)最大濃度與嗅閾值比值大小,重點監(jiān)測和控制惡臭物質(zhì)的順序是二甲二硫醚>H2S>NH3>甲硫醚,二甲二硫醚應(yīng)是蔬菜廢棄物與畜禽糞便聯(lián)合好氧發(fā)酵過程的首要關(guān)注對象。
[1] 國家統(tǒng)計局農(nóng)村社會經(jīng)濟(jì)調(diào)查司. 中國農(nóng)村統(tǒng)計年鑒2018[M]. 北京:中國統(tǒng)計出版社,2018.
[2] 王亞利,楊光,熊才耘,等. 蔬菜廢棄物蚯蚓堆肥對雞毛菜生長的影響[J]. 農(nóng)業(yè)環(huán)境科學(xué)學(xué)報,2017,36(10):2129-2135. Wang Yali, Yang Guang, Xiong Caiyun, et al. Effect of vegetable waste vermicompost on the growth of Brassica chinensis[J]. Journal of Agricultural Resources and Environment, 2017, 36(10): 2129-2135. (in Chinese with English abstract)
[3] 畢于運,王亞靜,高春雨. 中國主要秸稈資源數(shù)量及其區(qū)域分布[J]. 農(nóng)機(jī)化研究,2010(3):1-7. Bi Yuyun, Wang Yajing, Gao Chunyu. Straw resource quantity and its regional distribution in China[J]. Journal of Agricultural Mechanization Research, 2010(3): 1-7. (in Chinese with English abstract)
[4] 秦淵淵,郭文忠,李靜,等. 蔬菜廢棄物資源化利用進(jìn)展[J]. 中國蔬菜,2018,356(10):23-30. Qin Yuanyuan, Guo Wenzhong, Li Jing, et al. Research progress in resource utilization of vegetable waste[J]. China Vegetables, 2018, 356(10): 23-30. (in Chinese with English abstract)
[5] 楊巖,孫欽平,李妮,等. 不同過磷酸鈣添加量對蔬菜廢棄物堆肥的影響[J]. 農(nóng)業(yè)資源與環(huán)境學(xué)報,2017,34(1):66-72. Yang Yan, Sun Qinping, Li Ni, et al. Effects of Different addition amounts of superphosphate on vegetable waste compost[J]. Journal of Agricultural Resources and Environment, 2017, 34(1): 66-72. (in Chinese with English abstract)
[6] Lu Wenjing, Wang Hongtao, Nie Yunyi, et al. Effect of inoculating flower stalks and vegetable waste with lingo-cellulolytic microorganisms on the composting process[J]. Journal of Environmental Science & Health, 2004, 39(5/6): 871-887.
[7] 常瑞雪,王騫,甘晶晶,等. 易降解有機(jī)質(zhì)含量對黃瓜秧堆肥腐熟和氮損失的影響[J]. 農(nóng)業(yè)工程學(xué)報,2017,33(1):231-237. Chang Ruixue, Wang Qian, Gan Jingjing, et al. Influence of easily-degraded organic matter content on maturity and nitrogen loss during composting of cucumber vine[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2017, 33(1): 231-237. (in Chinese with English abstract)
[8] Maniadakis K, Lasaridi K, Manios Y, et al. Integrated waste management through producers and consumers education: Composting of vegetable crop residues for reuse in cultivation[J]. Journal of Environmental Science and Health Part B-pesticides, Food Contaminants, and Agricultural Wastes, 2004, B39(1): 169-183.
[9] 呂瀟,常瑞雪,毛瑞鑫,等. 添加炭基材料對蔬菜廢物好氧堆肥進(jìn)程和腐熟度的影響[J]. 環(huán)境工程學(xué)報,2015,9(3):1422-1426. Lü Xiao, Chang Ruixue, Mao Ruixin, et al. Effect of adding carbon-based materials on composting process and maturity of vegetable wastes[J]. Chinese Journal of Environmental Engineering, 2015, 9(3): 1422-1426. (in Chinese with English abstract)
[10] Turan Nurdan Gamze, Akdemir Andac, Ergun Osman Nuri. Emission of volatile organic compounds during composting of poultry litter[J]. Water Air and Soil Pollution, 2007, 184(1): 177-182.
[11] Scaglia Barbara, Orzi Valentina, Artola Adriana, et al. Odours and volatile organic compounds emitted from municipal solid waste at different stage of decomposition and relationship with biological stability[J]. Bioresource Technology, 2011, 102(7): 4638-4645.
[12] 張紅玉,鄒克華,楊金兵,等. 廚余垃圾堆肥過程中惡臭物質(zhì)分析[J]. 環(huán)境科學(xué),2012,33(8):2563-2568. Zhang Hongyu, Zou Kehua, Yang Jinbing, et al. Analysis of odor pollutants in kitchen waste composting[J]. Environmental Science, 2012, 33(8): 2563-2568. (in Chinese with English abstract)
[13] Defoer Nele, De Bo Inge, Van Langenhove Herman, et al. Gas chromatography-mass spectrometry as a tool for estimating odour concentrations of biofilter effluents at aerobic composting and rendering plants[J]. Journal of Chromatography A, 2002, 970(1): 259-273.
[14] 沈玉君,張朋月,趙立欣,等. 豬糞好氧發(fā)酵過程中揮發(fā)性有機(jī)物組分分析及致臭因子的確定[J]. 農(nóng)業(yè)工程學(xué)報,2016,32(4):205-210. Shen Yujun, Zhang Pengyue, Zhao Lixin, et al. Component analysis of volatile organic compounds and determination of key odor in pig manure aerobic fermentation process[J]. Transactions of the Chinese Society of Agricultural Engineering(Transactions of the CSAE), 2016, 32(4): 205-210. (in Chinese with English abstract)
[15] 朱彥莉. 污泥好氧發(fā)酵過程中臭氣釋放特征與影響因素[D]. 北京:中國科學(xué)院,2016.
[16] 沈玉君,高定,陳同斌,等. 堆肥過程中揮發(fā)性有機(jī)物的產(chǎn)生與釋放[J]. 中國給水排水,2011,27(11):101-108. Shen Yujun, Gao Ding, Chen Tongbin, et al. Production and emission of volatile organic compounds during composting[J]. China Water & Wastewater, 2011, 27(11): 101-108. (in Chinese with English abstract)
[17] 張朋月,沈玉君,劉樹慶. 畜禽糞便好氧發(fā)酵過程中揮發(fā)性氣體排放差異研究[J]. 農(nóng)業(yè)環(huán)境科學(xué)學(xué)報,2015,34(7):1378-1383. Zhang Pengyue, Shen Yujun, Liu Shuqing. Volatile gas emissions from different types of animal manure during aerobic fermentation process[J]. Journal of Agricultural Resources and Environment, 2015, 34(7): 1378-1383. (in Chinese with English abstract)
[18] Kumar Anuj, Alaimo Christopher P, Horowitz Robert, et al. Volatile organic compound emissions from green waste composting: Characterization and ozone formation[J]. Atmospheric Environment, 2011, 45(10): 1841-1848.
[19] 周談龍,尚斌,董紅敏,等. 中試規(guī)模豬糞堆肥揮發(fā)性有機(jī)物排放特征[J]. 農(nóng)業(yè)工程學(xué)報,2017,33(6):192-198. Zhou Tanlong, Shang Bin, Dong Hongmin, et al. Emission characteristics of volatile organic compounds during pilot swine manure composting[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2017, 33(6): 192-198. (in Chinese with English abstract)
[20] Shen Yujun, Chen Tongbin, Gao Ding, et al. Online monitoring of volatile organic compound production and emission during sewage sludge composting[J]. Bioresource Technology, 2012, 123(4): 463-470.
[21] 盧學(xué)強(qiáng),韓萌,冉靚,等. 天津中心城區(qū)夏季非甲烷有機(jī)化合物組成特征及其臭氧產(chǎn)生潛力分析[J]. 環(huán)境科學(xué)學(xué)報,2011,31(2):373-380. Lu Xueqiang, Han Meng, Ran Liang, et al. Characteristics of nonmethane organic compounds and their ozone formation potentials in down town Tianjin in Summer [J]. Acta Scientiae Circumstantiae, 2011, 31(2): 373-380. (in Chinese with English abstract)
[22] 畜禽糞便堆肥技術(shù)規(guī)范:NY/T 3442—2019[S]. 2019.
[23] 畜禽糞便無害化處理技術(shù)規(guī)范:GB/T 36195-2018[S]. 2018.
[24] Pandey Pramod K, Cao Wenlong, Biswas Sagor, et al. A new closed loop heating system for composting of green and food wastes[J]. Journal of Cleaner Production, 2016, 133: 1252-1259.
[25] 常瑞雪. 蔬菜廢棄物超高溫堆肥工藝構(gòu)建及其過程中的氮素?fù)p失研究[D]. 北京:中國農(nóng)業(yè)大學(xué),2017.
[26] Pagans Estela, Font Xavier, Sánchez Antoni. Emission of volatile organic compounds from composting of different solid wastes: Abatement by biofiltration[J]. Journal of Hazardous Materials, 2006, 131(1): 179-186.
[27] US. Environmental Protection Agency. Initial list of hazardous air pollutants with modifications [EB/OL]. [2019-02-21]. https://www.epa.gov/haps/initial-list-hazardous- air-pollutants-modifications
[28] 日本惡臭防治法[Z]. 1995.
[29] 惡臭污染物排放標(biāo)準(zhǔn):GB 14554-2018[S]. 2018.
[30] 吳婷,王新明. 食品垃圾好氧降解過程中揮發(fā)性有機(jī)物(VOCs)排放特征[J]. 環(huán)境科學(xué)學(xué)報,2012,32(10):2575-2583. Wu Ting, Wang Xinming. Release of volatile organic compounds from food wastes during the aerobic decomposition[J]. Acta Scientiae Circumstantiae, 2012, 32(10): 2575-2583. (in Chinese with English abstract)
[31] 邵珠澤,鄭國砥,王元剛,等. 生活垃圾堆肥設(shè)施VOCs排放特征及臭氧生成潛勢分析[J]. 環(huán)境科學(xué),2017,38(5):1783-1791. Shao Zhuze, Zheng Guodi, Wang Yuangang, et al. Emission characteristics and ozone formation potential of VOCs from a municipal solid waste composting plant[J]. Environmental Science, 2017, 38(5): 1783-1791. (in Chinese with English abstract)
[32] 張紅玉,李國學(xué),楊青原. 生活垃圾堆肥過程中惡臭物質(zhì)分析[J]. 農(nóng)業(yè)工程學(xué)報,2013,29(9):192-199. Zhang Hongyu, Li Guoxue, Yang Qingyuan. Odor pollutants analyzing during municipal solid waste (MSW) composting[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2013, 29(9): 192-199. (in Chinese with English abstract)
[33] 沈玉君,李國學(xué),任麗梅,等. 不同通風(fēng)速率對堆肥腐熟度和含氮氣體排放的影響[J]. 農(nóng)業(yè)環(huán)境科學(xué)學(xué)報,2010,29(9):1814-1819. Shen Yujun, Li Guoxue, Ren Limei, et al. The impact of composting with different aeration rates on maturity variation and emission of gas concluding N[J]. Journal of Agricultural Resources and Environment, 2010, 29(9): 1814-1819. (in Chinese with English abstract)
[34] Tsai Chung Jung, Chen Mei Lien, Ye An Di, et al. Fang. The relationship of odor concentration and the critical components emitted from food waste composting plants[J]. Atmospheric Environment, 2008, 42(35): 8246-8251.
[35] Hort C, Gravy S, Platel V, et al. Evaluation of sewage sludge and yard waste compost as a bio?lter media for theremoval of ammonia and volatile organic sulfur compounds (VOSCs)[J]. Chemical Engineering Journal, 2009, 152(1): 44-53.
[36] Delgado-Rodríguez M, Ruiz-Montoya M, Girldez I, et al. Effect of aeration rate and moisture content on the emissions of selected VOCs during municipal solid waste composting[J]. Journal of Material Cycles and Waste Management, 2012, 14(4): 371-378.
[37] Sundberg Cecilia, Yu Dan, Franke-whittle Ingrid, et al. Effects of pH and microbial composition on odour in food waste composting[J]. Waste Management, 2013, 33(1): 204-211
[38] Delgado- Rodríguez M, Ruiz-Montoya M, Giraldez I, et al. Effect of control parameters on emitted volatile compounds in municipal solid waste and pine trimmings composting[J]. Journal of Environmental Science and Health Part A, 2010, 45(7): 855-862.
[39] Delgado-Rodríguez M, Ruiz-Montoya M, Girldez I, et al. Influence of control parameters in VOCs evolution during MSW trimming residues composting[J]. Journal of Agricultural and Food Chemistry, 2011, 59(24): 13035-13042.
[40] 沈玉君,孟海波,張朋月,等. 豬糞堆肥揮發(fā)性有機(jī)物的產(chǎn)生規(guī)律與影響因素[J]. 農(nóng)業(yè)工程學(xué)報,2017,33(5):211-216. Shen Yujun, Meng Haibo, Zhang Pengyue, et al. Generation law and influencing factors of volatile organic compounds during pig manure composting[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2017, 33(5): 211-216. (in Chinese with English abstract)
Emission characteristics of volatile organic compounds during vegetable residues and livestock manure combined aerobic fermentation
Zhang Xi1,2, Meng Haibo1,2, Liu Wenjie1,2,3, Shen Yujun1,2※, Zhao Lixin1, Zhang Pengyue1,2, Wang Jian1,2, Zhou Haibin1,2, Cheng Hongsheng1,2, Song Liqiu1,2
(1.,100125,; 2.,,100125,; 3.,163319,)
The aerobic fermentation process will emit a trace of volatile organic compounds (VOCs), although the VOCs content is less, the effect on human health cannot be neglected. VOCs are not a single substance, but a class of compounds. However, the emission characteristics of VOCs and key odor substances during vegetable residues and livestock manures combined aerobic fermentation process is relatively limited at present. In order to investigate the characteristics of VOCs and key odor substances, vegetable residues and livestock manures combined aerobic fermentation was carried out, and the experiment lasted for 20 days in November 2018 at the Key Laboratory of Technology and Model for Cyclic Utilization from Agricultural Resources. The water content of leaf vegetable residues-pig manures-straw mixes for aerobic fermentation was 65%, and the ratio of carbon to nitrogen was 25:1. During the aerobic fermentation process, the forced ventilation was used, and the ventilation rate was 0.25 m3/(min·m3). The temperature inside the fermentation pile rose and exceeded 55 ℃ within 3 days, and kept above 50 ℃ for 7 days, kept above 55 ℃ for 6 days, which could secure pathogen inactivation and meet the non-hazardous requirement of national standards. The experiment to monitor volatile gas emission from the aerobic fermentation process, the VOCs concentration at different phases were analyzed and detected by GC-MS, and the odor concentration was determined by three-point comparative odor bag method. The results showed that 34 kinds of VOCs were detected, besides ammonia and hydrogen sulfide. The detected VOCs included carbonyl sulfide, methyl sulfide, carbon disulfide, dimethyl disulfide, butyl acetate, ethyl acetate, ethanol, isopropanol, acetaldehyde, acetone, 2-butanone, 2-hexanone, methyl isobutyl ketone, chloroform, dichloromethane, 1,2-dichloroethane, 2-methylbutane, pentane, 2-methylpentane, 3-methylpentane, methylcyclopentane, N-hexane, octane, a-pinene, limonene, 2-methyl-1,3-butadiene, toluene, ethylbenzene, m-xylene, p-xylene, styrene, o-xylene, 1,2, 3-trimethylbenzene, benzene. There were sulphurcompounds, esters compounds, aldehyde compounds, ketone compounds, alcohol compounds, halohydrocarbons, alkane compounds, aromatic compounds were 4, 2, 1, 4, 2, 3, 7 and 11, respectively. The highest odor concentration was 72 443 during the mesophilic phase, however the most variation of VOCs was up to 29 during the cooling phase. The correlation analysis between importance to smelly gases and odor concentration showed that the hydrogen sulfide and dimethyl disulfide were significantly positively correlated with odor concentration (<0.01). Carbon disulfide was significantly positively correlated with odor concentration (<0.05). The relationships between dimethyl sulfide, ammonia with ordor gas were not strong, but the concentration of dimethyl sulfide and ammonia were high and had a strong pungent odor. Beyond that, it contributed a lot to the odor concentration, and should be monitored and controlled. Therefore, the smelly and odor-causing matters of vergetable residues and livestock manures combined aerobic fermentation were mainly disulfide dimethyl, hydrogen sulfide, carbon disulfide, dimethyl sulfide and ammonia. In order to monitor the key odor substances and provide reference for making control strategy in the vergetable residues and livestock manure combined erobic fermentation, we recommended disulfide dimethyl, hydrogen sulfide as a foul odor pollution indicator. Next, we need to study the emission of VOCs from vergetable residues with different feedstocks and different fermentation conditions. The study provides data support for mitigating VOCs gas emissions during the composting of agricultural wastes aerobic fermentation.
wastes; manures; emission control; combined aerobic fermentation; olatile organic compounds; key odor substances
張 曦,孟海波,劉文杰,沈玉君,趙立欣,張朋月,王 健,周海賓,程紅勝,宋立秋. 蔬菜廢棄物與畜禽糞便聯(lián)合好氧發(fā)酵揮發(fā)性有機(jī)物排放特征[J]. 農(nóng)業(yè)工程學(xué)報,2019,35(22):193-199. doi:10.11975/j.issn.1002-6819.2019.22.023 http://www.tcsae.org
Zhang Xi, Meng Haibo, Liu Wenjie, Shen Yujun, Zhao Lixin, Zhang Pengyue, Wang Jian, Zhou Haibin, Cheng Hongsheng, Song Liqiu. Emission characteristics of volatile organic compounds during vegetable residues and livestock manure combined aerobic fermentation[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2019, 35(22): 193-199. (in Chinese with English abstract) doi:10.11975/j.issn.1002-6819.2019.22.023 http://www.tcsae.org
2019-04-28
2019-09-28
國家重點研發(fā)計劃:好氧發(fā)酵過程重金屬鈍化及高效生物除臭關(guān)鍵技術(shù)與設(shè)備研究(2016YFD0800603)
張曦,高級工程師,主要從事農(nóng)業(yè)廢棄物肥料化利用研究工作。Email:zhangxi@caaepd.org.cn
沈玉君,高級工程師,主要從事農(nóng)業(yè)廢棄物資源化利用研究工作。Email:shenyujun@caaepd.org.cn
10.11975/j.issn.1002-6819.2019.22.023
X71
A
1002-6819(2019)-22-0193-07