都市污水中醣類、蛋白質與脂質定量定性分析研究

Abstract

厭氧生物處理在低水力停留時間操作條件下，會降低處理效率與甲烷產氣量，且三成分中的脂質與蛋白質存在轉換率與甲烷產率不佳等問題；因此厭氧降解上勢必對三成分進行深入研究，並建立定量定性分析方法。 研究探討內容包括總量檢測分析與細部組成分析。總量檢測分析上，醣類使用「蔥酮法」與「還原糖法」；蛋白質使用「莫瑞法」與「凱氏定氮法」；脂質使用「紅外線分析法」與「重量萃取法」，探討試驗比較後適合應用污水的分析方法。細部組成分析方面，使用氣相層析儀(GC)分析單糖組成並建立應用污水之分析方法。 醣類總量檢測上，蔥酮法定量極限(LOQ)與偵測極限(LOD)分別為3.75 mg/L與1.25 mg/L，還原糖法分別為3.60 mg/L與1.21 mg/L；若使用葡萄糖檢量線定量，兩方法總量檢測試驗8種單糖皆呈現不準確性，但兩方法主要差別在於蔥酮法對多糖檢測後之測值準確度高，且對污水添加回收率明顯優於還原糖法；單糖組成分析方面，GC-BID定量定性結果顯示8種單糖定量極限(LOQ)至少500 µg/L以下，偵測極限(LOD)至少200 µg/L以下，並能準確定量定性污水中單糖組成。蛋白質總量檢測方面，莫瑞法定量極限(LOQ)與偵測極限(LOD)分別為2.78 mg/L與0.93 mg/L，凱氏定氮法則是在試驗過程中無法符合品管要求，顯示凱氏定氮法之分析極限範圍明顯高於10 mg/L。脂質總量檢測方面，紅外線分析之定量極限(LOQ)與偵測極限(LOD)分別為2.18 mg/L與0.73 mg/L；然而重量萃取法查核試驗呈現低回收率，導致污水測值嚴重低估。 整體而言，總量檢測試驗討論，醣類、蛋白質與脂質適合的分析方法為「蔥酮法」、「莫瑞法」與「紅外線分析法」；適合之總量檢測方法若應用在都市污水三成分分析上，檢測水樣無論在初沉前與初沉後，脂質占污水中有機物比重最高，蛋白質次之，醣類最低。根據此結果，推論厭氧處理應用在都市污水的研究上，會因為脂質濃度過高以及低水力停留時間等操作條件，而影響最終有機物降解與產甲烷效能。

With regards to domestic wastewater, anaerobic biological treatment processes in lower hydraulic retention time (HRT) could reduce the production of methane gas and the removal rate. Furthermore, the lipids and proteins have a poor conversion rate and methane yield, so the decomposition of carbohydrates, proteins and lipids in anaerobic treatment can be discussed in-depth, and quantitative and qualitative methods can be researched. The research discusses the analysis including the total quantification and quantitation. In the analysis of total quantification, the methods that are appropriate for the application in domestic wastewater are discussed. The Anthrone method and reducing sugar method can be used on carbohydrates; the Lowry method and Kjeldahl method can be used on proteins; and the infrared spectrometric method and gravimetric extraction method can be used on lipids. During the qualitative analysis, a gas chromatograph (GC) was used to analyze the composition of monosaccharides and establish an analytical method for the application in domestic wastewater. The results of the carbohydrates analysis, LOD and LOQ in Anthrone method and reducing sugar method were 1.25 and 3.74, 1.21 and 3.63 mg/L, respectively. However, the results showed that the reactivity of all types of carbohydrates in terms of the calibration curve of glucose represented the different degree of absorbance resulting in underestimating their values, and the differences between both methods are that reducing sugar method has a lower recovery rate of polysaccharide than the Anthrone method, and the recovery rate of reducing sugar method was lower than Anthrone method. As for the GC method, it showed a great precision for the quantification of the individual monosaccharides, an assay of each monosaccharide was observed on LOD and LOQ at least 200 and 500 µg/L, respectively. The results of the proteins analysis, LOD and LOQ in the Lowry method were 0.93 and 2.78 mg/L, respectively. The Kjeldahl method didn’t meet the quality criterion during the study at 10 mg/L assay, so the range limit was significantly higher than 10 mg/L. The results of lipids analysis, LOD and LOQ using the Infrared spectrometric method were 0.73 and 2.18 mg/L, respectively. However, the recovery rate of the Gravimetric extraction method showed was much lower, demonstrating a significant underestimation. In conclusion, as for the comparison of the Quantification methods, the Anthrone method, Lowry method and Infrared Spectrometric method are appropriate for carbohydrates, proteins and lipids analysis in domestic wastewater. A case study was performed using the appropriate methods for domestic wastewater from different areas, showing the highest proportion of organic matters (OMs) was lipids, followed by proteins. According to these results, it could be inferred that using anaerobic treatment in domestic wastewater could affect the degradation of organic matter and methane production due to high lipids and proteins following the lower hydraulic retention time (HRT).