以活性污泥系統處理廢棄肉膠之可行性研究

Abstract

摘要 皮革工業的生皮原料經脫毛 (Un-hairing) 及浸灰 (Liming) 流程後，再透過削肉 (Fleshing) 將生皮及肉膠 (Leather fleshing) 分開，肉膠具極高的含水量及pH值 (12~13)，且肉膠廢棄物產量約佔製程中所使用生皮原料的三至四成重量，是皮革製程中最大宗的廢棄物之一。本試驗目的是希望能研發一種具備技術可行性的生物處理方法，取代目前常用的高溫焚化處理方式來處理廢棄的皮革肉膠。 本試驗首先利用胰蛋白酶大豆瓊脂 (tryptic soy agar, TSA) (pH = 12) 由皮革廠鹼性浸灰廢水中分離出嗜鹼性或可以耐鹼性環境菌株；再將剪成適當大小的肉膠塊放入培養皿中，接種20mL的分離純化後菌株菌液後置於30oC培養箱中培養，每日觀察並記錄其分解狀況。經過篩選後，最後選用分解肉膠效率最快的P菌株進行後續的試驗。 首先利用畜牧場牛糞活性污泥廢水反應槽進行肉膠分解液處理試驗，實驗結果顯示對生化需氧量 (BOD)、化學需氧量 (COD) 及懸浮固體 (SS) 平均去除率分別為81±4、60±8及55±6%。由此可看出畜牧場污泥可分解利用肉膠分解液，但COD去除率仍偏低，可能仍有部分有機質無法被畜牧場牛糞污泥所降解。 其次使用一公升的肉膠泥 (肉膠：水＝ 1：1) 做為基底，與所選用的菌株P之菌液200毫升，一起加入反應槽中進行肉膠活性污泥的培養，再利用此肉膠活性污泥反應槽進行肉膠泥連續分解，最後使用批次式反應槽 (Sequencing batch reactor, SBR) 來進行肉膠分解液的處理試驗。批次式反應槽 (SBR) 是一種利用活性污泥分解廢水中有機質的廢水處理設備，本研究所使用的活性污泥係利用肉膠直接在反應槽內連續曝氣培養而成。以肉膠活性污泥反應槽進行肉膠泥連續分解之實驗結果顯示，對BOD、COD及SS平均去除率分別為95.4±1.4、75.5±4.8及83.5±11.2%，均較使用畜牧場污泥時為高。當使用批次式活性污泥反應槽處理肉膠分解液時 (水力停留時間為5天)，對於BOD與COD平均去除率分別為93.3與65.9%。由前述實驗結果得知，經微生物充分分解後之肉膠分解液較易被降解，而使用肉膠活性污泥與菌株P之混合活性污泥對肉膠泥及肉膠分解液皆有較佳的分解效率，若配合SBR活性污泥反應槽使用，則可每日穩定處理肉膠。 關鍵字：肉膠、嗜鹼性微生物、批次式活性污泥法

Abstract After un-haring and liming processes, the raw hides will be fleshed to separate the hides and fleshing with alkaline moisture (pH = 12−13) in tannery industry. The yield of leather fleshing is about thirty to forty percent of raw hides weights in the leather progress. Objective of this study is to develop a technically feasible biological fleshing treatment approach can instead of fleshing incineration. All microorganisms for this study were isolated in the liming wastewater by the tryptic soy agar (TSA) (pH = 12) for selecting the alkaliphilic or alkaline-tolerant bacteria. The fleshing was cut into appropriated size in petri dishes and then inoculated with 20 ml culture suspension of the isolates. The inoculated petri dishes were then incubated at 30oC and degradation of the fleshing was observed once a day. The isolate, strain P, capable of degrading fleshing efficiently was selected as the sole inoculum for this study. First, fleshing liquid was treated in a dairy activated sludge reactor for investigating the feasibility of treating fleshing liquid by activated sludge system. The removal rate of the biochemical oxygen demand (BOD), chemical oxygen demand (COD), and suspended solids (SS) was 81±4, 60±8, and 55±6%, respectively. Therefore, the fleshing liquid can be treated by dairy activated sludge. When smashed fleshing (fleshing: water = 1:1) was ground and mixed with bacterial suspension of strain P. The smashed fleshing mixture was then put into an activated sludge reactor to enrich fleshing activated sludge. The activated sludge reactor inoculated with fleshing activated sludge was then applied to treat smashed fleshing solid and liquid separately. For smashed fleshing treatment, the removal efficiency of BOD, COD, and SS was 95.4±1.4, 75.5±4.8, and 83.5±11.2%, respectively. In coordinating with a sequencing batch reactor (SBR) (hydraulic retention time = 5 d), the removal efficiency of BOD and COD was 93.3 and 65.9%, respectively. Experimental results in this study showed that the SBR inoculated with fleshing activated sludge and bacterial suspension of strain P can treat fleshing liquid steadily and efficiently. Key words: Leather fleshing, alkaliphilic bacteria, sequencing batch reactor (SBR)