固定式生物程序之污泥產率研究

Abstract

傳統式活性污泥法為在廢水處理中最廣泛使用的生物處理方法，其可利用微生物可效地去除水中溶解性有機物，但由於傳統式活性污泥法會產生大量之廢棄物，造成後續處理之問題。 固定化生物處理技術為一種可同時去除COD及氨氮之生物處理方法，且固定化細胞具有高機械強度與耐久性穩定性高、操作簡易等特性，但對於其污泥產率(sludge yield)仍尚未進行研究，因此本研究以固定化細胞處理技術搭配不同實驗參數(污泥粒徑、水利停留時間、曝氣模式)進行污泥產率之研究。 利用合成廢水(COD：300 mg/L，總氮：25 mg/L)，配合不同粒徑之固定化細胞(1 cm及2.5 cm粒徑)、不同曝氣模式(連續曝氣、1小時曝氣/1小時不曝氣、1小時曝氣/2小時不曝氣)及水力停留時間(6小時及12小時)進行實驗，其COD去除率均可達92.3%以上；總氮去除率約介於22.9~64.8%。於污泥生長係數方面，以1 cm粒徑之污泥粒，搭配連續曝氣(10 L/min)及12小時之水力停留時間所得到之污泥產量較低，其污泥生長係數為0.107 kg SS/kg COD，其餘則介於0.11~0.275 kg SS/kg COD。 於高COD之合成廢水(COD：1000 mg/L，總氮：25 mg/L)搭配連續曝氣及12小時之水力停留時間進行連續一星期之試驗方面，其結果得知，COD平均去除率為94.6%，總氮去除率約99.6％以上；於污泥生長係數方面，1 cm之污泥粒為0.228 kg SS/kg COD，2.5 cm之污泥粒為0.270 kg SS/kg COD。 本研究另採取食品廢水 (TCOD 773 mg/L，SCOD 556 mg/L，NH3-N平均13.2 mg/L，NO3-平均1.3 mg/L) 搭配連續曝氣及12小時之水利停留時間進行連續一星期之測試，結果發現，COD之平均去除率達89.4%，總氮去除率達95.9％以上；於污泥生長係數方面，1 cm之污泥粒為0.018 kg SS/kg COD，2.5 cm之污泥粒則為0.047 kg SS/kg COD。

The conventional active sludge process is the most widespread used biological treatment in wastewater treatment plant, which uses microorganisms to remove the soluble organic matter effectively in water. However, the conventional active sludge process will emit a large amount of wastes and produce problems to the following treatment processes. The Immobilized biological treatment is a technology simultaneously to remove COD and ammonia nitrogen and the immobilized cell has high density mixed microbial cells, high stability and durability, low effluent suspended solids, a short start-up period and easy to restart the operation but no studies have been focus on sludge yield of immobilized biological treatment yet. Thus, this study used immobilized cell processing technology with different experiment parameter (sludge particle size, hydraulic retention time, and aeration mode) to study the sludge yield. The lab scale immobilized biological treatment process is fed by synthesis wastewater to provide COD：300 mg/L and NH3-N：25 mg/L, with different particle size of immobilized cell (1 cm and 2.5 cm), different aeration mode (continuous aeration, 1 hour aeration/1 hour non-aeration, 1 hour aeration /2 hours non-aeration) and different hydraulic retention time (6 hours and 12 hours). The SCOD removal efficiencies can reach more than 92.3% and the total nitrogen removal efficiencies approximately is situated between the rate of 22.9~64.8%. Moreover, sludge yield is low, 0.107 kg SS/kg COD, for 1 cm particle size of immobilized biological treatment with continuous aeration (10 L/min) and 12 hour hydraulic retention time, the rest were between 0.11~0.275 kg SS/kg COD. As for the high COD concentration of synthesis wastewater (COD：1000 mg/L, NH3-N： 25 mg/L) with the continuous aeration mode and 12 hour hydraulic retention time carries continuously a week of experimental aspect, the results show that the average COD removal efficiency is 94.6% and total nitrogen removal rate is approximately above 99.6%. In addition, the sludge yield of 1 cm particle size is 0.27 kg SS/kg COD, and 2.5 cm particle size is 0.27 kg SS/kg COD. On the other hand, this research also adopts food industrial wastewater which concentrates 773 mg/L of TCOD, 556 mg/L of SCOD, 13.2 mg/L of NH3-N, 1.3 mg/L of NO3-N with the continuous aeration mode and 12 hour hydraulic retention time carries continuously a week of experiment aspects, the results show that the average COD removal efficiency is 89.4% and the total nitrogen removal rate can reach more than 95.9%. The sludge yield of 1 cm particle size is 0.018 kg SS/kg COD and 2.5 cm particle size is 0.047 kg SS/kg COD.