污泥高速旋風乾燥減量之研究-以北部某水資源回收中心設施為例

The sludge reduction by a high-speed dewatering cyclone – a case study of a water resources recycling center in northern Taiwan

王偉漢(Wei-Han Wang)

指導教授 ： 陳孝行 ； 翁煥廷

國立臺北科技大學/工程學院/環境工程與管理研究所/碩士(2012年)

https://doi.org/10.6841/NTUT.2012.00154

摘要

下水道污水性質會因收集區域社區型態及土地使用分類而有所差異，流至各污水處理廠也會因處理流程、藥劑添加種類不同，所產生的污泥性質種類也會有差異性。據統計臺灣民生污水及工業廢水於污水處理過程所產生的污泥量總計每年約250萬公噸，其最終處置方式大多為衛生掩埋，如此將縮短掩埋場的使用年限，因此污泥減量在地狹人稠的臺灣已成為當今重要的環保議題。
本研究以北部某水資源回收中心為例，檢視其歷年污泥產生單元操作數據，對各污泥單元進行效能分析評估，以達污泥減量操作之目的。並由文獻探討污泥各種資源化再利用途徑，配合最終處置方式擬定污泥乾燥處理做為中間處理，評估並實測該水資源回收中心增設污泥高速旋風乾燥設備之效益，以供日後興建或改善污水處理廠參考。
研究結果顯示，該水資源回收中心污泥單元各項操作參數均於標準範圍內，處理效果良好，能有效控制污泥餅產生量，在進流水量水質變動幅度不大之情況下，污泥單元操作參數可不必隨之調整。
脫水污泥無混合經高速旋風乾燥後，污泥含水率可降至約20∼34％，減重率為63∼69％，進料污泥含水率高時，有較佳之含水率降低效果，且進料含水率對減重率的影響較進料速度的影響為大。當進料速度每小時100kg時，每噸污泥之乾燥淨效益為125.6元，隨乾污泥混合比增加會降低乾燥效益，乾污泥混合比超過40％時即無效益；若進料速度提升至500kg/hr，乾燥之效益可達1778.3元/噸，降低39.5％之污泥清運處理成本。
本研究亦以迴歸分析方法，推估經乾燥後理論減重率（減重率2，％）與實測減重率（減重率1，％）之關係式、乾燥後污泥含水率之預測模式並導出污泥乾燥效益之預測模式，所得結果分別為：
1. 減重率2（％）＝-3.24＋減重率1（％）× 0.965
2. 無混合乾燥污泥含水率（％）＝31.0846－0.0241 × 進料速度
（進料速度適用範圍：0∼500kg/hr）
3. 混合乾燥污泥含水率（％）＝30.9261－0.1916 × 乾污泥混合比（％）
（進料速度100kg/hr、乾污泥混合比適用範圍：0∼80％）
4. 無混合污泥乾燥效益（元/噸）＝71.84＋3.7328 × 進料速度
（進料速度適用範圍：100∼500kg/hr）
5. 混合污泥乾燥效益（元/噸）＝122.6829－3.1126 × 乾污泥混合比
（進料速度100kg/hr、乾污泥混合比適用範圍：0∼40％）
污泥乾燥減量效益對全廠營運成本的貢獻度極大，約可降低整廠營運成本6.32％，顯現污泥乾燥減量極具效益。

關鍵字

下水道污泥 ； 污泥含水率 ； 污泥乾燥 ； 效益分析

並列摘要

The wastewater characteristics of sewer present the variation due to different community types of collecting area and the classification of land application. Likewise, the sludge features of each wastewater treatment plant correspond to different treating processes and the types of additional chemicals. In Taiwan, the total amount of sludge yield is around 2.5 million tons per year from the municipal and industrial wastewater treatment plants. The sludge buried in landfill is the final disposal, which will shorten the usage life of the landfill. Therefore, the sludge reduction is one of the most important environmental issue in Taiwan with such high-density population.
In this work, a water resources recycling center in northern Taiwan was exemplified. The effectiveness of each sludge-treatment unit was evaluated by analyzing the sludge-operation parameters and characteristics data of sludge in order to achieve the goal of sludge reduction. In addition, we evaluated various resources-reuse techniques based on literatures discussion and associated to the final treatment approaches to propose the sludge desiccation as an intermediate treatment procedure. The sludge desiccation efficiency of a new high-speed cyclone in this center was assessed as the reference for the construction or improvement of wastewater treatment plant in the future.
Results indicated that the operational parameters of each sludge unit in this center were controlled under the standard range. This sludge system was able to control the yield of sludge cakes effectively. Hence, there was no need to adjust operational parameters when the quantity and quality of influent maintained at certain stable ranges.
After the desiccation of the high-speed cyclone, the water content of sludge was around 20%-34% (i.e., the removal rate of weight was 63%-69％). The high water content of sludge presented relatively high desiccation rate. In comparison with the feeding rate, the water content of sludge influenced the removal rate of weight more significantly. The cost-effectiveness of the desiccation process was NTD 125.6 per ton at the feeding rate of 100 kg/hr. The increase of sludge mixing ratio would decrease the cost-effectiveness of the desiccation process. When the mixing ratio was over 40%, there was no cost-effectiveness. If the feeding rate was enhanced to 500kg/hr, the cost-effectiveness of the desiccation process was achieved to NTD 1,778.3 per ton and the 39.5 % cost of sludge removal and treatment could be deducted.
By the regression analysis, the corresponding equation between the theoretical (removal 2, %) and practical removal rate of weight (removal 1, %) was developed. A predictive model was established to estimate the water content and the cost-effectiveness of desiccation sludge. Several conclusions were drawn as the following:

1. Removal 2 (%) = -3.24 + Removal 1 (%) × 0.965
2. The water content of desiccated sludge without mixing (%) = 31.0846 - 0.0241 × feeding rate (0-500kg/hr)
3. The water content of desiccated sludge with mixing (%) = 30.9261 - 0.1916 × mixing ratio (%) (feeding rate of 100kg/hr, mixing ratio 0% - 80%)
4. Desiccation effectiveness without mixing (NT dollar/ton) = 71.84 + 3.7328 × feeding rate (100-500kg/hr)
5. Desiccation effectiveness with mixing (NT dollar/ton) = 122.6829 - 3.1126 × mixing ratio (%) (feeding rate of 100kg/hr, mixing ratio 0% - 40%)

The cost-effectiveness of sludge desiccation contributes to the whole running-cost of wastewater treatment plant dramatically, which can eliminate 6.32% running-cost. This study demonstrated the applicable potential of the sludge desiccation procedure.

並列關鍵字

Sewer sludge ； Water content of sludge ； Sludge dewatering ； Effectiveness analysis

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