淨水污泥混合營建廢棄土製磚及燒結人造骨材的研究

Abstract

在經濟快速的發展下，台灣地區每年產生的淨水污泥與營建廢棄土節節上升。以往廢棄污泥以掩埋作為最終處置的方式已不符環保精神，為降低環境的負荷、有效的利用資源，將廢棄污泥資源化再利用是未來的處理趨勢。 本研究探討利用燒結處理，將廢棄污泥資源化，成為有價值的營建工程材料。首先對污泥的基本性質進行瞭解，並評估其燒結的特性，用以探討將淨水污泥與營建廢棄土混合燒結製磚的可行性。另外，為使淨水污泥再利用多元化、多適用性，進行燒結人造骨材的研究，期使燒結處理成為資源化淨水污泥之經濟、可靠、穩定的技術。 粉體分析顯示，淨水污泥成份中SiO2的含量偏低、Al2O3的含量偏高，至於營建廢棄土的成份則相當接近一般磚用黏土。淨水污泥的添加對燒結磚體的強度有負面的影響，在950℃的燒結溫度下，混合15%的淨水污泥抗壓強度只達到約100 kg/cm2。燒結溫度對磚體的強度影響很大，在1050℃的燒結溫度下，即使混合30%的淨水污泥，其抗壓強度依然可達到200 kg/cm2以上。另一方面，淨水污泥以1000℃、1050℃、1100℃製作燒結型人造骨材，其比重皆小於2。綜合比重、吸水率、抗壓強度的測試結果，淨水污泥燒結人造骨材與天然骨材相較，具有低比重、強度稍弱的特性，但符合作為輕質骨材應用的基本性質。

Although water treatment residual (WTR) contains no hazardous chemicals, the increasing volume generated from water treatment has reached unmanageable level. The soil excavated from the ground before construction, essentially clay, is another big problem in this island. Currently, landfill disposal is the main waste management method for these two waste soils, which is not a practical solution because of high cost of transportation and the scarcity in land. Due to the nature of WTR and excavation soil (ES), recycling and reuse in construction materials has become a more popular way of treating them. In this study, sintering processes were attempted to make the waste soils into building brick and artificial aggregate. First, the chemical compositions of WTR and ES were analyzed using ICP-AES and the mineralogical composition was determined with X-ray diffraction. The chemical composition of ES was similar to clay. WTR had more Al2O3 and less SiO2 than ES. The compression strength result suggested that sintering temperature was critical in brick-making. Various amount of WTR was added to ES before sintering, and the sintering behaviors of the products from different sintering conditions were monitored. When sintered at 1050℃, the brick from samples containing 30% WTR could reach around 200 kg/cm2 compression strength. Bricks made from mixtures containing 15% WTR could reach 100 kg/cm2 compression strength when sintered at 950℃. The specific gravities of artificial aggregates sintered at 1000℃, 1050℃, and 1100℃ were all less than 2 kg/cm3. Results of specific gravity, water absorption, and compression strength suggested that WTR artificial aggregate could meet the general requirement for lightweight aggregates.