Effects of calcined aluminum salts on the advanced dewatering and solidification/stabilization of sewage sludge.
Effects of calcined aluminum salts on the advanced dewatering and solidification/stabilization of sewage sludge.
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DOI：
10.1016/s1001-0742(10)60539-6
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发表时间：
2011-07
影响因子：
6.9
通讯作者：
Guangyin Zhen;Xiaofei Yan;Haiyan Zhou;Hua H. Chen;Tiantao Zhao;Youcai Zhao
中科院分区：
文献类型：
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作者：
Guangyin Zhen;Xiaofei Yan;Haiyan Zhou;Hua H. Chen;Tiantao Zhao;Youcai Zhao
污水脱水污泥中的高含水率（80%）是处置和回收利用的主要障碍。采用煅烧铝盐（AS）作为固化剂，CaCl_2、Na_2SO_4和CaSO_4作为促进剂，开发了污泥的化学脱水和稳定/固化（S/S）替代方案，以提高污泥的机械压缩性，使填埋操作成为可能。所得基质的性质进行了测定的含水量，无侧限抗压强度，水化产物，和毒性特性。结果表明，AS具有中等的火山灰活性，当AS质量分数为5%、CaS 04质量分数为10%时，制得的砂浆AS 0的含水率在50%~ 60%，养护5-7 d后的抗压强度为（51.32 ± 2.9）kPa，满足卫生填埋的最低要求。CaS_（04）的加入明显改善了S/S性能，提高了强度水平。X射线衍射、扫描电子显微镜和热重-差示扫描量热法研究表明，大量的水合物（即，石膏和CaCO 3）存在于固化污泥中，导致可蒸发水的消耗和强度的增强。此外，还进行了毒性特征浸出法（TCLP）和水平振动浸出法（HJ 557-2009）评价其环境相容性。结果表明，固化产物符合国家规定的毒性特征标准，可以进行卫生填埋处理。
The high moisture content (80%) in the sewage dewatered sludge is the main obstacle to disposal and recycling. A chemical dewatering and stabilization/solidification (S/S) alternative for the sludge was developed, using calcined aluminum salts (AS) as solidifier, and CaCl2, Na2S04and CaS04as accelerators, to enhance the mechanical compressibility making the landfill operation possible. The properties of the resultant matrixes were determined in terms of moisture contents, unconfined compressive strength, products of hydration, and toxicity characteristics. The results showed that AS exhibited a moderate pozzolanic activity, and the mortar AS0obtained with 5% AS and 10% CaS04of AS by weight presented a moisture contents below 50%–60% and a compressive strength of (51.32 ± 2.9) kPa after 5–7 days of curing time, meeting the minimum requirement for sanitary landfill. The use of CaS04obviously improved the S/S performance, causing higher strength level. X-ray diffraction, scanning electron microscopy and thermogravimetry-diiferential scanning calorimetry investigations revealed that a large amount of hydrates (viz., gismondine and CaC03) were present in solidified sludge, leading to the depletion of evaporable water and the enhancement of the strength. In addition, the toxicity characteristic leaching procedure (TCLP) and horizontal vibration (HJ 557–2009) leaching test were conducted to evaluate their environmental compatibility. It was found that the solidified products conformed to the toxicity characteristic criteria in China and could be safely disposed of in a sanitary landfill.