Study of water treatment sludge incorporation into interlocking concrete pavers

ABSTRACT The sludge generated in the water treatment plants is the result of several operations that aim the adequacy of water to the legal standards of potability. Although there are alternatives for water treatment sludge, the usual final disposal solutions, as direct discharge into watercourses, still represent large impacts and overload the systems involved. The present paper aims to evaluate the technical viability of the incorporation of sludge from water treatment plants into interlocking concrete pavers. The influence of sludge moisture on the concrete behavior was also evaluated. Interlocking concrete pavers with cement mass contents of 2.5%, 5.0% and 7.5% of sludge at its natural moisture and 5.0% of dried sludge were evaluated by tests of compression strength, tensile strength by flexion, voids index, water absorption and density. The results showed that contents of up to 5.0% of addition do not generate significant changes in the properties of the concrete. Therefore, it would be possible to add sludge from water treatment plants in on interlocking concrete pavers, since limited to low levels. The incorporation of industrial waste into building materials is a viable alternative to minimize the environmental liabilities resulting from processes of production and treatment of other materials.

摘要：水处理厂产生的污泥，是为使水质符合饮用水卫生安全法定标准而开展的多项水处理工序的副产物。尽管针对水处理污泥存在多种处置方案，但诸如直接排入水体这类常规最终处置方式仍会造成严重环境影响，并给相关处置系统造成超负荷运行负担。本研究旨在评估将水处理厂污泥掺入联锁式混凝土铺路砖（interlocking concrete pavers）中的技术可行性，同时考察污泥含水率对混凝土性能的影响。本研究针对以下多组试样开展抗压强度、弯曲抗拉强度、空隙率、吸水率及密度测试：天然含水率污泥掺量分别为水泥质量2.5%、5.0%和7.5%的联锁式混凝土铺路砖，以及掺加5.0%干化污泥的联锁式混凝土铺路砖。测试结果表明，当污泥掺量不超过5.0%时，不会对混凝土的各项性能造成显著改变。因此，在将污泥掺量控制在较低水平的前提下，可将水处理厂污泥应用于联锁式混凝土铺路砖的生产中。将工业废弃物掺入建筑材料中，是减轻其他材料生产与处理过程所引发的环境负担的可行方案。