McMichael, P S; Iglesias, M C; Johnston, J; Holley, P and Peresin, M S (2025) Case study of bio-based coagulation and flocculation systems to treat contaminants in concrete washout water. International Journal of Construction Education and Research, 21(3), pp. 371-381. ISSN 1557-8771
Abstract
Concrete washout water is regularly generated in large volumes at construction sites across the world, often by the clean-up process for concrete pumps. This washout water is highly alkaline and contains high levels of heavy metals and solids. To treat suspended solids, it is often flocculated using polymeric flocculants or bentonite clay. In this pilot study, the potential use of a bio-based polysaccharide, citrus pectin, was investigated as an alternative flocculant and neutralizing agent. Pectin derived from orange peels was coupled with citric acid to test for efficacy in neutralization and flocculation. A variety of acid and flocculant combinations were analyzed through the measurement of suspended solids, dissolved solids, pH, and turbidity. Compared to bentonite, citrus pectin was found to have comparable flocculating capabilities, though citric acid was found to inhibit flocculation for both materials. The results demonstrate that pectin could serve as a bio-based alternative to existing commercial concrete washout water flocculants, an important distinction and addition to previous studies in the body of knowledge that did not utilize the much more turbid and solid-heavy concrete washout water. Such potential solutions could have a meaningful impact on improving jobsite logistics, time, and expense with respect to compliance and sustainability.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | alkalinity; cement; concrete washout water; flocculant; pectin |
| Index terms: | metal, agent, case study, body of knowledge, construction site, compliance |
| Subjects: | health safety and environment, practitioner, work location, traditional and composite building materials, knowledge management, data collection methods |
| Topics: | Site Management, Roles and Professions, Construction Materials, Health and Safety, Information Management, Research Practice |
| Descriptive scope: | 3 PCE |
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