Related Experiment Video
Updated: Jun 28, 2026

Integrated Field Lysimetry and Porewater Sampling for Evaluation of Chemical Mobility in Soils and Established Vegetation
Published on: July 4, 2014
Aging effects on reactivity of an aluminum-based drinking-water treatment residual as a soil amendment
S Agyin-Birikorang1, G A O'Connor
1Soil and Water Science Department, University of Florida, 106 Newell Hall, P.O. Box 110510, Gainesville, Fl 32611-0510, United States. agyin@ufl.edu
Abstract:
Several studies have shown that drinking-water treatment residuals (WTR) could be used to control mobility of excess phosphorus (P) and other oxyanions in poorly sorbing soils. Presently, only "aged" WTRs (those left, or manipulated, to dewater) are land applied. However, if demand for WTRs increase in the near future, freshly-generated WTRs could be considered for land application. To our knowledge, few studies have examined the reactivity and equilibration time of freshly-generated alum-based WTR (Al-WTR). A laboratory thermal incubation study was, therefore, conducted to determine various extractable Al forms in Al-WTR as a function of WTR "age", and the time required for freshly generated Al-WTR to stabilize. Freshly-generated Al-WTR samples were collected directly from the discharge pumps of a drinking-water treatment plant, and thermally incubated at 52 degrees C, either with or without moisture control, for < or = 24 wk. Additional dewatered Al-WTR samples of various ages (2 wk- to 2 y old) were also included in the study. Various methods of extracting Al [total-, oxalate (200 and 5 mM), and Mehlich 1 extractants] were utilized to assess Al extractability over time. Freshly-generated Al-WTR samples were potentially more reactive (as reflected in greater 5 mM oxalate extractable Al concentration) than dewatered Al-WTR samples stockpiled for > or = 6 mo. Aluminum reactivity of the freshly-generated Al-WTR decreased with time. At least 6 wk of thermal incubation (corresponding to > or = 6 mo of field drying) was required to stabilize the most reactive Al form (5mM oxalate extractable Al concentration) of the Al-WTR. Although no adverse Al-WTR effects have been reported on plants and grazing animals (apparently because of low availability of free Al(3+) in Al-WTR), land application of freshly-generated Al-WTRs (at least, those with similar physicochemical characteristics as the one utilized for the study) should be avoided.
More Related Videos
Related Concept Videos
Acid Mine Drainage
Alkali Aggregate Reaction in Concrete
Toxic Reactions: Overview
Toxicity falls into two primary categories: local and systemic.
Local toxicity appears at the exposure site, such as protein denaturation caused by caustic substances.
In contrast, systemic toxicity requires the toxic agent's absorption and distribution,...
Effect of Sea Water on Concrete
Concrete in areas between tide marks, which undergo...
Retarders
The function of retarders is to delay the setting of concrete, and this effect can be measured using a penetration test. The retardation process involves adding...
Microbial Wastewater Treatment

