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原文传递 Systematic Evaluation of Polyacrylamide for Sediment and Turbidity Control.

题名：	Systematic Evaluation of Polyacrylamide for Sediment and Turbidity Control.
作者：	MCLAUGHLIN, R. A.
关键词：	Sediments-; Turbidity-; *Erosion-control.;Soil-stabilization; Construction-sites; Temperature-effects; Water-flow; Basins-; Gypsum-; Design-; North-Carolina; Runoff-; Evaluation-.
摘要：	An evaluation of polyacrylamides (PAM) for sediment and turbidity control for construction sites was conducted in both the laboratory and the field. Field tests of PAM logs were conducted to determine the effects of log condition (wet or dry) and water temperature on turbidity reduction in sediment basins. Basin design features, including baffles and outlet type, were also tested for optimal effectiveness with PAM. An alternative system, involving injecting PAM solution into turbid water flowing to different types of sediment bags, was tested under simulated runoff conditions. Finally, a laboratory screening was conducted for seven PAMs on eight sediment sources from North Carolina Department of Transportation (NC DOT) construction sites around North Carolina. The results indicate that the PAM logs were usually much less effective when initially dry at the start of the 25 min simulated storm event. The turbidity was higher with lower water temperatures, mostly likely due to increased water viscosity as opposed to reduced PAM release from the logs. The optimal basin configuration for maximum turbidity reduction using PAM included porous baffles made of a jute/coir combination. The outlet type did not significantly change the turbidity reduction by PAM. Sediment bags were tested with and without PAM injected as a solution and always had reduced turbidity with PAM. Less porous bag materials had lower turbidity in discharge but also clogged more quickly. For a Piedmont soil, the addition of gypsum generally increased turbidity at low PAM concentrations (<1,gL(sup -1)) for five PAMs with varying properties. The optimal PAM concentration was usually close to 1 mg L(sup -1) and higher doses tended to increase turbidity, but this effect was dampened when gypsum was added. This combination of effects suggests that the gypsum was competing with suspended sediment for binding sites on the PAM molecules. In contrast, several Coastal Plain soils responded to PAM only in the presence of gypsum. There was no soil property which correlated with this gypsum response in all soils, but sand content and extractable Fe were the most highly correlated.
报告类型：	科技报告