Evaluation of silt curtain in the reduction of suspended solids

Turbidity curtains, also called as turbidity barriers and silt curtains, were designed to contain plumes of suspended solids in water bodies. The high concentration of suspended solids in the raw water impacts on the costs of its treatment. Water with higher turbidity requires more coagulants in water treatment and needs a sludge management. In order to reduce turbidity in the water intake, the present study used a central composite rotational design (CCRD) for a set of 2 in-line turbidity curtains in a laboratory hydraulic flume. Three factors were analyzed: the grammage of the first barrier, the grammage of the second barrier and the solids application rate. The experimental design was made of 18 experiments. Furthermore one blank test was performed. The analyses of variance revealed which factors were significant for each answer. The first curtain efficiency was related positively with the first grammage and negatively with the second curtain grammage. The second curtain efficiency was related positively with the second grammage and application load, and negatively related with the first grammage. The system retention mass was influenced positively by the application load.