Enhancing sedimentation by improving flow conditions using parallel retrofit baffles

• Published in: Journal of environmental management Vol. 160; pp. 1 - 6
• Main Authors: He, Cheng, Scott, Eric, Rochfort, Quintin
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.09.2015; Academic Press Ltd
• Subjects: Basins; Bioreactors; Comparative analysis; Enhanced sedimentation; Environmental management; Humans; Hydraulics; Increased residence time; Laboratory experiments; Retrofit baffles; Sedimentation & deposition; Waste Disposal, Fluid - instrumentation; Waste Disposal, Fluid - methods; Water Movements; Water Purification - instrumentation; Water Purification - methods; Enhanced sedimentation; Retrofit baffles; Increased residence time; Laboratory experiments
• ISSN: 0301-4797; 1095-8630
• DOI: 10.1016/j.jenvman.2015.06.013

In this study, placing parallel-connected baffles in the vicinity of the inlet was proposed to improve hydraulic conditions for enhancing TSS (total suspended solids) removal. The purpose of the retrofit baffle design is to divide the large and fast inflow into smaller and slower flows to increase flow uniformity. This avoids short-circuiting and increases residence time in the sedimentation basin. The newly proposed parallel-connected baffle configuration was assessed in the laboratory by comparing its TSS removal performance and the optimal flow residence time with those from the widely used series-connected baffles. The experimental results showed that the parallel-connected baffles outperformed the series-connected baffles because it could disperse flow faster and in less space by splitting the large inflow into many small branches instead of solely depending on flow internal friction over a longer flow path, as was the case under the series-connected baffles. Being able to dampen faster flow before entering the sedimentation basin is critical to reducing the possibility of disturbing any settled particles, especially under high inflow conditions. Also, for a large sedimentation basin, it may be more economically feasible to deploy the proposed parallel retrofit baffle in the vicinity of the inlet than series-connected baffles throughout the entire settling basin. •Flow uniformity is promoted using a retrofit parallel baffle array in a particle settling basin.•The large and fast inflow was divided into smaller and slower flows.•The performance of parallel and serial baffle configurations are compared.•A numerical model was used to obtain information which would be challenging to measure using physical methods.