Innovative use of lamella clarifiers for central stormwater treatment in separate sewer systems

Abstract

Lamella settlers have been used in the past few years for the sedimentation of particles in wastewater and stormwater applications. A new and very innovative approach for the treatment of stormwater flows is proposed which extends the portfolio of solutions beyond traditional settling tanks. Surface runoff is stored in a sewer or a basin and finally treated in a small but continuously operated lamella clarifier. The low throughput flow will yield good treatment efficiency at a small footprint. The possibilities of using existing storage volume in a storm sewer, as well as the structural flexibility of the arrangement are decisive benefits. As a large operational advantage, the lamellae may be cleaned mechanically, e.g. by pivoting under water. Finally, the flow and the sludge which will be sent to the downstream treatment plant will be minimized. A new comparative simulation method is proposed in order to assess an equivalent degree of stormwater treatment, either by achieving an equal annual volume of treated stormwater or, more directly, an equal amount of spilled pollutant load. The new solution is compared with a traditional settling tank according to current German design rules. Additionally, a case study from a real installation will be presented.

Simulation and optimization of a lamella settler for cattle feedlot wastewater treatment and nutrients recovery. Experimental validation in the field

“…The achievable settling efficiency allows using units smaller than conventional settlers or sedimentation basins ( Getaz, 2018 ). Lamella settlers have been used for many applications as secondary clarifiers ( Tchobanoglous et al., 2014a , Tchobanoglous et al., 2014b ), stormwater treatment ( Fuchs et al., 2013 ; Weiss, 2013 ), dairy wastewater treatment ( Martín-Rilo et al., 2015 ), and other food industry installations ( Getaz, 2018 ). Despite many applications of lamella settlers, optimization for treating the feedlot wastewater would lead to better performance.…”

. Introduction to Wastewater Treatment

“…23. Lamella clarification (left) and types of lamella settlers: counter-flow (A), parallel flow (B),and cross-flow (C)[25]…”