Impacts of coagulation on upflow roughing filtration in layers
Godfrey Mwiinga
Boikanyo Setlhare
R.E. Loewenthal
2134/29844
https://repository.lboro.ac.uk/articles/conference_contribution/Impacts_of_coagulation_on_upflow_roughing_filtration_in_layers/9595100
In community water supplies, technologies that are people-centred are encouraged to ensure sustainability. Upflow
roughing filtration in layers (URFL) is a simple pre-treatment process applied to reduce raw water turbidity without the
aid of coagulation to levels acceptable for effective slow sand filtration (SSF). However, practical applications of URFL
are limited to raw waters with turbidity < 20 - 50 NTU. Incorporation of simple coagulation, achieved by gravity dosing
equipment, can provide an opportunity for URFL to treat higher turbidity raw waters. This paper present results of a study
carried out on the impacts of low-dosage simple coagulation on URFL performance. The main evaluation criterion was the
effluent turbidity. Intermittent coagulation was studied as well, including its effect on, headloss and filter media cleaning.
The URFL unit was regularly challenged with high turbidity loads without adjusting coagulant dosages. Coagulation was
achieved with lower-than conventional dosages. URFL effluents were sent to SSF, whose effluent turbidity was analysed.
2018-02-12 15:09:12
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