A study on the performance of limestone roughing filter for the removal of turbidity, suspended solids, biochemical oxygen demand and coliform organisms using wastewater from the inlet of domestic wastewater oxidation pond
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Date
2006
Authors
U Han, Thein Maung
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Abstract
The original purpose of roughing filtration is to protect slow sand filters by
reducing influent turbidity and suspended solids to a level that is effective for operation.
Roughing filtration presents a promising method for improving raw water quality without
using any chemicals. Roughing filter is not only used to protect slow sand filters but
also for the treatment of wastewater before it is discharged to the environment or
reused.
The aim of this research is to study the capabilities of limestone roughing filter
for the removal of turbidity, suspended solids, biochemical oxygen demand and
coliform organisms. This study involved four different batches of experiments. Each
experiment used different sizes of limestone filter media, such as small size (1.91 mm),
medium size (4.9 mm), large size (16.28 mm) and a combination of those filter media
respectively. Wastewater from the influent of oxidation pond was used as water
samples in this experiment and it was passed through the roughing filter at six different
flow rates. Both unfiltered and filtered water samples were collected and tested at the
Environmental Engineering Laboratory of Universiti Sains Malaysia.
The experimental results indicate that roughing filter has an average turbidity
removal of 74.6% to 92.1%, suspended solids removal of 79.3% to 88.2%, coliform
organisms removal of 67.4% to 96.1% and BOD removal of 51.3% to 67.2%.
The removal efficiency of limestone roughing filter depends on the size of filter
media and applied filtration rates. The bigger size filter media gave the lower removal
efficiency than smaller filter media. At lower flow rate, the removal efficiency was higher
than at higher flow rate. Removal efficiency increased when the filter media was
covered with dirty layer called biofilm.
Overall, roughing filtration is an appropriate technology for the treatment of
wastewater because it could reduce coliform organisms and organic solids from
wastewater, before it is reused or discharged.
Description
Master
Keywords
Civil Engineering , Limestone , Coliform organisms , Wastewater oxidation pond