Effectiveness of combined up-flow roughing filter and up-flow slow sand filter to reduce turbidity in Citarum water as a source of drinking water

Abstract

The turbidity of the Citarum River was high, fluctuating, and used as a drinking water source by PDAM (Regional Drinking Water Company). This study aimed to determine the ability of a combined up-flow roughing filter (URF) and an up-flow slow sand filter (USSF) in reducing turbidity, called multistage filtration (MSF). MSF was varied with and without settlers. Gravel diameters and perviousness: 0.5 cm was 0.243, 1 cm: 0.264, 2 cm: 0.265, 5 cm: 0.302 or 24-30% of URF’s volume. When settler was run with surface loading 0.5 m3/m2/hour, flowrate 0.67 l/minute, turbidity 321.16-3,496.53 NTU, the efficiency was 57.9-96.2%. Settler reduced turbidity significantly. URF1 enhanced turbidity removal. However, URF2, URF3, USSF were not effective. In an experiment without a settler, turbidity 130.78-533.00 NTU, but its reduction in URF1 was bad. In URF2 turbidity was almost the same as in the experiment with the settler. Efficiency was 41.9-89.1%. Here URF1 and URF2’s functions were almost the same as settler and URF1. URF3 was ineffective, can be removed. USSF was needed even though only able to reach 10-25 NTU. URF and USSF contributed to the higher efficiency of turbidity removal.

Gallery well application as a media for water treatment in flooded areas (case study: Morowudi Village, Gresik Regency)

“…Figure 5 shows the effectiveness of reducing the total number of coliforms reached more than 85% of a large number of bacteria. This is because the presence of geotextiles helps increase the number of bacteria, where this geotextile has a surface structure that is almost the same as the surface structure of a sand filter as well as its pores [7] so that filtered bacteria can grow on it. In addition, adding geotextiles can expand the surface area for the attachment of bacteria.…”

“…The continuous flow of water causes the thickness of the biofilm layer to form, causing the media pores to become clogged and increasing the decomposition products. Geotextiles made of PET or PP are hydrophobic, so suspended particles carried in raw water can trap microorganisms where the matrix formed between geotextile fibers is affected by variations in pore size [7]. The existence of geotextiles is quite helpful in growing the schmutzdecke layer because of its sand-like structure, which can increase the number of bacteria in the filter bed [9].…”