Investigation of selective filtration characteristics of filter media for pavement runoff treatment

Evaluation of Particulate Matter Capture and Long‐Term Clogging Characteristics of Different Filter Media for Pavement Runoff Treatment

“…Considering that a large amount of runoff with stable and consistent characteristics was required for the laboratory test, synthetic runoff was prepared as an alternative, according to the previous investigation results of the in situ pavement runoff [13]. Synthetic runoff was prepared by dissolving pavement deposited dust and chemical compounds into deionized water.…”

“…Five typical types of filter media used in filtration systems were chosen for this study, which were Zeolite, Ceramsite, Slag, Diatomite, and Vesuvianite. ey possess various porous structures and compositions (Figure 3) and can capture particulate matter by retention and/or absorption, along with some other physical and chemical interactions [13]. Besides, three different grain sizes of 1-3 mm, 3-6 mm, and 6-8 mm, which are widely applied in engineering projects, were also prepared for each filter medium.…”

“…e constant hydraulic head of 10 cm was maintained throughout the test by opening the overflow valve which was 10 cm above the top surface of the media. In order to eliminate its effect on the filtration process, flow rate was controlled at the constant level of 4 L/min in this study, according to the moderate daily rainfall in Yangzhou city [13]. Effluent from the outlet of each test was collected to analyze the TSS concentration, so that the index of removal rate can be calculated by (2) for different filter media.…”

“…Unfortunately, those systems are prone to clogging, leading to deterioration in (in)filtration capability [7,12]. Filtration and infiltration systems are normally filled with specified filter media (Figure 1), such as Zeolite, Diatomite, expanded vermiculite, Ceramsite, Vesuvianite, furnace/steel Slag [13], and granular activated carbon [14], along with conventional filter media such as soil, sand, and gravel. e pore structures of filter media will be blocked gradually as the suspended PM is captured [15][16][17][18].…”

“…e PM in pavement runoff originates from road-deposited sediments accumulated on the pavement surfaces, which will be washed off during rainy days [13]. e concentration and the particle size distribution (PSD) of PM are highly related to the clogging phenomenon.…”