Determination of first flush criteria using dynamic EMCs (event mean concentrations) on highway stormwater runoff

Abstract

Recently the Ministry of Environment in Korea has developed the total maximum daily load program in accordance with the target pollutant and its concentration goal on four major large rivers. Since the program is largely related to regional development, nonpoint source control is both important and topical. Of the various nonpoint sources, highways are stormwater intensive land uses since they are impervious and have high pollutant mass emissions from vehicular activity. The event mean concentration (EMC) is useful in estimating the loadings to receiving water bodies. However, the EMC does not provide information on the time varying changes in pollutant concentration or mass emissions, which are often important for best management practice development, or understanding shock loads. Therefore, in this study a new concept, the dynamic EMC determination method, will be introduced to clearly verify the relationship between EMC and the first flush effect. Three monitoring sites in Daejeon metropolitan city areas were equipped with an automatic rainfall gauge and a flow meter for accumulating the data such as rainfall and runoff flow. The dynamic EMC method was applied to more than 17 events, and the improved first flush criteria were determined on the ranges of storm duration and accumulated rainfall.

Fate of Naphthalene in Laboratory-Scale Bioretention Cells: Implications for Sustainable Stormwater Management

“…The exit gas flowed through two ORBO activated carbon tubes (20/40 large charcoal, Sigma Aldrich) in series to capture any volatized naphthalene. From the activated carbon traps, the air was bubbled through two carbon dioxide traps (each contained 15 mL of 2 M NaOH) in series using fine bubble diffusers (Supelco) to capture any 14 CO 2 produced via naphthalene mineralization. An activated carbon tube was also affixed to the air input port to prevent any possible contamination from the ambient air in the room; this carbon tube was removed when adding water to the columns.…”

“…Sampling and analysis were conducted in an effort to account for all of the 14 C-naphthalene added to the system. Excess water leached through the column was collected from the leachate reservoir (Figure 1), weighed, and a subsample was analyzed for 14 C content. The activated carbon traps were sacrificed weekly, hexane-extracted, and the extracts were analyzed for 14 C content.…”

Assessment of cockle shells, walnut shells, and gingko shells as filter media for low impact development technologies

“…Generally, urban stormwater runoff contains 120.1-422.1 µg/L, 94.9-403.7 µg/L and 11.1-32.0 µg/L Cu, Zn and Pb, respectively. The main heavy metals contained in the general urban stormwater runoff are Cu, Pb and Zn [26]. In the biowaste filter media, the removal efficiency of Pb and Zn was about 40%-60%.…”

Appropriate Methods in Determining the Event Mean Concentration and Pollutant Removal Efficiency of a Best Management Practice

“…Continuous flow measurements were performed and rainfall data collected to obtain a relatively unbiased approximation of the pollutant mass loads. The total sampling time was adjusted to approximate the time during which the "first flush" was processed [10]. Generally, at least 12 samples were manually collected at both the inlet and outlet.…”