Evaluation of Nutrients and Suspended Solids Removal by Stormwater Control Measures Using High-Flow Media

Abstract

High Flow Media (HFM) is able to treat large runoff volumes using smallfootprint systems. Seven full-scale HFM Stormwater Control Measures (SCMs) in a residential area were monitored over 11 months to assess the removal of Total Suspended Solids (TSS), Nitrogen, and Phosphorus in First Flush (FF) stormwater runoff. Excellent removal of TSS and particulate-bound nutrients was noted, but, in most SCMs, removal of dissolved species was limited. Sorption of dissolved P occurred, although most likely on captured and suspended sediment and not on the HFM itself. Mineralization and nitrification of dissolved N species during dry periods led to nitrate export. HFM grain size and organic content did not significantly impact TSS or P removal, but higher organic content was associated with higher N removal. FF was present in TSS (strongest), TN, and TP (weakest). Optimal HFM SCM design incorporates sedimentation before filtration.

A Review on the Application of Granular Filter Media and the Utilization of Agro-Industrial Wastes for Stormwater Quality Improvement

“…The total suspended solids (TSS) refer to the solid particles that remain in suspension within the water and are considered a significant cause of water quality deterioration. TSS inputs were highest when large rainfall events coincide with dryer antecedent conditions [24], whereas in other findings, the TSS influent from small rainfall events is statistically higher than large storms [29]. High TSS leads to aesthetic issues and would affect both ecological and aquatic environments.…”

“…The composition of stormwater runoff, quality, and quantity is highly variable in space and time as it has intermittent nature [28]. This stormwater quality fluctuates and is influenced by the interrelation of several factors, primarily by heavy precipitation [2], runoff that is generated irregularly [17], rainfall duration, antecedent dry days, landuse [29], the surface type and imperviousness, atmospheric and climate conditions, total population, waste disposal practices, the construction activities and rapid urbanization. For instance, the stormwater quality from relatively clear surfaces, such as a rooftop, is generally better than the one that flows over heavy traffic roads.…”

“…For instance, the stormwater quality from relatively clear surfaces, such as a rooftop, is generally better than the one that flows over heavy traffic roads. The stormwater runoff is more polluted during the first flush [29]. Contamination from the upstream drainage directly affects receiving water bodies [30], and there is a higher potential for pollutant accumulation during long dry periods [31].…”

“…Then, the addition of chemicals is made during coagulation before continued with the flocculation and sedimentation stage. Sedimentation before filtration minimizes clogging concerns [29]. Then, the disinfection process is applied to reduce microorganisms.…”

Importance of the Submerged Zone during Dry Periods to Nitrogen Removal in a Bioretention System

“…Bioretention system, also known as rain garden, biofiltration or biofilter, is a typical low impact development (LID) facility to purify runoff through the combined action of plants, soil media and microorganisms [1,2]. It has been proved to be effective for the removal of most pollutants in runoff, such as heavy metals [3,4], suspended sediment [5][6][7], grease [8], pathogenic bacteria [9,10], etc. However, many previous studies indicated that bioretention systems have a low and unstable nitrogen removal rate [11,12], especially of NO3 --N. Sometimes even nitrogen "leaching" occurred [13] in the systems.…”