Phosphorus Retention by Fly Ash Amended Filter Media in Aged Bioretention Cells

Abstract

Bioretention cells (BRCs) have shown potential for storm water quantity and quality control. However, the phosphorus (P) removal in BRC has been variable due to differences of soil properties in filter media. The objectives of this research were to identify and evaluate P accumulation in filter media and to quantify effluent P reduction in BRC. Each cell has a sand and fly ash media designed to remove phosphorous. Filter media were collected in 2014 across the cell surface and to a depth of 0.6 m to quantify the P accumulation. The mean total P (T-P) concentration increased over the seven years of operation, but the changes were not statistically significant. The average Mehlich-3 P (M3-P) and water-soluble P (WS-P) concentrations in the media profiles showed higher P accumulation in the top 0.15 m. The average M3-P and WS-P concentrations between 0.15 m to 0.30 m, and 0.30 m to 0.60 m were variable on all four BRCs media. The media with 5% fly ash significantly retained M3-P and WS-P over the top 0.15 m. Stormwater influent and effluent samples from three of the BRCs monitored over one year showed reductions in both P concentration (68% to 75%) and P mass (76% to 93%).

Effect of a Submerged Zone and Carbon Source on Nutrient and Metal Removal for Stormwater by Bioretention Cells

“…Previous studies have demonstrated that BCs implemented in relatively small catchments effectively improve both water quantity and quality in response to frequent storm events [9][10][11].In the vegetated filter media, pollutants from storm runoff can be removed through a variety of mechanisms, including physical, chemical and biological processes [12][13][14], and its quality is further enhanced by plant uptake and biological activities in the rhizosphere [15,16]. In recent years, research has shown that BCs can effectively improve water quantity and remove suspended solids [17,18], nutrients [19][20][21], and heavy metals [22,23]. However, it is difficult to meet or maintain a consistently satisfactory performance for reducing nitrogen due to a lack of effective denitrification [24,25].Since it is difficult to achieve consistent high nitrogen removal in standard stormwater bioretention systems, a submerged (anoxic) zone (SZ) combined with a module of BCs added carbon source (C) (e.g., wood chips, shredded newspaper, sawdust etc.)…”

Application of Fly Ash as an Adsorbent for Removal of Air and Water Pollutants

“…On the other hand, FA not only has the capacity to adsorb heavy metals from wastewater, but also has the ability to adsorb other organic/inorganic pollutants from wastewater, including to phosphorous, fluoride, boron, phenolic compounds, pesticides, dyes, etc. [5,151]. Phosphorus is an indispensable element in living organisms.…”

“…Many researchers [152,153] have studied the use of FA to remove phosphorus from wastewater. Kandel et al reported that mixture of sand with 5% of FA by weight can effectively reduce phosphorus concentration in water [151]. They showed that the FA has a good effect of adsorb or precipitate phosphate because of the FA contains a certain amount of calcium contents.…”

Field studies of pollutant removal from nursery and greenhouse runoff by constructed wetlands

“…For example, Wilson, Riiska, and Albano () found that 29% of chlorothalonil application in a nursery setting was deposited on the ground surface instead of in pots, which led to concentrations up to 500 μg L −1 in runoff, a level toxic to aquatic microorganisms (e.g., 96‐h LC 50 , the concentration that will kill half of a test population, for adult grass shrimp is 150 μg L −1 according to Key, Meyer, & Chung, ). Excess nutrients lead to algal blooms and are an ongoing challenge in both agricultural and urban runoff (Anderson, Gilbert, & Burkholder, ; Kandel, Vogel, Penn, & Brown, ; Paerl et al., ; Smith, ; Smith, King, & Williams, ; Watson et al., ).…”

“…The combination of frequent irrigation, (e.g., , the concentration that will kill half of a test population, for adult grass shrimp is 150 μg L −1 according to Key, Meyer, & Chung, 2003). Excess nutrients lead to algal blooms and are an ongoing challenge in both agricultural and urban runoff (Anderson, Gilbert, & Burkholder, 2002;Kandel, Vogel, Penn, & Brown, 2017;Paerl et al, 2016;Smith, 2003;Smith, King, & Williams, 2015;Watson et al, 2016).…”