Frequently Asked Questions
- BMPTrains has a media called IFGEM. Where is it now?
ICS Media is the new name for IFGEM. Some BMPs have had name changes in the last 5 years. BMPTrains is simply out of date in some ways with current practice. More than a simple name change, BMPTrains is not fully consistent with the assessment of annual performance specified in the new regulations. The name IFGEM media was changed to ICS in 2022 to reflect the more transparent composition of Iron, Cay, and Sand. The composition and performance information for ICS is the same as identified by research and data under the name of IFGEM. - Were there changes to the calculation of life expectancy for any of the media?
The annual removal using sand was increased from 20 to 30%. An important change for all media was to allow for removal by upstream BMPs (not done in BMPTrains) and to allow flexibility to include or exclude it, as there is now an input cell in BMPFast for upstream removal. Also, there is an input cell for the inclusion of base flow (non-runoff). A media which removes dissolved phosphorus in non-runoff water has a reduced life expectancy if only treating runoff water. Both upstream removal and base flow were considered in BMPTrains life expectancy calculations. The parameters on media performance, such as weight and removal, have not changed. - Are there additional life expectancy removal test information and references for ICS media?
ICS media was tested under expected water quality conditions and the location of the filter after wet detention. A location for which physical removal is minimal. Thus, the nutrient removal was primarily chemical and biological. Biological removal of nitrate was noted due to low DO conditions, meaning both chemical and biological removal were present. Thus, dissolved phosphorus is selected for life expectancy because of the predictability of removal by chemical means and minimal complications from biological removal. Removal rates of up to 2.542 mg OP/gram of media were recorded under expected operating conditions. Adsorption testing was completed and published (Elhakiem, AIChe).
Based on the conditions of DO, pH, and Temperature, a removal rate per gram of media was selected. The selected value of 0.6 mg OP/gram of media is the maximum dissolved phosphorus removed per gram weight of media. This also assumed a treatment rate safety factor of 2.
References:
Hanan Elhakiem, 2019, “Adsorption Capacity Assessment of Advanced Green Environmental Media to Remove Nutrients from Stormwater-Runoff”, Electronic Theses and Dissertations. 6782. https://stars.library.ucf.edu/etd/6782.
AIChe, by NiBin Chang, Dan Wen, and Martin P. Wanielista, 2018, “Impact of Changing Environmental Factors and Species Competition on Iron Filings-Based Green Environmental Media for Nutrient Removal in Stormwater Treatment”, Environmental Progress & Sustainable Energy DOI 10.1002/ep (John Wiley online library). - Can the annual removal for a media tested with “raw” stormwater (no pre-BMP) be used for the annual removal after wet detention?
Test data are needed to support all media removal claims for the location used. Normally, removal rates for untreated (pre-BMP) stormwater are higher because of the physical filtration in addition to chemical and biological filtration. Noted is the use of ECT3 media as it has a filtration removal as well as a chemical and biological removal. - We are finding that media is one BMP that can be used to increase removal to meet the performance specifications of the new rule, but having to justify the use to some. What are the test data and references used for the removal using the B&G CTS media?
It Is extensive and follows unwritten guidance for approval and varies within and between the review agencies.
Note the following information for this FAQ was done in September 2025 and was originally submitted to support an ERP permit in August 2023. The 2023 report was modified to add information on influent concentrations.
Preface: This is a historical accounting of laboratory and field activities used to document the annual removal effectiveness of Bold & Gold™ Clay Tire crumb and Sand (CTS) pollution control media. Laboratory analyses were first completed to assess the sorption capacity of nitrogen and phosphorus as well as the biological removal of nitrogen. Tire chips had been approved by the Florida Department of Health for on-site wastewater treatment drain fields, nevertheless, EPA toxicity was assessed before field use of Bold & Gold™ CTS. A thesis was completed (Baldassari, 2007) to evaluate conditions for lethal concentrations using distilled water as well as stormwater detention pond water. In addition, Marinco Bioassay Laboratory in 2009 and 2019 was used to determine the presence of lethal concentration for 50% kill (LC50) with high nutrient concentrations like those in wastewater, as well as stormwater. No toxicity was noted. Field sites were then used under the sponsorship of regulatory and local agencies, and average annual performance was documented using composite sampling events over one year. The results of these published research reports on average annual effectiveness follows.
Purpose: The following provides information to document nutrient removal effectiveness when using Bold & Gold™ CTS media. Specifically provided are results of laboratory and field measurements that confirm the use of 75% removal of Total Nitrogen (TN) and 95% removal of Total Phosphorus (TP) when using Bold & Gold™ CTS 24 (2-feet deep) media; and 60% removal of TN and 90% removal of TP when using Bold & Gold™ CTS 12 (1-foot deep) media.
Background: Since the early 1970’s, media removal effectiveness in the State of Florida were documented by published results from laboratory experiments and actual operation of permitted field sites. For the last few years, the State DEP has been conducting an evaluation of stormwater management regulations to continue documenting effectiveness of BMPs. There continues to be reliance on published reports. These reports help in developing measures of effectiveness and to seek information so that a greater understanding of the measure of effectiveness evolves. This evolution is taking place in hope that a clearer understanding of how effectiveness is calculated. Removal data from laboratory and field measurements must be made available and it is considered best to present them in refereed publications and local or state agency field derived data and reports. These measurements and publications were done using B&G™ CTS media. They inform the consulting and regulatory communities in the State of Florida of the laboratory and full-scale testing. With these publications and reports, the regulators and reviewers can make more informed and defensible decisions.
Publications are found in the reference section below that support nutrient removal using B&G™ CTS media. Excerpts from these publications are emphasized in this document. This information is used to support the design, operation and effectiveness measures. Data in the referenced publications and other additional publications indicate the preponderance of information to support nutrient removal using B&G™ CTS sand-based sorption media.
Laboratory Work: A basic science and engineering question of interest is why some materials remove more nitrogen and phosphorus than others? Experiments for the kinetics of removal were conducted on 21 material classifications readily available in Florida (Wanielista et. al. 2008, Hossain, et.al. 2009, Chang, et.al. 2010). These included natural soils as well as recycled materials. Clay soils and some recycled materials were identified as candidates for removal of nutrients. From this laboratory research, materials in B&G™ media were further evaluated to determine the availability and cost for using various mixes. The materials in B&G are able to increase sorption capacity (more important to phosphorus removal) as well as soil moisture retention (more important for nitrogen removal) while providing sufficient infiltration for stormwater volume control (O’Reilly et al. 2014). Tire crumb and clay in B&G behave as an effective sorption material to increase the sorption capacity, especially phosphorus adsorption (Wanielista et al. 2008), while the silt and clay provided high moisture retention capacity which make contributions for forming a more favorable anoxic condition that enabled the progression of biogeochemical processes toward denitrification (O’Reilly et al. 2012).
Removal of Phosphorus as Soluble Reactive Phosphorus (SRP) was measured from a A3 sandy soil and from B&G™ CTS24 media using laboratory columns (6-inch diameter and at least 24 inches (2 feet of media)). The results showed CTS24 media effluent concentration was 96% lower than that from sandy soil (Figure 20, FDOT, 2013). SRP is used for removal since particulate phosphorus is most likely near 100% removed by sedimentation as in a wet detention pond. The average effluent concentrations of SRP were 180 and 7.655 µg/L from the Type A-3 sandy soil and the CTS24 media, respectively. Groundcover consisting of sod was used in the pilot studies and the CTS24 media reduced the leaching of OP from the sod. The laboratory testing of media mixes was conducted with a loading rate of at least 5 inches per hour so that there was no bypass of the media. Influent concentrations were similar to those found in stormwater. The media was further demonstrated for used in filters after wet detention ponds and in swales.
Dissolved Organic Nitrogen (DON) is sometimes present in waters that have been retained for long periods of time, such as days. If DON is present in the source water, CTS media has been demonstrated in laboratory column studies to remove DON. Expected removals are reported in the publications by Valencia (2020) listed below. Based on three laboratory column studies with DON being approximately 38% of the total nitrogen and three TN influent concentrations of approximately 1.5, 1.8 and 2.3 mg/L, the average DON removal using CTS was about 69%.
Field Work: To further support claims of nutrient removal, data were collected for water quality removal performance at the Hunters Trace (HT) retention pond for documentation of B&G ™ CTS12 (12 inches deep) media performance using multi-agency support (Wanielista, et.al. 2011). To examine soil mixtures as a media, measurements of soil properties and the removal of nitrogen and phosphorus were conducted at two ponds, one is HT, in Marion County, Florida. The other was a slow-infiltrating pond in Marion County. From the two Marion County stormwater infiltration ponds, an understanding of soil properties showed the value of the constituents of B&G™ CTS media for nitrogen and phosphorus removal and the installation of B&G ™ CTS media. The results were presented in the journal of Environmental Quality (O’Reilly, A. M. et.al., 2012). From this refereed publication, a sandy soil with a low percentage of clay (<5% by volume) may be used to remove nitrogen and phosphorus while still infiltrating or treating stormwater. The following quote is from the abstract of that publication: “Substantially different biogeochemical processes affecting nitrogen fate and transport were observed beneath two stormwater infiltration basins in north-central Florida. Differences are related to soil textural properties that deeply link hydroclimatic conditions with soil moisture variations in a humid, subtropical climate. During 2008, shallow groundwater beneath the basin with predominantly clayey soils (median, 41% silt + clay) exhibited decreases in dissolved oxygen from 3.8 to 0.1 mg L–1 and decreases in nitrate nitrogen (NO3–N) from 2.7 mg L–1 to <0.016 mg L–1, followed by manganese and iron reduction, sulfate reduction, and methanogenesis. In contrast, beneath the basin with predominantly sandy soils (median, 2% silt + clay), aerobic conditions persisted from 2007 through 2009 (dissolved oxygen, 5.0–7.8 mg L–1), resulting in NO3–N of 1.3 to 3.3 mg L–1 in shallow groundwater.” The results show around 99% removal of NO3-N when significant amounts of clay are present. Thus, a media with clay has the potential to remove nitrogen, but an acceptable infiltration rate is necessary to recover the treatment volume to store and treat runoff from the next runoff event. Water quality sampling of the HT pond was done before and after the addition of the Bold & Gold ™ CTS 12 media. An international publication documented the science and removal of nutrients in the HT pond (O’Reilly, 2011). The full-scale field BMP was implemented at the HT pond in 2009 and water-quality and hydrologic monitoring were conducted in 2009–2010. The removal of Total Dissolved Phosphorus (TPD) was between 70-90% for all samples. At this site, most of the particulates containing TP and TN were removed. The particulate fraction of TP was 60% and using 80% removal of TPD, the removal of TP was 92% (0.60 x 100 + 0.40 x 80). The removal of nitrate ranged from 50-80% for all samples. The particulate fraction of TN was 20% and using 65% removal of nitrate, the removal of TN was 72% (0.20 x 100 + 0.80 x 65). B&G™ CTS media. Composite sampling of an event was used over the period of a year for both the natural condition as well as for the media augmented condition.
Using a two-feet deep Bold & Gold ™ CTS media for a retention pond located at SW 85th street in Marion County, Florida, Shane Williams (2015) compared removal at the 1’ and 2’ depths. For CTS24 (2’ depth), TN removal was 73% and 50% at the 1’ depth.
Using two feet of B&G™ CTS media in a dual use filter treating excess reclaimed wastewater and stormwater (Wanielista, 2018) in the DeLand Rapid Infiltration Basin, the TN removals were 83% when treating reclaimed water and 95% when treating stormwater. Most of the nitrogen in wastewater and stormwater was in the form of nitrate at an average of 3.61 mg/L and 0.303 mg/L respectively. Composite sampling was again used for the loading for each event over a year and the stormwater loading over a 4-month period of time. The inlet total phosphorus average concentration for the wastewater was 3.76 mg/L, or much higher than that found in stormwater, and thus not considered as representative of stormwater.
For a dual-use filter below a swale along Highway 26 near Trenton, Florida, both groundwater during non-runoff conditions and highway runoff during storm events were treated for nitrogen removal (Wanielista, 2018 and FDOT, 2018). A CTS24 filter was shown to be effective for high concentrations of nitrate (average of about 5.7 mg/L) in the groundwater as well as the removal of TN from the highway runoff. Water quality measures were made at the one-foot depth level and at the bottom of the CTS24. The nitrate removal averaged 71% at the one-foot level and 89% at the two-foot depth. Total nitrogen was in the nitrate form.
A vegetated filter strip (VFS) with B&G™ CTS24 media was used to document the removal of nutrients in runoff water from a roadway (Shorkri, 2021). A test bed in Orlando at the University of Central Florida was used with 28 measurements for water volume and water quality. The results illustrate the need to have about 20 feet of runoff area adjacent to the roadway to achieve nitrification and denitrification. The average removal of TN and TP was calculated at 80(+/-)5% and 84(+/-) 9%, respectively. The percent concentration ratio of nitrogen species NOx:NH3:ON in the runoff was 10:25:65. The average influent TN and TP concentrations were 1.75 mg/L and 0.21 mg/L, respectively.
Expected Runoff Concentration:
Literature citing event mean concentrations (EMC) of each constituent in roadway runoff is shown in the following Table using the following references: Driscoll et al., 1990; Thomson et al., 1997; Kayhanian et al., 2007; Harper and Baker, 2007; Winston et al. 2012; Winston and Hunt, 2016, Kibler et al., 2020). Road runoff was used as it was more complete in the species definition of TN. The EMC is defined as the mass per unit runoff volume and in units of (µg/L). The mean and range of reported roadway runoff nutrient loads as event mean concentrations (EMC) are from Florida, Minnesota, California, and North Carolina.
References for EMCs
Driscoll, E.D., Shelley, P.E., Strecker, E.W., 1990. Pollutant loadings and impacts from highway stormwater runoff. Volume I: Design Procedure (No. FHWA-RD-88-006).
Harper, H.H., Baker, D.M., 2007. Evaluation of current stormwater design criteria within the state of Florida. Florida Department of Environmental Protection, p. 327.
Kayhanian, M., Suverkropp, C., Ruby, A., Tsay, K., 2007. Characterization and prediction of highway runoff constituent event mean concentration. Journal of Environmental Management. 85(2), 279-295. https://doi.org/10.1016/j.jenvman.2006.09.024
Kibler, K.M., Chang, N.B., Wanielista, M.P., Wen, D., Shokri, M., Valencia, A., Lustoso-Alves, E., Rice, N., 2020. Optimal Design of Stormwater Basins with Bio-Sorption Activated Media (BAM) in Karst Environments – Phase II: Field Testing of BMPs. FDOT Final Report BDV24-977-20.
Thomson, N.R., McBean, E.A., Snodgrass, W., Monstrenko, I.B., 1997. Highway stormwater runoff quality: Development of surrogate parameter relationships. Water, Air, and Soil Pollution, 94(3-4), 307-347. https://doi.org/10.1007/BF02406066
Winston, R.J., Hunt, W.F., 2016. Characterizing runoff from roads: Particle size distributions, nutrients, and gross solids. Journal of Environmental Engineering. 143(1), 04016074. https://doi.org/10.1061/(ASCE)EE.1943-7870.0001148
Winston, R.J., Hunt, W.F., Kennedy, S.G., Wright, J.D., Lauffer, M.S., 2012. Field evaluation of stormwater control measures for highway runoff treatment. Journal of Environmental Engineering. 138(1), 101-111. https://doi.org/10.1061/(ASCE)EE.1943-7870.0000454
Summaries of removal data and comparison to the credit used in the Florida ERP program
Notes: 1. The influent TN and TP concentrations were as expected in stormwater from roadways (TN range of about 0.68 to 3.2 mg/l, & TP range of about 0.07 to .56 mg/l) except for the highway 26 dual treatment of stormwater and groundwater and DeLand wastewater. 2. The water at DeLand is primarily nitrate and possibly more like wet pond detained water because of a lack of particulates. However, the TP concentrations at DeLand were much higher (average of 3.76 mg/L) and thus removal was not recorded above. 3. The treatment rate has to be slow enough to allow time for removal and in particular denitrification, as in these sites.
Infiltration (Treatment) Rate:
Infiltration or treatment rate is the primary design parameter for determining the effectiveness and area of the filter. Too much clay will limit the treatment rate to near zero or at a rate which is too expensive to build. From Patent # 10,696,567 June 30, 2020 (table 2), the material characteristics are shown. BAM is the CTS blend. Natural soil was used which had a 6.5% clay content.
With 6.5 % clay (Natural Soil), the infiltration (treatment) rate is the lowest at 4.25 inches per hour (0.003 cm/sec). A faster treatment rate that maintains removal would result in a smaller facility. IFGEM1, IFGEM2 and BAM (CTS) have faster rates. BAM (CTS) with 5% clay and 10% tire crumb has a treatment rate of 37 inches per hour (0.026 cm/sec). Conservatively, the BAM (CTS) mix is designed using a treatment rate of 10 inches per hour, which is supported by a field-derived infiltration rate after at least 10 years of operation of at least 10 inches per hour, provided there is no groundwater table interference.
The depth of filter specified by the permit agencies in Florida is a minimum of 24 inches. This depth is believed to minimize short circuiting or a reduction in average residency time. Since each filter reported in this review as well as used in many applications, is at least 24 inches in depth, the residence time based on the column packed with media is the media depth divided by the treatment rate. The residence time is 2.4 hours (24 inches divided by 10 inches/hour).
A factor of safety is usually required by practice and regulation. By practice, it is noted that the filtration rate decreases over time (sustainable porosity is one indication). That factor is usually 2 in the State of Florida. Thus, the residence time for a 24-inch depth media (CTS24) at the time of design using 5 inches/hour is 4.8 hours (24 inches divided by 5 inches/hour). Twelve- inch (12) filters are only permitted under special conditions. Those conditions should include a consideration of residence time.
Effectiveness must be reduced if the residence time is less than calculated using 5 inches/hour at the time of design.
Warranty:
The mix composition is under warranty as delivered to the installation site. This is done with a mixing facility that reports on the sampling for the source materials and mix specifications. The mix has no organic materials and thus is not expected to degrade over time.
TEXT REFERENCES:
Baldassari, T. (2007). “The Acute Toxicity Of Ground Recycled Automobile Tires On Aquatic Life With Model Species P. Promelas”. Thesis, UCF, 2007.
Wanielista, M., T. Baldassari, P. Ryan, B. Rivera, T. Shah, and E. Stuart. (2008). “Feasibility Study of Waste Tire Use in Pollution Control for Stormwater Management, Drainfields and Water Conservation in Florida”. Seminole County Florida and State DEP, Tallahassee Florida.
Hossain, Fahim, Ni-Bin Chang, and Marty Wanielista. (2009). “Modeling Kinetics and Isotherms of Functionalized Filter Media for Nutrient Removal from Stormwater”. Env Prog and Sus Energy, AIChE.
Wanielista, Marty, Ni-Bin Chang, Zhemin Xuan, Lisa Naujock, and Paul Biscardi. (2011). “Nitrogen Transport and Transformation Beneath Stormwater Retention Basins in Karst Areas and Effectiveness of Stormwater Best Management Practices for Reducing Nitrate Leaching to Ground Water Marion County, Florida”. FDEP Report # S0316 Florida Department of Environmental Protection, Marion County Board of County Commissioners, and Withlacoochee River Basin Board of the Southwest Florida Water Management District. October.
O’Reilly, A. M., et.al. (2011).”Identifying biogeochemical processes beneath stormwater infiltration ponds in support of a new best management practice for groundwater protection”, Proc. 7th International Groundwater Quality Conference held in Zurich, Switzerland, 13–18 June 2010. IAHS Pub. 342 in 2011.
O’Reilly, A. M., et.al., (2012). “Soil Property Control of Biogeochemical Processes beneath Two Subtropical Stormwater Infiltration Basins. Environ. Qual. 41:564–581 oi:10.2134/jeq2011.0204 Posted online 2 Feb.
Wanielista, Martin, Shane Williams, and Ni-Bin Chang. (2012). “Performance of a Bio-Retention System or How Come My Bio-Retention System Works?” Florida Stormwater Association Annual Meeting. June.
FDOT Final Report, BDK78 977-02, Rick Renna, Project Director. (2013). Research team of Wanielista, Martin; Hardin, Mike; Gogo-Abite, Ikiensinma; and Chopra, Manoj, “Stormwater Harvesting Using Retention and In-Line Pipes for Treatment Consistent with the new Statewide Stormwater Rule”. Tallahassee, Florida.
O’Reilly, A. M., N.-B. Chang, M. P. Wanielista, and Z. Xuan. (2014). “Groundwater Nutrient Reduction at Stormwater Infiltration Basins: Biogeochemical Assessment and Application of Biosorption Activated Media”. 30th Annual ASCE Water Resources Seminar, Orlando, Florida.
Williams, Shane and Wanielista, Martin. (2015). “Improving Nitrogen Treatment Efficiency in Dry Retention Ponds”, Florida Stormwater Association. June.
FDOT Final Report. BDV24-977-14, Rick Renna, Project Director. (2018). Research team of Ni-Bin Chang, et.al. “Comparative Nitrogen and Pesticide Removal with Sorption Media in Linear Ditch for Groundwater and Stormwater Treatment”. Tallahassee, Florida.
Chang, N-B. (2018). “Final Report Bio-sorption Activated Media for Nitrogen Removal in a Rapid Infiltration Basin – Monitoring Project”. Florida Department of Environmental Protection, Project No. NS 003. May.
Wanielista. Martin. (2018). “Dual Use Retention Basins”. Florida Stormwater Association Annual Meeting. June.
Valencia, A., Ordonez, D., Wen, D, McKenna. M., Chang, N-B, and Wanielista, MP. (2020). “The interaction of dissolved organic nitrogen removal and microbial abundance in iron-filings based green environmental media for stormwater treatment.” Environmental Research, 109815, 0013-9351/ Elsevier, June.
Shokri, Mohammad, et.al. (2021). “Hydraulic and nutrient removal performance of vegetated filter strips with engineered infiltration media for treatment of roadway runoff”. Journal of Environmental Management, Vol 300, 15. December.
- What were the test data and process for obtaining approval for ICS media?
Again, as noted with the CTS media, it is an extensive process. Reproduced is the wording used for use of the ICS media.
Process for obtaining State of Florida WMD and FDEP approval using as an example an ICS filter media with a mix of 91% sand, 5% iron filings and 4% clay. By Marty Wanielista, 2022
My understanding of guidelines for determining effectiveness of a Best Management Practice (BMP) for stormwater nutrient removal in the State of Florida follows. These are guidelines and not a rule and can require additional information related to design, maintenance and responsibility when a BMP is granted annual removal credit. - The acceptance of a proposed BMP with effectiveness must be the initiative of the responsible party (vendor, municipality, university, as examples). The initiative can include data from laboratory or from out-of-State field monitoring programs. In-State monitoring is preferred. Publications for performance data on removal effectiveness are considered to support the initiative.
- A WMD or FDEP must be in support and a permit issued for installation. The issuance of a permit assumes a monitoring program for validation of effectiveness. At least one site in the State must be monitored before acceptance of effectiveness. The effectiveness must be calculated on an average annual basis.
- The monitoring program must include at least 10 samples. Each sample must be weighted by the flow over each runoff event. The 10 samples must include at least one and no more than two from a rain event greater than 1 inch as well as least one sample each from the dry and wet seasons (June-October is considered the wet season).
- If part of or used with another BMP, (Aquatic plants in wet detention, filter media after wet detention, as examples), the overall effectiveness must be calculated considering the effectiveness of the other BMP.
- Removal effectiveness and service life must be defined. If different from initial proposal, the parameters are changed.
- After regulatory support (WMD or FDEP), it is permanently added as a BMP option for use in the State with design features and maintenance normal to its application.
For ICS filter media, the process to determine the proposed mix and effectiveness was: (note at the time of the research, the media was known as IFGEM)
Proposed BMP effectiveness was determined by laboratory studies which included a comparison to an existing media, namely BAM (B&G CTS) as well as the experience Dr. Wanielista had served on a national academy of science review committee for iron enhanced sand filters.
a. The Minnesota iron enhanced filters were review and clogging due to the use of iron filings were documented. By weight, 5-8% of iron filings (generally 3-5% by volume) are specified (Minnesota Stormwater Manual, stormwater.pca.state.mn.us design criteria). We recommend 5% by volume as the maximum iron filing in all IFGEM mixes.
b. For the clay %, we recommend 4%. Removal data to support the percent of clay is found in patent #10.787,373 (table 16). The clay is in media with 5% iron. From these data, up to 8% clay may be reasonable to use. But 6% and 8% clay in media has a low treatment rate.
c. We use data on removal from referred publications with the data from these publications in two patents, namely # 10,696,567 June 30, 2020 and #10,787,373 September 29, 2020. The claim of both patents is that nutrient removal is enhanced with the synergistic reaction of iron and clay. The media mixes, identified as BAM, IFGEM-1, IFGEM-2, and IFGEM-3 with the following components was used in a laboratory setting to determine removal effectiveness:
d. The TP and TN removal effectiveness for three different influent concentrations from patent # 10,787,373 (table 26) are:
e. Not considering the negative removal of BAM in the second influent condition above,
For BAM, average removal for TN is 62% and for TP is 37%
For IFGEM 1: 3.8% iron and no clay, average removal for TN is 58% and for TP is 42%
For IFGEM 2: 5% iron and clay @5%, average removal for TN is 90% and for TP is 78%
For IFGEM 3: 5% iron and clay @2%, average removal for TN is 91% and for TP is 73%
f. Conclusions related to effectiveness and components:
i. Iron and clay media enhanced sand removes more than a media with just iron enhanced sand (IFGEM 1 compared to both IFGEM 2 and IFGEM 3).
ii. Iron without clay removes about the same as BAM (BAM compared to IFGEM 1).
iii. The amount of clay over 2% (IFGEM 2 compared to IFGEM 3) does not appear to substantially effect the TN and TP removal.
g. Infiltration (treatment) rate is the primary design parameter. Too much iron oxide and clay will limit the treatment rate to near zero or at a rate which is too expensive to build. From Patent # 10,696,567 June 30, 2020 (table 2 ), the material characteristic are shown. Natural soil was used which had a 6.5% clay content.
With 6.5 % clay (natural soil), the infiltration (treatment) rate is the lowest at 4.25 inches per hour (0.003 cm/sec). A faster treatment rate that maintains removal would result in a smaller facility. IFGEM1, IFGEM2 and BAM have faster rates. BAM with 5% clay and 10% tire crumb has a treatment rate of 37 inches per hour (0.026 cm/sec). Tire crumb promotes a higher treatment rate because of larger size particles. IFGEM1 without tire crumb but with 3.8% iron treated at 40 inches per hour (0.028 cm/sec). IFGEM2 with tire crumb can treat at 24 inches per hour (0.017 cm/sec). Conservatively, the IFGEM mix of 91% sand, 5% sand, and 4% clay is designed using a treatment rate of 10 inches per hour.