Calculates TOC concentration after passing through GAC treatment according to the model developed in
"Modeling TOC Breakthrough in Granular Activated Carbon Adsorbers" by Zachman and Summers (2010), or the logistics curve approach in EPA WTP Model v. 2.0 Manual (2001).
For a single water use gac_toc; for a dataframe use gac_toc_df.
Use pluck_water to get values from the output water as new dataframe columns.
For most arguments in the _df helper
"use_col" default looks for a column of the same name in the dataframe. The argument can be specified directly in the
function instead or an unquoted column name can be provided.
Water must contain DOC or TOC value.
Usage
gac_toc(
water,
ebct = 10,
model = "Zachman",
media_size = "12x40",
bed_vol,
pretreat = "coag"
)
gac_toc_df(
df,
input_water = "defined",
output_water = "gaced",
model = "use_col",
pluck_cols = FALSE,
water_prefix = TRUE,
media_size = "use_col",
ebct = "use_col",
bed_vol = "use_col",
pretreat = "use_col"
)Source
See references list at: https://github.com/BrownandCaldwell-Public/tidywater/wiki/References
Zachman and Summers (2010)
U.S. EPA (2001)
Arguments
- water
Source water object of class "water" created by define_water
- ebct
Empty bed contact time (minutes). Model results are valid for 10 or 20 minutes. Defaults to 10 minutes.
- model
Specifies which GAC TOC removal model to apply. Options are Zachman and WTP. Defaults to Zachman.
- media_size
Size of GAC filter mesh. Model includes 12x40 and 8x30 mesh sizes. Defaults to 12x40.
- bed_vol
Bed volume of GAC filter to predict effluent TOC for.
- pretreat
Specifies the level of pretreatment prior to GAC treatment. Defaults to "coag". Other option is coagulant, ozonation, and biotreatment, called "o3biof".
- df
a data frame containing a water class column, which has already been computed using define_water_df. The df may include columns named for the media_size, ebct, and bed volume.
- input_water
name of the column of water class data to be used as the input for this function. Default is "defined".
- output_water
name of the output column storing updated parameters with the class, water. Default is "gaced".
- pluck_cols
Extract water slots modified by the function (doc, toc, uv254) into new numeric columns for easy access. Default to FALSE.
- water_prefix
Append the output_water name to the start of the plucked columns. Default is TRUE.
Value
gac_toc returns a water class object with updated DOC, TOC, and UV254 slots.
gac_toc_df returns a data frame containing a water class column with updated DOC, TOC, and UV254 slots
Details
GAC model for TOC removal
The function will calculate TOC concentration by GAC adsorption in drinking water treatment. UV254 concentrations are predicted based on a linear relationship with DOC from WTP Model Equation 5-93 and 5-94.
Examples
water <- define_water(ph = 8, toc = 2.5, uv254 = .05, doc = 1.5) %>%
gac_toc(media_size = "8x30", ebct = 20, model = "Zachman", bed_vol = 15000)
#> Warning: Missing value for alkalinity. Carbonate balance will not be calculated.
#> Warning: Major ions missing and neither TDS or conductivity entered. Ideal conditions will be assumed. Ionic strength will be set to NA and activity coefficients in future calculations will be set to 1.
# \donttest{
example_df <- water_df %>%
define_water_df() %>%
dplyr::mutate(
model = "WTP",
media_size = "8x30",
ebct = 10,
bed_vol = rep(c(12000, 15000, 18000), 4)
) %>%
gac_toc_df()
example_df <- water_df %>%
define_water_df("raw") %>%
dplyr::mutate(
model = "WTP",
bed_vol = 15000
) %>%
gac_toc_df(input_water = "raw")
# }