Skip to contents

Calculate a desired chemical dose for a target alkalinity

Source: R/solvedose_ph_alk.R
solvedose_alk.Rd

This function calculates the required amount of a chemical to dose based on a target alkalinity and existing water quality. Returns numeric value for dose in mg/L. Uses uniroot on the chemdose_ph function. For a single water, use solvedose_alk; to apply the model to a dataframe, use solvedose_alk_df. For most arguments, 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.

Usage

solvedose_alk(water, target_alk, chemical)

solvedose_alk_df(
  df,
  input_water = "defined",
  output_column = "dose",
  target_alk = "use_col",
  chemical = "use_col"
)

Arguments

water

Source water of class "water" created by define_water

target_alk

The final alkalinity in mg/L as CaCO3 to be achieved after the specified chemical is added.

chemical

The chemical to be added. Current supported chemicals include: acids: "hcl", "h2so4", "h3po4", "co2", bases: "naoh", "na2co3", "nahco3", "caoh2", "mgoh2"

df

a data frame containing a water class column, which has already been computed using define_water_df. The df may include a column with names for each of the chemicals being dosed.

input_water

name of the column of water class data to be used as the input. Default is "defined_water".

output_column

name of the output column storing doses in mg/L. Default is "dose_required".

Value

solvedose_alk returns a numeric value for the required chemical dose.

solvedose_alk_df returns a data frame containing the original data frame and columns for target alkalinity, chemical dosed, and required chemical dose.

Details

solvedose_alk uses stats::uniroot() on chemdose_ph to match the required dose for the requested alkalinity target.

See also

solvedose_ph

Examples

dose_required <- define_water(ph = 7.9, temp = 22, alk = 100, 80, 50) %>%
  solvedose_alk(target_alk = 150, "naoh")
#> Warning: Missing value for magnesium. Value estimated from total hardness and calcium.
#> 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.

example_df <- water_df %>%
  define_water_df() %>%
  dplyr::mutate(finAlk = seq(100, 210, 10)) %>%
  solvedose_alk_df(chemical = "na2co3", target_alk = finAlk)
#> Warning: Target alkalinity cannot be reached with selected chemical. NA returned.
#> Warning: Target alkalinity cannot be reached with selected chemical. NA returned.