solvedose_ph: Calculate a desired chemical dose for a target pH

Description

Calculates the required amount of a chemical to dose based on a target pH and existing water quality. The function takes an object of class "water", and user-specified chemical and target pH and returns a numeric value for the required dose in mg/L. For a single water, use solvedose_ph; to apply the model to a dataframe, use solvedose_ph_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_ph(water, target_ph, chemical)
solvedose_ph_df(
  df,
  input_water = "defined",
  output_column = "dose",
  target_ph = "use_col",
  chemical = "use_col"
)

Value

solvedose_ph returns a numeric value for the required chemical dose.

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

Arguments

water: Source water of class "water" created by define_water
target_ph: The final pH 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".
output_column: name of the output column storing doses in mg/L. Default is "dose".

Details

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

Examples

Run this code

water <- define_water(ph = 7, temp = 25, alk = 10)

# Calculate required dose of lime to reach pH 8
solvedose_ph(water, target_ph = 8, chemical = "caoh2")


example_df <- water_df %>%
  define_water_df() %>%
  solvedose_ph_df(input_water = "defined", target_ph = 8.8, chemical = "naoh")