chemdose_dbp_chain function

Apply chemdose_dbp within a data frame and output a column of water class to be chained to other tidywater functions

DBP = disinfection byproduct

chemdose_dbp_chain(
  df,
  input_water = "defined_water",
  output_water = "disinfected_water",
  cl2 = 0,
  time = 0,
  treatment = "raw",
  cl_type = "chlorine",
  location = "plant"
)

Arguments

• df: a data frame containing a water class column, which has already been computed using define_water_chain. The df may include a column named for the applied chlorine dose (cl2), and a column for time.
• input_water: name of the column of water class data to be used as the input for this function. Default is "defined_water".
• output_water: name of the output column storing updated parameters with the class, water. Default is "disinfected_water".
• cl2: Applied chlorine dose (mg/L as Cl2). Model results are valid for doses between 1.51 and 33.55 mg/L.
• time: Reaction time (hours). Model results are valid for reaction times between 2 and 168 hours.
• treatment: Type of treatment applied to the water. Options include "raw" for no treatment (default), "coag" for water that has been coagulated or softened, and "gac" for water that has been treated by granular activated carbon (GAC). GAC treatment has also been used for estimating formation after membrane treatment with good results.
• cl_type: Type of chlorination applied, either "chlorine" (default) or "chloramine".
• location: Location for DBP formation, either in the "plant" (default), or in the distribution system, "ds".

Returns

A data frame containing a water class column with predicted DBP concentrations.

Details

This function allows chemdose_dbp to be added to a piped data frame. Its output is a water class, and can therefore be used with "downstream" tidywater functions. TTHM, HAA5, and individual DBP species will be updated based on the applied chlorine dose, the reaction time, treatment type, chlorine type, and DBP formation location.

The data input comes from a water class column, as initialized in define_water or balance_ions.

If the input data frame has a chlorine dose column (cl2) or time column (time), the function will use those columns. Note: The function can only take cl2 and time inputs as EITHER a column or from the function arguments, not both.

For large datasets, using fn_once or fn_chain may take many minutes to run. These types of functions use the furrr package for the option to use parallel processing and speed things up. To initialize parallel processing, use plan(multisession) or plan(multicore) (depending on your operating system) prior to your piped code with the fn_once or fn_chain functions. Note, parallel processing is best used when your code block takes more than a minute to run, shorter run times will not benefit from parallel processing.

Examples

library(purrr)
library(furrr)
library(tidyr)
library(dplyr)

example_df <- water_df %>%
  mutate(br = 50) %>%
  define_water_chain() %>%
  balance_ions_chain() %>%
  chemdose_dbp_chain(input_water = "balanced_water", cl2 = 4, time = 8)

example_df <- water_df %>%
  mutate(br = 50) %>%
  define_water_chain() %>%
  balance_ions_chain() %>%
  mutate(
    cl2 = seq(2, 24, 2),
    time = 30
  ) %>%
  chemdose_dbp_chain(input_water = "balanced_water")

example_df <- water_df %>%
  mutate(br = 80) %>%
  define_water_chain() %>%
  balance_ions_chain() %>%
  mutate(time = 8) %>%
  chemdose_dbp_chain(
    input_water = "balanced_water", cl = 6, treatment = "coag",
    location = "ds", cl_type = "chloramine"
  )

# Initialize parallel processing
plan(multisession, workers = 2) # Remove the workers argument to use all available compute
example_df <- water_df %>%
  mutate(br = 50) %>%
  define_water_chain() %>%
  balance_ions_chain() %>%
  chemdose_dbp_chain(input_water = "balanced_water", cl2 = 4, time = 8)

# Optional: explicitly close multisession processing
plan(sequential)

See Also

chemdose_dbp