chemdose_chlordecay function

Calculate chlorine decay

calculates the decay of chlorine or chloramine based on the U.S. EPA's Water Treatment Plant Model (U.S. EPA, 2001).

Source

U.S. EPA (2001)

See references list at: https://github.com/BrownandCaldwell-Public/tidywater/wiki/References

chemdose_chlordecay(
  water,
  cl2_dose,
  time,
  treatment = "raw",
  cl_type = "chlorine"
)

Arguments

• water: Source water object of class "water" created by define_water
• cl2_dose: Applied chlorine or chloramine dose (mg/L as cl2). Model results are valid for doses between 0.995 and 41.7 mg/L for raw water, and for doses between 1.11 and 24.7 mg/L for coagulated water.
• time: Reaction time (hours). Chlorine decay model results are valid for reaction times between 0.25 and 120 hours.Chloramine decay model does not have specified boundary conditions.
• treatment: Type of treatment applied to the water. Options include "raw" for no treatment (default), "coag" for water that has been coagulated or softened.
• cl_type: Type of chlorination applied, either "chlorine" (default) or "chloramine".

Returns

An updated disinfectant residual in the free_chlorine or combined chlorine water slot in units of M. Use convert_units to convert to mg/L.

Details

Required arguments include an object of class "water" created by define_water, applied chlorine/chloramine dose, type, reaction time, and treatment applied (options include "raw" for no treatment, or "coag" for coagulated water). The function also requires additional water quality parameters defined in define_water including TOC and UV254. The output is a new "water" class with the calculated total chlorine value stored in the 'free_chlorine' or 'combined_chlorine' slot, depending on what type of chlorine is dosed. When modeling residual concentrations through a unit process, the U.S. EPA Water Treatment Plant Model applies a correction factor based on the influent and effluent residual concentrations (see U.S. EPA (2001) equation 5-118) that may need to be applied manually by the user based on the output.

Examples

example_cl2 <- suppressWarnings(define_water(8, 20, 66, toc = 4, uv254 = 0.2)) %>%
  chemdose_chlordecay(cl2_dose = 2, time = 8)