Drinking water chlorination efficiency: Difference between revisions

Revision as of 12:37, 11 July 2019

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Question

How does chlorination affect the concentrations of pathogens in drinking water, reported in log-decrese?

Answer

Pathogen	Log-dercease
Campylobacter	8.837981871
E.coli O157:H7	7.182699561
Rotavirus	11.97117474
Norovirus	13.55252482
Cryptosporidium	0
Giardia	0.095329311

Rationale

Chloriantion efficiency, or chlorine's capacity to destroy microbes, depends on many factors: the form of the chlorine, temperature, retention period, pH and concentration as well as other chemicals in the water. In some circumstances it might efficiently kill all indicator organisms, but some active viruses, protists or their cysts may remain in the water. The meter to measure the efficiency of chlorination is kloorikokema ⇤--arg5411: . Someone else has to translate this --Heta (talk) 14:31, 4 July 2019 (UTC) (type: truth; paradigms: science: attack), which is the concentration multiplied by retention period, so called CT-value. The required CT-value depends on the temperature: the lower the temperature, the higher the CT-value has to be.

^[1]

Data

Pathogen sensitivity to chlorine:

The rows tell which pathogen the ct-values on that row are for.

The columns tell the ct-value required to decrease the amount of each pathogen in the drinking water to a certain level on the log-scale. Column 1 means pathogen concentration will drop to 10^-1 of the original, column 2 means the concentration will drop to 10^-2 and so on.

Drinking water chlorination efficiency: Difference between revisions((mg/l)*min)
Obs	Pathogen	1	2	3	4
1	Campylobacter	0.152	0.294	0.436	0
2	E.coli O157:H7	0.17	0.34	0.52	1.06
3	Rotavirus	0.12	0.16	0.2	0.3
4	Norovirus	0.09	0.18	0.245	0.314
5	Cryptosporidium	0	0	0	0
6	Giardia	75	150	216	0

Pathogen	Reference
Campylobacter	^[2]; ^[3]
E.coli O157:H7	^[4]; ^[5]
Rotavirus	^[6]
Norovirus	^[7]
Cryptosporidium	^[8]
Giardia	^[9]

Causality

Drinking water disinfection efficiency

Unit

logarithmic decrease

Calculations

CT-value = Chlorine residue concentration (mg/l)* time (min)

+ Show code - Hide code

  #This is code "Op_en7956/dose" on page [[Drinking water chlorination efficiency]]
  library(OpasnetUtils)

ChlorineDose = data.frame(ChlorineDoseResult = 1.5)

ChlorineDose = Ovariable("ChlorineDose", data = ChlorineDose, save = TRUE)

cat("Ovariable ChlorineDose saved.\n")

oprint(ChlorineDose)

+ Show code - Hide code

#This is code "Op_en7956/sensitivity" on page [[Drinking water chlorination efficiency]]
library(OpasnetUtils)

ClSensitivity <- Ovariable("ClSensitivity", ddata = "Op_en7956", save=TRUE)

cat("Ovariable ClSensitivity saved.\n")

oprint(ClSensitivity)

+ Show code - Hide code

# This is code "Op_en7956/CT" on page [[Drinking water chlorination efficiency]]
library(OpasnetUtils)
library(reshape2)

mrt <- 2 # mean residence time, the time water on average spends in each cstr
Ncstr <- 6 # the number of continuously stirred tank reactors
k <- 0.13 # the rate at which chlorine concentration decreases

CT <- Ovariable(
  "CT",
  dependencies =  data.frame(
    Name = c("ChlorineDose", "mrt", "Ncstr", "k"),
    Ident = c("Op_en7956/dose")),
  save=TRUE,
  formula = function(...){

# Produces a distribution of total time water spends in the contactor
# from an exponential probability distribution with lambda = 1/mrt
# 1000 iterations
Times <- data.frame(Iter= 1:openv$N, Result = 0)
for(i in 1:(Ncstr)) {
  Times$Result <- Times$Result + rexp(n=openv$N, rate= 1/mrt)
}

Times <- Ovariable(name="Times", output=Times)

# Integral of concentration along Times: 
# Int(ChlorineDose*exp(-k*Times)) = ChlorineDose*(-1/k)*exp(-k*Times)
# Definite integral from 0 to Times = ChlorineDose*(-1/k)*exp(-k*Times) - ChlorineDose(-1/k) = ChlorineDose/k (1-exp(-k*Times))

CT <- ChlorineDose/k * (1-exp(-k * Times))

return(CT)

}

)

cat("Ovariable CT saved.\n")

+ Show code - Hide code

# This is code "Op_en7956/efficiency" on page [[Drinking water chlorination efficiency]]
library(OpasnetUtils)
library(reshape2)

ChlorineEfficiency <- Ovariable("ChlorineEfficiency", save = TRUE, dependencies = data.frame(
  Name = c("CT", "ClSensitivity"),
  Ident = c("Op_en7956/CT", "Op_en7956/sensitivity")),
  formula = function(...){
  
  ClSensitivity <- EvalOutput(ClSensitivity)

  # make CT into an Ovariable, if it's not already
  if(!"ovariable" %in% class(CT)) CT <- Ovariable(name=CT, output=data.frame(Result=CT))
  CT <- EvalOutput(CT)
  sensname <- paste0(ClSensitivity@name,"Result") # put "ClSensitivityResult" into sensname
  ctname <- paste0(CT@name,"Result") # put "CTResult" into ctname
  
  ova <- merge(ClSensitivity, CT) # merge to get the variables into the same table
  ova$Logdecrease <- as.numeric(as.character(ova$Logdecrease)) # make sure Logdecrease-column is numeric
  
  out <- aggregate(
    1:nrow(ova@output), #take a set of row numbers included in ova...
    by = ova@output[ova@marginal & colnames(ova@output)!="Logdecrease"], #...that has a unique combination of values in the
            # index-columns, except Logdecrease. It takes the row numbers with different values of Logdecrease, with the
            # combination of other indices unique.
      FUN = function(x) {
      tmp <- ova@output[x,] # actually takes those rows whose numbers were selected above from ova
      ord <- order(tmp$Logdecrease) # saves the order of rows ordered based on Logdecrease, smallest first.
      if(sum(tmp[[sensname]], na.rm=TRUE)==0) return(0) # if all the ct:s in this set of rows are 0, return 0
      out <- approx( # Otherwise use approx to interpolate the log-decrease for the ct value(s) from earlier
        x=tmp[[sensname]][ord],
        y=tmp$Logdecrease[ord],
        xout=tmp[[ctname]][1],
        rule=1:2
      )$y
      return(out)
    }
  )
  colnames(out)[colnames(out)=="x"] <- "Result"
  return(out)

  }
)

cat("Ovariable ChlorineEfficiency saved.\n")

oprint(ChlorineEfficiency)

References

↑ Valve, M ja Isomäki, E. 2007. Klooraus - Tuttu ja turvallinen? Vesitalous 4/2007.
↑ Blaser, M. J., Smith, P. F., Wang, W.‐L. L. and Hoff, J. C. (1986). "Inactivation of Campylobacter jejuni by Chlorine and Monochloramine." Applied and Environmental Microbiology 51(2): 307‐311.
↑ Lund, V. (1996). "Evaluation of E. coli as an indicator for the presence of Campylobacter jejuni and Yersinia enterocolitica in chlorinated and untreated oligotrophic lake water." Water Research 30(6): 1528‐ 1534.
↑ Blaser, M. J., Smith, P. F., Wang, W.‐L. L. and Hoff, J. C. (1986). "Inactivation of Campylobacter jejuni by Chlorine and Monochloramine." Applied and Environmental Microbiology 51(2): 307‐311.
↑ Lund, V. (1996). "Evaluation of E. coli as an indicator for the presence of Campylobacter jejuni and Yersinia enterocolitica in chlorinated and untreated oligotrophic lake water." Water Research 30(6): 1528‐ 1534.
↑ Rice, E. W., Hoff, J. C. and III, F. W. S. (1982). "Inactivation of Giardia cysts by chlorine." Applied and Environmental Microbiology 43(1): 250‐251
↑ Keswick, B. H., Satterwhite, T. K., Johnson, P. C., DuPont, H. L., Secor, S. L., Bitsura, J. A., Gary, G. W. and Hoff, J. C. (1985). Inactivation of norwalk virus in drinking water by chlorine. Applied and Environmental Microbiology 50(2): 261-264.
↑ Benito Corona-Vasquez, Amy Samuelson, Jason L. Rennecker and Benito J. Mariñas (2002): Inactivation of Cryptosporidium parvum oocysts with ozone and free chlorine. Water Research 36, 4053-4063
↑ Rice, E. W., Hoff, J. C. and III, F. W. S. (1982). "Inactivation of Giardia cysts by chlorine." Applied and Environmental Microbiology 43(1): 250‐251

[1] Valve, M ja Isomäki, E. 2007. Klooraus - Tuttu ja turvallinen? Vesitalous 4/2007.

[2] Blaser, M. J., Smith, P. F., Wang, W.‐L. L. and Hoff, J. C. (1986). "Inactivation of Campylobacter jejuni by Chlorine and Monochloramine." Applied and Environmental Microbiology 51(2): 307‐311.

[3] Lund, V. (1996). "Evaluation of E. coli as an indicator for the presence of Campylobacter jejuni and Yersinia enterocolitica in chlorinated and untreated oligotrophic lake water." Water Research 30(6): 1528‐ 1534.

[4] Blaser, M. J., Smith, P. F., Wang, W.‐L. L. and Hoff, J. C. (1986). "Inactivation of Campylobacter jejuni by Chlorine and Monochloramine." Applied and Environmental Microbiology 51(2): 307‐311.

[5] Lund, V. (1996). "Evaluation of E. coli as an indicator for the presence of Campylobacter jejuni and Yersinia enterocolitica in chlorinated and untreated oligotrophic lake water." Water Research 30(6): 1528‐ 1534.

[6] Rice, E. W., Hoff, J. C. and III, F. W. S. (1982). "Inactivation of Giardia cysts by chlorine." Applied and Environmental Microbiology 43(1): 250‐251

[7] Keswick, B. H., Satterwhite, T. K., Johnson, P. C., DuPont, H. L., Secor, S. L., Bitsura, J. A., Gary, G. W. and Hoff, J. C. (1985). Inactivation of norwalk virus in drinking water by chlorine. Applied and Environmental Microbiology 50(2): 261-264.

[8] Benito Corona-Vasquez, Amy Samuelson, Jason L. Rennecker and Benito J. Mariñas (2002): Inactivation of Cryptosporidium parvum oocysts with ozone and free chlorine. Water Research 36, 4053-4063

[9] Rice, E. W., Hoff, J. C. and III, F. W. S. (1982). "Inactivation of Giardia cysts by chlorine." Applied and Environmental Microbiology 43(1): 250‐251

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Drinking water chlorination efficiency: Difference between revisions

Revision as of 12:37, 11 July 2019

Contents

Question

Answer

Rationale

Data

Causality

Unit

Calculations

See also

References

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