Drinking water disinfection efficiency

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Question

What is the efficiency of drinking water disinfection methods, reported in log-clearance?

Answer

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library(OpasnetUtils)

objects.latest("Op_en7955", code_name = "variable")

Rationale

Data

References of efficiency of disinfection methods
Method	Campylobacter	E.coli O157:H7	Rotavirus	Norovirus	Cryptosporidium	Giardia
UV	^[1]	^[1]	^[1]	^[1]	^[1]	^[1]
Ozonization					^[2]	^[2]

FOR UV

Drinking water disinfection efficiency(mJ/cm^2)
Obs	Pathogen	1	2	3	4	5
1	campylobacter	3	7	10	14	NA
2	E.coli O157:H7	5	9	14	19	NA
3	rotavirus	10	20	29	39	NA
4	norovirus	NA	NA	NA	NA	NA
5	cryptosporidium	3	6	12	NA	NA
6	giardia	2	5	11	NA	NA

E.coli and Campulobacter jejuni corrected for environmental spp.
Cryptosporidium and giardia: no correction for environmental spp. (research needed).
Rotavirus SA-11
For noro: 0.8 log inactivation was estimated for a UV fluence of 20mJ/cm². At higher fluences (40 and 70mJ/cm^²) all samples were negative. However, it is uncertain to which degree inactivation assessed with RT-PCR is representative for inactivation assessed with infectivity assays.

The log decreases follow the formula

log₁₀(N_t/N) = -k * Fluence

where N_t is the microbial concentration after contact time t. Fluence is the product of the UV fluence rate (mW/cm²) and the exposure t (mWs/cm² = mJ/cm²).

OR

log₁₀(N_t/N) = -k * Fluence - b

where b is the y-intercept. This is used in cases where small amounts of UV don't have an effect, and the log linear decrease only begins at a certain level of UV. For some microbes there is also an upper limit to log decrease, after which adding fluence doesn't decrease the microbe concentration.

You have error(s) in your data:

Number of indices and result cells does not match

Drinking water disinfection efficiency(log-decrease)
Obs	TreatmentMethod	PathogenUnit
1	Ozonization	campylobacter	Logdecrease	0
2	Ozonization	E.coli O157:H7	Logdecrease	0
3	Ozonization	rotavirus	Logdecrease	0
4	Ozonization	norovirus	Logdecrease	0
5	Ozonization	cryptosporidium	Logdecrease	2
6	Ozonization	giardia	Logdecrease	2
7	None	campylobacter	Logdecrease	0
8	None	E.coli O157:H7	Logdecrease	0
9	None	rotavirus	Logdecrease	0
10	None	norovirus	Logdecrease	0
11	None	cryptosporidium	Logdecrease	0
12	None	giardia	Logdecrease	0

Calculations

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#This is code "Op_en7955/disinfectionall" on page [[Drinking water disinfection efficiency]]
library(OpasnetUtils)

DisinfectionAll <- Ovariable("DisinfectionAll", ddata = "Op_en7955", save = TRUE)

cat("Ovariable DisinfectionAll saved.\n")

Cut the data saved to the previous ovariable by chosen disinfection methods. The default choice includes UV and Ozonization. The creation of the ovariable with the choices can be found on page Drinking water treatment efficiency

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#This is code "Op_en7955/variable" on page [[Drinking water disinfection efficiency]]
library(OpasnetUtils)

Disinfection <- Ovariable("Disinfection",
                                 dependencies=data.frame(
                                   Name = c("DisinfectionAll", "Treatment"),
                                   Ident = c("Op_en7955/disinfectionall", "Op_en7954/treatmentchoice")
                                 ),
                                 formula = function(...){
                                   return(DisinfectionAll*Treatment)
                                 }
)

objects.store(Disinfection)
cat("Ovariable Disinfection saved. \n")

References

↑ ^1.0 ^1.1 ^1.2 ^1.3 ^1.4 ^1.5 Hijnen et al. 2006: Inactivation credit of UV radiation for viruses, bacteria and protozoan (oo)cyst in water: a review. Water Research 40(1) p3-22
↑ ^2.0 ^2.1 Haas CN, Kaymak B. 2003. Effect of initial microbial density on inactivation of Giardia muris by ozone.Water Res. 2003 Jul;37(12):2980-8.

[hijnen2006-1] 1.0 ^1.1 ^1.2 ^1.3 ^1.4 ^1.5 Hijnen et al. 2006: Inactivation credit of UV radiation for viruses, bacteria and protozoan (oo)cyst in water: a review. Water Research 40(1) p3-22

[haas2003-2] 2.0 ^2.1 Haas CN, Kaymak B. 2003. Effect of initial microbial density on inactivation of Giardia muris by ozone.Water Res. 2003 Jul;37(12):2980-8.

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Drinking water disinfection efficiency

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Data

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