Questions for POU disinfection

[yalinli2]

@lsrowles Working on updating the POU disinfection module (see pou_disinfection branch), listing the potential bugs to be confirmed, because your original codes aren't on GitHub, I have to use screenshots here:

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• [x] This has been fixed

  1. In AgNP_CWF, I think you are trying to set the lifetime so that if only one of turbidity>10 or hardness>60 is true, lifetime is 1.5; if both turbidity>10 AND hardness>60, lifetime is 0.5. However, the way it is written, you'll never make lifetime to be 0.5

>>> def test(turbidity, hardness):
>>>     print(f'turbidity is {turbidity}, hardness is {hardness}')
>>>     if turbidity <= 10 and hardness <= 60:
>>>         print('lifetime is 2')
>>>     elif turbidity > 10 or hardness > 60:
>>>         print('lifetime is 1.5')
>>>     elif turbidity > 10 and hardness > 60:
>>>         print('lifetime is 0.5')

>>> test(5, 5)
turbidity is 5, hardness is 5
lifetime is 2
>>> test(15, 5)
turbidity is 15, hardness is 5
lifetime is 1.5
>>> test(15, 65)
turbidity is 15, hardness is 65
lifetime is 1.5

Instead, you should do this:

>>> def test2(turbidity, hardness):
>>>     print(f'turbidity is {turbidity}, hardness is {hardness}')
>>>     if turbidity <= 10 and hardness <= 60:
>>>         print('lifetime is 2')
>>>     elif turbidity > 10 and hardness > 60:
>>>         print('lifetime is 0.5')
>>>     else: print('lifetime is 1.5')

>>> test2(5, 5)
turbidity is 5, hardness is 5
lifetime is 2
>>> test2(15, 5)
turbidity is 15, hardness is 5
lifetime is 1.5
>>> test2(15, 65)
turbidity is 15, hardness is 65
lifetime is 0.5

[yalinli2]

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• [x] This has been fixed

  2. Related to POUChlorination on NaClO dose, the way it's written, NaClO dose will keep doubling. Will explain more in a meeting

[yalinli2]

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• [x] This has been fixed

  3. Same for POU_UV on lamp_life_span and UV_LED on LED_life_span, need to look at how the power utility is used

[lsrowles]

@yalinli2 I agree with your edit for pou_disinfection. Good catch on that.

I will follow up with you on the other two points.

[yalinli2]

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• [x] This has been fixed, should be 5.0231 kg CO2-eq per kg of stainless steel and 0.69712 kg CO2-eq per kWh of electricity.

  4. Is the CF of stainless steel and electricity from ecoinvent 3.9 (as others) or from Trimmer et al. (3.2 I think?)

[yalinli2]

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• [x] This has been fixed. Now assuming a normal distribution with mu=4 and sigma=1.4 based on global household size distribution

  5. Might need to update the sigma value in uncertainty analysis for household size

More explanation I'm referring to the household size distribution in the bwaise module,

    # Household size
    b = bw.household_size
    # 1.8/((844/4%)^0.5) is for standard error of a mean,
    # standard deviation divided by the square root of the population size,
    # 844 and 4% from Trimmer et al., changed from the distribution used in Trimmer et al.
    D = shape.Trunc(shape.Normal(mu=b, sigma=0.012), lower=1)
    @param(name='Household size', element=Toilet, kind='coupled', units='cap/household',
           baseline=b, distribution=D)
    def set_household_size(i):
        bw.household_size = i

The sigma value was reduced because how we used the household_size. We used it in the sense of an "average household size" to calculate how many toilets would be needed for a community:

number of toilets = total community population/household size/number of households served by one toilet

So the sigma should be adjusted.

Also note that the average household size does not have true uncertainty, i.e., if we survey the entire community, we can reduce the uncertainty to 0 because we'd know the how many households there are and calculate the average household size.

But for an individual household, true uncertainty exists - i.e., even if we survey the entire community, if we pick one household from the community, we still are not sure of its household size. If we don't use the household size in an average sense, e.g., assume we assign one toilet for one household (rather than calculating it from the total population), we should use the individual household distribution with the larger sigma value (i.e., 1.8).

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• [x] Bright has looked at the magnitude and p value for Spearman results.

  6. Has p-value from Spearman been considered?

[yalinli2]

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• [x] This has been fixed. Intended to be per kg based on how the value was calculated, I added a note

  7. In the impact item datasheet, is the functional unit of UVlamp/LED per kg or each?

[yalinli2]

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• [x] Yes, supposed to be 0, cost of the bottle is included in NaClO stream's price (bottle plus the chemical)

  8. Price for Polyethylene is 0?

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• [x] This has been fixed. The impact of PE of the bottle should be separated from the container to differentiate construction vs. operating impacts, I made changes in the script

  For POU chlorination, polyethylene in the container and for the Cl bottle should be counted together (otherwise they'll have different distributions in uncertainty analysis)

[yalinli2]

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• [x] Bright has double-checked the values in the script, has done a manual calculation and made sure results match.

  9. AgNP_lifetime is set to 3 in the datasheet, but is defined otherwise in the script, which one is correct? Legacy parameters shouldn't be in the datasheet (will affect uncertainty/sensitivity analyses, drag down simulation time, cause confusion)

[yalinli2]

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• [x] I updated uncertainty.py and added notes in the scripts

  10. No need to analyze for different population size (since it won't affect the results at all)

[yalinli2]

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• [x] This has been fixed, but should do a manual check with baseline values

  11. Incorrect UV run time & electricity calculation @lsrowles see what I changed in 1a4fe98 (totally found it out by coincidence), but F_vol is in m3 so the previous calculation was off by 1000, but the impacts on results were <1%

[yalinli2]

All tasks done, closing this issue!