Wastewater contains a lot of toxic elements.
But for most types of these wastewater toxic elements, there will be a level of concentration below which they are rendered ineffective.
That is they become so diluted that they cannot cause any harmful effects in humans.
In this article I show how to determine this level.
It is necessary to know the minimum level of toxicity or the most diluted dosage that does not affect humans in any harmful way, even if it is taken in daily.
This level is technically known as the Tolerable Daily Intake (TDI).
The following formula is used to find out this level: NOAEL or LOAEL - = TDI UF where, NOAEL is the No-Observed-Adverse-Effect level, (the level where the toxin is rendered ineffective) LOAEL is the Lowest-Observed-Adverse-Effect level, (most diluted concentration level just above NOAEL where the toxin starts affecting adversely), and UF is the Uncertainty Factor.
The value obtained by this equation is used to derive another value, the Guideline Value for wastewater toxic elements.
This value is important to wastewater professionals as it is this value which determines the concentration of the wastewater toxic element, either in chemical or biological form, that does not pose any risk in any form to the human who consumes it during his lifetime.
It is calculated as TDI * BW * P -- = GV C where, BW is the Body Weight of the individual (assumed to be up to 5 kgs for the infants, 10 kgs for children and up to 60 kgs for the adults) P is the fraction of the value of the TDI that is associated with drinking water.
C is the amount of water consumed daily (assumed to be 0.
75 L for the infants, 1 L for children and 2 Ls for the adults).