One mg/l is for all intents and purposes equal to how many ppm?

One milligram per liter (mg/l) is indeed equivalent to one part per million (ppm) in water. This relationship holds true because both measurements indicate the concentration of a substance in a solution, and in the case of water, the density is very close to 1 gram per milliliter.

When you have 1 mg of a substance in 1 liter of water, you can express that as 1 ppm, which represents the ratio of the mass of the substance to the mass of the solution. Hence, the conversion from mg/l to ppm is straightforward and does not require any additional calculations when dealing with water.

Understanding this equivalence is crucial in wastewater management, as it allows operators to easily convert concentrations and interpret water quality data effectively.