Environmental Engineering Reference
In-Depth Information
ADVANCED UNITS OF MEASUREMENT AND CONVERSIONS
When readers reach this point in the presentation and move into the material that
follows, they may scratch their heads in wonder and ask: “Didn't we just cover this
material in the earlier part of this chapter?”
The answer? Well, sort of. We did cover many of the items presented below but the
reader should recall the basic thematic statement posted at the beginning of Chapter 1:
The key to learning math can be summed up in one word: Repetition! Repetition!
Repetition!
Thus, the following sections are partly based on providing the underlying struc-
ture, base, and foundation on which mathematical measurement and conversions are
made (i.e., repetition), while the rest of the chapter covers additional areas that are
becoming increasingly important to water or wastewater operators worldwide. Air
pollution parameters and unit conversions are one example. Incinerating biosolids
and eventual ash disposal can contribute to air pollution problems, along with soil
contamination via ash disposal. In addition, greenhouse gas conversions units are
covered in this chapter because biosolids are being applied as liquids and compost
to soils as a viable amendment. This is especially the case in the Pacific Northwest
where glaciated soils have resulted in nutrient-poor soils. The addition of treated
biosolids to nutrient-poor forest areas has shown significant improvement in the
growth rates of various timber types. Moreover, organic matter in biosolids improves
soil structure, which reduces runoff and erosion. Soil organisms also benefit from
nutrients in biosolids and the healthy soils it creates. Biosolids provide healthy, lush
growth in the understory of forests which, in turn, provides more food and hiding
cover for animals. We also address carbon footprint parameters and units and con-
versions associated with vehicle use at plants and other activities such as barbecuing
during plant picnics and other plant social gatherings.
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The units most commonly used by environmental engineering professionals are based
on the complicated English system of weights and measures; however, bench work is
usually based on the metric system, or International System of Units (SI), due to the
convenient relationship between milliliters (mL), cubic centimeters (cm
3
), and grams
(g). The SI is a modernized version of the metric system established by international
agreement. The metric system of measurement was developed during the French
Revolution and was first promoted in the United States in 1866. In 1902, proposed
congressional legislation requiring the U.S. government to use the metric system exclu-
sively was defeated by a single vote. Although we use both systems in this text, the SI
provides a logical and interconnected framework for all measurements in engineering,
science, industry, and commerce. The metric system is much simpler to use than the
existing English system, because all of its units of measurement are divisible by 10.
Before listing the various conversion factors commonly used in environmental
engineering it is important to describe the prefixes commonly used in the SI system.
These prefixes are based on the power 10. For example, a “kilo” means 1000 grams,
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