Reviewed by Zhiqiang Hu
Professor of Civil and Environmental Engineering

Nomenclature and conversion factors

• acre (ac) = 43,560 square feet
• acre-inch (ac. in.) = one inch depth over one acre (27,154 gallons)
• acre-foot (ac. ft.) = one foot depth over one acre (43,560 cubic feet)
• acre-foot of soil = 1,600 to 2,000 tons
• cubic foot (cu. ft.) = 7.48 gallons = 62.4 pounds of biosolids
• cubic yard (cu. yd.) = 27 cubic feet = 1,685 pounds of biosolids
• gallon (gal) = 8.34 pounds of biosolids
• hectare (ha) = 2.47 acres
• kilogram (kg) = 1,000 grams
• kilograms per hectare (kg/ha)
• milligram (mg) = 0.001 grams
• microgram (??g) = 0.000001 gram
• metric ton (mt) = 2,204.6 pounds
• milligrams per kilogram (mg/kg) = parts per million (ppm). A measurement by weight that can be expressed either as a wet weight or dry weight basis.
• micrograms per kilogram (??g/kg) = parts per billion (ppb)
• nanograms per kilogram (ng/kg) = parts per trillion (ppt)
• one pound = 454 grams
• ppm (dry weight) in soil x 2 = pounds per acre for six inch soil depth
• kg/ha x 0.8907 = pounds per acre
• pounds per dry ton x 0.04167 x percent total solids = pounds per 1,000 gal
• mg/kg dry weight x 0.002 = pounds per dry ton
• mg/kg dry weight x 0.0000833 x percent total solids = pounds per 1,000 gal
• mg/kg dry weight x percent total solids ÷ 100 = milligrams per kilogram wet weight
• mg/kg wet weight x 100 ÷ percent total solids = milligrams per kilogram dry weight
• dry tons x 24,000 ÷ percent total solids = gallons
• dry tons x 100 ÷ percent total solids = wet tons
• dry tons x 118.7 ÷ percent total solids = cubic yards