Environmental Engineering Reference
In-Depth Information
obtained from mining (nonrenewable) or by evaporation of seawater that could be considered
renewable. Other ingredients are obtained through synthesis from fossil-based raw
materials. However, independent of whether these materials or ingredients come from
renewable or nonrenewable sources, they all have the common denominator that are
produced using nonrenewable energy. In a 100-percent sustainable food company all the
ingredients and materials would come from renewable sources and would be made using
renewable energy.
Water neutral
Food production is an water-intensive operation. Considerable amounts of water are used dur-
ing food processing, but agricultural operations to produce raw materials in the fields are even
more water intensive. Part of the water used for processing and agriculture comes from super-
ficial water (rivers, lakes, and in some cases, from desalinated seawater) and the rest from
aquifers. Aquifer depletion is a problem in many areas of the world where agricultural produc-
tion has benefited from the abundance of subterranean water for many years. Water from some
aquifers has been pumped at a rate higher than the rate or replenishment, which makes water
extraction nonsustainable in the long run.
A sustainable food company would use primarily surface water with minimal tapping of
subterranean water to allow aquifers to replenish. Water use would be optimized to avoid
unnecessary waste, thus creating a low water footprint for the company's products.
Net-zero air emissions
In the food production system, air emissions come from agricultural activities, transporta-
tion to the processing plants, processing, transportation to distribution centers, storage,
transportation to selling points, and storage at selling points. The system would not be
complete without the emissions generated by transportation of the food by the consumer and
its storage and preparation at home (see Chapter 9 for more on air emissions).
In this discussion, air emissions means anthropogenic emissions of the greenhouse gases
relevant to food production with the potential of a global climate effect. These are carbon
dioxide, methane, nitrous oxide, and hydrofluorocarbons (HFCs). Other environmental
pollutants, such as carbon monoxide, lead, nitrogen dioxide, ground-level ozone, particulate
matter, and sulfur dioxide that have a more local and regional effect, are regulated by laws
in many countries. Ozone-depleting substances including chlorofluorocarbons (CFCs),
hydrochlorofluorocarbons (HCFCs), halons, methyl bromide, carbon tetrachloride, and
methyl chloroform are in the process of being phased out after the signature of the Montreal
Protocol.
Air emissions come in different forms at each step of food production. Methane is produced
mainly during the agricultural phase through enteric fermentation, animal waste, rice
cultivation, and to a less extent, during crop residue burning. In the processing and consumption
phases, methane is produced during decomposition of solid and liquid wastes.
Carbon dioxide is produced at the agricultural phase, during processing, at all transportation
and storage phases, and preparation of food at home. Carbon dioxide is the main by-product
of burning any type of carbon-containing material and decomposition of carbon-rich materials
in the fields or as wastes.
In food production, the largest amount of nitrous oxide is released during fertilization of
soils, followed by animal solid wastes, and stationary combustion to produce power, electric-
ity, and transportation. Treatment of human sewage has important nitrous oxide emissions that
