By-product
From Wikipedia, the free encyclopedia
A by-product is a secondary product derived from a manufacturing process or chemical reaction. It is not the primary product or service being produced. A by-product can be useful and marketable or it can be considered waste.
IEA offers the following definition for the purpose of life-cycle assessment:[1]
- ... main products, co-products (which involve similar revenues to the main product), by-products (which result in smaller revenues), and waste products (which provide little or no revenue).
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[edit] Major by-products
[edit] Animal sources
- blood meal – from slaughterhouse operations
- poultry by-product meal – clean parts of the carcass of slaughtered poultry, such as necks, feet, undeveloped eggs, and intestines
- chrome shavings – from a stage of leather manufacture
- collagen and gelatin – from the boiled skin and other parts of slaughtered livestock
- feathers – from poultry processing
- feather meal – from poultry processing
- fetal pigs
- lanolin – from the cleaning of wool
- manure – from animal husbandry
- meat and bone meal – from the rendering of animal bones and offal
- poultry litter – swept from the floors of chicken coops
- whey – from cheese manufacturing
[edit] Vegetation
- acidulated soap stock – from the refining of vegetable oil
- bagasse – the fibrous residue remaining after sugarcane or sorghum stalks are crushed to extract their juice
- black liquor from the production of cellulose pulp using the Kraft process
- bran and germ – from the milling of whole grains into refined grains
- brewer's yeast – from ethanol fermentation
- cereal food fines – from breakfast cereal processing
- corn steep liquor – from corn wet-milling
- distillers grains – from ethanol fermentation
- glycerol – from the production of biodiesel
- grape seed oil – recovered from leftovers of the winemaking process
- molasses – from sugar refining
- orange oil and other citrus oils – recovered from the peels of processed fruit
- pectin – recovered from the remains of processed fruit
- sawdust and bark – from the processing of logs into lumber
- soybean meal – from soybean processing
- stover – residual plant matter after harvesting of cereals
- straw – from grain harvesting
- tall oil from the production of cellulose pulp using the Kraft process
- vinasse – from the fermentation of sugar to ethanol fuel
[edit] Minerals and petro chemicals
- asphalt – from the refining of crude oil
- fly ash – from the combustion of bellend coal
- slag – from ore refining
- gypsum – from flue-gas desulfurization
- ash and smoke – from the combustion of fuel
- mineral oil – from refining crude oil to produce gasoline
- salt – from desalination
- Molybdenum – from copper extraction
[edit] Other
- sludge – from wastewater treatment
- waste heat - from electricity production and usage
