Industrial Ecology and the Geoenvironment - Sustainable Practices in Geoenvironmental Engineering - page 126

for typical pulp and paper processes. Debarking and chipping are the major operations
in the wood preparation process. Recovery of the removed bark for subsequent use as fuel
has reduced the waste discharge while decreasing energy costs. The pulping and bleach-
ing processes contribute the more signiicant impacts to the geoenvironment. The various
means for pulping range from mechanical, thermomechanical, and chemical. The most
frequently used process is the Kraft process, i.e., the sulfate process. This chemical process
(sulfate process) is not to be confused with the sulite pulping process, which is becoming
less popular as a process because the source wood species (spruce, balsam, ir, and west-
ern hemlock) are not as plentiful as the other species used for the kraft process. This kraft
process generates sludges high in chromium (Cr), lead (Pb), and sodium (Na).
The various processes shown in Figure 4.9 require considerable amounts of energy input
and extensive use of freshwater. Recycled water, identiied as whitewater, is used to augment
the water input to the coarse screening, bleaching, and wood preparation processes. For the
ine screening—washing and paper machine processes, freshwater is required. Other inputs
into the different processes include acid sulite liquor, alkaline sulfate liquor and neutral
liquor, chlorine-type bleaching chemicals such as hydrogen peroxide, ozone, peracetic acid,
sodium hypochloride, chlorine dioxide, and illers, dyes, alum, starch, and paper-coating
chemicals. The wastewater discharges from the many processes include pulping liquor, mill
washings and acid plant wastes, solvents and chlorine-based organic bleach compounds,
and general wastewaters. The organochlorines discharged in the wastewater and solid
wastes present some dificult toxic issues to the biotic receptors in the immediate geoenvi-
ronment. Discharged mill wastewaterer in the rivers causes considerable breeding problems
to several types of aquatic species. Solid wastes discharged include sludges from secondary
treatment plants containing inks, dyes, pigment, boiler ash, chemical processing, and waste
iber wastes including organochlorines (if chlorine has been used in the bleaching process).
4.5.3 Palm Oil Industries
Although palm oil industries may be considered as belonging in the larger group of vegetable
and oilseeds processing industries, its variety of transformed products have greater appli-
cation. The grouping of vegetable and oilseeds include palm, soybean, rapeseed (canola),
sunlower, and cottonseed. As agroprocessing industries, palm oil industries it into both the
food- and nonfood-producing agroindustries—with application in food industries as pro-
duction of nonhydrogenated and reined oils, shortening and margarine, and broad applica-
tion in nonfood industries such as chemical, cosmetic (personal care), and pharmaceutical.
Food industries are grouped into two kinds: (1) production of nonhydrogenated and reined
oils and solid fat products (e.g., margarine, shortening, nondairy ice cream, specialty fats,
chocolate) for human consumption and (2) production of animal feed (palm kernel cake and
palm kernel meal) from the by products. Nonfood industries are wide ranging, from indus-
tries devoted to production of (a) personal care products (cosmetics) such as creams, soaps,
and moisturizers, to (b) chemical products using epoxidized palm to produce polyurethanes
and polyacrylates and palm methyl esters, glycerol, and fatty acids as source materials to
produce a variety of products ranging from a diesel substitute to plasticizers. Harvesting of
the palm fruit bunches and milling belong to the upstream industry category. The output
from the mill is sent to the downstream reining plant and further on to the manufacturing
or production plants (e.g., chemical, cosmetic, pharmaceutical).
The two different kinds of oils or fats extracted from the palm fruit come from two sepa-
rate sources: (1) palm oil from the outer portion of the fruit and (2) palm kernel oil from
the kernel. Reinement of crude palm oil to reined oil is required to remove the moisture