Page 131 - Sustainability in the Process Industry Integration and Optimization

108 Cha p te r F i v e

an overview of available information on the fruit and vegetable–
processing industry. Using BAT as guidance, the study proposes:

• To Flemish authorities: Permit conditions and techniques for
which investment support may be offered because they are
less detrimental to the environment
• To Flemish companies: Guidelines for implementing the
concept of BAT

As described in the study, the fruit and vegetable–processing
industry comprises the sectors of frozen fruits and vegetables, canned
fruits and vegetables, processed potatoes, peeled potatoes, and fruit
juices. The most important environmental problems are the use of
large volumes of ground water and the production of wastewater
polluted with organic carbon, nitrogen, and phosphorus. Information
on BAT candidates was obtained mostly from expertise present in
Belgium and neighboring countries. More than a hundred different
techniques were selected and examined in terms of technical and
economical feasibility. Best available techniques in wastewater
treatment incorporate, for example, primary and aerobic wastewater
treatment for small potato-peeling enterprises as well as primary,
anaerobic, and aerobic wastewater treatment for large-scale
processing sites. The BAT concept was the basis for concluding that
Flemish wastewater discharge limits on surface water were
technologically and economically feasible, although new limits
(25–50 mg/L) on total phosphorus discharge were suggested. Annual
wastewater treatment costs for an average enterprise were estimated
to be €2.5–3.5 million. For small potato-peeling companies,
wastewater discharge into the sewer system was found to be most
appropriate.
Water-saving measures and the reuse of water may reduce
groundwater consumption by as much as 25–30 percent. A good
source for BAT practices is ENVIROWISE—a U.K. government
program managed by Momenta (a division of AEA Technology Plc)
and TTI (a division of Serco Ltd.)—which offers practical
environmental advice for business. Their web site (ENVIROWISE,
2009) provides a wide range of information including news and best
practice examples.
5.2.3 Water Footprint
Hoekstra (2008) defined the water footprint (WFP) as an indicator of
direct and indirect water use, which is measured in terms of water
volumes consumed, evaporated, and/or polluted. The WFP includes
consumptive use of “virtual” green, blue, and gray water. The virtual
green water content of a product is the volume of rainwater that
evaporated during the production process. For the food industry,
this volume is consumed mainly by agricultural products and