**1. Introduction**

312 Food Industrial Processes – Methods and Equipment

Singleton, V.L.; Rossi, J.A. (1965). Colorimetry of total phenolics with phosphomolybdic-

Swain, T.; Hillis, W.E. (1959). The phenolic constituents of *Punnus domestica*. I. Quantitative

Vaillant, F.; Millan, A.; Dornier, M.; Decloux, M.; Reynes, M. (2001). Strategy for economical

Vargas, P.N., Hoelzel, S.C., & Rosa, C.S. (2008). Determination of total polyphenols content

Yasan, H.; Zhijuan, J.; Shunxin, L. (2007). Effective clarification of apple juice using

Ziena, H.M.S. (2000). Quality attributes of Bearss Seedless lime (*Citrus latifolia* Tanaka) juice

microfiltration. *Journal of Food Engineering*, v. 48, p. 83-90.

*and Purification Technology*, v. 57, p. 366-373.

during storage. *Food Chemistry*, v.71, p.167-172.

158.

306

p. 63-68.

p. 11-15.

phosphotungstic acid reagents. *American Journal of Enology and Viticulture*, p. 144-

analysis of phenolic constituents. *Journal of the Science of Food and Agriculture*, v. 10,

optimisation of the clarification of pulpy fruit juices using cross flow

and antioxidant activity in commercial grape juices. *Alimentos e Nutrição,* v. 19, n. 1,

membrane filtration without enzyme and pasteurization pretreatment. *Separation* 

The food industry uses large amounts of water for many different purposes including cooling and cleaning, as a raw material, as sanitary water for food processing, for transportation, cooking and dissolving, as auxiliary water etc. In principle, the water used in the food industry may be used as process and cooling water or boiler feed water (EC, 2006). In 2008, for example, the total industrial water consumption in Finland was 7600 million m3 of which 34.5 million m3 was used by the food processing industry (Finnish Food and Drink Industries` Federation, 2010).

As a consequence of diverse consumption, the amount and composition of food industry wastewaters varies considerably. Characteristics of the effluent consist of large amounts of suspended solids, nitrogen in several chemical forms, fats and oils, phosphorus, chlorides and organic matter (Finnish Food and Drink Industries` Federation, 2005). Generally, the BOD (biochemical oxygen demand) and COD (chemical oxygen demand) of food industry wastewater is 10 or even 100 times higher than those of domestic wastewater (EC, 2006). Unpleasant odours are also a typical problem in food industry wastewaters. These odours are usually the result of gases (hydrogen sulphide, indole) produced by the anaerobic decomposition of organic matter (Metcalf & Eddy, 2003).
