10    BREWERY WASTEWATER TREATMENT BY CONTACT
OXIDATION PROCESS
Chang-Wu Huang, Associate Professor
Environmental Engineering Department
Wuhan Institute of Urban Construction
Wuhan, China
Yung-Tse Hung, Professor
Civil Engineering Department
Cleveland State University
Cleveland, Ohio 44115
INTRODUCTION
The brewery plants produce a large quantity of wastewaters, which contain high concentration of
organic pollutants, low concentration of nutrients, and have large variation in these parameters[lj.
Proper treatment of brewery wastewater is necessary in order to minimize the detrimental effect on
the environment. Since the wastewaters contain high concentration of biodegradable organics, the
most commonly used treatment method has been the biological treatment process[l,2].
Beers are beverages of low alcoholic content of 2-7%. The basic raw materials for manufacture of
beer are cereals of which barley is the most important material. Types of cereals used include barley,
flaked rice, corn, oats, and wheat, with rice and millet used in China. Hops are also added to produce
a more or less bitter taste and to control the subsequent fermentation process. Brewing sugars, syrups
such as corn sugar or glucose, and yeast are also added during beer making.
The flow diagrams for beer brewing are shown in Figures 1 and 2. The beer brewing is carried out in
two stages: 1) malting of barley and 2) brewing of beer from malt. In the malting process, barley is
removed from storage and placed in a tank and steeped with water to bleach out the color and allowed
to germinate while air and water are introduced to stimulate growth of enzymes. During the growth
period, oxygen is utilized and carbon dioxide is released while the enzyme diastase is produced.
Diastase is the biological catalyst that converts the dissolved starch to the disaccharide maltose and
then to monosaccharide glucose by the enzyme maltase. The monosaccharide glucose is then fermented to beer by yeast in stage 2. In stage 2, the brewing of beer, as shown in Figure 2, can be divided
into the following steps:
1. Mashing of coarse ground malt with water.
2. Converting insoluble starch into liquefied starch, and the soluble malt starch into dextrin and malt sugars in the pressure cookers.
3. Mixing the resulting boiling cooker mash with the rest of the malt in the malt tun, raising
the temperature to 168°C to prepare the brewer's wort, and cooled.
Water
I
Barley
Storage
Pre-soaking
&
Germination
Rinsing
Air Blower
Drying
Figure I.    Flow diagram for molting of barley.
90