Organic Waste Recycling

48 Organic waste recycling: technology and management

Table 2.15 Characteristics of brewery wastewater (Tantideeravit 1975)

BOD 5 (mg/L) 1800

COD (mg/L) 3100

Total solids (mg/L) 1750

Suspended solids (mg/L) 800

pH 7.5

Alkalinity (mg/L as CaCO 3 ) 160

Table 2.16 Characteristics of stockyard wastewater (U.S.PHS 1943)

Total suspended solids (mg/L) 170

Volatile suspended solids (mg/L) 13

Organic nitrogen (mg/L) 11

Ammonia nitrogen (mg/L) 8

BOD 5 (mg/L) 60

Slaughter: bleeding and carcass separation
Figure 2.8 is a schematic diagram of a slaughter house operation. After killing, the
carcasses are bled, the hide is stripped, the abdominal mass is removed and the
carcass is split into smaller pieces. At some stage washing takes place which gives
rise to dirt, dung, grit, etc., in the effluent.
Blood is normally kept separate to reduce the polluting load in the effluent
and because it can be a valuable by-product. The abdominal mass is removed and
sorted for collection by the pharmaceutical and by-products industries.
The paunch (stomach) is removed, and it is important to keep the contents
out of the normal effluent stream (to simplify subsequent treatment). The
contents, partly digested food, are handled separately; they are best kept as dry
as possible and disposed of on land as fertilizer.
The cutting down of the carcass involves blood, bone dust, tissue and fat
contaminating the wash water, some of which can be caught in traps, but this is
the main pollutant which has to be dealt with.

Meat processing (Griffiths 1981)
Meat processing plants are completely different from abattoirs. There is no
paunching, no blood, no gut; but there is a lot more meat and fat wastes plus all
sorts of additives, e.g. pastry, soya, sauces, spices, preservatives, colorings, etc.