anaerobic treatment [23]. (1987) gives an overview of relative cost indices and ranking for various treatment systems. According to him, the selection of the treatment system has to be undertaken on the basis of economic costs, environmental considerations, and the technical complexity of the system. Both the initial investment and the operating costs of the system must be taken into consideration. However, environmental and technical aspects cannot be quantified. Therefore subjective rankings must be used. Table 6 indicates that aerobic ponds is the least desirable method of concentrated wastewater treatment in places were productive land is to be used for construction of the ponds. Anaerobic lagoons are the least expensive and are used more often than any other treatment in the management of wastewater from feedlots. However, they are not recommended as a permanent solution [17].
Table 6.
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a Exclusive of land acquisition costs. It is assumed that land used in the construction of the treatment plant is owned by the feedlot.
b Index is the ratio of the treatment cost to that of the least cost treatment. Thus, the least cost treatment would have an index of 1. An index of 6 means 6 times more expensive than the least cost treatment in that category.
c Ranking is a judgement ranking of the six potential systems ranked in order of preference from 1 to 6. The ranking is not on the basis of cost, nor does a ranking of 6 means it is 6 times less diserable than that ranked 1 in the same category.
d Index/rank is a combination of cost rations and judgement rankings reflecting the author s preference based on technical, economic, and ecological feasibility of the system [33].
Conclusions
The conclusion that needs to be drawn is clear. There is an urgent demand for proper, well described, reference values ​​on waste production. Monitoring programs need to be set up to allow for a more reliable environmental impact assessment of animal product processing than is presently the case.monitoring programs should result in emission factors per unit of product processed. Because of the diversity in processes and waste production, proper data collection on waste processing will be an expensive and time consuming undertaking. br/>
References
1) Augsburger, N.D., H.R. Bohanon, J.L. Calhoun and J.D. Hildinger (1980). Environmental control handbook for poultry and livestock. Acme Engineering & Manufacturing Corp., Muskogee, Oklahoma. p align="justify">) Barnes, D., Forster, C.F. and Hrudey, S.E. (1984). Sur...
