Development and Operation of a Low Cost
Anaerobic Plant for Meat Wastes
MAXWELL B. RANDS, Chief Chemist
D. E. COOPER, Research Chemist
Auckland Farmers' Freezing Cooperative Ltd.
Auckland, New Zealand
INTRODUCTION
In anticipation of legislation on water pollution control, the study of meat
waste treatment was commenced by Auckland Export Meat Packing Companies
about 1950 in cooperation with the Auckland Metropolitan Drainage Board which
assisted with laboratory and pilot plant studies (1).
About this time also, considerable interest was taken in the work of Buswell
(2), and that of Fullen and Associates (3), and Steffan (4) on the disposal of meat
wastes by anaerobic digestion.
The Moerewa treatment plant, which is the subject of this paper, handles the
effluent of the northernmost meat packing plant in New Zealand in a mild climate with a temperature range of 10 to 25 C.
The only water course available for receiving effluent is a small stream of
approximately 20 cfs dry weather flow.
Following encouraging pilot plant results it was decided to develop an anaerobic plant on the lines of those evolving overseas, but modified if necessary to suit
the local conditions.
The general layout of the present plant is shown in Figure 1.
STANDARDS OF PURIFICATION
The New Zealand Waters Pollution Act was passed in 1953 and was followed
in 1963 by the regulations and explanatory booklet (5), which specify the minimum set of conditions for receiving waters. By putting the emphasis on the quality of the receiving water, rather than by giving directions as to treatment, the
regulations provide for treatments of effluents according to their strength, the dilution factor and state of purity of the receiving waters.
NATURE OF RAW WASTES
Slaughtering Capacity
The Moerewa plant is a comparatively small works by New Zealand standards.
The slaughtering capacities for the various classes of animal are:
Cattle  720 Per Day
Lambs  7,000 Per Day
Sheep  6,000 Per Day
Bobby Calves  4,500 Per Day
Pigs  600 Per Day
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