Section Three
BIOLOGICAL SYSTEMS-B. ANAEROBIC
21    ANAEROBIC FILTER TREATMENT OF DAIRY
WASTEWATER
AT LOW TEMPERATURES
T. Viraraghavan, Professor
Faculty of Engineering
University of Regina
Regina, Saskatchewan
Canada S4S OA2
S. R. Kikkeri, Graduate Student
Department of Industrial Engineering
West Virginia University
Morgantown, West Virginia 26506
INTRODUCTION
Dairy wastes are generally dilutions of milk or milk products, together with detergents, sanitizers,
lubricants, chemicals from boiler and washings from tank trucks. The strength of the waste varies
very widely. In the United States and New Zealand, the chemical oxygen demand (COD) of the dairy
plant wastes is said to vary in the range of 80-95,000 mg/L and 180-23,000 mg/L respectively,1
although 4,000 mg/L is the typical strength.2 The mean COD of the effluent of a dairy plant in
Canada was reported to be 3390 mg/L.3 Only limited information is available on the performance of
the anaerobic filters in treating dairy wastewater at low temperatures. In this context, it was proposed
to study the performance of anaerobic filters treating dairy wastewater operating at 10-20°C and
compare this performance with anaerobic filters operating at 30-35°C.
The primary objective of the study was to evaluate the performance of anaerobic filters operating at
12.5°C, 21°C and 30°C, treating dairy wastewater, especially to determine the effect of low temperature under different hydraulic retention times (HRTs); the effect of temperature (21° vs 30°C) on
start-up of these anaerobic filters was to be investigated as part of the study. The performance of the
anaerobic filters under continuous operating conditions was to be assessed in respect of the efficiency
of removal of various parameters such as BOD, COD and suspended solids (SS); volatile acids (VA)
production and methane (CH4) production were also to be examined. Other objectives of this study
were: 1) to examine the effect of organic loading on treatment efficiency; and 2) to examine the effect
of HRT on treatment efficiency.
MATERIALS AND METHODS
Dairy Wastewater
The wastewater for the study was collected every week from a local dairy which produces milk and
cream. Before each sample was transferred to the feed barrels, it was analyzed for COD and pH and
were adjusted to approximately 4000 mg/L and 7.0, respectively.
Reactors
The reactors used for this study were constructed of clear acrylic material with an internal diameter
of 100 mm. Each reactor contained two equal sections 600 mm long for a total height of 1.2 m. Gas
which escaped from the top of the reactor was collected by a water displacement method. The empty
volume of each reactor was 9.48 L. The volume occupied by the media in each reactor was 0.33 L;
thus the effective volume of the reactor with media was 9.15 L.
44th Purdue Industrial Waste Conference Proceedings, © 1990 Lewis Publishers, Inc., Chelsea, Michigan 48118.
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