Treatment of High Strength Fatty Acid
Derivative Wastewaters
THOMAS J. MULLIGAN, Vice President
RICHARD P. SHERIDAN, Project Manager
Hydroscience, Inc.
Westwood, New Jersey 07675
INTRODUCTION
Many industrial plants in the organic chemical and food industries produce
wastewaters that contain relatively high concentrations of fats, oils, and greases. Animal
fats, vegetable oils, fatty acids, and many derivatives obtained from these materials are
measured in the standard analytical procedures for fats, oils, and greases. The fats, oils,
and greases can be free-floating and hence, readily separable in conventional separation
type treatment units, or emulsified where treatment systems must be capable of breaking the
emulsion and/or removing the emulsified material. These investigations summarize the
development of a treatment system and the evaluation of the recommended full scale
biological system to remove relatively high concentrations of highly emulsified fats, oils,
and greases from the wastewaters of an organic chemical plant.
WASTE ORIGIN
The plant processes that generate wastewater use animal fats (tallow), vegetable, and
coconut oils as raw materials. In the manufacturing operation, these materials are
hydrolyzed and split into saturated and unsaturated fatty acids. Separation of these acids is
accomplished by distillation or solvent crystallization. A by-product of the splitting
operation, glycerol, is sold without further processing at the site.
The fatty acids are reacted with nitrogen compounds, alcohols, methyl chlorides, or
other materials to form the many intermediate and end products produced at the plant.
Some of the compounds include primary, secondary, tertiary, and quarternary ammonium
salts; amines, diamines, amides, esters, and nitriles. Many of these are water soluble, water
dispersible, and excellent emulsifying agents. When discharged to the process sewer, these
agents form emulsions with other process wastes.
Chemically, a fatty acid is a combination of a long non-polar hydrophobic hydrogen
carbon chain and a strong polar, hydrophillic carboxyl group. The non-polar hydrocarbon
chain is a linkage of carbon atoms which gives low water solubility to the molecule. Fatty
acids having less than ten carbon atoms are liquids which decrease rapidly in water
solubility with an increasing chain length. The acids from capric (C-10) on up are solids at
room temperature, and are relatively insoluble in water. Fatty acids are soluble in ether,
alcohol, and other organic solvents (i.e., hexane, trichloro-trifluro ethane, etc.).
997