Alkaline hydrolysis is an effective method for carcass disposal that involves using specific temperature and time parameters with potassium hydroxide (KOH) or sodium hydroxide. The USDA has used this process to decontaminate infected animal carcasses and materials by liquefying the organic material at high temperatures and retaining it for over an hour. This results in a nutrient-rich liquid effluent that can be disposed of through various methods like land application, dehydration, or sewers. The document discusses the applicability of this process and compares sodium and potassium hydroxide.

1. Alkaline Hydrolysis as an Effective Method for
Carcass Disposal
Keith L. Davidson, Jr, Raymond Otero, Jarod Gunderson, Arthur J. Davis, Ronald L.
Morgan, Mark Eimers, P. Frank Ross
U. S. Department of Agriculture (USDA), Animal and Plant Health Inspection Service
(APHIS), National Veterinary Services Laboratories (NVSL), Ames, Iowa
Phone: 515-663-7095
E-mail: keith.l.davidson@aphis.usda.gov
Key Points:
- applicability and operational standards of process
- safety concerns
- sodium vs. potassium hydroxide
- effluent disposal
- non-aqueous solutions
- plastics
- animal bedding decontamination
- cost value vs. incineration
- maintenance considerations
The USDA, APHIS, NVSL has used alkaline hydrolysis to decontaminate and dispose of
infected animal carcasses, tissue samples, aqueous liquids, inert surfaces that are
hydroxide compatible, and other materials. This process involves specific process
parameters of temperature and retention times. For transmissible spongiform
encephalopathies, the process is conducted at 150 C in a 1 normal potassium hydroxide
(1N KOH) for greater than 6 hours. Carcasses contaminated with viral and bacterial
agents have been treated at 121 C in a 1 N KOH for 1 hour or greater. Following the
retention time, the resulting effluent is cooled and the pH is lowered to between 9-10
prior to disposal. The 1 N KOH is essential for alkaline hydrolysis to ensure the
liquefaction of the organic material therefore ensuring a uniform heat application to all
parts of the material being processed. The resulting effluent consists of a nutrient rich
liquid and bone residue. The authors will discuss disposal of the effluent by means of
land application, dehydration, sanitary sewer, and/or incineration; issues surrounding
sodium versus potassium hydroxide; and some unique decontamination methods for
nonaqueous solutions, plastics, animal bedding, and other noncarcass materials.