Feedlot wastes are affected by many factors, including animal species; size and age, animal feed and water intake, microenvironment on the feedlot and climate. These properties are further modified after excretion by the waste handling system and biochemical activities.
Properties of feedlot wastes may be classified as physical, chemical and biological parameters. The most important physical parameters are quantity and solids content. The physical properties that are relevant are temperature, color, taste, odor, specific gravity, hydrophilic properties, with the most important being bulk density, particle size and viscosity.
Biochemical parameters with significance in feedlot wastewaters include biochemical oxygen demand (BOD), chemical oxygen demand (COD), total organic carbon (TOC) and soil oxygen demand (SOD). TOC is useful in monitoring efficiencies of treatment plants but is not used as a design parameter.
The important chemical parameters are pH, electrical conductivity, metals (toxic), fertilizer plant nutrients and other chemicals with biocidal properties. The fertilizer plant nutrients include nitrogen, phosphorus and potassium.
The final parameters are miscellaneous but still useful in feedlot waste management plans. These include population equivalent, animal equivalent and animal unit. With all the factors that go into feedlot waste management, it is impossible to arrive at a design value that would be suitable for all feedlot wastes. The numerical values given in this study are expected ranges and average values which may be used as guidelines in planning, not in detailed design.