Primary sedimentation Removes both settleable and floatable solids. Tendency for particles to aggregate, sometimes aided by the addition of chemicals. Secondary treatment Designed to remove BOD, usually by taking advantage of the same kind of biological processes that would other wise consume oxygen in water receiving the wastewater. Microorganisms provided with added oxygen are allowed to degrade organic material in solution or in suspension until the BOD of the waste has been reduced to acceptable levels. Trickling filter One of the simplest biological waste treatment processes.
Wastewater is sprayed over rocks or other solid support material covered with microorganisms.
The structure of the trickling filter is such that contact of the wastewater with air is allowed and degradation of organic matter occurs by the action of the microorganisms. Probably the most versatile and effective of all waste treatment processes. 2 Inversions Conditions characterized by high atmospheric stability. They limit the vertical circulation of air, resulting in air stagnation and the trapping of air pollutants in localized areas. Microclimates Highly localized climatic conditions.