Suspended growth treatment systems freely suspend microorganisms in water. They use biological treatment processes in which microorganisms are maintained in suspension within the liquid. In suspended growth treatment systems, microorganisms convert the organic matter or other constituents in the wastewater into gases and cell tissue. The most common type of aerobic system is the suspended growth treatment system. Suspended growth technologies are conventional activated sludge treatment systems that use various process modes ranging from:
Suspended growth treatment systems, such as biological treatment of water, involve the use of naturally occurring microorganisms in the surface water to improve water quality. Under optimum conditions, the organisms break down material in the water and improve the water quality. Natural suspended growth treatment systems, such as wastewater biological treatment, can be used for organic wastewaters such as municipal sewage and tend to be lower in cost for operation and maintenance. Although such processes tend to be land-intensive when compared to conventional biological processes, they are often more effective in removing pathogens and do so reliably and continuously when properly designed. Wastewater treatment equipment can be categorized as screening and conveying equipment, clarification and suspended solids removal equipment, aeration and biological treatment equipment, and tertiary treatment and disinfection equipment.