The basic principal of the moving bed process is the growth of the biomass on plastic supports that move in the biological reactor via agitation generated by aeration systems(aerobic reactors) or by mechanical systems (in anoxic or anaerobic reactors). The supports are made from plastic with a density close to 1 g/cm3 letting them move easily in the reactor even when the capacity reaches 70%.
The moving bed processes come from the current trend in wastewater treatment, from the use of systems that offer an increased specific surface in the reactor for the growth of the biomass, achieving significant reductions in the biological reactor volume.
Initially fixed bed systems were used, however it was discovered that this type of process show a series of operational inconveniences such as the blocking of the bed because of the excessive growth of the biomass, this makes periodical cleaning obligatory. These drawbacks have caused the need for the creation of simple biofilm processes that eliminate them and that ease their operation; these are the moving bed processes.
This type of process can be applied both to treatment plants for the biodegradation of organic material as well as for installations with nutrient elimination, in urban and industrial wastewaters. Another application is the use of this technology in the redesign of current activated sludge processes, which only treat organic material, to expand them and include simple nitrogen elimination without the need to construct new biological reactors.
With respect to the aeration system is via a grid of perforated stainless steel tubes that avoid problems of efficiency loss, diffuser replacement, etc.