From Exhaust Air Cleaning
Biological Exhaust Air Cleaning Structured Packings for Biological Processes. With the biological elimination of odors, a better efficiency can be achieved with less effort and less use of chemical agents than in a purely chemical-oxidative process. An increasing number of biological processes are being used nowadays. For example, in order to eliminate highly contaminated, very water-soluble and biologically degradable substances using bioscrubbers. Or by using biotrickling filters in order to remove odors that, by other methods, e.g. classical biofilters, adsorption plants or chemical scrubbers, can be only dissolved with great difficulty, are space-intensive and/or are contingent on high operating costs.
The biotrickling filter usually consists of the combination of an air humidifier and one or more downstream fixed bed reactors. The exhaust air flow to be cleaned is nearly saturated with water in the humidifier phase. At the same time, very water-soluble substances, such as ammonia, and any dusts are dissolved. The preconditioned exhaust air flow enters then into the fixed bed reactor, the actual biotrickling filter.
This biotrickling filter consists of a fixed bed made of structured plastic packings, which serve as a growth area for the bacteria.The preconditioned exhaust air flow enters into the biotrickling filter and flows through the column in intensive contact with the bacterial growth. The absorption fluid, which is fed in from above onto the packing, is used for the further humidification as well as for the feeding of nutrients, which are added to the system in the form of NKP fertilizers. Using the pH value measurement and control, optimal conditions are created for biofilm formation.
The composition of the biofilm adapts to the fed-in supply of nutrients. In the process, a large part of the metabolized components are exhaled as carbon dioxide. A small part is converted into more biomass and settles on the packing or is driven as a thin suspension in the cycle.
From time to time, a part of the surplus biomass must be discharged from the system. To do so, the packing is flushed at scheduled intervals or when needed and thus is relieved of surplus biomass.
The planning of an optimized biotrickling filter requires an ideal selection and design of the packing to be used as well as the sprinkler system. Type, structure and material properties as well as bed height and diameter of the biotrickling filter must be optimally coordinated to one another. Our specialists will be glad to assist you or offer a complete engineering and design package.