Biocarriers are suspended in the wastewater of the reactor and are in continuous movement within a tank or reactor of specified volume. Biofilm, growing within the internal structures of the biocarriers, degrades dissolved pollutants in the wastewater stream. The pollutants that need to be removed to treat the wastewater are food, dissolved sugars or other various substrates, which contribute to the growth of the biofilm.
An aeration grid located at the bottom of the reactor supplies oxygen to the biofilm along with the mixing energy required to keep the biocarriers suspended and in constant movement within the reactor. Treated water flows from reactor into a grid or a sieve, the purpose of which is to retain the biocarriers within the reactor.
“Microorganisms in a biofilm wastewater treatment process are more resilient to process disturbances compared to other types of biological treatment processes,” CWT claims. “Thus, biofilm wastewater treatment technologies can be considerably more robust than other technologies.”
BioWish is the name of both the technology and the company supplying a novel wastewater treatment process. It combines a broad spectrum of microbial enzymatic activities with a complement of non-enzymatic, biocatalysts/cofactors, which work together to enhance overall digestive reaction rates. The result reduces odor, volatile organic compounds (VOC), BOD, COD and overall solid waste.
BioWish can reduce sludge production and handling by up to 60 percent due to accelerated digestion of organic waste. Its long list of claims includes: lower aeration requirements (30-50 percent less) for energy savings, increased biological efficiency in nutrient removal, lessened need for chemical additives, reduced odorous emissions and other volatile organic compounds, rapid removal of fats, oils and greases, plus suspended solids, nitrogenous waste and a wide range of contaminants; and overall efficiency improvements of wastewater treatment plants, oil separators, grease traps and dissolved air floatation units.
At the back end of this process, Hach Co. provides the tests -- from laboratory to on-line measurement -- to provide operators with the data needed to make informed changes to their process ensuring permit compliance.
“There is not a ‘one measurement fits all’ parameter,” says Mike Kilner, Hach’s applications development manager for industrial process and municipal wastewater. “By careful review of the waste stream we can determine the proper measurement method.”
But Hach tends to focus on chemical oxygen demand (COD), which it claims provides faster results than BOD testing. COD is a correlative/early indicator of BOD levels, and some permits include COD as a surrogate for BOD. (See our Hach Knowledge Center for more information).