Introducing a New Media for Fixed-Film Treatment in Decentralized Wastewater Systems

Both naturally occurring and artificial media have been used to treat wastewater in small community settings. Systems using naturally occurring media include sand filters and peat-based biofilters. Artificial media include open cell foam, textiles, and plastics. All the above operate as fixed-film systems, in that attached growth microorganisms are encouraged to colonize and reproduce in the media. Fixed film systems appear to produce a more consistent effluent under peaked sewage inputs and periods of no use (vacation homes, weekend retreats) compared to suspended growth systems in this flow range. Naturally occurring media have advantages in that naturally occurring fauna and flora may already be present in the media. Start up is therefore shortened because colonists are already present in the media and just need to multiply to handle the waste renovation process. A disadvantage of naturally occurring media is that they must be mined. Extraction of these natural resources is sometimes criticized because they formed over thousands of years. They will eventually be exhausted and will not be replaced. Quanics. Inc. has patented a product that combines advantages of both artificial and naturally occurring media. The Bio-COIR™ filter uses coir, the recycled husks of coconut in a biological fixed film filter. The material is a waste product of agricultural operations in developing countries. The product has successfully passed NSF Standard 40 certification. Systems in the ground for two years show virtually no change in media properties except a slightly darker color, giving the expectation that the media will continue to function for a comparable period to peat (8 to 16 years between media replacement).