An environmental engineering approach to wastewater treatment with bivalves in the coastal zone

High tolerance to pollution and filtration capacity of some seston-eating bivalves and mussels of g. Mytilus first of all, principally determine mussel populations as a powerful natural biofilter. Both marine and freshwater mussels consume relatively large amounts of seston, feeding directly on the primary producers. Particles with contaminants extracted from ambient water during the filtration are accumulated in mussel pseudofaeces and faeces discharged after digestion. These specific particles of faeces and soft pseudofeaces become very suitable substrata for bacteria development with following contaminant destruction. Moreover, such biodeposits appeared to be the nutritious food for bottom detritophages, in particular of polychaetes and amphipods. Some fluid metabolites excreted by mussels, i.e. dissolved organic matter (DOM) have a pronounced biological activity to producers. In general, mussels possess high resistance to acute and chronic pollution stress, although their growth may slow down and even stops. In clean conditions food supply is the most important factor in determining activity and growth rate of mussels for northern environment. Mussel and some other aquaculture, as a relatively new application of environmental engineering is able to improve the recycling of nutrients from wastewater to bioproduction and greatly reduce the risk of environmental degradation in the coastal zone.