With this demonstration project Biotec Sys and UNIBO, with the support of the Emilia Romagna Region, built from 1988 to 1993 a large aquatic system for the treatment of pig manure combined with the production of biomass for feed purposes.

A three-stage sequential process was developed: microalgae, zooplankton and floating aquatic plants for the complete treatment of the sewage.

The anaerobically digested for biogas production and clarified slurry fed an equalization tank to be then added to several mechanically mixed high-rate algal raceways.

Then the effluent from the algal reactors fed a series of basins in which the microalgae were removed by periodically collected cladocera and rotifers; the effluent was found to be suitable for the cultivation of floating aquatic plants which also were periodically harvested to be transformed as well as the zooplankton into specific foods for fish.