Abstract: Azolla filiculoides with very high biomass and reproductivity capacity has been used as a nourishing forage grass. By means of constructing shallow tanks on the rooftop, five year's experiments of cultivation of Azolla filiculoides were carried out since 1990 in the rural areas, northern China Azolla filiculoides had a relative high ecological and economical benefits. This technology can be used in Hebei province, south part of northeastern China and in the areas with rooftops.

Key words: engineering carbon nanomaterials, chemical transformation, photodegradation, biodegradation.