The biotechnological ways of blue-green algae complex processing

Abstract

The results of long­term research of various ways and methods of collection and processing of blue­green algae that cause “bloom” of the Dnieper reservoirs were presented. The possibility and feasibility of the blue­green algae biomass processing to biogas by methanogenesis were substantiated. It was found experimentally that preliminary mechanical cavitation of the blue­green algae biomass increases the biogas yield by 21.5 %. It was determined that the biogas produced contains up to 72 % of methane and hydrogen, up to 21 % of carbon dioxide, up to 6.5 % of molecular nitrogen. Oxygen, carbon oxide (II), hydrogen sulfide and other impurities constitute up to 2 % of the biogas volume. Biotesting of the spent substrate to determine its toxicity for further use as a biofertilizer in agriculture and forestry was held. Modern methods of electron microscopy found that the average diameter of cells of blue­green algae Microcystis aeruginosa is 3.14 microns. The flow diagram of the blue­green algae biomass complex processing was proposed. It consists in removal of valuable components for medicine, cosmetics, pharmaceu ticals, production of technical detergents, mixtures of aliphatic alcohols as biofuels or additives to gasoline. Thus, it is possible to obtain more biogas by involving the spent activated sludge from sewage treatment facilities in methanogenesis. This will improve the treatment quality of wastewater of various productions. The similarity of the nutritional value of the blue­green algae spent substrate to the green biomass of plants in terms of the elemental composition was experimentally proved. The environmental, energy saving and agricultural efficiency of the cyanogen biomass use was proved.