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Using biogas instead of fossil fuels decreases pollutants such as solid particles, sulphur dioxide, nitrogen oxides concentrations in the environment. Green energy and development of relevant infrastructure improves air quality considerably. Chemical, physical, biological methods are used for biogas purification. The main difficulties using biological methods are selection of suitable microorganisms' suspensions and making optimal conditions in photobioreactor. Different origin and structure microalgae suspensions are used applying biological treatment methods. Monoraphidium griffithi, which is widespread in fresh water, has relatively high potential. Microalgae’ cultures absorb the main components of biogas - carbon dioxide (CO2) and hydrogen sulphide (H2S). Absorbtion processes are based on photosynthesis. Microalgae absorb specific components of biogas when there are suitable light source and nutrient solvent. The main purposes of the research are to asses emission of biogas using different substrates (chicken manure and wastewater sludge). Also, it was measured main physical and chemical characteristics of both substrates: acidicy, temperature, redox potential, conductivity, biohemical oxygen demand. According results of the research, emission from wastewater sludge is greater than from chicken manure so sludge was chosen in teh next stage of the research. The next stage - asssessment of purification efficienty using Monoraphidium grifftihii suspension. Raw biogas was supplied to photobioreacor (with microalgae suspension). Alterations of methane, carbon dioxide, oxygen, hydrogen sulphide concentrations were measured precisely. According to results concentration of methane in the beginning of the researc was 62%, after 35 days - 69%. Meanwhile carbon dioxide - 37% and 31% by analogy. Experimental research alows to assess Monoraphidium griffithi absorption capacity of ballast components. Results were compared to different scientists' results which were present in scientific journals and publications. Comparative analysis alows to assess practical possibilities to use Monoraphidium griffithi as biological treatment of raw biogas. [ABSTRACT FROM AUTHOR]

Volatile organic compounds, e. g. acetone, have a direct impact on climate change, decrease of ozone in the air, and on the growth of greenhouse effect. One of the most popular air purifying methods from VOC is a biological air cleaning. Experimental investigations were conducted to determine the efficiency of the new structure of biofilter with polypropylene plates segments. During the investigations the efficiency of segmental construction biofilter of air purification at different initial concentrations of pollutants was determined. Different concentrations of pollutants were estimated during the acetone dilution with water. During the tests the efficiency of biofilter air purification from acetone vapor and its change under different concentrations of vapors was set. Based on test results, the maximum efficiency of biofilter air purification was up to 93%. Studies have shown that increasing the allowable pollutant concentration, the efficiency of air purification unit decreases. Increasing the concentration of supplied acetone vapor into the biofilter from 232 to 701 mg/m3, cleaning efficiency decreased from 92.8 to 82.3%. Since microorganisms fail to oxidize organic compounds, the filter works better at lower initial concentrations of pollutants. [ABSTRACT FROM AUTHOR]

Experimental studies have been carried out using an adsorber - a constructed laboratory bench. Zeolite, a natural mineral, has been selected as a charge. This aluminosilicate of a crystalline structure is resistant to high temperatures, aggressive mediums and the impact of radiation. Zeolite is ecologically clean, inert and non-toxic material, which fully suits to be used in most industrial, agricultural, environment fields and at home for eliminating the consequences of ecological accidents etc. For the purification of contaminated biogas, the laboratory adsorber is equipped with three sections filled up with 10 cm of adsorbing material the efficiency of which is established after every filtration column (10 cm, 20 cm and 30 cm). The studies have been carried employing two different contaminants - sulphur hydrogen (H2S) and ammonia (NH3). It has been established that, with a high concentration of sulphur hydrogen, the efficiency has amounted to 96.1% while the degree of ammonia purification has reached 95.4%,when NH3 concentration in biogas is 24.0 mg/m³. [ABSTRACT FROM AUTHOR]