Исследованы способы интенсификации анаэробного микробного разложения органической фракции твердых бытовых отходов (ТБО) на полигоне ТБО и в анаэробных реакторах. Установлено, что для инициации и стабилизации процесса анаэробной ферментации органических отходов в лабораторных биореакторах при 20 и 50°С в качестве инокулята предпочтительно использовать смесь активированной суспензии грунта анаэробной зоны полигона ТБО и сброженного в метантенке осадка сточных вод.

Methods of intensifying the anaerobic microbial decomposition of the organic fraction of municipal solid waste (MSW) on an MSW landfill and in anaerobic reactors were studied. It was discovered that it is preferable for the initiation and stabilization of the process of anaerobic digestion of organic waste in laboratory bioreactors at 20 and 50°C to use a mixture of activated suspension of soil from the anaerobic zone of the landfill and digested sewage sludge. Stimulation of methanogenesis was shown in field conditions when digested sewage sludge was added directly into the upper layer of anaerobic zone of the landfill. The investigation of methane production during fermentation of concentrated food waste with a mixture of excessive activated sludge in the laboratory under thermophilic conditions (50°C) has shown that the main problem at the first stage of the process was the acidification of the digested mixture due to the accumulation of volatile fatty acids. It was shown that for stable operation of the bioreactor under thermophilic conditions the amount of inoculum added during the start up should be no less than 30-50%—based on the total volatile suspended solids. A sharp decrease in the digestion temperature from 50 to 20°C did not cause methanogenesis termination, since the thermophilically fermented biomass contained both thermophilic and mesophilic methanogens.

Проведены исследования прикрепленного активного ила из станции очистки сточных вод в поселке Красная поляна (Сочи), реконструированной путем увеличения интенсивности аэрации и степени рецикла воды, а также установкой ершового носителя для иммобилизации активного ила. В биопленках активного ила, развившегося в условиях интенсивной аэрации, показано присутствие как аэробных, так и анаэробных микроорганизмов. Выявлено функционирование строго анаэробного метаногенного микробного сообщества, способного разлагать органические соединения с образованием метана, который далее окисляется аэробными метанотрофами. Летучие жирные кислоты, промежуточные продукты анаэробной деградации сложных органических соединений, используются аэробными и анаэробными микроорганизмами. В биопленках прикрепленного ила обнаружено анаэробное окисление аммония нитритом (анаммокс-процесс) и присутствие облигатно анаэробных анаммокс-бактерий. Одновременное осуществление аэробной и анаэробной деградации органических загрязнений прикрепленным активным илом позволяет достигать высоких скоростей очистки воды, устойчивости активного ила к меняющимся условиям внешней среды, а также уменьшает прирост избыточного ила.

Attached activated sludge from the Krasnaya Polyana (Sochi) wastewater treatment plant was studied after the reconstruction by increased aeration and water recycle, as well as by the installation of a bristle carrier for activated sludge immobilization. The activated sludge biofilms developing under conditions of intense aeration were shown to contain both aerobic and anaerobic microorganisms. Activity of a strictly anaerobic methanogenic community was revealed, which degraded organic compounds to methane, further oxidized by aerobic methanotrophs. Volatile fatty acids, the intermediates of anaerobic degradation of complex organic compounds, were used by both aerobic and anaerobic microorganisms. Anaerobic oxidation of ammonium with nitrite (anammox) and the presence of obligate anammox bacteria were revealed in attached activated sludge biofilms. Simultaneous aerobic and anaerobic degradation of organic contaminants by attached activated sludge provides for high rates of water treatment, stability of the activated sludge under variable environmental conditions, and decreased excess sludge formation.

This work studied the formation of molecular nitrogen by the microbial population of immobilized activated sludge of the domestic wastewater treatment plants (WWTP) that employ the technology developed by ZAO ECOS Company. The technology includes physicochemical water pretreatment and treated water recycling. A hard flexible fibrous brush carrier is used for the immobilization of microorganisms. The presence of both aerobic and anaerobic microorganisms and functioning of the methanogenic microbial community was shown in the biofilms developing on the carrier fibers and in suspended sludge. The high efficiency of nitrogen removal at a low C/N ratio was established to be due to the conjugated nitrification, denitrification, and anammox processes, whose functioning was demonstrated by laboratory cultivation methods and by studying the processes in batch and continuous reactors. Fluorescence in situ hybridization with 16S rRNA-targeted oligonucleotide probes (FISH) revealed bacteria belonging to the order Planctomycetales, particularly their anammox group. This work is the first evidence of the important role of the anammox process in the combined system of physicochemical and biological treatment of weak wastewater (BCDEAMOX).

The enumeration of methanotrophic bacteria in the cover soil of an aged municipal landfill was carried out using (1) fluorescent in situ hybridization (FISH) with horseradish peroxidase-labeled oligonucleotide probes and tyramide signal amplification, also known as catalyzed reporter deposition-FISH (CARD-FISH), and (2) most probable number (MPN) method. The number of methanotrophs was determined in cover soil samples collected during April-November 2003 from a point with low CH(4) emission. The number of types I and II methanotrophs obtained by CARD-FISH varied from 15 +/- 2 to 56 +/- 7 x 10(8) cells g(-1) absolute dry mass (adm) of soil and methanotrophs of type I dominated over type II. The average number of methanotrophs throughout the cover soil profile was highest during May-September when the cover soil temperature was above 13 degrees C. Methanotrophs accounted for about 50% of the total bacterial population in the deepest cover soil layer owing to higher availability of substrate (CH(4)). A lower number of methanotrophs (7 x 10(2) to 17 x 10(5) cells g(-1) adm of soil) was determined by the MPN method compared to the CARD-FISH counts, thus confirming previous results that the MPN method is limited to the estimation of the culturable species that can be grown under the incubation conditions used. The number of culturable methanotrophs correlated with the methane-oxidizing activity measured in laboratory assays. In comparison to the incubation-based measurements, the number of methanotrophs determined by CARD-FISH better reflected the actual characteristics of the environment, such as release and uptake of CH(4), temperature, and moisture, and availability of substrates.

Methane oxidation in the cover soil of the Khmet'evo municipal landfill in Moscow oblast was investigated. Methane emission from the experimental site of the landfill was highly heterogeneous. At a depth of 45–60 cm, the pore gas mainly consisted of CH4 (60–70%) and CO2 (30–40%). In the upper layers of the cover soil, the concentration of these gases sharply decreased. Methods for estimation of the methane-oxidizing activity in the cover soil of the landfill were tested. The rate of methane oxidation in the soil correlated with the cell number of culturable methanotrophic bacteria and was the factor limiting methane emission from the surface of the landfill. The method of indirect immunofluorescence revealed ten known species of methanotrophic bacteria in enrichment cultures obtained from samples of the cover soil. Our results also indicate the presence of unknown psychrotolerant methanotrophs that are active at the low temperatures characteristic of Moscow oblast.

Landfills and dumps are important sources of atmospheric methane. There is no generally accepted estimate of the influence of methane oxidation on landfill methane emissions. The present work aimed to analyse different methods for the investigation of methane emission and oxidation in methane-producing environments (wetlands, landfills, sludge checks), and to develop the precise procedure for the landfills. The combination of geochemical and microbiological methods to estimate and monitor the oxidation and emission of methane in landfills during different seasons is proposed. It includes the measurements, both on the surface and at different depths (up to 1 m) of landfill ground of the following parameters: (1) concentrations of methane, carbon dioxide and oxygen; (2) quantity of 13C isotope in gas samples; (3) methane-oxidation activity of landfill grounds assayed with two different methods: (a) in conditions of no moisture or substrate limitations, and (b) in conditions with a minimal deviation to in situ conditions; (4) the density of methanotrophic microbial population.

Methanogenic and methane-oxidizing activities of the microbial population of sewage sludge checks (Moscow and Syktyvkar regions) were studied at temperatures ranging from 5 to 25 degrees C. The number of methanogens in silt samples reached 10(10) cells/ml. A temperature decrease from 25 to 5 degrees C led to a sharp decrease of methanogenesis in the silt samples. Nevertheless, methanogenesis was still significant even at 5 degrees C. Different organic substrates, including polymeric and aromatic compounds, were degraded with methane production at 6 degrees C. At depths of 20-40 cm the number of methanotrophic bacteria reached 10(11) cells/ml. Methane oxidative activity of the microbial populations in the silt was less sensitive to the 25 degrees to 5 degrees C temperature decrease. Ten methanotrophic species, able to grow at 6 degrees C, were enriched from the Syktyvkar sludge lagoon and identified by indirect immunofluorescence. Enrichments obtained from the Syktuvkar region (62 N) contained more species of methane oxidizing bacteria able to grow at low temperature then methanogenic enrichments obtained from Moscow region (56 N).

The results obtained during the first year of execution of a joint Russian-Dutch project “The development of integrated anaerobic-aerobic treatment of liquid manure streams with maximisation of production of valuable by-products (fertilisers, biogas) and re-utilisation of water” (1999–2001) are discussed. The application of a straw filter was an effective means to separate the solid and liquid fractions of diluted pig manure wastewater and resulted in the removal of a significant part of the dry matter, total nitrogen and phosphorus (65, 27 and 32%, respectively). From the filtrate generated, 60–80 % of the COD was removed in a UASB reactor operating at 20–30°C. Up to 66% of phosphate was precipitated after air stripping of the CO2 from the anaerobic effluents. Ammonia was efficiently removed (>99%) from the anaerobic effluents using zeolite (Ural laumantite) as an ion exchanger. However, the N-content of the resulting zeolite was too low to be used as a fertiliser. A feasible alternative for nitrogen elimination involved nitrification of the anaerobic effluent followed by denitrification in a UASB reactor using the COD of the filtrated manure wastewater as carbon source.

Methanogenic and methane-oxidizing activities of the microflora of the Lyublino filter field (Moscow) were studied at temperatures ranging from 5 to 25 degrees C. The number of methanogens in sludge samples reached 10(10) cells/ml. The rate of methanogenesis was maximal at depths of 40-60 cm. The dependence on temperature of methane production was exponential, whereas that of methane oxidation was linear. At depths of 20-40 cm, the number of methanotrophic bacteria was 10(10)-10(11) cells/ml. Eleven methanotrophic species, five of which were able to grow at 6 degrees C, were identified by the method of indirect immunofluorescence. The microbial community of sludge checks also involved psychrophilic hydrogen- and CO-oxidizing bacteria, which resided in the aerobic zone of sewage sediments. The psychrophilic microflora forms a biological filter that reduces emissions of methane and other gases into the atmosphere.

Large fields for burying solid domestic wastes occupy more than 140 thousand hectares in the Soviet Union. Microbiological decomposition of organic components of domestic wastes under anaerobic conditions leads to biogas formation (60-65% of CH4, 30-35% of CO2) which migrates into enclosing rocks, underground waters, is partially oxidized in an aerobic zone and is relieved into the atmosphere. The composition of carbon stable isotopoes of methane and carbonic acid in biogas of deep layers of domestic wastes fields is typical for methanogenase of organic wastes, however it depends on the concentration of organic substance in the ground of solid domestic wastes and on the age of burial. Due to the oxidation processes in the upper layer methane gets lighter. and carbonic acid - heavier. Methanogenic microflora is represented by mesophilic bacteria, methanosarcina being one of the leading forms. In 10-100 cm depth from the surface an intensive oxidation of methane, hydrogen and carbonic acid is observed. The quantity of bacteria which oxidize gases makes up 10(6)-10(11) cells in a gram of soil. They are represented by bacteria of the genera: Methylomonas, Methylobacter, Methylosinus, Methylocystis, Methylococcus, Alcaligenes, Pseudomonas, Paracoccus, Mycobacterium. In small dumps methane was shown to be totally oxidized in an aerobic zone without any release into the atmosphere. Gas anomaly takes place mainly due to the emission of carbonic acid. On large dumps, in an upper ground layer, up to 50% of methane can be oxidized, which is formed in an anaerobic zone. Intensity of gas emissions is rather unevenly distributed throughout the surface of dumps of domestic wastes. The flow rates of biogas components which we have determined, vary (in 10(-4) m3/m2 hour-1) from 0 to 20,46, 7.5, 1.2 for CH4, CO2, H-2, CO respectively.The observed season variations of gas flows to a great extent depend on the activity of gas-oxidizing microflora, which is 3-5 times less active under psychrophilic conditions than under mesophilic ones. Production of biogas from dumps of domestic wastes in important not only as an additional source of energy, but also as a method of preventing pollution of Earth's atmosphere.

The methanogenic activity of manure destructors was investigated at different stages of cattle manure utilization at 35 degrees in a three-section horizontal methane tank manufactured by "Enbom" company (Finland). The association of microorganisms was found to have the highest activity at the last stage of the process, while the least activity was observed in case of fresh manure. A considerable increase of the methanogenic activity in the methane tank was proved by the radioisotopic method and by calculation of the population size of microorganisms from different groups by the series dilution method. Acetic and propionic acids were absent in samples from the third section of the methane tank, while the maximum concentration of the acids was found in the manure storage and in the first section of the methane tank. A significant part of active methanogenic microorganisms was removed with the effluent. Therefore, partial recirculation of the biomass should be used to increase the efficiency of the methane tank.