[Microorganisms in heat supply lines and internal corrosion of steel pipes]. / Mikroorganizmy v teplovykh setiakh i vnutrenniaia korroziia stal'nykh truboprovodov.

In laboratory experiments with batch cultures of thermophilic microorganisms isolated from urban heat supply systems, the growth of sulfate-reducing, iron-oxidizing, and iron-reducing bacteria was found to accelerate the corrosion rate of the steel-3 plates used in the pipelines. In the absence of bacteria and dissolved oxygen, minimal, corrosion was determined. The aforementioned microorganisms, as well as sulfur-oxidizing bacteria, were found to be widespread in water and corrosion deposits in low-alloy steel pipelines (both delivery and return) of the Moscow heat networks, as well as in the corrosion deposits on the steel-3 plates in a testing unit supplied with the network water. The microorganisms were found in samples with water pH ranging from 8.1 to 9.6 and a temperature lower than 90 degrees C. Magnetite, lepidocrocite, goethite, X-ray amorphous ferric oxide were the corrosion products identified on the steel-3 plates, as well as siderite, aragonite, and S0. The effect of microbiological processes on the rate of electrochemical corrosion was evaluated from the accumulation of corrosion deposits and from variation in total and local corrosion of the steel plates in a testing unit.

[Microbiological processes in a high-temperature oil field]. / Mikrobiologicheskie protsessy v vysokotemperaturnom neftianom mestorozhdenii.

Thermophilic sulfate-reducing bacteria (SRB) oxidizing lactate, butyrate, and C12-C16 n-alkanes of oil at a temperature of 90 degrees C were isolated from samples of water and oil originating from oil reservoirs of the White Tiger high-temperature oil field (Vietnam). At the same time, no thermophiles were detected in the injected seawater, which contained mesophilic microorganisms and was the site of low-temperature processes of sulfate reduction and methanogenesis. Thermophilic SRB were also found in samples of liquid taken from various engineering reservoirs used for oil storage, treatment, and transportation. These samples also contained mesophilic SRB, methanogens, aerobic oil-oxidizing bacteria, and heterotrophs. Rates of bacterial production of hydrogen sulfide varied from 0.11-2069.63 at 30 degrees C and from 1.18-173.86 at 70 degrees C micrograms S/(1 day); and those of methane production, varied from 58.4-100 629.8 nl CH4/(1 day) (at 30 degrees C). The sulfur isotopic compositions of sulfates contained in reservoir waters and of hydrogen sulfide of the accompanying gas indicate that bacterial sulfate reduction might be effective in the depth of the oil field.