I. ECOSYSTEMS AND BIODIVERSITY

Abstract. The present paper is aimed on the preparation of zeolites from lignite coal fly ash using a superior synthesis approach that combines the advantages of different established technological schemes. The novel method is directed to improvement of the energy efficiency and the raw material economy, and at the same time resulting in better quality material. Fly ash zeolites of Na-X type were synthesized applying fusion stage of fly ash/NaOH mixtures followed by atmospheric self-crystallization. The obtained zeolite structure was investigated by X-ray diffraction for different periods of crystallization of the reaction mixtures under atmospheric conditions. Comparative studies of three different methods for synthesis of Na-X were performed taking into account the specific energy and the raw material consumption. It was considered that adsorbents of zeolite X type can be obtained by different ways of alkaline conversion of coal fly ash, and that is why the most important issues for the scale production of these materials are the economical aspects of the synthesis.

Keywords: synthesis of zeolites; adsorption; carbon emissions

Abstract. The process of anaerobic ammonium oxidation (ANAMMOX) is carried out by newly discovered anammox bacteria. They have a number of morphological, physiological and biochemical properties that other bacteria lack. For use on construction sites of the Winter Olympics 2014 in Sochi, there has been developed a new biotechnology of wastewater treatment with immobilization of microbial activated sludge and efficient removal of nitrogen with the participation of anammox-bacteria, and has been created a compact, environmentally friendly wastewater treatment plants (WWTP) prefabricated in block structures. The principles of the new technology and the design of full-scale 100-1000 m³/day "BCH-ECOS" plants were based on the results of laboratory-scale microbiological studies and experimental-industrial trials that have confirmed the application perspectives of anaerobic ammonium oxidation (anammox). The new technology involves a pretreatment of incoming raw water by coagulation in order to precipitate the suspended solids. A significant part of phosphorus compounds is being precipitated at the same time. Aerated water, high in nitrate and nitrite, is recycled from the last corridor of aeration tank into the denitrifying reactor, which is located at the beginning of biological treatment and receives ammonia-rich water. Conditions for the development of nitrogen removing denitrifying and anammox-bacteria are thereby created in the anaerobic denitrifying bioreactor. Brush-shaped carrier is applied at all stages of biological treatment for immobilization of active microbial sludge. Treated water passes through the dense brush-shaped carrier filters and granular anthracite filters.  The quality of the treated water exceeds the requirements for discharging into water bodies.

Key words: anammox-bacteria, effective nitrogen removal, biotechnology of wastewater treatment, immobilized activated sludge

Abstract. DIAL method is proposed for determination of the abundance of atmospheric methane. The spectral properties of laser radiation of high- power pulsed laser diodes are optimised within the molecular absorption bands of 1.55- 1,625 mm of this major greenhouse gas. The characteristic broad laser line of the selected laser diodes modulated by the selected explicit absorption spectrum is explored by computational convolution based on HITRAN reference data on spectral linestrengths. The lidar scheme is ultimately compact, of low- energy consumption and suggests a large potential for ecological monitoring.

Keywords: Ecological monitoring, atmospheric methane, powerful laser diodes

POWER GENERATION USING MODIFIED CATHODES IN AIR-CATHODE MICROBIAL FUEL CELL

Blagovesta Midyurova, Bogdan Bonev, Valentin Nenov