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UDC 628.336.098.4
Vanyushina A. Ya., Danilovich Dmitrii
Anaerobic digestion – the key technology of municipal wastewater sludge treatment (part 1)
Summary
The technologic options of municipal wastewater sludge treatment are considered with different approach to stabilization of organic matter. The technologic and environmental consequences of raw wastewater sludge landfilling are considered: emission of malodors, dewatered sludge re-thinning that entails re-dewatering are described. It is shown that traditional aerobic stabilization that was widely used last century does not meet the present day requirements both to power consumption and decomposition depth. The processes of autothermal thermophilic aerobic digestion and composting that provide for the production of safe and high-quality fertilizer from sludge are considered. It is concluded that the use of these processes is economically limited to the option of land utilization of the entire sludge volume. The issues of domestic approach to digestion that consist in using thermophilic mode with extremely low retention time of sludge in a digester are considered. The largest share of small particles in sludge digested by such technology caused numerous problems with dewatering in 1960–80-ies. The ways of solving these problems at the Kur’ianovo and Liubertsy wastewater treatment facilities in Moscow including the use of advanced dewatering equipment are described. It is concluded that in the XXI century anaerobic digestion of wastewater sludge in digesters does not have any other comparable alternative for large and mid-sized wastewater treatment facilities. The main trends in using digestion process, digester design, the methods of enhancing the process (thermal hydrolysis, disintegration, ultrasonic, phasing, recycling of digested sludge) are considered. The information on biogas properties is consolidated. (To be continued).
Key words
composting , anaerobic fermentation , sludge , stabilization , thermophilic digestion
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bbk 000000
UDC 628.336.71
Duambekov M. S., Ivanov A. N., Ivanova N. V.
«Organic belt around Kazakhstan cities – 2020» environmental project
Summary
The description of «Organic belt around Kazakhstan cities – 2020» environmental project that engages essentially the water industry and that is being implemented nowadays is presented. The timeliness of the project comes from the amendment of the national legislation, Article 301 of the Environmental Code of the Republic of Kazakhstan in particular (2016), that is related to the regulation of waste landfilling. The new regulatory document limits (and actually prohibits) storing dewatered wastewater sludge on landfills and prescribes to provide for its further processing with the purpose of transferring theses wastes from «hazardous organic wastes» category to recultivants, cultivation soil etc. The project envisages the use of Russian technology of wastewater sludge dewatering on sludge beds with the use of «Sibflok®» flocculant and the technology of enhanced composting of organic wastes developed by the experts of International Academy of Ecology (Astana). The implementation of this project will provide not only for reducing significantly the amount of municipal sludge transported to landfilling but also for establishing the production of soil-like substrates, soils for remediation of desertificated territories, landfills, dumps; and in case of advanced processing – for urban greening services.
Key words
composting , dehydration , flocculant , sludge beds , environmental damage , wastewater sludges , reclamation , bio-conversion , remediation of disturbed lands
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