Model tests on biogrouted granular columns in soft soil

This paper examines the possible use of a bio-cementation process to reduce excessive bulging that occurs during the loading of granular columns in soft clays. A 12-phase percolation biochemical treatment technique was used to bio-cement part of the columns targeting the columns upper section, where bulging usually occurs. Upon application of unit cell surface loads up to 350 kPa, placement of bio-cemented granular column substantially reduced the vertical strains by 43% to 48% compared with un-cemented granular column and 56% to 60% compared with unreinforced kaolin clay for just a low replacement ratio of 11%. Bulging was reduced by 62% to 75% following bio-cementation and mostly occurred where bio-cementation was less evident. Scanning electron microscopy and energy dispersive spectroscopy validated the existence of calcium carbonate. This study presents a relatively new alternative to reducing bulging in granular columns using a promising approach.

Distinctive IR-Spectroscopic Features of Functional Groups of Low-Grade Phosphorites After Microbiological and Acid Processing

The article discusses the current problems of enrichment of low-grade phosphorites by the thermal method as well as the production of mineral fertilizers using various acids. An alternative biotechnological method for producing organomineral fertilizers using neutrophilic, heterotrophic microorganisms of activated sludge at a biochemical treatment station for municipal wastewater for the processing of low-grade phosphorites and the production of phosphorus-containing organomineral fertilizers is proposed.In this case, a natural acceleration of the processes of the phosphorus cycle in nature occurs, which does not pollute the environment. A comparative description of IR spectroscopic descriptions of the results of microbiological treatment and treatment with sulfuric and nitric acids showed distinctive characteristics of the appearance of functional groups, which showed the transfer of valuable phosphorus components during acid treatment to sediment and their irrevocable loss in the form of waste.The studies will serve the utilization of low-grade phosphorites unused in the production, the production of a new type of organomineral fertilizer using and recycling of human waste (in most countries, incinerated), will lead to a gradual improvement in the structural composition of soils.Human vital activity waste and low-grade phosphorites have zero cost, the applied technology of biochemical treatment of domestic wastewater is available in all major cities that can be used to enrich phosphorites with organic matter.