Bibliometric Analysis of Research Trends Related to Carbon Sources for Nitrogen Removal in Wastewater Treatment

The low organic carbon content of municipal wastewater weakens the effectiveness of biological nitrogen removal. Here, we review recent trends in carbon sources for nitrogen removal during wastewater treatment. A bibliometric analysis, using the Science Citation Index Expanded database from the Web of Science, was performed to analyze articles published in this field from 2000 to 2019. The major points are the following: (1) the publications from China ranked 1st, followed by the USA and Japan during the statistical period. In terms of research institutions, the Chinese Academy of Sciences was the largest contributor with the most publications. (2) Based on the trend analysis of keywords, future research hotspots are discussed, showing that of the related research on external carbon sources, the research focus on traditional carbon sources (methanol, ethanol, etc.) has decreased. The research focused on alternative carbon sources, such as sludge hydrolytic acidification liquid, fermentation liquid of food waste, agricultural waste, and biodegradable polymers, has increased. (3) New nitrogen removal technologies without external carbon sources, such as anammox is becoming increasingly popular. (4) In the study of nitrogen removal, more attention is paid to the change in the microbial community, and the biological mechanism of nitrogen removal is discussed from a microscopic perspective.

Soil Fertility Properties, Leaf Nutrient Status and Yield Of Coconut and Intercrops as Influenced and Coconut Based Cropping System in Coastal Plain of Western India

An experiment was conducted during 2013 -2019 to study the impact of intergrated nutrient management through organic matter recycling (OMR) on the soil properties, leaf nutrient status and yield of coconut and its components crops at Regional Coconut Research Station (AICRP on Palms), Bhatye, Maharashtra, India. The experiment was laid out in 0.40 ha with four treatments namely T1, T2, T3 and T4. Results showed that, INM practices significantly improved the soil physico-chemical, biological properties and leaf nutrient status, whereas it was more prominent for the T1 treatment. The soil organic carbon content during post experimental period gradually increased in the organic recyclable treatment under cropping system (0.80 to 0.86%) compared to monocropping (0.60%). The recyclable biomass produced from the system varied between 9.0 - 18.0 t/ha/year and vermicompost produced was 4.8 to 10.2 t/ha/year by composting through earthworm. The nut yield (147.2 and 138.4 nuts/palm), copra output (25.75 and 23.06 kg/palm) and oil output (17.11 and 15.72 kg/palm) under treatment T1 and T2 were on par and differed significantly compared to monocrop. Bangladesh J. Bot. 50(4): 1067-1075, 2021 (December)

Effects of organic carbon content on in situ remediation time using steam–air injection

Groundwater contamination by chlorinated hydrocarbons (CHC) is a common phenomenon that poses health risks to both humans and animals. These halogenated hydrocarbons infiltrate into the soil matrices and form pools at the bottoms of the aquifers thus contaminating the groundwater sources. Thermally enhanced soil vapour extraction (TSVE) using steam–air injection has gained popularity as an alternative technique to remediate the saturated and vadose source zones contaminated with CHC. This technique has been successfully applied in the remediation of contaminated sites (brownfields, industrial sites) and groundwater. However, the presence of organic carbon (OC) contents within the soil matrices has not been intensively studied. This paper, therefore, intends to contribute toward increasing the understanding of the effects of OC on the remediation time using TSVE. A 2-D flume experimental model was conducted in VEGAS laboratory using coarse sand, fine sand and silty soil with 0, 1 and 2% addition of the activated carbon as OC to investigate the desorption time of PCE and TCE as CHC during TSVE extraction using steam–air injection. 100 kg of soil mixed with the activated carbon was treated with 50 g TCE and 50 g PCE and then remediated using TSVE. The remediation times were recorded and recovered CHC was documented. It was discovered that the presence of OC enhanced the adsorption of the CHC onto the soil matrices thereby increasing the time required for the complete remediation of the contaminant from the soil. An increase of OC by 1% resulted in desorption time by a factor of 4–7.

Morphological and physico-chemical properties of Cryosoils in the Bulgarian antarctic base on Livingston island, Antarctica

Under the global climatic changes and anthropogenic impacts on the environment, information about characteristics and specific features of soils in remote regions as Antarctica is valuable and could be used as references. This study focuses on the analyses of original data about the physico-chemical composition and micromorphological structure of Cryosols, collected in 2019 from the sampling area of the Bulgarian Antarctic Base “St. Kl. Ohridski” located on Livingston Island, Antarctica. The studied Cryosols are moderately acidic with slow and incomplete transformation of organic residues. The organic carbon content is low, except for soils formed under the influence of an ornithogenic factor. The mezo- and micromorphological observations show a predominance of the mineral phase, weakly affected by weathering processes. Many soil pores and voids are observed, which facilitates water-air and intra-soil exchange during the short Antarctic summer. The analyses showed an evidence for the connection of the processes of soil formation of Cryosols in the region with the pulsating degradation of the glaciers.

Bioinoculants—Natural Biological Resources for Sustainable Plant Production

Agricultural sustainability is of foremost importance for maintaining high food production. Irresponsible resource use not only negatively affects agroecology, but also reduces the economic profitability of the production system. Among different resources, soil is one of the most vital resources of agriculture. Soil fertility is the key to achieve high crop productivity. Maintaining soil fertility and soil health requires conscious management effort to avoid excessive nutrient loss, sustain organic carbon content, and minimize soil contamination. Though the use of chemical fertilizers have successfully improved crop production, its integration with organic manures and other bioinoculants helps in improving nutrient use efficiency, improves soil health and to some extent ameliorates some of the constraints associated with excessive fertilizer application. In addition to nutrient supplementation, bioinoculants have other beneficial effects such as plant growth-promoting activity, nutrient mobilization and solubilization, soil decontamination and/or detoxification, etc. During the present time, high energy based chemical inputs also caused havoc to agriculture because of the ill effects of global warming and climate change. Under the consequences of climate change, the use of bioinputs may be considered as a suitable mitigation option. Bioinoculants, as a concept, is not something new to agricultural science, however; it is one of the areas where consistent innovations have been made. Understanding the role of bioinoculants, the scope of their use, and analysing their performance in various environments are key to the successful adaptation of this technology in agriculture.