Evaporation of liquids at low temperatures

Ukrainian enterprises annually generate millions cubic meters of mineralized water, which is discharged into surface reservoirs, and millions cubic meters of highly concentrated solutions and suspensions, which are accumulated and stored in special sludge storages. This waste water causes irreparable damage to the environment. A new method for the evaporation of industrial concentrates by fibrous materials with capillary properties was proposed not so long ago. The use of such materials allows an effective, autonomous, cheap, and extremely simple system to be created for the evaporation for various liquids and concentrates. The research methodology was as follows. Two graduated cylinders of the same diameter were used in our research. One cylinder was filled with the liquid phase to a certain level and used to control evaporation from the surface of the aqueous medium. In the other, experimental cylinder, a vertical cotton strip was additionally placed (from 1 to 21 layers of fabric). The width of the strip was 5 cm. The length of the strip was 50 cm. The density of cotton was 100 g/m2. The research method was to determine the height of liquid phase capillary rise along the strip of fabric and to evaluate reduction in the volume of liquid that evaporates in both cylinders at set temperatures. It was found that in the absence of wind and the distance between the vertically placed strips of 7–15 mm were sufficient to ensure the maximum evaporation intensity. Our long-term experiments in natural conditions confirmed the high efficiency of the proposed method. At an average daily air temperature of 2.3 °C, there was a significant evaporation from the surface of the fabric during the day. In this case, evaporation from the water surface was not observed. It should be noted that the intensity of evaporation under natural conditions depends on a significant number of factors (temperature, wind speed, luminosity, humidity, etc.), so it is difficult to detect a direct relationship between some of them. With increase only in the liquid phase temperature, the evaporation efficiency decreased. At a temperature of 20 °C, the laboratory installation (15 layers of cotton strip) increased the evaporation intensity by more than 2 times, at 46 °C by more than 5 times, at 57 °C by almost 3 times, but at 75 °C only by about 67 %. It is obvious that heating of the liquid phase alone less influences the evaporation process from the surface of the fabric strip, which was cooled rapidly in the atmosphere at a much lower temperature. Therefore, to increase the evaporation intensity, it is necessary to increase temperature for all components of the liquid–fabric system. A fabric with suitable properties, stretched between two metal racks and immersed into the liquid phase with the lower end, can be used as a simple evaporator. Our research has shown that the use of materials with capillary properties in the treatment of liquid solutions allows simple, cheap, and efficient devices to be created for evaporating water and converting liquid waste into a solid phase.

Organic Matter Decomposition in River Ecosystems: the Role of Microbial Interactions Regulated by Environmental Factors

Microbes are the critical contributors to the organic matter decomposition (OMD) in river ecosystems. However, the role of microbial interactions on the OMD in river ecosystems and the regulation of environmental factors to the microbial interactions were not considered previously thus tacked in this study. Cotton strip (CS) as a substitute for organic matter was introduced to Luanhe River Basin in China. The results indicated that CS selectively enriched bacterial and fungal groups related to cellulose decomposition, leading to the cotton strip decomposition (CSD). In these groups, bacterial phyla Proteobacteria, fungal phyla Rozellomycota and Ascomycota were the dominant groups associated with the CSD. Bacteria and fungi on CS cooperatively formed a co-occurrence network to achieve the CSD. In the network, the key modules 2 and 4, mainly composed of phyla Proteobacteria and Ascomycota, directly promoted the CSD. Keystone taxa maintained the stability of microbial network structure and function, and regulated microbial groups associated with CSD in the key modules, rather than directly decomposing the CS. Notably, this study profoundly revealed that water temperature and total nitrogen (TN) regulated the keystone taxa and key modules in microbial interactions and then promoted the OMD. The two key modules 2 and 4 were significantly correlated with water temperature and TN in water, and two keystone taxa (bacterial genera Emticicia and Flavihumibacter) were significantly associated with TN. The research findings help us to understand the microbial mechanism of the OMD in rivers, which provides valuable insights into improving effective management strategies for river ecosystems.

Quantifying the response of a functional indicator of ecosystem health to disturbance gradients in New Zealand riverine environments: a meta-analysis

<p><b>In New Zealand, recent policy changes require freshwater managers to take more comprehensive and integrated approaches to monitoring and maintaining ecosystem health. To attempt to prevent and reverse the adverse effects of land use change on freshwater ecosystems, management decisions need to be based upon a suite of indicators each with a strong foundation of knowledge regarding the nature of responses at a national scale. Monitoring ecosystem function in addition to structural indicators has long been suggested to provide a more accurate and holistic narrative of ecosystem health, however, it has yet to be adopted in routine bioassessment. The cotton strip assay has shown promise as a consistent, relatively cheap, and repeatable method for monitoring freshwater ecosystem function, indicating the ecological processing rates of riverine microbial communities and the organic matter processing potential of riverine environments. Numerous regional-scale studies have applied the cotton strip assay in New Zealand, but these data have yet to be explored in unison. For managers to successfully monitor, manage, and restore ecological processes in river environments, a comprehensive understanding of the proximate drivers of cotton breakdown is needed. The aim of this study is to conduct a meta-analysis of cotton strip assay data to explore the relationship between river function and other measures of ecosystem health and land-use stressors at a national scale.</b></p> <p>I collated published and unpublished cotton strip data to create a meta-dataset, with measures harmonised by deployment time and temperature for more meaningful comparisons at a national scale. I sourced additional data from national databases describing water quality and physical river classification information for more comprehensive, higher resolution analyses. I then used the meta-dataset was to investigate the nature of cotton decomposition responses along varying levels of impairment across different seasonal conditions and spatial catchment attributes. </p> <p>I used linear mixed-effects models to determine the relationships between cotton decomposition and physicochemical predictor variables, along with any additional influence attributed to underlying spatial variation across sites. Results suggest that bioavailable nutrients and water clarity are the largest drivers in cotton breakdown rates at a national scale. Water temperature and seasonal conditions emerged as likely limiting factors on microbial activity and cotton breakdown, indicating that consistent intra-seasonal monitoring is advisable. Climate and underlying geology can also be important when looking to discriminate underlying catchment variation and should be incorporated when making larger scale comparisons. Relationships with land use were found to be non-linear and likely to have too many co-varying factors enacting influence on cotton breakdown rates to be successful predictive gradients. Breakdown responses were, however, most consistent under high levels of vegetation cover, and high variability in responses in more urban and pastoral developed catchments. The assays’ sensitivity to nutrient enrichment at a national scale could aid in informing management policies with respect to nutrient limits, and the setting of natural ecosystem processing benchmarks.</p>

Quantifying the response of a functional indicator of ecosystem health to disturbance gradients in New Zealand riverine environments: a meta-analysis

<p><b>In New Zealand, recent policy changes require freshwater managers to take more comprehensive and integrated approaches to monitoring and maintaining ecosystem health. To attempt to prevent and reverse the adverse effects of land use change on freshwater ecosystems, management decisions need to be based upon a suite of indicators each with a strong foundation of knowledge regarding the nature of responses at a national scale. Monitoring ecosystem function in addition to structural indicators has long been suggested to provide a more accurate and holistic narrative of ecosystem health, however, it has yet to be adopted in routine bioassessment. The cotton strip assay has shown promise as a consistent, relatively cheap, and repeatable method for monitoring freshwater ecosystem function, indicating the ecological processing rates of riverine microbial communities and the organic matter processing potential of riverine environments. Numerous regional-scale studies have applied the cotton strip assay in New Zealand, but these data have yet to be explored in unison. For managers to successfully monitor, manage, and restore ecological processes in river environments, a comprehensive understanding of the proximate drivers of cotton breakdown is needed. The aim of this study is to conduct a meta-analysis of cotton strip assay data to explore the relationship between river function and other measures of ecosystem health and land-use stressors at a national scale.</b></p> <p>I collated published and unpublished cotton strip data to create a meta-dataset, with measures harmonised by deployment time and temperature for more meaningful comparisons at a national scale. I sourced additional data from national databases describing water quality and physical river classification information for more comprehensive, higher resolution analyses. I then used the meta-dataset was to investigate the nature of cotton decomposition responses along varying levels of impairment across different seasonal conditions and spatial catchment attributes. </p> <p>I used linear mixed-effects models to determine the relationships between cotton decomposition and physicochemical predictor variables, along with any additional influence attributed to underlying spatial variation across sites. Results suggest that bioavailable nutrients and water clarity are the largest drivers in cotton breakdown rates at a national scale. Water temperature and seasonal conditions emerged as likely limiting factors on microbial activity and cotton breakdown, indicating that consistent intra-seasonal monitoring is advisable. Climate and underlying geology can also be important when looking to discriminate underlying catchment variation and should be incorporated when making larger scale comparisons. Relationships with land use were found to be non-linear and likely to have too many co-varying factors enacting influence on cotton breakdown rates to be successful predictive gradients. Breakdown responses were, however, most consistent under high levels of vegetation cover, and high variability in responses in more urban and pastoral developed catchments. The assays’ sensitivity to nutrient enrichment at a national scale could aid in informing management policies with respect to nutrient limits, and the setting of natural ecosystem processing benchmarks.</p>

Is cotton-strip tensile strength a surrogate for microbial activity in groundwater?

The cotton strip assay uses the loss of tensile strength of cotton strips as a measure of microbial cellulolytic activity. Its suitability for measuring general microbial activity in groundwater was tested by examining the relationship of tensile strength, abundance of cellulolytic organisms and general microbial activity on cotton strips deployed in bores. The hypothesis was that the strength of cotton strips would decline with increasing abundance and activity of cellulolytic organisms, and as cellulolysis makes resources available to other microbial groups, cotton strength loss should also be related to increased overall microbial activity. The correlation between the abundance of cellulolytic organisms and cotton strength was not significant. Two main factors influenced this relationship: (i) effectiveness of the media in detecting cellulolytic moulds and (ii) inter-community interactions. After accounting for the presence of moulds through partial correlation, the relationship between tensile strength and abundance of cellulolytic organisms was stronger and significant. Both cotton strength and abundance of cellulolytic organisms correlated significantly with general microbial activity. These results support the use of the cotton strip assay, and cotton tensile strength as a surrogate for microbial activity in groundwater.