Application of Calcium-rich Clay Mineral Under Nonwoven Fabric Mats and Sand Armor as Cap Layer for Interrupting N and P Release from River Sediments

This work investigates the applicability of thermally treated calcium-rich clay minerals (CRCMs), such as sepiolite (SPL), attapulgite (ATT), and dolomite (DLM) to hinder the nitrogen (N) and phosphorus (P) release from river sediments. A non-woven fabric mat (NWFM) or a sand layer were also capped as armor layers, i.e., placed over CRCMs to investigate the capping impact on the N/P release. The capping efficiency was evaluated in a cylindrical reactor, consisting of CRCMs, armor layers, sediments, and sampled water. We monitored N/P concentrations, dissolved oxygen (DO), oxidation reduction potential, pH, and electric conductivity in overlying water over 70 days. The DO concentrations in the uncapped and capped conditions were preserved for 30 days and 70 days (until the end of experiment duration), respectively. ATT showed higher efficiency for NH4-N and T-N than the other two materials, and the capping efficiency of NH4-N was measured as 96.4%, 93.7%, and 61.6% when capped with 2 cm sand layer, 1 cm sand layer, and NWFM layer, respectively. DLM showed a superior rejection capability of PO4-P to ATT and SPL, reported as 97.2% when capped with 2 cm sand armor. The content of weakly adsorbed-P was lower in the uncapped condition than in the capping condition. It can be concluded that ATT and DLM can be used as capping agents to deactivate N and P, respectively, to reduce water contamination from sediments of the eutrophic river.

Experimental flooding modifies rhizosphere conditions, induces photoacclimation and promotes antioxidant activities in Rhizophora mucronata seedlings

Survival of mangrove seedlings under flooding depends on their tolerance and adaptation. This study investigated the effects of flooding on rhizosphere conditions: porewater dissolved oxygen (DO), pH, and soil oxidation–reduction potential (ORP) and photosynthetic and antioxidant activities (superoxide dismutase [SOD] and guaiacol peroxidase [POX] activity and glutathione [GSH] content) of Rhizophora mucronata seedlings. The experiment lasted 20 days with three treatments: control (with drainage), waterlogging (10 cm of water above the soil surface) and submergence. Our results demonstrate that waterlogging and submergence resulted in a reduction in porewater DO, pH and soil ORP from day 5 into the treatment. Submergence resulted in lower maximum electron transport rates, lower saturating irradiance and higher light utilization efficiency from day 5 onwards, but stomatal closure was detected in both flooded treatments. POX activity and GSH content in the roots were increased by submergence. On day 5, submerged plants showed higher root POX activity than the other two treatments and higher root GSH content than controls. However, these parameters decreased on day 20, so that no difference among the treatments remained. As persistent flooding was shown to hamper the physiological performance of mangrove seedlings, extreme weather events and sea-level rise should be closely monitored.

Disinfection of Dental Chair Water Using Aqueous Chlorine Dioxide

Chlorine dioxide is a safe, environmentally friendly disinfecting agent. In this study, aqueous chlorine dioxide (ACD) was used to improve the water quality of dental chairs. However, chlorine dioxide is readily released from ACD solutions under open atmosphere conditions. Described herein is a water purification and disinfection system using ACD. The system was designed, fabricated, and integrated into an existing dental chair water system. This system is referred to as an ACD dental chair. Because ClO2 readily degasses from ACD, there needs to be a way to maintain and measure the ACD solution in real time. In our studies, we found that pH and oxidation-reduction potential (ORP) change as a function of chlorine dioxide concentration and are easily controlled and measured. The dosing of the ACD was designed to begin at 800 mV and stop dosing at 810 mV in the ACD dental chair. Through use of this continuous monitoring and automatic dosing system, the water ORP was controlled between 800 and 860 mV. This range is the effective concentration of chlorine dioxide that is without chlorine-like odor and microorganism growth. The ACD dental chair controlled the total bacterial count to <5 CFU/mL and the chlorite concentration was less than 0.0004 mg/L, meeting legal standards of Taiwan, the USA, and China. In addition to the application of ACD in dental chairs, it may also be used in closed water systems for food, cosmetics, beverages, and other industries.

Effect of water quality on the spatial distribution of charophytes in the Peshawar Valley, Khyber Pakhtunkhwa, Pakistan

The presented research was conducted in 2018–2019 in the Peshawar Valley, Pakistan, to study for the first time the effect of water quality on the spatial distribution of charophytes. A total of six taxa of charophytes were found at 41 sites in the Peshawar Valley along the banks of seven rivers, 16 streams and two wetlands: Chara braunii C.C.Gmelin, C. connivens Salzmann ex A. Braun, C. contraria A. Braun ex Kützing, C. globularis Thuiller, C. vulgaris Linnaeus, and Nitellopsis obtusa (Desvaux) J. Groves. Chara vulgaris was the most abundant species, followed by C. globularis, and C. contraria. Water pH, electrical conductivity (EC), total dissolved solids (TDS), salinity and dissolved oxygen (DO) were within the permissible limits for Pakistan, while water temperature, oxidation reduction potential (ORP) and resistivity showed deviations. Canonical Correspondence Analysis (CCA) revealed that DO affected Chara vulgaris, pH and resistivity affected C. braunii, C. connivens and C. globularis, temperature and ORP affected C. contraria and Nitellopsis obtusa. Furthermore, CCA showed that TDS, EC, and salinity had no effect on the spatial distribution of Chara contraria, C. vulgaris and Nitellopsis obtusa. Chara contraria and Nitellopsis obtusa should be protected under VU (Vulnerable) status (IUCN) along with their habitats.

Study on the Prevention and Control of Fe and Mn Pollution by Resistant Mixed Bacteria in Simulated Mining Area

By simulating the mining environment, the potential of the selected mixed bacteria (Pseudomonas putida, Lysinibacillus xylanilyticus, Lysinibacillus macroides, Bacillus simplex, Brevibacillus agri) to control Fe and Mn pollutants in mining environment were explored. The results showed that the selected bacteria could inhibit the release of Fe and Mn from ore into the aquifer, and the inhibition effect on Mn was significantly stronger than that on Fe. At the same time, these processes also have a certain degree of impact on the external environment, including the gradual increase of pH, the gradual decrease of oxidation-reduction potential, and the decrease of dissolved oxygen concentration. The changes of these external environmental factors will once again directly affect the degradation and immobilization of Fe and Mn. The selected mixed bacteria can also enhance the adsorption of free Fe and Mn, improve the adsorption efficiency and capacity of Fe and Mn, and slow down the desorption of Fe and Mn to water.

Study of Physicochemical of Rivers in DKI Jakarta Province

Most of inland water in DKI Jakarta Province are highly polluted caused by the increase in urbanization, industrialization development and reclamation process. This research intend to conduct an initial characterization of the water quality in Jakarta. The survey was conducted in 9 location namely Kali Sunter 1, Kali Sunter 2, Cakung Drain, POM Vyle Pluit, Waduk Pluit, Museum Bahari, WTC Mangga Dua, Mookenvart and Pesanggrahan. Based on the level of salinity, the rivers are categorized into fresh water (Cakung Drain, WTC Mangga Dua, Mookenvart and Pesanggrahan) and brackish water (Kali Sunter 1, Kali Sunter 2, Pluit Village, Waduk Pluit, and Museum Bahari). The physicochemical measurement using Water Quality Checker reported turbidity and Total Dissolved Solid (TDS) concentration were very high at all sampling locations. The Oxidation Reduction Potential (ORP) value can be used to determine the pollution status. Pesanggrahan is the only river with a positive ORP value of 22 mV. It can be said that the pollution level of the Pesanggrahan is very low. The other rivers have a negative ORP value and the largest is in Kali Sunter 2. Serious efforts need to be made in dealing with inland waters pollution located in Jakarta.

Nontuberculous Mycobacteria Prevalence in Bats’ Guano from Caves and Attics of Buildings Studied by Culture and qPCR Examinations

A total of 281 guano samples were collected from caves (N = 181) in eight European countries (Bulgaria, Czech Republic, France, Hungary, Italy, Romania, Slovakia and Slovenia) and attics in the Czech R. (N = 100). The correlation of detection of mycobacteria between Ziehl–Neelsen (ZN) microscopy and culture examination and qPCR was strong. ZN microscopy was positive in guano from caves (58.6%) more than double than positivity in guano from attics (21.0%; p < 0.01). From 89 mycobacterial isolates (73 isolates from cave guano and 16 isolates from attics’ guano), 68 (76.4%) isolates of 19 sp., ssp. and complex were identified as members of three Groups (M. fortuitum, M.chelonae, and M. mucogenicum) and four complexes (M. avium, M. terrae, M.vaccae, and M.smegmatis). A total of 20 isolates (22.5%) belonged to risk group 1 (environmental saprophytes), 48 isolates (53.9%) belonged to risk group 2 (potential pathogens), and none of the isolates belonged to risk group 3 (obligatory pathogens). When comparing bat guano collected from caves and attics, differences (p < 0.01; Mann–Whitney test) were observed for the electrical conductivity, total carbon, total organic, and total inorganic carbon. No difference (p > 0.05; Mann–Whitney test) was found for pH and oxidation-reduction potential parameters.

Nontuberculous Mycobacteria Prevalence in Bats’ Guano from Caves and Attics of Buildings Studied by Culture and qPCR Examinations

A total of 281 guano samples were collected from caves (N = 181) in 8 European countries (Bulgaria, Czech Republic, France, Hungary, Italy, Romania, Slovakia and Slovenia) and attics in the Czech R. (N = 100). The correlation of detection of mycobacteria between Ziehl-Neelsen (ZN) microscopy and culture examination and qPCR was strong. ZN microscopy was positive in guano from caves (58.6%) more than double than positivity in guano from attics (21.0%; P &amp;lt;0.01). From 89 mycobacterial isolates (73 isolates from cave guano and 16 isolates from attics&rsquo; guano) 68 (76.4%) isolates of 19 sp., ssp. and complex were identified as members of 3 Groups (M. fortuitum, M. chelonae, and M. mucogenicum), and 4 Complexes (M. avium, M. terrae, M. vaccae, and M. smegmatis). A total of 20 isolates (22,5%) belonged to risk group 1 (environmental saprophytes), 48 isolates (53.9%) belonged to risk group 2 (potential pathogens), and none of isolates belonged to risk group 3 (obligatory pathogens). When comparing bat guano collected from caves and attics, differences (P&amp;lt;0.01; Mann-Whitney test) were observed for the electrical conductivity, total carbon, total organic and total inorganic carbon. None difference (P&amp;gt; 0.05; Mann-Whitney test) was found for pH and oxidation-reduction potential parameters.

Analyzing changes in a leach solution oxygenation in the process of uranium ore borehole mining

Purpose is to increase uranium content in a PR solution while developing a technique varying oxidation-reduction potential of a leach solution with its oxygenation and identify changes in the oxygenation depending upon sulfuric acid concentration as well as transportation distance of the solution. Methods. A laboratory facility, involving solution tank, pump, Venturi tube, tank to install oxygen analyzer, and a dump tank, has been manufactured under the lab conditions to determine a leach solution oxygenation taking into consideration its delivery rate, sulfuric acid concentration, and temporal preservation of the concentration. Solution flow velocity; the deli-vered solution volume; sulfuric acid concentration; and distance from oxygenation point to a seam changed and varied during the study. Oxygenation was measured with the help of AZ 8403 oximeter; IT-1101 device was used to measure pH value as well as oxidation-reduction potential (ORP). Findings. A technique for a leach solution oxygenation and results of laboratory tests to identify influence of a sulfuric acid as well as transportation distance of a solution on oxygen concentration in the solution have been represented. It has been determined that Venturi tube helps oxygenize a leach solution; in this context, maximum oxygen concentration is achieved if a flow velocity is optimum one. It has been specified that a solution oxygenating depends upon a sulfuric acid concentration decreasing moderately with the increasing distance of the solution transportation. Originality.Following new dependencies have been determined: oxygen concentration in a solution upon a flow velocity and solution volume; and oxygen concentration in a solution upon distance from concentration place and sulfuric acid concentration. Practical implications.A leach solution oxygenation results in the increased oxidation-reduction potential and in the increased content of a useful component in the pregnant solution respectively. The proposed technique is notable for its low capital spending. Moreover, it is integrated easily into the available system being absolutely environmentally friendly.