The Use of Amine Reclaimer Wastes as a NOx Reduction Agent

AbstractAmine reclaimer wastes (ARW) generated in carbon capture and sequestration (CCS) is categorized as a hazardous waste which needs proper disposal. The proposal described in this paper can bring about a multi-effective solution to the problem of CCS waste handling. Both the pilot scale and the full scale experimental trials carried out in this study using ARW and pure monoethanolamine (MEA) confirmed the possibility of utilizing ARW as a potential reagent for the selective non-catalytic reduction (SNCR) of NOx in combustion flue gases. Even though the effectiveness of ARW is lower than that of aqueous ammonia, i.e. the most common SNCR chemical reagent used in industry (above 60% NOx reduction efficiency), ARW is nonetheless shown to possess valuable SNCR qualities (at least 20% NOx reduction efficiency) considering its availability as a waste product which has to be safely disposed. A series of thermo-gravimetric analyses provided important information on vaporization characteristics of amine reclaimer bottom wastes. The proposed methodology can lead to simultaneous energy and material resource recovery while primarily solving two environmental pollution problems, i.e. toxic ARW wastes generated in CCS, and emission of NOx a class of highly active greenhouse gases

Investigation of Spatial Distribution Patterns of Environmental Toxicants in Major Reservoirs, Anuradhapura, Sri Lanka

Reservoirs facilitate all requirements of water and act as sinks for toxicants in catchment areas. Those toxicants which are carried out by runoff can be accumulated in bottom sediments and can be released into adjacent water columns with environmental changes. Long term exposure to environmental toxicants in those waters will result adverse health impacts such as chronic kidney failures. Therefore, this study was carried out to investigate the distribution of environmental toxicants; Cadmium (Cd), Lead (Pb), Arsenic (As), Calcium (Ca) and Magnesium (Mg) in Kalawewa and Tissawewa in Anuradhapura district. Fifteen water samples were collected from each reservoir and Cd, Pb, As, Ca and Mg concentrations were analysed by inductively coupled plasma mass spectrometry (ICP-MS). Total hardnessvalues were calculated based on Ca and Mg contents for each sample. Analysed heavy metals and total hardness values were interpolated using ArcMap 10.2.2 software and the contribution of Ca and Mg levels to the hardness were determined. Cd concentrations were ranged from 0.00001 μg/L to 0.04593 μg/L and from 0.00001 μg/L to 0.16246 μg/L in Kalawewa and Tissawewa respectively. Pb concentrations of Kalawewa and Tissawewa ranged from 0.21548 μg/L to 1.77810 μg/L and from 0.00164 μg/L to 18.07452 μg/L respectively. According to the results, As content of Kalawewa ranged from 0.20183 μg/L to 2.70808 μg/L while As content of Tissawewa ranged from 0.00321 μg/L to 3.14488 μg/L. All most all of the sample values for total hardness (TH) were exceeding SLS standards, (250 mg/L). Mg was the major affected factor to the hardness. The highest TH of Kalawewa was 1040 mg/L and the lowest was 396 mg/L. The highest and the lowest TH for Tissawewa were 440 mg/L and 147 mg/L respectively. Based on results, nephrotoxic heavy metal concentrations were higher in centers of the particular water bodies than shallow water columns but not exceeding SLS standards. Usage of proper filtration methods when utilising those water for drinking purposes can be recommended.Keywords: Environmental toxicants, Hardness, Reservoirs, Spatial distributio

Effects of operating conditions on electrodialytic concentration of silver from photo-processing effluents

Electrodialysis is now recognized as a cleaner technology for reclaiming waste chemical solutions including industrial effluents contaminated with heavy metals. Compared with the conventional separation methods (chemical precipitation, filtration, evaporation, electrolysis, etc.), electrodialysis offers remarkable advantages such as less area requirement, ability to incorporate into the production process itself, avoidance of the generation of hazardous chemical sludge and many more. In this study, Electrodialytic recovery of Silver (Ag) from photo-processing effluents was investigated with the aim of understanding the possible effects of various operating conditions on the process. In this study a laboratory fabricated four-membrane, five-compartment, Electrodialysis cell was used with the cationic and anionic selective ion exchange membranes Asahi Kasei K501SB and A501SB, respectively, which are originally used for seawater desalination. The removal efficiency of Ag+ at different current densities was studied, using synthetically prepared metal ion solutions and actual industrial effluents containing Silver (photo processing effluents). Time dependent sampling was done and analyzed with a flame atomic absorption spectrophotometer (GBC 932). According to the experimental results, very significant removal efficiencies were observed in the range of current densities studied. At low current densities of 2 and 4 mNcm2, removal percentages observed were 36 and 53.5, respectively. However at high current densities of 8 and 10 ma/cm", removal percentages increased up to 85 and 96 respectively (for an initial feed concentration of 1000 mg/L). However at those high current densities, ion exchange membranes were found to be damaged due to high heat dissipation. It was also noticed that at low concentrations of feed solution (i.e. 300 and 100 mg/L), the removal efficiencies were reduced remarkably. Considering these results Electrodialysis with the aid of desalination ion exchange membranes could be recognized as an efficient and locally made sustainable technology for treating silver containing effluents having a sufficiently high contamination level, while reclaiming the metal silver for reuse. However the necessity of a final smoothing treatment stage such as metal replacement, ion exchange or adsorption is stressed to obtain higher quality water. Few experimental trials on Electrowinning were also conducted at a single electrical potential (5V), in order to compare the power consumption of the two processes. Results revealed that the power consumption for electrodialysis is comparatively lower than electrowinning (i.e. by only considering the power consumption of the reactor, without accessories). Necessity of the construction of pilot scale reactors is recognized for a full economical review of the two process schemes. On the other hand experiments must be carried out on the synthesis of ion exchange membranes having good permselectivity towards multivalent cations, so that the Electrodialysis process could be applicable on treating other industrial effluents contaminated with multivalent metal cations

Spatial Distribution of Nephrotoxic Heavy Metals in Chronic Kidney Disease of unknown Prevalence Areas via Water Analysis, Sri Lanka

Chronic Kidney Disease of unknown etiology (CKDu) occur due to permanent functional damage of nephrons. Recent research findings explore that Cadmium (Cd), Arsenic (As) and Lead (Pb) can be the most causative nephrotoxic heavy metals due to unavoidable introduction and exposure with the usage of synthetic agrochemicals in intensive agriculture. Present study attempted to determine the spatial distribution of nephrotoxic heavy metals in drinking water, Ambagaswewa GN division, Polonnaruwa, Sri Lanka. 30 drinking water samples were collected from drinking water wells in both dry (Mach, 2019) and wet (November, 2018) seasons and were analysed using Inductively Coupled Plasma mass spectrometry. An analytical framework was developed by Inverse Distance Weighted and Spatial Autocorrelation tools in ArcMap 10.2.2 software to interpolate the spatial distribution of toxicants. According, to the results for the dry season, Cd concentration was ranged between 0.0001 ppb and 0.6524 ppb with an average of 0.1865±0.0967 ppb. The average As content was 0.2992±0.1989 ppb and ranged between 0.001 ppb and 1.6279 ppb while Pb concentration changes from 0.0072 ppb to 6.0601 with an average of 1.3013±0.9845 ppb. According to the Moran’s index (MI) value resulted from spatial auto correlation, Cd (MI=0.1807) and Pb (MI=0.1969) distributions showed clustered patterns especially in the paddy field areas and As showed a random pattern (MI=-0.0439). Pb content in dry season was significantly higher than the wet season (p=0.05). The results conclude that though the concentrations of analysed toxicants were not exceeding the Sri Lankan drinking water quality standards, the people in particular area at a risk with long-term exposure to contaminated drinking water with nephrotoxic heavy metals. Innovative Integrated agricultural systems with minimum usage of synthetic agrochemicals and affordable filtration techniques should implement to reduce further impacts.Keywords: Nephrotoxic, Heavy metals, Interpolate, Autocorrelation, Integrate

Effect of loading density on quality of dried teas in fluidized bed drying

Loading density is a critical parameter that affects the drying behaviour of teas in a fluidized bed dryer and hence the final product quality. During fermentation process, polyphenols available in teas are converted into theaflavin (TF) and thearubigin (TR). However, the final percentages of TF and TR in teas are determined by the post fermentation reactions which take place within the first few minutes of drying. Effect of high loading densities on quality of dried teas was examined for 27, 29 and 31 kg/m2 against the control of 25kg/m2 using orthodox broken type teas. Quality parameters mainly TF%, TR% and tea tasters score were analysed. An increase in both TF% and TROT ratio was observed in teas dried at higher loading densities but the difference from the control sample was not statistically significant at p=0.05. However, professional tea tasters gave higher scores for overall quality of teas dried at higher loading densities based on infused leaf appearance, liquor colour, liquor strength and liquor quality. Results suggest that loading densities may be increased even up to 31 kg/m2 with a marginal improvement to the overall quality of orthodox broken type teas