Inlet Point Research Articles

Removal efficiencies of microplastics of the three largest drinking water treatment plants in Bangladesh

Drinking water treatment plants (DWTPs) are intended to provide safe water to the municipality, typically by treating surface waters from rivers, lakes, and streams. Regrettably, all of these water sources for DWTPs have been reported to be contaminated by microplastics (MPs). Hence, there is an urgent need to investigate the removal efficiencies of MPs from raw waters in the conventional DWTPs anticipating public health concerns. In this experiment, MPs in the raw and treated waters of the three major DWTPs of Bangladesh, having different water treatment processes, were evaluated. The concentrations of MPs in the inlet points of Saidabad Water Treatment Plant phase-1 and 2 (SWTP-1 and SWTP-2), which share a similar water source of the Shitalakshya River, were 25.7 ± 9.8 and 26.01 ± 9.8 items L−1. The third plant, Padma Water Treatment Plant (PWTP) utilizes water from the Padma River and had an initial MP concentration of 6.2 ± 1.6 items L−1. The studied DWTPs, with their existing treatment processes, were found to reduce the MP loads substantially. The final MP concentrations in treated waters of SWTP-1, SWTP-2, and PWTP were 0.3 ± 0.03, 0.4 ± 0.01, and 0.05 ± 0.02 items L−1 with the removal efficiencies of 98.8, 98.5, and 99.2 %, respectively. The considered size range of MP was 20 μm to <5000. Fragments and fibers were the two predominant MP shapes. In terms of polymer, the MPs were polypropylene (PP, 48 %), polyethylene (PE, 35 %), polyethylene terephthalate (PET, 11 %), and polystyrene (PS, 6 %). The field emission scanning electron microscopy-energy dispersive X-ray spectroscopy (FESEM-EDX) revealed the fractured and rough surfaces of the remaining MPs, which were also found to be contaminated with heavy metals, like lead (Pb), cadmium (Cd), chromium (Cr), arsenic (As), copper (Cu), and zinc (Zn). Hence, additional initiatives are required to remove the residual MPs from the treated waters to safeguard the city dwellers from potential hazards.

Influence of Oslo crystallizer structure characteristics on crystallization process

AbstractThe liquid–solid multiphase flow in Oslo crystallizer was simulated by computational fluid dynamics (CFD) and described by Euler–Euler model and k‐ε turbulence model. The velocity field and solid phase concentration field in Oslo crystallizer with different structural elements were systematically studied. The results show that, within the range of 0–82.5°, the fluid velocity and axial mixing in the evaporation chamber are significantly affected by the inlet pipe structure, and the length of the central downcomer also has distinct impact on the crystal classification ability of the crystallizer. As the angle between the axis of the inlet pipe and the tangent line at the inlet point increases, the tangential velocity in the evaporation chamber decreases, the axial velocity near the wall increases, and the volume fraction of solid particles decreases. As the length of the central downcomer increases, the position of the vortex center gradually goes up and moves towards the wall. In order to obtain high‐quality products and extend the continuous operation cycle of the device, the angle between the axis of the inlet pipe and the tangent line at the inlet point should be 60–75°, and the distance between the central downcomer and the bottom of the crystallizer should be .8 m.

Using a compact unit for nitrification and denitrification processes followed by activated carbon filtration to remove total nitrogen from ammonium-contaminated groundwater

Abstract The current study aims to evaluate the removal of ammonium-nitrogen (NH4+-N), generated nitrite (NH2−-N), and nitrate (NH3−-N) from groundwater using a compact unit for nitrification and denitrification processes that consist of a dripping nitrification reactor followed by a denitrification biofilter filled with treated cotton. Moreover, activated carbon filtration was applied as a post-treatment technique to remove the released total organic carbon (TOC) after the denitrification biofilter. The raw groundwater had an average NH4+-N concentration of 29.8 mg/L. To complete the analytical measurements, samples were taken from the compact unit's inlet, outlet, and sampling points for nitrification and denitrification, as well as the activated carbon filter. The obtained results indicated that the nitrification efficiency reached 98.81%, while the denitrification efficiency reached 95.98%. Moreover, the removal rate of total nitrogen ranged between 122.5 and 147 mg/d. On the other hand, the denitrification process utilizing cotton media resulted in a considerable increase in the outlet TOC concentrations, which ranged from 52.1 to 74.2 mg/L. The activated carbon filtration was applied to vanish the released TOC from the denitrification process after 10 days of operation.

Removal of Manganese and Iron from Groundwater by using Chlorination and Rapid Sand Filtration: A Case Study

The average groundwater extraction from Murunkan well field, Mannar, is around 3.4 MCM/year, and it was triggered by extensive development projects and resettlements that took place in the last decade. Manganese and Iron variations in Murunkan groundwater reported during some periods created various operational and aesthetic issues in the potable water supply. This study is focused on treating iron and manganese in groundwater using chlorination and Rapid Sand Filtration (RSF) techniques. Pebble layers, height of 205 mm with the particle sizes ranging from 2-25 mm, were filled at the bottom of RSF model filter. Filter media, height of 700 mm with 0.45 mm effective size (D10) and a uniformity coefficient (Cu) of 1.33, was placed above the pebble layers. The filter was operated continuously for 15 days, and influent and effluent water samples were collected from 15 trials. Filter backwashing was performed after every two trials to maintain a consistent filtration rate. Raw water pH values ranged from 6.74 – 7.48. Chlorine solution (1.08-1.26 ppm) was added at the inlet point, and a 2.88 m water column was maintained, allowing adequate mixing and oxidation time. The results revealed that average removals of iron and manganese as 60% and 73%, respectively, while maximum removals of 93% and 91% were observed for iron and manganese, respectively.

Anatomical study of the technique of the axis laminar screws and development of guide

PurposeTo develop a bidirectional slide guide to assist screw placement in the axial lamina and to preliminarily discuss the accuracy and feasibility of auxiliary screw placement.MethodsCT data from 40 randomly selected patients were imported into the software for modelling, and cross-pinning was used to simulate pinning. According to the different crossing methods of the upper and lower laminar screws, they are divided into two groups. In the software, the position of the needlepoint of each screw is accurately measured, and the needle point is kept unchanged to simulate the movable range of the screw tail under the condition that the body does not penetrate the cortical bone. The data were compared by grouping and gender. Finally, the guide was designed by combining the screw exit point and fine adjustment angle data of all patients with the centripetal principle of the slide rail.ResultsThe needle exit data L1/L2/L3/L4 were 6.44 ± 0.52 mm, 7.05 ± 0.48 mm, 3.55 ± 0.75 mm and 5.09 ± 0.74 mm, respectively, and the fine adjustment angle of the slide rail was 10.51° ± 0.87°. There was no significant difference between the two groups or between men and women (p > 0.05).ConclusionIn this experiment, using the data obtained from the simulation of screw insertion, a two-way slide guide was designed to assist the insertion of axial laminar screws. The guide locks the screw outlet point to position and guides the screw inlet point, which improves the accuracy and safety of screw placement.

Visual Assessment of Factors Affecting Reverse Pressure Gradients in Liners Using a Simulated Milking Device

Highlights In a simulated milking device, liner internal diameter, pulsation setting, and vent location all affect backflow. Junction point internal diameter affects backflow more than other factors. Vent location has no effect on backflow if the liner internal diameter is large. Backflow is strong with simultaneous pulsation, regardless of other factors. Abstract. The backflow of milk resulting from reverse pressure gradients in liners can cause mastitis. In this study, we hypothesized that liner internal diameter, vent location, and pulsation setting can induce backflow. We therefore attempted to clarify the mechanism of backflow using a flow simulated device. We visually analyzed the effects on backflow of the liner junction point (JP) (i.e., the border from the liner to the short milk tube), the liner inlet point (IP) (i.e., a distance of 63 mm from the end of the short milk tube), vent location, and pulsation setting, using high-speed video recordings of water flow in clear silicone liners at seven flow rates (1.0, 1.5, 2.0, 2.5, 3.0, 3.5, and 4.0 kg min-1/quarter). The actual flow rate was approximately half of the flow meter set value due to the effect of the pulsation closing phase (C+D phase) on quarter level. The results showed that the degree of backflow in liners increased considerably with an increase in flow rate and a decrease in liner internal diameter. The degree of backflow was affected considerably more by JP internal diameter than by IP internal diameter, pulsation setting, or vent location. The degree of backflow was not affected significantly by short milk tube vents and mouthpiece vents when JP internal diameter was larger. However, the degree of backflow was very strong when simultaneous pulsation was used, even at low flow rates. The findings showed that the JP internal diameter should be &amp;gt;13.0 mm, IP internal diameter should be &amp;gt;11.0 mm, the pulsation rate should be 60 pulses/min, and the pulsation ratio should be 60:40 when the alternative pulsation setting is used. This information might be useful for preventing intramammary gland infection. Keywords: Liner internal diameter, Pulsation setting, Reverse pressure gradients, Simulated milking device, Vent location.

Performing in spite of starvation: How Saccharomyces cerevisiae maintains robust growth when facing famine zones in industrial bioreactors.

In fed-batch operated industrial bioreactors, glucose-limited feeding is commonly applied for optimal control of cell growth and product formation. Still, microbial cells such as yeasts and bacteria are frequently exposed to glucose starvation conditions in poorly mixed zones or far away from the feedstock inlet point. Despite its commonness, studies mimicking related stimuli are still underrepresented in scale-up/scale-down considerations. This may surprise as the transition from glucose limitation to starvation has the potential to provoke regulatory responses with negative consequences for production performance. In order to shed more light, we performed gene-expression analysis of Saccharomyces cerevisiae grown in intermittently fed chemostat cultures to study the effect of limitation-starvation transitions. The resulting glucose concentration gradient was representative for the commercial scale and compelled cells to tolerate about 76 s with sub-optimal substrate supply. Special attention was paid to the adaptation status of the population by discriminating between first time and repeated entry into the starvation regime. Unprepared cells reacted with a transiently reduced growth rate governed by the general stress response. Yeasts adapted to the dynamic environment by increasing internal growth capacities at the cost of rising maintenance demands by 2.7%. Evidence was found that multiple protein kinase A (PKA) and Snf1-mediated regulatory circuits were initiated and ramped down still keeping the cells in an adapted trade-off between growth optimization and down-regulation of stress response. From this finding, primary engineering guidelines are deduced to optimize both the production host's genetic background and the design of scale-down experiments.

Microcosmic plant and fungi synergism-based filter to remediate the pollutants from industrial wastewater

Plants release compounds that signal microbes to engage in interactions. This interaction results in increased germination efficiency and root elongation, resulting in improved pollutant breakdown in both the rhizosphere and the phyllosphere. Most plants are symbiotic with fungi and these fungi play important roles in the structure, function, and health of plant communities. This study focuses on the potential of Syngonium podophyllum and Trichoderma harzianum fungi synergism to uptake the pollutants from the pretreated industrial wastewater collected from CETP common inlet point characterized by high COD (401 mg/l), BOD (159 mg/l), Nitrate (10.6 mg/l), and Lead (0.3 mg/l). Three setups S1 (Syngonium with Industrial wastewater water), S2 (Immobilized Trichoderma with Industrial wastewater), and S3 (Syngonium with Trichoderma & Industrial wastewater) were installed to treat pretreated industrial wastewater before entering CETP (Common effluent treatment plant). Compared to other treatments, the S3 setup was found more efficient to reduce the pollutants COD, BOD, NO3-N, and Pb by 82 %, 75.4 %, 70.7 %, and 80 % respectively in 6 days while S1 could reduce only 59.6 % COD, 63.1 % BOD, 42.4 % Nitrate and 80 % Lead and S2 setup reduced the COD, BOD, Nitrate, and Lead by 55.1 %, 40.8 % 33.9 % and 63.3 % respectively. The BCF (Bio Concentration Factor) and TF (Translocation Factor) of Syngonium were also improved in setup S3 (0.66 and 0.04 respectively) as compared to treatment setups S1 and S2. Based on the findings, it is feasible to conclude that using plant-immobilized fungal cell synergism for increased remediation of pollutants from wastewater is an environmentally benign and cost-effective strategy.

Odor emission assessment of different WWTPs with Extended Aeration Activated Sludge and Rotating Biological Contactor technologies in the province of Cordoba (Spain)

In this study, five urban WWTPs (Wastewater Treatment Plant) with different biological treatment (Extended Aeration Activated Sludge – EAAS; Rotating Biological Contactor – RBC), wastewater type (Urban; Industrial) and size, were jointly evaluated. The aim was twofold: (1) to analyze and compare their odor emissions, and (2) to identify the main causes of its generation from the relationships between physico-chemical, respirometric and olfactometric variables. The results showed that facilities with EAAS technology were more efficient than RBC, with elimination yields of organic matter higher than 90%. In olfactometric terms, sludge managements facilities (SMFs) were found to be the critical odor source in all WWTPs compared to the Inlet point (I) or Post primary treatment (PP), and for seasonal periods with ambient temperature higher than 25 °C. Moreover, the global odor emissions quantified in all SMFs revealed that facilities with EAAS (C-WWTP, V-WWTP and Z-WWTP) had a lower odor contribution (19,345, 14,800 and 11,029 ouE/s·m2, respectively) than for those with RBC technology (P-WWTP and NC-WWTP) which accounted for 19,747 ouE/s·m2 and 80,061 ouE/s·m2, respectively. In addition, chemometric analysis helped to find groupings and differences between the WWTPs considering the wastewater (71.27% of total variance explained) and sludge management (64.52% of total variance explained) lines independently. Finally, odor emissions were adequately predicted from the physico-chemical and respirometric variables in the wastewater (r2 = 0.8738) and sludge (r2 = 0.9373) lines, being pH, volatile acidity and temperature (wastewater line), and pH, moisture, temperature, SOUR (Specific Oxygen Uptake Rate) and OD20 (Cumulative Oxygen Demand at 20 h) (sludge line) the most influential variables.

Clinical advantages and neuroprotective effects of monitor guided fang's capillary fascia preservation right RLN dissection technique.

ObjectiveTo investigate the feasibility and advantages of Fang’s capillary fascia preservation right recurrent laryngeal nerve (RLN) dissection technique (F-R-RLN dissection) with preservation of the capillary network and fascia between the RLN and common carotid artery for greater neuroprotective efficiency compared with traditional techniques.MethodsWe retrospectively analyzed 102 patients with papillary thyroid carcinoma undergoing right level VI lymph node dissection in our department from March 2021 to January 2022. Sixty patients underwent F-R-RLN dissection (the experimental group) and 42 patients underwent standard dissection (the control group). The intraoperative electrical signal amplitude ratios of the RLN, the number of dissected lymph nodes, and the preservation rates of the parathyroid glands were recorded and compared between the two groups.ResultsThe electrical signal amplitude ratio of the lower neck part point of the RLN to the upper laryngeal inlet point in the experimental group was significantly lower than the ratio in the control group (p = 0.006, Z-score = -2.726). One patient suffered transient RLN paralysis in both groups, but this resolved within 1 month after operation. There were no significant differences between the two groups in terms of the number of level VIa or level VIb lymph nodes dissected, nor in the rate of preservation of the parathyroid glands.ConclusionsF-R-RLN dissection is a thorough dissection technique that is effective at preventing an electrical signal amplitude decrease in the RLN, and at preventing RLN paralysis by preserving its blood supply.

Removal and kinetics of basic pollutants in serially constructed wetlands

In this research, the spatial distribution and kinetic coefficient of basic pollutants in the artificial wetlands (CW) of the DACBiol-UJAT wastewater treatment plant were evaluated. It consists of a sump-settler and two identical modules with HA in series 8.3 m long, 2.5 m wide and 0.5 m long. In both trains, the first HA is subsurface flow (SSFCW) with Pontederia cordata (tule) species, the second HA is free flow (FFCW) with Thalia geniculata (popal) and the last HAFL with Sagittaria lancifolia (dovetail). The characterization of the support medium, water quality (inlet, outlet and internal points), modeling of the spatial distribution and kinetics of color degradation, turbidity and COD were carried out. Both trains operated with a 3-day HRT with a Qmed of 8.9 ± 3.4 m3/day. The quality of the inlet water of train 1 presents an average turbidity of 72.3 UTN, color of 1340.0 UC and COD with 373 mg/L, likewise at the entrance of train 2 the average turbidity is 69.6 UTN, color of 1,190.3 UC and COD with 373 mg/L. The degradation kinetic constant was estimated in train 1 at -0.52 days-1 for turbidity, -0.32 days-1 for color and -0.58 days-1 for COD, for train 2 of -0.47 days-1 for turbidity, -0.24 days-1 for color and -0.49 days-1 for COD. The removal efficiency for turbidity in train 1 was 65.6% and train 2 was 67.9%, for the apparent color in train 1 it was 48.8% and train 2 was 58.3% and in COD in train 1 it was 81% and for train 2 of 76%. The maximum permissible COD limit according to PROY-NOM-001-SEMARNAT-2017 is met, which is 150 mg/L.

EFEKTIVITAS BIOFILTER DALAM MEREDUKSI POLUTAN PADA AIR LIMBAH RUMAH SAKIT DI KOTA PALU

The existence of pollutants in hospital wastewater has the potential to pollute the environment, so they are obliged to process the liquid waste before it is released into nature. To ensure that wastewater is feasible to be discharged into the environment, it is necessary to treat it through a Wastewater Treatment Plant, one of which is the aerobic anaerobic biofilter method. This study aims to determine the effectiveness of anaerobic aerobic biofilter in reducing pollutants in wastewater in terms of the physical, chemical and biological parameters. This study uses a quasi experiment with sampling technique composite sample by time. Color and odor parameters were checked organoleptically, while pH and temperature were measured insitu using a multifunctional portable device. Parameters of BOD, COD, NH3, TSS and MPN Coliform analyzed in the laboratory for quality assurance of each sample is checked duplo. The study results of the Anutapura Hospital's wastewater treatment are still a slighly cloudy but odorless, this is not in accordance with the wastewater quality standards in the Minister of Environment Regulation Number 5 of 2014, on the contrary at Madani Hospital the color and odor parameters have met the quality standards. The values of temperature, pH, BOD, COD and TSS have met the quality standard requirements at both hospitals even from the inlet point. this is because it is good of preliminary treatment to be carried out before the wastewater flows into the biofilter. While the value of TSS and MPN coliform, at the inlet and outlet point has exceeded the quality standard. The effectiveness percentage of BOD reduction in Anutapura Hospital and Madani Hospital is 70.2% and 47.6%, for COD reduction is 53.4% and 27%, NH3 reduction 95.9% and 69.4% and TSS reduction is 65.2% and 70.2%. Based the data, concluded that increasing the percentage of biofilter effectiveness is still necessary.&#x0D; Keywords: anaerobic, aerobic, biofilter, WWTP

Experimental Study on Manned/Unmanned Thermal Environment in Radar Electronic Shelter Based on Different Air Supply Conditions

Studies on the thermal environment of the electronic radar shelter have been mainly focused on the simulation of the unmanned thermal environment, and there have been few studies on experiments in the thermal environment. Additionally, a comparative study of the experimental results from manned and unmanned shelters has been missing. In this paper, we experimented in thermal environments of manned/unmanned shelter under different air supply conditions. The experiment was divided into cooled, ventilated, and heated trials analyzing three aspects: (1) The average temperature distributions of walls, air inlet points, air outlet points, and surfaces were measured over time under different conditions in an unmanned shelter. The temperature distribution curve was fitted into the function. (2) Based on different working conditions, the temperature distribution experiments were carried out in three different areas for subjects wearing short or long clothing respectively. (3) The wind speed was measured at each measuring point in the air supply pipeline under different working conditions. The wind speed distribution was detected on the setting surfaces. The experimental results show that: (1) The air does not gradually tend to steady state with the time, and under different conditions, the air temperature obviously differs. (2) The clothing selection, air supply conditions, and locations of measuring points have significant influences on human body temperature distribution and left–right difference. (3) The mixing of the thermal plume caused by the vertical temperature difference of the human body and the jet generated by the mechanical air supply will reduce the wind speed of the airflow in the cabin, the adsorption of the jet to the bulkhead, and the stability of the airflow. The experimental data can provide the initial and boundary conditions for the simulation of the shelter. The results can provide a reference for the study of fluid control methods, the setting of thermal boundary conditions, and the simulation of the influence of thermal plumes on the airflow distribution. The experimental study in this paper has filled in the blanks regarding experimental study in electronic radar shelters. It has important research value and practical significance.

Assessment of Water Quality Status of Cengklik Reservoir due to Eutrophication

Cengklik Reservoir is one of the water sources that has the main function for irrigation and aquaculture. Based on satellite imagery of the Cengklik Reservoir 2000-2020, about 30% of the waters of the Cengklik Reservoir have been covered by water hyacinth. The use of chemical fertilizers, pesticides and fish farming activities using floating net cages are the main factors causing eutrophication. Therefore, the purpose of this study was to analyze the water quality of the Cengklik Reservoir at the inlet and outlet points of the Cengklik Reservoir and then determine the level of pollution using the Pollution Index (PI) method. The water quality parameters tested were temperature, pH, TSS, DO, BOD, COD, TSS, Total-P, and Total N. Based on the results of the PI analysis, the water quality of Cengklik Reservoir was categorized as lightly polluted and does not exceed the quality standard value of Government Regulation No. 22 years 2021 other than phosphate. Phosphate parameter values at inflow 1, inflow 2, inflow 3 and outflow locations are 0.166 mg/L; 0.166 mg/L; 0.723 mg/L and 0.166 mg/L which are estimates of the cause of eutrophication in the Cengklik Reservoir.

Automatic Rescheduling of Generator for Rotor Speed Regulation by KRASOVSKII’s Theorem

Emergency control of the power system is performed via generator rescheduling or load shedding depending upon the availability of generation and demand. This paper presents a generator rescheduling method based on Krasovskii&#x2019;s theorem for enhancing rotor speed regulation during multiple contingency conditions. The speed governor in automatic generation control (AGC) and automatic voltage regulator (AVR) are indispensable components of the control mechanism for deploying any control scheme. Contingencies may lead the security state of the power system towards a preventive, emergency, and restorative state. Generally, there is a violation of equality constraints of active and reactive power in the corrective security state. However, in this paper, the corrective security state considers a significant imbalance in active power with a generation capacity always greater than load. For rotor angle stability, active power delivery by the generator met the demands, whilst the turbine and automatic speed governor together balance it by changing the set point of the turbine inlet. This paper investigates the rotor stability by triggering a new set point by the rescheduling of the generator. The strategy proposed encompasses the broad domain of active power imbalance using Krasovskii&#x2019;s theorem, which is an extensive form of the Lyapunov stability theorem for the nonlinear multivariable autonomous system. The proposed control scheme is deployed on an IEEE-10 machine 39-bus system for validation and feasibility detection. It is found that the proposed scheme is more accurate than the conventional turbine automatic speed governor close loop system. Moreover, there is turbine power-saving up to 400 MW. In addition, the rotor attains steady-state speed quicker up to 5-10 sec and attains synchronous speed in all the cases considered, i.e., single load outage; multiple load outage; area outage; and load increment. The MATLAB&#x00AE; and the CVX platform are used to validate the proposed concept.

Experimental study on the thermal performance of a flat plate solar water collector with a bifunctional flow insert

A flat plate solar water collector is a simple solar energy conversion system for hot water production. In this experimental work, the effect of bifunctional rectangular cut flow deviator longitudinal flow inserts with a tilt angle of 30° fixed inside the absorber tube is studied with different water flow rates (0.0083, 0.0167, and 0.025 kg/s). The maximum instantaneous efficiency obtained is 72.93% at 0.025 kg/s, which is 23.6% higher than that of the conventional collector, and a lower mass flow rate results in better exergy efficiency of 3.3% at 0.0083 kg/s. The maximum instantaneous efficiency for a modified collector is observed when the outlet water temperature of 56.7 °C and the proposed flow inserts result in a maximum temperature difference of 10.5 °C between the water inlet and outlet points. The flow inserts serve as a turbulence promoter to enhance the heat transfer coefficient and the heat absorption rate of a conventional collector. The significant contribution of the flow inserts towards increasing the instantaneous efficiency of the collector confirms the bifunctionality with minimum pressure drop and pumping power. The enviro-economic analysis ensures a clean production, and solar collectors with passive inserts provide a lower payback period due to higher thermal energy output. The proposed collector's annual CO₂ mitigation and carbon credit are higher than the conventional collector, and such collectors are feasible for commercialization.

Comparison of Heat Transfer rates for Water and Ethylene Glycol mixtures for Diesel engine exhaust gas heat recovery using Shell and Tube Heat Exchanger.

Most of the researchers have claimed that high compression engines (diesel engines) are performing slightly above of 1/3rd of their potential and remaining heat energy is wasted in the form of exhaust gas. Efforts are going on to improve the design of these engines and investigations are being carried out to recover this waste energy from exhaust gases and utilize for different applications.In the present work, initially water is used as a heat exchange medium for three different loads on diesel engine viz., 50%, 60% and 70%, which extracts heat energy to evaluate the exhaust heat attainable from exhaust gases of the engine. The exhaust gas is passed through the tube side of the heat exchanger which is obtained from an exhaust manifold of a four stroke single cylinder diesel engine. Water is passed through the shell side of the shell and tube heat exchanger. Later this work is repeated for two different cooling medium i.e. water-ethylene glycol mixtures with 25% and 50%. The results are compared for 60% engine load conditions. The counter flow type heat exchanger arrangement is considered for the analysis. The temperatures were recorded for hot gases and cold medium at inlet and outlet points of the shell side and tube side flow. Heat calculations are carried out for each combination and detailed in the result–discussion and conclusion chapter. The objective of this work is to assess the exhaust gas heat recovery capacity using the ethylene glycol-water mixture and come out with a mixture for higher heat recovery capacity. This work is undertaken with segmental baffle heat exchanger of zero degree inclination. Also the work is repeated for inclined baffle heat exchangers of 10-degree and 20-degree baffle inclination to assess the effectiveness of liquid in recovering the heat from exhaust gases. It is observed that the water and Ethylene glycol mixtures have performed satisfactorily in all three baffle setups showing only 1.5% - 2.0% less heat recovery when compared with only water.

MONITORING OF 2-METHYLISOBORNEOL AND GEOSMINE IN A CONSTRUCTED LAKE TO PUBLIC CATCHMENT IN SOUTHERN BRAZIL

People that consumed treated water from Dourado Lake, Santa Cruz do Sul, RS, Brazil perceived alterations in its taste and odor. Based on this, we focused our study on the monitoring of 2-MIB and GSM in samples collected from Dourado Lake, using solid-phase microextraction (SPME) coupled to gas chromatography/mass spectrometry (GC/MS). The monitoring was done by performing exploratory evaluations at several points on the lake during the summers of 2017 and 2018 and in all seasons of 2019, considering points of water in an inlet and an outlet of the lake. At the inlet point, the average concentration of GSM was 7.56 ± 1.94 ng L-1 and that of 2-MIB was 33.09 ± 6.89 ng L-1. However, for the outlet point, the average concentrations of GSM and 2-MIB were 10.62 ± 2.51 ng L-1 and 28.72 ± 10.47 ng L-1, respectively. In all cases, the presence of GSM and 2-MIB was perceptible by the people consuming the water (during all seasons), showing the need for correct management of water resources.

Rational design of the inlet configuration of flow systems for enhanced mixing

High mass transfer rate is a key advantage of microreactors however, under their characteristic laminar flow, it is dominated by slow diffusion rather than fast convection. In this paper, we demonstrate how the configuration of the inlet, i.e. mixers, can promote different flow patterns to greatly enhance mixing efficiency downstream. A systematic evaluation and comparison of different widely adopted mixers as well as advanced designs is presented using a combination of computational fluid dynamics (CFD) and backward particle tracking to accurately calculate diffusion, in the absence of numerical diffusion (false diffusion). In the method, the convection contributed concentration profile is obtained by tracking sampling points from a cross-sectional plane to the inlet point, and diffusion is estimated subsequently. In conventional T- and Y-mixers, the shape of channel, circular or square, is key with only the latter promoting engulfment flow. In cyclone mixers, the resulting average inlet velocity, independent of Reynolds number or geometry, is the dominating design parameter to predict mixing efficiency. This work will serve as a guideline for the design of efficient flow systems with predicted mixing as a way of maximising selectivity and product quality.

유수율 제고를 위한 블록시스템 고립구축의 적용

In this study, the definition and standards of the block system, and the block isolation confirmation method were reviewed to establish an effective block system. The study target area was selected and a block system construction plan was established. First, for small blocks that cannot find unused pipelines connecting between small blocks, a method of operating small blocks by partially changing the small block boundaries planned in the drawing to match the site conditions can also be an effective method for block system management. The second is to secure water quality stability through flushing. Blocking the flow and changing the flow direction by operating the valve to confirm the small block isolation is causing red water and pollutants. First of all, it is necessary to examine the method of discharging the accumulated pollutants and red water in the pipe. Finally, Before the block isolation confirmation, the boundaries were not divided by drainage or unit area, and the drainage amount could not be analyzed because flow measurement facilities by small block were not equipped. However, after the block isolation was completed, it was possible to calculate the flow rate according to each small block by installing a flow meter at the inlet point. As a result of measuring the flow rate for each small block according to the block isolation confirmation, the SJ-3 small block had the highest average flow rate with 88.9 %, and the SJ-2 small block had the lowest average flow rate with 66.2 %. In addition, it is necessary to subdivide the water supply area for small blocks with low flow rate. It is judged that effective pipe network management will be possible if a small flow rate monitoring system is installed at the inlet point of the subdivided water supply area.