Agricultural Engineering Research Center

Taoyuan, Taiwan

Agricultural Engineering Research Center

Taoyuan, Taiwan
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Chang H.-H.,National Taiwan University | Chang H.-H.,Agricultural Engineering Research Center | Cheng T.-J.,National Taiwan University | Huang C.-P.,University of Delaware | Wang G.-S.,National Taiwan University
Science of the Total Environment | Year: 2017

This study characterized the fate of nano-TiO2 in both powder (TiO2(P)) and suspension (TiO2(S)) forms in simulated drinking water treatments. Nano-TiO2 solutions of 0.1, 1.0, and 10 mg/L were prepared with deionized water and raw waters from the Changxing and Fengshan Water Treatment Plants in Taiwan to assess the effects of water matrices on nano-TiO2 behavior during water treatment. After the laboratory simulated water treatment, including pre-chlorination, coagulation, sedimentation, filtration and post-chlorination, the residual Ti concentration ranged from 2.7 to 47.4% in different treatment units and overall removal efficiency was between 52.6% and 97.3% in all cases except for nano-TiO2 at concentration of 0.1 mg/L. Overall removal efficiency for the TiO2 at 10 mg/L concentration ranged from 9.3 to 53.5%. Sedimentation (after coagulation) and filtration were the most important processes for removing nano-TiO2 due in part to particle agglomeration, which was confirmed by size distribution and zeta potential measurements. The size of nano-TiO2 increased from 21–36 nm to 4490 nm in the supernatant after sedimentation, and subsequent filtration treatment further removed all agglomerates at size > 1 μm. Zeta potential revealed interactions between nano-TiO2 particles and anionic functional groups or negatively-charged natural organic matters, leading to a decrease in surface charge. After sedimentation and filtration, the zeta potential of supernatants and filtrates were close to zero, meaning the absence of nanoparticles. The highest Ti removal after sedimentation occurred in Fengshan raw water due to higher ionic strength and coagulant dosage applied. On the other hand, the surfactant additives in TiO2(S) promoted dispersion of nano-TiO2 particles, which in turn led to lower particle removal. SEM images of nanoparticles after chlorination or coagulation revealed the coverage of nano-TiO2 particles by viscous substances and formation of colloidal structures. © 2017 Elsevier B.V.

Chen Y.-C.,National Taipei University of Technology | Tan C.-H.,Agricultural Engineering Research Center | Wei C.,National Taiwan University | Su Z.-W.,National Taipei University of Technology
International Journal of Environmental Research and Public Health | Year: 2014

This study applied remote sensing technology to analyze how rivers in the urban environment affect the surface temperature of their ambient areas. While surface meteorological stations can supply accurate data points in the city, remote sensing can provide such data in a two-dimensional (2-D) manner. The goal of this paper is to apply the remote sensing technique to further our understanding of the relationship between the surface temperature and rivers in urban areas. The 2-D surface temperature data was retrieved from Landsat-7 thermal infrared images, while data collected by Formosat-2 was used to categorize the land uses in the urban area. The land surface temperature distribution is simulated by a sigmoid function with nonlinear regression analysis. Combining the aforementioned data, the range of effect on the surface temperature from rivers can be derived. With the remote sensing data collected for the Taipei Metropolitan area, factors affecting the surface temperature were explored. It indicated that the effect on the developed area was less significant than on the ambient nature zone; moreover, the size of the buffer zone between the river and city, such as the wetlands or flood plain, was found to correlate with the affected distance of the river surface temperature. © 2014 by the authors; licensee MDPI, Basel, Switzerland.

Kuo Y.-M.,Ming Dao University | Wang S.-W.,Agricultural Engineering Research Center | Wang S.-W.,China University of Technology | Jang C.-S.,Kainan University | And 2 more authors.
Atmospheric Environment | Year: 2011

Several heavily polluted industrial parks are located in the coastal area of Kaohsiung city, which the Taiwan EPA has declared to be the worst air quality region in Taiwan. This research used dynamic factor analysis (DFA) to investigate the source contributions of PM2.5 by monitoring data collected at the four aerosol supersites in Southern Taiwan throughout 2009. Dynamic factor analysis is a technique used to reduce or summarize the dimensions being studied, and is a proven useful technique for this type of study, which handles complex gaseous pollutant conditions. The results of the optimal DFA model showed that PM2.5 concentrations in the Kaohsiung metropolis were primarily influenced by explanatory variables that included sulfate (SO42-), nitrate (NO3-), carbonaceous aerosols, carbon monoxide (CO), sulfate oxides (SO2), nitrate oxides (NO2), and relative humidity (RH). The concentrations were also slightly affected by two common trends representing unexplained variables. Particulate sulfate was the primary variable among the identified explanatory variables. The optimal DFA model satisfactorily accounted for the fluctuations in PM2.5 for the four aerosol supersites (coefficient of efficiency = 0.93). That is, the extreme concentrations of PM2.5 could be successfully described by considering the selected explanatory variables. We used this DFA model successfully to research PM2.5, and future studies concerned with Kaohsiung air quality should consider gaseous pollutants and human activities that our model has identified. © 2011.

Liang C.-P.,Fooyin University | Liu C.-W.,National Taiwan University | Jang C.-S.,Kainan University | Wang S.-W.,Agricultural Engineering Research Center | Lee J.-J.,Environmental Protection Administration
Journal of Hazardous Materials | Year: 2011

This paper assesses health risks due to the ingestion of inorganic arsenic from fish and shellfish farmed in blackfoot disease areas by general public in Taiwan. The provisional tolerable weekly intake of arsenic set by FAO/WHO and the target cancer risk assessment model proposed by USEPA were integrated to evaluate the acceptable consumption rate. Five aquacultural species, tilapia (Oreochromis mossambicus), milkfish (Chanos chanos), mullet (Mugil cephalus), clam (Meretrix lusoria) and oyster (Crassostrea gigas) were included. Monte Carlo analysis was used to propagate the parameter uncertainty and to probabilistically assess the health risk associated with the daily intake of inorganic As from farmed fish and shellfish. The integrated risk-based analysis indicates that the associated 50th and 95th percentile health risk are 2.06×10-5 and 8.77×10-5, respectively. Moreover, the acceptable intakes of inorganic As are defined and illustrated by a two dimensional graphical model. According to the relationship between Cinorg and IRf derived from this study, two risk-based curves are constructed. An acceptable risk zone is determined (risk ranging from 1×10-5 to 6.07×10-5) which is recommended for acceptable consumption rates of fish and shellfish. To manage the health risk due to the ingestion of inorganic As from fish and shellfish in BFD areas, a risk-based management scheme is derived which provide a convenient way for general public to self-determine the acceptable seafood consumption rate. © 2010 Elsevier B.V.

Maji S.K.,National Taiwan University | Wang S.-W.,Agricultural Engineering Research Center | Liu C.-W.,National Taiwan University
Desalination and Water Treatment | Year: 2013

Iron-oxide-coated natural rock (IOCNR) was used as an adsorbent of arsenate, As(V), from aqueous solution. Batch adsorption studies were performed at 25 ± 2°C and pH 5.7 ± 0.2 with agitation at 200 rpm. Based on a batch study, 0.148 mm particles were adopted in this investigation. A 5 g L-1 dose of adsorbent removed ~99.6% As(V) from the aqueous media within a shaking time of 4 h when the initial As(V) concentration was 3 mg L-1. The adsorption process followed the pseudo-second-order kinetic model. The maximum adsorptive capacity of IOCNR was calculated from the Langmuir isotherm 16.92 mg g-1. The D-R isotherm revealed the nature of the adsorption process. The dimensionless parameter (RL) and Gibbs free energy changes (ΔGo) suggest that the process is favorable and spontaneous. The study was performed in the presence of different coexisting ions, including organic contaminants, at various pH values of the medium, to determine their effects on the removal of As(V). Film diffusion controlled of the process was evidenced from the Df value and multiple interruption tests. The As(V) removal efficiency (%) was compared with that of the patented adsorbent LEWATIT FO36. Finally, the IOCNR has been applied to remove arsenic from real arsenic-bearing sample. © 2013 © 2013 Balaban Desalination Publications.

Chen F.-W.,National Taiwan University | Chen F.-W.,Agricultural Engineering Research Center | Liu C.-W.,National Taiwan University
Paddy and Water Environment | Year: 2012

In this article, we used the inverse distance weighting (IDW) method to estimate the rainfall distribution in the middle of Taiwan. We evaluated the relationship between interpolation accuracy and two critical parameters of IDW: power (α value), and a radius of influence (search radius). A total of 46 rainfall stations and rainfall data between 1981 and 2010 were used in this study, of which the 12 rainfall stations belonging to the Taichung Irrigation Association (TIA) were used for cross-validation. To obtain optimal interpolation data of rainfall, the value of the radius of influence, and the control parameter-α were determined by root mean squared error. The results show that the optimal parameters for IDW in interpolating rainfall data have a radius of influence up to 10-30 km in most cases. However, the optimal α values varied between zero and five. Rainfall data of interpolation using IDW can obtain more accurate results during the dry season than in the flood season. High correlation coefficient values of over 0. 95 confirmed IDW as a suitable method of spatial interpolation to predict the probable rainfall data in the middle of Taiwan. © 2012 Springer-Verlag.

Chen F.-W.,Agricultural Engineering Research Center | Liu C.-W.,National Taiwan University
Irrigation and Drainage | Year: 2015

The purpose of this study was to evaluate the feasibility of using reclaimed water for cucumber irrigation. The experiment was conducted using raw canal water, and water reclaimed from treated wastewater using a natural recycling treatment system. The raw water quality met the Irrigation Water Quality Standards of Taiwan. The water quality of reclaimed water was treated within the ranges of DO: 3.9-8.4 (mg l-1); pH: 6.5-7.8; EC: 206-587 (μs cm-1, 25 °C); SS: 0.1-11.8 (mg l-1); NH4-N: 0-18.16 (mg l-1) and BOD: 0.1-1.8 (mg l-1). The experimental period for cucumber growth was 75 days. Rg was defined as the different multiple of plant growth and used to estimate the effects of irrigation water quality. Furthermore, yield, weight, length, and diameter of cucumbers were used to quantify the influence of irrigation water quality on cucumber quality. Result shows that Rg was within the range (1.003-1.311). The heights of cucumbers grown using reclaimed water were longer than those grown using raw water. Comparing the yield, weight, length, and diameter of cucumbers irrigated by reclaimed water (RW) and by raw water (IW), the percentages of RW/IW were respectively 154, 96, 95.5 and 101%. Based on the results, this study concludes that using reclaimed water for cucumber irrigation is feasible. © 2015 John Wiley & Sons, Ltd.

Shih Y.-h.,National Chung Hsing University | Tai Y.-t.,Agricultural Engineering Research Center
Chemosphere | Year: 2010

Polybrominated diphenyl ethers (PBDEs) recognized as a new class of environmental persistent toxic contaminants have been distributed widely in the world. In this study, the synthesized nanoscale zerovalent iron (NZVI) in the laboratory was used to investigate the removal kinetics and mechanisms of decabrominated diphenyl ether (DBDE) at different pH. Within 40 min 90% of DBDE was rapidly removed by NZVI as compared to around 40 d needed for 24-fold weight of microscale ZVI. The removal by NZVI is much faster than that by microscale ZVI due to its high surface area and reactivity. At a different pH, the pseudo-first-order removal rate constants of DBDE linearly increased from 0.016 to 0.024 min-1 with the decreasing of aqueous initial pH values from 10 to 5. The degradation of DBDE with NZVI is favorable in an acid condition. The debromination pathways of DBDE with NZVI were proposed on the basis of the identified reaction intermediates ranging from nona- to mono-brominated diphenyl ethers (BDEs) for an acid condition and from nona- to penta-BDEs for an alkaline condition. The debromination of PBDEs from para positions is more difficult than that from meta or ortho positions. Adsorption on NZVI also plays a role on the removal of DBDE. These findings can facilitate the treatment and fate prediction of PBDEs with NZVI in the environment. © 2010 Elsevier Ltd.

Gazor H.R.,Agricultural engineering research institute | Roustapour O.R.,Agricultural engineering research center
International Food Research Journal | Year: 2015

The effects of pretreatment solution (dipping in boiling water, salty boiling water, ethil oleat) were studied on drying kinetic of sour cherry. The thin-layer drying of sour cherries were carried out at three air temperatures of 50, 60 and 70°C and airflow velocity of 1 m/s. The experimental data were fitted to several thin-layer drying models such as Newton, Henderson and Pabis, Page, Logarithmic, Approximate Diffusion, Two-term exponential, and Midilli et al.. Three statistical tools coefficient of determination (R2), reduced chi-square (x2) and root means square error (RMSE) were used to quantify the goodness of fit. According to the results, drying time of sour cherry samples dipped in salty boiling water solution was shorter than the pretreated samples and control treatments. Besids, The Midilli et al. and Logarithmic models were found to be most suitable in describing the drying characteristics of sour cherry respectively. The effective moisture diffusivity of sour cherries based on the analytical solution of Fick's second law ranged from 2.07×10-11 to 2.33×10-10 m2/s. Using of pretreated solutions caused to decreasing activation energy in sour cherry drying process. Activation energy values varied from 23.74 to 83.05 kJ/mol. © All Rights Reserved.

Chien C.-P.,Agricultural Engineering Research Center | Fang W.-T.,Agricultural Engineering Research Center
Paddy and Water Environment | Year: 2012

This research is to construct a water balance model to estimate the amount of return flow in an irrigation system. A simple computation framework for the model was established to include various irrigation applications in cropping seasons. The model was able to estimate evapotranspiration, deep percolation into groundwater aquifer, and return flow. Return flow can be split into two parts, which are surface and subsurface return flows. The water balance model was then applied at the irrigation system (rotational block No. 11-2 of five paddy field units) which is operated by the Taoyuan Irrigation Association in Taiwan as an example. Two study cases were simulated, in which one was for using return flow and the other one was for using no return flow. The study period for the model simulations is the first rice cropping term in 2010 which was from February 16 to July 10. As a result, return flows calculated by the model were 27, 27, 34, and 39% of outflows for sandy loam, sandy clay, clay loam, and light clay soil, respectively. Irrigation water at the downstream field unit with use of return flow was supplemented by the upstream field units, and the amount is 5-8% of irrigation water for using no return flow. Furthermore, it can be seen from the simulations that increases in irrigation water provide increases of return flow. Increases of irrigation water result in slight increases of subsurface return flow, while increases of irrigation water cause nearly none of change in deep percolation. © 2011 Springer-Verlag.

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