Yi-Chu Huang

Variation of groundwater quality in seawater intrusion area using cluster and multivariate factor analysis

Numerous monitoring data and water quality index obtained from 76 regional shallow-layer monitoring wells are simplified and classified by applying the multivariate statistical methods such as factor and cluster analysis to search for the interrelation between the water quality parameters, factors representing the characteristics as well as possible pollution sources of groundwater quality in Pingtung Champaign, Taiwan. Four principal factors were recognized in concerned area using principal component analysis (PCA) including salinization factor, mineralization factor, inorganic factor, and inorganic reduction factor. All four factors can interpret 81.0% variances of the integrated groundwater characteristics. In addition four clusters were classified according to the similar and dissimilar characteristics of water quality of monitoring wells in Pingtung Champaign. The results showed that the groundwater quality of hinterland was better than that of coastal area. Some coastal areas have already been affected by the seawater intrusion resulting in aquifer salinization. Multivariate statistical methods provided by this study can not only reduce the harassment of the missing items of monitoring water quality, but also refer as a management alternative for groundwater resources.

Dechlorination of tetrachloroethylene in water using stabilized nanoscale iron and palladized iron particles

AbstractChlorinated solvents such as tetrachloroethylene (PCE) in aquifers should be remediated due to their toxicity that limited the use of groundwater resources. Nanoscale zero-valent iron (NZVI) and palladized/iron (Pd/Fe) bimetallic particles were synthesized and employed to react with PCE in water to investigate its degradation behaviors. Batch tests were conducted in a 1 L serum bottle under airtight and anaerobic conditions with parameters of Pd mass contents, temperature, pH, and dispersant. The results showed that specific reaction rate constants (kSA) of 5 mg L−1 PCE degraded by metal particles at 30°C in the absence of dispersant enhanced with higher Pd mass contents on the Pd/Fe particles. Degradation rates of PCE increased as the reaction temperature was raised from 20 to 40°C. Carboxymethyl cellulose (CMC), a dispersant, enhanced the kSA values of NZVI and 1:100 Pd/Fe particles by a factor of about 33 and 4 at 30°C, respectively. The tests of pH control with buffer solution indicated that P...

Sustainable management strategies for an urban-type and low dissolved oxygen stream using measured biochemical coefficients

Abstract A water quality model, QUAL2K, with the measured biological coefficients was employed to develop sustainable management strategies for an urban-type stream. To master the data of hydrological and receiving water quality, three surveys were conducted at 20 sampling stations along the Wan-Nian stream in the Pingtung city of southern Taiwan. Then the biochemical coefficients including deoxygenation, nitrification, and reaeration rate coefficients, and sediment oxygen demand were measured and incorporated with influent pollutant loadings and boundary conditions to calibrate and verify the developed model. Simulation evaluated with the mean absolute percentage error method fits reasonably well except for a suspended solid sampled on 16 January 2011. The improvement goal for attaining the water quality of the Wan-Nian stream was set at Class C regulated by the Taiwan EPA. The assimilative capacity of the stream studied to Carbonaceous Biochemical Oxygen Demand (CBOD) and NH3–N was estimated to be aroun...

Water Quality Management Strategies for Various River Flows with QUAL2K Model

This study utilizes the river and stream water quality (QUAL2K) model as a tool to simulate and forecast the water quality and then to develop the management strategies for various flow rates above the Kaoping weir of Kaoping River in Taiwan. Model results based on the river assimilative capacity of four various flow rates including Q95, Q75, Q60, and Q25 were conducted to determine the corresponding amounts of pollution reduction. The average pollution reduction ratios of biochemical oxygen demand (BOD5) and ammonia nitrogen (NH3-N) should at least reach to 42.0% and 28.3% respectively to meet the restoration goals of Class A water quality standards regulated by Taiwan. The modeling results demonstrate that an increase of water extraction rates in the upstream reaches will have significant adverse effects on the water quality of the Kaoping River. Higher water extraction rates will lower the assimilative capacity that reduces the buffering capacity of river. It also induces that the water quality is susceptible to the impacts of the influent pollutant loads from the tributaries or drainages.

Variations of model performance between QUAL2K and WASP on a river with high ammonia and organic matters

AbstractTwo water quality models, Water Quality Analysis Simulation Program (WASP) and QUAL2K, were selected and applied to evaluate the performance variations of a river with high ammonia and organic matters in southern Taiwan. Through the appraisal of fit levels with the mean absolute percentage error method, the overall model results of WASP were better than those of QUAL2K. Assimilative capacity of the concerned Tonggang River simulated by WASP is 16.5% more than that by QUAL2K to achieve the Class B water quality standards regulated by Taiwan EPA. The total invested capital for clean pig farming and sewage interception estimated by WASP was

Water Quality Management Scenarios for the Love River in Taiwan

65,402 and

Back-Propagation Neural Network on Characterization of Groundwater Quality in Pingtung Champaign, Taiwan

12,381,600 less by QUAL2K, respectively. Levels of water quality improvement and respective costs of several proposed pollutant reduction strategies including sewage interception and clean pig farming practice were also evaluated. This study demonstrates that variations of the model results occurs as using WASP and QUAL2K to estimate the improvement e...

Emissions of polycyclic aromatic hydrocarbons (PAHs) from the pyrolysis of scrap tires

The Love River with a length of 16 km along the main stream and a catchment area of 62 km2 is an urban-type tidal stream and its estuary locates at the Kaohsiung Harbor in southern Taiwan. The majority of municipal wastewater directly discharged into the Love River, resulting in deterioration of water quality, especially the low dissolved oxygen (DO) problem. The Water Quality Analysis Simulation Program/Eutrophication (WASP/ EUTRO) model was applied to simulate the fate and transport of pollutants in the Love River. The results showed spatial distributions of electrical conductivity (EC), suspended solids (SS), carbonaceous biological oxygen demand (CBOD5), ammonia nitrogen (NH3-N), and DO were well reproduced by the mass transport model. A comparison between calculated results and field data shows a reasonable agreement. The study demonstrates simulation analysis using WASP is promising for water quality managements of an urban-type river.

Emissions of Polychlorinated Dibenzo-p-dioxin and Polychlorinated Dibenzofuran from Motorcycles

Four clusters were classified according to the similarities and dissimilarities of water quality data collected from 1998 to 2008 of the 76 monitoring wells in Pingtung Champaign. The results showed that the groundwater quality of hinterland was better than that of coastal area. Some wells along the coastal areas have already been influenced by seawater intrusion incurring aquifer salinization. The overall grouping accuracy of cluster analysis (CA) for rainy and dry seasons was 95.8% and 97% according to the discriminant analysis, respectively. The results from the back-propagation neural network (BPNN) model showed no significant variations of nitrate (NO3-N) between the estimated and observed data, however most of the estimated total organic carbon (TOC) data were higher than the observed ones. It meant that the groundwater quality may be susceptible to the impacts of organic pollutants in the future within 90% confidence intervals. The results of this study show that application of CA and BPNN can simplify complex non-linear systems, moreover, groundwater quality can be estimated and modeled via monitoring data over the years. The modeling results can be utilized to frame the corresponding strategies to reduce the monitoring cost and to enhance the cost-effective benefits. The proposed analysis methods can be referred as a management plan for groundwater resources and pollution prevention to achieve the goal of early warning.