| Summary: | 碩士 === 國立屏東科技大學 === 環境工程與科學系所 === 99 === The Tungkang River is one of the major rivers in Kaohsiung and Pingtung areas. Previous studies for analysis on various types of wastewater pollution loads in the Tungkang River have indicated that the order of the amount of waste discharge was pasturage (66.66%), municipal (31.30%), and industrial (2.04%) wastewater for biochemical oxygen demand (BOD), pasturage (74.83%) and municipal (25.17%) wastewater for ammonia nitrogen (NH3-N) and pasturage (70.72%), municipal (27.40%), and industrial (1.88%) wastewater for suspended solids (SS), respectively. Therefore, pasturage wastewater had been identified as the major source of pollution in the Tungkang River.
The annual flow of Tungkang River is abundant and stable. Water pumping from the Gangci Pumping Station is one of the water sources of the Fongshan Reservoir for industrial purposes. For smoothing the water shortage problem of southern region, this study mainly aims at the investigation of river pollution to analyze and estimate to master the source and amount of pollution for the Tungkang River. The Gangci Pumping Station was selected as a station index for water quality improvement. The measures for improvement of pollution loading were evaluated by the water quality model.
This study utilizes the enhanced stream water quality (QUAL2K) model as a tool to simulate and forecast the water quality of various pollution control measures and then to develop the management strategies to meet the restoration goals of Class B water quality standards regulated at the Gangci Pumping Station of Tungkang River. The improvement measures to the effects of the parameters of BOD, NH3-N and SS were used to draw up the targets of the strategies of pollution control, and then evaluated the applicability of model simulation. The model parameter values of the deoxygenation rate (K1) of 0.2-0.4 day-1, reaeration coefficient (K2) of 0.78-6 day-1, nitrification rate (Kn) of 0.05-0.1day-1, and sediment oxygen demand (SOD) of 0.37-3.2 g O2 m-2 day-1 were measured in-situ, while the dispersion coefficient and SS sedimentation rates used adopted the values listed in the literatures focused on the southern river of Taiwan. According to the analysis of assimilative capacity and pollution reduction, the reduction ratios of SS, BOD and NH3-N should at least reach to 6.7%, 53.8% and 75.6% respectively to meet the restoration goals of Class B water quality standards regulated for the reaches above the Gangci Pumping Station.
The simulation results indicate that reduction strategies for sewage interception 90%, SS and BOD have reached Class B water quality standards regulated but NH3-N still needs to cut down 31%. The improvement effect of water quality is better for 100% of measures of clean pig farming, the total reduction ratios of BOD and NH3-N at least need to decrease 12% and 9% respectively to achieve Class B water quality standards regulated. The improvement of water quality for integrated reduction strategies of inspection enforcement, sewage interception 50% and clean pig farming 75% was better, BOD and SS could achieve Class B water quality standards regulated except NH3-N. If the water quality standard for source of drinking water was used as a goal, NH3-N should at least cut down 6% and 12% for the reduction strategies of inspection enforcement or construction of sewage systems of Neipu, Wanluan, Chaozhou respectively to meet the restoration goals.
The overall river water quality index (WQI) for the tributaries of the Tungkang River was significantly raised for clean pig farming 100%. The improvement ratios of WQI for integrated reduction strategies of sewage interception 50% and clean pig farming 75% was higher, while other improvement measures had little effect. With reduction strategies of sewage interception 90% or clean pig farming 100% or inspection enforcement, sewage interception 50% and clean pig farming 50%, the water quality of the Wukuei Bridge, Singshe Bridge, Kangtung Bridge and Gangci Pumping Station along the main stream upgraded from Class IV to Class III. The results of this study can be employed to estimate the improvement effects of water quality for various reduction strategies in the Tungkang River and can also provide a reference for water quality management and pollution control in the future.
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