Treating TPHs-contaminated groundwater using bio-pellets

• Main Authors: YANG, DUN-SHENG, 楊敦勝
• Other Authors: CHEN, SHYI-TIEN
• Format: Others
• Language: zh-TW
• Published: 2019
• Online Access: http://ndltd.ncl.edu.tw/handle/t845sk

碩士 === 國立高雄科技大學 === 環境與安全衛生工程系 === 107 === The increase of transportation motors and the need of industrial raw materials result in the demand of oil raises year after year. During oil storage and handling spills may happen, such as pipe leaks, transportation spills and under storage tank twisted and broken. All of these increase the risk of soil and groundwater contamination. Solubility and density of the oil affect its fate and distribution in the groundwater. Microbes, especially the acclimated ones, show a great ability in oil removal, yet in the groundwater the microbial growth conditions are confined. Lack of nutrients and oxygen are commonly seen problems. Thus, how to supply the additional C/N/P along with oxygen, and to enhance the contact between microbes and oil are two key issues in dealing with the oil-contaminated groundwater. In this study, biopellet with different density was to be made. Features like long floating time, continuous release of nutrients and oxygen for microbes are of desired. Thus, the objectives of this study included: (1) to assess the distributions of various TPHs in groundwater, (2) to manufacture the pellets embedded with microbes, nutrients, and oxygen at density control materials, and (3) to confirm the TPH removal efficiency of the groundwater using the manufactured pellets. The study began with employing GC-MS/FID analysis to confirm the oil distribution in a pilot column reactor, followed by treating desiel in groundwater by the manufactured biopellets. The results obtained included: (1) A database with 7 GC-MS spectra of various oils was constructed. If more oil spectra added, it may serve as a tool for unknown oil identification. (2) Ingredient analysis of oil distribution at different water levels found that. For gasoline, the BETX were the most dominant species and were distributed mostly on the water surface of the column. For diesel, C12-C21 alkanes were observed mainly on the top 10 cm of the column. For the heavy oil, no solubility was observed. Yet, dissolving the TPHh by surfactant to suspend the ingredients in water appeared applicable. (3) Volatilization of TPHd was minimal in the column runs; the acclimated microbes removed TPHd faster w.r.t the controls, which rate increased from 34.1 to 46.2 mg/L-d w.r.t if acclimation accomplished. With regular mixing the TPH removal rate increased, and the reaction stopped if TPHs content was too high. (4) A pellet, coated with 3 levels of alginate, floated for more than 25 days before its breakage. In each 6-g pellet, there were 3.1398 g-C, 0.0102 g-N, 0.001914 g-P, 0.25 g-CaO2 in capsule, 0.0576 g-metals, 1 g-sodium alginate, 0.312 g-H2O and 1.228 g-other. (5) Treatment with the bio-pellet showed that 99% of the spiked 500 mg/L TPHd in water were removed with microbial count at 107 CFU/mL after day 8. The microbial consumptions of the N, P and oxygen were obvious along with the removal of TPHd during the reaction period. The remaining 1% of the TPHs was C13-C18. When the initial TPH raised to 1500 mg/L, the removal rate increased to ~45 mg/L-d, and all TPHs were removed in 22 days if the pellets presented.