Nitrogen and Phosphate Transformation Modeling for Wastewater in Multi-Soil-Layering System
| Autor: | Huang Yu-Ling, 黃淯泠 |
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| Rok vydání: | 2017 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 105 Multi-Soil Layering System (MSL) is an emerging technology for waste water treatment., which is based on soil mixing black (SMB) and permeability layer (PL). In this thesis, zeolites was utilized as adsorption and filtration materials in MSL due to their high cation exchange capacity (CEC) and adsorption capacity, however, the cost was high as well. In order to overcome this issue, light expanded clay aggregate (LECA) was investigated to instead of zeolite in MSL system, which is cheaper and environment-friendly material. First, characterization of zeolites and LECA by scanning electron microscopy (SEM) and X-ray fluorescence (XRF) analyses showed that both of them had high porosity and rich with SiO2, Al2O3 and Fe2O3. The maximum adsorption capacity were 14.7 mg N/g and 10.8 mg P/g for zeolite. However, the adsorption performance of LECA did not show affinity for ammonium and phosphate. The MSL system with zeolites had both chemical adsorption and biological reaction mechanism for ammonium, whereas, the MSL system with LECA only relied on biological reaction. In addition, both of these two systems had chemical reaction with phosphate to produce ferrous sulfate precipitate. According to the experimental data form these two MSL system, the regression methodology were utilized to establish ammonia nitrogen and total phosphorus removal model. The result showed that when concentration of ammonia nitrogen 25 mg/L and total phosphorus 5 mg / L in domestic wastewater, the hydraulic load rate was 1.43 m3/m3/day. The mass balance of ammonia nitrogen in the MSL system was approximately 4% adsorbed through zeolites, 67.5% gasified and 28.5% transformed to nitrate through nitrification and denitrification. Until the zeolite adsorption saturation can be operated for 8.2 years. Furthermore, Phosphorus was converted to ferrous phosphate, around 91%. The lifetime of adding iron in MSL system was enough to use for 10 years. On the basis of results, LECA showed the feasibility in the MSL system compared with zeolite. According to LECA can using low hydraulic loading rate (HLR) to compensate for lack of adsorption, and also cooperate with the microbial decomposition simultaneously to achieve the same efficiency of zeolite. In addition, it can save 30% of material cost in the MSL system. Therefore, the combination of LECA with MSL system has application potential for wastewater industry. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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