| Author | Varinporn Asokbunyarat |
| Call Number | AIT Thesis no.EV-11-16 |
| Subject(s) | Groungwater--Pollution
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| Note | A thesis submitted in partial fulfillment of requirements for the degree of Master of Engineering in Environmental Engineering and Management |
| Publisher | Asian Institute of Technology |
| Abstract | Groundwater is the major source of usable drinking water worldwide. The most important and widespread pollutant in groundwater is nitrate. The main sources of nitrate pollution are crop fertilization and animal waste. High groundwater nitrate ingestion leads to human health problems including the blue baby syndrome in infants. Available technologies to remove nitrate include membrane separation and ion exchange. Nevertheless, these technologies are expensive process and produce nitrate concentrated waste streams. Therefore, other approach including biological denitrification is being investigated. One of the envisioned best alternatives is permeable reactive barrier (PRB) due to its low prices and its efficiency compared to other technologies. The objective of this study is to select the suitable substrates used as electron donors for groundwater nitrate treatment, evaluate the appropriate hydraulic retention time in PRB, and investigate the effect of nitrate concentration. As the result, the suitable substrates for PRB, which were investigated by batch experiment, were cotton & softwood formula and rice straw, cotton & softwood formula with the appropriate residence time 2 days. The percentages of nitrate removal efficiency were up to 98%, which the residue nitrate concentration fell below 1 mgNO₃--N/L after 9 day. The rate constants (k) of cotton & softwood formula; and rice straw, cotton & softwood formula were 2.914 and 1.781 respectively. The nitrate concentration reduced from 24.67 to < 15 mgNO₃--N/L in both cotton & softwood reactors, which the percentages of nitrate removal were 74% and 49% respectively. On the other hand, The nitrate concentration reduced from 24.67 to < 2 mgNO₃--N/L in both rice straw, cotton & softwood reactors, which the average denitrification rate was 0.0023 mgNO₃--NL-1d-1g-1sub, the average amount of nitrate removal was 1.812 g and the average percentage of nitrate removal was >94%. Clearly, the both rice straw, cotton & softwood reactors showed better nitrate reduction than the both cotton & softwood reactors. Moreover, increasing inlet nitrate concentrations caused a drop in reactor performances. |
| Year | 2011 |
| Type | Thesis |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Department of Energy and Climate Change (Former title: Department of Energy, Environment, and Climate Change (DEECC)) |
| Academic Program/FoS | Environmental Engineering and Management (EV) |
| Chairperson(s) | Annachhatre, Ajit P.; |
| Examination Committee(s) | Visvanathan, C.;Preeda Pakpian; |
| Scholarship Donor(s) | Royal Thai Government;Asian Institute of Technology Fellowship; |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 2011 |