Constructed wetland in a living wall system for pathogen removal to treat the septic tank effluent | |
| Author | Apinya Suwannakaew |
| Call Number | AIT Thesis no.EV-23-02 |
| Subject(s) | Water--Purification--Microbial removal Wastewater--Treatment Septic tanks--Environmental aspects |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Environmental Engineering and Management |
| Publisher | Asian Institute of Technology |
| Abstract | Nowadays, the septic tank was popular in worldwide due to technology performance. the number of coliform bacteria is 106 to 2×108 MPN/100 mL which are still high for reuse, recycling and resource recovery when compared with national standards and the global standard (ISO30500) (Polprasert & Rajput, 1982; Koottatep et al., 2021). Therefore, to enhance septic tank efficiency, the novel constructed wetland should be provided as a post-treatment system. Furthermore, to solve land limitation of constructed wetland, they should have a new design to be living wall systems (CW-LWS). The overall objective in this research is to improve media as well as design of living wall constructed wetland to enhance pathogen removal performance of constructed wetland. The developed media include MgO, bentonite, zeolite and spent tea leaves. Furthermore, adsorption isotherm including Langmuir, Freundlich and Koble corrigan isotherm were used to describe adsorption characteristics. R2 of media fitting with Koble corrigan isotherm shows heterogeneous adsorption characteristic. To investigate appropriate bed depth of CWs (0.15 and 0.25 m), the system operated conditions at HRT 3 hr for treating septic tank effluent. COD, TSS, pH in all unit systems was over the national standard of Thailand as well as ISO30500. TKN in all unit systems followed Thailand standard and ISO30500. Furthermore, CW-15 and CW-25 have the highest performance in total phosphorus removal around 83.926+_3.36 and 86.29+_3.15 mg/L, respectively. For FCB and E.coli removal performance, this parameter depends on pH. In the beginning, the operation unit can treat FCB and E.coli to follow WHO standard, US.EPA and ISO30500. Nevertheless, after operation over 20 days, the operation system has lower performance for treating FCB and E.coli due to decreased pH. Furthermore, high initial amounts of the FCB and E.coli negatively affect removal efficiency. For phosphorus removal mechanisms, the main mechanisms for phosphorus removal was adsorption followed by precipitation process. The result was observed that Painted Nettle has the highest biomass increasing and phosphorus uptake capacity. Window- leaf plants have the lowest tolerance in high pH. |
| Year | 2023 |
| 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) | Thammarat Koottatep |
| Examination Committee(s) | Cruz, Simon Guerrero;Tatchai Pussayanavin |
| Scholarship Donor(s) | Her Majesty the Queen’s Scholarships (Thailand) |
| Degree | Thesis (M. Sc.) - Asian Institute of Technology, 2023 |