Effect of constant and fluctuating temperature on the performance and stability of solar septic tanks | |
| Author | Mayulee Suwannakeaw |
| Call Number | AIT Thesis no.EV-18-17 |
| Subject(s) | Septic tanks--Environmental aspects Sewage--Purification--Anaerobic treatment |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Environmental Engi neering and Management |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis ; no. EV-18-17 |
| Abstract | A ―Solar Septic Tank‖ as an innovative onsite wastewater treatment utilizes solar - heated water to increase treatment pe rformance and pathogen inactivation efficiencies in the reactors. Water temperatures in the solar septic tank are maintained in range of 40 - 55 oC, resulting which an increased rate of biodegradation would consequently reduce in - tank solid accumulation. Sin ce typical operating conditions such as flow rate, daily temperature, feeding pattern and organic nitrogen/loading rates of the decentralized/onsite wastewater treatment systems are always changing, it would usually results in the fluctuation of treatment efficiencies over timespan. This research aimed to determine the limits of operation of the solar septic tank, by considering dynamics patterns of the intermediate products of anaerobic process and treatment efficiencies in responding to various operating conditions. A laboratory - scale solar septic tank unit with a working volume of 50 L and in circular shape was tested at Ambient Laboratory at the Asian institute of Technology (AIT), Thailand. To maintain a water temperature of 50 ° C, an electric heater, with temperature controller was installed inside experiment unit, insulated with sand. It was operated for 4 months by continuously feeding the concentrated black water at an HRT of 24 h. The experimental design during this study was evaluation solar sept ic tank performance relation between temperature and accumulation intermediate production by simulated daily temperature change. The result of TCOD removal at constant 50° C was 71% higher not much than fluctuating temperature of 68.58%, while at fluctuati ng temperature higher SCOD removal than constant 50° C to be 56.83% and 43.8%, respectively. The average percent removals efficiencies of TS and TVS tank in both phases were not much different as 50 and15.64% of constant 50° C and fluctuating temperature t o be 57.81and 15.77%. Methane production of temperature 50°C and temperature variation have shown 70.29 and 58.0%, respectively. the average of methane production to be 1.307 L/d and 1.56 L/d, respectively because temperature variation generated gas produ ction more than constant temperature that might be effect from diverse group of microorganisms relate with methanogenic because of vary range of temperatures. The part of accumulated VFA of temperature daily 42°C was higher than temperature at 65°C and 55 °C and also constant temperature while 65°C generated VFA accumulations higher than 55°C The hypothesis of this point might be relate with acid forming and methanogenic bacteria. The major of individual VFA Acetic acid at temperature 50°C and varies temper ature categorized into 3 time as 3 range of temperature which the range were 21.0 - 109.6 and 31.27 - 203.84, 13.20 - 89.90 and25.68 - 135.95mg/L, respectively. |
| Year | 2018 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. EV-18-17 |
| 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) | Annachhatre, Ajit P.;Anal, Anil Kumar;Tatchai Pussayanavin; |
| Scholarship Donor(s) | Royal Thai Government Fellowship; |
| Degree | Thesis (M. Sc.) - Asian Institute of Technology, 2018 |