การหมักร่วมระหว่างทะลายปาล์มเปล่ากับมูลสุกรในถังหมักไร้อากาศลิชเบดสำหรับการผลิตกรดไขมันระเหยง่าย

Thesis Ph.D.(Environmental Management)--Prince of Songkla University, 201

Comparing Low-Temperature Hydrothermal Pretreatments through Convective Heating versus Microwave Heating for Napier Grass Digestion

This study investigates the effects of convective hydrothermal pretreatment (CHTP) compared to microwave pretreatment (MWP) on the anaerobic digestion of hybrid Napier grass for biomethane production. For rapid estimation of methane yield (YCH4), enzymatic hydrolyzability (EH), whose test lasts only 2 days was used as a surrogate parameter instead of the biochemical methane potential (BMP) assay that normally takes 45–60 days. The relationship between EH and BMP was successfully modeled with satisfactory accuracy (R2 = 0.9810). From CHTP results, quadratic regression characterised by p < 0.0001 and R2 = 0.8364 shows that YCH4 increase was clearly sensitive to detention time at all CHTP temperatures. The maximal YCH4 achieved of 301.5 ± 3.0 mL CH4/gVSadd was 53.2% higher than the control. Then, MWP was employed at various power levels and microwave exposure times. Changes in lignocellulosic structure by Fourier-transform infrared spectroscopy (FTIR) and energy balance demonstrate that MWP caused more damage to plant cells, which proved more effective than CHTP. In the best conditions, approximately 50% of energy was needed for MWP to achieve the equivalent improvement in YCH4. However, CHTP is a more suitable option since waste heat, i.e., from a biogas CHP (combined heat and power) unit, could be used, as opposed to the electricity required for MWP

Solid-liquid anaerobic baffled reactor treating food waste

The characteristics of the sauce industrial wastewater is high organic degradable materials, it requires adequate treatment in order to process wastewater is technically and economically feasible. The main treatment to remove high content of organic material is anaerobic process. The presence of a preservative agent in wastewater would lead to disruption of the growth of micro-organisms. Slow the growth of anaerobic bacteria require a solids residence time (solid retention time, SRT) period in anaerobic reactors. This research is to observe the effect of input COD with constant sludge height to the removal of COD. Main equipment process of anaerobic reactor is baffled reactor. Activated sludge used are obtained from the tofu and tempe wastewater treatment unit in Semarang while synthetic wastewater was obtained from dissolution of preservative material product (Del monte sauce). The control parameter was: pH, alkalinity, the ratio of COD: N: P, baffled configuration, wastewater flow rate (20 L/day), addition of micro-nutrient and height of suldge. The variable of reseach was initial COD input. The observed response is: COD removal and pH. The total COD removal for low organic loading (2369.7 mg COD/L) is 80.36 to 98.03 % and for high organic loading (7334 mg COD/L) is 98.15