Reduction of alkali supplement in a pilot-scale thermophilic multi-staged UASB reactor treating alcohol distillery wastewater

One of the main disadvantages of anaerobic wastewater treatment at a low pH is the significant operational cost due to the addition of necessary alkali. To reduce alkali supplement and thus the cost, this study proposes a sequential multi-feed [SqMF] mode [distributed feeding] and effluent recycle [ER] mode. Experiments were conducted with a pilot-scale [2.5 m[3]] thermophilic [55°C] multi-staged up-flow anaerobic sludge blanket reactor. Alcohol distillery wastewater [shochu], a major source of industrial wastewater in Japan, was used for the study. The SqMF mode of operation [influent pH: 5.0; organic loading rate: 45 kgCOD/m[3]/day; HRT: 12 hours; influent COD concentration: 20,900 mgCOD/L] successfully reduced the alkali supplement [24% NaOH solution] requirement by 67.2% compared with the single-feed mode. For the ER mode operation [organic loading rate: 35 kgCOD/m[3]/day; HRT: 12 hours; influent COD concentration: 17,400 mgCOD/L], operation was possible without any alkali supplement since the system uses the alkalinity generated during microbial metabolism

Off-flavors removal and storage improvement of mackerel viscera by supercritical carbon dioxide extraction.

The oil in mackerel viscera was extracted by supercritical carbon dioxide (SCO2) at a semi-batch flow extraction process and the fatty acids composition in the oil was identified. Also the off-flavors removal in mackerel viscera and the storage improvement of the oils were carried out. As results obtained, by increasing pressure and temperature, quantity was increased. The maximum yield of oils obtained from mackerel viscera by SCO, extraction was 118 mgg(-1) (base on dry weight of freeze-dried raw anchovy) at 50 degrees C, 350 bar And the extracted oil contained high concentration of EPA and DHA. Also it was found that the autoxidation of the oils using SCO2 extraction occurred very slowly compared to the oils by organic solvent extraction. The off-flavors in the powder after SCO2 extraction were significantly removed. Especially complete removal of the trimethylamine which influences a negative compound to the products showed. Also other significant off-flavors such as aldehydes, sulfur-containing compounds, ketones, acids or alcohols were removed by the extraction.