Department of Biological Systems Engineering, University of Wisconsin-Madison, 460 Henry Mall, Madison, WI, USA.
Bioresour Technol. 2011 Nov;102(21):9891-6. doi: 10.1016/j.biortech.2011.08.028. Epub 2011 Aug 11.
Recycling of anaerobically-digested thin stillage within a corn-ethanol plant may result in the accumulation of nutrients of environmental concern in animal feed coproducts and inhibitory organic materials in the fermentation tank. Our focus is on anaerobic digestion of treated (centrifugation and lime addition) thin stillage. Suitability of digestate from anaerobic treatment for reuse as process water was also investigated. Experiments conducted at various inoculum-to-substrate ratios (ISRs) revealed that alkalinity is a critical parameter limiting digestibility of thin stillage. An ISR level of 2 appeared optimal based on high biogas production level (763 mL biogas/g volatile solids added) and organic matter removal (80.6% COD removal). The digester supernatant at this ISR level was found to contain both organic and inorganic constituents at levels that would cause no inhibition to ethanol fermentation. Anaerobic digestion of treated-thin stillage can be expected to improve the water and energy efficiencies of dry grind corn-ethanol plants.
在玉米乙醇厂内对厌氧消化的稀酒糟进行再循环，可能会导致动物饲料副产物中环境关注的营养物质的积累，以及发酵罐中抑制性有机物质的积累。我们的重点是处理过的（离心和石灰添加）稀酒糟的厌氧消化。还研究了厌氧处理的消化物作为工艺水再利用的适宜性。在不同的接种物与底物比（ISR）下进行的实验表明，碱度是限制稀酒糟消化的关键参数。基于高沼气产量（添加的挥发性固体中 763 毫升沼气/克）和有机物去除率（80.6% COD 去除率），2 的 ISR 水平似乎是最佳的。在这个 ISR 水平下，发现消化器的上层清液中含有有机和无机成分，这些成分不会对乙醇发酵造成抑制。预计对处理过的稀酒糟进行厌氧消化可以提高干磨玉米乙醇厂的水和能源效率。
