Topic
Hydraulic retention time
About: Hydraulic retention time is a research topic. Over the lifetime, 6406 publications have been published within this topic receiving 151005 citations.
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TL;DR: In this paper, a 3.0-l upflow reactor was used to investigate individual effects of hydraulic retention time (HRT), chemical oxygen demand (COD) concentration in wastewater (14- 36 g COD/l), pH (4.5-6.0), and temperature (20-55°C) on bio-hydrogen production from the wastewater.
413 citations
TL;DR: A mediator-less microbial fuel cell was used as a biochemical oxygen demand (BOD) sensor in an amperometric mode for real-time wastewater monitoring and the original current value was regained with a varying recovery time depending on the length of the starvation.
403 citations
TL;DR: Results show that inoculation and enrichment procedures are critical to the initial success of larger-scale systems and better methods will be needed to isolate hydrogen gas produced at the cathode.
Abstract: A pilot-scale (1,000 L) continuous flow microbial electrolysis cell was constructed and tested for current generation and COD removal with winery wastewater. The reactor contained 144 electrode pairs in 24 modules. Enrichment of an exoelectrogenic biofilm required ~60 days, which is longer than typically needed for laboratory reactors. Current generation was enhanced by ensuring adequate organic volatile fatty acid content (VFA/SCOD ≥ 0.5) and by raising the wastewater temperature (31 ± 1°C). Once enriched, SCOD removal (62 ± 20%) was consistent at a hydraulic retention time of 1 day (applied voltage of 0.9 V). Current generation reached a maximum of 7.4 A/m3 by the planned end of the test (after 100 days). Gas production reached a maximum of 0.19 ± 0.04 L/L/day, although most of the product gas was converted to methane (86 ± 6%). In order to increase hydrogen recovery in future tests, better methods will be needed to isolate hydrogen gas produced at the cathode. These results show that inoculation and enrichment procedures are critical to the initial success of larger-scale systems. Acetate amendments, warmer temperatures, and pH control during startup were found to be critical for proper enrichment of exoelectrogenic biofilms and improved reactor performance.
389 citations
TL;DR: The maximal hydrogen production potential by anaerobic bacteria is 1.3 to 2.2 mol-H2/mol-glucose, which is less than 50% of theoretical, and the fatty acid production from the vacuum cultures exhibited approximately the same yield of fatty acids as those of the non-vacuum cultures.
378 citations
TL;DR: In this paper, the membrane separation capacity of a membrane bioreactor allows the retention of most microbial cells in the reactor to maintain a high biomass concentration, resulting in an efficient biological digestion system.
365 citations