Thesis (Ph. D.)--West Virginia University, 2003. / Title from document title page. Document formatted into pages; contains xi, 153 p. : ill. (some col.), col. maps. Vita. Includes abstract. Includes bibliographical references (p. 136-152).

Thesis (Ph. D.)--West Virginia University, 2003. / Title from document title page. Document formatted into pages; contains xi, 121 p. : ill., maps (some col.). Includes abstract. Includes bibliographical references.

Thesis (Ph. D.)--University of Queensland, 2002. / Includes bibliographical references.

Thesis (M.A.)--Marshall University, 2003. / Title from document title page. Document formatted into pages; contains v, 95 p. Includes bibliographical references (p. 88-93).

Succinic Acid (SA) is an intermediate in the production of fine and commodity chemicals. No commercial SA bioproduction process exists due to process limitations including end product inhibition and high product separation costs, which account for 70% of total production costs. Two-Phase Partitioning Bioreactors (TPPBs) can increase volumetric productivity through in-situ product removal, although SA uptake by polymers requires a pH below the pKA2 of SA (4.2). Sparging CO2 gas into the bioreactor was proposed to temporarily lower the pH of the medium, allowing for SA uptake. At 1atm CO2 sparging lowered the pH of Reverse Osmosis (RO) water to 3.8 but only to 4.75 in medium, requiring the use of H2SO4 and KOH for pH adjustment in subsequent experiments. Polymers were screened for SA uptake and the effect of pH on uptake from 2.2 to 6.2 was also studied. Only Hytrel® 8206 showed non-zero uptake with a partition coefficient for SA of 1.3. Cell cultures of Actinobacillus succinogenes was exposed to pH 4.2 for times from 5 minutes to 4 hours to determine whether cells could grow after low pH exposure. A. succinogenes resumed growth after up to 4 hours of low pH exposure, giving a sufficient time span for SA uptake in the bioreactor. A single-phase run was operated as a benchmark for comparison to the TPPB system which removed SA from the fermentation broth by pH cycling; lowering the pH to 3.8 for uptake, then increasing it to 6.7 to continue bioproduction. Uptake from fermentation broth took 60 minutes, within the time causing no effect on cell growth from low pH exposure. The two-phase run yielded 1.39g/L•h, unchanged compared to the single-phase run which gave 39g/L of SA after 28 hours. Though pH cycling reduced the concentration of SA through polymer uptake, the salts added for pH adjustment hindered further cell growth. The TPPB system demonstrated that SA can be efficiently removed from solution without complex separation methods. Future work will use pressurized vessels to increase the solubility of CO2 and lower the pH of fermentation broth for SA uptake without the need for strong acids. / Thesis (Master, Chemical Engineering) -- Queen's University, 2011-04-18 08:07:51.379

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The success of enhanced biological phosphorus removal depends on the constant availability of volatile fatty acids (VFAs). To reduce costs of purchasing external carbon, waste streams would be a preferred source for nutrient removal. VFAs were shown to vary in the incoming sewage and fermentate from primary sludge (PS). Another available source of organic to generate VFAs is waste activated sludge (WAS). The effect of solids retention time and biomass concentration, as well as the effect of temperature and requirement for mixing on generation of VFA from the fermentation of WAS were investigated. It was found that VFA yields from sludge fermentation increased with SRT. At the longest SRT of 10 days improved biomass degradation resulted in the highest soluble to total COD ratio and the highest VFA yield. WAS fermentation was found highly temperature-dependent. The overall VFA–COD concentration in the non-mixed reactors was much lower than the mixed reactors. The study of fermentation of PS, WAS and a mixture of WAS and PS demonstrated that PS fermentation predictably generated a significantly higher amount of soluble COD than WAS. Co-fermentation of WAS with PS enhanced soluble COD production and increased the release of phosphate and ammonium. Fermentation of combined PS and WAS sludge generated a concentration of phosphate high enough to allow phosphorus recovery as struvite The effect of using glycerol as an external carbon source in biological phosphorus removal was investigated. Using glycerol directly resulted in the failure of the process which maintained enhanced biological phosphorus removal. When glycerol was co-fermented with waste activated sludge, significant VFA production was observed. By 2 | P a g e supplying the system with the VFA-enriched supernatant of the fermentate, biological phosphorus removal was enhanced. It was concluded that, if glycerol was to be used as external carbon source for biological phosphorous removal, the effective approach was to ferment glycerol with waste activated sludge. According to the cost analysis, the economic benefit of WAS fermentation can be demonstrated in three ways: 1) cost saving in external carbon addition; 2) cost saving in sludge handling; 3) revenue from phosphorus. At current condition, the value of the recovered P product is insignificant relative to the cost of chemicals that required for recovery and capital cost of the facilities. However, P recovery becomes important when the sustainability take into account.

No description available.

The success of enhanced biological phosphorus removal depends on the constant availability of volatile fatty acids (VFAs). To reduce costs of purchasing external carbon, waste streams would be a preferred source for nutrient removal. VFAs were shown to vary in the incoming sewage and fermentate from primary sludge (PS). Another available source of organic to generate VFAs is waste activated sludge (WAS). The effect of solids retention time and biomass concentration, as well as the effect of temperature and requirement for mixing on generation of VFA from the fermentation of WAS were investigated. It was found that VFA yields from sludge fermentation increased with SRT. At the longest SRT of 10 days improved biomass degradation resulted in the highest soluble to total COD ratio and the highest VFA yield. WAS fermentation was found highly temperature-dependent. The overall VFA–COD concentration in the non-mixed reactors was much lower than the mixed reactors. The study of fermentation of PS, WAS and a mixture of WAS and PS demonstrated that PS fermentation predictably generated a significantly higher amount of soluble COD than WAS. Co-fermentation of WAS with PS enhanced soluble COD production and increased the release of phosphate and ammonium. Fermentation of combined PS and WAS sludge generated a concentration of phosphate high enough to allow phosphorus recovery as struvite The effect of using glycerol as an external carbon source in biological phosphorus removal was investigated. Using glycerol directly resulted in the failure of the process which maintained enhanced biological phosphorus removal. When glycerol was co-fermented with waste activated sludge, significant VFA production was observed. By 2 | P a g e supplying the system with the VFA-enriched supernatant of the fermentate, biological phosphorus removal was enhanced. It was concluded that, if glycerol was to be used as external carbon source for biological phosphorous removal, the effective approach was to ferment glycerol with waste activated sludge. According to the cost analysis, the economic benefit of WAS fermentation can be demonstrated in three ways: 1) cost saving in external carbon addition; 2) cost saving in sludge handling; 3) revenue from phosphorus. At current condition, the value of the recovered P product is insignificant relative to the cost of chemicals that required for recovery and capital cost of the facilities. However, P recovery becomes important when the sustainability take into account.