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KINETIC PARAMETERS SENSITIVITY ANALYSIS OF THE CALUMET WATER RECLAMATION PLANT USING GPS-X
Title
KINETIC PARAMETERS SENSITIVITY ANALYSIS OF THE CALUMET WATER RECLAMATION PLANT USING GPS-X
Creator
Mao, Xiangzhou
Date
2015, 2015-07
Description
It is an important objective to find equilibrium between cost and effluent water quality at the Calumet water reclamation plants (WRP)....
Show moreIt is an important objective to find equilibrium between cost and effluent water quality at the Calumet water reclamation plants (WRP). Kinetic parameters of activated sludge process have significant influence on effluent water quality. In this study, based on a simulation model, sensitivity analysis methods were used to assess the effects of six kinetic parameters on dissolved oxygen, carbonaceous biochemical oxygen demand (CBOD5), and effluent ammonia concentration. According to the values of kinetic parameter, two cases: ±10% perturbation of the typical default value and full parameter range were studied. Results presented that main effects have important effects on the output variables. Heterotrophic maximum specific growth rate, heterotrophic decay rate, autotrophic maximum specific growth rate, autotrophic decay rate, and maximum specific hydrolysis rate have relatively significant sensitivity. In addition, the influences of the interactions among kinetic parameters are discussed. Keys words: Kinetic parameters; sensitivity analysis; water reclamation plants; dissolved oxygen; CBOD5; ammonia
M.S. in Environmental Engineering, July 2015
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CHANGES OF BACTERIAL SPECIES AND HEME PROTEIN LEVEL IN ACTIVATED SLUDGE COMMUNITIES ACCLIMATED TO LOW AERATION
Title
CHANGES OF BACTERIAL SPECIES AND HEME PROTEIN LEVEL IN ACTIVATED SLUDGE COMMUNITIES ACCLIMATED TO LOW AERATION
Creator
Li, Hainan
Date
2016, 2016-05
Description
Increasing oxygen utilization of activated sludge under low dissolved oxygen (DO) conditions can lead to energy savings in wastewater...
Show moreIncreasing oxygen utilization of activated sludge under low dissolved oxygen (DO) conditions can lead to energy savings in wastewater treatment systems. Adaptation of sludge communities to low oxygen conditions may be facilitated by increased expression of heme proteins. One way to assess heme protein expression in sludge is to analyze the species present in the sludge community during the adaptation process. In the work reported here, growth of a sludge culture adapted by Kunkel to low aeration for 48 weekly passages was continued for an additional 26 passages (182 days). The activated sludge was cultured in synthetic wastewater under low DO conditions. Temperature, dissolved oxygen, and specific oxygen uptake rates (SOUR) were measured at the end of each weekly passage. The community structures of passages 50, 53 and 65 were determined by 16S rDNA cloning techniques. The type of heme present was identified using the pyridine hemochromogen method. The SOUR values measured increased slightly in the first part of the experiment, when the culture DO was very low, but then decreased in the latter part of the experiment, when the culture DO increased. The community structure diversity in passage 50 in Kunkel’s study and passage 50 from this work are totally different in terms of species present, even though the two cultures were both derived from Kunkel’s passage 48 and were grown under conditions which were matched as closely as possible for two additional passages. This indicates that the community structure is highly sensitive to small changes in growth conditions. From the point of view of types of hemoglobin (Hb), the community became more diverse by passage 53, containing all three types of truncated Hb (trHbN, trHbO, and trHbP), possibly due to the need for NO scavenging and oxygen transfer enhancement. The proportion of cells that synthesize truncated Hb decreased slightly through passages 50 to 53 to 65. The percentage of cells that encode FlavoHbs decreased from 84 % to 50 % by passage 65. Overall there was an increase in Hb expression from passage 50 to passage 65. Heme b expression in the sludge culture was confirmed. Successful adaptation of the sludge culture to low DO conditions via enhancement of oxygen uptake was not obvious in this study. Yet the overall tendencies of SOUR and Hb expression suggest that it is possible to acquire a culture more efficient in oxygen uptake if a stable low aerobic environment can be maintained for an extended period.
M.S. in Biology, May 2016
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