摘要:

Volatilization of selected organic compounds, with Henry's law constant larger than 10−3atm‐m3/mole, from water under turbulent conditions has been studied. Surface area:volume ratio and water‐bulk turbulent intensity were the two major parameters that varied in the experiments. A model based on idealized surface renewal process is proposed. Based on this model, an equation incorporating the surface area:volume ratio and turbulent intensity (expressed in terms of the velocity gradient,G) is derived by solving appropriate mass‐transfer differential equations. The derived model has been calibrated and verified with the experimental results. Both the theoretical model and the experimental results confirm that the volatilization of high‐volatility compounds from water into air follows first‐order kinetics with respect to the chemical concentration in water‐bulk phase. The volatilization rate constant is found to be proportional to the surface area:volume ratio. It is also observed that the turbulent intensity in the water phase is an important parameter in controlling the volatilization of chemicals from the water.

ISSN:1061-4303    

DOI:10.2175/106143095X131240

出版商:Water Environment Federation    

年代:1995

数据来源: WILEY

摘要:

Serum bottle experiments were conducted to investigate the roles that activated carbon and two ion‐exchange resins performed as support material in methanogenic phenol‐degrading cultures. The consortium associated with activated carbon was able to degrade phenol that had been adsorbed to the carbon, demonstrating bioregeneration. Supernatant samples withdrawn from these cultures over a 90‐day period contained an active phenol‐degrading population, indicating that the colonized‐activated carbon continuously shed significant amounts of active biomass. The cation‐exchange resin did not serve as a suitable support material for microbial colonization. The anion‐exchange resin possessed the largest pore volume and sheltered surface area accessible to a microbial population. The phenol‐degrading activity of biomass associated with this resin continued to increase throughout the 85‐day incubation period. Supernatant withdrawn from these cultures was less efficient at removing phenol than the supernatant from the activated carbon‐containing cultures, suggesting that the consortium was still growing and being retained on the resin.

ISSN:1061-4303    

DOI:10.2175/106143095X131259

出版商:Water Environment Federation    

年代:1995

数据来源: WILEY

摘要:

Dissolved free amino acids (DFAA) and dissolved combined amino acids (DCAA, e.g., discrete dissolved polypeptides and proteins as well as amino acids, peptides, and proteins adsorbed to humic material) were measured in unconcentrated domestic wastewater at a detection limit of 10 to 100 nM (coefficient of variation ≤0.10 at 100 nM) using precolumnortho‐phthaldialdehyde derivatization, reverse‐phase high performance liquid chromatography separation, and fluorometric detection. Wastewaters were sampled at three types of wastewater treatment plants: trickling filter, conventional activated sludge, and pure‐oxygen activated sludge. Raw wastewaters contained the largest concentrations (58μM) of dissolved total amino acids (DTAA) with 7% as DFAA. The DTAA were between 28 and 40μM in primary clarifier effluents with 7% to 29% as DFAA. Removal percentages during biological treatment were>70% for DFAA and 23% to 79% for DCAA. Molecular weight separations indicated that most dissolved organic carbon (DOC) (>68%) in the trickling filter influent had small molecular weights (10 000 AMU). The DTAA were a small fraction (8% to 13%) of DOC in both influent and effluent samples.

ISSN:1061-4303    

DOI:10.2175/106143095X131268

出版商:Water Environment Federation    

年代:1995

数据来源: WILEY

ISSN:1061-4303    

DOI:10.1002/j.1554-7531.1995.tb00151.x

出版商:Water Environment Federation    

年代:1995

数据来源: WILEY

ISSN:1061-4303    

DOI:10.1002/j.1554-7531.1995.tb00152.x

出版商:Water Environment Federation    

年代:1995

数据来源: WILEY