Modeling the Operating Performance of a Drinking Water Biological Aerated Filter and the Formation of Organic Nitrogen.

In this study, simultaneous storage and growth mechanism, as well as the formation processes of organic nitrogen (ON), were both introduced into activated sludge model 3 (ASM3), and ASM3-ON was formed to predict the operation of biofilm treatment processes and the formation of dissolved organic nitrogen (DON). ASM3-ON was applied to a lab-scale biological aerated filter (BAF) for water supply. During the simulation, the sensitivities of chemical oxygen demand (COD), ammonia nitrogen (NH-N), nitrate nitrogen (NO-N), and DON to the stoichiometric and kinetic coefficients in the model were analyzed first by the Sobol method.

Spectral characterization of the effect of gas-water ratio on dissolved organic nitrogen variation along a drinking water biological aerated filter.

To improve the understanding of dissolved organic nitrogen (DON) variation characteristics in a biological aerated filter (BAF) used for drinking water treatment, this study investigated the effects of gas-water ratios (0, 0.5:1, 2:1, and 10:1), a controlling factor of BAF operation, on DON characteristics. The dissolved organic carbon (DOC) removal efficiency in the BAF was consistent with DON concentration and increased as the gas-water ratio increased to a certain point, above which the increase gradually decreased.

[Improvement of "scatter degree" method and its application in evaluating river ecosystem health].

"Scatter degree" method is generally blamed for not capable of reflecting the subjective information of evaluator in comprehensive evaluation and for the complexity, uncertainty, and variety of the factors affecting river ecosystem health. In this paper, the "scatter degree" method was improved and applied to comprehensively evaluate the ecosystem health status of the upstream, midstream, and downstream of Beiyunhe River which flowed through Beijing and Tianjing. The ecosystem health value of upstream, midstream, and downstream was evaluated as 0.