A model incorporating stripping, sorption and biodegradation as mechanisms for removing organic compounds from wastewaters /
| Main Author: | |
|---|---|
| Other Authors: | , , , |
| Format: | Thesis Book |
| Language: | English |
| Published: |
1989.
|
| Subjects: | |
| Online Access: | Link to OAKTrust copy |
| Abstract: | A model has been developed for removal of multiple organic substrates from water by biodegradation, sorption on biomass, and stripping in countercurrent packed biofilm columns. The model is divided in two components: i) A biofilm model computes steady-state biodegradation and sorption rates, which are based on substrate concentrations at the biofilm-water surface. Biodegradation within the biofilm is expressed by the double-limiting Monod reaction rate, oxygen and biodegradable organic matter being the limiting substrates. The observed rate of sorption is a direct function of detachment rate, and of water-biomass partition coefficient. Biomass detachment is equated to integrated net growth. Model assumptions include homogeneous biofilm, no interaction between organic substrates, and diffusion only in the direction perpendicular to the biofilm-water surface. The model consists of a set of first and second-order ordinary differential equations (ODE) describing material balances for every organic compound, oxygen and biomass. ii) A biostrip model computes removal rates within the biofilm, which are based on bulk concentrations and external mass transfer coefficients for countercurrent packed columns. The stripping rate of strippable compounds is computed based on a water-air transfer coefficient. The model consists of a set of first-order ODE's describing material balances for suspended biomass in water, and for every organic substrate and oxygen in both the water and air phase. Removals for acetate, PCP and toluene were tested in a laboratory-scale countercurrent packed reactor. There was a good agreement between predicted and lab data for the effect of hydraulic load on the reactor's removal efficiency. However, suspended solids production was lower than predicted, indicating that detachment was expressed by both continuous shearing and sloughing. Measured water-air transfer coefficient for toluene, biokinetic parameters for acetate and partition coefficient for PCP were found to be in good agreement with reported values. Biofilm greatly reduces stripping efficiency of the biostrip reactor. |
|---|---|
| Item Description: | Typescript (photocopy). Vita. "Major subject: Civil Engineering." |
| Physical Description: | xiv, 187 leaves : illustrations ; 29 cm |
| Bibliography: | Includes bibliographical references. |