Wet Oxidation Lumped Kinetic Model for Wastewater Organic Burden Biodegradability Prediction

Abstract

In many cases, treatment of wastewaters requires a combination of processes that very often includes biological treatment. Wet oxidation (WO) in combination with biotreatment has been successfully used for the treatment of refractory wastes. Therefore, information about the biodegradability of wastewater solutes and particulates after wet oxidation is very important. The present work proposes a model that can describe the oxidation process via organic concentration characteristics such as chemical oxygen demand (COD), biochemical oxygen demand (BOD), and immediately available BOD (IA BOD) and so can allow the prediction of biodegradability (i.e., BOD/COD ratio). The reaction mechanism includes the destruction of nonbiodegradable substances bytwo pathways: oxidation to carbon dioxide and water and oxidation to larger biodegradable compounds with their further degradation to smaller ones measured via IA BOD. The destruction of small biodegradable compounds to end products is also included in the model. The experiments were performed at different temperatures (170-200 degrees C) and partial oxygen pressures (0.5-1.5 MPa) in a batch stainless steel high-pressure autoclave. The model of concentrated thermomechanical pulp circulation water was selected for the experiments. The proposed model correlates with the experimental data well and it is compared with other WO models in the literature.

Wet Oxidation of Process Waters from the Hydrothermal Carbonization of Sewage Sludge

“…As previously shown, two reaction pathways can be distinguished during WO , . One is the direct mineralization of already highly oxidized components, for example via decarboxylation of ketoacids.…”

A practical parametrical characterization of the Fenton and the photo‐Fenton sulfamethazine treatment using semi‐empirical modeling

“…On one hand, the degradation of the SMT contaminant is measured through a lumped parameter such as the concentration of total organic carbon, [TOC], which allows practical and inexpensive monitoring but provides a poor inference capacity in terms of fundamental explanation of the mechanism of the process. These considerations lie also behind previous works28, 29 addressing the modeling of oxidation processes using aggregated parameters such as COD and BOD, instead of TOC. On the other hand, the model developed is intended to overcome the limitations of pure statistical modeling and has been expressed in terms of physically meaningful factors that may be used for quantitatively assessing the performance of the process.…”

Experimental coupling and modelling of wet air oxidation and packed-bed biofilm reactor as an enhanced phenol removal technology

“…It can be optimised in terms of energy consumption (Lefevre et al 2011). Verenich and Kallas (2002) showed that WAO as a pre-treatment could enhance biodegradability of pulp and paper mill effluents from 24 to 89%. Moreover, this process can be economically viable for concentration of some relatively high wastes, due to its high efficiency and short residence time.…”