Coupled photochemical-biological system to treat biorecalcitrant wastewaters

Author

Bacardit Peñarroya, Jordi

Director

Chamarro Aguilera, Esther

Esplugas Vidal, Santiago

Date of defense

2007-07-06

ISBN

9788469091388

Legal Deposit

B.53063-2007



Department/Institute

Universitat de Barcelona. Departament d'Enginyeria Química i Metal·lúrgia

Abstract

Advanced Oxidation Processes (AOPs) are suitable for achieving the complete mineralization of organic pollutants in wastewaters, since they are based on the generation of a powerful non-selective chemical oxidant. A major drawback of AOPs is that they involve high operating costs if high levels of mineralization are endeavoured. Integration of an AOP with a biological treatment has demonstrated to be a suitable alternative, since it combines the capacity of the AOP, in this case Photo-Fenton, to enhance biodegradability, with a biological treatment such as a Sequencing Batch Biofilter Reactor (SBBR), which operating costs are lower.<br/><br/>Photo-Fenton (Ph-F) process is carried out by irradiating the system with ultraviolet (UV) and/or visible (Vis) light. In Fenton processes, by combination of hydrogen peroxide (H2O2) as a reagent and iron ions (Fe2+ for example) as catalyst in acid medium, highly oxidant species are generated.<br/><br/>According to the results, most of the studied parameters may be written as a function of [H2O2]0, which means that temperature and [Fe2+]0 do not affect significantly the results. Moreover, a subsequent scale-up of the process shows that degradation follow very similar tendencies and shows similar results.<br/><br/>It has been observed that the efficiency of oxidation follows a tendency directly related to the amount of H2O2 applied. An innovative description of the process is their modelling regarding the evolution of COD and BOD5 over the oxidation process or depending on the amount of H2O2 applied. The models show good fitting properties, and they appear to be a good basis for more precise modelling of the system.<br/><br/>Regarding the integration of both processes, the best operating conditions consists of first treating the solution by Ph-F with 500 mg.L-1 of [H2O2]0 and 10 mg.L-1 of [Fe2+]0 at 27 ºC. The resulting product is then treated in the SBBR for 8 hours of time. More than 90 % of mineralization is achieved. The bioreactor show high resistance when is exposed to toxic shock load. Concerning control possibilities, monitoring the Oxygen Uptake Rate (OUR) by in-situ respirometry is suggested to be a good parameter, since it is a direct measurement of bacterial activity.

Keywords

Processos d'Oxidació Avançada (POA); Compostos orgànics no-biodegradables; Residus industrials; Tractament d'aigües residuals

Subjects

54 - Química

Knowledge Area

Ciències Experimentals i Matemàtiques

Documents

01.JBP_abstract_and_index.pdf

162.7Kb

02.JBP_Introduction_and_Methods.pdf

1.067Mb

03.JBP_Results_and_Conclusions.pdf

3.239Mb

04.JBP_References_and_lists.pdf

212.9Kb

05.JBP_Summary_in_Catalan.pdf

182.4Kb

 

Rights

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