Electrochemical treatment of industrial wastewater

The removal or breakdown of org. compds. from wastewater is an important and integral part of any industrial chem. process. Described here is the electrochem. treatment (or pretreatment prior to biol. treatment) of industrial wastewater (BASF wastewater) contg. ter-butanol, a difficult biodegradable compd. Expts. were 1st carried out using model wastewater systems followed by industrial wastewater samples provided by a BASF Polymer Dispersion prodn. plant in Ludwigshafen. The main results can be summarized in the following points: (a) study of synthetic (or model) wastewater. The electrochem. oxidn. of ter-butanol at B doped diamond (BDD) electrode is mass transport controlled. It can be achieved with a 100% current efficiency (in the absence of mass transport limitations). Other orgs. compds. in the synthetic wastewater (e.g., acetone, methylacrylate, n-butanol) behave in a similar way. The current efficiency depends only on the COD and it is independent of the nature of org. components in wastewater. (b) Investigation of a BASF prodn. plant wastewater sample acetone and n-butanol are initially oxidized much faster than ter-butanol. However, when they reach the ter-butanol concn., all 3 components (acetone, n-butanol, ter-butanol) decay simultaneously with the same rate. It was found that by operating at the limiting current throughout the treatment process (monitoring the c.d.), the specific energy consumption for the electrochem. treatment can be strongly decreased to .apprx.22 KWh/Kg COD. During long-term electrolysis, electrode fouling by the formation of polymeric materials was obsd. [on SciFinder (R)]