Combined ozonation and biofilm treatment for reuse of papermill wastewaters.
A process of advanced oxidation treatment discussed here has been developed in the last seven years. A technical plant for treatment of paper mill wastewater started operation in 1999. Advanced oxidation treatment is defined here as a combination of chemical and biochemical oxidation applied to a completely biodegraded effluent. The process is a combination of ozonation with following biodegradation in a biofilm reactor. The combination makes use of the effect of partial oxidation in which with reduced use of expensive chemical oxidants persistent COD becomes biodegradable. A far-reaching elimination of AOX, colour and other disturbing substances like complexing agents is achieved simultaneously. The partially oxidized compounds, now biodegradable, are eliminated in a following biofilm reactor. Using single-stage systems, COD elimination rates of up to 60% are achieved with 0.4 to 1.0 g ozone per g COD eliminated in the combined process. With a two-stage system COD elimination of 85% with 0.65 g/g has been achieved in pilot tests. The quality of the treated effluent suits fresh water requirements for most types of paper production, so that either a total closure of the water circuits or - due to increasing concentrations of electrolytes, which are not eliminated by this process - a substantial closure to about 20% of the original amount of fresh water can be achieved.
Möbius
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CM Consult Dr. Christian H. Möbius & Partner, Muesmannstr. 15 g, DE-86199 Augsburg, Germany. cm@cm-consult.de
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D018441:Biofilms; D019149:Bioreactors; D003247:Conservation of Natural Resources; D007220:Industrial Waste; D010083:Oxidants, Photochemical / Q000737:chemistry*; D010084:Oxidation-Reduction; D010126:Ozone / Q000737:chemistry*; D010209:Paper; D014865:Waste Disposal, Fluid / Q000379:methods*; D018508:Water Purification / Q000379:methods*
D007220:Industrial Waste; D010083:Oxidants, Photochemical; D010126:Ozone