Reuse of Wastewater Streams in the P & P Industry Using a Physico-Chemical Treatment Process, 1999 Environmental Conference Proceedings

Nathalie Swinnen & Karl Heinz Gregor

SOLVAY S.A.

Annie Renders

SOLVAY INTEROX S.A.

The increasing demand of the authorities for environmental protection and also cost savings have led many industries (food, textile, P&P and others) to reduce fresh water consumption. To limit fresh water intake by the reuse of effluents, cost effective and technically feasible processes are required to treat, at least partially, the effluent streams. An end-of-pipe treatment for the total effluent seems not applicable because it creates problems, in respect to high volume and dilution, mixing of biodegradable with non-biodegradable effluents, and so on. In this study, the treatment of non-biodegradable or even toxic effluents with high Chemical Oxygen Demand (COD), generated in a debarking process is evaluated.

Since the mid-70’s the development of Advanced Oxidation Technologies (AOT’s) which lead to the production of a strong oxidative species, the hydroxyl radical (HO•), are studied in response to the need of wastewater treatments. Many of the AOT’s are based on the use of hydrogen peroxide (H2O2) as a key chemical to generate, in combination with activators, the hydroxyl radical. Activators like ultrasounds, UV-light, ozone and catalysts are reviewed in this paper as well as the development of a new process based on the Fenton reaction, FSR PROCESS ® (Fenton Sludge Recycling). This patented FSR PROCESS ® uses iron salts as catalyst for the oxidation of the organic compounds contributing to the effluent COD. The catalyst is separated from the treated wastewater and recycled after regeneration in an electrochemical step.

The treatment of the debarking wastewater from a Kraft pulp mill has been performed. This refractory and poorly biodegradable effluent with a high COD was treated with the Fenton reaction. Experimental results show a significant reduction of the COD that would allow the reuse of the water thus offering the possibility to save fresh water and therefore costs. The high efficiency of the Fenton reaction points out the feasibility of FSR PROCESS ® .