Novel wastewater pre-treatment technology for pulp and paper mills, with particular emphasis on colour removal

摘要

The DELMAR technology is a cost-efficient and highly effective chemical process for the pretreatment of industrial wastewaters containing recalcitrant dissolved organic and inorganic pollutants amenable to chemical reduction and large concentrations of solids. The process is based on the redox efficiency of a bimetallic alloy system capable of "softening" complex and oxidised organic pollutants, removing particulate and colloidal solids in the form of sludge, removing large fractions of environmentally targeted pollutants and increasing the overall biodegradability of wastewater streams. The process is particularly effective in targeting the chromophore bonds of the wastewater composite molecules resulting into a significantly more transparent effluent. As a result, the system is ideal for the pre-treatment of industrial effluents, such as those from pulp and paper mills, which may be subsequently treated more fully, more effectively and at lower cost by conventional biological treatment processes. The DELMAR technology is highly versatile in its application. It may be applied as a stand-alone treatment to allow partial effluent reuse, overcome problems associated with the acceptance of effluent discharge into local municipal wastewater treatment works and minimise the cost associated with it. It may also be incorporated as a pre-treatment into full treatment schemes in order to improve the efficiency of downstream treatment, and decrease the required capital expenditure and operating cost. The present paper discusses the main features/advantages of the technology and presents results from a series of case studies from pulp and paper mills around the world, where the effectiveness of the treatment was demonstrated with laboratory and on-site pilot trials.