Assessment of Dissolved Air Flotation System for Wastewater Treatment in a Paper Industry

Abstract

The paper and cardboard industry has a high dependence on the proper use and wastewater treatment. Water is used in all production phases from the preparation and transformation of raw material to the dilution process in paper machine. The above industrial conditions require special attention to reduce the costs related with water and energy consumption in processes such as paper drying. The main objective of this paper is to evaluate the efficiency of dissolved air flotation (DAF) system in a wastewater plant of a paper industry. This industry manufactures cardboard, where corrugated and liner papers are produced. A comparative analysis is performed between two flocculants (Andifloc - FA and Nalco 68530 - FN) using the following water quality parameters: total suspended solids (TSS), electrical conductivity, and chemical oxygen demand (COD). On average, findings obtained for the FN flocculant displayed that TSS concentration in treated water decreased by 48.1% compared with the FA flocculant. Efficiency in the DAF system increased on average by 3.64%, and efficiencies of up to 97.6% were also observed for TSS removal. The findings also showed a decrease in COD concentration during the evaluation of FN flocculant. An average decrease of 16.2% in COD concentration during FN flocculant use was observed.