Applying real-time pollution control to reduce chemical costs and energy usage for DAF

Dissolved air flotation (DAF) has been successfully applied as wastewater pre-treatment for many years. To guarantee the effluent quality; chemical dosage and aeration are set to deal with the peak loads of TSS and COD. A special developed i-DOSE system based on a TOC measurement for heavy polluted wastewater in combination with real time feed forward control showed that chemical dose for coagulation and flocculation can be reduced and optimized. The i-DOSE system has been tested and incorporated into the new ‘Intelligent DAF’ which reduces the chemical consumption (approximately 25%) and counters the main drawback of higher energy requirement by adjusting the aeration pressure according to the amount of solids in the incoming wastewater. The implementation of the ‘i-DOSE’ system generally results in a ROI of 1-2 years, depending on the amount of treated wastewater. The results shows that i-DOSE can reduce yearly chemical and energy costs up to 25 % and in combination with the state-of-the-art ‘i-DAF achieve high removal efficiencies for pre-treatment of industrial wastewaters.