High suspended solids removal of Indian drain water with a down-scaled Dissolved Air Flotation (DAF) for water recovery. Assessing water-type dependence on process control variables

The Barapullah drain crosses through New Delhi, India, and transports millions of cubic meters stormwater, municipal sewage industrial to the Yamuna River. Seasonal variations ambiguous annual discharges cause 20-fold fluctuations in hydraulic flows, pollutants type concentration. Furthermore, Delhi is among most densely populated areas on planet, with limited surface area high water stress. Dissolved Air Flotation (DAF) units are known be highly compact, robust, an efficient suspended solids separation technology that enables further recovery a treatment train. Thus, down-scaled column DAF was designed used determine total removal efficiencies, under different influent conditions. Three influents resemble seasonal composition, fourth imitates feed when located after anaerobic bioreactor were tested. A 60 batch experiments completed assess seven independent control variables for operation, which Total Suspended Solids (TSS), pH, temperature, particles residence time, white pressure, coagulants flocculants concentration, coagulation flocculation time. Results showed could steered from low comparable full-scale systems. Maximum TSS varied between 92 96%. effect statistical relevance performance measured efficiencies depended type. All variables, except temperature had significant p-value below 0.1, at least one influent. Pressure positive efficiency, due its importance bubble formation. Moreover, system efficiency spherical shapes, diameters 10 µm. Based all tested influents, studied efficiently remove drain. unit robustness flows pollutant concentrations, small footprint, show suitability as part train recovery, areas.