Characterization and selection of the appropriate treatment for a food industry wastewater: a case study

The aim of the study was to define the appropriate treatment for a food wastewater (800 m3 d-1) in compliance with Italian regulations (D.Lgs. 152/06), minimizing discharge rates and taking into account site-specific and industry-specific constrains (minimisation of odour emission; easy and flexible operation; minimisation of the treatment plant footprint). The methodological approach consisted of (1) identification of relevant macro-pollutants and characterization of the raw and pre-treated wastewater (pre-treatments by chemical conditioning and air flotation). Then, (2) BMP (Biochemical Methane Potential) assays and (3) respirometric techniques were employed to estimate the biodegradable COD (bCOD) both in anaerobic and aerobic conditions. Based on biological treatability results (bCODanaerobic~60%, bCODaerobic~90%) and above mentioned constrains, the aerobic treatment was selected (4). Then, pilot-scale trials (5) showed effluent COD (80+-19.0 mg L-1) always lower the limit fixed for discharge into surface water by Italian regulations. On the basis of lab and pilot data, (6) the aerobic biological treatment was implemented at the full-scale adopting the Double Treat® technology