The treatment of cheese whey wastewater by sequential anaerobic and aerobic steps in a single digester at pilot scale

Abstract

The treatment of cheese whey wastewater by sequential anaerobic and aerobic steps in a single digester at pilot scale Frigon, J.-C.; Breton, J.; Bruneau, T.; Moletta, R.; Guiot, S. R. The treatment of reconstituted whey wastewater was performed in a 400 L digester at 20°C, with an anaerobic digestion step, followed by a step of aerobic treatment at low oxygen concentration in the same digester. In a first set of 48 cycles, total cycle time (T C ) of 2, 3 and 4 days were tested at varying organic loading rates (OLR). The COD removal reached 89 ± 4, 97 ± 3 and 98 ± 2% at T C of 2, 3 and 4 days and OLR of 0.56, 1.04 and 0.78 gCOD L À1 d À1 , respectively. The activity of the biomass decreased for the methanogenic population, while increasing by 400% for the acidogens, demonstrating a displacement in the predominant trophic group in the biomass bed. A second set of 16 cycles was performed with higher soluble oxygen concentration in the bulk liquid (0.5 mg L À1 ) during the aerobic treatment at a T C of 2 days and an OLR of 1.55 gCOD L À1 d À1 , with a soluble COD removal of 88 ± 3%. The biomass specific activities showed a compartmentalization of the trophic group with methanogenic activity maintained in the biomass bed and a high acidogenic activity in the suspended flocs.Crown

Biotechnological Utilization with a Focus on Anaerobic Treatment of Cheese Whey: Current Status and Prospects

“…It is observed that Frigon et al [83] achieved the highest COD removal at the shortest HRT and at psychrophilic conditions (20 °C), in a single digester of anaerobic and aerobic treatment. Therefore the use of integrated reactors (anaerobic/aerobic digestion) with stacked configuration in treating high strength industrial wastewaters is advantageous in terms of minimal space requirements, low capital cost and COD removal efficiencies obtained.…”

“…The anaerobic degradation of the main fraction of organic matter and then the aerobic treatment of the partially treated wastewaters, in order to reduce the final organic load of the effluent and to fulfill the discharge requirements [83]. The aerobic treatment step can be provided by aerated ponds [98,117], or aerobic jet loop membrane reactors [3].…”

“…The SBR operated at cycles of 48 h, with different levels of aeration after the initial incubation of 30 h. By adding 54 mg O 2 /g COD influent over 16 h achieved the best performance of the system, with soluble COD removal of 99% and a residual soluble COD of 104 ± 22 mg/L. Recently, the same research group [83], in order to reduce the cost of the investment, evaluated in a single digester the potential of psychrophilic AD, for the most of the biodegradable materials, followed by aerobic polishing sequence. The concept of coupling anaerobic and aerobic steps inside one digester is promising.…”

Dairy Wastewaters – General Characteristics and Treatment Possibilities – A Review

“…In accordance with specifi c biomass activity, trophic differentiation can be seen in the system: methanogens predominantly live at the bott om of the bulk liquid, while acidogens inhabit suspended fl ocs. When the soluble O 2 rose to 0.5 mg/L during the aerobic phase, the COD was reduced to (88±3) % in a 2-day total cycle time at 1.55 kg/ (m 3 ·day) (111).…”

Biogas production by the anaerobic digestion of whey

“…It shows high biodegradability and relatively high alkalinity. Cheese whey accounts for 70% to 75% of the lactose present in the milk and 10% to 15% of soluble proteins, what results in chemical oxygen demand (COD) between 50 and 70 g L -1 (Frigon et al, 2009). …”