Mixing characteristics and whey wastewater treatment of a novel moving anaerobic biofilm reactor

Treatment of Cheese Whey Wastewater Using an Expanded Granular Sludge Bed (EGSB) Bioreactor with Biomethane Production

Cheese whey wastewater (CWW) is the major by-product of the dairy industry. CWW is produced in large quantities, has varied characteristics and is usually disposed of. The disposal of CWW causes a negative impact on the environment of different agroindustrial areas due to the physic-chemical composition that significantly increases its high organic load and nutrients. For this reason, the aim of this work was to carry out an evaluation of the anaerobic treatability of an Expanded Granular Sludge Bed (EGSB) bioreactor as a new sustainable alternative for treatment of these effluents with bioenergy production. In this study, the bioreactor was operated under stable conditions (i.e., buffer index of 0.23 ± 0.1, pH 7.22 ± 0.4 and temperature 26.6 ± 1.4 °C) for 201 days. During evaluation the hydraulic retention time (HRT) was 6 and 8 days, and it was buffered with NaHCO3. At these conditions, the COD removal rate and biochemical methane potential (BMP) were 90, 92%; and 334, 328 mLCH4/gCOD, respectively. The evidence found in this study highlighted that the CWW is a viable substrate to be treated in the EGSB bioreactor as long as it keeps buffered. Furthermore, the process to treat the CWW in an EGSB bioreactor can be a sustainable alternative to simultaneously solve the environmental pollution that this agro-industry confronts and produce renewable and environmentally-friendly bioenergy.

Modelling biofilm anaerobic reactor with effluent from hydrolytic/acidogenic reactor as substrate

This work presents modelling of an anaerobic biofilm reactor using ceramic bricks as support. The results were compared with the experimental data. It was observed that the substrate concentration curves showed the same tendency. The methane formation curves showed significant differences. The substrate removal efficiency was 83%. In the steady state, the experimental data were higher than the model, from the result the substrate degrading bacteria grew enough to reach biofilm and that the effect of the shear stress was more significant as the biofilm increased in thickness. To the methane production, the model in steady state reached a maximum value of 0.56 m³ CH₄/m³ *d and the experimental data reached 0.42 (m³ CH₄/m³ * d). The biofilm thickness calculated by the model was 14 μm.

General Characteristics and Treatment Possibilities of Dairy Wastewater - A Review

The milk processing industry is one of the world's staple industries, thus the treatment possibilities of dairy effluents have been attracting more and more attention. The purpose of the paper is to review contemporary research on dairy wastewater. The origin, categories, as well as liquid by-products and general indicators of real dairy wastewater are described. Different procedures applied for dairy wastewater management are summarised. Attention is focused on in-factory treatment technologies with the emphasis on biological processes. Aerobic and anaerobic methods with both their advantages and disadvantages are discussed in detail. Consecutive anaerobic and aerobic systems are analysed, too. Finally, future research niches are identified.

Cheese whey wastewater: characterization and treatment

Cheese whey wastewater (CWW) is a strong organic and saline effluent whose characterization and treatment have not been sufficiently addressed. CWW composition is highly variable due to raw milk used, the fraction of non valorized cheese whey and the amount of cleaning water used. Cheese whey wastewater generation is roughly four times the volume of processed milk. This research tries to conduct an exhaustive compilation of CWW characterization and a comparative study between the different features of CWW, cheese whey (CW), second cheese whey (SCW) and dairy industry effluents. Different CWW existing treatments have also been critically analyzed. The advantages and drawbacks in aerobic/anaerobic processes have been evaluated. The benefits of physicochemical pre-stages (i.e. precipitation, coagulation-flocculation) in biological aerobic systems are assessed. Pre-treatments based on coagulation or basic precipitation might allow the application of aerobic biodegradation treatments with no dilution requirements. Chemical precipitation with lime or NaOH produces a clean wastewater and a sludge rich in organic matter, N and P. Their use in agriculture may lead to the implementation of Zero discharge systems.

Performance and kinetic evaluation of anaerobic moving bed biofilm reactor for treating milk permeate from dairy industry

High strength milk permeate derived from ultra-filtration based cheese making process was treated in an anaerobic moving bed biofilm reactor (AMBBR) under mesophilic (35 degrees C) condition. Total chemical oxygen demand (TCOD) removal efficiencies of 86.3-73.2% were achieved at organic loading rates (OLR) of 2.0-20.0 g TCOD L(-1) d(-1). A mass balance model gave values of methane yield coefficient (Y(G/S)) and cell maintenance coefficient (k(m)) of 0.341 L CH(4) g(-1) TCOD(removed) and 0.1808 g TCOD(removed) g(-1) VSS d(-1), respectively. The maximum substrate utilization rate U(max) was determined as 89.3 g TCOD L(-1) d(-1) by a modified Stover-Kincannon model. Volumetric methane production rates (VMPR) were shown to correlate with the biodegradable TCOD concentration through a Michaelis-Menten type equation. Moreover, based on VMPR and OLR removed from the reactor, the sludge production yield was determined as 0.0794 g VSS g(-1) TCOD(removed).