Background: Wet coffee processing consists of the removal of the pulp and mucilage
of the coffee cherry. This process generates a large amount of acidic wastewater
which is very aggressive to the environment because of its high content of recalcitrant organic
matter. Therefore, treatment is necessary before discharge to water bodies. Because of
this reason, this study aimed to evaluate the organic matter removal efficiency in an Anaerobic
Baffled Bioreactor (ABR) coupled to a Microfiltration Membrane (MF) system as a new
eco-friendly option in the treatment of wet Coffee Processing Wastewater (CPWW).
Methods:
Two systems (S1 and S2) were evaluated at Hydraulic Retention Times (HRT) of
59 h and 83 h, respectively. Both systems were operated at mesophilic conditions, at a
Transmembrane Pressure (TMP) of 50 kPa during 1800 h.
Results:
The S2 generated higher organic matter removal efficiency, reaching removal values
of turbidity of 98.7%, Chemical Oxygen Demand (COD) of 81%, Total Solids (TS) of
72.6%, Total Suspended Solids (TSS) of 100%, and Total Dissolved Solids (TDS) of 61%,
compared with the S1.
Conclusion:
The S2 represents a new eco-friendly alternative to treat CPWW and reduce its
pollutant effect.
Currently, landfills are the main method used for the final disposal of urban solid waste. The degradation processes that waste goes through in these sites, alongside rainwater that percolates through them, generate highly polluting liquids (leachate). In the treatment of leachate, advanced oxidation processes (AOP) can significantly reduce the concentrations of different pollutants. Due to the high documented potential around AOPs, in this study, the effectiveness of anodic oxidation in the removal of the remaining organic load in leachates pretreated in a biological system was evaluated. Graphite electrodes were used as anode and cathode. The efficiency of anodic oxidation, in terms of the removal of chemical oxygen demand (COD) and color, was evaluated under different current densities (7, 12, 17 and 22 mA/cm 2) and pH values (3, 4.5 and 6). Under the best conditions found (22 mA/cm 2 and pH of 6) and with an oxidation time of 5 hours, a maximum removal of 68% in COD and 91% in color was achieved, which represented a quality in the final effluent of 271 mg/L and 151 Pt-Co in COD and color, respectively. Therefore, considering that graphite is an economic and widely available material, the results obtained show anodic oxidation, with the use of graphite electrodes, as a technically viable alternative as a final purification stage for pretreated leachates.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.