SciELO - Scientific Electronic Library Online

 
vol.44 issue1Assessing the clogging and permeability of degrading packed bed reactorsEvaluation of the effectiveness of the National Benchmarking Initiative (NBI) in improving the productivity of water services authorities in South Africa author indexsubject indexarticles search
Home Pagealphabetic serial listing  

Services on Demand

Article

Indicators

Related links

  • On index processCited by Google
  • On index processSimilars in Google

Share


Water SA

On-line version ISSN 1816-7950
Print version ISSN 0378-4738

Abstract

HERNANDEZ, JE  and  EDYVEAN, RGJ. Toxicity and biodegradability of caffeic acid in anaerobic digesting sludge. Water SA [online]. 2018, vol.44, n.1, pp.27-36. ISSN 1816-7950.  http://dx.doi.org/10.4314/wsa.v44i1.04.

Caffeic acid in waste comes from a variety of industries, and its disposal is likely to increase due to emerging processes such as graphene production and use in healthcare products. The current sustainable option to treat waste caffeic acid and prevent its natural transformation in soil to greenhouse gases, is anaerobic digestion. However, little is known about the toxic and inhibitory effects of caffeic acid on biogas production as well as its ultimate anaerobic biodegradability; or about the reactive-adsorptive processes taking place with caffeic acid in sludge, metabolic intermediates, thermodynamic limitations and the effects on extracellular polymeric substances (EPS). Standard methods revealed that 80% of biogas production (EC80) from a readily digestible biomass was inhibited at 389 mg caffeic acid·g-1 VSS. Up to 52% of caffeic acid was biodegraded. β-oxidation and reductive dehydroxylation were the initial activation reactions transforming caffeic acid into typical polyphenol structural units (protocatechuic acid and 4HBA). Adsorption of caffeic acid (53.3% and 28.6%) to the sludge occurred even at inhibitory concentrations. The EPS structure remained unchanged regardless of the increase in concentration of caffeic acid. Reasonable concentrations of caffeic acid could be co-digested with a similar readily digestible biomass with an expected reduction in biogas production. It is feasible to treat waste caffeic acid by anaerobic digestion and adsorption of its derivates, in order to reduce the contribution to global warming and to protect the environment.

Keywords : anaerobes; anaerobic digestion; biogas; biomass; caffeic acid; graphene; inhibition; polyphenols; renewable energy; toxicity; wastewater.

        · text in English     · English ( pdf )

 

Creative Commons License All the contents of this journal, except where otherwise noted, is licensed under a Creative Commons Attribution License