Simultaneous aerobic-anaerobic biodegradation of an industrial effluent of polymeric resins with high phenol concentration at different organic loading rates in a non-conventional UASB type reactor

Abstract

The presence of phenol in the environment is a consequence of both natural actions and anthropogenic contributions, mainly of an agricultural and industrial nature. Its concentration in wastewater ranges from 0.1 to 3,900 mg/L and in some cases from 30,000 to 80,000 mg/L. Among the technologies used for its elimination, are the physicochemical, biological, adsorption, and chemical oxidation processes. For its recovery, there is adsorption, ion exchange, extraction, volatilization, polymerization, electrocoagulation, advanced oxidation and ion exchange. In this research, a new configuration Upflow Anaerobic Sludge Blanket reactor (UASB) was studied to biodegrade the phenol present in an industrial effluent of polymeric resins by varying the organic load rate in 3.2 ± 0.6, 13.9 ± 0.8, 33.5 ± 1.1 and 34.6 ± 0.9 kg COD/m3.d, at two rates of Dissolved Oxygen (DO): 0.78 ± 0.18 mg/L (experiments 1–3) and 1.23 ± 0.02 mg/L (experiment 4), with a Hydraulic Retention Time (HRT) of 0.5 days at 30 ± 0.5 °C. The results showed the best Chemical Oxygen Demand (COD) removal rate and phenol biodegradation (64 and 74%, respectively) at a lower organic load (experiment 1). With a gradual increase in this, during experiments 2 and 3, it decreased by 55.6 and 17%, respectively. However, by increasing the dissolved oxygen rate to 1.23 ± 0.02 mg/L during experiment 4, the phenol biodegradation rate was slightly improved, but not the COD removal rate.