Treatment of olive oil mill wastewater by a pulsed high‐voltage discharge process; process optimization and combination with Fe⁺² and H₂O₂

Abstract

BACKGROUND: Olive oil mill wastewaters (OOMW) have caused major environmental problems because of the high organic load, high total suspended solids, high inert chemical oxygen demand (COD), low pH, a characteristic odour, its dark colour and toxicity to plants. A pulsed high-voltage discharge (PHVD) process was developed as a novel alternative to advanced oxidation processes for effective treatment of OOMW. RESULTS:The ability of a PHVD process, after acid cracking, to treat OOMW, was investigated. For a PHVD treatment time of 60 min the chemical oxygen demand (COD), total organic carbon (TOC), phenol, and colour removal efficiencies were 21, 31, 23, and 32%, respectively. Following the addition of 63 mmol L −1 H 2 O 2 , the COD, TOC, phenol, and colour removal efficiencies reached 72, 55, 74, and 82%, respectively, for the same treatment time. When 0.37 mmol L −1 Fe 2+ (but no H 2 O 2 ) was added, the COD, TOC, phenol, and colour removal efficiencies were 74, 54, 79, and 72%, respectively. CONCLUSION: PHVD can be used to effectively treat OOMW, using a combination of physical and chemical effects initiated by the electrical discharge into the water.Pilot-scale pulsed high-voltage discharge system A diagram of the PHVD system is shown in Fig. 1. A high-voltage power supply with two rotating spark-gap switches was used to generate the high-voltage pulses. A series of diodes was used to convert alternating current (AC) to direct current (DC). A high-voltage power supply provided a peak voltage in the range 0-24 kV and pulse frequency in the range 0-50 Hz. Four stainless steel 1 mm i.d. needles were inserted into the reactor, from

Effects of High Voltage Electrical Discharge Plasma on Olive Mill Wastewater Treatment

“…Ibrahimoglu and Yilmazoglu [8] reported a 99.3% reduction of COD, and color reduced by 99.2% in OMWW treated with DC arc plasma. Pulsed high-voltage discharge plasma resulted in 72% COD and 74% phenol degradations with the addition of H 2 O 2 , and 74% COD and 79% phenol degradation with the addition of ferrous ions from OMWW [9].…”

“…A promising method for OMWW degradation is plasma technology, mainly because of environmental compatibility and high removal efficiency. However, there is little information on the use of plasma in OMWW treatment [8,9]. Ibrahimoglu and Yilmazoglu [8] treated OMWW with the DC arc plasma method and reported that the rates of COD (chemical oxygen demand) and BOD (biological oxygen demand) of OMWW decreased by 94.42% and 95.37%, respectively, with a color removal rate of 99.2%.…”

“…Ibrahimoglu and Yilmazoglu [8] treated OMWW with the DC arc plasma method and reported that the rates of COD (chemical oxygen demand) and BOD (biological oxygen demand) of OMWW decreased by 94.42% and 95.37%, respectively, with a color removal rate of 99.2%. Kuşçu and Eke [9] reported that treatment of OMWW with pulsed high-voltage discharge plasma resulted in 72% COD and 74% phenol degradations with the addition of H 2 O 2 , and 74% COD and 79% phenol degradation with the addition of ferrous ions.…”

“…Although there are some studies on OMWW plasma treatments [8,9], as well as the removal of phenol and phenolic compounds and organics by the plasma method [14][15][16][17], far too little attention has been paid to the effects of high voltage electrical discharge plasma (HVED) treatments on OMWW compounds, which is the goal of our paper.…”