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Cork boiling wastewaters (CBW) are strongly coloured complex aqueous solutions with high organic load of biorecalcitrant and toxic nature. The feasibility and efficiency of a CBW treatment process combining ozonation as pre- and post-treatment of a horizontal subsurface flow constructed wetland (HSFCW) was assessed. Over an extended monitoring period of 390 days, two lab-scale HSFCW units were tested; one planted with P. australis (CWP) and one unplanted-control (CWC) operated at average organic loads rates (OLR) of 5 and 10 g COD/m 2 /d. CWP always outperformed the control unit. The ozonation trials were run at pH values of 8.15-8.21 and 5.39-5.45 (without adjustment) at ozone to COD ratios of 0.25-0.29 and 0.24-0.59 when implemented as pre- and post-treatment, respectively. Average removals (calculated through mass balance basis) were 78-88%, 86-91%, 71-89% and 43-89% for COD, BOD 5 , Total Phenols (TPh) and colour when ozonation was implemented as post-treatment. For ozonation as pre-treatment, respective figures were 77-80%, 79-92%, 78-85% and 19-73%. Regardless of the treatment scheme and OLR, ozonation was very effective in biodegradability increase (i.e., BOD 5 /COD) from 0.18 to 0.42 when applied as pre-treatment, and decolourization after the HSFCW increased from 21% to 91% (post-treatment) with respective ozone consumed yields of 67-69% and 72-85%. The best results were obtained for the scheme CWP + Ozonation at OLR of 5.33 g COD/m 2 /d with COD reductions from 1950 mg/L to 81-88 mg/L in the effluent and TPh from 125 mg/L to 5-6 mg/L at limited ozone amounts of 0.21-0.45 g O 3 /m 2 /d., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Industrial wastewaters represent a serious threat to the environment due to their variable and complex composition. Though mostly mechanical systems are used for treatment of such wastewater, there is growing need for sustainable and cost-effective solutions, especially in low-income regions. In this study, a horizontal sub-surface flow Constructed Wetland (HSFCW) system was used for the first time to treat wastewater from a glass manufacturing industry in Iran. In order to de-risk the treatment approach, a pilot system consisting of a settling tank and a HSFCW was first tested for 4 months. The results of the pilot study were then used to build the full-scale CW system treating 10 m³/day. In general, the tested design proved to be very effective reaching high removal rates of BOD 5 , COD, and TSS (90, 90, and 99, respectively), as also for TN and TP (>90%). The high efficiency of the tested system allowed for the recycle and reuse of the treated effluent in the glass manufacturing processes, reducing this way the fresh water consumption in the glass industry and the related operational costs., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Tannery wastewater is characterized by high and variable concentrations of diverse pollutants, which makes it difficult and costly to treat. In the search for sustainable treatment options for tannery effluents, two pilot-scale horizontal subsurface flow (HSF) constructed wetlands (CW) were built and operated for the treatment of synthetic water of quality similar to that of pre-treated tannery effluents. Five different loading phases were examined with gradual increase of inflow COD, NH4+-N and Cr loads until reaching and exceeding the typical composition of a tannery effluent. High COD and NH4+-N removals were observed (82 and 96%, respectively), and almost complete Cr removal in the outflow, which met the Venezuela national standards for environmental discharge. Plant uptake was measured, but microbial processes appear to be the main ammonium transformation/removal mechanism. Nitrogen, chlorophyll and Cr in the plant aerial parts and roots indicated the capacity of Phragmites sp. to grow and survive even under high loads. The measured heterotrophic bacteria in the substrate and rhizomes indicated the biofilm development and the oxidation of organic matter and nitrogen. Water losses via evapotraspiration were also measured and reached 14%. Overall, the tested CW design proved to be a sustainable and feasible alternative for the treatment of tannery wastewater in tropical climates., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

The feasibility and treatment efficiency of horizontal subsurface flow constructed wetlands (HSFCW) was assessed for the first time for cork boiling wastewater (CBW) through laboratory experiments. CBW is known for its high content of phenolic compounds, complex composition of biorecalcitrant and toxic nature. Two lab-scale units, one planted with Phragmites australis (CWP) and one unplanted (CWC), were used to evaluate the removals of COD, BOD, total phenolic compounds (TPh) and decolourization over a 2.5-years monitoring period under Mediterranean climatic conditions. Seven organic and hydraulic loading rates ranging from 2.6 to 11.5 g COD/m 2 /d and 5.7-9.1 L/m 2 /d were tested under average hydraulic retention time (HRT) of 5 ± 1 days required due to the CWB limited biodegradability (i.e., BOD 5 /COD of 0.19). Average removals of the CWP exceeded those of the CWC and reached 74.6%, 91.7% and 69.1% for COD, BOD 5 and TPh, respectively, with respective mass removals rates up to 7.0, 1.7 and 0.5 (in g/m 2 /d). Decolourization was limited to 35%, since it mainly depends on physical processes rather than biodegradation. CBW concentration of nine phenolic compounds ranged from 1.2 to 38.4 mg/L (for the syringic and ellagic acids, respectively) in the raw CBW, with respective removals in the CWP unit ranging from 41.8 to 76.3%, higher than those in the control unit. Despite CBW high concentration of TPhs (average of 116.3 mg/L), the HSFCW reached organic load removals higher than those of conventional biological treatment methods., (Copyright © 2018 Elsevier Ltd. All rights reserved.)