How does the pre-treatment of landfill leachate impact the performance of O-3 and O-3/UVC processes?

• Type: Article in International Scientific Journal
• Date: 2021

Authors

Ana I. Gomes (Author) FEUP; Bianca M. Souza-Chaves (Author) Other; Minkyu Park (Author) Other; Tânia F. C. V. Silva (Author) Other; Rui Boaventura (Author) FEUP; Vítor J. P. Vilar (Author) FEUP

Journal

Title: Chemosphere

Vol. 278

Pages: 1-13

ISSN: 0045-6535

Publisher: Elsevier

Indexing

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Other information

Authenticus ID: P-00T-SGW

DOI: 10.1016/j.chemosphere.2021.130389

Abstract (EN): In this study, O-3 and O-3/UVC processes were evaluated for the treatment of landfill leachate after biological nitrification/denitrification, coagulation, or their combinations. The O-3-driven stage efficiency was assessed by the removal of color, organic matter (dissolved organic carbon (DOC) and chemical oxygen demand (COD)), and biodegradability increase (Zahn-Wellens test). Also, fluorescence excitation-mission matrix (EEM) and size exclusion chromatography coupled with OC detector (SEC-OCD) analysis were carried out for each strategy. The bio-nitrified-leachate (L-N) was not efficiently mineralized during the O-3-driven processes since the high nitrites content consumed ozone rapidly. In turn, carbonate/bicarbonate ions impaired the oxidation of the bio-denitrified-leachate (L-D), scavenging hydroxyl radicals (HO center dot) and inhibiting the O-3 decomposition. For both bio-leachates, only O-3/UVC significantly enhanced the effluent biodegradability (>70%), but COD legal compliance was not reached. EEM and SEC-OCD results revealed differences in the organic matter composition between the nitrified-coagulated-leachate (L-NC) and denitrified-coagulated-leachate (L-DC). Nonetheless, the amount of DOC and COD removed per gram of ozone was similar for both. Cost estimation indicates the O-3-driven stage as the costliest among the treatment processes, while coagulation substantially reduced the cost of the following ozonation. Thus, the best treatment train strategy comprised L-DC (with methanol addition for denitrification and coagulated with 300 mg Al3+/L, without pH adjustment), followed by O-3/UVC (transferred ozone dose of 2.1 g O-3/L and 12.2 kJ(UVC)/L) and final biological oxidation, allowed legal compliance for direct discharge (for organic and nitrogen parameters) with an estimated cost of 8.9 (sic)/m(3) (O-3/UVC stage counting for 6.9 (sic)/m(3)).

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 13