A pilot study of three-stage biological–chemical treatment of landfill leachate applying continuous ferric sludge reuse in Fenton-like process

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• 作者：Kati Klein ; Arthur Kivi ; Niina Dulova…
• 关键词：Combined treatment ; Landfill leachate ; Fenton ; like process ; Biological treatment ; Ferric sludge reuse ; Water exchange ratio
• 刊名：Clean Technologies and Environmental Policy
• 出版年：2017
• 出版时间：March 2017
• 年：2017
• 卷：19
• 期：2
• 页码：541-551
• 全文大小：
• 刊物类别：Engineering
• 刊物主题：Sustainable Development; Industrial Chemistry/Chemical Engineering; Industrial and Production Engineering; Environmental Engineering/Biotechnology; Environmental Economics;
• 出版者：Springer Berlin Heidelberg
• ISSN：1618-9558
• 卷排序：19

文摘

This pilot study describes a three-stage continuous process for treating landfill leachate containing significant concentrations of recalcitrant organic substances. The proposed technological scheme consisted of an activated sludge pre-treatment combined with a Fenton-like process enhanced by continuous sludge reuse and followed by an activated sludge post-oxidation. Biological pre-treatment removed >99, 86, >99, 83 and 86 % of BOD₇, COD, NH₄+–N, phenols and the sum of lignin and tannins, respectively. Operational conditions in the ferric sludge-catalysed Fenton-like process stage were carefully adjusted in order to maintain the efficacy and practicability of combined treatment scheme. Although the application of ferric sludge as a catalyst in the Fenton-like oxidation reduced COD removal efficiency by 32 % as compared to the conventional Fenton process, lower process efficiency was compensated by reducing the water exchange ratio to 50 % without increasing the consumption of reagents. Moreover, an intermittent addition (added to every second treatment cycle) of fresh ferrous iron catalyst at a H₂O₂/Fe2+ w/w ratio of 20/1 increased the BOD₇/COD ratio from 0.04 to 0.32 and resulted in 60 % COD removal. A cyclic addition (added to every treatment cycle) of the same amount of catalyst increased the BOD₇/COD ratio from 0.09 to 0.32, and a 10 % higher COD removal efficiency as compared to intermittent catalyst addition was achieved. Finally, biological post-treatment of the leachate resulted in more than 95 % removal of each measured parameter. Overall, the combined technological scheme with continuous ferric sludge reuse in the Fenton-like stage proved promising alternative for landfill leachate treatment.