Dewatering and Mineralization of Sludge in Vertical Flow Constructed Wetlands: A Review

Abstract

Sludge treatment in vertical flow constructed wetlands (VFCWs) is a promising alternative to conventional treatment, which provides adequate treatment at low-cost, while being energy efficient. They may dewater and mineralize various kinds of sludge, including surplus sludge from activated sludge systems, agricultural slurries, and septage and faecal sludge effectively. This paper presents a review of the state-of-the-art of VFCWs treating sludge. The effects of varying design and operational parameters, as well as environmental factors on treatment performance are discussed. The paper also summarizes the performance of various pilot- and full-scale systems in terms of final dry matter content and degree of mineralization. In order to understand the governing processes and predict its performance, modelling of VFCWs in sludge treatment is suggested.