Characterization of Clogging Material From Horizontal Subsurface Flow Constructed Wetland Systems

Abstract

This study aimed to characterize the material composition responsible for clogging the porous medium of horizontal subsurface flow constructed wetland (HSSF-CW) systems, which is detrimental to a proper system operation. Six completely clogged HSSF-CWs were used after treatment of swine wastewater. Operating conditions of these systems were named CW-C (HSSF-CW 1 and HSSF-CW 4, non-cultivated, i.e. controls), CW-T (HSSF-CW 2 and HSSF-CW 5, cultivated with Tifton 85 (Cynodon spp.)), and CW-A (HSSF-CW 3 and HSSF-CW 6, cultivated with alligator weed (Alternanthera philoxeroides)). The results showed that most of the clogging material was composed of total fixed solids (95, 84, and 82% in CW-C, CW-T, and CW-A, respectively). However, total volatile solids (TVS) mostly affected pore clogging. The larger accumulations and productions of TVS in CWs might have originated from dead plants.

Clogging index: A tool to quantify filter bed clogging in horizontal subsurface flow macrophyte‐assisted vermifilter

“…Plant growth's role in clogging filter beds is a debatable topic. Few studies observed that the accumulation and translocation of plant detritus that was generated through growth with the frequent falls of leaves, death of the matured roots, and other parts might cause premature clogging of a filter bed (Knowles et al, 2011; Miranda et al, 2017). Similarly, the growth of an abundant amount of fine roots occupies the pre‐existing pores, leading to temporal clogging (Bodner et al, 2014; Tang et al, 2017), whereas other reports claimed that plants could be beneficial to the constructed wetlands by counteracting the effects of clogging by making the substrate more porous due to the bulking or swelling of the filter bed medium that results from plant root growth (Carvalho et al, 2013; Lombard Latune et al, 2017).…”

Monitoring of horizontal subsurface flow constructed wetlands for tertiary treatment of municipal wastewater

“…With the operation of the system, the void space is potentially prone to clogging by the gradual accumulation of substrate comprising suspended solids, biological films, chemical precipitates, plant residues, etc. (Miranda et al 2017 ; De Matos et al 2018 ). In general, the gradual net accumulation of this mixture in pore spaces yield surface overland flow with a clogging of CW (Liu et al 2018a ; Vymazal 2018 ; Vasconcellos et al 2019 ).…”