A pilot-scale evaluation of residual sludge quality in a worm-sludge treatment reed bed in the Mediterranean region

Gholipour, Amir; Fragoso, Rita; Galvão, Ana; Duarte, Elizabeth

http://hdl.handle.net/10400.5/102867

Use this identifier to reference this record.

Name:	Description:	Size:	Format:
1-s2.0-S0301479724027580-main.pdf		6.22 MB	Adobe PDF	Download

Send Feedback

Authors

Abstract(s)

A pilot-scale study on sludge treatment reed beds investigated the combined effects of earthworms and Arundo donax on sewage sludge dewatering and residual sludge quality. Four units were tested: one planted with earthworms, one planted without earthworms, one unplanted with earthworms, and one control, each unit replicated. Over a year, 24 cycles of sludge (dry and volatile solid contents of 24.71 g.L 1, and 19.14 g.L 1) were fed onto the units at a sludge loading rate: 43.59 kg.DS.m 2.year 1. Afterward, the units experienced 132 days of resting period, increasing dry solids from 21 to 70 % and decreasing volatile solids from 81 to 69 % on average (40 % sludge volume reduction). The bottom layers of the planted unit with earthworms showed a 30 % reduction in volatile solids, indicating improved sludge stabilization. Macronutrient abundance in the residual sludge followed the sequence N > Ca > P > K > S > Mg. The planted unit with earthworms reduced micro- nutrient concentrations by 22 % compared to the control unit (Fe > Na > Mn > B > Mo). Earthworms also played a key role in reducing heavy metal concentrations by 11 % compared to the planted unit without earthworms (Zn > Cr > Pb > Ni > Cd). Heavy metal levels in the residual sludge met EU and Portugal standards, with a 99.9 % reduction in Escherichia coli and fecal coliforms. Cost estimation showed centrifugation and W-STRB scenarios cost 167 and 183 €.PE 1 for a ten-year operation, with O&M costs of 7 and 3 €.PE 1.year 1, respectively

Keywords

Eisenia fetida Sewage sludge Constructed wetland Arundo donax Cost assessment

URI

http://hdl.handle.net/10400.5/102867

Citation

Gholipour, Amir, et al. «A Pilot-Scale Evaluation of Residual Sludge Quality in a Worm-Sludge Treatment Reed Bed in the Mediterranean Region». Journal of Environmental Management, vol. 370, novembro de 2024, p. 122772. https://doi.org/10.1016/j.jenvman.2024.122772.