Schmutzdecke, the biofilm formed on the top of the sand bed in household slow sand
filters (HSSF) is a key factor for the filters’ high efficiency in removing particles and microorganisms
from water. This paper aims to investigate the extracellular polymeric substances composition
(carbohydrates and proteins), biomass, dissolved oxygen, and microbial community in two types
of HSSFs and identify a correlation between them and their efficiency. A continuous- and an
intermittent-HSSF (C-HSSF and I-HSSF) were studied to treat river water for 48 days. Their efficiencies
for bacteria (E. coli and total coliforms), turbidity, and apparent color removals were analyzed.
Results clearly showed an increase of carbohydrates (from 21.4/22.5 to 101.2/93.9 mg·g
for C-/IHSSF) and proteins (from 34.9 to 217/307.8 mg g-1 for C-/I-HSSF), total solids (from 0.03/<0.03
to 0.11/0.19 g L−1
for C-/I-HSSF), dissolved oxygen depletion inside the filter (6.00 and 5.15 mg
for C- and I-HSSF) and diversity of microorganisms over time, pointing out the schmutzdecke
development. A clear improvement on the HSSFs’ efficiency was observed during operation, i.e.,
E. coli removal of 3.23 log and 2.98 log for total coliforms, turbidity from 60 to 95%, and apparent
color from 50 to 90%.
|Number of pages||17|
|Publication status||Published - 29 Mar 2022|
We acknowledge the Global Challenges Research Fund (GCRF) UK Research and Innovation for funding SAFEWATER; EPSRC Grant Reference EP/P032427/1 and the Royal Society for funding the project reference ICA/R1/201373 under the International Collaboration Awards 2020. The authors would also like to thank Coordination for the Improvement of Higher Education Personnel (CAPES-PROEX—Brazil, Financial code 001) for the MSc and PhD scholarships awarded and to Amanco-Mexichem (São Paulo, Brazil) for donating the materials to make the filters.
- drinking water
- extracellular polymeric substances (EPS)