Biological Layer in Household Slow Sand Filters: Characterization and Evaluation of the Impact on Systems Efficiency
Helen Lubarsky,
Natália de Melo Nasser Fava,
Bárbara Luíza Souza Freitas,
Ulisses Costa Terin,
Milina Oliveira,
Atônio Wagner Lamon,
Natalia Pichel,
John Anthony Byrne,
Lyda Patricia Sabogal-Paz,
Pilar Fernandez-Ibañez
Affiliations
Helen Lubarsky
Nanotechnology and Integrated Bioengineering Centre, School of Engineering, Ulster University, Coleraine BT37 0QB, UK
Natália de Melo Nasser Fava
Department of Hydraulics and Sanitation, São Carlos School of Engineering, University of São Paulo, Avenida Trabalhador São-Carlense 400, São Carlos 3566-590, Brazil
Bárbara Luíza Souza Freitas
Department of Hydraulics and Sanitation, São Carlos School of Engineering, University of São Paulo, Avenida Trabalhador São-Carlense 400, São Carlos 3566-590, Brazil
Ulisses Costa Terin
Department of Hydraulics and Sanitation, São Carlos School of Engineering, University of São Paulo, Avenida Trabalhador São-Carlense 400, São Carlos 3566-590, Brazil
Milina Oliveira
Department of Hydraulics and Sanitation, São Carlos School of Engineering, University of São Paulo, Avenida Trabalhador São-Carlense 400, São Carlos 3566-590, Brazil
Atônio Wagner Lamon
Department of Hydraulics and Sanitation, São Carlos School of Engineering, University of São Paulo, Avenida Trabalhador São-Carlense 400, São Carlos 3566-590, Brazil
Natalia Pichel
Nanotechnology and Integrated Bioengineering Centre, School of Engineering, Ulster University, Coleraine BT37 0QB, UK
John Anthony Byrne
Nanotechnology and Integrated Bioengineering Centre, School of Engineering, Ulster University, Coleraine BT37 0QB, UK
Lyda Patricia Sabogal-Paz
Department of Hydraulics and Sanitation, São Carlos School of Engineering, University of São Paulo, Avenida Trabalhador São-Carlense 400, São Carlos 3566-590, Brazil
Pilar Fernandez-Ibañez
Nanotechnology and Integrated Bioengineering Centre, School of Engineering, Ulster University, Coleraine BT37 0QB, UK
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−1 for C-/I-HSSF) and proteins (from 34.9 to 217/307.8 mg g−1 for C-/I-HSSF), total solids (from 0.03/−1 for C-/I-HSSF), dissolved oxygen depletion inside the filter (6.00 and 5.15 mg L−1 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%.
