Slow sand filtration for biofouling reduction in seawater desalination by reverse osmosis

Autor(es)

de Oliveira, Fernando Freitas ^{[1, 2]} ; Schneider, Rene Peter ^[3]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Inst Ciencias Biomed, Programa Posgrad Interunidades Biotecnol, Ave Prof Lineu Prestes, 1374, Cidade Univ, BR-05508900 Sao Paulo, SP - Brazil

^[2] Univ Sao Paulo, CEBIMAR Ctr Biol Marinha, Rodovia Manoel Hypolito Rego, Km 131, BR-11600000 Sao Sebastiao, SP - Brazil

^[3] Univ Sao Paulo, Polytech Sch, Dept Chem Engn, Ave Prof Luciano Gualberto, Travessa 3, 380, BR-05508900 Sao Paulo, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: WATER RESEARCH; v. 155, p. 474-486, MAY 15 2019.
• Citações Web of Science: 0

Resumo

Control of the organic substrate pool that determines the microbial growth potential (MGP) of feedwater in seawater reverse osmosis (SWRO) is a challenge unresolved in conventional or advanced membrane pretreatment. Slow sand filtration (SSF) combines filtration with biodegradation, but its capability of reducing MGP, proteins and carbohydrates on seawater feeds is not known. Two SSF, one constructed with new media (newSSF) and one from a previous filtration run (oldSSF), reduced MGP as measured in a growth assay with the marine organism Pseudoalteromonas songiae by one order of magnitude after maturation periods of 76 and 61 days, respectively. The reduction of the amount of biopolymers deposited on the surfaces of SWRO membranes in laminar fluid flow cells was significant with filtrates from biologically non-acclimated SSF (proteins: -60% (oldSSF) and -66% (new SSF), carbohydrates: 75% (oldSSF) and -70% (newSSF)) and an even greater reduction was observed after filter maturation (proteins: 81% (oldSSF) and -76% (new SSF), carbohydrates: 88% (oldSSF) and -88% (newSSF). Turbidity was less than 0.3 nephelometric turbidity units (NTU) and silt density index (SDI) <4 immediately after startup and during the 181 days operating period regardless of the oscillations of the raw sea water quality. Filtration and biological activity were restricted to the top 30 cm of the media column, with no significant further contribution of the deeper media layers to filtrate quality. (C) 2019 Elsevier Ltd. All rights reserved. (AU)

• Processo FAPESP: 13/50435-3 - Sistemas de separação por membranas para o abastecimento público: mecanismos de contratação de projetos e tratamento de águas subterrâneas contaminadas
• Beneficiário: René Peter Schneider
• Modalidade de apoio: Auxílio à Pesquisa - Parceria para Inovação Tecnológica - PITE