Surface-modified biochar in a bioretention system for Escherichia coli removal from stormwater

Abbe Y.T. Lau, Daniel C.W. Tsang, Nigel J.D. Graham, Yong Sik Ok, Xin Yang, Xiang dong Li

Research output: Contribution to journalArticle

28 Citations (Scopus)

Abstract

Bioretention systems have been recommended as one of the best management practices for low impact development for water recycling/reuse systems. Although improvement of the stormwater quality has been reported regarding pollutants eliminations such as suspended solids and heavy metals, a substantial removal of indicator bacteria is required for possible non-potable reuse. This study investigated the efficiency of wood biochar with H2SO4-, H3PO4-, KOH-, and amino-modifications for E. coli removal from synthetic stormwater under intermittent flow. The H2SO4-modified biochar showed a specific surface area of 234.7 m2g−1(approximately double the area of original biochar), whereas a substantial reduction in surface area was found with amino-modified biochar. The E. coli removal (initial concentration of 0.3–3.2 � 106CFU mL−1) by modified biochars as filter media was very promising with, for example, over 98% removal efficiency in the first 20 pore volumes of stormwater infiltration and over 92% removal by the end of the second infiltration cycle. Only a small portion of E. coli attached on the modified biochars (<0.3%, except KOH- and amino-modified biochars) was remobilized during the drainage phase of intermittent flow. The high removal capacity and stability against drainage were attributed to the high surface area, porous structure, and surface characteristics (e.g. hydrophobicity and O-containing functional groups) of the biochars. Thus, the H2SO4-modified biochar appeared to give the best treatment performance.

Original languageEnglish
Pages (from-to)89-98
Number of pages10
JournalChemosphere
Volume169
DOIs
Publication statusPublished - 2017 Jan 1
Externally publishedYes

Fingerprint

stormwater
Escherichia coli
surface area
infiltration
drainage
Infiltration
Drainage
best management practice
hydrophobicity
Water recycling
functional group
removal
biochar
recycling
heavy metal
Hydrophobicity
Heavy Metals
filter
Specific surface area
Functional groups

Keywords

  • Bacteria removal
  • Bioretention systems
  • Designer biochar
  • Intermittent flow
  • Stormwater harvesting

ASJC Scopus subject areas

  • Environmental Chemistry
  • Chemistry(all)

Cite this

Surface-modified biochar in a bioretention system for Escherichia coli removal from stormwater. / Lau, Abbe Y.T.; Tsang, Daniel C.W.; Graham, Nigel J.D.; Ok, Yong Sik; Yang, Xin; Li, Xiang dong.

In: Chemosphere, Vol. 169, 01.01.2017, p. 89-98.

Research output: Contribution to journalArticle

Lau, Abbe Y.T. ; Tsang, Daniel C.W. ; Graham, Nigel J.D. ; Ok, Yong Sik ; Yang, Xin ; Li, Xiang dong. / Surface-modified biochar in a bioretention system for Escherichia coli removal from stormwater. In: Chemosphere. 2017 ; Vol. 169. pp. 89-98.
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