New articles on biofilters build on early CRCWSC research

March 20, 2023
Two recent articles published in the International Water Association’s Blue-Green Systems journal build on early research by the CRC for Water Sensitive Cities on biofilters and stormwater management.

Copper(II) hydroxide/oxide-coated granular activated carbon for E. coli removal in water explores the effectiveness of using filter media (granular activated carbon) coated with copper hydroxide in removing bacteria from water. Granular activated carbon (GAC) has long been used to filter water to remove physical, chemical and microbial contaminants to produce safe drinking water. Research has showed adding a metal coating to this media improves microbial removal. Other studies have explored using silver, aluminium and iron coatings. This latest study explores using copper, and found large-scale application is economically feasible:

  • Not only did the modified media remove bacteria at a fast flow rate, it inhibited the survival of retained bacteria during prolonged contact.
  • Copper is low cost and can be easily coated onto GAC.
  • Copper leaching can be controlled by adjusting the salinity of the water.

Zero additional maintenance stormwater biofilters: from laboratory testing to field implementation explores using zero additional maintenance (ZAM) biofilters in stormwater biofilters. Stormwater biofilters (e.g. raingardens and bioretention systems) are a widely-used nature-based solution to managing urban water. However, they require high levels of maintenance to remain effective. This study explored the design and operation of ZAM biofilters. It found:

  • a filter media layer protected against surface clogging, particularly smaller particles
  • 5 lawn grasses reduced nitrogen concentrations and met other local pollution reduction requirements
  • field ZAM biofilters did not clog and had high pollutant removal, complying with guidelines
  • ZAM biofilters successfully managed stormwater, with only streetscape landscaping.

These studies build on early research by the CRC for Water Sensitive Cities on biofilters and stormwater management. Project C4.1 (Integrated multi-functional urban water systems) developed multi-functional hybrid water sensitive urban design systems capable of treating multiple water sources within urban landscapes. In particular, it focused on developing and optimising stormwater biofiltration and wetland systems that can better protect our waterways and cool our cities. It also explored ways to improve the aesthetic appeal of biofilters.