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Unconventional Wastewater Treatment Systems

Understanding Wastewater Treatment

Studies sponsored by P&G at the University of Manchester in conjunction with Yorkshire Water have demonstrated the efficacy of constructed wetlands (reed beds) in removing key detergent components such as anionic surfactants, boron and phosphate. For example, removal rates for anionic surfactants in reed beds used for secondary treatment by Yorkshire Water have been measured at 97-99%.

These levels are comparable to other conventional secondary treatment technologies such as Trickling Filters, Activated Sludge or Rotating Biological Contactors (RBCs). Yorkshire Water is one of the few U.K. water companies to make use of reed beds for small communities, and some of their installations have been in commission since the first decade of the 20th century. As such, they have been and continue to be exposed to sewage containing detergent components, without apparent adverse effects.

Other studies conducted with a demonstration-scale facility at Manchester University employed artificially elevated concentrations of detergent components in a deliberate attempt to disturb the biology of the system in order to establish the threshold of potential adverse effects. This threshold proved to be at concentrations significantly higher than those that will be encountered in normal sewage effluent.

Together, these studies:

  • Confirm the efficacy of reed beds in the treatment of detergent laden sewage
  • Establish that concentrations of detergent components in normal sewage are not detrimental to the effective functioning of the reed beds themselves

The academic supervisor at the University of Manchester was Dr. Keith White (, and he can confirm details of these studies. Students who worked on reed beds included:

  • Elena Kostadinova (1995). MSc Thesis, Manchester University, U.K.
  • Paul Fairclough (2000). MSc Thesis, Manchester University, U.K.
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