Phytotoxicity of grey wastewater evaluated by toxicity tests

Abstract

An algal growth inhibition test and a short-term acute assay for willows were used in order to evaluate the phytotoxicity of grey wastewater from different sources. Bathroom grey wastewaters were toxic towards algae (EC₁₀ = 36 – 375 mL/L), whereas kitchen and laundry wastewaters were found to be toxic to both organisms (EC₁₀ = 55 – 198 mL/L). The investigation showed that untreated grey wastewater could pose an environmental hazard if discharged into small-size receiving waters. Discharge to willow evaporation beds is problematic and toxic effects may be encountered, but, compared to direct discharge to surface water, the risks of toxic effects are much less pronounced.

Keywords:

• Detergents
• Greywater
• Pseudokirchneriella subcapitata
• Willow tree
• Xenobiotic organic compounds

Acknowledgements

The authors acknowledge the following E&R DTU staff: Associate Professor Stefan Trapp, PhD student Giovanella Ciucani and laboratory technician Susanne Kruse. Morten Andersson, Moe & Br⊘dsgaard Consulting Engineers are thanked for providing access to Nordhavnsgården.