Treatment of wash basin and bathroom greywater with Chlorella variabilis and reusability

Oktor K. , Çelik D.

Journal of Water Process Engineering, vol.31, 2019 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 31
  • Publication Date: 2019
  • Doi Number: 10.1016/j.jwpe.2019.100857
  • Title of Journal : Journal of Water Process Engineering


Domestic wastewater excluding toilet streams is called greywater. When it is collected only from wash basin and

bathroom, it is named as “light greywater” because of embodying a small fraction of contaminants. Light

greywater makes up of more than 50% of the domestic wastewater with a great reusability potential when

properly treated. Henceforth, greywater treatment can be a part of preservation of fresh water resources.

Nowadays, advanced treatment methods requiring high investment and operating costs are used for greywater

treatment. However, bioremediation of greywater can be an economic alternative as a result of low energy

requirement of microalgal remediation systems. Moreover, microalgae can be harvested to refine its oil for

further processes. In this study, treatment of light greywater with Chlorella variabilis is investigated. Wash basin

and bathroom light greywater samples were collected and treated separately. After the initial chemical and

microbiological analyses, the suspended solids were removed via centrifugation. Then, microalgae cultivated in

raw greywater and 30% diluted (with tap water) samples. After 19 days of cultivation, Chlorella variabilis was

removed from the media by another centrifuge. Final analyses were done, and removal efficiencies of COD,

BOD5, TP and TN were calculated in addition to total coliform, Escherichia coli, Enterococcus, total bacteria, and

Pseudomonas aeruginosa analyses. The results show up to 92.3% COD, 91.9% BOD5, 85.6% TN and>97% TP

remediation. Additionally, microbiological analysis results show this water can be reused for toilet flushing.