Development of toxicity tolerant water hyacinth (Eichhornea crassipes) for effective treatment of raw sewage

Abstract

Pioneering research efforts in the handling of municipal sewage in developing countries have involved the use of water hyacinth (Eichhomea crassipes) to purify sewage for possible re-use of the effluent water for domestic purposes. The ability of water hyacinth to remove pollution from raw sewage has been found to be impaired by sewage toxicity. Trials were therefore carried out to adapt water hyacinth to toxicity and thereby increase its .ability to remove pollutants from raw sewage. The plants were adapted using an active bio-degrader consisting of Pseudomoms aeruginosa, Escherichia coli, Klebsiella ozaenae, Klebsiella edwardriella and Baccillus subtilis. The adaptation progressed through 20,40.60 and 80% sewage dilution until plants capable of growth in 100% raw sewage were obtained. Plants were observed for morphological growth and at four weeks, samples were collected for tissue analysis. The plants progressively absorbed nutrients from sewage up to the fourth week, when signs of toxicity were observed through wilting. loss of turgidity and reduction in leaf number. However, plants that survived through a series of adaptations under various sewage dilutions exhibited luxuriant growth on raw sewage. In synergy with the active bio-degrader. the efficiency of the adapted water hyacinth to remove pollutants (nutrients) from raw sewage was enhanced by 93%.

The Multifaceted Function of Water Hyacinth in Maintaining Environmental Sustainability and the Underlying Mechanisms: A Mini Review

“…Additionally, inoculation with Bacillus subtilis , B. mucilaginosus , or Aspergillus niger in WH roots promoted its biomass by increasing the maximum photochemical efficiency [ 122 ]. Moreover, the exogenous addition of Pseudomnas aeruginosa , Escherichia coli , Klebsiella ozanae , K. edwardriella and B. subtilis ensured the growth of WH in toxic raw sewage, while non-inoculated plants could barely survive [ 123 ]. These studies uncovered the growth-promoting effect on WH of micro-organisms and partially explained the growth of WH in toxic polluted water.…”