Abstract:
The study is an experimental investigation into the use of water
hyacinth for removal of pollutants in sewage. This system is
considered as low cost technology, alternate to conventional
treatment system for sewage treatment in hot climates. Cost
estimates for sewage treatment in ponds system using water
hyacinth and. without water hyacinth is compared. Ponds with
water hyacinth has been found cheaper than conventional
treatment system.
From the literature review it was apparent that little work had
been carried out on pollutant removal process from sewage using
water hyacinth. The shallower depths and the presence of water
hyacinths in place of algae are the major differences between
treatment systems with water hyacinths and stabilization ponds.
The' water hyacinths, themselves, bring about little actual
treatment of the waste water. Their function is to provide
components of the aquatic environment that improve the waste
water treatment capability and/or reliability of that
environment.
Survival and growth rate of water hyacinth were observed, when
this plant was grown on sewage. Longer type water hyacinth is
seen continue to survive in sewage having maximum initial BODs of"
110 mg/l.
Evapotranspira-t:ion and Evaporation rate from sewage with and
without water hyacinths were determined in various conditions.
Three types of water hyacinths were used to determine
evapotranspiration rate from different concentration of sewage
sample. Evaporation rate from sewage sample were determined in
similar condition to evapotranspiration test. Evapotranspiration
rate is seen 2 to 4.5 times higher than evaporation rate in the
similar condition. Characterization of pollutant removal from sewage with water
hyacinth were done in various conditions primary importance was
given to findout the removal performance of organic loadings,
suspended solids (ss) and Nutrient Concentration (P&N).
Higher pollutants removal rate have been found in case of sewage
treatment with water hyacinth than without water hyacinth. In
general removal of organic matter in water hyacinth system is 8-
15% and removal of other pollutants are 10-25% greater than
without water hyacinth system.
