Biomass Production of Azolla pinnata in Different Wastewater

Abstract

Usage of Azolla pinnata in wastewater treatment has great advantages in the environment. Besides
its utilization as a water purifier plant on wastewater, Azolla sp. can be used as an animal feed and
bio fertilizer. This research study was conducted to assess the biomass production and the treatment
efficiency of Azolla sp. in different types of industrial wastewater from rice mills, the food industry
and vehicle services stations. A split-plot experimental design was used with 4 replicates. For this
study, eight artificial ponds were constructed by using polythene sheets. The size of each pond were
150×50×40 cm3
. Out of eight ponds, three ponds were filled with three different types of wastewater,
one was filled with groundwater and 90 g of Azolla sp. plants were introduced into them. Further,
balance four ponds were filled with the same three different types of wastewater and groundwater.
Ground water was used as a control to observe the growth of Azolla sp. without effect of wastewater.
Each of the ponds was filled with 50 L of wastewater. Then the water quality parameters such as pH,
EC, COD, BOD, TDS, TSS, temperature, oil and grease content and the biomass production of Azolla
sp. were analyzed on the first day, the 7th day and the 14th day. Most of the water quality parameters
in three different types of industrial wastewater were improved with Azolla sp. Significantly, a higher
dry weight of Azolla pinnata was recorded in rice mill wastewater and the least values recorded in
the service station wastewater. There are significant differences (p<0.05) among the water quality
parameters such as EC, TDS and TSS of the four experiments. A significant difference was observed
in EC, TDS and TSS of the Azolla sp. grown rice mill wastewater compared to control. EC of the
food industry wastewater showed a higher significant difference. EC and temperature showed a
highly significant difference in the service station wastewater.

Keywords: Azolla pinnata, Waste water, Biomass, Water quality