Treatment of Domestic Wastewater Using Duckweed (Lemna gibba)

Abstract

In Palestine, the generation of wastewater becomes a serious problem that needs to be solved in a sanitary way. Most of the generated wastewater in Palestine is either dumped in unsealed cesspits as first choice or – in “good” cases – collected then dumped in open wades. Both ways lead to many environmental problems, e.g. bad odors emissions, insects’ proliferation, pollution of both surface and groundwater bodies, diseases spreading, and soil contamination. Despite the fact that wastewater itself should be considered a source of fresh water, especially in a semi-arid country under occupation like Palestine, a one well-known method to minimize the pollutants in wastewater is to apply Duckweed treatment system. In this project indoor and outdoor containers were used, each was filled to a certain height with domestic wastewater (not sewage) from Beit Alsharq restaurant and covered with the DW species (Lemna gibba). This experiment was conducted to evaluate the performance of Duckweed (Lemna gibba) as a tool to reduce the amount of pollutants in the domestic wastewater by using low cost and simple technology and to use the harvested DW as a fodder for chicks, in order to apply minimum waste technology to reach sustainable development. The removal efficiency of indoor Duckweed container for BOD, COD and NH 4 + -N was found to be about 41.1%, 75.3%, 65.3% respectively. While the removal efficiency of outdoor Duckweed container for BOD, COD and NH 4 + -N was found to be about 80.7%, 92.4%, 98.6% respectively. It was found that the chicks fed with the mixture of dried DW and ordinary fodder (ratio 1:1) have grown faster than those fed with only ordinary fodder. Based on these simple preliminary results, it was concluded that the use of DW to treat wastewater was very effective, and breeding the chicks under ideal conditions and fed them with the mixture of harvested DW and fodder could lead to better chicks growth, and all of which achieve sustainable development.