Using Analytical Hierarchical Process for Selection of Macrophytes in Constructed Wetlands for Dairy Wastewater Treatment

Abstract

Constructed wetlands are nature based cost effective solution for wastewater treatment. Selection of macrophytes is tricky and a much needed skill to gain maximum output from constructed wetlands. Selection of macrophyte can have multiple criteria involved with different significance. However, no article could be found which talks of different criterias simultaneously and their relative importance for dairy wastewater treatment. This article intends to fill this gap by proposing a model considering environmental, tolerance and economic criteria for selection of macrophytes for dairy wastewater treatment. Analytic hierarchy process (AHP) was used to develop decision making model and for preliminary screening of macrophytes. Six commonly used macrophytes (Phragmites australis, Typha latifolia,Eichhornia crassipes Arundo donax, Lemna minor, Pistia stratiotes) were selected and ranked via model. We found the ranking in order of Typha latifolia> Phragmites australis> Arundo donax> Eichhornia crassipes > Lemna minor >Pistia stratiotes. Typha latifolia was the most preferred macrophyte and performed best in environmental as well as tolerance criteria. Further, it was found that ranking of plants were exactly same for tolerance and environmental. In other words, the plants which showed higher tolerance also showed better treatment performance in the exact same sequence in rankings.