Using Strychnos potatorum Seeds as a Natural Coagulant in Flood Affected Areas of Bangladesh

Abstract

The aim of this research is to find and show the effectiveness of Strychnos potatorum seeds as a natural coagulant for purifying and producing potable water in flood prone rural areas of Bangladesh. Strychnos potatorum, locally called ‘Nirmali’ or ‘Nirmala’, is a natural coagulant which was used in the Indian Subcontinent during the stone ages but has slowly become forgotten. This research was carried out to reintroduce this ancient coagulant and find its effectiveness during floods, particularly in Bangladesh. As a riverine country prone to flooding and devoid of quality water purification systems, coagulants like alum and ferric sulfates are often used although these synthetic chemicals have been found producing DBPs in water which are associated with certain health hazards. And so, replacing these synthetic chemicals with a natural coagulant such as Strychnos potatorum seeds in flood prone rural areas will be a beneficial and cheap water purification system for the populace. To prove the effectiveness, various tests (pH, HCO3 , Cl, Na, K, Na2 CO3 , NTU, TCU, Total Hardness (CaCO3 ), BOD, COD, CFU) were carried out across flood prone areas around Dhaleshwari River (Nagarpur, Tangail) to find out whether Strychnos potatorum seeds will be able to replace the commonly used chemical coagulants and provide drinkable water to the flood affected people or not. Experiments were carried out to find the optimal dosage, flocculation and settling time and reusability of the Strychnos potatorum seeds. The reason behind selecting this region for research purpose is that the soil and tree characteristics of this area is perfect for planting and growing Strychnos potatorum trees and they can be easily distributed among the populace when disaster hits. The test results proved that the parameters comply with the WHO Drinking Water Standards. So, our test results have shown that the Strychnos potatorum seeds are highly effective when it is used to treat water in these flood prone areas. And our initial estimation is Strychnos potatorum will provide a remarkably successful and high yield in these targeted areas. According to our calculations and research it will cost only 0.18 dollars or 18 cents versus 0.25 dollars for most conventional method (Potash Alum) for per liter of water treatment. As the project will require planting Strychnos potatorum trees, the project will improve the environment and distributing them to flood affected populace will increase the peoples’ awareness regarding tree plantation and drinking safe water. Also, this project will act as a replacement to the synthetic chemical coagulants used in the flood affected rural areas of Bangladesh and replacing those synthetic chemical coagulants with biodegradable Strychnos potatorum will be good for the environment as a whole there will be less chemical waste. This project will strengthen the water security of Bangladesh as well as play an important role in stopping the climate change and its adversities.