Effects of Coagulant Dosage, Particle Size, and Settling Time on Pond Water Treatment with Cactus Pads and Watermelon Seeds

Abstract

Most Tanzanians who live in villages still struggle to get enough drinking water due to limited supply, so they use pond water for drinking and household purposes. Treatment of this water is crucial especially during the rainy season to reduce its turbidity. The performance of two natural coagulants (i.e., Cactus pads and watermelon seeds) was evaluated in their effectiveness in purifying pond water. The jar test method was used to analyze the effects of coagulant particle size, dosage, and settling time on the treatment of pond water. Attenuated Total Reflectance Fourier Transform Infrared spectroscopy (ATR-FTIR) was used for characterizing the functional groups of the coagulants. The presence of proteins and carboxylic acid groups in both coagulants demonstrates their potential for use in water purification.  The effectiveness of removing turbidity in pond water with Cactus and watermelon seed coagulants was determined to be 78.58% and 94.18%, respectively. For both coagulants, the longer the settling time, the more turbidity was removed. The study indicates that watermelon and cactus pads can be used as coagulants to replace synthetic coagulants.