Sunflower (Helianthus annuus) seeds as a natural coagulant for water turbidity treatment: assessment of efficacy and dosage

Abstract

Abstract The quality of river and borehole water fluctuates because of both agricultural and industrial pollutants. Surface runoff during the rainy seasons is high which promote increased turbidity levels in water sources, and this exerts pressure on the quality and usability of the water for domestic use. Unfortunately, most municipalities in developing countries are poor to afford conventional water treatment methods. This study assessed the use of natural coagulants extracted from sunflower seeds for turbidity treatment. Water samples were collected during summer, winter, and autumn from 10 randomly selected groundwater sources and three segments of the Mwerahari River in Buhera District, Zimbabwe. Results captured seasonal turbidity variations across the river segments and the boreholes. Summer season recorded the maximum average levels of turbidity (76 NTU) while autumn and winter recorded 38.7 NTU 36.7 NTU, respectively. Water turbidity levels were above the acceptable 5 NTU Standard Association of Zimbabwe and WHO. The maximum removal efficiency of turbidity was achieved at 80 min at the dose of 4 g/l. These results revealed that the removal efficiency of 95% with 4.6 NTU turbidity is a function of dose; removal efficiency increases as dose of coagulant increases. These results demonstrated that sunflower seed is an effective low-cost natural coagulant for turbidity water treatment.