Green technologies for cyanobacteria and natural organic matter water treatment using natural based products

Green technologies are environmentally friendly operations that limit the negative impacts of traditional industrial activities and can contribute to solving the challenge of sustainable water management. This work aims to develop a green water treatment sequence using a natural coagulant (Moringa oleifera) and a natural activated carbon (vegetable coconut palm) to remove Microcystis aeruginosa and natural organic matter in an integrated process. The proposed sequence, coagulation/flocculation/dissolved air flotation and activated carbon, is an eco-friendly and innovative option for water treatment managers, since it includes environmentally friendly products for the contaminant removal from water, replacing the traditional inorganic/synthetic coagulants and adsorbents. Results demonstrated that waters with concentrations as high as 150-200 μg/L of chlorophyll a and natural organic matter between 5 and 16 mg C/L presented removals higher than 80% for turbidity and chlorophyll a, 70-80% for dissolved organic matter and 80-90% for UV254nm. Moringa oleifera natural coagulant removed almost 80% of Microcystis aeruginosa cells in coagulation/flocculation/dissolved air flotation processes. The coconut palm activated carbon showed a high capacity to adsorb DOC from water with a maximum adsorbed capacity of 51.8 mg/g at equilibrium. The values obtained in treated water for the parameters measured are very encouraging, so this innovative integrated sequence may be used for improving water quality, benefiting human health and wellbeing.