Development of point of use water purification technology using Moringa seed coupled with Scoria as an alternative coagulantionfilteration media.

Abstract

The coagulation-flocculation, filtration and adsorption behavior of some low-cost adsorbents such as peanut husk, charcoal, fly ash, Volcanic ash soil and natural zeolite materials have been studied as treatment agents to remove undesirable PO4-3, Fe+3 and F- ions and other heavy metals from water by adding significant alternatives to the water purification technology. Chronic exposure to high fluoride (>1.5) leads to dental and skeletal fluorosis while high concentration of phosphate (i.e. >1 mg/l) in drinking water cause digestive problems and interfere with coagulation in water treatment plants whereas high concentration of iron (>0.3mg/l) has the potential of generating bad taste to the drinking water. This study aimed at developing point of use drinking water purification technology using Moringa Olifera seed (MOs) coupled with Virgin Scoria (VSco) as coagulant and filter media. The physicochemical parameters considered to evaluate the efficiency of the technology were turbidity, TDS, COD, Color and PO4-3, Fe+3 and F-. The physicochemical analysis of water sample was done before and after both treatment, using standard methods. The sampling and analytical efforts was focused on two major phases (1) The coagulation flocculation through jar test experiments using MOs and (2) the filtration process through VSco filter media. Jar test experiments was conducted under batch experiment as a function of solution pH, contact time, adsorbent dosage and adsorbate concentration to obtain maximum operation quality and optimal dose range at the standardized agitation speed. Based on this, the physicochemical analysis indicated that turbidity from (150-8NTU), PO4-3(20-5.95mg/l), Fe+3 (7- 2.93mg/l) and F- (9-2.83mg/l) reduction was achieved at 35mL/L of Optimum Moringa dose within 6.5-7.5pH range. Then VSco filtration was conducted after jar test under small column experiment as a function of contact time (0, 2, 4hrs). The VSco removal capacity showed that the removal of turbidity from (8-2.54NTU), PO4-3(5.95-1.07mg/l), Fe+3 (2.93-0.43mg/l) and F- (2.83- 1.94mg/l) were attained after 4hr detention time. Generally, the percent removal of turbidity, PO4-3, Fe+3 and F- increases remarkably with increasing of their initial concentration. At an initial concentration of turbidity (150NTU), PO4-3 (20mg/l), Fe+3 (7mg/l) and F- (9mg/l), the removal efficiency were 98%, 84%, 85% and 60% respectively. However, the removal capacity of VSco decreases with increasing the time of operation unless it was washed from clogging particulate matter or replaced by new scoria. The batches experiment (using positively charged protein of MOs) suggested that the removal behavior was mainly controlled by cation exchange and typically displays characteristics of charge neutralization. Therefore, we recommend VSco -Moringa as an economic, efficient and simple Point of Use drinking water treatment technology