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The effects of Moringa lieifera seed powder on turbidity and sedimentation of Cryptosporidium spp. in wastewater

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Abstract

The use of different types of wastewater for irrigation in agriculture is common practise in many countries due to limited freshwater freshwater resources. Contamination of fruits and vegetables with pathogenic microorganisms, including Cryptosporidium spp., may occur when the irrigation water or water used for postharvest washing of the produce is contaminated. A laboratory study was carried out to investigate the effect of a coagulant from the seeds of Moringa oleifera (MO) in reducing Cryptosporidium parvum oocysts and turbidity in Danish wastewater. To each of five time points, 12 replicates of 500 ml wastewater samples were added 1.2 9 105 oocysts per litre. Half of the replicates were added 4 ml/l of a 5% w/v MO extract, while the other half was left untreated. The samples were stirred slowly for 20 min and subsequently left to sediment for 15, 30, 45, 60 or 90 min. In wastewater from a Danish treatment plant MO extracts were effective in reducing the number of Cryptosporidium oocysts by 93 3.2% after 90 min of sedimentation and the turbidity to 9.8 1.8 NTU, corresponding to a turbidity removal of 95%. MO is readily available in many tropical countries and can be used by farmers for water treatment. Yet, in this study, a large number of oocysts remained in the wastewater after treatment. This was likely because the proportion of oocysts and active component from MO extract was imbalanced, with more oocysts added than the MO extract could adhere to. Additional experiments with water samples containing fewer and/ or naturally occurring Cryptosporidium oocysts are needed to establish whether MO extract can be used to effectively treat and obtain safe water free of Cryptosporidium oocysts.