The use of low quality water for irrigation in agriculture is common practise in many countries due to limited freshwater resources. Pathogens may contaminate vegetables when faeces polluted water is used for irrigation. A laboratory study was carried out to investigate the effect of a coagulant produced from seeds of the Moringa oleifera tree (MO) in reducing Cryptosporidium parvum oocysts and turbidity in wastewater. To a total of 5 x 12 glass jars containing 500 ml wastewater samples from a Danish treatment plant, 1.2 x 106 ± 1.2 x 105 oocysts L-1 were added. To half of the wastewater samples 8 ml L-1 of a 5% w/v MO seed extract was added, while the remaining wastewater samples were left untreated. The samples were stirred slowly for 20 min and subsequently left to settle for 15, 30, 45, 60 or 90 min, with six replicate glass jars representing each time point. In both treated and untreated wastewater, most oocysts settled within the first 15 min, while the sedimentation was negligible between 15 and 90 min. Nevertheless, MO seed extracts were effective in reducing the number of C. parvum oocysts significantly (p=0.026) by 38% in the interval 15 to 90 min as compared to a 0.02% reduction in the untreated wastewater. Furthermore, the number of oocysts L-1 was significantly (p0.005) lower in the treated wastewater at all 5 sampling times compared to untreated wastewater. The turbidity was reduced to 9.8 ± 1.8 NTU (i.e. 95% reduction) in the treated water, which was significantly (p0.0001) lower than the lowest turbidity values of 57.7 ± 4.2 (i.e. 72% reduction) seen in the untreated water. MO seeds are readily available in many tropical countries where the tree is common, and our results document that the seed extract may be used by farmers for treatment of different types of surface water. Yet, the study did not succeed in removing all oocysts from the wastewater after treatment, which was probably caused by an imbalance between the relative concentration of oocysts and MO seed extract with more oocysts present than the seed extract could adhere to. However, treatment of wastewater with MO seed extract significantly improved the water quality with regard to number of oocysts present and turbidity of the water. Further experiments with water samples containing fewer C. parvum oocysts are needed to establish whether MO seed extract can be used to effectively treat and obtain safe water free of C. parvum oocysts as well as other protozoan parasites.
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机译：由于淡水资源有限，在许多国家中，在农业中使用劣质水灌溉是很普遍的做法。当使用粪便污染的水灌溉时，病原体可能污染蔬菜。进行了一项实验室研究，以研究由辣木树（MO）种子产生的混凝剂对减少小隐隐孢子虫卵囊和废水中浊度的影响。向总共5个12个装有500毫升丹麦处理厂废水样品的玻璃罐中，添加1.2 x 106±1.2 x 105个卵囊L-1。向一半的废水样品中添加8 ml L-1的5％w / v MO种子提取物，而其余废水样品则不予处理。将样品缓慢搅拌20分钟，然后静置15、30、45、60或90分钟，每个时间点放置六个重复的玻璃瓶。在经过处理和未经处理的废水中，大多数卵囊都在最初的15分钟内沉淀下来，而在15至90分钟之间的沉淀作用可以忽略不计。然而，MO种子提取物可在15到90分钟的间隔内有效地将小球囊虫卵囊的数量显着减少（p = 0.026）38％，而未经处理的废水则减少0.02％。此外，与未处理废水相比，在所有5个采样时间中，处理后废水中的卵囊L-1数量均显着降低（p <0.005）。处理后的水中的浊度降低到9.8±1.8 NTU（即降低95％），这比未处理水中的最低浊度值57.7±4.2（即降低72％）要低得多（p <0.0001）。 MO种子在许多常见树木的热带国家很容易获得，我们的结果表明，农民可以使用种子提取物来处理不同类型的地表水。然而，该研究未能成功去除处理后的废水中的所有卵囊，这可能是由于卵囊与MO种子提取物的相对浓度之间的不平衡所致，存在的卵囊数量超过了种子提取物所能粘附的数量。然而，就存在的卵囊数量和水的浊度而言，用MO种子提取物处理废水显着改善了水质。需要用含有较少的小球藻卵囊的水样品进行进一步的实验，以确定是否可以将MO种子提取物用于有效处理和获得不含小球藻卵囊以及其他原生动物寄生虫的安全水。
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