Use of Moringa oleifera seed extracts to polish effluents from natural systems treating faecal sludge

Abstract

The removal of pathogens in irrigation water is of great importance in developing countries. Indeed, wastewater generally reused for agriculture in countries such as Cameroon is associated with health and environmental concerns. Recent studies have shown a strong disinfectant action of the natural coagulant from the seeds of Moringa oleifera. These findings have raised the question whether or not they can be used to polish effluents from natural systems treating faecal sludge. This paper deals with trials carried out to investigate the effect of these extracts in reducing faecal indicators from initially treated faecal sludge leachate. Bacteriological and physico-chemical parameters were used to determine the optimum conditions and assess treatment efficacy. Settling time of 3 h at a concentration of extracts between 267 and 333 mg/L permitted to reduce Escherichia coli and faecal coliforms from 4.85 to 3.92 ulog (86.74%) and from 5.75 to 4.87 ulog (86.39%) respectively with 1 ulog equal to 90%. For the same settling time and at a concentration of 333 mg/L, faecal streptococci were removed from 6.40 to 5.67 ulog (81.33%). This level of removal suggests that this natural coagulant cannot be used alone for disinfection of heavily loaded effluent. Further investigations are therefore still needed to fulfil the Cameroon and WHO guidelines for safe reuse in agriculture.

Kinetic Modeling of Escherichia coli Removal Mechanisms in Faecal Sludge on Unplanted Sand-Drying Beds Using Moringa Oleifera as a Conditioner

“…15). This decrease in bacteria counts was statistically significant (p=0.0003 at α=0.05), attributed to the antibacterial effect of MO introduced to FS, retaining the dead bacteria in the solid composition (Ngandjui et al, 2019). Silva et al (2013) further corroborated these findings, highlighting the strong disinfectant properties of the coagulant derived from the seed of M. Oleifera.…”

Research on Moringa (Moringa oleifera Lam.) in Africa

“…Indeed, moringa was used in the treatment of sewage sludges, wastewater, effluents, and different types of industrial wastes [ 111 , 137 , 215 , 219 , 229 , 246 , 311 , 391 ]. Studies in this respect, exploiting the potential of M. oleifera seeds as coagulants/flocculants, were carried out in Algeria [ 109 , 111 ], Kenya [ 229 ], Tunisia [ 391 ], Cameroon [ 137 , 140 ], Ghana [ 201 , 215 , 220 ], and Malawi [ 246 ]. Kilingo et al [ 229 ] pointed out that the use of moringa is “ a low-cost sewage treatment technology suitable for poor areas ” (p. 36589).…”

Water reclamation and reuse

“…A study in Cameroon showed that using 333 mg/L Moringa oleifera seed extracts as a coagulant in a vertical flow constructed wetland for the treatment of raw fecal sludge was insufficient in reducing Escherichia coli (86.74%), fecal coliforms (86.39%), and fecal streptococci (81.33%), and the effluent did not meet the Cameroon and World Health Organization (WHO) guidelines for safe wastewater reuse in agriculture and concluded that more studies are needed (Tchangoue et al, 2019).…”