Effect of Vetiver on refuse-dump leachates

When refuse-dump leachates were treated with C. zizanioides, the following changes were recorded: pH was slightly changed but increased by 15 % in day 4. BOD and COD decreased continuously from day 2 to day 6 by an average of 62 %. NO3- and PO43- decreased continuously from day 2 to day 6 with an average of 58 % and 51 % respectively (Figure 7). The highest reduction of CN-, Fe, and Co occurred in day 4 (84 %, 94 % and 100 % respectively).  Zn and Co were below detectable limits in day 6.
When treated with C. nigritanus, refuse dump leachates were mineralised as follows: pH relatively unchanged. BOD, COD, NO3-, and PO43- showed continuous decrease from day 2 to day 6. CN-, Fe and Co showed slight changes in day 2
but rapid reduction in day 4 (91 %, 100 %, and 100 % respectively). Zn decreased rapidly in day 2 and was below detectable limits in day 4.  Fe and Co were also below detectable limits in day 6 (Figure 8).
T-cal values obtained from these parameters when treated with C. zizanioides and C. nigritanus are as follows: pH (2.115), BOD (1.732), COD (-0.143), NO3- (1.000), PO43- (-3.174), CN- (-0.192), Fe (0.226), and Co (-1.000) (Table 5).


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Effect of Vetiver on Abattoir Effluent 

Abattoir effluent, when treated with C. zizanioides, yielded the following results: pH increased slightly in day 4 (24 %), but reduced in day 6 (9 %). BOD, COD, NO3-, PO43-, CN-, Zn, Fe and Mn reduced continuously from day 2 (Figure 9) to day 6 with an average of 70%, 70%, 69%, 63 %, 80 %, 77 %, 76 %, 69 % respectively. Zn was below detection in day 4. Highest reduction for Mn occurred in day 4.
When treated with C. nigritanus, the following results were obtained: pH was unchanged in day 2, but reduced in day 4 and 6 with an average reduction of 11%. BOD, COD, PO43-, CN-, Zn, Fe and Mn decreased from day 2 to day 6 with an average reduction of 71 %, 78 %, 65 %, 82 %, 78 %, 70 % and 71 % respectively. NO3- decreased in day 2 and remained relatively unchanged until day 6. A slight change in day 2 and rapid reduction in day 4 (100 %) was observed in Mn. Zn and Fe were below detectable limits in day 4, while, Mn reappeared in day 6 (Figure 10).


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T-cal values obtained from these parameters when treated with C. zizanioides and C. nigritanus are as follows: pH (0.475), BOD (-0.655), COD (-0.615), NO3- (2.638), PO43- (-0.363), CN- (-1.890), Zn (-1.000), Fe (-0.832), and Mn (-0.611) (Table 5).