USING NATIVE AFRICAN SPECIES TO SOLVE AFRICAN WASTEWATER CHALLENGES: - - PowerPoint PPT Presentation

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USING NATIVE AFRICAN SPECIES TO SOLVE AFRICAN WASTEWATER CHALLENGES: AN IN-DEPTH STUDY OF TWO VETIVER GRASS SPECIES

Effiom Oku1, Kwabena Asubonteng1, Catherine Nnamani2, Itam Michael3 and Paul Truong3

1United Nations University Institute for Natural resources in Africa, Ghana

& Coordinator, Vetiver Network, Ghana and Nigeria.

2 Ebonyi State University, Nigeria 3The Vetiver Network International (TVNI), Technical Director and Director for

Asia and Oceania, Brisbane, Australia

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United Nations University Institute for Natural Resources in Africa

What we kn know and the chall llenges

• Wastewater management challenge is a

global issue (Plate 1&2) (UNEP, 2010 and Kumar 2011).

• Most industrial effluents in Sub Sahara

Africa are discharged into environment untreated.

• Settling pond popular in wastewater

management in Africa (Nikiema et al., 2013)

• Conventional treatment technologies are

very limited and climate change is impacting.

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Plate 1. Water drainage way in a city in Nigeria Plate 2. An urban vegetable farm irrigated using water from Plate 1.

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What we know and the challenge

• South Indian spp is effective in

wastewater treatment (Truong and Hart, 2001; Truong, et al., 2006)

• Three spp of vetiver grass are known

(Truong et al., 2006).

• All known spp of vetiver have different

potentials, some for erosion control as in plate 3. (Truong et al., 2008).

• Use of vetiver in Africa is not common

and still at its infancy (Babalola, et al., 2007: Oku, 2011).

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Plate 3 shows Chrysopogon zizanioides (A) and Chrysopogon nemoralis (B)

(Source:www.vetiver.org) A B

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What we d do not know

• The effectiveness of African spp in removing contaminants

in wastewater. Objective

• To study the effectiveness of African spp in wastewater

treatment and compare with well known South Indian spp.

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Methodology

• Effluents collected from quarry site,

fertilizer company and untreated public dump site.

• Vetiver raised hydroponically for root

and shoot establishment.

• Floating raft with established vetiver

immersed in effluents as in Plate 4 (Truong et al., 2008).

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Plate 4 Set-up with South Indian spp (4A) and African spp (4B) floating in effluent from fertilizer company.

4A 4B

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Methodology

• Pre-and post-treatment contaminants determined included,

heavy metals, pH, BOD, COD (FEPA,1991; APHA, 2001; WHO, 1989; and Udo et al., 2011).

• Treated effluents collected after 2, 4 and 6 days for

laboratory analysis.

• Contaminant levels compared with safe levels by FAO/WHO.

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Results and Discussion

PTL = pre-treatment, contaminant levels, DAT = days after treatment; AL = allowable limit

Fig 1: Pre level and post-treatment, nitrate removal rate in public dump untreated leachate in Abakaliki, Nigeria.

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20 40 60 80 100 120 PTL 2DAT 4DAT 6DAT

100% 55% 58% 59% 55% 59% 63% Nitrate in leachate (mg l-1) African spp South Indian spp

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PTL = pre-treatment, contaminant levels, DAT = days after treatment; AL = allowable limit

Fig 2: Pre-level and post-treatment phosphate removal rate in public dump untreated leachate in Abakaliki, Nigeria.

10 20 30 40 50 60 70 80 90 100

PTL 2DAT 4DAT 6DAT 100% 50% 72% 79% 43% 55% 56%

Phosphate in leachate (mg l-1) African spp South Indian spp

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0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18 0.2

PTL 2DAT 4DAT 6DAT Cadmium in ferilizer effluent (mg l-1)

African spp South Indian spp

PTL = pre-treatment, contaminant levels, DAT = days after treatment; AL = allowable limit

Fig 3: Pre level and post-treatment, Cd removal rate in fertilizer industry effluent in Abakaliki, Nigeria.

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PTL = pre-treatment, contaminant levels, DAT = days after treatment; AL = allowable limit

Fig 4: Pre and post-treatment, pH levels in quarry effluent collected in a city in Abakaliki, Nigeria. 2 4 6 8 10 12 14 PTL 2DAT 4DAT 6DAT pH of quarry effluent (mg l-1)

African spp South Indian spp

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0.05 0.1 0.15 0.2 0.25 0.3

PTL 2DAT 4DAT 6DAT

100% 80% 83% 83%

13% 77% 97%

Lead in quarry effluent (mg l-1) African spp South Indian spp PTL = pre-treatment, contaminant levels, DAT = days after treatment; AL = allowable limit

Fig 5: Pre and post-treatment, Pb levels in quarry effluent in Abakaliki, Nigeria.

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Conclusion

• African spp of vetiver grass is as good as South Indian spp.
• African spp was more effective in removing phosphate

while, South Indian spp was more effective on nitrate.

• Both spp improved pH.
• Both spp should be combined where possible for maximum

industrial benefit.

• Africa can rely on its endemic spp for commercial and micro

scale wastewater treatment.

• Production of hybrid of the two spp is needed.

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Acknowledgement

First author acknowledges the African Women in Agricultural Research and Development (AWARD) for partly sponsoring this trip to enable him present this paper at this conference.

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Thank you Questions!!!

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