ASSESSMENT OF WASTE WATER TREATMENT IN CANAANLAND, OTA, OGUN STATE, NIGERIA.

S. A. Isiorho,1 and F. A. Oginni2 1. Department of Geosciences, Indiana University – Purdue University, Ft. Wayne (IPFW),

Fort Wayne, IN 46805, USA. E-mail: isiorho@ipfw.edu 2. Department of Civil Engineering, Covenant University, Km. 10, Idiroko Road,

P.M.B. 1023, Ota, Ogun State, Nigeria. E-mail: kafnog@gmail.com

Canaanland in Ota, Ogun State, Nigeria is the home of the Living Faith Tabernacle, the largest Church Auditorium in the world and that of the Covenant University. The effluent of the treated waste water in this community is discharged into a gully that drains into River Iju (also known as Atuara), which is used as a source of drinking water and also provides food in form of fish for hundreds of thousands of people downstream. This eventually enters the lagoon, some 60km away. Evaluation of the effectiveness and adequacy of the wastewater treatment facility in place is being carried out in order to improve sanitation within this watershed, thereby alleviating environmental challenges in this coastal region of Nigeria. Eight boreholes drilled to depths of approximately 54m serve the Covenant University community, the combination of which produces a water requirement of 4,120m3 per day on the campus with about 80% being returned as waste water. Waste water is gravity drained to the southwest portion of the campus where the solid is removed and the liquid is allowed to flow through six sets of constructed wetlands, each with four chambers. Within each chamber are water hyacinth plants put in place to remove nutrients from the waster water. A quick survey of the facility shows the system to be effective in reducing and removing solids and dissolved solids from the waste water. The pH ranged between 6.6 and 6.8, conductivity from 530 to 600, and total dissolved solids (TDS) ranged from 360 – 400 ppm. The data obtained indicate that some modifications need to be made as the waste water treatment system is not very efficient in reducing the amount of TDS and nutrients. The flow rate is considered to be very high from cell to cell, thereby not allowing time for the plants and microbes to reduce the TDS. It is suggested that some method be devised to slow down the flow rate to allow the plants and microbes to work on reducing the TDS. Other parameters such as DO, E. Coli. Nitrate and Phosphates were also considered. Keywords: Sewage Wastewater Treatment Influent Effluent Wetland Water hyacinth 1.0 INTRODUCTION The major concern of stakeholders in the development of hydrological basins is the conservation of the ecosystem. Canaan land is located within latitude 60 40’ North and longitude 3010’ East. It is on an area of 236 hectares in the Ado-Odo/Ota Local Government area of Ogun State. Ota is the Industrial nerve centre of the State. Faith Tabernacle which is the largest Church Auditorium in the world belonging to the Living Faith Ministry Worldwide is resident in Canaan land. Covenant University is also located in Canaan land. The hydrological basin to which Canaan land

CA CB

CC

CD CA

CE CF

Manhole

Underground Concrete Septic Tank

Daniel Hall Road

To R. Atuara

300 dia Pipework

Gate Valve Surface Water Concrete Tank

Fig. 2: Layout of Canaan Land Sewage Treatment Plant

WWTP

Fig. 1: Covenant University Map Map

belongs is in the Iju river basin. Activities downstream of this basin include fishing, farming, commercial, educational institutional and industrial activities. Sewage in Canaan land is discharged for treatment through an anerobic septic tank in the sewage treatment plant. Effluent from this tank is treated by passing it through a series of constructed wetland to discharge into a canal which empties into River Atuara, a tributary to River Iju. The effluent from the constructed wetland series in Canaanland is expected to improve or at best maintain a fruitful basin. 2.0 Sewage and Waste water Treatment Facility and Treatment Process in Canaan land. Generally, septic tank – soak away systems are provided for most of the buildings in Canaan land to take care of their environmental sewage sanitation requirements. Septic tanks are sufficient for the treatment of house hold wastes. This can not be the case for the Church premises as it is to take care of the sanitation needs of more than 50,000 worshippers at least every Sunday. The septic tank arrangement is not suitable for a University community because of its large population. Even the Imhoff Tank which is an advance modification of the septic tank is not adequate for this exercise. Oginni, (2008), indicated that the Imhoff tanks are best suited to small municipalities and large institutions where the tributary population is 5,000 or less, and a greater degree of treatment is not needed. Obviously, Covenant University community, flying towards World-Class University status and with a population of about 10,000, can only consider the use of sewage treatment plant in dealing with its environmental sanitation requirements. The treatment plant in its campus had been so designed to handle sewage from the Church premises also. Sewage treatment site in Canaan land is located at the westernmost wing of the Covenant University campus remote but opposite to Daniel Hall. This location is indicated as WWTP in Fig. 1. The waste treatment plant was initially for both solid and liquid wastes. They were separated after some years. Faeces and toilet wastes are treated at the waste treatment plant. The

treatment is a biological process. Layout of the treatment plant is as sketched in Fig.2. The effluent is discharged through the concrete lined open channel leading to the canal where it is disposed into River Atuara. Sewage Disposal Tankers evacuate sewage from the Toilets within the Church premises every week. A total of between 10 and 15 tanker trips are recorded per week. Each Disposal Tanker has a capacity of 10,000litres. It can therefore be stated that some 12,000 to 18,000 litres of sewage is generated every week within the Church premises. Wastewater generated per day by the University community was considered based on the rate of water supplied per day on the campus. There are a total of 8 boreholes in operation on the campus together with 4 service reservoirs. Although there are no data for water consumption rate, the rate of refilling of the reservoirs was given as 4 refills per day. The capacities of the tanks put together was given as 1,054,000 litres on daily basis, thus the water consumed/day can be estimated as 4,216m3/day. It should be noted that this consumption included water use in the laboratories, workshops, gardening and other uses such as on going construction works on the campus. Of this 4,216m3/day water consumption, 80% is considered to return as wastewater. Maintaining wetland in urbanized areas has a lot of considerations. Isiorho, (2006) discussed challenges of maintaining urban wetlands. Sewage is discharged into existing Inspection Chambers around the sloppy road to Daniel Hall area. It will then flow by gravity into the underground Septic tank, where complex organic materials are anaerobically decomposed to simple organic molecules and fermentation gases. When the build up gets to a specific level it begins to flow into the constructed wetland by gravity. The operating principle is the same as that of the septic tank flowing into the soak-away chamber. The wastewater flows into the constructed wetlands are the main focus of this paper. 3.0 Wastewater Treatment Assessment Criteria It is the biological process in the constructed wetland that need be evaluated for its adequacy and efficiences. The quality of the wastewater is to be monitored from the effluent discharged into the constructed wetland through the various chambers up to its point of discharge into the canal. In order to establish the adequacy of the treatment system, the canal to which the effluent is to be discharged should also be monitored before and after the discharge points. Since water hyacinth, (E. crassipens) is used in the constructed wetland, its responses and effectiveness in this context will be compared to expected surface water quality. Surface water quality standards are obtainable in the literature. Hammer, (1977) classified the surface water criteria for public water supplies into the following characteristics: (i) physical (ii) microbiological (iii) Inorganic chemicals (iv) organic chemicals (v) radiactivity The water quality parameters as indicated by MoDNR, (2008) gave a comprehensive list of 22 different water quality parameters. These are Acidity, Alkalinity, Ammonia, BOD, CBOD, COD, Conductivity, Dissolved Oxygen (DO), Fecal Coliform, Hardness, Metals, Nitrate, Nitrite, Nitrogen as Total Kjeldahl ((Organic Nitrogen and Ammonia ), TKN), Nitrogen, Nitrogen as Ammonia, Phosphorus, pH, Total Solids, Temperature, and Turbidity. Some of the parameters are related to themselves. For instance record of pH can give insight into acidity or alkalinity. Ammonia, Nitrate, Nitrite, TKN, Nitrogen and Nitrogen as Ammonia are all Nitrogen related parameters. In this paper, physical, chemical and microbiological parameters are considered. The specific qualities and their variations within the constructed wetland stated below are considered for analyses. (i) pH (ii) Total Dissolved Solids (TDS) (iii) Conductivity (iv) Coliform colonies counts (v) Nitrogen and (vi) Nitrates

4.0 Sampling and Laboratory Tests 3 sets of sampling / investigations were carried out for three sets of wastewater quality parameters. In – situ tests of pH, Total Dissolved Solids and Conductivity were carried out for the constructed wetland series at different spots / locations. Results are presented in Table 1. Temperature during these investigations was 280C throughout the exercise. Samples were taken from each cell within the first chamber, CA to reveal the possibility of variation within chambers. Eleven sampling points were identified for the bacteriological and chemical tests. Eight of these points were in the constructed wetland chambers. Two different sampling points per chamber, at entrance and exit from chambers A and B were considered. Results on these were to reveal any variation within the four cells in each chamber. Sampling points G, H and I were for the effluent discharge channel point, a location on the canal at some 300m upstream of the discharge point and 300m downstream of same discharge point respectively. This is to enable us assess the effect of the treated wastewater on the water flow in the canal leading to River Atuara.

TABLE 1: RESULTS OF pH, TOTAL DISSOLVED SOLIDS AND CONDUCTIVITY

SPOT

DESCRIPTION PARAMETER

REMARKS TOTAL DISSOLVED SOLIDS, TDS (ppm)

CONDUCTIVITY (milliliters/sec.)

pH

1 Influent Tank 397 610 6.8 2 Chamber CA – Cell 1 390 580 6.8 3 Chamber CA – Cell 2 400 600 6.8 Entrance to Cell2 4 Chamber CA – Cell 2 390 580 6.8 Mid-way 5 Chamber CA – Cell 3 400 590 6.75 Entrance to Cell3 6 Chamber CA – Cell 3 400 590 6.75 Exit from Cell 3 7 Chamber CB – Cell 4 370 540 6.75 8 Chamber CC – Cell 4 380 570 6.75 Exit 9 Chamber CD – Cell 4 380 560 6.7 Exit

10 Chamber CE – Cell 4 370 550 6.75 Exit 11 Chamber CF – Cell 4 365 543 6.75 Exit 12 Effluent channel 355 530 6.8 2.5m away

In order to carryout sampling for bacteriological quality and chemical characteristics analyses, 250ml conical flasks were sterilized preparatory to collection of wastewater samples from various chambers and cells of the constructed wetlands. The samples were forced through a filter and incubated at a specific temperature for specific time. The resulting colonies that formed during the incubation were counted and recorded as the number of colony producing unit per 100ml of water. Standard Methods for the examination of water & wastewater were adhered to. Presumptive tests for coliform was first undertaken. Most Probable Number of coliform in 100ml of water, MPN/100ml, was obtained. The Table of Most Probable Number was used. Results for the various samples are shown in Table 2. After inoculation of positive plates, from presumptive test at 370 C for 24 hours on Eosin methylene blue agar, a bluish black with a metallic sheen was observed. This serves as a confirmatory test for Coliform. A complete test is carried out on

Colonies from confirmatory test result above by inoculating in a tube of lactose broth with inverted Durham tube and nutrient agar sealant. This was incubated at 440C for 24hrs. Explanations on the confirmatory and complete tests are that (i) if lactose broth culture produces acid and gas, it implies Positive i.e. Positive test that E.coli is present to the degrees shown in Table 2. If Sealant culture gives a Gram negative, non sporulating bacilli, this confirms that Coliform (E. Coli.) is present. This is used to test the quality of water. Standard procedures are presented by Standard Methods, (1998) Feng et al., (2002) . TABLE 2: RESULTS OF PRESUMPTIVE TEST FOR COLIFORM MOST PROBABLE NUMBER OF COLIFORM IN 100ml OF WATER S/NO SAMPLE MPN / 100ml REMARKS

(cfu/ml) Obtained from the MPN Table 1 A1 1,600 Entrance into Chamber A, CA 2 A2 1,600 20 3 B1 550 20 4 B2 250 40 5 C 275 60 6 D 250 80 7 E 50 100 8 F 13 120 9 G - Effluent channel

10 H - 300m Upstream Effluent Discharge Point 11 I - 300m Downstream Effluent Discharge Point

The various media applied for different parameters put to test for bacteriological analyses were MacConkey Agar for Coliform; Mannitol Salt Agar for Staphylococcus; Brilliant Green Agar for Salmonella; Salmonella Shigella Agar for Salmonella and Shigella. Others are Nutrient Agar for Total Viable Count, TVC; and Potato DextrosebAgar for Fungi, mainly Yeast. Results obtained are presented in Table 3. TABLE 3: TREATMENTS AND RESULTS OF BACTERIOLOGICAL ANALYSES

S/No SAMPLES/ MEDIA

(102)

MacConkey Agar/Coliform

(cfu/ml)*

Mannitol Salt Agar (cfu/ml)

Brilliant Green Agar

(cfu/ml)

Salmonella Shigella Agar

(cfu/ml)

Nutrient Agar

(cfu/ml)

Potato Dextrose Agar

(cfu/ml) Colifom Staphyloco

ccus Salmonella Salmonella and

Shigella Total Viable Count (TVC)

Fungi (Mainly Yeast)

1 A1 120 108 132 136 143 52 2 A2 108 102 121 104 131 48 3 B1 98 96 117 101 115 32 4 B2 95 78 108 89 102 26 5 C 62 49 102 70 99 28 6 D 55 42 86 66 78 19 7 E 40 27 81 57 60 14 8 F 18 22 63 41 48 09 9 G - 12 21 09 19 06 10 H - 16 36 13 25 11

11 I - 09 07 04 10 04 *cfu/ml is colony unit per milliliter

Testing for the Nitrogen and Nitrates concentrations in the water sample were undertaken using the Palintest photometer following the standard kits and procedures. In this method, nitrate is first reduced to nitrite, which is determined by a diazonium reaction with sulphanilic acid in the presence of N-(1-naphthyl)-ethylene diamine to form a reddish dye. This reduction stage is carried out using the unique zinc-based Nitratest powder and Nitratest tablet which aids rapid flocculation after a one minute contact period. The intensity of the colour produced in the test is proportional to that of the nitrate concentration and is measured using the photometer. Measurements were replicated and averages were taken. The resulting concentrations are presented in Table 4.

TABLE 4: NITROGEN AND NITRATE CONCENTRATIONS

5.0 RESULTS AND DISCUSSIONS Total Dissolved Solids, (TDS) averaged 397ppm at the influent into the constructed wetland. This value reduced to 390ppm in the first cell of the first chamber. A variability of 21/2% in the TDS was observed within the cells of the first chamber. A chamber in the constructed wetland is 20m long x 6m wide. The second chamber, CB dropped to 370ppm to rise to 380ppm in the third chamber, CC. TDS then reduced gradually until the last Chamber. The TDS reduced by 8% within the wetland. This trend is shown in Fig. 3. and continued to the effluent channel, point G. Conductivity ranged form 600ml/sec to 543ml/sec. as shown in Fig. 3. The reduction rate was 10% only. This trend is similar to that of the TDS. This portrays the system as inefficient. The residing time of the material within the wetland will need to be improved in order to have more time to allow the hyacinth plant and microbes enough time to reduce the TDS. The pH over the entire range remained constant at 6.8. Generally, a range of 6.5 to 9.5 is tolerable. The pH of 6.8 is considered low and may be due to high levels of free CO2 in the water samples (Okokwo et al., 2008). Results of the presumptive test for coliform indicate that the most probable number of coliform in100ml of this wastewater in the first chamber is 1600cfu/100ml. This value did not vary within the chamber but dropped sharply to 550cfu at the entrance to second chamber, CB with a further drop of 250cfu within the 20m chamber length. A reduction trend in this parameter is as shown in

S/NO

SAMPLES

CONCENTRATION. (mg/l) REMARKS NITROGEN, N NITRATE, NO3 -

1 A1 0.268 1.177 2 A2 0.258 1.135 3 B1 0.541 2.378 4 B2 0.733 3.223 5 C 0.513 2.255 6 D 0.845 3.718 7 E 0.778 3.421 8 F 0.615 2.706 9 G 0.415 1.826

10 H 0.305 1.340 11 I 0.270 1.188

FIG. 6: PRESENT CONDITION OF THE FIRST AND SECOND CELLS OF CHAMBER A, CA

CHAMBER CA, CELL 2 CHAMBER CA, CELL 1

Fig.5: Variation of Isolated Bacteria Species, TVC and Fungi Within The Wetland

0

20

40

60

80

100

120

140

160

0 20 40 60 80 100 120 140

Distance From Influent Along the Wetland Series

Col

ony

Uni

t Per

ml (

cfu/

ml)

Coliform StaphylococcusSalmonella Salmonella and ShigellaTotal Viable Count, (TVC) Fungi (Mainly Yeast)

Fig. 4. The MPN recorded for sample G, in the effluent channel is zero. Zero figures were also recorded for samples taken 300m before and after effluent discharge into the canal. This shows an evidence of non pollution of the hydrological basin by this wastewater treatment plant.

Fig. 4: Variation of MPN Along the Wetland

0

200

400

600

800

1,000

1,200

1,400

1,600

1,800

0 20 40 60 80 100 120 140

Distance from Influent Along the Wetland Series

Mos

t Pro

babl

e N

o of

Col

iform

/100

ml

From the results and trend shown in Fig. 4, we are recommending that an additional chamber to the existing series of constructed wetland through which we envisage an MPN of zero to be achieved within the constructed wetland. A second additional chamber is expected to totally remove the contaminants.

Results of the bacteriological analyses are shown graphically in Fig. 5. Coliform counts reduced from 120cfu/ml at the influent spot by the first chamber to 18cfu/ml by the last chamber, CF. Similarly staphylococcus, salmonella, salmonella and shigella, bacteria counts followed the same trend as the coliform presentation. The same trend was obtained for the Total Viable Count and Fungi. TVC at the last chamber CF was 48cfu/ml, which is below the 1.0x102 cfu/ml, Okonko et al, (2008)

Fig. 3: Comparisons of Trends of TDS, Conductivity and pH Along The Constructed Wetland

0

100

200

300

400

500

600

700

0 20 40 60 80 100 120 140 160

Distance From Influent Along The Series of Wetland

Valu

es o

f Phy

sica

l Pro

perti

es

Total Dissolved Solids, TDS, (ppm) Conductivity (Millilitres/sec) pH

Fig. 7: Variation of Nitrate and Ntrogen Concentrations Within The Wetland Series

0

0.5

1

1.5

2

2.5

3

3.5

4

0 20 40 60 80 100 120 140

Distance From Influent Along The Wetland Series

Con

cent

ratio

n (M

G/L

)

Nitrogen Concentration (MG/L) Nitrate Concentration (MG/L)

limit for water. FAO, (!997) recommended standard for water is nil. An interesting result of these tests is the presentation within the first chamber where inadequate reduction rate was observed from the records. This was corroborated by the photograph in Fig. 6 which shows that the water hyacinth in the first cell of the first Chamber, CA was weedy. Again the quality of the water hyacinth in the first chamber is generally lower than in the other chambers. Annexed photo is for CB. Results from locations G, H and I, indicate that they are not polluted by the wetlands. However, the colony-forming units/ml, (cfu/ml) result for station H, 300m upstream of discharge point, indicated higher pollution levels. Generally, from the records and trends presented, it can be said that the constructed wetland series has been able to remove contaminants from the wastewater adequately. The concentrations of Nitrogen and Nitrates in the samples range from 0.845mg/l to 0.258mg/l and from 3.718mg/l to 1.135mg/l respectively. Lowest values were recorded for Chamber CA exit point while highest values were for the fourth chamber in both cases. Though the concentration of Nitrate increased within the wetland series, its values were far below the 50mg/l limit which WHO guidelines recommended, Fawell, 2007. The concern for both nitrate and nitrite is the potential for methaemoglobin formation in bottle-fed infants. WHO guidelines is based on epidemiological evidence which indicates that methaemoglobinaemia is rarely found in water concentration below 50mg/l. 6.0 CONCLUSIONS AND RECOMMENDATIONS A gradual reduction of 8% was achieved in the Total dissolved solids while 11% reduction was obtained in the conductivity within this constructed wetland series. The pH remained constant at 6.8 over the entire sampled area and its value though fell within acceptable range of 6.5 to 9. These imply that some level of treatment actually took place. The microbiological test results indicate a 99% reduction in the Most Probable Number of coliforms from 1600cfu/100ml in the wetland. A 100% reduction in this contaminant would have been achieved if the water hyacinth plant in the first cell of the first wetland chamber had been maintained without weed (Fig. 6 and its annex). The constructed wetland was able to record 85% reduction for coliform, 79% for staphylococcus, 52% for salmonella, 79% for salmonella and shigella, 66% for total viable count and 83% for fungi. Results of the colony units/ml, cfu/ml, for these parameters, obtained upstream, at point H and downstream, point I of the point of discharge into the canal compared with figures for point G showed adequacy of removal of contaminants by the constructed wetland series. Further work is being suggested on modeling of these interesting trends. Since the level of pollution at points H and I, which are expected to be the same, are not so, we are recommending that further work can be carried out to determine the rate of recovery of the water in the canal from pollution. Although the values of Nitrate levels within the wetland are far below the 50mg/l limit recommended by the WHO guidelines and do not pose any danger to pollution, the trend is believed to be reducing rather than rising. Further studies are required in this regard.

REFERENCES American Public Health Association. 1998. Standard Methods for the Examination of Water and Wastewater, 20th ed. APHA, Washington, DC. FAO, (Food and Agriculture Organisation), 1977. Chemical analysis manual for food and water, 5th Edition. FAO Rome 1: 20-26 Fawell, John, 2007. Drinking Water Standards and Guidelines. Foundation for Water Research, Allen House, The Listons, Liston Road, Marlow, Bucks SL 7 1FD, UK. February, 2007. Feng, P., Weagant, S. D. and M. A. Grant, 2002. Enumeration of Escherichia coli and the Coliform Bacteria. Bacteriological Analytical Manual Online, Sept, 2002 Hammer, M. J., 1977. Water and Waste-Water Technology SI version. John Wiley & Sons, Inc.: New York. Isiorho, S. A. 2006. The Challenge of maintaining urban wetlands. Presented August 30, 2006 at the International Symposium Wetlands 2006 Grand traverse resort near Traverse City, Michigan. MoDNR, (Missouri Department of Natural Resources), 2008. Water Quality Parameters, Quick Reference Guide. Field Services Division revised May 29 2008. P.O. Box 176, Jefferson City, MO 65102 800-361-4827 / 573-526-3315. E-mail: envirolab@dnr.mo.gov Oginni, F. A.. 2008. Rehabilitation of the Imhoff tank of a sewage treatment plant and implications for process line energy saving: Case study. Proceedings of the 1st National Engineering Technology Conference (NETeC 2008), 1st – 4th April, 2008, Ahmadu Bello University, Zaria, Nigeria. pp 68-77. Okonko, I. O., Adejoye, O. D., Ogunnusi, T. A., Fajobi, E. A. and O. B. Shittu. 2008. Microbiological and physicochemical analysis of different water samples used for domestic purposes in Abeokuta and Ojota, Lagos State, Nigeria. African Journal of Biotechnology Vol. 7 (5), pp. 617, 4 march, 2008. http://www.academicjournals.org/AJB ISSN 1684–5315 © 2008 Academic Journals. WHO, (World Health Organisation), 2000. WHO guidelines for drinking water quality training pack. Rome: WHO ACKNOWLEDGEMENT We appreciate the supports given by Indiana University-Purdue University Fort Wayne (IPFW), Ft. Wayne, Indiana USA and Covenant University, Ota, Ogun State, Nigeria. We thank Messrs. Segun Ishola, Ayo Falomo and Engr. Omole for helping in the sampling and data gathering and Engineers Noah, Albert and Paul for helping in providing information. Thanks to Folusho Oginni and Dr. Adekalu for editing of the paper.