Application of constructed wetlands to the treatment of leachates from a municipal solid waste landfill in Ibadan, Nigeria.Introduction Ibadan is highly populous and is the largest indigenous city south of the Sahara, in tropical Africa Tropical African rain forests are tropical moist forests of semi-deciduous varieties distributed across nine West African countries -- Benin, Ghana, Guinea Bissau, Guinea, Ivory Coast, Liberia, Nigeria, Sierra Leone and Togo. , with an estimated population of over three million (U.N. Centre for Human Settlement (Habitat)/U.N. Environment Programme, 1997). It is located near the forest grassland grassland see grazing (2), pasture. boundary of southern Nigeria at an elevation of 20 meters above sea level Meters Above Sea Level is a standard metric measurement of the elevation of a location in reference to mean sea level. Uses Meters above sea level is the standard measurement of the elevation or altitude of: the act of burning to ashes. residues worldwide (Charlotte, 1998; Waite, 1995). The placement and compaction of municipal wastes in landfills and the infiltration of surface water or rain result in the production of leachates of diverse composition, which migrate vertically and laterally into the environment (Campbell, 1993). At the study site, leachates are discharged into environmental media without treatment. This circumstance has resulted in loss of biodiversity, leukemia leukemia (l  kē`mēə), cancerous disorder of the blood-forming tissues (bone marrow, lymphatics, liver, spleen) characterized by excessive production of immature or mature and other cancers,
developmental anomalies, low birth weights, low farm productivity,
release of obnoxious gases into the environment, and contamination of
domestic water sources in communities (Vrijheid, 2000).
The study reported here used constructed wetlands to treat leachates with the objective of reducing oxygen demand and trace metals to levels recommended by the national regulatory bodies in Nigeria. Constructed wetlands are complex, integrated systems in which plants, animals, water and the environment interact to improve water quality through duplication of natural wetland processes. Constructed wetlands are generally classified as either subsurface or free water surface systems, and are designed to allow gravitational grav·i·ta·tion n. 1. Physics a. The natural phenomenon of attraction between physical objects with mass or energy. b. The act or process of moving under the influence of this attraction. 2. flow of wastewater through the system. They have been applied elsewhere in the treatment of domestic wastewater (Souza & Bernardez, 1995), sewage (May et al., 1990), high-strength agricultural and industrial effluents (Job, Biddlestone, & Gray, 1991), leachates, acid mine drainage Acid mine drainage (AMD), or acid rock drainage (ARD), refers to the outflow of acidic water from (usually) abandoned metal mines or coal mines. However, other areas where the earth has been disturbed (e.g. , and stormwater, among substances (Sartaj & Fernandes, 1998). This paper considers the efficiency and effectiveness of Ipomoea aquatica Ipomoea aquatica is a semi-aquatic tropical plant grown as a leaf vegetable. Its precise natural distribution is unknown due to extensive cultivation, with the species found throughout the tropical and subtropical regions of the world. (Forsk) for treatment of wastewater in constructed-wetland systems in Nigeria. Materials and Methods Description of the Landfill The study location is described by Aluko, Sridhar, & Oluwande (2003). The landfill under study was built in 1994 as a sanitary landfill sanitary landfill: see solid waste. with drainage pipes and was lined with clay and gravel, although in reality, it is being used as an open dump. The operational practices at the site do not follow standard, normal practices. Nevertheless, the site was predominantly a containment landfill that was upgraded and commissioned in 1998. Overall, state-owned landfill sites are not properly managed. The landfill covers about 6 hectares of land, with solid wastes having been deposited to an estimated depth of about 1.5 meters. It has been used for municipal solid waste “Municipal waste” redirects here. For other uses, see Municipal waste (disambiguation). Municipal solid waste (MSW) is a waste type that includes predominantly household waste (domestic waste) with sometimes the addition of commercial wastes collected by a disposal for over eight years and receives domestic, industrial, and institutional wastes from public and private waste management operators (Aluko, 2001). Approximately 18 drains at the downstream portion of the landfill collect leachate leach·ate n. A product or solution formed by leaching, especially a solution containing contaminants picked up through the leaching of soil. draining from the landfill into a central pond. From this central pond leachates are discharged into the Omi Stream. The Omi Stream is the dominant source of water for about 16 villages in the Ona Ara Local Government area. Villagers also depend on water from this stream to process palm oil, which is their major preoccupation, and for their domestic demands. Sampling and Analysis of Leachates and Effluents Integrated samples of leachates were collected from randomly selected leachate drains at the site in accordance with American Public Health Association The American Public Health Association (APHA) is Washington, D.C.-based professional organization for public health professionals in the United States. Founded in 1872 by Dr. Stephen Smith, APHA has more than 30,000 members worldwide. (APHA) Standard 1060A3 (APHA, 1998). The samples were collected in clean, labeled plastic bottles that had been rinsed three times with raw leachates before sample collection. Fifty-five liters of leachates were collected between 8:00 a.m. and 10:00 a.m. and were transported to the laboratory immediately for analysis and further study. Effluents from constructed wetlands were collected from the 10-mm-diameter holes of the effluent chamber through discharge-level tubes at the end of the detention time of eight hours. In cases where analyses could not be completed daily, samples were stored in the refrigerator at 4[degrees]C before analysis. Analysis followed standard methods except where otherwise stated (APHA, 1998). Suspended solids Suspended solids refers to small solid particles which remain in suspension in water as a colloid or due to the motion of the water. It is used as one indicator of water quality. and turbidity turbidity /tur·bid·i·ty/ (ter-bid´i-te) cloudiness; disturbance of solids (sediment) in a solution, so that it is not clear.tur´bid Turbidity The cloudiness or lack of transparency of a solution. were determined with a portable data-logging HACH HACH Housing Authority of the City of Houston (Texas) DR/2010 spectrophotometer spectrophotometer, instrument for measuring and comparing the intensities of common spectral lines in the spectra of two different sources of light. See photometry; spectroscope; spectrum. dialed to their respective stored programs. Color was determined with a Lovibond color comparator comparator Instrument for comparing something with a similar thing or with a standard measure, in particular to measure small displacements in mechanical devices. In astronomy, the blink comparator is used to examine photographic plates for signs of moving bodies. , and pH was determined by the glass-electrode method with a Jenway (United Kingdom) Model 3020 standard calibrated cal·i·brate tr.v. cal·i·brat·ed, cal·i·brat·ing, cal·i·brates 1. To check, adjust, or determine by comparison with a standard (the graduations of a quantitative measuring instrument): pH meter. Dissolved solids, temperature, and conductivity were determined in situ In place. When something is "in situ," it is in its original location. with Jenway HACH TDS meters. Description of the Constructed-Wetland System The constructed wetland was based on the model developed by Jones, Cooper, and Hobson (1989), and used the vertical subsurface-flow method with gravel as the filtration media. The reactor incorporates layers of 0.2 meters of coarse to medium-sized sand on top of supportive layers of 0.5 meters of fine and coarse gravel. The sand layers were planted with Ipomoea aquatica (Forsk), and leachates were introduced into the system through the inlet zone and allowed to flow through the constructed-wetland system by gravity. A fully grown wetland was developed within four weeks from two stems that were planted onto the system. Ipomoea aquatica (Forsk) is an aquatic plant with a hollow stem that propagates by horizontal runners. The major characteristic that makes it a good biological support media for microorganisms is its extensive root system and rapid growth rate in an aquatic environment. Leachates were applied intermittently to the surface through the inlet zone in discrete doses of 5 liters per minute for 10 minutes per day, and effluents were collected from the underdrain of the effluent chamber at the end of the detention time. The depth of the filtration media was 0.8 m, and the dimension of the reactor was 1.2 m long by 0.5 m wide. Results The characteristics of the leachates and the effluents from constructed-wetland treatment are given in tables 1 through 4. The leachates had an average temperature of 25[degrees]C and a pH of 8.35. The mean values for influent-leachate color, turbidity, and conductivity were 456.5 Hazen units (HUs), 132 nephelometric turbidity units (NTUs), and 4,515 microsiemens per centimeter ([micro]S>/cm), and the effluent values were 17.5 HUs, 6.0 NTUs, and 1,393.5 [micro]S>/cm. The mean influent in·flu·ent adj. Flowing in or into. n. 1. An inflow, especially a tributary. 2. Ecology A nondominant organism in a community that exerts an important modifying effect. and effluent values for suspended solids, BOD BOD: see sewerage. , and COD were 197.5 mg/L and 37.5 mg/L, 712 mg/L and 99.5 mg/L, and 3,365 mg/L and 560.5 mg/L. Influent and effluent values for alkalinity al·ka·lin·i·ty n. The alkali concentration or alkaline quality of a substance that contains alkali. alkalinity 1. the quality of being alkaline. 2. and chloride were 1,444 mg/L and 307 mg/L, and 1,034 mg/L and 356 mg/L, respectively. There were 97.8 percent and 76.5 percent reductions in the effluent concentrations of ammonia and phosphate (610.9 mg/L and 0.595 mg/L), and there were mean increments of 246 percent and 184 percent in effluent concentrations of nitrate and dissolved oxygen, respectively. The ratio of BOD to COD was 0.21 in the influent leachate. Generally, constructed wetlands using Ipomoea aquatica (Forsk) gave reductions ranging from 72.2 percent to 97.9 percent in concentrations of trace metals. The highest reduction was achieved in lead concentrations; the mean influent-leachate concentration of lead was 1.641 mg/L. The lowest reduction was achieved in zinc, for which the mean influent concentration was 1.27 mg/L. Further reductions were achieved when leachates were passed twice through the constructed-wetland system (Table 4). Typical among the parameters were suspended solids, BOD, and ammonia, whose values were reduced, respectively, from 38.7 mg/L. 163 mg/L, and 12 mg/L to 27.3 mg/L, 62.5 mg/L, and 5.3 mg/L. Discussion Health effects resulting from land degradation The causes of land degradation are mainly anthropogenic and agriculture related. The major causes include:
po·ta·ble adj. Fit to drink; drinkable. potable fit to drink. water for domestic uses, loss of biodiversity, indiscriminate disposal of solid wastes, mismanagement mis·man·age tr.v. mis·man·aged, mis·man·ag·ing, mis·man·ag·es To manage badly or carelessly. mis·man  age·ment n. of waste disposal
facilities, and pollution of water sources from domestic and industrial
discharges of wastes are major concerns in Nigeria today. In a
developing country like Nigeria, this circumstance either bars or slows
down realization of the desirable objective of sustainable development Sustainable development is a socio-ecological process characterized by the fulfilment of human needs while maintaining the quality of the natural environment indefinitely. The linkage between environment and development was globally recognized in 1980, when the International Union .
The physical, chemical, and biological qualities of leachates from the landfill at Aba-Eku (Aluko et al., 2003) confirm the observations of Tairu (1999) who reported poor yield of farm produce, contaminated contaminated, v 1. made radioactive by the addition of small quantities of radioactive material. 2. made contaminated by adding infective or radiographic materials. 3. an infective surface or object. water sources, death of domestic animals, and death and loss of economic biota biota /bi·o·ta/ (bi-o´tah) all the living organisms of a particular area; the combined flora and fauna of a region. bi·o·ta n. The flora and fauna of a region. in addition to pollution as major problems facing about 32 communities that depend on the Omi Stream for domestic demands. A high and increased sickness rate was also reported among the residents in those communities. Residents whose major occupation is farming are using water from this polluted stream to process palm oil. There exists the possibility that palm oil processed in this locality may be absorbing fat-soluble toxicants from the Omi Stream, a circumstance that may affect consumers of the product from far and near. Therefore, finding an appropriate, sustainable, and cost-effective method of treating the strongly polluting leachates emanating from the landfill will protect the nation from detrimental consequences, both immediate and indirect, that will otherwise result from the direct disposal of raw leachates into the environment near Aba-Eku. The study reported here found high concentrations of pollutants pollutants see environmental pollution. in leachates except in nitrate, sulfate sulfate, chemical compound containing the sulfate (SO4) radical. Sulfates are salts or esters of sulfuric acid, H2SO4, formed by replacing one or both of the hydrogens with a metal (e.g., sodium) or a radical (e.g., ammonium or ethyl). , and phosphates (Table 1, Table 2). There is no threat of thermal pollution thermal pollution: see water pollution. in the Omi Stream since an average temperature of 25[degrees]C is acceptable in leachates. The leachates were amber in appearance, basic, and had a high ammonia concentration. This profile is typical of leachates from aged wastes, and if chemical treatment is employed, these leachates require a high dosage of coagulant coagulant /co·ag·u·lant/ (ko-ag´u-lint) promoting or accelerating coagulation of blood; an agent that so acts. co·ag·u·lant n. to ensure complete coagulation coagulation (kōăg'y lā`shən), the collecting into a mass of minute particles of a solid dispersed throughout a liquid (a sol), usually followed by the precipitation or . The values for
color, turbidity, and alkalinity were high, and iron represented the
bulk of metals in leachates. The concentrations of most pollutants were
between 1.5 percent and 80 percent above the national regulatory limit,
with the exception of nitrate, sulfate, and phosphate. The
concentrations of nitrogen and phosphate reduce the possibility of
eutrophication eutrophication (ytrō'fĭkā`shən), aging of a lake by biological enrichment of its water. In a young lake the water is cold and clear, supporting little life. of the Omi Stream.
The dissolved oxygen of the leachates was low, at 1.90 mg/L. This circumstance may be responsible for the death of economically valuable fish species of the Omi Stream as reported by Tairu (1999). The level of dissolved oxygen cannot support economic biota. This situation may result in anaerobiosis anaerobiosis /an·aer·o·bi·o·sis/ (an?ah-ro?bi-o´sis) metabolic processes occurring in the absence of molecular oxygen. an·aer·o·bi·o·sis n. (i.e., proliferation of undesirable facultative and anaerobic anaerobic /an·aer·o·bic/ (an?ah-ro´bik) 1. lacking molecular oxygen. 2. growing, living, or occurring in the absence of molecular oxygen; pertaining to an anaerobe. microorganisms) downstream (Peavy, 1985; Brock & Madigan, 1988). The mean dissolved oxygen of effluents from constructed wetlands, however, registered at up to 5.4 mg/L. This level will neither encourage development of septic septic /sep·tic/ (sep´tik) pertaining to sepsis. sep·tic adj. 1. Of, relating to, having the nature of, or affected by sepsis. 2. conditions nor pose any problem to aquatic flora in the receiving media when this treatment method is eventually implemented onsite (Table 1). The study reported here found that a high degree of purification was achieved in effluents produced from constructed-wetland systems. The performance of the constructed wetlands was good, achieving 81.01 percent and 86.03 percent reductions in suspended solids and BOD, respectively, while reductions in COD. ammonia, and lead were 83.34 percent, 97.77 percent, and 97.93 percent, respectively. If employed onsite, this method of treatment will reverse the detrimental effects from discharge of raw leachates into the Omi Stream and its surrounding environment. There will be improvement in farm output, reduction in spontaneous deaths of domestic animals, and improvements in water sources over time, and the palm oil output from the neighboring communities will be safe for consumption. The efficiency and effectiveness of constructed wetlands using Ipomoea aquatica (Forsk) in treating leachates is attributed to the development of a microbial microbial pertaining to or emanating from a microbe. microbial digestion the breakdown of organic material, especially feedstuffs, by microbial organisms. film on the filtration media, its adaptation to feed leachate, and the diversity of the biofilm Biofilm An adhesive substance, the glycocalyx, and the bacterial community which it envelops at the interface of a liquid and a surface. When a liquid is in contact with an inert surface, any bacteria within the liquid are attracted to the surface and adhere , which mineralizes and degrades the components of leachates to satisfy biochemical and oxygen requirements (Horan, 1991; Brock and Madigan, 1988; Peavy, 1985). A constructed wetland is cost-effective and simple to operate, and it will produce effluent of consistent quality when mature. Minimal skills are required for effective performance (Jones, Cooper, & Hobson, 1989; Worrall, Peberdy, & McGinn, 1998). The results of the study reported here represent performance at the early stage of development of the system, before full establishment of vegetation on the constructed-wetland beds and full acclimatization acclimatization Any of numerous gradual, long-term responses of an individual organism to changes in its environment. The responses are more or less habitual and reversible should conditions revert to an earlier state. of leachates to the system. The efficiency of treatment could also be attributed to the tropical climate A tropical climate is a type of climate typical in the tropics. Köppen's widely-recognized scheme of climate classification defines it as a non-arid climate in which all twelve months have mean temperatures above 18°C (64.4 °F). in Nigeria, which usually supports optimum biological activity. The marginally high concentration of pollutants in effluents was due to the very high values of pollutants in the feed leachates. Most wetlands have been built to serve as secondary and tertiary treatment systems until they are mature, when they will be switched to treating screened wastewater. Cycling the effluents of constructed wetlands once more through the same system, however, produces a better-purified effluent that can be safely discharged into the environment (Table 4). Therefore building constructed wetlands in series will improve the efficacy of treatment at minimal cost. Phytroremediation holds great promise in developing countries such as Nigeria, where projects are hindered by limitations on finances. It is anticipated that performance will improve when the rhizophere fully ramifies through the filtration media, the microbial film fully develops on the gravel bed, and the constructed wetland system fully matures and adapts to the wastewater. Conclusions Constructed-wetland systems incorporating Ipomoca aquatica (Forsk) were found to be an economically viable way to restore environmental quality and to either eliminate or greatly reduce the diverse health, ecological, and environmental effects of contaminated domestic water sources associated with the disposal of raw leachates directly into the environment at Aba-Eku. This is of utmost importance in developing countries where projects are hindered or aborted a·bort v. a·bort·ed, a·bort·ing, a·borts v.intr. 1. To give birth prematurely or before term; miscarry. 2. To cease growth before full development or maturation. 3. mid-stream by limitations on finances. The study reported here provides useful information on the application of such systems and their feasibility for small-scale waste-water management at minimal cost in other geographical regions.
TABLE 1 Characteristics of Effluents from Constructed Wetlands Using
Ipomoea Aquatica (Forsk)*
Parameters (Unit) Influent
Temperature 102.87 [+ or -] 0.25
[degrees]F([degrees]C) (25.15 [+ or -] 0.25)
pH 8.35 [+ or -] 0.07
Color (HU) 456.5 [+ or -] 9.19
Turbidity (FTU) 132.0 [+ or -] 15.56
Conductivity ([micro]S/cm) 4,515.0 [+ or -] 148.49
Total Solids (mg/L) 6,062.5 [+ or -] 381.13
TSS (mg/L) 197.5 [+ or -] 21.92
TDS (mg/L) 5,865.0 [+ or -] 403.05
Alkalinity (mg/L) 1,444.0 [+ or -] 560.03
Chloride (mg/L) 1,034.0 [+ or -] 159.81
Sulphate (mg/L) 66.45 [+ or -] 13.95
Dissolved oxygen (DO) (mg/L) 1.895 [+ or -] 0.01
Biochemical oxygen demand 712.0 [+ or -] 62.23
(BOD) (mg/L)
Chemical oxygen demand 3,365.0 [+ or -] 31.11
(COD) (mg/L)
Parameters (Unit) Effluent
Temperature 103.77 [+ or -] 0.35
[degrees]F([degrees]C) (25.65 [+ or -] 0.35)
pH 7.5 [+ or -] 0.14
Color (HU) 17.5 [+ or -] 3.54
Turbidity (FTU) 6.0 [+ or -] 0.00
Conductivity ([micro]S/cm) 1,393.5 [+ or -] 217.08
Total Solids (mg/L) 899.0 [+ or -] 144.25
TSS (mg/L) 37.5 [+ or -] 6.36
TDS (mg/L) 861.5 [+ or -] 150.61
Alkalinity (mg/L) 307.0 [+ or -] 216.38
Chloride (mg/L) 356.0 [+ or -] 32.53
Sulphate (mg/L) 57.3 [+ or -] 20.08
Dissolved oxygen (DO) (mg/L) 5.4 [+ or -] 0.16
Biochemical oxygen demand 99.5 [+ or -] 5.66
(BOD) (mg/L)
Chemical oxygen demand 560.5 [+ or -] 84.15
(COD) (mg/L)
Percentage
Parameters (Unit) Removed (%) p-Value FEPA Standard**
Temperature -- -- <131 (<40)
[degrees]F([degrees]C)
pH -- -- 6-7
Color (HU) 96.17 .0004 7
Turbidity (FTU) 95.46 .005 --
Conductivity ([micro]S/cm) 69.15 .002 --
Total Solids (mg/L) 85.17 .002 --
TSS (mg/L) 81.01 .007 30
TDS (mg/L) 85.31 .003 2,000
Alkalinity (mg/L) 78.74 .116 --
Chloride (mg/L) 65.57 .024 600
Sulphate (mg/L) 13.77 .648 500
Dissolved oxygen (DO) (mg/L) 184.21*** .004 --
Biochemical oxygen demand 86.03 .012 50
(BOD) (mg/L)
Chemical oxygen demand (COD) 83.34 .002 --
(mg/L)
* Values are mean of 12 individual and separate samples obtained from
the same sampling point and treatment system for influent and effluent
samples, respectively.
** FEPA Standard = Nigeria Federal Environmental Protection Agency
standard for discharge into surface waters (1991).
*** Percentage increase.
TABLE 2 Nitrogen and Phosphate Quality of Effluents from Constructed
Wetlands Using Ipomoea Aquatica (Forsk)*
Parameter (Unit) Influent Effluent
Ammonia (mg/L) 610.9 [+ or -] 365.43 13.6 [+ or -] 3.82
Nitrate (mg/L) 1.06 [+ or -] 0.31 3.67 [+ or -] 0.23
Phosphate (mg/L) 0.595 [+ or -] 0.02 0.14 [+ or -] 0.06
Parameter (Unit) Percentage Removed (%) p-Value FEPA Standard**
Ammonia (mg/L) 97.77 0.148 --
Nitrate (mg/L) 246.23*** 0.008 20
Phosphate (mg/L) 76.47 0.008 5
* Values are mean of 12 individual and separate samples obtained from
the same sampling point and treatment system for influent and effluent
samples, respectively.
** FEPA Standard = Nigeria Federal Environmental Protection Agency
standard for discharge into surface waters (1991).
*** Percentage increase.
TABLE 3 Trace Metals Quality of Effluents from Constructed Wetlands
Using Ipomoea Aquatica (Forsk)*
Parameters (Unit) Influent Effluent
Lead (mg/L) 1.641 [+ or -] 1.88 0.034 [+ or -] 0.01
Nickel (mg/L 0.875 [+ or -] 0.08 0.161 [+ or -] 0.04
Cadmium (mg/L) 0.164 [+ or -] 0.07 0.032 [+ or -] 0.02
Iron (mg/L) 198.141 [+ or -] 129.36 3.608 [+ or -] 0.15
Manganese (mg/L) 23.222 [+ or -] 12.19 0.091 [+ or -] 0.11
Zinc (mg/L) 1.271 [+ or -] 0.08 0.353 [+ or -] 0.40
Parameters (Unit) Percentage Removed (%) p-value FEPA Standard**
Lead (mg/L) 97.93 0.121 <1
Nickel (mg/L 81.60 0.006 <1
Cadmium (mg/L) 80.49 0.011 <1
Iron (mg/L) 98.18 0.121 20
Manganese (mg/L) 99.61 0.121 5
Zinc (mg/L) 72.23 0.085 <1
* Values are mean of 12 individual and separate samples obtained from
the same sampling point and treatment system for influent and effluent
samples, respectively.
** FEPA Standard = Nigeria Federal Environmental Protection Agency
standard for discharge into surface waters (1991).
TABLE 4 Characteristics of Effluents After Cycling Twice on Constructed
Wetlands Using Ipomoea Aquatica (Forsk)*
Parameters (Unit) Influent Effluent
pH 7.6 [+ or -] 0.02 7.5 [+ or -] 0.01
Color (HU) 17.0 [+ or -] 0.01 11.0 [+ or -] 0.01
Turbidity (NTU) 7.0 [+ or -] 0.03 4.0 [+ or -] 0.00
SS (mg/L) 38.7 [+ or -] 0.14 27.3 [+ or -] 0.06
TDS (mg/L) 876.5 [+ or -] 0.61 812.8 [+ or -] 0.45
DO (mg/L) 4.8 [+ or -] 0.03 5.43 [+ or -] 0.16
BOD (mg/L) 163.0 [+ or -] 0.12 62.5 [+ or -] 0.10
Ammonia (mg/L) 12.0 [+ or -] 0.05 5.3 [+ or -] 0.03
Lead (mg/L) 0.04 [+ or -] 0.01 0.03 [+ or -] 0.01
Nickel (mg/L) 0.16 [+ or -] 0.01 0.09 [+ or -] 0.02
Zinc (mg/L) 0.29 [+ or -] 0.02 0.22 [+ or -] 0.01
Parameters (Unit) Percentage Removed (%) FEPA Standard**
pH -- 6-7
Color (HU) 35.29 7
Turbidity (NTU) 42.86 --
SS (mg/L) 29.46 30
TDS (mg/L) 7.27 2,000
DO (mg/L) 184.21*** --
BOD (mg/L) 61.66 50
Ammonia (mg/L) 55.83 --
Lead (mg/L) 25.00 <1
Nickel (mg/L) 43.75 <1
Zinc (mg/L) 24.14 <1
* Values are mean of 12 individual and separate samples obtained from
the same sampling point and treatment system for influent and effluent
samples, respectively.
** FEPA Standard = Nigeria Federal Environmental Protection Agency
standard for discharge into surface waters (1991).
*** Percentage increase.
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Job, G.D., Biddlestone, A.J., & Gray, K.R. (1991). Treatment of high strength agricultural and industrial effluents using Reed bed  This article or section needs copy editing for grammar, style, cohesion, tone and/or spelling.You can assist by [ editing it] now. systems. Transactions of the Institute of Chemical Engineering, 69(A3), 187-189. Jones, S., Cooper, P.F., & Hobson, J.A. (1989). Sewage treatment Sewage treatment Unit processes used to separate, modify, remove, and destroy objectionable, hazardous, and pathogenic substances carried by wastewater in solution or suspension in order to render the water fit and safe for intended uses. by reed bed systems: The present situation in the UK. Journal of the Institution of Water & Environmental Management 3(1) 60. May, E., Butler, J.E., Ford, M.G., Ashworth, R., Williams, J., & Baghat, M.M.M. (1990). Chemical and microbiological processes in gravelbed hydrophobic hydrophobic /hy·dro·pho·bic/ (-fo´bik) 1. pertaining to hydrophobia (rabies). 2. not readily absorbing water, or being adversely affected by water. 3. (GBH GBH (in Britain and South Africa) grievous bodily harm ) systems for sewage treatment. In P.F. Cooper and B.C. Findlater (Eds.), Constructed wetlands in water and water pollution control (pp. 34-40). Oxford: Pergamon Press. Nigeria Federal Environmental Protection Agency Environmental Protection Agency (EPA), independent agency of the U.S. government, with headquarters in Washington, D.C. It was established in 1970 to reduce and control air and water pollution, noise pollution, and radiation and to ensure the safe handling and . (1991). S1.8 National Environmental Protection (Effluent Limitation) Regulation and S1.9 National Environmental Protection (Pollution Abatement in Industries and Facilities Generating Wastes) (FGPL 211/911/12,000). Lagos, Nigeria: Author. Ogban, F.E. (2000). Industry and water pollution. Environmental News, 6(1), 18-24. Onibokun, A.G., Adedipe, N.O., & Sridhar, M.K.C. (2000). Affordable technology and strategies for waste management in Africa: Lessons from experience (Centre for African Settlement Studies and Development (CASSAD) Monograph No. 13). Ibadan, Oyo State Ọyọ State is an inland state in south-western Nigeria, with its capital at Ibadan. It is bounded in the north by Kwara State, in the east by Osun State, in the south by Ogun State and in the west partly by Ogun State and partly by the Republic of Benin. , Nigeria: Centre for African Settlement Studies and Development. Peavy, S.H., Rowe, D.R., & Tchobanoglous, G. (1985). Environmental engineering. New Delhi New Delhi (dĕl`ē), city (1991 pop. 294,149), capital of India and of Delhi state, N central India, on the right bank of the Yamuna River. , India: McGraw-Hill. Sartaj, M., & Fernandes, L. (1998) "Attenuation Loss of signal power in a transmission. Attenuation The reduction in level of a transmitted quantity as a function of a parameter, usually distance. It is applied mainly to acoustic or electromagnetic waves and is expressed as the ratio of power densities. of leachate contaminants in an engineered wetland." In Proceedings of the 9th International Symposium on Water-Rock Interaction, 30 March-3 April 1998 (pp. 1001-1004). Rotterdam, Netherlands: A.A. Balkema. Souza, L.E., & Bernardez, R.S. (1995). Domestic wastewater treatment for a small community using an UASB UASB Upflow Anaerobic Sludge Blanket followed by constructed wetland cells. International Association of Water Quality, Specialist Group on the Use of Macrophytes in Water Pollution Control Newsletter, 13, 9-10. Tairu, T.T. (1999). Aspects of environmental impact assessment of solid waste disposal sites in Ibadan. Unpublished master's dissertation, University of Ibadan, Ibadan, Nigeria. U.N. Centre for Human Settlement (Habitat)/U.N. Environment Programme. (1997). City experiences and international support (Vol. 2). Nairobi, Kenya: Majestic Printing Works Ltd. Vrijheid, M. (2000). Health effects of residence near hazardous waste Hazardous waste Any solid, liquid, or gaseous waste materials that, if improperly managed or disposed of, may pose substantial hazards to human health and the environment. Every industrial country in the world has had problems with managing hazardous wastes. landfill sites: A review of epidemiological literature. Environmental Health Perspectives, 8(Suppl. 1), 101-112. Waite, R. (1995). Household waste recycling. London: EARTSCAN Publications Limited. Worrall, P., Peberdy, K., & McGinn, H. (1998). Construction of preliminary performance of reed bed treatment systems at Castle Espie Wildfowl and Wetlands Trust The Wildfowl and Wetlands Trust is a wildfowl and wetland conservation charity in the United Kingdom. Its patron is Queen Elizabeth II. It was founded in 1946 by the ornithologist and artist Sir Peter Scott, initially as the Severn Wildfowl Trust. Centre, Northern Ireland Northern Ireland: see Ireland, Northern. Northern Ireland Part of the United Kingdom of Great Britain and Northern Ireland occupying the northeastern portion of the island of Ireland. Area: 5,461 sq mi (14,144 sq km). Population (2001): 1,685,267. . International Journal for Water and Environmental Management, 12(2), 86-91. Olufemi Oludare Aluko, M.P.H. M.K.C. Sridhar, M.Sc., Ph.D. Corresponding Author: Olufemi Oludare Aluko, Doctoral Student, Division of Environmental Health, Department of Epidemiology. Medical Statistics and Environmental Health, Faculty of Public Health. College of Medicine, University of Ibadan, Ibadan, Oyo State, Nigeria 234-02. E-mail: ooaluko@yahoo.com. |
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