Justin, L.D and Covenant University, Theses (2021) TREATMENT EFFICIENCY EVALUATION OF THREE MACROPHYTES FOR DOMESTIC WASTEWATER USING PILOT CONSTRUCTED WETLAND SYSTEM. Masters thesis, Covenant University Ota..
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Abstract
The need to treat wastewater prior to disposal into the environment is of utmost importance. The use of constructed wetland systems (CWS) is becoming more popular due to their operational efficiency and cost-effective advantages over conventional treatment methods. However, the efficiency of CWS depends on the efficiency of their most vital component; aquatic macrophytes in reducing wastewater pollutants. Therefore, this study was aimed at investigating the treatment efficiency of water hyacinth (Eichhornia crassipes), water lettuce (Pistia stratiotes) and duckweed (Lemnar minor) using pilot CWS. It also examined the conformity of the treated effluents with National Environmental Standards and Regulations Enforcement Agency (NESREA) effluent discharge/reuse limits. All the 14 NESREA standard effluent discharge parameters were analysed. However, special attention was given to six (6) of the parameters; Total Suspended Solids (TSS), Total Phosphorus (TP), Total Nitrogen (TN), Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD) and E.coli) which were above the standard discharge limits. Four pilot CWS were built using 150L tanks for the three plants and a control reactor. Local substrates; sand and gravel were used to optimize the pilot CW reactors. Effluents samples were collected every 7 days for 3 weeks, while maintaining 80% plant population. The result of pollutant removal efficiencies showed that water hyacinth and lettuce attained optimum results at 14 days hydraulic retention time (HRT) with 99.30% and 99.35% COD and TP removal, respectively. Water hyacinth was better at reducing BOD, COD, EC, TDS, DO and TC with efficiency of 97.31, 85.04, 90.35, 89.66, 95.95 and 65.99%, respectively. Howbeit, lettuce was more efficient in removing TSS, TP and E.coli at 96.24%, 97.55% and 94.43%, respectively. While duckweed reduced more of E.coli; 94.43% and TN; 90.83%. Generally, the overall results proved that water hyacinth was more effiecient, but all the three macrophytes were efficient in domestic wastewater treatment. Also, the treated wastewater effluents passed NESREA limits, hence it is fit for discharge/or reuse purpose. This study is therefore a major contributor to SDG6 (clean water and sanitation).
| Item Type: | Thesis (Masters) |
|---|---|
| Uncontrolled Keywords: | Domestic wastewater, wastewater treatment, constructed wetlands, macrophytes, water hyacinth, water lettuce, duckweed, sustainable technology |
| Subjects: | T Technology > TA Engineering (General). Civil engineering (General) |
| Divisions: | Faculty of Engineering, Science and Mathematics > School of Civil Engineering and the Environment |
| Depositing User: | Mrs Patricia Nwokealisi |
| Date Deposited: | 13 Jan 2022 10:34 |
| Last Modified: | 13 Jan 2022 10:34 |
| URI: | http://eprints.covenantuniversity.edu.ng/id/eprint/15566 |
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