EFFECTIVENESS OF HORIZONTAL ROUGHING FILTER COMBINED WITH SELECTED ALGAE SPECIES ON QUALITY OF GREYWATER AND PRODUCTION OF USEFUL BIOMASS

2022-03-01T14:45:12Z

EFFECTIVENESS OF HORIZONTAL ROUGHING FILTER COMBINED WITH SELECTED ALGAE SPECIES ON QUALITY OF GREYWATER AND PRODUCTION OF USEFUL BIOMASS ADEJUMO, MUMUNI Discharging greywater into open ground remains a major management practice usually causing surface water pollution and exposure of people to water-related diseases particularly in low to middle income communities. Studies have shown that treatment of greywater with Horizontal Roughing Filter (HRF), a primary treatment process for wastewater, combined with algae species (sp.) has not been adequately utilized in Nigeria. However, cultivating algae on HRF-treated greywater may reduce surface water pollution, water-related diseases and produce useful biomass than opting for open discharge. Therefore, this study evaluated the effectiveness of Chlorella sp. combined with HRF (CHRF) and Scenedesmus sp. combined with HRF (SHRF) in greywater treatment and production of useful biomass. Greywater was sourced from households in Kube-Atenda community, Ibadan North Local Government Area, and subjected to CHRF and SHRF treatments while untreated sample served as control. Cultures of the algae species (Chlorella sp. and Scenedesmus sp.) were isolated from a fish pond in Ibadan and identified by their morphological characteristics. Growth conditions of the Chlorella sp. and Scenedesmus sp. were optimised in the laboratory and an outdoor experiment was conducted in a fabricated 100L capacity batch type treatment unit. Greywater (75L) was used with Chlorella sp. and Scenedesmus sp. inoculation dose of 20% for 12 days (a batch) over a period of 3 months (6 batches) for each of CHRF and SHRF treatments. Samples from each of the treatments and control were analysed for pH, Biochemical Oxygen Demand (BOD), nitrate, phosphate and Total Coliform (TC) using standard methods. Algae samples were analysed for chlorophyll-a, growth rate, crude protein and dry weight. Laboratory analyses were replicated three times and greywater quality results were compared with National Environmental Standards and Regulations Enforcement Agency (NESREA) quality standard. Data were analysed using descriptive statistics, t-test and ANOVA at α0.05. The pH of treated greywater were 9.1±0.6 (CHRF), 8.8±0.5 (SHRF) and 6.6±0.5 (control). The BOD (mg/L) reduced significantly from 125.7±6.4 (control), to 43.4±2.2 (CHRF) and 42.5±2.1 (SHRF), corresponding to 65.5% (CHRF) and 66.3% (SHRF) reduction. Nitrate concentration (mg/L) of the control, 42.1±2.9 significantly reduced to 11.6±0.8 (CHRF) and 10.4±0.7 (SHRF). Nitrate values of CHRF and SHRF were within the recommended limits (10-15 mg/L). Phosphate concentration (mg/L) reduced significantly from 16.8±3.9 (control) to 4.3±2.3 (CHRF) and 3.4±2.1 (SHRF). The TC count (MPN/100mL) of the control (8.3±2.1)x103 significantly reduced to (9.0±0.14)x102 and (7.8±0.12)x102, respectively, for CHRF and SHRF treated sample. The TC values of CHRF and SHRF were within the recommended limits (<103 MPN/100mL). Chlorophyll-a value was 3.8±2.7 mg/L (Chlorella sp.) and 4.2±2.8 mg/L (Scenedesmus sp.) with growth rate of 2.37 g/day (chlorella sp.) and 1.83 g/day (Scenedesmus sp.) Protein content (%) of Scenedesmus sp. 14.6±1.8 was significantly higher compared to 12.7±1.4 for Chlorella sp. while dry weight was 612.9±93.1 g (Scenedesmus sp.) and 576.2±95.7 g (Chlorella sp.). The Horizontal Roughing Filter in combination with algae was effective in treating greywater, and Scenedesmus species produced biomass with higher protein content and dry weight. This technology could be used in treating greywater and cultivate beneficial algae at the household level where wastewater treatment facilities are lacking.

LEVELS OF HEAVY METALS IN TRAFFIC- RELATED PARTICULATE MATTER ALONG A MAJOR MOTORWAY IN NORTHEAST LOCAL GOVERNMENT OF IBADAN

2019-03-19T13:58:02Z

LEVELS OF HEAVY METALS IN TRAFFIC- RELATED PARTICULATE MATTER ALONG A MAJOR MOTORWAY IN NORTHEAST LOCAL GOVERNMENT OF IBADAN AKINOLA, OLUSEGUN IDOWU Traffic-related particulate matter contributes extensively to ambient air pollution especially in urban centres and has been reported to cause respiratory illnesses. Hence, populations found along major urban motorways are at higher risk of various health effects. Although information on traffic-related particulate matter is available in Nigeria, data on particle-bound heavy metals are insufficient. This study was therefore designed to determine levels of heavy metals in the air along IdiApe-Iwo road motorway in Ibadan North-East Local Government Area. Descriptive study design involving air sampling and particulate analysis for selected heavy metals was used. Five purposively selected sampling locations (SL) 150 metres apart namely: Abayomi Area (AA), Iyana Agbala (IA), Barracks Area (BA), Agbaakin Layout (AL) and Holiness Junction (HJ) were selected along Idi Ape – Iwo road motorway. At each SL, levels of particulate matter (PM10) at intervals of 10, 20 and 30 metres away from the motorway were measured using calibrated fine particulate matter sampler. Also, traffic density was estimated via manual counting. Measurements were done in the morning (7- 10.30 am) and afternoon (1- 4.30 pm) for 10weeks. Filter papers obtained from the sampler from SL were digested and analysed for Lead (Pb), Iron (Fe), Copper (Cu), Cadmium (Cd), Zinc (Zn), Chromium (Cr) and Nickel (Ni) using atomic absorption spectrophotometry according to standard methods. Concentrations of heavy metals were compared with WHO guideline limits. Data were analysed using descriptive statistics, ANOVA and Pearson correlation test at p <0.05. Daily PM10 level at each SL were AB (100.5 ± 36.3 µg/m3), IA (96.3 ± 42.1 µg/m3), BA (84.6 ± 41.7 µg/m3), AL (110.1 ± 48.4 µg/m3), and HJ (121.6 ± 59.8 µg/m3) was 4-6 times above the PM10 guideline limit of 20 µg/m3. The mean levels of heavy metals were Pb (161.1 ± 108.3 mg/m3), Fe (2.54 ± 1.09 mg/m3), Cu (0.91 ± 0.31 mg/m3), Cd (52.5 ± 30.7 mg/m3), Zn (0.52 ± 0.39 mg/m3), Cr (0.19 ± 0.03 mg/m3) were also found to be higher than the WHO limit for Pb (0.0005 mg/m3), Fe (0.01 mg/m3), Cu (0.01 mg/m3), Cd (0.000005 mg/m3), Zn (0.04 mg/m3) and Cr (0.005 mg/m3). The peak heavy metal concentrations of Cd (248.8 mg/m3), Fe (8.95 mg/m3) were obtained in the morning while Pb (998.6 mg/m3), Cu (0.060mg/m3), Zn (1.03 mg/m3) and Cr (0.42 mg/m3) reached a peak in the afternoon. The mean traffic density was 3644.5± 820.7/hour. Spatial variations in PM10 and heavy metal concentrations were found to reduce with distance further away from traffic by 23.5% and 18.7% respectively. Mean concentrations of the heavy metals were found to increase with a rise in traffic density at each SL. Inter-SL variations were significant for all heavy metals except Pb (F=2.1, p=0.09) and Cu (F=0.18, p= 0.95). A significant positive correlation (r=0.84) was recorded between PM10 and traffic density. Levels of heavy metals at all sampling locations along Idi-Ape-Iwo road motorway exceeded standard guideline limits for urban centres. Periodic air monitoring of motorways should be instituted and relevant bodies such as Ministry of Environment should formulate policies aimed at reducing traffic-related particulate matter concentrations on our motorways especially exhaust emissions. Keywords: Air pollution, Heavy metals, Traffic density Words count: 487

Environmental Health Sciences

EFFECTIVENESS OF HORIZONTAL ROUGHING FILTER COMBINED WITH SELECTED ALGAE SPECIES ON QUALITY OF GREYWATER AND PRODUCTION OF USEFUL BIOMASS

LEVELS OF HEAVY METALS IN TRAFFIC- RELATED PARTICULATE MATTER ALONG A MAJOR MOTORWAY IN NORTHEAST LOCAL GOVERNMENT OF IBADAN