The objective of the study was to evaluate the phytoremediation potential of the aquatic macrophyte Typha latifolia for removal of cadmium, chromium and lead from synthetic wastewaters in constructed
wetlands (CW). Four laboratory scale CW units were set up, each containing granite and soil. Typha latifolia was planted in the 1st unit then intercropped with Vetiveria zizanioides, Phragmites australis and
Cyperus latifolius in the 2nd, 3rd and 4th unit respectively. The units were treated to wastewaters of different metal concentrations and metal combinations. Wastewater was sampled at different retention periods. Results showed substantial reduction in metal concentrations. Metals were removed in the order Cr>Cd>Pb with maximum removal efficiencies being 96.36±0.52%, 95.70±1.26% and 80.59±3.58% for Cd, Cr and Pb respectively in the typha only units. The percentage removal of the metals increased with increase in retention time. This study recommends application of Typha latifolia in treatment of industrial and mine wastewater

Adedayo Adekunle Badejo (7226843)

Catherine Rwamba Githuku (7226834)

Julius Musyoka Ndambuki (7226837)

Ramadhan Wanjala Salim (7226840)

English

Loughborough University Institutional Repository

GITHUKU et al.  1  41st WEDC International Conference, Egerton University, Nakuru, Kenya, 2018   TRANSFORMATION TOWARDS SUSTAINABLE  AND RESILIENT WASH SERVICES    Treatment  potential  of  Typha  latifolia  in  removal  of  heavy  metals  from  wastewater  using  constructed  wetlands   C. R. Githuku (Kenya), J. M. Ndambuki, R. W. Salim & A. A. Badejo   PAPER 3036   The objective of the study was to evaluate the phytoremediation potential of the aquatic macrophyte Typha latifolia for removal of cadmium, chromium and lead from synthetic wastewaters in constructed wetlands (CW). Four laboratory scale CW units were set up, each containing granite and soil. Typha latifolia was planted in the 1st unit then intercropped with Vetiveria zizanioides, Phragmites australis and Cyperus latifolius in the 2nd, 3rd and 4th unit respectively. The units were treated to wastewaters of different metal concentrations and metal combinations. Wastewater was sampled at different retention periods. Results showed substantial reduction in metal concentrations. Metals were removed in the order Cr>Cd>Pb with maximum removal efficiencies being 96.36±0.52%, 95.70±1.26% and 80.59±3.58% for Cd, Cr and Pb respectively in the typha only units. The percentage removal of the metals increased with increase in retention time. This study recommends application of Typha latifolia in treatment of industrial and mine wastewaters.   Introduction  Environment may become contaminated with heavy metals as a result of natural occurrences as well as through emissions from rapidly expanding industrial and mining and mineral processing activities which release wastewaters that have high concentrations of toxic heavy metals (Sahu, 2014). Once in the environment, these metals are difficult and expensive to remove (Ali et al., 2013). Heavy metals are non biodegradable and therefore persist in the environment for a long time, causing irreversible damage to the environment (Iyengar, 2015). Owing to their toxic nature even at low concentrations (USEPA, 1996), heavy metals are known to cause enormous and irreversible damage to human beings and other living organisms by inducing cancer and damaging body organs (Abas et al., 2013; Iyengar, 2015). Cadmium (Cd), chromium (Cr) and lead (Pb) are heavy metals that are ranked among priority pollutants considered to be of great public health significance and concern (USEPA, 1996). Heavy metals need to be removed from wastewater prior to its disposal into receiving bodies (Abas et al., 2013). Removal technologies that have been in use, based on conventional treatment methods, are expensive and unfriendly to the environment (Odinga et al., 2013). Effective, environmentally friendly and affordable technologies are required in solving the problem of pollution of the environment with heavy metals. Constructed wetland technology has been acknowledged as an affordable and environmentally friendly technology (Sahu, 2014). However, despite its being cost effective and environmentally friendly, field application of constructed wetland technology has only been reported in developed continents such as America, Europe and Asia (Ranieri & Young, 2012). In most developing countries, these are yet to become available probably due to inadequate awareness. In a constructed wetland, plants are known to absorb and accumulate metals in their organs, thereby reducing the concentration of the metals in the wastewater (Abdelhakeem et al., 2016). The plants can be harvested after some growth period and either incinerated or composted to recycle the waste. If the harvested plants are incinerated, the ash produced whose volume is much less than the plant volume is disposed off in a harzardaous waste landfill. This study aimed at assessing the performance of constructed wetlands planted with Typha latifolia in treating synthetic wastewaters contaminated with Cd, Cr and Pb.  GITHUKU et al.  2  Methods  This study explored the potential use of Typha latifolia in removal of Cd, Cr and Pb from synthetic wastewater. An experiment was set up within Daspoort wastewater treatment plant in Pretoria West (25°44′S, 28°10′E), South Africa, consisting of lab scale wetland units planted with Typha latifolia as well as a combination of typha latifolia with Vetiveria zizanioides, Phragmites australis and Cyperus latifolius. The constructed wetland experiments consisted of 0.56 m diameter plastic containers that contained a 0.4 m deep layer of granite at the bottom and a 0.1 m layer of soil mixed with manure on top of the granite for plant growth (Figures 1 and 2). Synthetic wastewaters containing heavy metals were prepared by mixing measured quantities of metal salts cadmium nitrate, potassium dichromate and lead nitrate with tap water according to the parameters under study. The solutions were prepared with metal concentrations ranging between 1 and 5 mg/l for single-metal (Cd, Cr and Pb) and multi-metal (Cd+Cr, Cd+Pb, Cr+Pb and Cd+Cr+Pb) wastewaters and between 4 and 21 mg/l for wastewaters of varying initial metal concentrations (5, 10, 15 and 20 mg/l). The pH of the solutions was adjusted using HNO3 and NaOH. The units were operated in batch flow mode in which each unit received 50 litres of synthetic wastewater which was introduced into each unit from the top and allowed to percolate downwards. Sampling of single- and multi-metal wastewaters was done at 0, 3, 6 and 9 days while wastewaters of varying initial metal concentration was sampled at 0, 0.25, 1, 3, 6, 9, 15, 20 and 24 days after application of the metal solutions. The sampled waters were analysed for Cd, Cr and Pb using inductively coupled plasma (ICP), the concentrations of which were used in the calculation of metal removal efficiencies for the different wastewaters. Height measurements of the tallest typha plants was also done on days 0, 14, 30, 40, 60, 66, 67, 68, 70, 72, 75, 79, 88, 96, 107, 131 and 138.        Figure  1.  Plan  layout  of  the  experiment      Figure  2.  Vertical  view  of  a  wetland  unit   All statistical analyses were conducted using Statistical Package for Social Science (SPSS). Statistical analysis was carried out by one way ANOVA using student’s t-test to test significance of the difference between mean values.   Results  and  discussions   Application  of  single-­metal  wastewater   Effect of metals on plant’s growth The maximum heights reached by typha in the different metal solutions in a period of 150 days of growth, with wastewater being applied at day 60, are shown in Figure 3. Results show that the heights of typha in the different wastewaters increased with time within the experimental period, with a rapid increase at the beginning after application of the metal solutions followed by growth rate reduction. The rapid growth in Cd and Pb wastewaters could be attributed to the nitrates present in the salts that were used to prepare Cd and Pb solutions. In the case of Cr, rapid growth could be as a result of introduction of potassium since Cr solution was prepared from potassium dichromate. This agrees with Suhendrayatna et al. (2009) who reported that Cr, Pb and Cd were found to improve growth of vegetables. Typha was able to grow well in environments contaminated with heavy metals Cd, Cr and Pb. The growth was however observed to be least in the Cd media with the height in Cd media being lower than the heights in the Cr and Pb media. This implied that, compared with Cr and Pb, Cd had some retarding effect on growth of typha, possibly attributed to the inhibition of mitotic index (tissue growth) as noticed by Vecchia TyphaTypha+ VetiverTypha+PhragmitesTypha+CyperusSoil+Manure 10 cmGranite 40 cmWastewater InflowEffluentGITHUKU et al.  3  et al., (2005) in Cd metal treatment. A reduction in growth of other plants as a result of Cd is also supported by other researchers such as Mandakini et al., (2016) and Zhang et al. (2014).      Figure  3.  Maximum  heights  attained  in  different  wastewaters      Effect of contact time and plant combinations The removal efficiencies when typha was grown on its own and when grown in combination with another 3 plant species (vetiver, phragmites and cyperus) are shown in Figures 4 (a), (b), (c) and (d) respectively.         Figure  4(a).  Typha      Figure  4(b).  Typha+vetiver        Figure  4(c).  Typha+phragmites      Figure  4(d).  Typha+cyperus   Results indicate overall metal removals in the order of Cr > Cd > Pb, in all the plant combinations with Cr and Cd removals being significantly higher than Pb removals. Removal efficiency of all metals increased rapidly with increased time in the initial stage and then levelled off. The optimum time for the metal removal was observed to be 6 days regardless of the plant combinations. In this study, Cr maximum removal values ranged between 81.02 and 99.42% which are a lower than a value of 99.59%, obtained by Suhendrayatna et al., (2009) for typha but higher than 68.1% by Kumari & Tripathi. The maximum Cd removal values in this study ranged between 86.39 and 98.91%, values comparable to 94% by Yang et al. (2006) and 91% by Ye et al., (2001) but higher than 60% by Kumari & Tripathi. The Pb maximum removal values in this study ranged between 66.88 and 83.83%. This was lower than the Pb removal by Lan et al., (1992) and Lim et al. 0501001502000 25 50 75 100 125 150Plant Height (cm)Time (days)Cd Cr Pb0204060801001200 2 4 6 8 10Removal Efficiency (%)Retention time (days)Cd Cr Pb0204060801001200 2 4 6 8 10Removal Efficiency (%)Retention time (days)Cd Cr Pb0204060801001200 2 4 6 8 10Removal Efficiency (%)Retention time (days)Cd Cr Pb0204060801001200 2 4 6 8 10Removal Efficiency (%)Retention time (days)Cd Cr PbGITHUKU et al.  4  (2003) but higher than the Pb removal by Kumari & Tripathi (2015). This study showed that typha performed better on its own than when in combination with phragmites or cyperus, contrary to findings by Kumari & Tripathi (2015) and Marchand et al. (2010).  Effect  of  combining  metals  on  removal  efficiency  Tables 1, 2 and 3 show maximum removal efficiencies of Cd, Cr and Pb respectively in the wetland units.  Table  1.  Maximum  Cd  removal  efficiencies  Plant   Cd  only   Cd+Cr   Cd+Pb   Cd+Cr+Pb  %   Day   %   Day   %   Day   %   Day  Typha   97.19   6   94.90   6   96.33   9   97.02   6  Typha+Vetiver   98.91   6   96.18   3   96.41   9   96.52   9  Typha+Phragmites   89.12abc   3   96.45ad   6   94.83bd   9   95.61c   6  Typha+  Cyperus   86.39  abc   6   97.36a   6   95.96b   9   97.04c   9  Note:  Same  superscript  a,  b  and  c  in  one  row  indicates  significant  difference  at  p=0.05  level   Table  2.  Maximum  Cr  removal  efficiencies  Plant   Cr  only   Cd+Cr   Cr+Pb   Cd+Cr+Pb  %   Day   %   Day   %   Day   %   Day  Typha   99.37abc   6   94.07a   6   93.98b   9   95.36c   6  Typha+Vetiver   99.42abc   9   95.33ad   3   93.78bd   6   95.06c   6  Typha+Phragmites   96.61   9   95.25   3   94.74   6   93.70   6  Typha+  Cyperus   81.02abc   3   95.21a   6   89.72b   9   97.13c   9  Note:  Same  superscript  a,  b  and  c  in  one  row  indicates  significant  difference  at  p=0.05  level   Table  3.  Maximum  Pb  removal  efficiencies  Plant   Pb  only   Cd+Pb   Cr+Pb   Cd+Cr+Pb  %   Day   %   Day   %   Day   %   Day  Typha   83.83   9   73.97   6   89.12   6   75.43   6  Typha+Vetiver   77.66   3   80.16   6   79.61   6   78.61   6  Typha+Phragmites   79.02   9   82.25   6   79.78   6   73.27   9  Typha+  Cyperus   72.30   6   71.67   6   58.80   9   71.25   9   Overall, the percentage metal removal was observed to increase with the increase in retention time in all units. In single-metal wastewaters, the metal removal order was Cr > Cd > Pb, while in multi-metal wastewaters, the metal removal order was Cd ≈ Cr > Pb, with Cd and Cr removals being significantly higher than Pb removals in both cases.  Effect  of  initial  metal  concentration  on  removal  efficiency  Table 4 shows the maximum Cd, Cr and Pb percentage removals from varying initial metal concentration wastewaters. It was observed that removal efficiency increased with metal concentration from 5 to 20 mg/l, with Cd and Cr removal efficiencies from 5 mg/l wastewater being significantly lower than removal GITHUKU et al.  5  efficiencies from 20 mg/l wastewater. Pb removal efficiency from 5 mg/l wastewater was significantly lower than removal efficiencies from 15 and 20 mg/l wastewater. Removal of the 3 metals was in the order Cd > Cr > Pb.  Table  4.  Maximum  metal  removal  efficiencies  –  Varying  initial  metal  concentrations  Heavy  Metal   5  mg/l   10  mg/l   15  mg/l   20  mg/l  %   Day   %   Day   %   Day   %   Day  Cadmium   96.90a   15   98.52   9   98.95   24   99.24a   9  Chromium   89.29a   15   95.80   6   96.62   15   97.93a   9  Lead   61.41bc   15   80.58   6   85.21b   1   91.42c   3  Note:  Same  superscript  a,  b  and  c  in  one  row  indicates  significant  difference  at  p=0.05  level   Conclusions  and  recommendations  This study showed that Typha latifolia singly, as well as in combination with Vetiveria zizanioides, Phragmites australis and Cyperus latifolius, was able to effectively treat the single- and multi-metal wastewaters. Combining typha with phragmites and cyperus was found to enhance Cd and Cr removals but slightly retard Pb removal. Combining metals retarded Cd and Cr removal but had no defined effect on Pb removal. Removal efficiencies were found to increase with initial metal concentration from 5 to 20 mg/l. Metal removal from single- and multi-metal wastewaters was in the order Cr>Cd>Pb while in wastewater of varying concentration, the removal order was Cd>Cr>Pb. The removals were found to fall within the ranges reported by previous researchers. In all the units, removal efficiency was found to increase with time, reaching its maximum in 6 days in both single- and multi-metal wastewaters. This study shows that typha has a high capacity to reduce concentrations of Cd, Cr and Pb, and can indeed be used in treatment of metal polluted wastewaters, especially from mining and industrial activities.  Acknowledgements  The authors would like to thank the management of Daspoort Water Care Plant for allowing us to put up the constructed wetland units on their plant in Pretoria West and Tshwane University of Technology for funding the research work.  References  ABAS, S. N. A., ISMAIL, M. S. H., KAMAL, M. L. & IZHAR, S. 2013 Adsorption Process of Heavy Metals by Low-Cost Adsorbent: A Review. World Applied Sciences Journal, Vol. 28 (11), pp. 1518-1530. ABDELHAKEEM, S. G., ABOULROOS, S. A. & KAMEL, M. M. 2016 Performance of a vertical subsurface flow constructed wetland under different operational conditions. Journal of Advanced Research, 7, 803-814. ALI, H., KHAN, E. & SAJAD, M. A. 2013 Phytoremediation of heavy metals - Concepts and applications: Review. Chemosphere, Vol. 91, pp. 869-881. IYENGAR, B. K. 2015 Water Quality Concerns at Mines for Environmental Impact Assessment. International Journal of Innovative Research in Science, Engineering and Technology. Vol. 4(8), pp. 7973-7977. KUMARI, M. & TRIPATHI, B. D. 2015 Efficiency of Phragmites australis and Typha latifolia for heavy metal removal from wastewater. Ecotoxicology and Environmental Safety, Vol. 112, pp. 80-86.  LAN, C. Y., CHEN, G., LI, L. & WONG, M. H. 1992 Use of cattails in treating wastewater from a Pb/Zn mine. Environmental Management, Vol. 16, pp. 75-80. LIM, P. E., MAK, K. Y., MOHAMED, N. & NOOR A. M. 2003 Removal and speciation of heavy metals along the treatment path of wastewater in subsurface-flow constructed wetlands. Water Science & Technology. Vol. 48, No. 5 pp. 307-313. GITHUKU et al.  6  MANDAKINI, L. L. U., BANDARA, N. J. G. J. & GUNAWARDANA, D. 2016 A Study on the Phytoremediation Potential of Azolla pinnata under Laboratory Conditions. Journal of Tropical Forestry and Environment, Vol. 6. No 01 (2016), pp. 36-49. MARCHAND, L., MENCH, M., JACOB, D. L. & OTTE M. L. 2010 Metal and metalloid removal in constructed wetlands, with emphasis on the importance of plants and standardized measurements: A review. Environmental Pollution, Vol. 158, pp. 3447-3461. ODINGA, C. A., SWALAHA, F. M., OTIENO, F. A. O., RANJITH, K. R. & BUX, F. 2013 Investigating the efficiency of constructed wetlands in the removal of heavy metals and enteric pathogens from wastewater. Environmental Technology Reviews. 2013 Vol. 2, No. 1, pp. 1-16. RANIERI, E. & YOUNG, T. M. 2012 Clogging influence on metals migration and removal in sub-surface flow constructed wetlands. Journal of Contaminant Hydrology, Vol. 129-130, pp. 38–45. SAHU, O. 2014 Reduction of Heavy Metals from Wastewater by Wetlands. International Letters of Natural Sciences, Vol. 12, pp. 35-43. SciPress Ltd, Switzerland.  SUHENDRAYATNA, ZAKI, M., IRHAMNI & ELVITRIAN A. 2009 Chromium Ion Removal by Aquatic Plant, Typha latifolia cultivated from the Tsunami Affected Area (Preparation for application of heavy metal phytoremediation). 4th Annual International Workshop & Expo on Sumatra Tsunami Disaster & Recovery 2009. USEPA, 1996 Report: Recent Developments for Insitu Treatment of Metals Contaminated Soils, U.S. Environmental Protection Agency, Office of Solid Waste and Emergency Response. VECCHIA, F. D., LAROCCA, N., MORO, L., DEFAVERI, S., ANDREOLI, C. & RASCIO, N. 2005 Morphogenetic, ultrastructural and physiological damages suffered by submerged leaves of Elodea Canadensis exposed to cadmium. Plant Science, Vol. 168(2), pp. 329-338. YANG, B., LAN, C. Y., YANG, C. S., LIAO, W. B., CHANG, H. & SHU, W. S. 2006 Long-term efficiency and stability of wetlands for treating wastewater of a lead/zinc mine and the concurrent ecosystem development. Environmental Pollution, Vol. 143, pp. 499-512. YE, Z. H., WHITING, S. N., QIAN, J. H., LYTLE, C. M., LIN, Z-Q. & TERRY, N. 2001 Trace Element Removal from Coal Ash Leachate by a 10-Year-Old Constructed Wetland. American Society of Agronomy, Crop Science Society of America, Soil Science Society. Published in Journal of Environmental Quality, Vol. 30, pp. 1710-1719. ZHANG, X., XIA, H. & GAO, B. 2014 Effect of cadmium on growth, photosynthesis, mineral nutrition and metal accumulation on bana grass and vetiver grass. Ecotoxicology and Environmental Safety, Vol. 106, pp. 102-108.  Contact  details  Ms Catherine Githuku is a lecturer at Kenyatta University, Kenya with particular interests in environmental engineering and management and currently pursuing her doctorate at Tshwane University of Technology, SA. Prof. Julius Ndambuki and Prof Ramadhan Salim are lecturers at Tshwane University of Technology, SA on a variety of topics. Dr. Adedayo Badejo is also a lecturer at Federal University of Agriculture, Ogun State, Nigeria with particular interest in wastewater treatment.   Catherine Rwamba Githuku Tshwane University of Technology, Pta, SA, Tel: +27 63 136 3909; +254 72 184 3717 Email: rwamba_kiura@yahoo.com  Ramadhan Wanjala Salim Tshwane University of Technology, Pta, SA Tel: +27 (012) 382 5212 Email: salimrw@tut.ac.za  Julius Musyoka Ndambuki Tshwane University of Technology, Pta, SA Tel: +27 (012) 382 5225 Email: ndambukijm@tut.ac.za  Adedayo Adekunle Badejo Federal University of Agr., Abeokuta, Nigeria Tel: +234 813 007 1711 Email: dayo_badejo@yahoo.com  

Treatment potential of Typha latifolia in removal of heavy metals from wastewater using constructed wetlands

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Treatment potential of Typha latifolia in removal of heavy metals from wastewater using constructed wetlands

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