TECHNICAL NOTE

 

Design and construction of laboratory-scale activated carbon, gravel and rice husk filter columns for the treatment of stormwater runoff from automobile workshops

 

 

C O Ataguba; I Brink

Correspondence

 

 

---

ABSTRACT

The design and construction of low-cost laboratory-scale filter columns using locally available Nigerian filter materials - granular activated carbon (GAC), gravel (GR) and rice husk (RH) - were carried out and reported. The filter materials and columns were designed, constructed and used for the treatment of stormwater runoff from selected automobile workshops in Nigeria over a period of three rainy months. The combined granular activated carbon and rice husk filter systems performed best with pollutant removal efficiency of 58%. It was shown that the materials, considered as waste, could be recycled and used as filter materials in the treatment of stormwater from automobile workshops. This low-cost technology for stormwater runoff treatment, especially for automobile workshops at large scale and in-situ, can be further explored.

Keywords: automobile workshop, filter media, pollution, stormwater runoff, treatment

---

 

 

INTRODUCTION

Stormwater runoff from automobile workshops washes debris, waste, oil combinations, grease, etc, through the drainage infrastructure within the urban catchment and discharges into receiving water bodies. This has resulted in a high degree of water pollution in Nigeria (Idu 2015; Ekiye & Zejiao 2010).

Studies have shown that land use plays a critical role in the concentration and composition of pollutants that are discharged into receiving water bodies (Khatun et al 2014; Shrestha 2017; Wang et al 2013). In a study carried out by Pitt et al (1995), it was reported that stormwater runoff from vehicle service and parking lots was found to have the highest levels of metals, petroleum hydrocarbon compounds and organics pollutants when compared with other urban land uses.

Conventional wastewater/stormwater treatment methods, such as reverse osmosis, chemical precipitation, electrodialysis, ion exchange, ultrafiltration, etc, have been reported to be unsuitable for adoption in developing countries due to high operating costs, high energy requirement and non-availability of appropriate labour to operate the technologies (Bahgat et al 1999). These challenges have created opportunities for the exploration of locally available materials/technologies.

In this research, the potential of combined (a) gravel - activated carbon, (b) activated carbon - rice husk, and (c) single rice husk as filter materials in the treatment of selected automobile workshop stormwater runoff was investigated. These materials are readily available and affordable in Nigeria. Five automobile workshops were selected from the two study towns of Idah and Lokoja in Nigeria for this stormwater sampling and treatment. These selected workshops were named Automobile Workshops 1-5.

This technical note reports the design, construction and preliminary use of the combined (a) gravel - granular activated carbon, (b) granular activated carbon - rice husk, and (c) single rice husk filter materials as vertical columns for the treatment of automobile workshop stormwater runoff. Results of the laboratory investigation of the pre-treatment and post-treatment quality of the stormwater samples collected over the period of nine weeks of a rainy season in Nigeria have also been reported.

The use of these filter materials in water treatment is not a novel concept, as their uses, as documented by Halli et al (2018), Maebh (2016) and Lakhote et al (2016), have proved that they are good low-cost water treatment materials. These filter materials are ecologically safe, and need little or no regeneration due to their local availability and low production costs (Cecen & Aktas 2011; Baker et al 1992; Andersen 2016; Sukia 2020; Nurul Amin et al 2006; Zunaira & Zhi, 2017; Xu et al 2013; Chukwudebelu et al 2015).

 

MATERIALS AND METHODOLOGY

Figures 1(a - c) show the different filter materials adopted for this research. Similarly, Figure 2 is a schematic representation of the different filter media setups for the filtration process. These configurations/ order of arrangement of the filter columns in Figure 2 were basically the choice of the researchers. The denser filter materials were placed above the less dense ones. However, further research work may consider changing the configurations of the filter columns in order to study the quality of the effluents for comparison with these results.

 

 

The smooth surface gravel was obtained at minimal cost from the gravel mining site at the bank of the River Niger in Idah, Nigeria. Raw carbon was obtained from local dealers of carbon. The raw carbon was converted to granular activated carbon using thermal activation (pyrolysis) as described in McDougall (1991). Rice husk used for this research was obtained from the rice mill in Idah, Nigeria. Commercially available 100 mm diameter polyvinyl chloride (PVC) pipes were sourced from the local market and used to fabricate the filter columns. Other materials that were obtained and used for the construction of the filter columns were PVC filter mesh, Araldyte (sealant), flow regulator and discharge hose. The arrangements of these materials is schematically shown in Figure 3 Filter column stands were also fabricated to hold the individual columns as shown in Figures 2, 3 and 5.

 

 

 

 

 

 

Design and construction of granular activated carbon, gravel and rice husk filter columns

The vertical downflow bed filter system has been adopted from Wegelin (1996). This design concept is based on its ease of use of gravity flow in underdeveloped areas (Diaper 1965; Pratap et al 2007).

The details of the design equations, data and the relevant references used in the design of the filters are presented in Table 1 with the design equations from the references, while the dimensions are the authors' work. The design data in Table 1 was used to construct the columns and the setup for the entire filter systems as shown in Figures 3 and 4.

The PVC mesh was introduced in the setup as shown in Figure 3 to retain and hold back particles from the stormwater runoff that might cause blockage of the flow regulator. The PVC caps covering the PVC mesh at the bottom of the columns were sealed to the column using a commonly available water tight sealant called Araldyte to eliminate leakages in the system.

Filter system setups, stormwater sampling, treatment and laboratory analyses

The different filter materials designed in Table 1 were placed in the different filter columns and fastened to the fabricated stand as shown in Figure 4(b).

Stormwater sampling from each automobile workshop spanning a period of nine weeks during the rainy season was carried out according to Lowe et al (2018). The influents and effluents from the different filter setups were analysed for quality before (raw stormwater) and after treatment with the filter media (filtered effluents). Replacement of filter material was chosen over regeneration for this study, as it is economical, and materials are locally available at little or no cost. The parameters analysed included: pH, conductivity, turbidity, oil and grease (O&G), dissolved oxygen (DO), total dissolved solids (TDS), total solids (TS), total suspended solids (TSS), cadmium (Cd), copper (Cu), lead (Pb) and iron (Fe). These parameters were selected based on the characteristic pollutants associated with this land use (Pitt et al 1995). The parameters were analysed in accordance with APHA (2017) at the Water Quality Control Laboratory at the National Geosciences Research Laboratories in Kaduna, Nigeria. The efficiency of pollutant removal of each filter system was computed, as presented in Tables 2, 3 and 4.

The pollutant removal efficiency T_eof a particular filter system with respect to any particular parameter is given as:

Where:

C_d= concentration of a particular parameter from its untreated sample

C_x= concentration of the same parameter from the filtered sample x

(for x = filter systems GAC-RH, GR-GAC or RH).

 

RESULTS AND BRIEF DISCUSSION

The fabrication of these filter columns shown in Figure 4 was done with ease as the materials (100 mm diameter PVC pipe, stand, flow regulator, flexible hose, etc) were sourced locally in the study areas. A unit of the treatment facility was made up of three filter columns (Figure 4(a)). A total of three units of treatment facilities were constructed for each of the five automobile workshops. The filter stands were constructed with steel rods as shown in Figure 4(b). The pollutant removal efficiencies of the different low-cost filter systems for Automobile Workshop 4 for a preliminary period of three weeks with respect to each parameter are presented in Tables 2, 3, and 4. It is suggested that spent rice husk and GAC can be used as source of heat energy for local industries after sun-drying, while the gravel can be used for concreting. The impact of the filters disposal on the environment will be reduced.

Tables 2, 3, and 4 show the computed average performance of these filter systems in the treatment of the stormwater runoff in terms of pollutant removal efficiency. Figure 5 shows that the combined GAC-RH filter system performed best with average T_e~ 58%. The RH filter system and the combined Gravel-GAC filter systems followed the combined GAC-RH filter system with average T_e~ 49% and average T_e~ 40% respectively.

 

CONCLUSION AND RECOMMENDATION

The results obtained from the use of this technology showed that the combined GAC and RH filter system performed best in the pollutant removal efficiency (58%).

The RH filter (49%) and the combined GR and GAC (40%) filter systems respectively followed in pollutant removal efficiency. This technology can be upscaled for use in other environments, with modifications in the available filter materials and the need for sustainable use of the technology. Other cheap locally available agricultural waste materials, such as sugarcane bagasse, groundnut/melon shells, maize cobs, etc, can be explored for use as filter materials. It is highly recommended that other low-cost technology for stormwater runoff treatment, especially for automobile workshops at large scale and in-situ, be explored, researched and prototypes rolled out.

 

REFERENCES

Andersen, J E H 2016. Hydraulic performance of advanced treatment media to improve quality of stormwaterfrom airports exposed to de-icing chemicals. MSc Dissertation. Trondheim, Norway: Norwegian University of Science and Technology.         [ Links ]

APHA (American Public Health Association) 2017. Standard Methods for the Examination of Water and Wastewater. 22nd ed. Washington, DC: APHA.         [ Links ]

Bahgat, M, Dewedar, M A & Zayed, A 1999. Sand-filters used for wastewater treatment: Buildup and distribution of microorganisms. Water Research, 33(8): 1949-1955.         [ Links ]

Baker, F S, Miller, C E, Repik, A J & Tolles, E D 1992. Activated carbon. In Kirk Othmer Encyclopaedia of Chemical Technology, Wiley Online Library.         [ Links ]

Cecen, F & Aktas, Ö 2011. Activated Carbon for Water and Wastewater Treatment: Integration of Adsorption and Biological Treatment. New York: Wiley.         [ Links ]

Chukwudebelu, J A, Igwe, C C & Madukasi, E I 2015. Prospects of using whole rice husk for the production of dense and hollow bricks. African Journal of Environment, Science and Technology, 9(5): 493-501.         [ Links ]

Diaper, E W J 1965. Upflow and downflow filtration through graded media. Proceedings of the Institution of Civil Engineers, 30(2): 437.         [ Links ]

Ekiye, E & Zejiao, L 2010. Water quality monitoring in Nigeria. Case study of Nigeria's industrial cities. Journal of American Science, 6, 22-28.         [ Links ]

Idu, A J 2015. Threats to water resources development in Nigeria. Journal of Geology and Geophysics, 4: 205.         [ Links ]

Karthik, R G H, Abhishek, N P, Kishor, V R, Nikhil, E, Poornima, K B & Shivakumara, B 2018. Comparative analysis of locally available adsorbents for purification of water. International Research Journal of Engineering and Technology, 5(5): 1722-1726.         [ Links ]

Khatun, A, Bhattacharyya, K G & Sarma, H P 2014. Levels of pollutants in runoff water from different land uses in Guwahati City, Assam, India. Archives of Applied Science Research, 5: 96-100.         [ Links ]

Lakhote, A, Ahire, P, Dabholkar, P, Dhadambe, V & Gharat, S 2016. Comparative analysis of design of water filter for rural areas. International Journal of Innovative Research in Advanced Engineering, 3(12): 23-27.         [ Links ]

Lowe, J, de Leon, D, Collins, J, Hoover, R & Book, S 2018. Standard Operating Procedure for Collecting Grab Samples from Stormwater Discharges, Vol 1.1. Publication No 18-10-023. Olympia, WA: Washington State Department of Ecology. https://fortress.wa.gov/ecy/publications/summarypages/1810023.html.         [ Links ]

Maebh, A G 2016. Development of filtration technologies for effective, cost-efficient and robust water treatment. PhD Thesis. Galway, Ireland: National University of Ireland.         [ Links ]

McDougall, G J 1991. The physical nature and manufacture of activated carbon. Journal of the Southern African Institute of Mining and Metallurgy, 91(4): 109-120.         [ Links ]

Nurul-Amin, M D, Kaneco, S, Kitagawa, T et al 2006. Removal of arsenic in aqueous solutions by adsorption onto waste rice husk. Industrial and Engineering Chemistry Research, 45: 8105-8110.         [ Links ]

Pitt, R, Field, R, Lalor, M & Brown, M 1995. Urban stormwater toxic pollutants: Assessment, sources and treatability. Water Environment Research, 67(3): 260-275.         [ Links ]

Pratap, M R, Khambhammettu, U, Clark, S E & Pitt, R 2007. Stormwater polishing: Upflow vs downflow filters. Proceedings, World Environmental and Water Resources Congress, American Society of Civil Engineers, 15-19 May, Tampa, FL.         [ Links ]

Shrestha, D 2017. Characterization and modelling of stormwater for the City of Calgary. MSc Dissertation. Canada: University of Calgary.         [ Links ]

Sukia, S K 2020. Rice husk-derived adsorbents for water purification, Chapter 6. In Naushad, M & Lichtfouse, E (Eds.), Green Materials for Wastewater Treatment, Cham, Switzerland: Springer.         [ Links ]

USACE (United States Army Corps of Engineers) 2001. Adsorption Design Guide. Guide 1110-1-2. US Department of the Army.         [ Links ]

Wang, S, He, Q, Hainan, A, Wang, Z & Zhang, Q 2013. Pollutant concentrations and pollution loads in stormwater runoff from different land uses in Chongqing. Journal of Environmental Sciences, 25(3): 502-510.         [ Links ]

Wegelin, M 1996. Surface Water Treatment by Roughing Filters. A Design, Construction and Operation Manual. St. Gallen, Switzerland: SKAT Consulting Ltd.         [ Links ]

Xu, M, Liu, X, Tang, Q, Qu, R & Xu, Q 2013. Utilization of rice husks modified by organomultiphosphonic acids as low-cost biosorbents for enhanced adsorption of heavy metal ions. Bioresource Technology, 149: 420-424.         [ Links ]

Zunaira, A & Zhi, C 2017. Removal of arsenic from drinking water using rice husk. Applied Water Science, 7: 1449-1458.         [ Links ]

 

 

Correspondence:
Clement Oguche Ataguba
Department of Civil Engineering, Stellenbosch University
Private Bag X1, Matieland, Stellenbosch 7602, South Africa
T: +234 803 567 1452; E: clematrix2008@gmail.com

Isobel Brink
Department of Civil Engineering, Stellenbosch University
Private Bag X1, Matieland, Stellenbosch 7602, South Africa
T: +27 21 808 4195; E: icbrink@sun.ac.za

 

 

 

ENGINEER CLEMENT OGUCHE ATAGUBA is a lecturer at the Federal Polytechnic, Idah, in Nigeria, where he teaches civil and water resources engineering courses at both National and Higher National Diploma levels. His research interests are in water quality/treatment, municipal waste management, water sanitation and hygiene (WASH), and the application of computer technology in water resources and sanitation facilities management. He is currently a PhD student at Stellenbosch University.

 

 

DR ISOBEL BRINK is a senior lecturer in water quality and environmental engineering at the Department of Civil Engineering, Stellenbosch University. She is interested in new innovations in water quality improvement methods and undertakes projects with wide application. Recent research includes simple point-of-use systems for potable water treatment, river water quality modelling, and the use of green infrastructure and LID technologies for surface runoff water quality improvement.