Current Applied Science and Technology

Abstract

This research was aimed at recycling agricultural waste and treating synthetic automobile service station wastewater. Wastewater was synthesized to two levels of COD concentration: 702 mg/L (WW-A) and 7,054 mg/L (WW-B). In the treatment process, 100 mM sodium peroxydisulfate with MnO_x-loaded biochar (MnO_x-Biochar) was applied. The MnO_x-Biochar was produced by dipping corn cob biochar in 40 mM manganese sulfate followed by pyrolyzed at 600°C. The surface area, pore volume, pore size, and pH value at the zero-point charge of MnO_x-Biochar were 130 m²/g, 0.044 cm³/g, 1.02 nm, and 7.05, respectively. From the FTIR spectrogram, a peak assignable to Mn-O was observed. The results showed that the initial pH of the wastewater did not affect the treatment efficiency. The optimum MnO_x-Biochar dosage was 2 g/L. Equilibrium was reached within 120 min of reaction. During the first 15 min, the treatment rate constants (k) of the WW-A and WW-B treatment were 0.0647 min^-1 and 0.0349 min^-1, respectively. After 15 min, the k values of the WW-A and WW-B treatments were reduced to 0.0242 min^-1 and 0.0094 min^-1, respectively. The overall treatment efficiencies of the low COD wastewater (WW-A) and high COD wastewater (WW-B) were 97% and 78%, respectively. The treatment mechanisms involved both adsorption and oxidation. The adsorption efficiencies of the WW-A and WW-B treatments were 36% and 18%, respectively.

Keywords: biochar; corn cob; manganese oxide; oxidation; sodium peroxydisulfate

*Corresponding author: Tel.: (+66) 971929905 Fax: (+66) 23298428

E-mail: kcchompoonut@gmail.com

References

Office of Agricultural Economics, Ministry of Agriculture and Cooperatives, 2021. Situations of Important Agricultural Products and Trends in 2022. [online] Available at: https://www.oae.go.th/assets/portals/1/files/jounal/2565/trendstat2565-Final-Download.pdf. (in Thai)

Grace, M.A., Clifford, E. and Healy, M.G., 2016. The potential for the use of waste products from a variety of sectors in water treatment processes. Journal of Cleaner Production, 137, 788-802.

Department of Energy Business, Ministry of Energy, 2021. List of fuel traders. [online] Available at: https://www.doeb.go.th/info/info_operat_fuel.php. (in Thai)

Sarmadi, M., Zarei, A.A., Ghahrchi, M., Sepehrnia, B., Meshkinian, A., Moein, H., Nakhaei, S. and Bazrafshan, E., 2021. Carwash wastewater characteristics - a systematic review study. Desalination and Water Treatment, 225, 112-148.

Rai, R., Sharma, S., Gurung, D.B., Sitaula, B.K. and Shah, R.D.T., 2019. Assessing the impacts of vehicle wash wastewater on surface water quality through physio-chemical and benthic macroinvertebrates analyses. Water Science, 40, 39-49.