Abstract

• This study aims to evaluate efficiency of saponin, a natural surfactant, in remediation the soils which are smeared by crude oil and it was conducted based on the soil properties of oil ring no. (52), Nyaungdon Twonship, Ayeyarwaddy Region in 2019. For this purpose, soil properties were initially studied in this zone including soil texture, pH, moisture, nitrogen content, phosphorus content and potassium content. Crude saponin was extracted from the vegetable waste materials such as Onion (Allium cepa L.) skin, Ka Nyut (Asparagus officinalis L.) hard stem and Hin Nu Nwe (Amaranthus paniculatus L.) hard stem by the yield percent of 14.55 %, 2.53 % and 2.12 %, respectively. The studied phases included variables of saponin concentration within ranges of 250, 500 and 1000 ppm, contact time (10 week) and concentration of oil within ranges of 0.1-10 % in soil. The findings from assessment showed that the conditions under concentration of saponin (1000 ppm) on 0.1 % oil contaminated soil. The removal efficiency percentage of crude oil on 10 weeks contact time was observed 24.89 %. A laboratory study was extended to assess the potentials of local grass (Bermuda grass) under normal environmental conditions with or without surfactants in remediating soil contaminated with crude oil. The results of the phytoremediation of contaminated soil showed that significant reduction 76.3 % of crude oil was observed by natural saponin. It was also observed that the crude oil in the polluted soil was reduced by 72.4 % as a result of plant only, similar to commercial surfactant (SLES) treatment 72.1 %. This research indicates the soil remediation by Onion skin saponin, making better use of Bermuda grass and contributing to environmental protection.