Biodegradasi Hidrokarbon Tanah Tercemar Limbah Oli Bekas Dengan Biostimulasi Menggunakan Ekoenzim

Abstract

Soil contamination caused by used motor oil waste is a serious environmental problem because it contains hydrocarbon compounds classified as toxic and difficult to degrade naturally. This study aimed to determine the effect of ecoenzyme addition as a biostimulant on the reduction of Total Petroleum Hydrocarbon (TPH) levels and the growth of indigenous bacterial populations in soil contaminated with used motor oil waste. The study was conducted from August to November 2025 at the Microbiology Laboratory of UIN Sumatera Utara. Contaminated soil samples were taken from an automotive workshop area in the Setia Budi District, Medan Selayang. This experimental study used a Completely Randomized Design (CRD) with treatments consisting of control (K), P1 (0.5 kg soil + 0.5 L ecoenzyme), and P2 (0.6 kg soil + 0.4 L ecoenzyme), with three replications each. Observations were conducted over 35 days at intervals of days 0, 7, 14, 21, 28, and 35. Parameters measured included TPH levels, temperature, pH, moisture content, and bacterial colony counts. Results showed that ecoenzyme addition significantly reduced TPH levels: P1 decreased from 18% to 0.7%, P2 to 2.6%, and the control to 13.4%. Bacterial populations in P1 increased to 3.25 × 10⁶ CFU/mL, P2 reached 2.74 × 10⁶ CFU/mL, while the control only reached 9.81 × 10⁵ CFU/mL. Statistical analysis using One-Way ANOVA showed significant differences among treatments. Treatment P1 was the best condition for reducing TPH levels to below the quality standard (<1%). Ecoenzymes proved effective as biostimulation agents in enhancing microbial activity and accelerating hydrocarbon biodegradation.