Use of a novel biopellet to treat total petroleum hydrocarbon contaminated groundwater

Abstract

Conventional pump-and-treat strategies for dealing with groundwater contamination are both energy- and time-consuming. Potential passive biological techniques are of interest to remedy the massive volume of total petroleum hydrocarbon (TPH)-contaminated groundwater worldwide. In this study, novel biopellets made of TPH-acclimated microbes, fermented fruit peel materials, and CaO2 recycled from eggshells were manufactured to treat TPH-contaminated groundwater. The biopellets provided 56 mg of oxygen and achieved a C:N:P ratio by weight of 10:4:1. Moreover, each biopellet was capped with alginate to prolong its floating time in water to 25 days. The mimicked groundwater spiked with 500 mg/L diesel TPHs (TPHd) was treated using our novelly manufactured biopellets. After 8 days of treatment, results showed a 98.8% removal of spiked TPHd at a rate of 64.1 mg/L per day, with a microbial count that increased from nearly zero to 1.0 × 107 CFU/mL. The residual TPHd constituents were mainly C13-C18. Furthermore, microbial consumption of N, P, and oxygen was noted during the 8-day period of TPHd removal. As the TPHd level increased to 1500 mg/L, the removal rate reached 45 mg/L per day, and all TPHd had been removed after 22 days.