Topic Area: 2a. In Situ Bioremediation Applications

Formatted Title:

Aerobic Bioremediation with DGR for Treatment of a Phenol-Contaminated Area

Background/Objectives:

The study was conducted at a logistics terminal located in Paulínia, SP, Brazil. The company responsible for chemical product storage operations began its activities at the site in 2010, although operations had been conducted in the area since the 1980s. The site currently consists of two liquid storage tank basins and two solid storage warehouses. In December 2018, during the transfer of a phenol load, an incident involving a failure of a check valve led to a spill of the product. Phenol reached the soil and drainage channels, leading to the formation of contamination plumes in the dissolved phase in groundwater and in the adsorbed phase in the soil, with significant concentrations of the contaminant detected near Tank Basin 03. A pilot study was conducted between April and June 2024 to assess the effectiveness of different remediation techniques and to provide data for the design of a full-scale remediation system.

Approach/Activities:

Prior to the initiation of pilot testing, bench-scale tests were carried out to evaluate the growth of heterotrophic bacteria, with the aim of assessing the potential for bio-stimulation of the environment. Concurrently, drilling operations were conducted to install extraction wells, nutrient injection systems, air sparging equipment, and observation points. During the drilling operations, rapid screening tests were performed for phenol detection, enabling the determination of contamination depth and the selection of soil samples for laboratory analysis. Samples were collected throughout the borehole profiles to a depth of 20 meters. Based on the results of the rapid tests, laboratory analyses were conducted to measure parameters including total organic carbon (TOC), SVOC targets (phenol and cresols), total nitrogen, total phosphorus, and heterotrophic bacterial populations.

The trial was divided into four phases, each lasting 15 days, during which different combinations of techniques were tested: (1) pump and treat (P&T) with re-infiltration of treated effluent; (2) enhanced P&T with air sparging and re-infiltration of treated effluent enriched with nutrients; (3) enhanced P&T with air sparging and re-infiltration of treated effluent enriched with biosurfactants; and (4) enhanced P&T with air sparging and re-infiltration of treated effluent enriched with both nutrients and biosurfactants. This approach allowed for a comparison of the efficiency of each individual technique and their combinations, aiming to identify the most effective strategy for contaminant removal. The integration of different techniques and the variation of operational parameters during the pilot test were critical for validating the techniques and enhancing the accuracy of the full-scale system design.

Bruna Leite

Affiliation

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(Group 1, Poster Board #67) Aerobic Bioremediation with DGR for Treatment of Phenol-Contaminated Area