Evaluation of methods for water and non-volatile LNAPL content measurement in porous media

Abstract

Proper characterization of contaminants in subsurface helps to clean up effectively the contaminated sites. In this study, different methods were used to quantify non-volatile light non-aqueous phase liquid (LNAPL) and water from sample columns subjected to different water to LNAPL ratios. The objective of the study was to evaluate methods for porous media water and LNAPL contents analysis. The liquids were sampled from the sample columns using activated carbon pellets (ACP). Sample columns water content was also measured using soil moisture sensors. Dielectric mixing model (DMM) was evaluated for the estimation of LNAPL content after water and LNAPL contents of the sample columns were determined through gravimetric analysis method. The result shows that it was possible to sample both water and LNAPL using ACP proportionally but with high standard deviations. It also shows that more liquid was sampled from sample columns subjected to only one liquid compared to sample columns subjected to two liquids. On the other hand, analysis of water and LNAPL using gravimetric analysis method gave the best result although the presence of LNAPL resulted in underestimation of water content at higher LNAPL contents. Meanwhile, the presence of LNAPL modified the bulk relative permittivity (ε<sub>a</sub>) of the sample columns and resulted in overestimation of water contents measured using soil moisture sensors at higher LNAPL content. The modification of ε<sub>a</sub> was used for the estimation of LNAPL using DMM. The evaluation of the model with known water and LNAPL contents and in estimating the LNAPL content of the other sample columns shows that the model could be used for the proper estimation of LNAPL in porous media.

WITHDRAWN: Effect of unsaturated flow on the occurrence and movement of light nonaqueous phase fluids

“…The complexity of LNAPL migration in groundwater environmental systems is mainly manifested by the complexities of in uencing factors as well as migration processes. Various factors, such as the thickness of the aeration zone and aquifer, characteristics of the soil in the stratum, organic matter content, depth and ow direction and velocity of groundwater, and hydrogeological conditions in which the groundwater is located all affect the migration process, migration rate, migration volume, and the occurrence state of LNAPLs in the groundwater environment (Chala et al, 2019). In addition, the mutual transformation between surface water and groundwater and the in ltration of rainwater after precipitation can trigger an imbalance in groundwater supply and discharge, resulting in groundwater uctuations and causing a redistribution of organic matter in the subsurface environment, thereby complicating the migration and distribution of LNAPLs in the aeration zone.…”

“…Chemically contaminated sites account for 44.1% of the Beijing-Tianjin-Hebei Construction Land Soil Pollution Risk Control and Remediation List, with petroleum hydrocarbons accounting for up to 42.10% (Yuhong et al, 2022). In 2009, a diesel spill occurred in the Weinan branch of the China National Petroleum Corporation's Lanzhou-Zhengzhou-Changsha oil pipeline during the commissioning of the sub-transmission, which resulted in around 100 m 3 of diesel owing into the Chishui River, a tributary of the Wei River. According to Russian scientists, 7% of global crude oil extracted each year enters the environment and contaminates soil and groundwater.…”

The Assessment of Relative Permittivity on Diesel Vapour in the Moisture Content of Terap Red Soil by Ground Penetrating Radar

“…36 However, LNAPLs and DNAPLs compounds presented significantly low electrical conductivity. 37 With that being said, GPR was convenient for resistive environments.…”

Valorisation of Pineapple Cannery Waste as a Cost Effective Carbon Source for Poly 3-hydroxyabutyrate (P3HB) Production

“…The modified gravimetrical method described by Chala et al (2019) [ 25 ] was used to determine the extracted PHAs. The sequence steps were explained as follows: wet cell mass or cell pellet obtained from centrifugation was treated with 3% ( v / v ) sodium hypochlorite (commercial grade bleach), incubated at 37 °C and stirred for 1 h. Thereafter, chloroform was added into mixed solution and was then stirred at 50 + 5 °C for 3 h. An upper phase of chloroform was separated and evaporated.…”