# API PUBL 4730:2003 pdf download

API PUBL 4730:2003 pdf download.Groundwater Remediation Strategies Tool.

The locations where the transect intersects Contour lines from pfunie maps can be used to construct flow areas for the mass flux caloutations).

2. Charecterize Groundwater Flow. To characterize the specific discharge (q) across each plume transect, representative measurements are required for both the hydraul*c flow gradient (i) and the hydraulic conductivity (K) of the flow system (Where q – K x i). The groundwater flow direction and hydraulic graient for each segment of a transect line can be determined from a potentiornetric surface contour map based on static water level measurements of available sampling points. Representative measurements of the hydraulic conductivity of the groundwater-bearing unit should be obtained at one or more locations, using appropriate slug test or pumping test methods.

3. Slict Pfurne Transcts: To characterize mass flux, transects should be located at points where sufficient data are available to define affected groundwater concentrations and specific scharge, as defined in Steps 1 and 2 above. For two-dwnensional data (i.e. from single-screen monitoring wells), the transect will represent a line extending aoss the lull width of the plume, perpendicular to the direction of groundwater flow (see Figures 2 and 3). For uniform flow helds, this transect will be a straighi line, but, for converging or diverging flowlines. the transect will be curvilinear In shape. For three-dimensional data (i.e., from multilevel monitoring wells), the transect line will represent a vertical plane through the groundwater plume, positioned perpendicular to oundwater flow (see FIgures 4 and 5).

Models containing mass flux terms directly are listed below:

BIOSCREEN: An easy to-use spreadsheet-based analytical model onginaly designed to be used for BTEX plumes. It can be adapted for MTBE by using the first-order decay method to simulate b.odegradabon or by using a first order rate constant of zero if biodegradation of MTBE is not occuning at a particular site. Mass flux is eshmated from a 5×1 1 array of concentration values provided by the model, BIOSCREEN is a 2-0 model (Newell et al, 19961.

BIOCHLOR: An easy-to-use spreadsheet-based analytical model originally designed to be used for chiormated solvent plumes. As with BIOSCREEN, it can be adapted for MTBE by using the first-order decay method to simulate biodegradation or by using a first order rate constant of zero it biodegradation of MTBE is not occurnng at a particular site. BIOCHLOR allows computation of two different degradation zones, where different first-order rate constants can be entered. Mass flux is estimated from a 5×1 1 array of concentration values provided by the model, BIOCHLOR is a 2-D model (Aziz et al. 2000).

3.3 Groundwater Mass Flux CalculatIon- Extraction Well Method

An extraction well downgradient of a source zone is pumped at a rate to capture the water flowing through the source zone. After waiting f the flow field to stabilize, the mass discharge from the well(s) is measured, which is equal to the mass flux leaving the source zone.

3.4 Control Point Concentration Calculation

To estimate the source lifetime for use in Soil and groundwater modeling, two general approaches can be used (Farhat at at., 2002):

• Extrapolate concentration vs. time trends, This can be done either for natural attenuation processes, or for a reniediation System. However, several years of monitoring data are reQuired to get a trend that is robust enough to be useful.

• Use mass-based source models to estimate ren’iediation timeframes, With a source mass estimate and the mass flux leaving the source, an estimate of the time required to achieve a remediation goal can be estimated. This is the only method that will provide information on the impact of proposed remediation measures (i.e., trend data belore a remediation system is installed will not provide any information on the remediation timeirame of the system). Note that there is considerable uncertainty with estimating mass and remediation timeframes using this method, and that the final answers will likely be an orderof•magnitude endeavor.

Thés section provides a bst of references, resources, and tools for estimating reniediation timefrarnes.

4.1 Key Resources- Books

Natural Attenuation of Fuels and Chlorinated Solvents. (Wiedenieier, at at. 1999). Source mass estimation and simple models for source decay are presented in Chapter 2, Attenuation of Sources and Formation of Plumes.

4.2 Key Resources – Data Interpretation Methods

Aqueous Concentration Ratios to Estimate Mass of Multi-Component NAPL Residual In Porous Mediia. fFeenstra, 1997). This method uses the preferential dissolution of the more soluble components en a multi- component NAPL to estimate NAPI mass.

“Estimation of Residual Dense NAPL Mass by Inverse Modeling, (Butcher and Gauthier. 1994). This paper presents a method and equations for estimating NAPI, mass at a site on the measured flux of dissolved contaminants leaving the soce zone.

4.3 Key Resources – Models

SouroeDK Remeriiation Timeframe DecIsion Support System (Farhat at at.. 2002). ThIs public-domain tool contains both utilities for estimating source mass from soil and groundwater data and simple models for estimating remediation timefrarnes.