Abstract Groundwater pollution is one of the most important challenges for human. In many parts world, groundwater used agriculture and even drinking, whereas natural human-made contaminants have also affected quality these waters. Therefore, monitoring evaluating quantity very important. this research, efficiency finite element method (FEM) flow Sulfate concentration transport modeling has bee...

A mathematical model has been simulated to describe natural in situ bioremediation of contaminated soil. The model equations consist of a system of three non-linear partial differential equations. Sensitivity analysis conducted by numerically solving them, has demonstrated the effect of initial contaminant concentration on the time and mechanism of remediation. The result of simulation indicate...

A system of impulsive ordinary differential equations is used to model the growth of microorganisms in a self-cycling fermentor. The microorganisms are being used to remove a non-reproducing contaminant that is limiting to growth at both high and low concentrations. Hence it is the concentration of the contaminant that triggers the emptying and refilling process. This model predicts that either...

In the process of screening a soil against a certain contaminant, we define the health-risk-based preliminary remediation goal (PRG) as the contaminant concentration above which some remedial action may be required. Thus, PRG is the first standard (or guidance) for judging a site. An overestimated PRG (a too-large value) may cause us to miss some contaminated sites that can threaten human healt...

Analytical study of contaminant transport from a finite source in a finite-thickness aquifer is most useful in hydrological and environmental sciences and engineering but rarely investigated in previous studies. This paper provides analytical solutions of contaminant transport from one-, two-, and three-dimensional finite sources in a finite-thickness aquifer using Green's function method. A li...

Two outfalls, each with given tidally averaged discharge rates, are discharging into the same narrow (rapidly mixed) estuary. The lowest achievable concentration peak (in position and time) for the principal contaminant species is attained with an ‘all or nothing’ discharging policy. The discharge rate is either ‘all’ that is allowed by concentration peak or is nothing. The ‘nothing’ regime cor...

Conventionally, the "breathing zone" is defined as the zone within a 0.3 m (or 10 inches) radius of a worker's nose and mouth, and it has been generally assumed that a contaminant in the breathing zone is homogeneous and its concentration is equivalent to the concentration inhaled by the worker. However, several studies have mentioned that the concentration is not uniform in the breathing zone ...