Equations describing the transport of ion-exchanging solutes governed by local chemical equilibrium through a saturated porous medium are well established in the literature. Concentration profiles resulting from the numerical solution of the general multispecies equations typically exhibit unusual and complicated features such as multiple fronts and plateau zones. This paper presents an analytical framework, based upon the theory of chromatography, which permits a priori characterization of certain key concentration profile features. The cases studied include both homovalent and heterovalent exchange in binary and ternary systems. In order to test its validity, the chromatographic analysis is applied to a field project involving direct injection of advanced treated municipal effluent into an aquifer. All of the major features observed in the available field data are accurately predicted by the chromatographic theory.

Transport of ion‐exchanging solutes in groundwater: Chromatographic theory and field simulation

As groundwater is relied upon more and more as a source of drinking water, the practice of recharging groundwater with treated wastewater has become a more attractive means of replenishing depleted groundwater reserves. However, even extensively treated wastewater may contain pathogenic microorganisms, particularly enteric viruses. Once in the soil, these microorganisms, especially the viruses, are capable of migrating considerable distances to reach groundwater, where they pose a potential health hazard to persons consuming the water. Over one half of the waterborne disease outbreaks in the U.S. are due to the use of contaminated groundwater, and microorganisms are the cause of illness in the majority of these outbreaks. Several models have been developed to predict the behavior of microorganisms in the subsurface environment. These models range from conventional, theoretical models of contaminant transport to empirically based models using laboratory and field data. The ultimate goal of the models is to...

Modeling microbial fate in the subsurface environment

Contamination of groundwater resources from bacterial laden wastewater and effluents poses a great threat to the potability and use of these water sources. Future planning, development and management schemes must consider this topic to avoid costly and sometimes untested corrective actions. Major factors affecting the quantity and velocity at which bacteria are able to migrate through soil can be classified as (1) soil factors including particle size distribution, structure, clay content, pore size distribution and moisture regime, and (2) biological factors responsible for bacterial die-off including pH, temperature, moisture content, and nutrient supply. Past bacterial pollution problems have been shown to be localized and restricted to wells utilizing near-surface waters. The following problem areas exist and must be given special consideration in planning and development: (1) use of septic disposal systems in unsuitable soils; (2) drainage waters from wastewater application areas utilizing artificial drainage systems; (3) waste application in areas underlain by fractured crystalline rock or channelized bedrock; and (4) bacterial contamination induced over great distances by groundwater pumping.

Bacterial pollution of groundwater: A review

A comparison of the geochemical response to different managed aquifer recharge operations for injection of urban stormwater in a carbonate aquifer

Published January 1988 Facts and recommendations in this publication may no longer be valid Please look for up-to-date information in the OSU Extension Catalog: http://extensionoregonstateedu/catalog

/pdf/evaluating-coliform-concentrations-in-runoff-from-various-53pghru7c7.pdf

Evaluating coliform concentrations in runoff from various animal waste management systems

Injection of reclaimed wastewater into confined aquifers

. The Orange County Water District has conducted studies in waste water reclamation and groundwater recharge since 1965. The work has been done in three phases: (1) Study in both laboratory and pilot-scale units on the feasibility of reclaiming trickling filter effluent for injection through wells into confined aquifers; (2) long-term injection study to determine the fate of injected reclaimed water and to observe the performance of a multi-casing injection well; (3) testing alternative treatment methods in a 25,000 gpd pilot plant to solve the water quality problems which developed during the injection study.

The reclaimed trickling filter effluent was found to be injectable and did not cause excessive well clogging. The multi-casing injection wells performed very satisfactorily. The reclaimed water would be acceptable for domestic use after travel through 500 feet of a confined aquifer in that bacteria, virus and toxic material were consistently absent. However, the odor and taste which persisted in the injected reclaimed water and the high concentration of dissolved inorganics are undesirable characteristics. Methods to eliminate the odor are being tested at the present time. A cooperative project with the Office of Saline Water is under way to develop a source of desalted seawater to blend with reclaimed waste water.

G. M. Wesner

Papers

Injection of reclaimed wastewater into confined aquifers

Reclaimed waste water for groundwater recharge