Cheremisinoff Groundwater Remediation and Treatment Technologies

1. Auflage 1998
ISBN: 978-0-8155-1733-7
Verlag: Elsevier Science & Techn.
Format: EPUB
Kopierschutz: 6 - ePub Watermark

E-Book, Englisch, 406 Seiten

This volume has been organized for practicing engineers who deal with the problems of groundwater and leachate remediation. It is intended to provide a practical overview of both techniques for evaluating groundwater quality and in selecting remediation technologies that are cost effective. Emphasis is given to advanced remediation methods.

Autoren/Hrsg.

Cheremisinoff, Nicholas P.

Inhaltsverzeichnis

1;Front Cover;1
2;Groundwater Remediation and Treatment Technologies;4
3;Copyright Page;5
4;CONTENTS;8
5;Preface;6
6;About the Author;7
7;CHAPTER1. PRINCIPLES OF GEOLOGY;14
7.1;Introduction;14
7.2;Minerals;15
7.3;Carbonates, Sulfates, and Oxides;16
7.4;Rock-Forming Silicates;16
7.5;Ores;19
7.6;Rocks, Their Origin andProperties;19
7.7;Igneous Rocks;19
7.8;Metamorphic Rocks;20
7.9;Sedimentary Rocks;21
7.10;Weathering;23
7.11;Mechanical Weathering;23
7.12;Chemical Weathering;24
7.13;Basic Soil Concepts;24
7.14;Erosion and Deposition;25
7.15;Waterborne Deposits;26
7.16;Windborne Deposits;26
7.17;Glacial Deposits;27
7.18;Geological Structure;28
7.19;Folding;28
7.20;Unconformities;30
7.21;Fractures;31
7.22;Geologic Time;33
7.23;Rock Units;33
7.24;Time and Time-Rock Units;33
7.25;Geological Maps and Cross Sections;34
7.26;Groundwater in Igneous and Metamorphic Rocks;41
7.27;Groundwater in Sedimentary Rocks;42
7.28;Groundwater in Unconsolidated Sediments;44
7.29;Relation Between Geology, Climate, and Groundwater Quality;44
7.30;Conclusions;48
7.31;References;48
8;CHAPTER 2. RELATIONSHIP BETWEEN GROUNDWATER AND SURFACE WATER;52
8.1;Introduction;52
8.2;Gaining and Losing Streams;57
8.3;Bank Storage;60
8.4;Effect of the Geologic Framework on Stream Hydrographs;60
8.5;Single-Event Hydrograph Separation Techniques;62
8.6;Depletion Curves;62
8.7;Hydrograph Separation;65
8.8;Separation of Complex Hydrographs;66
8.9;Hydrograph Separation by Chemical Techniques;67
8.10;Computer Separation Programs;71
8.11;Groundwater Rating Curve;73
8.12;Seepage or Dry Weather Measurements;82
8.13;Temperature Surveys;89
8.14;Flow-Duration Curves;90
8.15;Flow Ratios;92
8.16;References;94
9;CHAPTER 3. PRINCIPLES OF HYDROGEOLOGY;98
9.1;Introduction;98
9.2;Precipitation;98
9.3;Seasonal Variations in Precipitation;98
9.4;Types of Precipitation;99
9.5;Recording Precipitation;100
9.6;Infiltration;100
9.7;Surface Water;103
9.8;Rates of Flow;106
9.9;Stream Discharge Measurements and Records;106
9.10;Relation Between Groundwater and Surface Water;106
9.11;Groundwater;108
9.12;The Water Table;108
9.13;Aquifers and Confining Units;111
9.14;Porosity and Hydraulic Conductivity;113
9.15;Hydraulic Gradient;114
9.16;Potentiometric Surface Maps and Flow Nets;116
9.17;Calculating Groundwater Flow;122
9.18;Interstitial Velocity;128
9.19;Transmissivity and Storativity;129
9.20;Water-Level Fluctuations;130
9.21;Cone of Depression;133
9.22;Specific Capacity;135
9.23;References;138
10;CHAPTER 4. GROUNDWATER CONTAMINATION;140
10.1;Introduction;140
10.2;Sources of Groundwater Contamination;141
10.3;Groundwater Quality Problems That Originate on the Land Surface;144
10.4;Groundwater Quality Problems That Originate Above the Water Table;148
10.5;Groundwater Quality Problems That Originate Below the Water Table;152
10.6;Natural Controls on Groundwater Contamination;156
10.7;Leachate;158
10.8;Changes in Groundwater Quality;160
10.9;Cyclic Fluctuations;163
10.10;Prediction of Contaminant Migration;174
10.11;References;178
11;CHAPTER 5. GROUNDWATER RESTORATION;182
11.1;Introduction;182
11.2;Contaminant Mobility;183
11.3;Site Characterization;185
11.4;Source Control;186
11.5;Source Removal;186
11.6;Surface Runoff Controls;187
11.7;Groundwater Barriers;188
11.8;Hydrodynamic Controls;192
11.9;Groundwater Collection and Treatment;193
11.10;Pumping Systems;193
11.11;Interceptor Systems;195
11.12;Groundwater Treatment After Removal;196
11.13;In Situ Treatment;199
11.14;In Situ Physical/Chemical Treatment;199
11.15;Mobilization for Extraction;201
11.16;Detoxification;202
11.17;Biodegradation;204
11.18;Natural Subsurface Biological Activity;204
11.19;Enhanced Biorestoration;205
11.20;Treatment Trains;209
11.21;Institutional Limitations on Controlling Groundwater Contamination;210
11.22;References;211
12;CHAPTER 6. PUMP-AND-TREAT REMEDIATION TECHNOLOGY;216
12.1;Introduction;216
12.2;Data Requirements;220
12.3;Conceptual Design;234
12.4;Operation and Monitoring;257
12.5;References;262
13;CHAPTER 7. TREATING CONTAMINATED GROUNDWATER AND LEACHATE;272
13.1;Introduction;272
13.2;Variable Flows and Variable Concentrations;272
13.3;Unit Process Design Approach;277
13.4;Mass Balances;277
13.5;Unit Process Treatment Interferences;279
13.6;Life Cycle Design;283
13.7;Staging/Phased Treatment;292
13.8;Residuals Management;292
13.9;Availability of Package Plants;298
13.10;Materials of Construction and Materials Compatibility;308
14;Appendix A Compendium of Groundwater and Leachate Treatment Technologies;322
15;Appendix B Pump-and-Treat Applications;383
16;Glossary;388
17;Abbreviations;394
18;Index;397

Leseproben

2

Relationship Between Groundwater and Surface Water

Introduction

The interrelations between groundwater and surface water are of great importance in both regional and local hydrologic investigations and a wide variety of information can be obtained by analyzing streamflow data. Most commonly the surface water investigator deals with stream hydrographs, channel characteristics, geomorphology, or flood routing. Although the hydrogeologist may evaluate induced infiltration into a streamside aquifer, he is generally more interested in aquifer characteristics, such as hydraulic conductivity, thickness, boundaries, and well yields. Many hydrologists tend to ignore the fact that, at least in humid areas, groundwater runoff accounts for a significant part of a stream’s total flow.

Evaluation of the groundwater component of runoff can provide important and useful information regarding regional recharge rates, aquifer characteristics, and groundwater quality, and can indicate area of high potential yield to wells. The purpose of this chapter is to describe a number of techniques that can be used to evaluate runoff to obtain a better understanding and evaluation of groundwater resources. In particular, the following will be examined:

1. Groundwater runoff.

2. Surface runoff.

3. Regional groundwater recharge rates.

4. Determination of areas of relatively high permeability or water-yielding characteristics.

5. Determination of the background concentration of groundwater quality.

6. Estimation of evapotranspiration.

7. Determination of the percentage of precipitation that is evaportranspired, becomes groundwater runoff, or becomes surface-water runoff.

The approaches taken, admittedly some highly subjective, are based on: (1) short-term runoff events, (2) long-term hydrographs, and (3) dry-weather flow measurements. In the first approach a single event, such as a flood wave of a few hours or few days duration, can be analyzed, while the latter two approaches are based on annual stream hydrographs, flow-duration curves, or seepage runs. Short-term events may provide a considerable amount of information for a local area, while long-term events are most useful for regional studies. Streamflow may consist of several components including groundwater runoff, surface runoff, effluent, and precipitation that falls directly into the channel.

The volume of water that is added by precipitation directly into the channel is relatively small compared to the stream’s total flow. The contribution by waste effluent may or may not be significant, since it depends on the activities that are occurring in the basin. In permeable basins in humid regions, groundwater runoff may account for 70 to 80 percent of the stream’s annual discharge. The remainder is surface runoff, which originates as precipitation or snow melt that flows directly into the stream channel. This chapter is concerned largely with groundwater runoff and surface runoff and the separation of these two components.

In order to fully appreciate the origin and significance of groundwater runoff, it is first necessary to examine the regional groundwater flow system. Figure 2-1 illustrates a typical flow pattern. Particularly in humid and semi-arid regions, the water table generally conforms with the surface topography. Consequently, the hydraulic gradient or water table slopes away from divides and topographically high areas toward adjacent low areas, such as streams and rivers. Topographic highs and lows, therefore, serve as recharge and discharge areas, respectively.

Figure 2-1 Approximate flow pattern in uniformly permeable material between the sources distributed over the air-water interface and the valley sinks (after Hubbert, 1940).

Groundwater flow systems may be local, intermediate, or regional. As these terms imply, groundwater flow paths may be short, amounting to a few yards at one extreme to many miles in the regional case. Individual flow lines are, of course, influenced by the stratigraphy and, in particular, are controlled by hydraulic conductivity.

As water infiltrates a recharge area, the mineral content is relatively low. The quality changes, however, along the flow path and dissolved solids, as well as several other constituents, generally increase with increasing distances traveled in the subsurface. It is for this reason that in mineralization that takes place along longer flow paths. It must be remembered, however, that other conditions, such as soil type, solubility of the enclosing rocks, surface drainage characteristics, and waste disposal practices, may have a profound effect on water quality at any particular site.

Even streams in close proximity may differ considerably in discharge even though the size of the drainage area and climatic conditions are similar. Figure 2-2 gives the superimposed hydrographs of White River in southwestern South Dakota and the Middle Loup River in northwestern Nebraska, which are good examples. White River has a low discharge throughout most of the year, but from May to September, flash floods are common. The wide extreme in discharge is characteristic of a flashy stream.

Figure 2-2 Hydrographs of two nearby streams.

The flow of Middle Loup River is nearly constant, although from late spring to early fall higher flows may occur. These peaks, however, differ considerably from those found in White River because the increase in discharge takes place over a longer interval, the stage does not range widely, and the recession occurs more slowly. The differences in hydrographs of these two nearby rivers is puzzling, until the geology and topography of their respective basins are examined.

White River flows through the Badlands of South Dakota, an area of abrupt changes in relief, steep slopes, little vegetative cover, and rocks mat consist largely of silt and clay, bom of which may contain an abundance of bentonite. When wet, bentonite, a swelling clay, increases greatly in volume. As a result of these features, rainfall in the White River basin tends to quickly run off and there is little opportunity for infiltration and groundwater recharge to occur. Thus, intense rainstorms cause flash floods, such as those that occurred in June, August, and September. The Middle Loup basin is carved into the undulating grassland topography of the Sandhills of Nebraska, where surficial materials consist of wind-blown sand. Since the low relief, grass-covered surface promotes infiltration, precipitation is readily absorbed by the underlying sand. As a result, there is very little surface runoff and a great amount of infiltration and groundwater recharge. The groundwater slowly migrates to the river channel, thus providing a high sustained flow. In a comparison of the hydrographs of these two rivers, it is evident that the geologic framework of the basin serves as a major control on runoff. This further implies that in any regional hydrologic study, the investigation should begin with an examination of geologic maps.

Gaining and Losing Streams

Although the discharge of most streams increases downstream, the flow of some streams diminishes. These streams are referred to as gaining or losing, respectively. The hydrologic system, however, is even more complex, because a stream that may be gaining in one season, may be losing during another. Furthermore, various human activities may also affect a stream’s discharge.

Under natural conditions a gaining stream is one where the water table is above the base of the stream channel. Of course the position of the water table fluctuates throughout the year in response to differences in groundwater recharge and discharge. Normally the water table is highest in the spring, which is the annual major period of groundwater recharge. From spring to fall, very little recharge occurs and the amount of groundwater in storage is slowly depleted as it seeps into streams. Eventually, the water table may decline to the same elevation as a stream bottom, or even below it, at which time streamflow ceases except during periods of surface runoff. Following a period of recharge, caused either by infiltration of rainfall or seepage from a flood wave, the water table may again rise and temporarily contribute groundwater runoff.

Figure 2-3 shows a generalized diagram of the hydrology of a stream during two seasons of the year. During the spring, the water table is high and the gradient dips steeply towards the stream. If streamflow was measured at selected points, it would be found that the discharge increases downstream because of the addition of groundwater runoff. That is, it is a gaining stream. In the fall when the water table lies at or below the stream bottom, however, the same stream might become a losing stream. During a major runoff event the stage in the stream would be higher than the adjacent water table and water would migrate from the stream into the ground. The stream would continue to lose water until the water table and river stage were equal. When the stage declined, groundwater runoff would begin again.

Figure 2-3 The relation between the water table and stream types.

In this case the stream changed from gaining to losing and back again to gaining. Similar situations may occur over longer intervals, such as during droughts. As a...