2.8 Elements and Compounds on Abandoned Industrial Sites

Ulrich Förstner and Joachim Gerth

1 Introduction

Abandoned contamination sites include old garbage dumps and industrial production residues,

contaminants from industrial facilities, areas in the vicinity of smoke stacks and discharge

pipes, the concomitant contaminations and consequences of two world wars, military

installations of the past and present, leaking wastewater lines, and buildings that were

constructed with materials that have adverse effects on human health.

From a regulatory perspective, abandoned landfills are "abandoned and inactive waste disposal

sites, regardless of the point in time at which they were rendered inactive, illegal waste

disposal sites that existed before the enactment of the respective waste laws (so-called "illegal

dumps") and "other abandoned/inactive dumps or fills"; whereas abandoned contamination

sites are "sites of inactive installations that handled environmentally hazardous substances"

(i.e., these are primarily old industrial and commercial facilities).

On such industrial sites, production residues were often superficially buried, or production

input, intermediate, and end products were stored without any protective measures (former gas

utilities, insecticide plants). Other subsurface contamination was caused by leaking pipelines

used for chemicals, petroleum products, etc., or leaking above ground storage tanks (ASTs),

e.g., abandoned refineries and airports. Oil and gasoline leakage from underground storage

tanks (LUSTs) has caused considerable soil contamination (e.g., gas stations). Soil contamina-

tion was also caused, e.g., in the port of Hamburg, Germany, by the effects of war, where

organic chemicals and petroleum products from destroyed above-ground tanks and/or opera-

2

ting facilities seeped into the subsurface (Förstner 1998). Table 2.8-1 gives an overview on

typical industrial sites and their relevant metal contaminants (Anonymous 1990, 1995).

Table 2.8-1 Suspected abandoned contamination sites and possible relevant substances

(Anonymous 1990, 1995)

batteries, accumulators

basic inorganic chemicals

fertilizer

plastics

paints and coatings

plant protection, herbicides,

pesticides, etc.

ammunition & explosives

coal mines, gas works, coking

plant

crude oil processing/

petroleum storage (incl. waste

oil)

antimony, arsenic, lead, cadmium, chromium, fluoride, copper, nickel, mercury, acids/bases,

selenium, zinc

antimony, arsenic, beryllium, lead, cadmium, chromium, copper, nickel, mercury, acids/bases,

selenium, thallium, vanadium, zinc

arsenic, cadmium, copper, acids/bases, thallium

lead, cadmium, chromium, acids/bases, selenium, zinc

antimony, arsenic, lead, cadmium, chromium, copper, mercury, acids/bases, selenium,

thallium, zinc

arsenic, lead, chromium, copper, mercury, selenium, thallium, zinc

antimony, arsenic, lead, chromium, copper, mercury, acids/bases

arsenic, (asbestos), lead, chromium, acids/bases

arsenic, chromium, copper, lead, nickel, acids/bases, selenium, tetraethyl lead, toluene,

vanadium, zinc

iron and steel production

nonferrous refinery

nonferrous metallurgical plant

surface treatment and

hardening of metals

metal foundries

working, treating, and

processing of wood

paper, cardboard, and textiles

processing of rubber, plastics,

and asbestos

manufacturing and processing

of leather

edible oils and fats

junk yards, salvage yards

airports

gas stations

antimony, arsenic, beryllium, cadmium, chromium, copper, lead, mercury, nickel, acids/bases,

selenium, thallium, vanadium, zinc

antimony, arsenic, beryllium, cadmium, chromium, copper, lead, mercury, mineral oil, nickel,

acids/bases, zinc

acids/bases, antimony, arsenic, beryllium, cadmium, chromium, copper, lead, mercury, nickel,

selenium, thallium, vanadium, zinc

antimony, arsenic, lead, cadmium, chromium, copper, nickel, mercury, acids/bases, selenium,

zinc

antimony, arsenic, lead, cadmium, chromium, fluorides, copper, nickel, mercury, selenium,

zinc

arsenic, acids/bases, chromium, copper, nickel, mercury, zinc

antimony, acids/bases, chromium, copper, lead, mercury, thallium, zinc

antimony, arsenic, cadmium, chromium, copper, lead, mercury, zinc

arsenic, chromium

acids/bases, nickel

cadmium, chromium, lead, zinc

lead alkyls, bromine compounds

3

leaded alkyls

2 Treatment of Contaminated Industrial Sites

What should be done once soil contamination on abandoned industrial sites has been discove-

red? Here are some of the available alternatives (Thomé-Kozmiensky 1989):

Leaving the contaminated soil in place and limiting the use of the site;

Capping or encapsulating the soil in place with impermeable material and applying a layer

of clean topsoil;

Excavating the contaminated soil and disposing of it at a solid or hazardous waste landfill;

Remediating the contaminated soil in-situ, "on-site," i.e., at the site, or off-site, at a facility

located elsewhere.

The choice of the remediation method is also of importance for the later use of the site or of

the soil. The intensity of handling, i.e., changing the soil, increases from "biological

treatment," to "soil flushing" to "thermal soil treatment". It is possible for some biological and

flushing methods to drastically change the original chemical soil properties by adding

chemicals and nutrients and by enhancing the growth of microorganisms; the physical soil

properties, however, remain the same and the disturbed soil biology can regenerate within a

few years and will again adapt to site conditions. Subsequent land use restrictions can be the

consequence of possible groundwater contamination from applying nitrates and from the

release of nitrogen from the endogenous decomposition of microorganism ( Slenders et al.

1997; Stegmann et al. 2001).

In the following paragraphs two groups of treatment techniques are described, which were

applied for metal contamination in abandoned industrial sites. It should be noted, however,

that compared to the treatment of organic contaminants, mainly by biodegradation, the results

4

of these procedures may be limited, either due their low efficiency for extracting critical metals

pollutants (e.g., during chemical treatment) or due to negative side effects, such as increase in

volume and consumption of costly additives (e.g., during solidification and stabilization).

2.1 Solidification/Stabilization

U.S. Environmental Protection Agency (EPA, Anonymous 1986) defines these two terms as

waste treatment methods that have the following objectives: (1) to improve manageability and

physical properties, e.g., by the sorption of free liquids; (2) to reduce the surface area of waste

that can be caused by contaminant migration and/or loss; (3) to limit the solubility of

hazardous waste components, e.g., by pH adjustment, or by sorption processes:

Solidification describes a process where a bonding agent is mixed with the waste material

to create a mechanically solid product. The associated testing methods usually originate in

soil mechanics and soils testing (strength, permeability, temperature and moisture resistan-

ce, etc.) Together with its technical implementation, this term describes primarily a method

of waste treatment.

Stabilization describes the goal of solidification as it relates to harmful components, which

is, to convert the waste material into a chemically more stable form and to limit solubility

of its hazardous constituents. The degree of stabilization is determined by leach tests, and

studies of sorption, diffusion, and volatilization. At best, stabilization results in

immobilization through solidification: the migration of contaminants from the wastes'

surface area is prevented or at least minimized.

Inertization describes the mechanisms that cause stabilization or immobilization. The type

of inertization is determined by special physical (e.g., electron-optical or X-ray) or

chemical methods (e.g., for heavy metals with valence-specific sequential extractions.

Some solidification methods serve only to improve transportability and storability. To do that,

5

liquid and pasty wastes are converted so that any seepage of liquids is prevented and that

above-ground storage is allowed. In other cases, the goal is material recovery (recycling),

especially for large-volume waste materials such as dredge spoils and power plant fly ash.

The processes and techniques of stabilization/solidification (S/S) have matured into an

accepted part of environmental technology (Means et al. 1995; Conner and Hoeffner 1998a).

There are different generic and proprietary S/S processes that can be conveniently categorized

as follows:

Chemical processes – cement-based, pozzolan-based, lime-based, phosphate-based,

additive intensive;

Physical processes – macroencapsulation/containerization, non-chemical microencapsula-

tion;

Thermal processes – thermoplastic polymer encapsulation, vitrification.

For metals, the primary factors affecting immobilization are pH control, chemical speciation,

and redox potential control. For organics, immobilization of constituents can be broken down

into two primary classifications: reactions that destroy or alter organic compounds, and physi-

cal processes such as adsorption and encapsulation (Conner and Hoeffner 1998b).

S/S processes develop a wide variety of strength and durability values, depending on many

factors: waste type, water content, reagent type, reagent addition ratio (mix ratio), curing time,

and temperature. Contrary to the opinion held by many, rock-hard solids are not always

desirable. In landfill operations, a friable, compactable material is usually preferable, and low

permeability, while desirable from a leaching point of view, may make operation of a landfill

difficult in wet weather (Conner and Hoeffner 1998b).

The compatibility of typical metal waste components with solidification agents is discussed by

6

Wiedemann (1982), Wiles (1987) and Conner and Hoeffner (1998a,b) (Table 2.8-2).

Cement (Portland cement) consists of a mixture of oxidized calcium, aluminum, and silici-

um compounds which are induced into a reactive condition in a cement kiln, and, when

mixed with water, form hydrated aluminates and silicates, become solidified and is water

resistant. Absorbent materials such as diatomaceous earth and powdered clay can be added

to absorb certain liquids. The immobilization of multi-valent metal ions in the form of

slightly soluble hydroxides or alkaline carbonates is promoted by a high pH. Here is the

main area of use for these comparatively expensive additives whose advantages include a

variety of applications and proven methodologies. Furthermore, it is advantageous that

sludge dewatering is not necessary: e.g., the treatment of flotation sludge in its original

condition with cement leads to rapid settling and solidification of particles; the excess

water is clear and can be drawn off. The disadvantages include the presence of components

in the waste, such as sulfate and organic substances, and possibly sodium, manganese, lead,

and zinc, which compromise the solidity of the products.

Two reactions can convert alkali silicate glass into a solid mass with which contaminated

sludges can be bound: (1) by adding acid to form silica gel, whereby the evaporation of

water does not occur (alternative to vaporization!); and (2) reaction with multi-valent metal

ions (e.g., calcium chloride) while forming aqueous metal silica gel, where heavy metals

are precipitated and are mechanically bonded into the gel structure. The CHEM-FIX-

Process is primarily used in the U.S. for inorganic contaminants; the Belgian SOLIROC-

Process contains additives to make it usable for the solidification of organic wastes.

The pozzolanic effect, which describes the specific curing behavior of flyash, cement

dusts, and certain steel works byproducts, is based on the reaction of silicate and aluminous

materials with quick lime. Here too, as with the above mentioned additives, a higher pH

causes the precipitation of metal hydroxides and carbonates. The British SEALOSAFE-

Process uses flyash plus Portland cement, or alkali silicate glass and Fe/Al hydroxides to

solidify a broad spectrum of wastes. In the POZ-O-TEC-Process, the wastes from fluegas

scrubbers are solidified together with grate ash and flyash. The pozzolanic processes have

the advantage of excellent long-term stability, however, they solidify rather slowly and are

susceptible to acids.

7

Lime in the form of calcium oxide (quick lime) or calcium hydroxide has long been used

to chemically stabilize soil. Some reactions represent a "pozzolanic effect". Quick lime that

has been treated with reaction inhibitors (hydrophobic) is used especially for the

solidification of oily sludges and contaminated soils (Bölsing 1986).

Table 2.8-2 Solidification/stabilization processes and agents for metal-rich wastes (after

Anonymous 1990)

Material Additives Binding Mechanism Potential Applications

Cement (Portland-

cement)

water, perhaps

bentonite

stabilization,

sometimes fixation

subsurface injection,

watery sludges

Liquid Glass (sodium

silicate); pulverized

silicate

not known (nk) compaction soil compaction

(subbase of

contaminated soil)

Lime hydrophobing agent dispersion oil sludges, leachate

Brown Coal Power

Plant Ash

scrubber residues,

desulfurization

wastewaters

solidification,

stabilization

brown coal

combustion residues

and desulfurization

residues

Glass (electrical

energy)

electrolytical salts vitrification "in-situ" wastes and

soils

When evaluating these processes, the question of bonding stability becomes paramount. While

with inorganic contaminants such as heavy metals, the addition of a few additives permits a

completely different form of contaminant fixation, during the solidification of organic compo-

nents, a bonding change in critical contaminants is often not intended. Overall it should be

concluded that little practical experience is available of the long-term behavior of most

solidification/stabilization products. Should tests reveal that the immobilizing effect of a

bonding agent is insufficient, the large blocks of solidified material would, in effect, have to be

leveled using mining techniques, or would need to be encapsulated (Anonymous 1995).

2.2 Washing and Electrochemical Methods

8

All remediation methods which remove, convert, or destroy contaminants in a matrix, i.e., soil

or groundwater, except thermal and biological methods, are defined as chemical-physical

methods. It is possible to pursue a variety of strategies with chemical-physical methods (Offutt

et al. 1988):

Generation of small quantities of concentrated contaminants through conversion and

separation;

Generation of relatively large quantities of diluted contaminant streams from which

concentrated contaminants have to be separated before disposal.

Typical examples of separation methods include washing and extraction processes used for

relatively highly concentrated liquids and sludges requiring disposal. The endproducts of the

washing process are generally sludges, saturated absorbents or distillation residues from the

regeneration of extracting agents. Typical examples of division methods include leaching of

contaminants from native soil ("in-situ") with the generation of relatively low contaminated,

treatable wastewater, or airstripping (extracting soil vapor) with subsequent adsorptive

scrubbing. The endproducts of this scrubbing process are similar to those produced in the

concentration process.

In extractive soil washing, the contaminated materials are cleaned with detergents. The advan-

tage of this process is essentially that no biologically dead soil is generated, and when the

extraction is done correctly, inorganic contaminants can also be efficiently removed. The

application of "on-site" chemical washing and flushing methods, which is practiced almost

exclusively, requires several process stages. First the material is homogenized, reduced in size,

or divided into fractions through screening. The actual leaching process takes place in a mixer;

particularly favorable is the contact between the solids and the solution in a fluidized bed

9

reactor. In the next stage, the solution and the decontaminated solids must be separated - e.g.,

in settling ponds, with filter presses, in hydrocyclones, or in centrifuges, etc. Post-treatment

generally consists of a washing process, where the generated solution is processed: precipi-

tation of inorganic components, volatilization and adsorption, incineration, chemical or micro-

biological treatment of organic components, and, possibly, the recovery of the extraction agent

(Rulkens and Bruning 1995).

The mechanical and physical pretreatment processes include screening and size-reduction,

density and particle separation in settling ponds, as well as hydrocyclone and fluidized bed

processes, dewatering by using centrifuges or filter presses, and removal of volatile

compounds by using adsorptive or thermal methods. New developments, where chemical

extraction agents are replaced by mechanical energy, use water as a cost-effective solvent

which, unlike the chemical solvents, does not pollute the environment. The sufficiently long

treatment of each part of the soil particle can be achieved by feeding the soil/water mixture

through a screw conveyor which transmits additional axial movement to the particles.

The properties of water as a washing agent and a solvent can be enhanced with additives.

Several types of additives include: (i) surfactants that improve the wettability of the soil

components and improve the solubility of lipophilic impurities, (ii) complexing agents which

convert heavy metals and their insoluble compounds into water soluble compounds, (iii)

flotation agents (collectors and foamers), which convert certain insoluble substances into an

separable phase, and (iv) acids or bases for pH control which is necessary for the stability of

compounds and for the selectivity of the flotation processes (Venghaus and Werther 1998,

Wilichowski 2001).

Hydrochloric, sulfuric, and nitric acids are used in soil remediation to extract metals; because

10

of the good solubility of basic salts, e.g., lead and zinc, it is also possible to use treatment with

sodium hydroxide. Cyanides can also be converted with NaOH; however, experience has

shown that the treatment of iron cyanide in fines is difficult. The treatment of wastewater

generated during the treatment of contaminated soil employs the same techniques as those

used to treat industrial wastewater. Calcium oxide is most often used for the precipitation of

metals as this process also removes sulfates, fluorides, phosphates, and arsenates. Most

effective in the elimination of heavy metals is sulfidized precipitation, which can be initiated

by sodium or iron sulfide, among others. The precipitation reactions - except for the sulfidized

precipitation - are sometimes inhibited by strong complexing agents such as EDTA. On the

other hand, organic complexing agents can eliminate certain heavy metals; e.g., mercury can

be effectively removed from wash water with mercaptan (Reimann 1984).

Contrary to solvent extraction, in soil washing processes the pollutants are not attacked

directly. Therefore, soil washing processes are suitable for the treatment of soils contaminated

with both organic pollutants and heavy metals. However, a fairly high proportion of the soil

remains as a highly contaminated fine fraction and has to be disposed of.

Although soil washing has proved to be a successful technique for soil remediation for the last

15 years, the initial hope that soil washing would find a considerable market has not been

realized. After a fairly strong boom in the beginning of the Nineties, both the state of the

market and the technological development has now stagnated. The main reasons are the costs

of soil remediation, as well as the possibilities of alternative utilization of contaminated soils

(Wilichowski 2001).

11

Electrochemical Remediation

Heavy metals and other contaminants can be removed from the soil and groundwater with the

help of electro-kinetic phenomena (electrosmosis, electrophoresis, electrolysis). In electro-

chemical remediation processes, a continuous electrical field is generated with electrodes that

are inserted into the contaminated soil (Shapiro et al. 1989, Ottosen et al. 1995, Hansen et al.

1997). Laboratory and pilot tests have been conducted, for example, with acetic acid as clea-

ning solution (Renaud 1990). With electrochemical treatment, toxic hexavalent chromium has

been reduced to a stable non-toxic trivalent species (Haus and Czurda 2000).

3 Natural Attenuation of Inorganic Pollutants on Industrial Sites

(J.Gerth)

References

Anonymous (1986) Handbook for Stabilisation/Solidification of Hazardous Waste. U.S. Envi-

ronmental Protection Agency, EPA/540/2-86/001. Cincinnati

Anonymous (1990) Special Expert Report „Altlasten“ from December 1989. Der Rat von

Sachverständigen für Umweltfragen. Metzler-Poeschel Verlag Stuttgart

Anonymous (1995): Special Expert Report „Altlasten II“. Der Rat von Sachverständigen für

Umweltfragen. Metzler-Poeschel Verlag Stuttgart

Anonymous (1999) Use of Monitored Natural Attenuation at Superfund, RCRA Corrective

Action, and Underground Storage Tank Sites. OSWER Directive 9200.4-17P. U.S.

EPA, Office of Solid Waste and Emergency Response. Washington DC

Anonymous (2000) Natural Attenuation for Groundwater Remediation. National Research

Council, U.S. 229 p. National Academy Press, Washington DC

12

Bölsing F (1986) Bodenaufbereitung mit Hilfe dispergierender chemischer Reaktionen. In:

Fachseminar zur Bodensanierung und Grundwasserreinigung – Wiedernutzung von

Altstandorten. pp. 277-310. Zentrum für Abfallforschung, TU Braunschweig

Conner JR and Hoeffner SL (1998a) The history of stabilization/solidification technology. Crit

Rev Environ Sci Technol 28: 325-396

Conner JR and Hoeffner SL (1998b) A critical review of stabilization/solidification

technology. Crit Rev Environ Sci Technol 28: 397-462

Förstner U (1998) Integrated pollution control. 505 p. Springer-Verlag Berlin New York

Förstner U and Gerth J (2001) Natural attenuation – non-destructive processes. In: Stegmann

R, Brunner G, Calmano W, Matz G, eds. Treatment of contaminated soil – fundamen-

tals, analysis, applications, pp. 567-586. Springer-Verlag Berlin Heidelberg New York

Hamon RE, McLaughlin MJ and Cozens G (2002) Mechanisms of attenuation of metal availa-

bility in in situ remediation treatments. Environ Sci Technol 36: 3991-3996

Hansen HK, Ottosen LM, Laursen S and Villumsen A (1997) Electrochemical analysis of ion-

exchange memberanes with respect to a possible use in electodialytic decontamination

of soil polluted with heavy metals. Separation Sci Technol 32: 2425-2444.

Haus R and Czurda K (2000) Field scale study on in-situ electro-remediation. In:

Contaminated Soil 2000, pp. 1052-1059. Thomas Telford Publ. London

MacDonald JA (2000) Natural attenuation for groundwater cleanup. Environ Sci Technol 34:

346A-353A

Means JL, Smith LA, Nehrung KW, Brauning SE, Gavaskar AR, Sass BM, Wiles CC and

Mashni C.I. (1995) The application of solidification/stabilization to waste materials.

334 p. Lewis Publ. Boca Raton

Offutt CK et al. (1988) Superfund ’88. Proc. 9th

National Conference on Hazardous Materials

Control Research Institute. Washington D.C.

Ottosen L, Jensen JB, Villumsen A, Laursen S, Hansen HK and Sloth P (1995) Electrokinetic

remediation of soil polluted with heavy metals – experiences with different kinds of

13

soils and different mixtures of metals. In: Van den Brink, WJ, Bosman R, Arendt F,

eds. Contaminated Soil ’95, pp. 1029-1038. Kluwer Academic Publ. Dordrecht

Reimann DO (1984) Reinigung von Rauchgaswaschwässern im MHKW Bamberg mit

Schwerpunkt auf der Quecksilbereliminierung durch TMT-15-Zugabe. VGB

Kraftwerkstechnik 64: 230-235

Renaud PC (1990) In-Situ Extraktion von Schadstoffen aus Sondermülldeponien durch

Elektroosmose. In: Arendt F, Hinsenveld M, Van den Brink WJ, eds.

Altlastensanierung ’90, pp. 1205-1216. Kluwer Academic Publ. Dordrecht

Rulkens WH and Bruning H (1995) Clean-up possibilities of contaminated soil by extraction

and wet classification: Effect of particle size, pollutant properties and physical state of

pollutants. In: Van den Brink WJ, Bosman R, Arendt F, eds. Contaminated Soil ’95, pp.

761-773. Kluwer Academic Publ. Dordrecht

Shapiro AP, Renaud PC and Probstein RF (1989) In-situ extraction of contaminants from

hazardous waste sites by electroosmosis. In: Muralidhara HS, ed. Solid/liquid

separation: Waste management and productivity enhancement. pp. 346-353. Batelle

Press, Columbus/Ohio

Slenders H, Wit H de, Staijn B and Kok T (1997) Dutch Handbook on soil remediation tech-

niques; an evaluation of remediation techniques. Final Report 1057570. 5. Dec. 1997.

Stegmann R, Brunner G, Calmano W and Matz G (eds., 2001) Treatment of contaminated soil

– fundamentals, analysis, applications. 658 p. Springer-Verlag Berlin Heidelberg New

York

Thomé-Kozmiensky KJ (1989): Techniken zur Sanierungs von Altlasten. In: Thomé-

Kozmiensky KJ, ed. Altlasten 3. pp. 1-30. EF-Verlag für Energie und Umwelttechnik

Berlin

Venghaus T and Werther J (1998): Flotation as an additional process step for the washing of

soils contaminated with heavy metals. In: Contaminated Soil ’98, pp. 479-490. Thomas

Telford Publ. London

14

Wiedemann HU (1982) Verfahren zur Verfestigung von Sonderabfällen und Stabilisierung

von verunreinigten Böden. Bericht des Umweltbundesamtes, 1/82. E. Schmidt Verlag,

Berlin

Wiles CC (1987) A review of solidification/stabilization technology. J Hazard Mater 14: 5-21

Wilichowski M (2001) Remediation of soils by washing processes – an historical overview.

In: Stegmann R, Brunner G, Calmano W, Matz G, eds. Treatment of contaminated soil

– fundamentals, analysis, applications, pp. 417-433. Springer-Verlag Berlin Heidelberg

New York