- 1. IntroductionImportance of GroundwaterSources of Groundwater
ContaminationPrevention from Groundwater PollutionParticipation of
Industries and CommunityGroundwater RemediationConventional and
Innovative Remediation TechniquesTypical Groundwater
ContaminantsPractical Remediation TechnologiesRoyal Commission
Environmental Regulations for Groundwater PreventionConclusion
2. Groundwater is water present below the ground surface
thatsaturates the pore space in the subsurface.At least 50% of the
world population depends on groundwater as asource of drinking
water.Other uses of groundwater includes Irrigation of crops,
Industrialuses etc.Groundwater is a part of natural water cycle
therefore, it can spreadthroughout the cycle and if contaminated,
can cause damage toother entities ( Sea life, lakes, human health
etc)Groundwater can be polluted / contaminated as a result of
HUMANactivity and Natural conditions.Contaminations found in the
groundwater cover a broad range ofphysical, chemical (Organic &
Inorganic), bacteriological andradioactive parameters. 3. Leaking
Fuel and Chemical TanksImproper use ofcontaminated waterIndustrial
Chemical spills Industrial EmissionsExtensive use of
Pesticides,Badly Managed Landfill Herbicides and fertilizers
Drainage of house hold chemicals 4. Once Groundwater gets
contaminated, it may be difficult and expensiveto clean it up,
therefore,Thebest way to deal withgroundwater contamination is not
tocontaminate it in the first place 5. Participation of
Industries:Minimize use of Toxic / Hazardous Raw MaterialsMaintain
Integrity of the Storage Tanks, Pipelines, surface
impoundmentsAdopt Good Engineering Practices for selecting proper
material for tanksand pipes.Implement monitoring programs: Leak
Detection and repair program, spilldetection, spill control,
emergency response plan etc.Manage Properly: Waste materials, their
transport and disposal.Install Monitoring WellsMonitor
Periodically: Groundwater quality 6. Participation of
Community:Minimize use of house hold chemicals containing Hazardous
substances.Avoid draining chemicals, motor oil, insecticides in
community areas.Reduce pesticide applicationUse proper procedures
for handling chemicals (Paints, Pesticides,Insecticides, polishing
materials, cleaning chemicals and detergents).Immediately clean any
spills and report any leakages to concerneddepartment. 7.
Groundwater remediation is the process that is used to remove
pollution fromgroundwater.Pollutants and contaminants can be
removed from groundwater by applying varioustechniques thereby
making the groundwater safe for use.Groundwater remediation
techniques are mainly divided into two technologies: Ex-Situ
Technologyand In-Situ TechnologyEx-Situ Technology involves
treatment of groundwater by de-watering the polluted aquifer
(pumping out), then treating the water onsurface by Physical,
chemical or biological technology and finally re-injecting the
treated water to the aquifer.In-Situ Technology involves treatment
of groundwater withinthe aquifer (in the sub-surface) by using
thermal, chemical andbiological treatment technology. 8. Ex-Situ
Technology:Extraction of groundwater from aquifer , treat above
ground. and return the treatedwater to the aquifer. Extraction is
done by pumping groundwater from the well ortrench and treat them
with a variety of techniques such as :Stream strippingInvolves
treatment by introducing steam which extract the contaminants from
thepumped out groundwater. The extracted steam (along with
contaminants can berecovered from the condensate or treated further
by incineration.Oxygen SpargingInvolves introduction of
oxidizing/reducing agents ( O3, H2O2, Hypochlorite) tochemically
convert the toxic contaminants to less toxic
compounds.BioremediationInvolves treatment of pumped up groundwater
by air (biodegradation) with carefulcontrol of moisture, heat
nutrients, oxygen and pH.Carbon AdsorptionInvolves passing the
contaminated pumped up groundwater through activatedcarbon column
in which contaminants gets adsorbed. 9. Ex-Situ Technology 10.
In-Situ Remediation Technology:Involves treatment of groundwater
(in-place) without extracting the water from aquifer. There
areseveral treatment techniques used for in-situ groundwater
treatment such as:Air Sparging:Involves the injection of
contaminant-free air into the subsurface saturated zone, enabling a
phasetransfer of hydrocarbons from a dissolved state to a vapor
phase.Bioremediation:Involves injection of oxygen to enhance the
biodegradation. This treatment also combines injection ofdegrading
bacteria and nutrients into aquifer to stimulate
biodegradation.In-well air stripping:Involves injection of air in
double screened well, lifting the water up the well and force it
out in upperscreen. VOCs in the contaminated water are transferred
from dissolved phase to vapor phase in airbubbles and drawn off and
treated.Chemical Oxidation:Involves Reduction-Oxidation reactions
that chemically converts hazardous contaminants to less
toxiccompounds. Cyanide oxidation and de-chlorination are the
typical examples of chemical oxidation.Thermal Treatment:Involves
increase in temperature of the source zone to increase the mobility
of the pollutants. Themobility facilitate removal of pollutants and
can also results in In-Situ destruction of
contaminants.PhythoremediationIt involves the use of macroscopic
plants to destroy, remove, immobilize and treat contaminants.This
process does not use microorganisms. 11. In-Situ Bioremediation 12.
The selection of the remedial technology depends upon
severalparameters such as:Contaminant Profile:Types of compounds (
DNAPL, LNAPL, Ammonia, Virus, Bacteria)Quantity and Solubility (
Solubility in Water)Toxicity and volatility ( VOCs , SVOCs, Metals,
etc)BiodegradabilityAquifer Profile:Soil Type (permeability,
homogeneity, chemistry, confined or open, etc)Groundwater Flow
directionWater Table locationRecharge location ( seasonal
Rainfall)Feasibility Profile:Cost of technologyTime of completion
13. Several man made chemicals are referred to as
Groundwatercontaminants because of their extensive use, accidental
spills andleaks, mismanagement and illegal dumping. Some of the
popularcontaminants are the following:DNAPL (Dense Non Aqueous
Phase Liquids )LNAPL (Light Non Aqueous Phase Liquids)Inorganic
Chemicals ( Ammonia, Cyanide, Fluoride)MetalsBacteria and Viruses
14. DNAPL :Dense Non Aqueous Phase Liquids are organic compounds
heavier thanwater and having less absolute solubility. These
compounds includechlorinated solvents (EDC) and halogenated
aromatics (TCB)DNAPLs migrate very fast through the soil formation
and reach watertable because of their high density and low
viscosity. They sink steeply tothe bottom of the aquifer till they
reach the impermeable bed rock.Treatment of DNAPLThe following
types of technologies are increasingly being used to treat DNAPLs:
In situ thermal treatment In situ chemical oxidation
Surfactant/co-solvent flushing In situ bioremediationGround water
extraction (P&T or recirculation) ExcavationContainment
(Engineered caps and slurry walls). 15. LNAPLLight Non Aqueous
Phase Liquids are organic compounds lighter thanwater and having
low solubility. These liquids include Gasoline, fuel oiland other
petroleum products.LNAPL Remediation:Remediation may require the
use of more than one technology.It is likely that several
remediation techniques, used in series and/orparallel applications,
will be required for maximum contaminant removal.This collaborative
effort may be referred to as a treatment train approach.A
conceptual example of a treatment train which might be effective at
anLNAPL site includes:Pump and Treat for mobile LNAPL removal
followed by vaporextraction for removal of residual LNAPL
.Additional technologies such as bioremediation might be used to
furtherreduce contaminant concentrations. 16. Contaminant Main
Source Treatment TechnologyDegreasing of Metal and Electronic
parts, Pump and TreatTrichloroethylene Extract for oil and waxes,
fumigant, carries in Activated Carbon(TCE) paints and
adhesivesThermal and BiologicalMTBE can be released to groundwater
byAir Spargingleaking underground storage tanks and In-Situ
oxidation ( H2O2 and Fe)MTBEpiping, atmospheric deposition, spills
during Bioremediation/Bioaugmentationtransportation, and leaks at
refineries Pump and Treat.From EDC and VCM Plants, storage tanks,
In-situ Bioremediation.EDC (DNAPL) pipelines etc.Gasoline and other
petroleum fuels tanks, In-situ BioremediationGasoline (LNAPL)petrol
stations, storage tanks and pipelines. Vapor extractionAmmonia
Storage Tanks, Landfill leaks,Pump and TreatAmmonia Waste
stockpile, etc. Combination of Air Stripping,Nitrification, Ion
Exchange. 17. Groundwater contaminated by Ethylene Dichloride and
Chloroform can betreated through in-situ bio remediation by using
certain types of Enzymesunder proper conversion parameters.This
In-Situ process is applicable to both fresh and brackish waters.50
to 80 percent biodegradation can be achieved by injecting Enzymes
inthe aquifer within 5 to 10weeks.Applicability:EDC (1.3 g/cc),
Chloroform (1.5 g/cc) , Chlorobenzene, Vinyl
Chloride,VOCs.Limitations:Permeability of the groundAquifer
MatrixPractical ExecutionThis In-Situ Bio remediation is
practically implemented by two industrialfacilities in Jubail to
reduce EDC and other chlorinated compounds from thegroundwater. 18.
Treatment of MTBE (Methyl Tertiary Butyl Ether )MTBE is broadly
used as Gasoline additiveand is one of the popular contaminant
ofthe groundwater.The solubility in water is as high as
4.3%comparing to Solubility of benzene andtoluene 0.18% and 0.05%
respectively.MTBE is very mobile and can spread tovery large
subsurface area very quickly.Groundwater contaminated with MTBE can
be treated by :In-Situ OxidationBioremediation (Enhanced by Oxygen
and Nutrients injection)Pump and Treat by Air Stripping &
Activated Carbon AdsorptionCombination of Catalytic Chemical
Oxidation with UV Presence. 19. Ammonia is one of the major
pollutants which contaminates groundwater.Ammonia contamination
could lead to Sea Water Pollution. Being Toxic toAquatic Organism,
Remediation of Ammonia is very important.US Department of Energy
has successfully conducted pilot studies on theInnovative Remedial
Techniques on an Aquifer near Moab, Utah, USA. Whichshows that
technologies are available for treating groundwater
contaminatedwith high levels of Ammonia to a safe level of 3
mg/LThese technologies includes:Pump and Treat by Ammonia
StrippingPump and Treat by Air Stripping and further
NitrificationPump and Treat by Ion ExchangeLimitation: Needs pH
Adjustments, 20. Royal Commission has always been concerned about
Public Health andEnvironment including Surface and Subsurface
groundwater.At Royal Commission Environmental Control
Department(RC-EPCD), we believe inPrevention from groundwater
contamination as the very first rule of remediation.Therefore,
Royal Commission Environmental Regulation (RCER) has made
itobligatory for all industries to stringently follow RCER
Groundwater Regulationsuch as:At least 3 Groundwater Monitoring
Wells in each industrial facility.Periodical Monitoring Groundwater
Quality.Periodical Reports to RC.Mandatory use of Impervious Liner
(1.5 mm thick HDPE liners) for : Tank foundations, Secondary
Containments(Dikes) and Storm Water PondStorage Tank Regulations:
Spill Control Devices , Leak Detection and Overfill System
Containments and Double Walls, Material of Construction 21.
Implementation of Leak Detection and Repair System toensure the
integrity of the pipelines and components.Separate Location for
Landfills: Inert Waste Non Hazardous Waste Hazardous Industrial
Wastes Sanitary Wastes.Landfill DesignDouble LinersGroundwater
Monitoring wells Near LandfillLeachate Collection SystemMonitoring
Groundwater Quality from 60 Monitoring Wells outsideindustrial
facilities in Jubail Industrial City.Reviewing Groundwater Quality
Reports submitted by IndividualIndustries from over 500 Wells in
the Jubail Industrial City.Checking Quality of Groundwater used for
Re-mineralization ofdrinking water which is supplied in Royal
Commission Area. 22. 1. Prevention from groundwater contamination
is the best Remedial Option.2. Mostly, groundwater contaminants are
of industrial origin.3. Royal Commission is closely monitoring the
quality of Groundwater through out the Jubail Industrial City and
also have implemented strict regulation for the prevention of
groundwater pollution.4. Environmental Awareness Programs Including
groundwater prevention should be Implemented for Community.5.
Innovative Technologies are available for the
groundwaterremediation, for several common contaminants including
EDCand Other Chlorinated Compounds, MTBE and Ammonia. 23.
Prevention Pays - Remedy Costsand The Prevention is in Our
Hands
