Data Source: Soil and Groundwater Pollution Remediation Web of Taiwan
http://sgw.epa.gov.tw/public/En/index.htm
Remediation Sites→7.1 Introduction of Various Pollution in Taiwan→3
Large Storage Tank Pollution
The gas stations that opened more than 10 years and storage tanks that were
built many years ago may have leaking problems due to aged pipeline or tank without
proper maintenance, stratum level change, and improper operation. Broken tank and
pipeline will be undermined and cause a stored chemical leak into the soil and
groundwater, therefore gas stations and underground storage tanks are potential
pollution sources. To ensure the gas station underground storage tank operation is
properly running and prevents the occurrence of the soil and groundwater pollution,
the EPA carried out the Gas Station and Underground Storage Tank Pollution
Potential Survey from the years 2001 to 2003. The survey data including existing
condition and pollution potential assessment are completed and hopefully this will
help us to discover the problem and prevent the groundwater pollution by oil and other
pollutants.
To understand the existing condition for the gas station that has opened more
than 10 years and storage tanks that were built a long time ago, EPA carried out Soil
and Groundwater Pollution Potential Survey in the years 2002 and 2003 to gather the
information and transfer the data into a specific database. EPA also investigates site
reported by the public as pollution site in accordance of Article 11, paragraph 1 of the
Remediation Act. If the pollutant concentration is exceeding the control standard, then
the site is being listed as a control site and necessary control measures are taken to
avoid the expansion of the pollution scope.
Possible leaking point at storage tank
Daily Operation Area in the Storage Tank
Storage Tank Dike
The Bottom of the Storage Tank and its
Peripherals
Entry and Exist for the Storage Tank Pipeline
Large Storage Tank Survey
According to the Potential Groundwater Pollution Source Survey Project statistic
data, The most tanks are located in Kaohsiung City, and thre are 867 tanks. The next
region that deserves attention is Kaohsiung County with 836 tanks, and Yunlin County
with 524 tanks. In Lin-Yuan Industrial District, there are 530 storage tanks, 518
storage tanks in Formosa Industrial District and 331 storage tanks in Kaohsiung
petroleum refinery. Storage tanks with capacity greater than 100 kiloliter number 3351
tanks. The local government surveyed the storage tank pollution site and the number
of storage tanks. The year 2002 has site survey completed for 1402 tanks in 21 sites
while year 2003 has survey completed for 2171 tanks in 172 sites. Totally there were
3573 tanks located in 193 sites completed with the potential pollution source survey.
Surveying is classified into 3 stages:
First stage: Analyze the soil gas sample.
Second stage: Investigate the soil and groundwater in the site.
Third stage: Investigate the soil and groundwater pollution at the target tank.
The surveyed items classified by the soil and groundwater are:
Soil surveyed item:
Survey the 21 organic compounds listed in the soil pollution control standard,
including Benzene, Carbon tetrachloride, Chloroform, 1,2-Dichloroethane,
cis-1,2-Dichloroethylene, trans-1,2-Dichloroethylene, 1,2-Dichloropropane,
1,2-Dichlorobenzene, 1,3-Dichlorobenzene, 3,3’-Dichlorobenzidine,
Ethylbenzene, Hexachlorobenzene, Pentachlorophenol, Tetrachloroethylene,
Toluene, Total petroleum hydrocarbons (TPH), Trichloroethylene,
2,4,5-Trichlorophenol, 2,4,6-Trichlorophenol, Vinyl chloride, and Xylenes.
Groundwater survey items:
There are 17 one ring, multiple rings aromatic hydrocarbon compound and
chlorine-carbon-hydrogen compounds meeting the groundwater pollution control
standard including：Benzene, Toluene, Naphthalene, Carbon tetrachloride,
Chlorobenzene, Chloroform, Chloromethane, 1,4-Dichlorobenzene,
1,1-Dichloroethane, 1,2-Dichloroethane, 1,1-Dichloroethylene,
cis-1,2-Dichloroethylene, trans-1,2-Dichloroethylene, phenols,
Tetrachloroethylene, Trichloroethylene, Vinyl chloride, methyl tertiary-butyl ether
(MTBE) and oxygen reduction potential (ORP).
Through large storage tank pollution potential investigation projects, high
potential tanks are selected. Individual reported pollution sites are enlisted as control
sites if the pollutant concentration reaches pollution control standard. The most
commonly found pollutant in soil from storage tanks is Total petroleum hydrocarbons
(TPH), while the most commonly found in groundwater is Benzene. Pollutant
presented is related to the tank content and production process.
Survey of the Storage Tank
Select Sampling Point (Industrial hygienist was
presented)
GPS Sampling
RC/PC Aperture Broken
Construct Temporary Monitoring Well (Well is 2
inches deep)
Inject Sampling Tube
Disposable Mini-bailer Sampling
Groundwater Level Measurement (measured by Temporary well are back-filled by gravels and
the water level)
cements.
Large Storage Tank Pollution Control
Major scope of the large storage tank pollution control are the followings:
I.Control pollutant flow and affected range: Adopt groundwater well monitoring
and analyze the data.
II. Floating oil clearing by pumping: factitious pumping, Dual Pump pumping, and
biowash.
III. Leaking point survey: Adopt ultraviolet ray scanning, liquid pressure testing,
sound frequency testing, pollutant tracer, and passive soil gas survey.
IV. Soil and groundwater pollution control technology: Adopt Pump & Treat,
Enhanced Bioremediation, Natural Attenuation, Air Sparging, Passive/Reactive
Treatment Walls, and Chemical Oxidation.
V. Continue environment monitoring.
Photo Sources: Taiwan EPA and Each Local Environmental Protection Bureau