Industrial Stormwater Sector Z: Leather Tanning and Finishing Facilities


INDUSTRIAL   STORMWATER
FACT  SHEET  SERIES
                                                   Sector Z; Leather Tanning and
                                                              Finishing Facilities
            U.S. EPA Office of Water
            EPA-833-F-06-041
            December 2006
  What is the NPDES stormwater permitting program for industrial
  activity?
  Activities, such as material handling and storage, equipment maintenance and cleaning, industrial
  processing or other operations that occur at industrial facilities are often exposed to stormwater. The
  runoff from these areas may discharge pollutants directly into nearby waterbodies or indirectly via
  storm sewer systems, thereby degrading water quality.

  In 1990, the U.S. Environmental Protection Agency (EPA) developed permitting regulations under the
  National Pollutant Discharge Elimination System (NPDES) to control stormwater discharges associated
  with eleven categories of industrial activity. As a result, NPDES permitting authorities, which may be
  either EPA or a state environmental agency, issue stormwater permits to control runoff from these
  industrial facilities.

  What types of industrial facilities are required to obtain permit
  coverage?
  This fact sheet specifically discusses stormwater discharges from leather tanning and finishing facilities
  as defined by Standard Industrial Classification (SIC) Major Group 31. This includes both leather
  tanning facilities and facilities which make fertilizer solely from leather scraps and leather dust.
  Stormwater discharges from access roads and rail lines used or traveled by carriers of raw materials,
  manufactured products, waste materials, or by-products created by the facility are also required to be
  covered under an industrial stormwater permit.

  What does an industrial stormwater permit require?
  Common requirements for coverage under an industrial stormwater permit include development of a
  written stormwater pollution prevention plan (SWPPP), implementation of control measures, and sub-
  mittal of a request for permit coverage, usually referred to as the Notice of Intent or NOI. The SWPPP
  is a written assessment of potential sources of pollutants in stormwater runoff and control measures
  that will be implemented at your facility to minimize the discharge of these pollutants in runoff from
  the site. These control measures include site-specific best management practices (BMPs), maintenance
  plans, inspections, employee training, and reporting. The procedures detailed in the SWPPP must be
  implemented by the facility and updated as necessary, with a copy of the SWPPP kept on-site. The indus-
  trial stormwater  permit also requires collection of visual, analytical, and/or compliance monitoring data
  to determine the effectiveness of implemented BMPs. For more information on EPA's industrial storm-
  water permit and links to State stormwater permits,  go to www.epa.gov/npdes/stormwater and click
  on "Industrial Activity."

  What pollutants are associated with my facilities activities?
  Pollutants conveyed in stormwater discharges from leather tanning and finishing facilities will vary.
  There are a number of factors that influence to what extent industrial activities and significant
  materials can affect water quality.
    4 Geographic location
    4 Topography

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INDUSTRIAL STORMWATER  FACT SHEET SERIES
Sector Z: Leather Tanning and Finishing Facilities
     4  Hydrogeology
     4  Extent of impervious surfaces (e.g.,, concrete or asphalt)
     4  Type of ground cover (e.g., vegetation, crushed stone, or dirt)
     4  Outdoor activities (e.g., material storage, loading/unloading, vehicle maintenance)
     4  Size of the operation
     4  Type, duration, and intensity of precipitation events
  The activities, pollutant sources, and pollutants detailed in Table 1 are commonly found at leather
  tanning and finishing facilities.

  Table 1.  Common Activities, Pollutant Sources, and Associated Pollutants at Leather Tanning and
  Finishing Facilities
Activity
Outdoor storage of
fresh and brine cured
hides
Beamhouse processes
(trimming, soak
and wash, fleshing,
unhairing)
lanyards (bating,
pickling, tanning,
wringing, splitting,
shaving)
Retan and wet
finishing (retanning,
bleaching and
coloring, fatliquoring,
buffing)
Dry finishing
(application of
pigment to leather
surface with water-
based or solvent based
finishes)
Receiving and
unloading areas
Improper connections
to storm sewer
Outdoor bulk chemical
storage
Outdoor storage of
coal
Pollutant Source
Fresh and brine cured hides
Chemical storage (drums or bags)
Empty containers of lime, depilatory
chemicals
Trim scraps, hair
Empty chemical containers
"Blue" hides, splits, trimmings, shavings
Empty chemical containers
Leather dust containing chromium
Emissions from spray booths and spent
solvents
Hides
Chemical supplies
Leaking trucks
Accidental spills
Floor drains, process wastewater, cleaning
and washdown of process equipment and
process areas
Above ground tanks
Coal piles
Pollutant
Salt, organic materials (manure), biochemical
oxygen demand, total suspended solids (TSS).
Depilatory chemicals.
Calcium hydroxide, sodium sulfhydrate, or
sodium sulfide.
BOD, COD, TSS, high pH, TKN
Trivalent chromium, vegetable tannins, enzymes,
pickling acids (sulfuric acid), alum, syntans,
chemical deliming agents, glutaraldehyde, heavy
oils.
Trivalent chromium, leather fiber and dust,
suspended solids, BOD, TSS, dissolved solids.
Chromium tanning agents, vegetable extract,
dyes, pigments, animal or vegetable based oils,
synthetic oils made from modified mineral based
oils, sulfonated oils, spent dyes
Leather fiber, trivalent chromium, TSS, tannins
Pigments, solvents-acetone, pylene, glycol ether
Trivalent chromium, salt.
Depilatory chemicals, trivalent chromium,
vegetable tannins, enzymes, pickling acids
(sulfuric acid), alum, syntans, chemical deliming
agents, glutaraldehyde, heavy oils, dyes,
pigments, animal or vegetable based oils,
synthetic oils, solvents and biocides.
Oil and grease and waste materials.
Chemicals listed for supplies above.
Dependent on operations.
Sulfuric acid, ferric chloride, finishing solvents
(mineral spirits), hydrated lime, surfactant.
Oil & grease, TSS, copper, nickel, zinc.
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INDUSTRIAL STORMWATER FACT SHEET SERIES
Sector Z: Leather Tanning and Finishing Facilities
  Table 1. Common Activities, Pollutant Sources, and Associated Pollutants at Leather Tanning and
  Finishing Facilities (continued)
Activity
Waste management
Vehicle and equipment
maintenance
Pollutant Source
Hoppers
Dumpsters
Sludge (wastewater treatment sludge stored
in containers to diminish stormwater contact,
awaiting offsite disposal)
Parts cleaning
Waste disposal of oily rags, oil filters, air
filters, batteries
Fluid replacement including hydraulic fluid,
brake fluid, oil, transmission fluid, coolants,
and lubricants
Pollutant
Leather dust, scraps.
Empty bags & chemical containers.
Lime, pieces of leather, hair, protein-like
substances, floor sweepings, trivalent chromium,
biochemical oxygen demand.
Solvents, oil, heavy metals, acid/alkaline wastes
Oil, heavy metals, solvents, acids
Oil and grease, arsenic, lead, cadmium,
chromium, chemical oxygen demand (COD), and
benzene
  What BMPs can be used to minimize contact between stormwater
  and potential pollutants at my facility?
  A variety of BMP options may be applicable to eliminate or minimize the presence of pollutants in
  stormwater discharges from leather tanning and finishing facilities. You will likely need to implement
  a combination or suite of BMPs to address stormwater runoff at your facility. Your first consideration
  should be for pollution prevention BMPs, which are designed to prevent or minimize pollutants
  from entering stormwater runoff and/or reduce the volume of stormwater requiring management.
  Prevention BMPs can include regular cleanup, collection and containment of debris in storage areas,
  and other housekeeping practices, spill control, and employee training. It  may also be necessary to
  implement treatment BMPs, which are engineered structures intended to  treat stormwater runoff
  and/or mitigate the effects of increased stormwater runoff peak rate, volume, and velocity. Treatment
  BMPs are generally more expensive to install and maintain and  include oil-water separators, wet
  ponds, and proprietary filter devices.

  BMPs must be selected and implemented to address the following:

  Good Housekeeping Practices
  Good housekeeping  is a practical, cost-effective way to maintain  a clean and orderly facility to prevent
  potential pollution sources from coming into contact with stormwater. It includes establishing protocols
  to reduce the possibility of mishandling materials or equipment and training employees in good
  housekeeping techniques. Common areas where good housekeeping practices should be followed
  include trash containers and adjacent areas, material storage areas, vehicle  and equipment maintenance
  areas, and loading docks. Good housekeeping practices must include a schedule for regular pickup
  and disposal of garbage and waste materials and routine inspections of drums, tanks, and containers
  for leaks and  structural conditions. Practices also include containing and covering garbage, waste
  materials, and debris. Involving employees in routine monitoring of housekeeping practices has proven
  to be an effective means of ensuring the continued implementation of these measures.

  Specific good housekeeping practices for leather tanning and finishing facilities include:
     4  Labeling storage containers of all materials  (e.g., specific chemicals, hazardous materials, spent
        solvents, waste materials).
     4  Preventive inspection/maintenance programs or other appropriate  preventive measures in
        buffing and shaving areas.
     4  Cleaning all contaminated equipment thoroughly before storing outdoors
     4  Inspection/maintenance programs for leaking containers or spills
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INDUSTRIAL STORMWATER FACT SHEET SERIES
Sector Z: Leather Tanning and Finishing Facilities
Minimizing Exposure
Where feasible, minimizing exposure of potential pollutant sources to precipitation is an important
control option. Minimizing exposure prevents pollutants, including debris, from coming into contact
with precipitation and can reduce the need for BMPs to treat contaminated stormwater runoff. It can
also prevent debris from being picked up by stormwater and carried into drains and surface waters.
Examples of BMPs for exposure minimization include covering materials or activities with temporary
structures (e.g., tarps) when wet weather is expected or moving materials or activities to existing
or new permanent structures (e.g., buildings, silos, sheds). Even the simple practice of keeping a
dumpster lid closed can be a very effective pollution prevention measure.

Specific exposure minimization practices for leather tanning and finishing facilities include:
4 Storing pallets/bales of raw, semi-processed or finished tannery byproducts (e.g., splits,
trimmings, shavings, etc.) indoors or protecting by polyethylene wrapping, tarpaulins, roofed
storage, etc.
4 Covering chemical supplies, equipment, and waste piles stored outdoors
4 Placing stored materials on an impermeable surface, and enclosing or putting berms (or
equivalent measures) around the area to prevent stormwater run-on/runoff.
4 Using dust collection enclosures in buffing and shaving areas
4 Covering dumpsters
4 Moving waste management activities indoors

Erosion and Sediment Control
BMPs must be selected and implemented to limit erosion on areas of your site that, due to
topography, activities, soils, cover, materials, or other factors are likely to experience erosion. Erosion
control BMPs such as seeding, mulching, and sodding prevent soil from becoming dislodged and
should be considered first. Sediment control BMPs such as silt fences, sediment ponds, and stabilized
entrances trap sediment after it has eroded. Sediment control BMPs should be used to back-up
erosion control BMPs.

Management of Runoff
Your SWPPP must contain a narrative evaluation of the appropriateness of stormwater management
practices that divert, infiltrate, reuse, or otherwise manage stormwater runoff so as to reduce the
discharge of pollutants. Appropriate measures are highly site-specific, but may include, among others,
vegetative swales, collection and reuse of stormwater, inlet controls, snow management, infiltration
devices, and wet retention measures.

Specific runoff management practices for by leather tanning and finishing facilities include diverting
drainage from receiving, unloading, and material and waste storage areas to the process sewer or
grading and berming/curbing area to prevent runoff of stormwater.

A combination of preventive and treatment BMPs will yield the most effective stormwater
management for minimizing the offsite discharge of pollutants via stormwater runoff. Though not
specifically outlined in this fact sheet, BMPs must also address preventive maintenance records or
logbooks, regular facility inspections, spill prevention and response, and employee training.

All BMPs require regular maintenance to function as intended. Some management measures have
simple maintenance requirements, others are quite involved. You must regularly inspect all BMPs to
ensure they are operating properly, including during runoff events. As soon as a problem is found,
action to resolve it should be initiated immediately.

Implement BMPs, such as those listed below in Table 2 for the control of pollutants at leather tanning
and finishing facilities, to minimize and prevent the discharge of pollutants in stormwater. Identifying
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INDUSTRIAL STORMWATER FACT SHEET SERIES
Sector Z: Leather Tanning and Finishing Facilities
weaknesses in current facility practices will aid the permittee in determining appropriate BMPs that
will achieve a reduction in pollutant loadings. BMPs listed in Table 2 are broadly applicable to leather
tanning and finishing facilities; however, this is not a complete list and you are recommended to
consult with regulatory agencies or a stormwater engineer/consultant to identify appropriate BMPs
for your facility.
Table 2. BMPs for Potential Pollutant Sources at Leather Tanning and Finishing Facilities
Pollutant Source
BMPs
Temporary outdoor
storage of fresh or
brine cured hides
Q Store hides indoors if possible.
FJ Cover the hides with a roof or temporary covering (e.g., polyethylene, tarpaulin etc.).
Q Locate storage areas away from high traffic areas and surface waters.
Q Minimize stormwater run-on by enclosing the area or use berms, curbs, grassed swales or
other diversion measures to ensure that stormwater runoff from other parts of the facility
does not flow over the area.
Q Inspect area regularly for proper implementation of good housekeeping and control
measures.
FJ Train employees on waste control and disposal procedures.
Beamhouse and
tanyard operations
FJ Store chemical drums & bags and empty lime & depilatory chemical containers indoors if
possible.
FJ Cover chemical drums & bags, empty lime & depilatory chemical containers and leather
scraps with roof or temporary covering (e.g., tarpaulins, polyethylene) and store on elevated
impermeable surface.
FJ Install curbing, containment dikes around chemical storage, empty lime & depilatory chemical
containers and leather scrap storage area.
FJ Avoid use of hides treated with insecticides and fungicides. Use salts or chilling methods
instead.
Q Avoid toxic and less biodegradable antiseptics and biocides. Especially avoid those containing
arsenic, mercury, lindane, and pentachlorophenol or other chlorinated substances.
Q Minimize the use of chrome. Use trivalent chrome rather than hexavalent. Recover and recycle
chrome to the extent possible.
FJ Reduce quantities of salt used for preservation.
FJ Maintain an inventory of fluids to identify leakage and properly dispose of chemicals that are
no longer in use.
Q Clean up leaks and spills immediately.
Q Use drip pans for leaking equipment.
FJ All paved areas should be swept regularly, eliminate unnecessary flushing with water and
label chemical drums and containers.
FJ Inspect area regularly for leaking drums, broken bags, proper implementation of good
housekeeping and control measures, (broken cracked dikes), material inventory, material
storage and operation & maintenance.
FJ Train employees on good housekeeping, proper handling of chemicals.
Retan and wet finish
FJ Reduce dust through enclosure and covering.
Q Use nonorganic solvents for dyeing and refinishing.
FJ Implement and maintain dust collectors (vacuum, bag & cyclone) and filter systems.
FJ Regularly sweep paved areas, eliminate unnecessary flushing with water and label chemical
drums and containers.
Q Train employees on good housekeeping and proper handling of chemicals.
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Buffing and shaving
areas
Receiving and
shipping

Storage areas for raw,
semiprocessed, or
finished tannery by-
products

BMPs
a
a
a
a
a
a
a
a
a
a

a
a
a
a

a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
Use effective spray equipment that delivers more dye to the target and less overspray
Have absorbent and other cleanup items readily available for immediate cleanup of spills.
Store dyes and solvents away from traffic areas to avoid spills.
Recycle paint, paint thinner, and solvents.
Establish and implement effective inventory control to reduce waste, including tracking date
received and expiration dates.
Store dyes, paint, solvents, and rags in covered containers to prevent evaporation to the
atmosphere.
Use solvents with low volatility and coatings with low VOC content; use high transfer
efficiency coating techniques.
Inspect spray booths area regularly to ensure BMPs are implemented.
Train employees on proper spraying techniques and disposal of spent solvents.
Install dust collection enclosures, preventative inspection/maintenance programs.

Confine loading/unloading activities to designated areas outside drainage pathways and away
from surface waters.
Inspect containers for leaks or damage prior to loading/unloading.
Avoid loading/unloading materials in the rain or provide cover or other protection for loading
docks.
Provide diversion berms, dikes or grassed swales around the perimeter of the area to limit
run-on.
Cover loading and unloading areas and perform these activities on an impervious pad to
enable easy collection of spilled materials.
Slope the impervious concrete floor or pad to collect spills and leaks and convey them to
proper containment and treatment.
Provide overhangs or door skirts to enclose trailer ends at truck loading/unloading docks.
For rail transfer, a drip pan shall be installed within the rails to collect spillage from the tank.
Where liquid or powdered materials are transferred in bulk to/from truck or rail cars, ensure
hose connection points at storage containers are inside containment areas, or drip pans are
used in areas where spillage may occur which are not in a containment area.
Enclose material handling systems.
Cover materials entering and leaving areas.
Regularly sweep area to minimize debris on the ground.
Provide dust control if necessary. When controlling dust, sweep and/or apply water or
materials that will not impact surface or ground water.
Develop and implement spill prevention, containment, and countermeasure (SPCC) plans.
Train employees in spill prevention, control, cleanup, and proper materials management
techniques.
Pallets and/or bales of raw, semiprocessed, or finished byproducts should be stored indoors or
protected by polyethylene wrapping, tarpaulins, roofed storage area, or other suitable means.
Confine activities to designated areas outside drainage pathways and away from surface
waters.
Provide diversion berms, dikes or grassed swales around the perimeter of the area to limit
run-on and runoff.
Place materials on an impermeable surface.
Minimize storage of flesh trimmings and organic materials.

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INDUSTRIAL STORMWATER FACT SHEET SERIES
Sector Z: Leather Tanning and Finishing Facilities
Table 2. BMPs for Potential Pollutant Sources at Leather Tanning and Finishing Facilities (continued)
Pollutant Source
BMPs
Material storage areas
FJ Store materials indoors.
FJ Install berms or dikes around storage area.
Q Label storage units of all materials.
FJ Maintain containers and units in good condition.
Outdoor storage
of contaminated
equipment
Protect equipment by suitable cover.
Divert drainage to the process sewer.
Clean equipment thoroughly prior to storage.
Liquid storage in
above ground tanks
Q If area is uncovered, connect sump outlet to sanitary sewer (if possible) or an oil/water
separator, catch basin filter, etc. If connecting to a sanitary sewer check with the system
operator to ensure that the discharge is acceptable. If implementing separator or filter
technologies ensure that regular inspections and maintenance procedures are in place.
Q Provide secondary containment, such as dikes, with a height sufficient to contain a spill
(the greater of 10 percent of the total enclosed tank volume or 110 percent of the volume
contained in the largest tank).
Q If containment structures have drains, ensure that the drains have valves, and that valves
are maintained in the closed position. Institute protocols for checking/testing stormwater in
containment areas prior to discharge.
Q Use double-walled tanks with overflow protection.
FJ Keep liquid transfer nozzles/hoses in secondary containment area.
Q Clearly tag valves to avoid human error.
Q Install overflow protection devices on tank systems to warn operator or to automatically shut
down transfer pumps when tanks reach full capacity.
FJ Inspection of tank foundations, connections, coatings, valves and piping systems.
FJ Comply with existing spill prevention, cleanup and countermeasure plans (SPCC plan) and
State and Federal laws.
Q Perform integrity testing regularly by qualified professionals.
Q Train employees in spill prevention and control.
Improper connections
to storm sewers
Plug all floor drains connected to sanitary or storm sewers.
Perform smoke or dye testing to determine if interconnections exist between sanitary water
system and storm sewer system.
FJ

FJ Update facility schematics to accurately reflect all plumbing connections.
Install a safeguard against washwaters from processing areas entering the storm sewer unless
permitted.
Train employees on proper disposal practices for all materials.
Coal piles
FJ Confine storage to areas outside of drainage pathways and away from surface waters.
FJ Divert stormwater around storage areas with vegetated swales, and/or berms.
Q Practice good housekeeping measures such as frequent removal of dust and debris. Cleanup
methods may include mobile sweepers, scrapers, or scoops.
Q Use properly designed basins for collection, containment, and recycling of pile spraying
materials.
Use control measures such as berms, silt fences or waddles to control sediment from leaving
storage area.
FJ

FJ Train employees in good housekeeping measures.
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INDUSTRIAL STORMWATER FACT SHEET SERIES
Sector Z: Leather Tanning and Finishing Facilities
Table 2. BMPs for Potential Pollutant Sources at Leather Tanning and Finishing Facilities (continued)
Pollutant Source
BMPs
Waste management
FJ Conduct waste reduction assessment - develop guidelines for the elimination of waste
generation emissions.
FJ Minimize solids waste by recovery and reuse of hide trimmings and other wastes for
manufacturing glue, gelatin, tallow, etc.
FJ Institute industrial waste source reduction and recycling.
FJ Move waste management activities indoors (after safety concerns are addressed) and cover
waste piles, dumpsters, hoppers, place on impermeable elevated surfaces.
Q Provide diversion berms, dikes or grassed swales around the perimeter of the area to limit
run-on.
Q Cover trucks and inspect for leaking wastes.
Q Inspect waste management areas for leaking containers, spills, damaged containers,
uncovered waste piles, dumpsters, hoppers.
FJ Develop and maintain proper erosion control or site stabilization measures.
FJ Train employees on waste management and disposal practices for all materials.
Vehicle and
equipment
maintenance
Good Housekeeping
Q Eliminate floor drains that are connected to the storm or sanitary sewer; if necessary, install a
sump that is pumped regularly. Collected wastes should be properly treated or disposed of by
a licensed waste disposal company.
Q Do all cleaning at a centralized station so the solvents stay in one area.
Q If parts are dipped in liquid, remove them slowly to avoid spills.
FJ Use drip pans, drain boards, and drying racks to direct drips back into a fluid holding tank for
reuse.
FJ Drain all parts of fluids prior to disposal. Oil filters can be crushed and recycled.
Q Promptly transfer used fluids to the proper container; do not leave full drip pans or other
open containers around the shop. Empty and clean drip pans and containers.
Q Clean up leaks, drips, and other spills without using large amounts of water. Use absorbents
for dry cleanup whenever possible.
Q Prohibit the practice of hosing down an area where the practice would result in the discharge
of pollutants to a stormwater system.
Q Do not pour liquid waste into floor drains, sinks, outdoor storm drain inlets, or other storm
drains or sewer connections.
Q Maintain an organized inventory of materials.
FJ Eliminate or reduce the number and amount of hazardous materials and waste by
substituting nonhazardous or less hazardous materials.
FJ Label and track the recycling of waste material (e.g., used oil, spent solvents, batteries).
Q Store batteries and other significant materials inside.
Q Dispose of greasy rags, oil filters, air filters, batteries, spent coolant, and degreasers in
compliance with RCRA regulations.
Minimizing Exposure
FJ Perform all cleaning operations indoors or under covering when possible. Conduct the
cleaning operations in an area with a concrete floor with no floor drainage other than to
sanitary sewers or treatment facilities.
FJ If operations are uncovered, perform them on concrete pad that is impervious and contained.
FJ Park vehicles and equipment indoors or under a roof whenever possible and maintain proper
control of oil leaks/spills.
FJ Check vehicles closely for leaks and use pans to collect fluid when leaks occur.
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Q Use berms, curbs, grassed swales or similar means to ensure that stormwater runoff from
other parts of the facility does not flow over the maintenance area.

FJ Collect the stormwater runoff from the cleaning area and provide treatment or recycling.

FJ Discharge vehicle wash or rinse water to the sanitary sewer (if allowed by sewer authority),
wastewater treatment, a land application site, or recycled onsite. DO NOT discharge
washwater to a storm drain or to surface water.

Inspections and Training

Q Inspect the maintenance area regularly to ensure BMPs are implemented.

Q Train employees on waste control and disposal procedures.
What if activities and materials at my facility are not exposed to
precipitation ?
The industrial stormwater program requires permit coverage for a number of specified types of industrial
activities. However, when a facility is able to prevent the exposure of ALL relevant activities and materials
to precipitation, it may be eligible to claim no exposure and qualify for a waiver from permit coverage.

If you are regulated under the industrial permitting program, you must either obtain permit coverage or
submit a no exposure certification form, if available. Check with your permitting authority for additional
information as not every permitting authority program provides no exposure exemptions.

Where do I get more information?
For additional information on the industrial stormwater program see
www.epa.gov/npdes/stormwater/msgp.

A list of names and telephone numbers for each EPA Region or state NPDES permitting authority can
be found at www.epa.gov/npdes/stormwatercontacts.

References
Information contained in this Fact Sheet was compiled from EPA's past and current Multi-Sector General
Permits and from the following sources:

4 U.S. EPA, Office of Science and Technology. 1999. Preliminary Data Summary of Urban Stormwater
Best Management Practices. EPA-821-R-99-012.
www.epa.gov/OST/stormwater/

4 U.S. EPA, Office of Wastewater Management. NPDES Stormwater Multi-Sector General Permit for
Industrial Activities (MSGP).
www.epa.gov/npdes/stormwater/msgp

4 World Bank Group.1998. Pollution Prevention and Abatement Handbook.
www-wds.worldbank.org/servlet/WDS_IBank_Servlet?pcont=details&eid=000094946_99040905052283
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