ENVIRONMENTAL MANAGEMENT
SYSTEM
EMS and ISO 14001
It is CPW's responsibility to make sure our operations both protect public health and the environment.
CPW manages actual and potential impacts on the environmental through the implementation of an Environmental Management System, or EMS. An EMS is a set of standards which provide a framework for how we identify and control environmental impacts, both positive and negative. EMS procedures govern everything from Standard Operating Procedures to record keeping to the development of detailed objectives and targets for improving environmental performance.
The EMS standards adopted by CPW are internationally recognized
environmental standards developed for global application by the International
Organization of Standardization based in Geneva, Switzerland. Though there are
many ISO standards, such as ISO 9000 for quality, ISO 14001 applies to
environmental issues. In 1999, CPW became the first public water or wastewater
utility in the United States to become ISO 14001 certified even though this is a
voluntary standard.
Environmental Aspects
The various impacts that CPW's operations and activities have on the environment are called "aspects". They include anything from the disposal of paper waste to the proper use of water treatment chemicals. While CPW manages many environmental aspects, some have a greater potential for substantially impacting the environment, and these are called "significant aspects." Significant aspects are not necessarily operations that pose a new or special risk - they may already be managed. However, CPW has identified these particular aspects for improvement potential, which is consistent with the EMS environmental policy of continual environmental improvement.
Click on an aspect below for a description.
General
Counter-terrorism
Sewer
System Infiltration and Inflow
Sewer
System Overflows
Wastewater
Tunnel Deterioration
Flow
Modeling
Corrosion
Control
Design
and Construction Projects
Hanahan Water Treatment Plant
Security
and Facility Protection
Sedimentation
Finished
Water Storage
Chemicals
Solids
Handling/Disposal
Emergency
Preparedness - Terrorism
Plum Island Wastewater Treatment
Plant
Grit
Removal and Disposal
Solids
Handling and Disposal
Scum
Removal
General
Counter-terrorism.
Any attack on one of CPW's water or wastewater treatment facilities would have
a negative impact on public health and the environment. In order to provide
counter-terrorism, CPW has worked closely with local and state law enforcement
and intelligence officials. Systematic risk assessments plans have been
developed that include increased levels of monitoring for potential
contaminants, improvements to security systems, increased numbers of security
personnel, and early-warning detection research and equipment.
Sewer System
Infiltration and Inflow.
Groundwater that leaches into CPW's wastewater collection system is called
infiltration and stormwater that finds its way into the collection system is
called "inflow". Both infiltration and inflow, when mixed with
sanitary wastewater, consume the hydraulic capacity of wastewater collection
mains, pump stations, and treatment plants. This can result in the need to
increase the size of these facilities to accommodate the hydraulic flow,
thereby resulting in increased capital expenditures. In the worst of case,
this additional infiltration and inflow could result in the overflow of
wastewater, diluted with rainwater, to be discharged into the environment. In
order to counter this negative impact, CPW has developed detailed standard
operating instructions for identifying and removing sources of infiltration
and inflow-such as illegal storm drain connections-from its wastewater
collection system. In addition, CPW has placed video cameras through the
collection system to identify main breaks, has smoke-tested mains, and has
repaired hundreds of broken wastewater mains.
Sewer
System Overflows.
An overflow of wastewater is a serious public health and environmental concern
because of disease-causing bacteria present in wastewater. Overflows can be
caused by several factors, including infiltration and inflow (see item 2,
above) and blockage caused by grease or debris. A significant rainfall
increases the potential for overflows, particularly in low-lying areas where
the inflow of rainwater may overwhelm system hydraulic capacity. CPW has
approved procedures in place to properly respond to overflow emergencies.
Standard Operating Procedures regarding operations and preventive maintenance
have also been implemented to reduce and/or eliminate occurrences.
Wastewater
Tunnel Deterioration.
The severe deterioration of the peninsula sewer tunnel, which carries
wastewater to the Plum Island treatment plant, is a serious threat to public
health and the environment. Divers inspecting the tunnel have discovered
debris build-up, collapse of the tunnel lining, and holes in the top of the
carrier pipe inside the tunnel. These circumstances could potentially block
the flow in the tunnel and cause an overflow of wastewater. CPW has already
replaced the most critical section of the tunnel-a mile-long section under the
Charleston Harbor, but recent discoveries of several cave-ins in the Ashley
River side of the tunnel have made replacement of the Ashley River tunnel even
more urgent. Engineers are working on plans to replace the Ashley River side
of the peninsula tunnel; meantime, divers are repairing damaged sections of
the tunnel by placing liner plates to help restore structural integrity to the
tunnel. In the event of a tunnel failure, a detailed Contingency Plan for
rapid deployment has been prepared.
Flow Modeling.
The South Carolina Department of Health and Environmental Control requires CPW
to maintain a minimum system pressure at every customer's tap under conditions
of maximum instantaneous demand as well as adequate flow to meet peak demand
for fire protection. Low pressure could not only reduce flow at the tap, but
also increases the potential of contaminated water backflowing into the
distribution system through sprinkler systems, garden hoses, etc. Chlorine is
used to disinfect water, and a trace amount is required to protect water from
contamination. To help ensure proper pressure and water quality throughout the
distribution system, CPW engineers use a complex computer program to model the
water flow and chlorine residuals in water mains. This model is also used
extensively to plan for future water main construction.
Corrosion Control.
Corrosion can cause deterioration and eventual failure of water lines. A line
break offers the potential for contamination of the distribution system
through backflow. Corrosion is caused by several factors, including the
installation of dissimilar metals and the presence of corrosive soils.
Installing protective coating around pipework and the use of zinc caps around
fittings can virtually eliminate corrosion, thereby extending the service life
of water mains. CPW has implemented a Corrosion Control Program with the
purpose of protecting all new water lines from corrosion and identifying areas
with corrosive soils so as to minimize future water main failures.
Design
and Construction Projects.
CPW routinely expands the water distribution and wastewater collection system
infrastructure and replaces outdated equipment and aging infrastructure. Such
projects include constructing a new wastewater tunnel on the Charleston
peninsula, replacement of sedimentation basins at the Hanahan Water Treatment
Plant, and extending water mains. Engineers in our design and construction
department are charged with ensuring projects comply with all regulatory
requirements and meet operating needs. By staying abreast of the latest
technology in the industry, CPW works to minimize energy consumption and
increase efficiency. CPW also has developed design manuals, guidelines for
construction, and Standard Operating Instructions for construction inspections
in order to guarantee the environmental and operating integrity of all new
projects.
Hanahan Water Treatment Plant
Security
and Facility Protection.
Protection of the water system against vandalism or terrorist attacks is
paramount for CPW. Such attacks could jeopardize critical water system
facilities and endanger the supply of drinking water and public health. Recent
security improvements have enhanced CPW's ability to detect, delay and respond
to attempted vandalism or terrorism that may involve water system facilities,
thereby offering greater protection for the water supply.
Sedimentation.
This step in the water treatment process treats raw water by allowing silt and
other solids to settle out in large sedimentation basins. Existing
sedimentation capacity is being increased to prepare for growth and rising
water demands. Some of the existing sedimentation basins and their equipment
are outdated and are being replaced with new, more reliable technology
designed to help meet increasingly stringent regulations.
Finished Water
Storage.
Finished water that is ready for distribution is stored in clearwells at the
water treatment plant. Adequate water storage is critical for meeting peak
demands and providing fire protection. CPW has plans to conduct a structural
evaluation of an aging clearwell to determine if the clearwell should be
upgraded or replaced.
Chemicals.
Many chemicals used for water treatment are stored in bulk storage tanks,
which are situated within spill containment structures. Inadequate chemical
storage tanks or spill containment structures could lead to environmental
contamination. CPW has plans to replace an outdated, undersized chemical
containment structure within the next two years.
Solids
Handling/Disposal.
Water treatment produces residual solids-silt, sand, and treatment
chemicals-most of which are collected in the sedimentation basins. These
treatment residuals must be thickened and ultimately disposed of in an
environmentally friendly manner. CPW is expanding its residuals processing
capacity in order to accommodate the aforementioned increase in sedimentation
basin capacity (see "Sedimentation," above). CPW currently disposes
of the water treatment residuals on a forested site, where they are allowed to
dry naturally, creating topsoil for trees. However, the existing land
application site will not have sufficient capacity to handle the increased
capacity of the residuals processing facility or the new sedimentation basins;
therefore, CPW is preparing to install a mechanical dewatering facility to
prepare excess residuals for landfill application.
Emergency
Preparedness - Terrorism.
In response to recent legislation regarding public water system protection
against potential terrorist activities, CPW is following through on
requirements to conduct a vulnerability assessment of its water system and to
update its emergency preparedness plans according to the assessment
recommendations. The emergency preparedness plans provide detailed plans to
prepare for and respond to an emergency. The updated emergency response plans,
coupled with other mitigating plans and infrastructure, offer CPW and
emergency response agencies detailed tools to offset potential emergency
events.
Plum Island Wastewater Treatment Plant
Grit Removal
and Disposal.
At the start of the wastewater treatment process wastewater moves slowly
through large tanks called grit chambers, allowing heavy particles such as
sand, gravel, seeds and coffee grounds to settle to the bottom by gravity.
These large materials must be removed prior to the next step in the treatment
process in order to maintain efficiency and protect equipment. The removed
grit is then dewatered and disposed of in a secure landfill. CPW has standard
operating procedures to ensure the environmentally efficient removal and
disposal of this material.
Solids
Handling and Disposal.
Microorganisms that naturally live in wastewater are used to digest organic
materials and other contaminants during the treatment process called
"Activated Sludge." These microorganisms use the organic material as
food and clean the water as they grow and multiply. After cleaning the water,
the excess microorganisms are collected, thickened, and dewatered using large
belt presses which squeeze out the excess water. What is left is a damp
dirt-like material that is transported by trucks to a landfill for disposal.
This sludge also contains sand and other particles that settle out of
wastewater before the activated sludge treatment process. Because a spill of
this material could present a potential public health concern, CPW has strict
Standard Operating Instructions in place for transporting sludge. Sludge
transporting trucks are inspected before each trip and undergo routine
maintenance and safety checks along with annual inspections required by the
state Department of Transportation. All CPW truck drivers are required to have
appropriate CDL licenses along with safety and background checks.
Improvement projects are underway at both the Plum Island and Daniel Island wastewater treatment plants for solids handling. New advanced technology rotary presses will be installed to handle solids disposal at the Daniel Island plant. The Plum Island facility is installing an interim high-speed centrifuge to dewater the solids and CPW is considering utilizing rotary presses for long-term disposal.
Scum Removal.
Domestic wastewater contains a variety of fats, oils and grease from home and
commercial food preparation. During the treatment process, this
material-commonly referred to as "scum"-floats to the surface and is
removed for proper disposal. Handling this material properly helps control
odors and prevents the material from interfering with subsequent treatment
processes. In addition to Standard Operating Procedures, Plum Island recently
replaced and upgraded the 20-year-old scum handling equipment with an
automated process, which has resulted in increased efficiency and odor
reduction.
For more information about CPW's Environmental Management System or Significant Aspects, please contact the Managers Office at (843) 727-6856 or by e-mail at haganjl@charlestoncpw.com.