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The NPDES system
     It stands for a mouthful: National Pollution Discharge Elimination System. It's the permit-based program designed to regulate the discharge of pollutants into US waters. Started in 1972, it is one of the principal operating mechanisms of the federal Clean Water Act and the foundation of state and federal programs to prevent and control water pollution.
     Section 402 of the Clean Water Act prohibits the discharge of any pollutant from a pipe, drain or other "point source" into navigable waters of the United States unless the discharger has a NPDES permit. Anyone discharging pollutants into the nation's waters without a permit or in violation of a valid permit is breaking the law. Of course, the corollary is also true: It is perfectly legal to discharge pollutants in compliance with a valid permit.

NPDES permits in North Carolina
     Though this is a program required by federal law, scientists and engineers with the state Division of Water Quality write NPDES permits in North Carolina. The division also enforces NPDES permits and provides technical assistance to permit holders.

Kinds of permits 
     There are about 1,600 active NPDES permits in North Carolina. They come in two forms: general and individual. Individual permits apply to a single facility, such as a sewage treatment plant, pulp mill, or shipyard. General permits apply statewide to a category of similar activities. For example, general permits cover sand dredging and seafood packaging.
     Plants that treat domestic sewage make up, by far, the largest category of permits. These plants collect and treat wastewater from industrial and residential users. The content of the wastewater may differ dramatically depending on whether the plant accepts waste from industries or merely from residences. They discharge the waste directly into the water or by applying treated waste and sludge onto agricultural or rural land.
     Those that dump their sewage into the water are considered "direct dischargers" and their permits always start with NC. Plants that apply treated sewage onto the land are considered "non-dischargers." Though they aren't regulated under the NPDES system, such plant also require permits, which start with WQ, and must meet similar discharge limits.

Types of Active NPDES Permits in NC

     Most of the domestic sewage plants that have NPDES or non-discharge permits in North Carolina are privately owned. Towns, cities or counties own the others.
     Industries make up the bulk of the remainder of permit holders. The manufacturing process for most products yields a wide variety of by-products that must be disposed of in some fashion. Industries typically obtain NPDES permits to dump these pollutants into the water. The alternative method is to send the waste to a public or private domestic sewage plant. Such plants, though, aren't designed to treat heavy metals such as zinc or copper and chemicals such as cyanide. They usually require the industries to remove those pollutants before sending the waste to the plant.

How NPDES permits protect water 
     An NPDES permit will generally specify what the state considers acceptable levels of pollutants in a discharge – for example, a certain level of bacteria. The permit holder may choose which technologies to use to achieve that level. Some permits, however, do contain certain generic "best management practices," such as installing a screen over the pipe to keep debris out of the waterway.
     Most NPDES permits are renewed every five years. At each renewal, the permit is supposed to be tightened – ratcheted down – to decrease the pollution being discharged. The goal is to eliminate pollution. We're not remotely close to meeting that goal.

Types of pollutants
     NPDES permits generally regulate three categories of pollutants: conventional, toxics, and non-conventional.

• Conventional Pollutants: These are specifically defined in the federal regulations and are representative of basic sewage components. They are biochemical oxygen demand (BOD), total suspended solids (TSS), fecal coliform bacteria, oil and grease, and pH. These are relatively easy to test and are used for the basic limits in most permits. For example, all sewage permits should have limits for all of these, except oil and grease. For industrial permits or sewage plants that need more advanced treatment because of the complexity of the waste they handle or the size or sensitivity of the receiving stream, additional pollutants or parameters are put in the permit.
• Toxic Pollutants: These are particularly harmful to people and animals. In high concentrations they can kill. Even in lower doses, these pollutants can trigger disease, behavioral abnormalities, genetic mutations, physiological malfunctions, or physical deformities in organisms that ingest or absorb them. The quantities and length of exposure necessary to cause these effects can vary widely. Toxic pollutants are grouped into two categories: organics and metals. Organics include such things as pesticides, solvents, PCBs, and dioxins. Common metals include lead, silver, mercury, copper, chromium, zinc, nickel, and cadmium. Heavy metals can kill fish, contaminate their flesh and impair water supplies.
• Non-Conventional Pollutants: These are substances that aren't classified as conventional or toxic pollutants but sometimes need to be included in permits because of the nature of the waste or to protect the receiving stream. Nutrients such as phosphorus and nitrogen are common non-conventional pollutants.

Some common pollutants
      Here are just a few of the pollutants that might be included in a NPDES permit:

• Biochemical Oxygen Demand: Commonly called BOD, this is a measure of the organic strength or food value to the small organisms that can consume the waste. It is similar to the caloric content of food. BOD doesn't measure a particular chemical, but rather the general organic decay strength of the waste. It is called a "lumped parameter" because it is a measure of the impact of multiple pollutants, not the amount of a particular chemical. This is a common parameter violated by sewage treatment plants.
• Chemical Oxygen Demand: A measure of the oxygen required to oxidize all compounds, both organic and inorganic, in water.
  Chlorine: Chlorine is added to water or sewage, generally for the purpose of disinfection, but frequently for accomplishing other biological or chemical results. Chlorine also is used almost universally in manufacturing processes, particularly in the plastics and pulp industries.
• Dissolved Oxygen: The oxygen freely available in water, vital to fish and other aquatic life. Adequate dissolved oxygen, or DO, levels are absolutely vital for a healthy aquatic ecosystem. Low dissolved oxygen can kill fish and other aquatic life and hinder the water's ability to break down pollutants and other organic matter. Because dissolved oxygen is critical for fish and other species to breakdown organic matter, it is an important measure of water quality. Excessive pollutant loading into a water body causes eutrophication resulting in the rapid growth of plant life and the depletion of dissolved oxygen.
• Fecal Coliform: This conventional pollutant is a bacterium found in the digestive tracks of warm-blooded animals. Its presence in the water potentially indicates the presence of pathogenic organisms. High fecal counts are the primary reasons for closing shellfish beds.
• pH: pH measures the intensity of the basic or acidic condition of a liquid. pH levels may vary up to 14, with the lowest numbers being the most acidic, 14 the most basic, and 7 neutral. Natural waters usually have a pH between 6.5 and 8.5 (the permitted pH range for waters in North Carolina). This limit is intended to protect the receiving stream from extremely basic or acidic discharges that can negatively affect the dissolved oxygen levels available to plants and animals.
• Phosphorus: Phosphorous is naturally occurring in many forms in soil and water, but in high concentrations, it stimulates algal growth and contributes to low dissolved oxygen levels.
• Temperature: Water temperature is one of the most critical triggers of aquatic productivity. Temperature affects virtually all metabolic processes of plant and animals, stimulates and controls reproduction, affects the solubility and diffusion of gases like dissolved oxygen, and affects distribution patterns of plants and animals. Higher than average water temperatures can kill animals and plants.
• Total Suspended Solids (TSS): A measure of the suspended solids in sewage or water bodies.
• Turbidity: Haziness in air caused by the presence of particles and pollutants or a cloudy condition in water due to suspended silt or organic matter.

     These are just some examples of pollutants that you might see in a permit. Other limits may be placed for color, oil and grease, and many chemicals not listed here.

Enforcing NPDES permits
     Establishing liability for NPDES permit violations is relatively straightforward: A violation of an NPDES permit constitutes a violation of the Clean Water Act. In fact, fault is not required to support liability. Instead, enforcement of NPDES permits is based on "strict liability." In other words, even if the permit holder didn't mean to violate his permit, he is liable for the results.
      Though that may seem unfair to some, it imposes a responsibility on each permit holder to ensure that permit conditions are met. Without such liability, a permit holder could avoid any penalty for polluting our waters by merely claiming that he or she was unaware of the problem. Strict liability places an affirmative duty on the permit holder to protect our resources.

• Enforcement Methods: Enforcement actions may be triggered by the regulatory agency, complaints filed by employees or citizens, and monitoring reports submitted by the permit holder to the regulatory agencies. Under the Clean Water Act, self-monitoring is supposed to be the main enforcement method.
• Self-Monitoring: The primary responsibility for complying with the Clean Water Act and the terms of a permit rests with the permit holder. The permit requires the plant to sample its discharges and submit monthly Discharge Monitoring Reports to the Division of Water Quality and EPA. The permit holder is also responsible for reporting any violations and taking corrective action.
• Civil Enforcement: Unfortunately, many permit holders don't comply with their permit limits and, unless faced with a penalty, fail to take corrective action. If a permit a holder fails to comply with its permit, the Division of Water Quality is primarily responsible for enforcing that permit. If the division documents a violation, it typically issues a notice of violation. The notice gives the violator a deadline to fix the problems. If a permit holder chronically violates the permit, the division can issue administrative orders that require plants to correct violations and that assess monetary penalties. The Clean Water Act provides for penalties of up to $27,500 a day for each violation. The Division of Water Quality also has to authority to: (1) Require immediate actions to correct the violation, for example, replacing or repairing defective equipment or taking other corrective measures to prevent further illegal discharges; (2) Order plant operators to cease operations until the problems are fully addressed; (3) Revoke the discharger's permit; (4) Refuse to renew a permit.
        They sound tough. Realistically, though, those options are rarely taken. For example, the division never assesses fines at the statutory maximum. Most fines are closer to $2,000 than $27,000. If the division resorts to a fine, it usually means the permit holder violated its permit numerous times. The penalty, then, is typically very small and frequently ranges from a few dollars to a few hundred dollars per violation, pocket change for most businesses. Remember, fines serve a valuable purpose in deterring future violations. If the fines are significantly less than the cost of fixing the problem, then the violator has an incentive to just continue discharging harmful pollutants into the water.
        Also, instead of requiring immediate action, the division typically requires chronic violators to enter into special orders by consent which describes measures that must be taken, such as upgrading equipment or providing operator training, with a schedule for achieving compliance. Sometimes these compliance schedules allow the permit holder two or three years to achieve compliance. Rarely, if ever, does the division deny or revoke a permit or refuse to renew one based on failure to comply with permit limitations.
• Criminal Prosecution: The Clean Water Act and state water quality statutes also contain criminal penalties for certain violations. Criminal prosecution is extremely rare and is typically reserved for severe violations. The US attorney, the state attorney general, or local district attorneys in the county in which the violation occurred prosecute criminal violations, which are not based on strict liability. Instead, prosecutors generally base their decision on whether the violation was committed intentionally or negligently.
       The most common criminal cases involve discharging without a permit, bypassing pollution control equipment, or falsifying discharge-monitoring reports. Criminal penalties may include substantial fines and significant terms of imprisonment for those found guilty.