Water Treatment Plant General Discharge Permit

Kelli D. Buscher, P.E.

SD DENR

Clean Water Act Background

1972 - Clean Water Act established the National Pollutant Discharge Elimination System (NPDES) Program

Clean Water Act Background

All “Point Sources”“discharging pollutants”into “waters of the US”must obtain a discharge permit

Clean Water Act Background

A discharge permit is required to use public resources for waste disposal and limits the amount of pollutants that may be discharged

The discharge of pollutants to waters is a privilege, not a right

Clean Water Act Background

All “waters of the state” have water quality standards

A water quality standard defines the water quality goal of a water body by designating the beneficial use or uses of the water body and by setting criteria necessary to protect those uses

Beneficial Uses

(1) Domestic Water Supply Waters;

(2) Coldwater Permanent Fish Life Propagation;

(3) Coldwater Marginal Fish Life Propagation;

(4) Warmwater Permanent Fish Life Propagation;

(5) Warmwater Semipermanent Fish Life Propagation;

(6) Warmwater Marginal Fish Life Propagation;

Beneficial Uses

(7) Immersion Recreation Waters;(8) Limited Contact Recreation Waters;

(9) Fish and Wildlife Propagation, Recreation, and Stock Watering Waters;

(10) Irrigation waters; and

(11) Commerce and Industry Waters.

What Needs to be Covered?

Treatment system overflowsFilter Backwash and Settling BasinsDisinfection and Flushing of Water LinesStorage system disinfection and

overflowsWater line breaksOther WTP Discharges that fit the limits

and management practices

Why a General Permit?

Ensure all discharges from water treatment systems are covered

Establish uniform criteria for discharges from these activities

Reduce the administrative time for permit authorization

What is NOT Covered?

If the discharge contains radioactive components

If the discharge is to a lake or POTW If the discharge is a significant

contributor of pollution If the discharge presents a health

hazard If the discharge is not in compliance

What is NOT Covered?

If EPA develops federal limits for water treatment plant discharges

If a water quality management plan containing requirements applicable to the discharges is approved

If conditions or standards have changed so that the discharge no longer qualifies for the general permit.

Prohibitions

No discharge of sanitary wastewater No direct discharge of solids and/or sludges No discharge of floating solids or visible

foam No discharge of toxic pollutants in toxic

amounts SDDENR must be notified in advance of all

chemicals used Prevent or minimize stream scouring or bank

erosion caused by the discharge

Limits

pH6.5-9.0 for most discharges6.5-8.8 for coldwater marginal fisheries6.6-8.6 for coldwater permanent fisheries

Limits

Total Suspended Solids90 mg/L for most30 mg/L for coldwater permanent fisheries

Total Dissolved Solids2,500 mg/L for most1,000 mg/L for domestic water supplies

Limits

Conductivity2,500 μmhos/cm

Chlorinated water0.05 mg/L Total Residual Chlorine

Chloraminated water0.05 mg/L Total Residual Chlorine1.0 mg/L Ammonia

Outfalls

DW1Raw or partially treated water from the

treatment systemLime softening pondsFilter backwashOverflows from treatment unitsRaw water

Outfalls

DW2Completely treated water from treatment,

storage, or distributionStorage system overflowsWater line breaksHydrant flushingHydrostatic testingDisinfection of new lines

Monitoring Requirements

Outfall DW1 Flow Duration of

Discharge pH Temperature Total Fluoride Sulfates

TSS TDS TRC (if chlorinating) Ammonia (if

chloraminating) Conductivity Alkalinity

Monitoring Requirements

Outfall DW2 Total Flow Duration of

Discharge pH

TSS TRC (if chlorinating) Ammonia (if

chloraminating)

Best Management Practices

Permit requires the development of a BMP plan

Describe what will be done to reduce pollution from temporary discharges such as overflows and line flushing

Representative Outfalls

Representative outfalls cover activities at similar sites

Sampling would only have to be performed at selected outfalls

Provide documentation showing that the discharges from these activities will be similar in quality and nature

Frequently Asked Questions

Are all water systems required to get coverage under the discharge permit?

Do all water systems need coverage under both outfalls?

How is the state going to handle chlorine for discharges into road ditches?

What if we can not get a sample during a discharge?

Frequently Asked Questions

The permit requires that no chemicals be added without DENR notification. How will that work?

Can we use chemicals for dechlorination? Why would I want coverage under this

permit instead of the temporary one? What are the next steps?

For more information

Kelli Buscher kelli.buscher@state.sd.us 605.773.3351

Anthony Mueskeanthony.mueske@state.sd.us605.773.3351

http://www.state.sd.us/denr/DES/Surfacewater/WTP.htm