King County
Public Rules and Regulations

Public Rules

Title: Discharge of Contaminated Groundwater to the Sanitary Sewer

Document Code No.: PUT 8-15 (PR)
Department/Issuing Agency: Department of Natural Resources/Industrial Waste Program
Effective Date: February 12, 1999
Approved: /s/ Ron Sims
Type of Action: Revised (reissued to incorporate agency name change due to reorganization of rule originally issued on October 1, 1995).

1.0 SUBJECT TITLE: Discharge of Contaminated Groundwater to the Sanitary Sewer

2.0 PURPOSE:

2.1 To establish rules governing the disposal of contaminated ground water into the metropolitan sewer system.

3.0 ORGANIZATIONS AFFECTED:

3.1 Any person, as that term is defined at King County Code (K.C.C.) Title 28.82.600, extracting groundwater or subsurface drainage, to: (a) reduce the spread of contaminants in the aquifer; (b) remove contaminants from the ground water; (c) remove contaminants from the surrounding soils; or (d) prevent the spread of contaminants to surface water. The ground water may or may not be treated prior to discharge.

3.2 King County Department of Natural Resources; Wastewater Treatment Division; Water and Land Resources Division; Industrial Waste Program.

4.0 REFERENCES:

4.1 K.C.C. 28.84.060 D.5.K. - Discharge Standards and Limitations (Specific Prohibitions for Discharges of Clean Water).

4.2 King County Ordinance No. 11034 - Establishes the Fees, Rules, and Regulations for the Disposal of Industrial Wastes into the Metropolitan Sewerage System.

The King County Code may be accessed on-line at: www.metrokc.gov. Laws of Washington may be accessed on-line at: http://www.leg.wa.gov. The federal register and regulations may be accessed on-line at: www.usace.mil/net/functions/cw/cecwo/reg.

5.0 DEFINITIONS:

5.1 "Dry season" shall mean that period of time from May through October of each year.

5.2 "Ground water" shall mean water in a saturated zone or stratum beneath the surface of land or below a surface water body.

5.3 "Subsurface Infilitration System" shall mean trenches, beds, or mounds placed beneath the soil surface to physically, chemically, or biologically treat and dispose of wastewater within the soil profile.

5.4 "Wet season" shall mean that period of time from November through April of each year.

6.0 POLICIES:

6.1 It is the policy of King County to provide sewerage facilities adequate for the transportation, treatment, and disposal of industrial and other wastes and to operate the metropolitan sewerage system in such a marmer that protects public health and the environment. In carrying out this policy, the objectives of this rule are:
6.1.1 To prevent pollutants from entering the sewerage system that will interfere with its normal operation, damage the collection or treatment systems, or contaminate the resulting biosolids;

6.1.2 To prevent the introduction of pollutants into the sewerage system that will not be adequately treated and will pass through into the environment;

6.1.3 To improve opportunities for recycling and reclamation of wastewater and biosolids;

6.1.4 To ensure protection of worker safety and health;

6.1.5 To implement waste reduction and recycling to prolong the useful life of existing and planned wastewater facilities and to protect the environment;

6.1.6 To focus sampling and inspection efforts on those industries discharging the greatest volume and concentration of pollutants while still recognizing the cumulative impact of small discharges; and

6.1.7 To implement an enforcement response plan aimed at achieving compliance in the shortest time frame possible and promoting responsibility of the industrial user to be in compliance.

6.2 Applicable permit applications are available from the King County Department of Natural Resources, Industrial Waste Section, 130 Nickerson, Suite 200, Seattle, Washington, 98109.

7.0 PROCEDURES:

Action By: Discharger

Action:

7.1 During the dry season, obtain all applicable discharge authorizations required by King County Ordinance No. 11034, codified at K.C.C. 28.84.060.

7.2 During the wet season, for discharges not greater than 26,000 gallons per day (gpd), obtain all applicable discharge authorizations required by Ordinance No. 11034.

7.3 During the wet season, for discharges greater than 25,000 gpd, obtain all applicable discharge authorizations required by Ordinance No. 11034, and comply with the following:

7.3.1 Demonstrate to King County's satisfaction that either site constraints or economic considerations, or both, prohibit the use of subsurface infiltration systems;

7.3.2 Demonstrate that a National Pollutant Discharge Elimination System (NPDES) permit to discharge to surface waters cannot be obtained from the Washington State Department of Ecology (WSDOE) or that the costs associated with obtaining an N-PDES permit are prohibitive; and

7.3.3 Submit to King County the information necessary to evaluate applications for discharges of greater than 25,000 gpd during the wet season, as described below in 7.5.

Action By: DNR

Action:

7.4 Require that all applicants comply with the applicable requirements of K.C.C. 28.84.060 (Ordinance No. 11034).

7.5 Use the following additional criteria to evaluate applications for discharges of greater than 25,000 gpd during the wet season:

7.5.1 The anticipated duration of discharge based on historical records or projections of ground water extraction rates. In the absence of historical discharge data, the projections of ground water extraction duration and rates must include the extent of the contamination, location and size of the recovery wells, the ground water gradients, and the hydraulic conductivity of the contaminated formation.

7.5.2 Design calculations of the required surface area needed for on-site infiltration of the extracted ground water. The calculations must be based on the hydraulic conductivity at the location(s) potentially suitable for infiltration, and the estimated volumes of wastewater. The hydraulic conductivity must be based on tests performed during on-site borings or installation of monitoring or recovery wells. Also required is information about geologic cross sections which illustrate the stratigraphy, the hydraulic conductivity of each deposit or unit (if known), the depth to ground water, deposits which may interfere with infiltration, or any underlying impervious boundaries.

7.5.3 A site plan illustrating the most feasible location of the infiltration system and the locations of all on-site borings.

7.5.4 The estimated costs associated with obtaining and maintaining an NPDES permit or a statement from WSDOE denying the applicant an NPDES permit.

7.5.5 The estimated costs associated with installing and maintaining an on-site infiltration system. Cost estimates must include the unit costs and the required quantities for excavating infiltration trenches, piping, pipe installation, removal and disposal of any contaminated soil, backfilling, and any required paving.

7.5.6 The estimated costs of obtaining and maintaining a King County discharge authorization, including the cost of sewer fees.

7.6 Allow currently permitted facilities until the expiration date of their current permit to come into compliance with this rule.

8.0 RESPONSIBILITIES:

8.1 Dischargers of water from ground water remediation activities are responsible for obtaining discharge authorizations from King County prior to discharge.

8.2 Dischargers of water from ground water remediation activities are responsible for ensuring that the discharged water meets the requirements of K.C.C. 28.84.060 (Ordinance No. 11034).

8.3 The King County Department of Natural Resources, Industrial Waste Program, is responsible for the enforcement of this public rule.

9.0 APPENDICES:

None.