6.1.1 Flammable or Explosive Materials
Any pollutant, as defined in 40 CFR 401.11, that creates a fire or explosion hazard in any sewer or treatment works, including, but not limited to, wastestreams with a closed cup flashpoint of less than 140 degrees Fahrenheit or 60 degrees centigrade using the test methods specified in 40 CFR 261.21.
At no time shall two successive readings on an explosion hazard meter, at the point of discharge into the system (or at any point in the system), be more than five percent (5%), nor shall any single reading be more than ten percent (10%) of the Lower Explosive Limit (LEL) of the meter.
Pollutants subject to this prohibition include, but are not limited to, gasoline, kerosene, naphtha, benzene, toluene, xylene, ethers, alcohols, ketones, aldehydes, peroxides, chlorates, perchlorates, bromates, carbides, hydrides, and sulfides, and any other substance that King County, a fire department, Washington State, or the U.S. Environmental Protection Agency (EPA) have notified the user are a fire hazard or a hazard to the system.
6.1.2 Settleable Solids - Volumetric
Settleable Solids Limit: 7.0 ml/L
The settleable solids - volumetric procedure is a volumetric approximation of the amount of matter that will not stay in suspension after a period of time.
6.1.3 Organic Compounds
No person shall discharge any organic pollutants that result in the presence of toxic gases, vapors, or fumes within a public or private sewer or treatment works in a quantity that may cause acute worker health and safety problems. Organic pollutants subject to this restriction include but are not limited to:
Any organic compound listed in 40 CFR Section 433.11(e), Total Toxic Organics (TTO) definition (Appendix 9.1).
Acetone, 2-butanone (MEK), 4-methyl-2-pentanone (MIBK), xylenes.
Dischargers are required to implement “housekeeping” and best management practices in order to prevent the discharge of a concentrated form of any of the above organic pollutants.
Individual permit limits for specific industrial discharges may be established for the above organic pollutants. Such limits shall be established on a case-by-case basis pursuant to K.C.C. 28.84.060 and shall be based on:
1. Conditions in public or private sewers downstream of the discharge, including dilution by other wastes upstream;
2. Worker safety and public health standards;
3. Type of chemical compound (toxicity, volatility, solubility);
4. Proximity to other discharges that may cause adverse conditions in combination with the discharge in question;
5. Technological achievability of removal; and
6. Potential impacts to public, private, or side sewers; treatment works; biosolids; or receiving waters.
6.1.4 Hydrogen Sulfide
Atmospheric Hydrogen Sulfide Limit: 10.0 ppm
(As measured at a monitoring manhole designated by King County)
Soluble sulfide limits may be established on a case-by-case basis depending upon volume of discharge and conditions in the receiving sewer, including oxygen content and existing sulfide concentrations.
6.1.5 Corrosive substances
Limits
Maximum pH 12.0 (s.u.)
Instantaneous Minimum pH 5.0 (s.u.)
Daily Minimum pH 5.5 (s.u.)
The instantaneous minimum pH limit is violated whenever any single grab sample or any instantaneous recording is less than pH 5.0.
The daily minimum pH limit is violated whenever any continuous recording of 15 minutes or longer remains below pH 5.5 or when each pH value of four consecutive grab samples collected at 15-minute intervals or longer within a 24-hour period remains below pH 5.5.
Discharges of more than 50 gallons per day of caustic solutions equivalent to more than 5% NaOH by weight or greater than pH 12.0 are prohibited unless authorized by King County and subject to special conditions to protect worker safety, the collection system, and treatment works.
6.1.6 Fats, Oils, and Grease (FOG)
6.1.6.1 FOG Accumulations and Obstructions
Discharges of FOG shall not result in significant accumulations which either alone or in combination with other wastes are capable of obstructing flow or that interfere with the operations or performance of sewer works or treatment facilities.
6.1.6.2 Non Polar FOG (mineral origin)
Non Polar FOG Limit: 100 mg/l
The limit for non polar FOG is violated when the arithmetic mean of the concentration of three grab samples, taken no more frequently than at five (5) minute intervals, or when the results of a composite sample exceeds the limitation.
When using approved EPA protocols specified in 40 CFR Part 136, multiple grab samples collected during a 24-hour period may be composited prior to analysis.
Companies which violate the non polar FOG limit may be required to complete, for King County review and approval, a FOG control plan as outlined in Section 6.1.6.4.
6.1.6.3 Polar FOG (animal and vegetable origin)
Dischargers of polar FOG shall minimize free floating polar FOG. Dischargers may not add emulsifying agents exclusively for the purposes of emulsifying free floating FOG. Companies which discharge free floating polar FOG will be required to complete, for King County review and approval, a FOG control plan as outlined in Section 6.1.6.4.
6.1.6.4 FOG Control Plans
The goal of the FOG control plan is to implement reasonable and technically feasible controls of free floating FOG. The basic components of the FOG control plan should include:
- A written policy articulating management and corporate support for the plan and a commitment to implement planned activities and achieve established goals.
- A description of the facility type and a summary of the products made and/or service provided.
- Quantities of FOG brought into the facility as raw product, amounts contained in products, and quantities discharged to the sewer.
- Schematics of process areas illustrating drains and discharge points connected to the sewer.
- A description of current reduction, recycling, and treatment activities.
- Identification of a full range of potentially feasible reduction opportunities.
- A description of the reduction or control opportunities selected for implementation, process(es) affected, and estimated reductions to be achieved.
- Specific performance goals and implementation schedule.
