7 Del. Admin. Code § 7201-7.0

Current through Register Vol. 28, No. 7, January 1, 2025

Section 7201-7.0 - Technology-based Requirements

7.1 General. At a minimum, any discharge of liquid waste - sewage, industrial waste or other waste - to State waters shall be subject to effluent limitations, discharge requirements and any alternate effluent control strategy that reflect a practicable level of pollutant removal technology. For the purposes of this section, a practicable level of pollutant removal technology is defined as the application of the "best" treatment technology, control measures and practices, including pollution prevention, available to prevent, manage, reduce or remove pollutants taking into account the cost of applying such technology, control measures, pollution prevention or other practices in relation to the effluent reduction benefits to be achieved, the age of equipment and facilities involved, the process(es) employed, the engineering aspects of applying the various types of controls, process changes, pollution prevention measures, non-water quality impacts (e.g. energy requirements) and other factors deemed appropriate. For the parameters, BOD₅ (5-day biochemical oxygen demand) and suspended solids, the degree of removal reflecting an application of a practicable level of pollutant removal technology shall be at least 85% of the BOD₅ and suspended solids contained in the influent to the treatment works or prior to application of the removal technology, control measures or practices. For discharges of sewage to State waters, a practicable level of pollutant removal technology shall be secondary treatment and disinfection.

7.2 Minimum Requirements for Treatment of Sewage Prior to Discharge to a Surface Water

7.2.1 No person shall cause or permit any discharge of liquid waste to the Delaware River, the Delaware Bay, or Atlantic Ocean except liquid waste which has received at least secondary treatment and disinfection.

7.2.2 No person shall cause or permit discharge of liquid waste to a lake or a pond or any tributary thereof, except liquid waste which has received at least secondary treatment, filtration, nutrient removal and disinfection.

7.2.3 No person shall cause or permit any discharge of liquid waste to the Little Assawoman Bay, Indian River Bay, or to Rehoboth Bay, including any tributaries to those waterbodies, except liquid waste which has received at least secondary treatment, filtration, and disinfection.

7.2.4 No person shall cause or permit any discharge of liquid waste to a stream, tidal or non-tidal, except liquid waste which has received at least secondary treatment, filtration, and disinfection. This subsection shall not govern discharge into the Delaware River, the Delaware Bay or the Atlantic Ocean, which shall be governed by paragraph a herein. For existing facilities, filtration may not be required if the existing facility has demonstrated the ability to continuously meet secondary treatment levels.

7.3 Minimum Requirements for Treatment of Any Liquid Waste Prior to Discharge to a Surface Water

7.3.1 At a minimum, any liquid waste or wastewater that contains pollutants added by the discharger or the discharger's activities, or that contains pollutants introduced into the discharger's treatment works by any indirect discharger shall be treated so as not to exceed the following limitations for the parameters listed:

7.3.1.1 BOD₅ 30 mg/L

7.3.1.2 Suspended Solids 30 mg/L

7.3.1.3 Cadmium 0.10 mg/L

7.3.1.4 Chromium (total) 0.150 mg/L

7.3.1.5 Lead 0.150 mg/L

7.3.1.6 Mercury 0.005 mg/L

7.3.1.7 Copper 0.50 mg/L

7.3.1.8 Iron (total) 2.0 mg/L

7.3.1.9 Nickel 1.0 mg/L

7.3.1.10 Selenium 0.020 mg/L

7.3.1.11 Silver 0.10 mg/L

7.3.1.12 Zinc 1.0 mg/L

7.3.1.13 Cyanide 0.050 mg/L

7.3.1.14 Fluoride 3.0 mg/L

7.3.1.15 Oil & Grease 10.0 mg/L

7.3.1.16 Phenolics 1.0 mg/L

The concentration levels imposed shall be utilized to establish average monthly or daily average loading limitations. Measurements to determine compliance with the above requirements shall be taken at a point after treatment as designated by the Department.

7.3.2 Any liquid waste or wastewater subject to the limitations herein shall be segregated from discharges that are not subject to such limitations to the maximum practicable extent. Dilution shall not be used to meet the concentration levels outlined in § 7.3.1 nor shall it be used as a substitute for treatment or the application of a practicable level of pollutant removal technology.

7.3.3 In situations where the effluent limitations established pursuant to § 7.3.1 cannot be achieved through the application of a practicable level of pollutant removal technology, the Secretary shall establish alternate limitations or discharge requirements that do reflect the application of such treatment technology, control measures or practices.

7.4 Minimum Technology-based Requirements for Discharges of Toxic Pollutants

7.4.1 Any effluent or discharge limitations, prohibitions and standards established for the discharge of any toxic pollutant(s) (toxic pollutants are those listed in table 1 of Committee Print No. 95-30 of the House of Representatives' Committee on Public Works and Transportation, included herein as Appendix A) shall reflect the application of the "best available pollution control technology economically achievable".

7.4.2 For the purposes of this section, the "best available pollution control technology economically achievable" is defined as the "best" or most advanced and reasonably cost-effectivetreatment technology, control measures and practices, including pollution prevention, available to prevent, manage, reduce or remove pollutants taking the following seven factors into account:

7.4.2.1 The age of equipment and facilities involved;

7.4.2.2 The process or processesemployed;

7.4.2.3 The engineering aspects of applying the various technologies, types of controls or practices;

7.4.2.4 Process or production changes;

7.4.2.5 Pollution prevention measures (e.g. raw material substitutions, equipment modification, production scheduling, inventory control, housekeeping measures and in-process recycling that returns wastes directly to production as raw materials);

7.4.2.6 The cost of achieving such pollutant removal(s) oreffluent reduction(s); and

7.4.2.7 Non-water quality impacts (e.g. energy requirements).

7.5 Methods of Imposing Technology-based Treatment Requirements in Permits

7.5.1 Technology-based treatment requirements may be imposed in permits issued by the Secretary through one of the following methods:

7.5.1.1 The application of the effluent limitations in § 7.3;

7.5.1.2 The application of EPA-promulgated effluent or discharge limitations, prohibitions or standards developed under § 304, 306 or 307 of the Act, for the category or subcategory of discharger to which the applicant belongs;

7.5.1.3 On a case-by-case basis to the extent that the limitations in § 7.3 or EPA-promulgated effluent limitations are inapplicable. In such cases, the permit writer shall take the factors in § 7.1 or § 7.4, as appropriate, into account and consider:

7.5.1.3.1 The appropriate technology for the category or class of point sources to which the applicant belongs, based upon all available information; and

7.5.1.3.2 Any unique factors relating to the applicant.

7.5.1.4 For sewage treatment works, effluent or discharge limitations, prohibitions and standards that reflect the level of effluent quality attainable by the technologies specified in § 7.2.

7.5.1.5 Through a combination of the methods outlined in this section where appropriate, e.g. where promulgated effluent limitations guidelines only apply to certain aspects of the discharger's operation, or to certain pollutants, other aspects or activities are subject to regulation on a case-by-case basis in order to carry out the provisions of the Law and the Act;

7.5.2 Technology-based treatment requirements shall be applied prior to or at the point of discharge.

7.5.3 Technology-based effluent limitations shall be established under this section for solids, sludges, filter backwash, and other pollutants removed in the course of treatment or in the exercise of control measures prescribed by these regulations, in the same manner as for other pollutants.

7.6 For a given pollutant parameter, the level of effluent quality attainable shall be based upon actual performance data which is representative of the proper operation and maintenance of the facilities being permitted. Average monthly or daily average effluent or discharge limitations shall be the 95th percentile value for the average monthly or daily average effluent quality achieved by the treatment facilities in a period of at least 2 years, excluding values attributed to upsets, bypasses, operational errors or other unusual conditions. The maximum daily effluent or discharge limitation shall be either:

(1) the 99th percentile value for the daily discharge or effluent quality achieved by the treatment facilities in the same period of at least 2 years, excluding values attributed to upsets, bypasses, operational errors or other unusual conditions, or

(2) a value equal to 1.5 times the average monthly or daily average. An alternate multiplier may be used to establish the daily maximum effluent limitation where sufficient data exists to define the correlation between the daily and the average monthly values.

7.7 Any technology-based effluent or discharge limitations established as prescribed herein for the discharge from a sewage treatment works shall be no less stringent than the following:

7.7.1 For facilities employing secondary treatment and disinfection:

The average monthly or daily average effluent or discharge limitations shall be: 30 mg/L BOD₅ (5-day biochemical oxygen demand), 30 mg/L total suspended solids and a geometric mean of 200 colonies per 100 mL fecal coliform;

The daily maximum effluent or discharge limitations shall be: 45 mg/L BOD₅ (5-day biochemical oxygen demand), 45 mg/L total suspended solids and 400 colonies per 100 mL fecal coliform; and

The pH of the effluent or discharge shall be maintained between 6 and 9 standard units unless the facility demonstrates that:

1. Inorganic chemicals are not added to the waste stream as part of the treatment process and

2. Contributions from industrial sources do not cause the pH of the effluent to be less than 6.0 or greater than 9.0.

The facilities shall remove a minimum of 85% of the influent BOD₅ and total suspended solids on an average monthly basis.

The parameter carbonaceous 5-day biochemical oxygen demand (CBOD₅) may be substituted for BOD₅ as follows: the average monthly or daily average effluent or discharge limitation shall be 25 mg/L; the daily maximum effluent or discharge limitation shall be 40 mg/L; the monthly average percent removal shall not be less than 85%. Alternate CBOD₅ effluent or discharge limitations may be established and substituted for BOD₅ in cases where sufficient parallel effluent data are available to define the relationship between BOD₅ and CBOD₅.

7.7.2 For facilities employing secondary treatment, filtration, nutrient removal and disinfection:

The average monthly or daily average effluent or discharge limitations shall be: 15 mg/L BOD₅ (5-day biochemical oxygen demand), 15 mg/L total suspended solids, 0.5 mg/L total phosphorus and a geometric mean of 200 colonies per 100 mL fecal coliform;

The daily maximum effluent or discharge limitations shall be: 23 mg/L BOD₅ (5-day biochemical oxygen demand), 23 mg/L total suspended solids, 1 mg/L total phosphorus and 400 colonies per 100 mL fecal coliform; and

The pH of the effluent or discharge shall be maintained between 6 and 9 standard units unless the facility demonstrates that:

1. Inorganic chemicals are not added to the waste stream as part of the treatment process and

2. Contributions from industrial sources do not cause the pH of the effluent to be less than 6.0 or greater than 9.0.

The facilities shall remove a minimum of 92.5% of the influent BOD₅ and total suspended solids on an average monthly basis.

The parameter carbonaceous 5-day biochemical oxygen demand (CBOD₅) maybe substituted for BOD₅ as follows: the average monthly or daily average effluent or discharge limitation shall be 13 mg/L; the daily maximum effluent or discharge limitation shall be 20 mg/L; the monthly average percent removal shall not be less than 92.5%. Alternate CBOD₅ effluent or discharge limitations may be established and substituted for BOD₅ in cases where sufficient parallel effluent data are available to define the relationship between BOD₅ and CBOD₅.

7.7.3 For facilities employing secondary treatment, filtration and disinfection:

The average monthly or daily average effluent or discharge limitations shall be: 15 mg/L BOD₅ (5-day biochemical oxygen demand), 15 mg/L total suspended solids and a geometric mean of 200 colonies per 100 mL fecal coliform;

The daily maximum effluent or discharge limitations shall be: 23 mg/L BOD₅ (5-day biochemical oxygen demand), 23 mg/L total suspended solids and 400 colonies per 100 mL fecal coliform; and

The pH of the effluent or discharge shall be maintained between 6 and 9 standard units unless the facility demonstrates that:

1. Inorganic chemicals are not added to the waste stream as part of the treatment process and

2. Contributions from industrial sources do not cause the pH of the effluent to be less than 6.0 or greater than 9.0.

The facilities shall remove a minimum of 92.5% of the influent BOD₅ and total suspended solids on an average monthly basis.

The parameter carbonaceous 5-day biochemical oxygen demand (CBOD₅) may be substituted for BOD₅ as follows: the average monthly or daily average effluent or discharge limitation shall be 13 mg/L; the daily maximum effluent or discharge limitation shall be 20 mg/L; the monthly average percent removal shall not be less than 92.5%. Alternate CBOD₅ effluent or discharge limitations may be established and substituted for BOD₅ in cases where sufficient parallel effluent data are available to define the relationship between BOD₅ and CBOD₅.

7.8 Dilution or any other "non-treatment" techniques such as flow augmentation and in-stream mechanical aerators shall not be used to satisfy the technology-based treatment requirements specified herein, nor shall such techniques be used as a substitute for treatment or the application of a practicable level of pollutant removal technology.

7.9 If the Department determines that the application of the treatment requirements, control measures and practices or pollution prevention practices or effluent limitations which are specified in this section or promulgated under §§ 301, 302, 303, 304, 306, 307, 318 and 405 of the Act, is insufficient to attain or maintain any applicable water quality standards for the receiving waters, including any narrative criteria for water quality, the Department shall establish such additional or more stringent effluent limitations, discharge requirements, control measures and practices that will assure compliance with the applicable water quality standards.

APPENDIX A

The following comprise the list of toxic pollutants designated pursuant to section 307(a)(1) of the Act (listed in table 1 of Committee Print Numbered 95-30 of the House of Representatives' Committee on Public Works and Transportation):

1. Acenaphthene

2. Acrolein

3. Acrylonitrile

4. Aldrin/Dieldrin

5. Antimony and compounds

6. Arsenic and compounds

7. Asbestos

8. Benzene

9. Benzidine

10. Beryllium and compounds

11. Cadmium and compounds

12. Carbon tetrachloride

13. Chlordane (technical mixture and metabolites)

14. Chlorinated benzenes (other than di-chlorobenzenes)

15. Chlorinated ethanes (including 1,2-di-chloroethane, 1,1,1- trichloroethane, and hexachloroethane)

16. Chloroalkyl ethers (chloroethyl and mixed ethers)

17. Chlorinated naphthalene

18. Chlorinated phenols (other than those listed elsewhere; includes trichlorophenols and chlorinated cresols)

19. Chloroform

20. 2-chlorophenol

21. Chromium and compounds

22. Copper and compounds

23. Cyanides

24. DDT and metabolites \1\

25. Dichlorobenzenes (1,2-, 1,3-, and 1,4-di-chlorobenzenes)

26. Dichlorobenzidine

27. Dichloroethylenes (1,1-, and 1,2-dichloroethylene)

28. 2,4-dichlorophenol

29. Dichloropropane and dichloropropene

30. 2,4-dimethylphenol

31. Dinitrotoluene

32. Diphenylhydrazine

33. Endosulfan and metabolites

34. Endrin and metabolites \1\

35. Ethylbenzene

36. Fluoranthene

37. Haloethers (other than those listed elsewhere; includes chlorophenylphenyl ethers, bromophenylphenyl ether, bis(dichloroisopropyl) ether, bis-(chloroethoxy) methane and polychlorinated diphenyl ethers)

38. Halomethanes (other than those listed elsewhere; includes methylene chloride, methylchloride, methylbromide, bromoform, dichlorobromomethane

39. Heptachlor and metabolites

40. Hexachlorobutadiene

41. Hexachlorocyclohexane

42. Hexachlorocyclopentadiene

43 Isophorone

44. Lead and compounds

45. Mercury and compounds

46. Naphthalene

47. Nickel and compounds

48. Nitrobenzene

49. Nitrophenols (including 2,4-dinitrophenol, dinitrocresol)

50. Nitrosamines

51. Pentachlorophenol

52. Phenol

53. Phthalate esters

54. Polychlorinated biphenyls (PCBs) \1\

55. Polynuclear aromatic hydrocarbons (including benzanthracenes, benzopyrenes, benzofluoranthene, chrysenes, dibenzanthracenes, and indenopyrenes)

56. Selenium and compounds

57. Silver and compounds

58. 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)

59. Tetrachloroethylene

60. Thallium and compounds

61. Toluene

62. Toxaphene \1\

63. Trichloroethylene

64. Vinyl chloride

65. Zinc and compounds

7 Del. Admin. Code § 7201-7.0