§ 36-279. Local limits.

(a)

No user shall discharge into any sewer forming part of the POTW any of the following materials in concentrations exceeding the stated limits:

(1)

Any water or wastes that contain more than ten mg/l of sulfur dioxide or nitrous oxide, or more than five mg/l of hydrogen sulfide. More stringent limits may be imposed by the city manager for individual discharges where necessitated by the physical characteristics of the sewage collection system serving the area;

(2)

Any water or wastes that contain more than 100 mg/l of chlorides, 15 mg/l phosphorus, ten mg/l of nitrates, 70 mg/l of sodium, or 1.8 mg/l of fluoride;

(3)

Any toxic or poisonous substance or any other materials in sufficient quantity to injure or interfere with the wastewater treatment processes, or to constitute a hazard to humans or animals, or to cause a violation of the water quality standards or effluent standards for the stream or watercourse receiving the effluent from the wastewater treatment plant or to exceed limitations set forth in categorical pretreatment standards;

(4)

Any waters containing suspended solids of the character and quantity that unusual provisions, attention or expense is required to handle the materials at the wastewater treatment plant; or

(5)

Any waters containing quantities of radium or naturally occurring or artificially produced radioisotopes in excess of presently existing or subsequently accepted limits for drinking water as established by current drinking water regulations promulgated by the EPA.

(b)

No person shall discharge wastewater containing in excess of the fixed upper limits for constituents (milligrams per liter) following startup of the land application disposal system. The maximum daily average is shown in the following table.

Element	Maximum Daily Average (24 hour flow proportion composite) (mg/l)
Arsenic	0.203
Cadmium	0.022
Chromium, Hexavalent	1.447
Chromium, total	1.447
Copper	0.520
Cyanide	0.020
Lead	0.116
Mercury	0.009
Nickel	0.360
Phenol	—-
Silver	0.504
Tin	1.00
Zinc	0.493
TTO	2.13

 

(c)

The admission into the POTW of any waters or waste having biochemical oxygen demand (BOD), chemical oxygen demand (COD), or suspended solids (SS), or ammonia nitrogen (NH ₃ -N) in excess of the prohibition limits listed in the following table will not be allowed, unless otherwise stated in the individual industrial discharge permit. Sewer use surcharges will be applied for discharges having BOD, COD, SS or NH ₃ -N concentrations in excess of normal maximum levels, but below the prohibition limits established in the SIC permit. Where necessary in the opinion of the city manager, the user shall provide and operate, at his own expense, the pretreatment facilities as may be required to reduce the BOD, COD, SS and NH ₃ -N concentrations to levels below the normal maximum levels.

Pollutant (based on 24-hour composite sample)	Normal Daily Maximum (Surcharge) Limit (mg/l)	Prohibition Limit (mg/l)
BOD	300	500
COD	600	1,000
SS	300	500
NH 3 -N	20	50

 

(d)

Upon the promulgation of the national categorical pretreatment standards for a particular industrial subcategory, the categorical standards, if more stringent than limitations imposed under this article for sources in that subcategory, shall immediately supersede the limitations imposed under this article. All affected users shall notify the city of the applicable reporting.

(e)

State requirements and limitations on discharges shall apply in any case where they are more stringent than federal requirements and limitations or those of this article.

(f)

The city reserves the right to establish by ordinance or in wastewater discharge permits, more stringent standards or requirements on discharges to the POTW.

(Code 1989, § 10-32; Ord. of 10-2-1995, § 2.2; Ord. No. 2005-09, §§ 1, 2, 11-7-2005)