Normal strength sewage (also known as domestic wastewater or domestic sewage), compatible pollutants and incompatible pollutants comprise the basic description of wastes received at the treatment plant. The imposition of an IWPT program shall be based upon the compatible and incompatible pollutants as they relate in character and concentration to normal strength sewage.
(a) Normal strength sewage shall mean sewage having average concentration values of not more than the following in the indicated pollutant categories:
(1) BOD5 - 200 mg/l;
(2) Suspended solids - 250 mg/l;
(3) Total phosphorus as "P" - 15 mg/l;
(4) Total nitrogen as "N" - 20 mg/l; and
(5) Oil and grease in less than floatable amounts and biodegradable.
(b) Compatible pollutants shall mean BOD5, suspended solids, pH, fecal coliform bacteria and other pollutants that may be identified by the Director of the Wastewater Department if the treatment plant, in fact, does remove such pollutants to a substantial degree. The term substantial degree is not subject to a precise definition but generally contemplates removals on the order of eighty percent (80%) or greater. Incidental removals in the range of ten percent (10%) to thirty percent (30%) are not considered substantial. Examples of other pollutants that may be added to the list of compatible pollutants are COD, total organic carbon, nitrogen and phosphorus compounds.
(c) Incompatible pollutants are materials that shall not be discharged into the public sanitary sewer system above the concentrations indicated by maximum Allowable Headworks Loading determined by analysis on the wastewater plant.
(d) In addition to the above referenced maximum concentrations in subsections (a) through (c) hereof for the specified pollutants the following compatible pollutants may not be discharged into the public sanitary sewer system above the indicated concentration levels except by special written permission of the Director:
(1) BOD | 1000 mg/l |
(2) Suspended solids | 1250 mg/l |
(3) Ammonia nitrogen | 50 mg/l |
(4) Oil and grease | |
mineral origin | 10 mg/l |
animal or vegetable origin | 50 mg/l |
(Ord. 90-1343. Passed 11-6-90; Ord. 00-46. Passed 8-1-00.)