The following solid or viscous wastes which will or may cause obstruction to the flow in the sewer lines, or otherwise interfere with the proper operation of the treatment of sewage, are prohibited from entering the sewer system: any liquid containing oils, fats, wax, or grease (whether emulsified or not) in excess of 100 mg/l of solvent soluble materials, or containing substances which may solidify or become viscous at temperatures between 32° F. and 150° F.; improperly shredded garbage, animal guts or tissues, bones, hides, entrails, feathers, spent grains or hops, milk or milk by-products, waste paper and such similar substances as may be designated by the Borough of Milford Sewer Utility.