When does Tolleson require pretreatment or a grease interceptor?

Subsection (C) is the trigger: "An industrial wastewater pre-treatment system or device shall be required by the Director to treat industrial flows prior to discharge to the sewer when" one of three things is true. It is necessary to restrict or prevent the discharge of certain waste constituents, or to "distribute more equally over a longer time period any peak discharges," or to "accomplish any pre-treatment result required by the Director."

Then the section gets specific:

• (D), design and approval: all systems need the Director's approval, and "All pre-treatment systems shall require an engineering design and have plans prepared and signed by an engineer of suitable discipline licensed in the State of Arizona."
• (D), interceptors: "Grease, oil and sand interceptors shall be provided when, in the opinion of the city, they are necessary for the proper handling of liquid wastes, containing grease in excessive amounts or any flammable wastes, sand and other harmful ingredients." They must be of a type and capacity the city approves, accessible for cleaning and inspection, and maintained by the owner at the owner's expense "in continuously efficient operation at all times."
• (E) and (F), specific controls: a device to neutralize or reduce phenols, metals or pesticides, and, where the Director requires, a pH probe with a recorder.
• (F), limits: waters or wastes exceeding these limits are subject to city review and approval, and where necessary the owner provides preliminary treatment at the owner's expense: five-day B.O.D. of 250 milligrams per liter, suspended solids of 250 milligrams per liter, and a pH range of 6.5 to 9.0.
• (F)(5)(a), the permit: each industrial user must "Obtain an industrial discharge permit from the Director" and get a new or amended permit before starting any new or modified discharge. Section 11-2-2 says an industrial wastewater discharge permit shall not exceed 12 months.
• (I), second approver: pretreatment systems or devices must be approved by the Director and by the Arizona Department of Environmental Quality.

Section 11-3-2 adds that no construction of treatment facilities may begin until written approvals are obtained. Section 11-3-4 says that when the Wastewater Department requires it, the owner installs a control manhole for observing and sampling industrial wastes.

• Director: Section 11-1-4 defines it as the Utilities Director or the Director's authorized deputy, agent or representative.
• Industrial user: Section 11-1-4 defines it as a non-domestic user of the sewer system whose waste would be subject to a categorical standard, pre-treatment standard or local limit.
• Interceptor: the code requires one for grease, oil and sand under (D). It does not give a size formula in this section.
• Corrosive wastes: the Tolleson amendment to IPC 803.1 replaces the model code's neutralizing-device rule with "Special wastes discharge shall be in conformance with City of Tolleson Utilities Department Pretreatment Program."

Industrial users, and under the interceptor sentence, any building where the city finds grease, flammable wastes or sand in excessive amounts. The interceptor rule has one exception: "the interceptor shall not be required for a building used for residential purposes." The Director's pretreatment authority is about industrial flows. A restaurant is not named in this section, so the city's "opinion" is what decides whether one needs an interceptor.

A bottling plant adds a washdown line. The new flow adds a discharge the permit may not cover. Subsection (F)(5)(a) requires a new or amended permit before starting, and the Director can require pretreatment under (C).

A restaurant's grease interceptor. The city decides whether one is needed and approves type and capacity. The owner maintains it. HQ handles interceptor repair and inspection, with a separate pumper doing the pump-out first.

The edge case: an office with only restroom and break-room flow. Neither (C) nor (D) describes it, and the interceptor sentence turns on "in the opinion of the city," so the city makes the call.

1. 1List every process and fixture that discharges to the sewer, with the pollutants each carries.
2. 2Contact the Utilities Department through City Hall at 623-936-7111 and ask whether the Director will require pretreatment or an interceptor for your use.
3. 3Hire an Arizona-licensed engineer of the right discipline to prepare and sign the plans.
4. 4Submit the plans and specifications for city approval. Do not start construction until the approvals are in writing.
5. 5Apply for the industrial discharge permit if you are an industrial user, and plan for the control manhole if the Wastewater Department requires one.
6. 6After it is built, keep it running. Section 11-3-3 puts continuous, effective operation on the property owner at the owner's expense, subject to inspection by the Wastewater Department.

• Assuming a restaurant is outside Chapter 11 because it is not industrial. The interceptor sentence applies to grease "in excessive amounts" wherever the city finds it.
• Treating the engineer requirement as optional. Subsection (D) says all pre-treatment systems require an engineering design with signed plans.
• Looking here for a sizing table or pumping interval. This section has neither. Size and type go through city approval.
• Starting construction before approval. Section 11-3-2 says no construction begins until written approvals are obtained.

The rule is Tolleson City Code 11-3-1 on Municode, with 11-3-2 through 11-3-4 and the IPC 803.1 amendment beside it. This is an explanation, and the code text and the Director's decisions govern.