Chandler sewer discharge limits for businesses: FOG, pH and surcharges

The city's program page says the Industrial Pretreatment Program (IPP) controls pollutants from "all non-residential users" inside the city or connected to a city-managed treatment plant. Two limits are printed on that page:

• FOG: "Fats, oils, and grease (FOG) of vegetable origin or petroleum substances, whether emulsified or not, in excess of 100 mg/L must not be discharged to the POTW." (POTW is the publicly owned treatment works, the city's treatment plant.)
• pH: wastewater with a pH under 5.0 or over 12.5 standard units, or showing any other corrosive property, must not be introduced into the system.

The IPP also inspects grease interceptors, grease traps and similar devices at commercial and food service facilities. The governing document is the City of Chandler 2013 Wastewater Pretreatment Program, which City Code 51-24 adopts by reference.

The city's Local Limits page says no industrial user may discharge wastewater or any pollutant to the POTW above these limits, and that they "apply at the point where the wastewater is discharged to the POTW." The limits are based on flow-proportional or time-proportional composite samples, or grab samples where composites are not practical, and all values are for the total pollutant.

The same page lists two mass-based trigger levels that help set limits in Industrial User Permits: BOD at 63.0 lbs/day and TSS at 73.0 lbs/day.

Chandler charges for pollutants above set levels. The program page lists the trigger points, and City Code 50-13 sets the dollar amounts.

Code 50-13 also sets a $480.00 fee for an Industrial User permit application and renewal, and a monthly metered water charge of $0.183 per 1,000 gallons for permitted users. Users that certify no discharge of process wastewater regulated by federal categorical standards are exempt from the monthly metered water charge. These fees apply to industrial users that must be permitted under the pretreatment program, so a typical small office is not affected.

• POTW: the city's publicly owned treatment works, its sewage treatment plant.
• FOG: fats, oils and grease.
• BOD: biochemical oxygen demand, how much oxygen the waste uses up in the water.
• TSS: total suspended solids, the solid particles carried in wastewater.
• pH: the acid to base scale, measured in standard units (SU).

It covers every non-residential sewer user: restaurants and other food service establishments, manufacturers, laboratories and similar businesses. Homes are outside the program. The FOG limit is the one most small businesses meet, because it is why food service establishments need grease removal equipment. The device rules themselves are on our page for food service FOG treatment requirements.

A new restaurant. The owner opens a kitchen with a dishwasher and a three-compartment sink. The FOG limit is why a kitchen needs grease removal equipment, and the IPP inspects those devices. The sizing and maintenance rules live in the FOG treatment device page.

A neutralization tank. A business that rinses acidic or alkaline products down the floor drain needs the wastewater to land between pH 5.0 and 12.5 before it reaches the sewer. Ask Development Services whether the equipment needs a plumbing permit before you buy it.

The edge case: Chandler's pH ceiling is higher than Mesa's and Phoenix's. Mesa City Code 8-4-15 and Phoenix City Code Chapter 28 both prohibit discharge above 10.5 standard units. If you run locations in more than one city, do not assume the Chandler number carries over. Check the city's Local Limits page before you design a treatment system.

1. 1Decide whether you are a food service establishment or a permitted industrial user, and call the pretreatment program at pretreatment@chandleraz.gov if you are unsure.
2. 2If you cook or process food, read the FOG treatment device rules and size the interceptor on the plumbing plans before you apply for a permit.
3. 3If your process water could run outside pH 5.0 to 12.5, design a neutralization step and put it on the plans.
4. 4If you are a permitted industrial user, budget for the $480.00 permit application and renewal and for any excess pollutant charges.
5. 5For FOG questions, use the city's FOG line at 480-782-3720 or fog@chandleraz.gov (both printed on the program page).

• "Emulsified grease is not grease." The city's limit says "whether emulsified or not."
• "pH only matters for factories." The pH range applies to all non-residential wastewater.
• "A surcharge is a fine." City Code 50-13 describes these as fees to recover the city's costs of running the program, and says they are separate from other city fees.
• "Chandler's limits match Phoenix's." The pH ceiling on the city page is 12.5 in Chandler and 10.5 in Phoenix and Mesa.

Discharge limits can change when the city revises its pretreatment program. This page reflects the city's published pages as checked on the date above.