Pursuant To: On-site Water Protection Branch/Attorney General’s Office review
Source: Nancy Deal, On-site Water Protection Branch Head Shane Smith, Food Protection and Facilities Branch Head
Question / Issue
What is the design daily flow for an on-site wastewater treatment and dispersal system serving a mobile food unit or pushcart and its commissary?
Background
On July 16, 2012, Senate Bill 810 (SL 2012-187) amended G.S. 130A-248(c1) as follows: "The Commission shall adopt rules governing the sanitation of pushcarts and mobile food units. A permitted restaurant or commissary shall serve as a base of operations for a pushcart. A mobile food unit shall meet all of the sanitation requirements of a permitted commissary or shall have a permitted restaurant or commissary that serves as its base of operation." This statute allows a mobile food unit (MFU) to operate as its own commissary if it meets the requirements for commissaries in the 2009 Food Code as amended by 15A NCAC 18A .2670.
MFU and commissaries produce wastewater, and “all wastewater from water-using fixtures and appliances connected to a water supply source shall discharge to the approved wastewater system” [G.S. 130A-335]. MFU using potable water and sewage storage tanks shall be serviced in accordance with 15A NCAC 18A .2672, which includes flushing and draining the MFU or pushcart sewage storage tank. Therefore, MFU, pushcarts and their commissaries shall discharge all wastewater, including sewage storage tanks and wastewater from tank flushing, to an approved wastewater system in accordance with 15A NCAC 18A .1900, 15A NCAC 02T .0100, or 15A NCAC 02H .0100
Response / Interpretation
An application for a wastewater system shall be submitted to the local health department for new or expanded MFU and commissaries. The following are guidelines for determining design daily flow (DDF) for MFU and commissaries based upon the provisions of 15A NCAC 18A .1949.
- MFU
- a. 50 gallons/100 square feet of floor space, plus
- b. 25 gallons per food employee on the MFU
- Commissary
- a. With food prep: 50 gallons/100 square feet of floor space, or
- b. No food prep (only toilet, hand wash sink, and mop sink): 100 gallons/day, plus
- c. 25 gallons per food employee in the Commissary
Add the DDF for the MFU, commissary, and employees to determine the total for the MFU. The minimum design daily flow shall be 100 gallons per day. Alternate DDF may be proposed on a project-specific basis for consideration by the LHD and the State to account for factors such as units with larger water tank capacity or similar factors.
MFUs, pushcarts and commissaries are food establishments. Therefore, the system into which they discharge their wastewater shall comply with the provisions below:
- Minimum septic tank size requirements as specified in 15A NCAC 18A .1952(b)
- Minimum grease trap requirements as specified in 15A NCAC 18A .1955(k);
- Long-term acceptance rate (LTAR) shall not exceed the mean rate for the applicable soil group [15A NCAC 18A .1955(b)];
- No reductions in linear footage of nitrification trench or dispersal system area when an Innovative system or Accepted system approved in accordance with 15A NCAC 18A .1969 is used for the nitrification field as per specific approvals; and
- Gravelless nitrification trench systems shall not be used [15A NCAC 18A .1956(3)(a)].
Wastewater generated in the MFU shall be transported in the unit and discharged directly into an approved wastewater system owned or controlled by the MFU owner/operator in accordance with 15A NCAC 18A .1938(j).
References
G.S. 130A-248(c1)