Section R18-9-E304. 4.04 General Permit: Pressure Distribution Sys- tem, Less Than 3000 Gallons Per Day Design Flow

A.      A 4.04 General Permit allows for the use of a pressurized dis- tribution of wastewater system with a design flow less than 3000 gallons per day that treats wastewater to a level equal to or better than that specified in R18-9-E302(B).

1.        Definition. For purposes of this Section, a “pressure dis- tribution system” means a tank, pump, controls, and pip- ing that conducts wastewater under pressure in controlled amounts and intervals to a bed or trench or other means of distribution authorized by a general permit for an on-site wastewater treatment facility.

2.        An applicant may use a pressure distribution system if a gravity flow system is unsuitable, inadequate, unfeasible, or cost prohibitive because of site limitations or other conditions, or if needed to optimally distribute wastewa- ter.

B.       Performance. An applicant shall ensure that a pressure distri- bution system:

1.        Disperses wastewater so that:

a.         Loading rates are optimized for the intended pur- pose, and

b.        The wastewater is delivered under pressure and evenly distributed within the disposal works, and

2.        Prevents ponding on the land surface.

C.      Notice of Intent to Discharge. In addition to the Notice of Intent to Discharge requirements specified in R18-9-A301(B) and R18-9-A309(B), the applicant shall submit:

1.        A copy of operation, maintenance, and warranty materi- als for the principal components; and

2.        A copy of dosing specifications, including pump curves, dispersing component details, and float control settings.

D.      Design requirements.

1.        Pumps. An applicant shall ensure that pumps used in the on-site wastewater treatment facility:

a.         Are rated for wastewater service by the manufac- turer and certified by Underwriters Laboratories;

b.        Achieve the minimum design flow rate and total dynamic head requirements for the particular site; and

c.         Incorporate a quick disconnect using compression- type unions for pressure connections. The applicant shall ensure that:

i.         Quick-disconnects are accessible in the pres- sure piping, and

ii.        A pump has adequate lift attachments for removal and replacement of the pump and switch assembly without entering the dosing tank or process chamber.

2.        Switches, controls, alarms, timers, and electrical compo- nents. An applicant shall ensure that:

a.         Switches and controls accommodate the minimum and maximum dose capacities of the distribution network design. The applicant shall not use pressure diaphragm level control switches;

b.        Fail-safe controls that can be tested in the field are used to prevent discharge of inadequately treated wastewater. The applicant shall include counters or flow meters if critical to control functions, such as timed dosing;

c.         Control panels and alarms:

i.         Are mounted in an exterior location visible from the dwelling,

ii.        Provide manual pump switch and alarm test features, and

iii.      Include written instructions covering standard operation and alarm events;

d.        Audible and visible alarms are used for all critical control functions, such as pump failures, treatment failures, and excess flows. The applicant shall ensure that:

i.         The visual portion of the signal is conspicuous from a distance 50 feet from the system and its appurtenances;

ii.        The audible portion of the signal is between 70 and 75 db at 5 feet and is discernible from a distance of  50 feet  from  the system and its appurtenances; and

iii.      Alarms, test features, and controls are on a non- dedicated electrical  circuit associated  with  a frequently used household lighting fixture and separate from the dedicated circuit for the pump;

e.         All electrical wiring complies with the National Electrical Code, 2005 Edition, published by the National Fire Protection Association. This material

	is incorporated by reference and does not include		b.     An applicant may use a septic tank second compart-
	any later amendments or editions of the incorporated		ment or a second septic tank in series as a dosing
	material. Copies of the incorporated material are		tank if all dosing tank requirements of this Section
	available for inspection at the Arizona Department		are met and a screened vault is used instead of the
	of  Environmental  Quality,  1110  W.  Washington,		septic tank effluent filter.
	Phoenix, AZ 85007 or may be obtained from the		4.     Design SAR. If the site conditions of the property for the
	National  Fire  Protection  Association,   1  Battery-		on-site wastewater treatment facility do not require pres-
	march Park, P.O. Box 9101, Quincy, MA 02269-		sure distribution, but an applicant chooses to use pressure
	9101. The applicant shall ensure that:		distribution, the applicant shall use a design SAR for the
	i.      Connections are made using National Electrical		absorption surfaces in the disposal works that is not more
	Manufacturers Association (NEMA) 4x junc-		than 1.10 times the adjusted SAR determined in R18-9-
	tion boxes certified by Underwriters Laborato-		A312(D).
	ries; and	E.	Additional Discharge Authorization requirements. An appli-
	ii.     All controls are in NEMA 3r, 4, or 4x enclo-		cant shall obtain copies of instructions for the critical controls
	sures for outdoor use.		of the system from the person who installed the pressure distri-
3.	Dosing tanks and wastewater distribution components.		bution system. The applicant shall submit one copy of the
	a.      An applicant shall:		instructions with the information required in subsection (C).
	i.      Design dosing tanks to withstand anticipated	F.	Operation and maintenance requirements. In addition to the
	internal and external loads under full and empty		applicable requirements specified in R18-9-A313(B), a per-
	conditions, and design concrete tanks to meet		mittee shall ensure that:
	the “Standard Specification for Precast Con-		1.     The operation and maintenance manual for the on-site
	crete Water and Wastewater Structures, C913-		wastewater treatment facility that supplies the wastewater
	02 (2002),” published by the American Society		to the pressure distribution system specifies inspection
	for  Testing  and  Materials.   This  material  is		and maintenance needed for the following items:
	incorporated by reference and does not include		a.      Sludge level in the bottom of the treatment and dos-
	any later amendments or editions of the incor-		ing tanks,
	porated material. Copies of the incorporated		b.     Watertightness,
	material are available for inspection at the Ari-		c.      Condition of electrical and mechanical components,
	zona  Department   of  Environmental  Quality,		and
	1110 W. Washington, Phoenix, AZ 85007 or		d.     Piping  and  other  components  functioning   within
	may be obtained from the American Society for		design limits;
	Testing and Materials International, 100 Barr		2.     All critical control functions are specified in the operation
	Harbor Drive, West Conshohocken, PA 19428-		and maintenance manual for testing to demonstrate com-
	2959;		pliance with design specifications, including:
	ii.     Design dosing tanks to be easily accessible and		a.      Alarms, test features, and controls;
	have secured covers;		b.     Float switch level settings;
	iii.   Install risers to provide access to the inlet and		c.      Dose rate, volume, and frequency, if applicable;
	outlet of the tank and to service internal compo-		d.     Distal pressure or squirt height, if applicable; and
	nents;		e.      Voltage  test   on  pumps,  motors,   and  controls,   as
	iv.    Ensure  that  the   volume  of  the   dosing  tank		applicable;
	accommodates bottom depth below maximum		3.     The finished grade is observed and maintained for proper
	drawdown, maximum design dose, including		surface drainage. The applicant shall observe the level-
	any drainback, volume to high water alarm, and		ness of the tank for differential settling. If there is set-
	a reserve volume above the high water alarm		tling, the applicant shall grade the facility to maintain
	level that is not less than the daily design flow		surface drainage.

volume. If the tank is time dosed, the applicant shall ensure that the combined surge capacity and reserve volume above the high water alarm is not less than the daily design flow volume;

v.                 Ensure that dosing tanks are watertight and anti-buoyant;

vi.               Design the wastewater distribution components to withstand system pumping pressures;

vii.             Design the wastewater distribution system to allow air to purge from the system;

viii.           Design pressure piping to minimize freezing during cold weather;

ix.               Ensure that the end of each wastewater distri- bution line is accessible for maintenance;

x.                 Ensure that orifices emit the design discharge rate uniformly throughout the wastewater dis- tribution system; and

xi.               Design orifices using orifice shields to provide proper distribution of wastewater to the receiv- ing medium.

Historical Note

New Section adopted by final rulemaking at 7 A.A.R. 235, effective January 1, 2001 (Supp. 00-4). Amended by final rulemaking at 11 A.A.R. 4544, effective November 12, 2005 (05-3).