Onsite Residential and Commercial Graywater Treatment Systems for Subsurface Discharge
|Publication Date:||17 June 2011|
This Standard contains minimum requirements for onsite residential and commercial graywater treatment systems. Systems may include:
- Graywater reuse treatment systems having a rated treatment capacity up to 5,678 L/d (1,500 gal/d): This applies to onsite residential and commercial reuse treatment systems that treat combined graywater, those that treat laundry water only from residential laundry facilities, and those that treat bathing water only. See 8.1 for performance testing and evaluation.
- Commercial graywater reuse treatment systems: This applies to onsite commercial reuse treatment systems that treat combined commercial facility graywater with capacities exceeding 5,678 L/d (1,500 gal/d) and commercial facility laundry water only of any capacity. These systems shall be performance tested and evaluated at the location of the reuse system installation, using the graywater generated onsite from the facility serving the treatment system. See 8.2 for performance testing and evaluation. The key elements of a field evaluation of a commercial onsite reuse treatment system are described in Annex A.
The standard is intended to address public health and environmental issues only. Actual performance for any site or system may vary, depending on variations in raw water supply (such as in alkalinity and hardness), graywater constituents, and patterns of use. The end use of the effluent is the responsibility of the owner, design professionals, and regulatory officials.
Management methods and end uses appropriate for the treated effluent discharged from graywater residential and commercial treatment systems meeting this Standard are limited to subsurface discharge to the environment only. Effluent quality criteria consistent with these uses are described in 8.5 - Criteria.
System components covered under other NSF or NSF/ANSI standards or criteria shall also comply with the requirements therein. This Standard shall in no way restrict new system designs, provided such designs meet the minimum specifications described herein.
Alternate materials, design, and construction
While specific materials, designs, and constructions may be stipulated in this Standard, systems that incorporate alternate materials, designs, or constructions may be acceptable when it is verified that such systems meet the applicable requirements of this Standard.
For the purpose of this Standard, systems are classified according to the chemical, biological, and physical characteristics of their effluents as determined by the performance testing and evaluations described herein.
Graywater reuse treatment systems within a manufacturer's model series may be classified according to the performance testing and evaluation of the system expected to produce the poorest effluent quality within the series based upon design characteristics. A series is limited to treatment capacities below 1,514 L/d (400 gal/d), and treatment capacities between 1,514 L/d (400 gal/d) and 5,678 L/d (1,500 gal/d).
Graywater reuse treatment systems having rated treatment capacities less than 378 L/d (100 gal/d) shall be within a manufacturer's model series having rated treated capacities at or above 378 L/d (100 gal/d).
The manufacturer shall submit design drawings and specifications of the entire model series, which shall include critical design parameters for the systems. An engineering review of the design parameters may be completed in lieu of performance testing and evaluation of other systems within the series provided they are determined to be appropriately proportionate to the evaluated system based on sound engineering principles.
Commercial graywater reuse treatment systems with capacities exceeding 5,678 L/d (1,500 gal/d), and those that treat commercial facility laundry water up to 5,678 L/d (1,500 gal/d), as performance tested and evaluated in accordance with 8.2 and Annex A, may be similarly classified; however, consideration must be given to the conditions of the field evaluation of the system, including the graywater characteristics, treatment system loading conditions, and other variables affecting performance. These conditions shall become limitations for other models determined to be appropriately proportionate to the evaluated system.