Standard Conditions for Secondary Treatment Units

Standard Conditions for Secondary Treatment Units for Remedial Use Page 1 of 18

Revised November 30, 2016

Standard Conditions for Secondary Treatment Units

Approved for Remedial Use

Last Revision Date: November 30, 2016

ASecondary Treatment Unit (STU) isan alternative technology that may be used as a component of anon-site sewage disposal system where soil or site conditions make conventional soil absorption systems more costly to construct or infeasible. A conventional system may be more costly to construct or infeasible where there is a shallow water table and/or limited area for the siting of a conventional system. As compared to a conventional system, in certain instances, an STU provides for higher loading rates (smaller leaching area) and may require less land area, potentially less fill, and less disturbance of the site.

The System consists of anSTU designed to reduce the organic material and solids in the wastewater which reduces the demand for treatment in the soil absorption system. A conventional septic tank precedes the STU unless exempt by the Special Conditions for a specific Technology.

The use of an STU in accordance with this Approval for Remedial Use requires, among other things:

• A Disclosure Notice in the Deed to the property (310 CMR 15.287(10)) (A Deed Notice template is available from the Department);
• Certifications by the Designer and the Installer (310 CMR 15.021(3));
• A Massachusetts certified operator who has received training for the technology and is under contract for periodic inspection and maintenance (310 CMR 15.287(10));
• Periodic sampling, recordkeeping, and reporting, in accordance with this Approval;
• Notification within 24 hours by the System Owner to the local approving authority of any System failure;
• When pumping is required to discharge to the SAS, 24-hour emergency wastewater storage capacity above the elevation of the high level alarm; and
• System Owner Acknowledgement of Responsibilities, in accordance with this Approval.

Definitions and References:

The term “System” refers to the STU in combination with the other components of an on-site treatment and disposal system that may be required to serve a facility in accordance with 310 CMR 15.000.

The term “Approval” refers to these Standard Conditions applicable to all STU’s with Remedial Use Approval, the Special Conditions contained in the Technology-specific Approval, the General Conditions of 310 CMR 15.287, and any other Attachments.

The Conditions contained herein MUST be read in conjunction with any Special Conditions that are Technology-specific.

I.Purpose

1.Approval for Remedial Use allows the use of the Alternative System only where the local Approving Authority finds that the Alternative System is for the upgrade or replacement of an existing failed, failing or nonconforming system with a design of flow of less than 10,000 gpd, where there is no increase in the actual or proposed design flow, and where a conventional system with a reserve area, designed in accordance with the standards of 310 CMR 15.100 through 15.255, cannot feasibly be built on-site.

2.The sale, design, installation, and use of the System shall be subject to these requirements for any system that submits a complete Disposal System Construction Permit (DSCP) application after the effective date of these Standard Conditions. Existing Systems and Systems for which a complete DSCP application was submitted prior to the effective date of these requirements shall not be subject to the design and installation requirements, however, the System Owner, the Service Contractor, and the Company shall be subject to all other requirements contained herein.

3.With the other applicable permits or approvals that may be required by 310 CMR 15.000, the Approval authorizes the installation and use of the Alternative System in Massachusetts. Except those provisions that specifically have been varied by this Approval, the provisions of 310 CMR 15.000, including the General Conditions of 310 CMR 15.287, apply to the sale, design, installation, and use of the System.

4.Unless stated otherwise in the Special Conditions that apply to a specific Technology, all the conditions contained in this document shall apply to secondary treatment units which have obtained Remedial Use Approval. (Special Conditions may be more or less stringent than the requirements of this document.)

5.Provided that the local Approving Authority approves the Alternative System in conformance with the Department’s Technology Approval, Department review and approval of the site-specific System design and installation is not required unless the Department determines on a case-by-case basis, pursuant to its authority at 310 CMR 15.003(2)(e), that the proposed System requires Department review and approval.

II.Design and Installation Requirements

1.Effluent BOD5, TSS and pH - The effluent discharge concentrations from the Secondary Treatment Unit to the SAS shall not exceed secondary treatment standards of 30 mg/L BOD5 and 30 mg/L TSS and the effluent pH range shall be 6.0 to 9.0.

2.The Designer shall be a Massachusetts Registered Professional Engineer or a Massachusetts Registered Sanitarian,including when designing systems for repair,provided that such Sanitarian shall not design a system with a discharge greater than 2,000 gallons per day.

3.Except where the Approval specifically states otherwise, the Alternative System shall be installed in a manner which does not intrude on, replace, or adversely affect the operation of any other component of the subsurface sewage disposal system designed and constructed in accordance with the standards of 310 CMR 15.200 - 15.279.

4.Except where the Approval specifically states otherwise, the Alternative System shall include a properly sized and constructed septic tank, designed in accordance with 310 CMR 15.223 – 15.229,connected to the building sewer and followed in series by the Technology and the SAS;

5.Alternative Design Standards - Provided that the Designer demonstrates that the impact of the proposed Alternative System has been considered and the design requirements of 310 CMR 15.000 have been varied to the least degree necessary so as to allow for both the best feasible upgrade within the borders of the lot and the least effect on public health, safety, welfare and the environment, the local approving authority may allow any combination of the following alternative design standards without the need for granting a variance under 310 CMR 15.400 or obtaining Department approval:

a)If a reduction in the size of the SAS is necessary, the size of the SAS may be reduced up to 50 percent from the effective leaching area required when using the loading rates for gravity systems of 310 CMR 15.242(1)(a) for Systems sited in soils with a percolation rate of 60 minutes or less per inch, or for soils with a recorded percolation rate of between 60 and 90 minutes per inch, the loading rates of 310 CMR 15.245(4). (Alternatively, the effluent loading rates provided in 310 CMR 15.242(1)(b) for pressure distribution may be utilized, however, no reduction in the effective leaching area may be taken when using these loading rates, as stated in the regulation.); and/or

b)If a reduction in the depth to groundwater required by 310 CMR 15.212 is necessary, the depth to groundwater may be reduced by up to 2 feet, resulting in a minimum separation distance of two feet in soils with a recorded percolation rate of more than two minutes per inch and three feet in soils with a recorded percolation rate of two minutes or less per inch, measured from the bottom of the soil absorption system to the high groundwater elevation; and/or

c)If a reduction in the depth of the naturally occurring pervious material layer is necessary, a proposed reduction of up to 2 feet may be allowed in the four feet of naturally occurring pervious material layer required by 310 CMR 15.240(1) provided that it has been demonstrated that no greater depth in naturally occurring pervious material can be met anywhere on the site.

6.Any proposed reduction in the required depth to groundwater, specified in 310 CMR 15.212, may only be approved when:

a)An approved Soil Evaluator who is a member or agent of the local Approving Authority determines the high groundwater elevation;

b)No reduction is granted under LUA for setbacks from public or private wells, bordering vegetated wetlands, surface waters, salt marshes, coastal banks, certified vernal pools, water supply lines, surface water supplies or tributaries to surface water supplies, or drains which discharge to surface water supplies or their tributaries, is allowed; and

c)In accordance with 310 CMR 15.212(2), for systems with a design flow of 2,000 gpd or greater, the separation to high groundwater as required by 310 CMR 15.212(1) shall be calculated after adding the effect of groundwater mounding to the high groundwater elevation as determined pursuant to 310 CMR 15.103(3).

7.The Alternative Design Standards for effective leaching area, depth to groundwater, and depth of naturally occurring pervious material contained in the Department’s Standard Conditions for Secondary Treatment Unit Approved for Remedial Use shall not be made less stringent by the local Approving Authority under the LUA provisions of 310 CMR 15.405 or under the variance procedures of 310 CMR 15.411. The local Approving Authority may vary other design requirements under the LUA provisions of 310 CMR 15.405 or under the variance procedures of 310 CMR 15.411.

8.Except those allowed under LUA and the Approval, any further deviation from the siting and design requirements of 310 CMR 15.000 for the remedial use of a Secondary Treatment Unit shall require the following:

a)The applicant may propose the use of a Bottomless Sand Filter (BSF) as the means of on-site effluent disposal in conjunction with a Secondary Treatment Unit. The installation and use of the BSF must be in accordance with the conditions of the Remedial Use Approval issued by the Department for the BSF; and/or

b)The applicant may request the approving authority to grant a variance.

9.The proposed use of a Secondary Treatment Unit Approved for Remedial Use shall be subject to the following:

a)the approved record drawings, on file with the local approving authority, shall clearly indicate an area for the best feasible upgrade that could be installed to replace the proposed System, including the STU,in the event that the proposed System fails or it is determined that it is not capable of providing equivalent environmental protection;

b)the installation of the proposed System shall not disturb the site in any manner that would preclude the future installation of the best feasible upgradethat could be installed to replace the proposed System. Components of the proposed Systemmay be sited in an area for the future installation of the best feasible upgrade, provided that it does not render the area unusable for a potential future upgrade; and

c)except for the installed SAS, the System Owner shall not construct any permanent buildings or structures in the area for the best feasible upgrade that could be installed to replace the proposed Systemand the System Owner shall not disturb the site in any other manner that would preclude the future installation of the best feasible upgrade.

10.When identifying the best feasible upgrade that could be installed to replace the proposed System, the Designer shall consider these options in the following order:

a)a conventional system designed in accordance with the standards of 310 CMR 15.100 through 15.255 that can be built feasibly, with the exception of providing a reserve area (15.248);

b)a conventional system that can only be built feasibly under a Local Upgrade Approval (LUA);

c)where a conventional system cannot be built feasibly under a LUA, a Bottomless Sand Filter, in conjunction with an STU;

d)where a System can only be built feasibly with variances, a System that has been demonstrated to vary the design requirements of 310 CMR 15.000 to the least degree necessary and have the least effect on public health, safety, welfare and the environment (the System may be an Alternative System with variances); or

e)a tight tank.

11.For the upgrade or replacement of an existing failed or nonconforming system in a nitrogen sensitive area (NSA), as defined in 310 CMR 15.215, Systems serving facilities with actual or design flows of 2,000 GPD or greater must include treatment with a Recirculating Sand Filter (RSF) or equivalent technology, as required by 310 CMR 15.202(1). Secondary Treatment Units with Remedial Use Approval are notapproved as an RSF equivalent technology and shall not be installed in a NSA, as defined in 310 CMR 15.215, to serve facilities with actual or design flows of 2,000 GPD or greater. (The technology may also have a separate approval for nitrogen reduction, but must be installed under that approval,when appropriate.)

12.Except for septic tank covers which are not required to be at grade, the frames and covers of the other access manholes and ports of the System components shall be watertight, made of durable material, and shall be installed and maintained at grade, to allow for necessary inspection, operation, sampling and maintenance access. Manholes brought to final grade shall be secured to prevent unauthorized access. No structures which could interfere with performance, access, inspection, pumping, or repair shall be located directly upon or above the access locations.

13.Any System structures with exterior piping connections located within 12 inches of or lower than the Estimated Seasonal High Groundwater elevation shall have the connections made watertight with neoprene seals or equivalent.

14.All System control units, valve boxes, distribution piping, conveyance lines and other System appurtenances shall be designed and installed to prevent freezing.

15.The System control panel including alarms and controls shall be mounted in a location always accessible to the operator (or service contractor).

When pumping is required to discharge to the SAS, the System shall be equipped with sensors and high-level alarms to protect against high water due to pump failure, pump control failure, loss of power, system freeze ups, or backups. Emergency storage shall be required when pumping to discharge is employed, including pressure distribution. Emergency storage capacity for wastewater above the high level alarm shall be provided equal to the daily design flow of the System and the storage capacity shall include an additional allowance for the volume of all drainage which may flow back into the System when pumping has ceased.

16.System malfunction alarms or high water alarms shall be readily visible and audible for the facility occupants and the Service Contractor and the alarms shall be connected to circuits separate from the circuits serving operating equipment and pumps.

17.The System shall not include any relief valve or outlet for the discharge of wastewater to prevent flooding of the system, back up or break out.

18.In compliance with 310 CMR 15.240(13), a minimum of one (1) inspection port shall be provided within the SAS consisting of a perforated four inch pipe placed vertically down to the elevation of the SAS interface with the underlying unsaturated pervious soils to enable monitoring for ponding. The pipe shall be capped with a screw type cap and accessible to within three inches of finish grade. (A locking cap at-grade is preferred for annual inspection.)

19.Upon submission of an application for a Disposal System Construction Permit (DSCP), theDesigner shall provide to the local Approving Authority:

a)proof that the Designer has satisfactorily completed any required training by the Company for the design and installation of the Technology;

b)for any proposed non-residential System or any residential System with a design flow 2,000 GPD or greater, certification by the Company as specified inParagraph V.3;

c)certification by the Designer that the design conforms to the Approval, any Company Design Guidance, and 310 CMR 15.000; and

d)a certification, signed by the Owner of record for the property to be served by the Technology, stating that the property Owner:

i)has been provided a copy of the Approval, the Owner’s manual, and the Operation and Maintenance manual and the Owner agrees to comply with all terms and conditions;

ii)has been informed of all the Owner’s estimated costs associated with the operation including, when applicable: power consumption, maintenance, sampling, recordkeeping, reporting, and equipment replacement;

iii)understands the requirement for a service contract;

iv)agrees to fulfill his responsibilities to provide a Deed Notice as required by 310 CMR 15.287(10) and the Approval;

v)agrees to fulfill his responsibilities to provide written notification of the Approval to any new Owner, as required by 310 CMR 15.287(5);

vi)if the design does not provide for the use of garbage grinders, the restriction is understood and accepted; and

vii)whether or not covered by a warranty, the System Owner understands the requirement to repair, replace, modify or take any other action as required by the Department or the local Approving Authority, if the Department or the local Approving Authority determines that the Alternative System is not capable of meeting the performance standards.

20.The System Owner and the Designer shall not submit to the local Approving Authority a DSCP application for the use of a Technology under this Approval, if the Approval has been revised, reissued, suspended, or revoked by the Department prior to the date of application. The Approval continues in effect until the Departmentrevises, reissues, suspends, or revokes the Approval.