S.C. Code Regs. § § 61-67.67.300

Current through Register Vol. 48, No. 11, November 22, 2024

Section 61-67.67.300 - Construction Permits

A. General Requirements.

1. Facilities needing a construction permit include: Main Sewers, Wastewater Collection and Transmission Systems, Pump Stations and Force Mains, Wastewater Treatment Facilities, and Components. Activities not requiring a construction permit include replacement of a component (same or similar), as long as there is no change in capacity, routine maintenance, and the construction of buildings. However, for all other modifications, including relocation of sewers and revisions to existing construction permits, the Department shall be contacted for a decision on whether or not a construction permit is required.

2. Service connections which shall contribute more than five (5) percent of the existing wastewater treatment facility's design capacity, or fifty thousand (50,000) gpd, shall be approved by the Department. This approval is for the additional flow and not for the physical work or materials.

3. Individual service connections as defined in the regulation may require Department approval prior to connecting to a sewer system if the wastewater treatment facility receiving the flow from the individual service connection is under a tap moratorium imposed by the Department.

4. Double residential service connections are not considered main sewers and shall, therefore, not require a construction permit from the Department. However, the common line shall be owned, operated and maintained by the same entity that owns the main sewer system that the common line is tying onto. Other double service connections shall be reviewed by the Department on a case-by-case basis, to determine if a construction permit is required and to confirm ownership requirements are met.

5. Individual pressure connections to force mains are considered collectors and shall require that a construction permit be issued by the Department, unless the entity owning the sewer system is a Delegated Review Program entity with an approved Alternative Sewer Management Plan.

6. When the proposed system is located off the applicants property, easements or documentation of recorded easements, excluding encroachment permits and navigable waters easements, are required to be submitted to the Department prior to permitting for all applicants with the exception of public entities or other applicants that have the right of eminent domain.

7. No construction permit shall be issued for a wastewater treatment facility, including effluent disposal lines, unless the applicable effluent disposal permit has been issued. Construction may commence only if:

a) the applicable effluent disposal permit has not been appealed, or

b) the applicable effluent disposal permit becomes effective in a manner which would not require a change to the construction permit.

8. Proposed sewer systems shall connect to existing systems with available capacity or to another proposed sewer system, with available capacity (including considerations of infiltration and inflow), which has already received a construction permit from the Department. Where a construction permit has been issued on the downstream components though not yet operational, a construction permit on the proposed sewer system may be issued, but the approval to place in operation shall not be issued until all downstream components have received an approval to place in operation.

a. Downstream Sewer Systems. Construction permits shall not be issued in cases where adequate capacity in the downstream components of the wastewater facilities is not available to handle the design flow of the proposed project. Adequate capacity for sewer lines and pump stations means that the existing sewer facilities, including the wastewater treatment facility receiving the wastewater, have the capacity as currently permitted. If a downstream treatment system were issued a permit to construct, but construction could not commence consistent with subsection 67.300.A.7, then the wastewater treatment facility permit would not be considered "currently permitted." An evaluation of available capacity may be made based on factors such as flow projections from previously permitted projects (including considerations of infiltration and inflow).

b. Downstream Treatment Systems. For public and private entities, available capacity in wastewater treatment facilities may be based on its effluent disposal permit capacity (i.e., capacity may be advanced where the effluent disposal capacity is greater than the actual facility capacity to treat and dispose of wastewater). This advancing of capacity is acceptable unless actual flows exceed the permit flow limits of the existing wastewater treatment facility or the facility has violated other limits that have led to Department's issuance of an order to remedy the problems (and the problem has not been corrected). For facilities seeking to have capacity advanced, the Department may require an agreement with the permittee to detail the conditions of advancing capacity. The permitted flow at a wastewater treatment facility may be adjusted based on a review of Discharge Monitoring Reports data or other data collected by independent sources to address issues such as infiltration and inflow.

c. Exceptions. A construction permit may be issued for a sewer system and/or pretreatment system where the downstream components have yet to be issued a construction permit, or do not presently have adequate capacity if:

(1) a preliminary engineering report has been submitted to and approved by the Department for the upgrade of the downstream facilities. The preliminary engineering report shall include target dates for submitting plans, starting construction and completing construction for the necessary upgrade to the downstream facilities;

(2) for a private entity, excluding industrial facilities, financial assurance (e.g., an escrow account), which includes adequate funds to complete the upgrade of the downstream facilities, has been established; and

(3) the increase to the effluent disposal permit has been issued and has not been appealed (or either the period to appeal has lapsed without appeal, or the appeal has been resolved to sustain the permit) for the wastewater treatment facility so that there is adequate permit capacity available for the proposed sewer system.

9. Prior to the issuance of a construction permit for a collection system, including pump stations and force mains, to serve more than one (1) parcel of deeded property (e.g., subdivisions, condominiums), with the exception of industrial facilities, the project owner shall provide the Department with documentation that the collection system, including the pump stations and force mains, shall be owned, operated and maintained by a public entity. An exception can be made where there are several platted properties with a common owner in an area (e.g., hospital complex) where there is not a reasonable expectation that the project area would later serve different owners. Proposals by private entities shall be evaluated on a case-by-case basis. The Department may evaluate the capability of reliable system operation in its evaluation.

10. Average flow projections for all domestic wastewater facilities shall be based on the type of facility to be served, as stated in 61-67 Appendix A, unless otherwise justified by the applicant and approved by the Department.

11. Peak hourly flow projections shall be at least two and one half (2.5) times the average daily flow projection, unless otherwise justified by the applicant and approved by the Department. Where actual data are available, the Department may require its use in determining a peaking factor.

12. All sewers shall be constructed with a minimum of three (3) feet of cover, unless justified by the applicant and approved by the Department (e.g., use of ductile iron pipe may have cover less than three (3) feet).

13. Sewer lines, manholes, pump stations, force mains, and wastewater treatment facilities shall be located more than one hundred (100) feet from a public water supply well. Sewer lines, manholes, pump stations, and force mains shall be located at least twenty (20) feet from any other potable well, as defined in Regulation Regulation 61-71. Wastewater treatment facilities shall be located at least one hundred (100) feet from any other potable well, as defined in Regulation Regulation 61-71. Special designs may be considered which shall provide equivalent protection to the well when this requirement is not achievable.

14. When sewers are proposed adjacent to any existing or proposed potable water supply facilities, the following requirements apply:

a. Potable Water Supply Interconnections. There shall be no physical connections between a public or private potable water supply system and a sewer, or appurtenance thereto which may permit the passage of any sewage or polluted water into the potable supply. No potable water pipe shall pass through or come into contact with any part of a sewer manhole.

b. Horizontal and Vertical Separation from Potable Water Mains. Sewers shall be laid at least ten (10) feet horizontally from any existing or proposed potable water main. The distance shall be measured edge to edge. In cases where it is not practical to maintain a ten (10) foot separation, the Department may allow deviation on a case-by-case basis, if supported by data from the design engineer. Such deviation may allow installation of the sewer closer to a potable water main, provided that the potable water main is in a separate trench or on an undisturbed earth shelf located on one side of the sewer and at an elevation so the bottom of the potable water main is at least eighteen (18) inches above the top of the sewer.

c. Crossings. Sewers crossing potable water mains shall be laid to provide a minimum vertical separation of eighteen (18) inches between the outside of the potable water main and the outside of the sewer. This shall be the case where the potable water main is either above or below the sewer. Whenever possible, the potable water main shall be located above the sewer main. Where a new sewer line crosses a new potable water main, a full length of pipe shall be used for both the sewer line and potable water main and the crossing shall be arranged so that the joints of each line shall be as far as possible from the point of crossing and each other. Where a potable water main crosses under a sewer, adequate structural support shall be provided for the sewer line to prevent damage to the potable water main while maintaining line and grade.

d. Force Mains. There shall be at least a ten (10) foot horizontal separation between sanitary sewer force mains and potable water mains. There shall be an eighteen (18) inch vertical separation at crossing as required in subsection67.300.A.14.b and subsection67.300.A.14.c.

e. Special Conditions. When it is impossible to obtain the distances specified in subsection67.300.A.14.b, subsection67.300.A.14.c, and subsection67.300.A.14.d the Department may allow an alternative design. Any alternative design shall:

(1) maximize the distances between the sewer line and the potable water main and the joints of each;

(2) use pipe materials which meet the requirements as specified in Regulation Regulation 61-58.4(D)(1)(D)(1)for the sewer line; and

(3) allow enough distance to make repairs to one of the lines without damaging the other.

f. Sewer Manholes. No potable water pipe shall pass through or come into contact with any part of a sewer manhole.

15. [Reserved]

16. The construction permits issued by the Department shall be effective for a period of up to two (2) years to initiate construction from the issuance date, and up to three (3) years to complete construction from the issuance date. If there is adequate justification the Department may grant longer time frames when issuing the permit for initiating and completing construction. Once permitted, the Department will consider requests to extend dates for initiating and completing construction. Projects for which the construction permit has been expired for more than one (1) year are considered new projects and therefore must include a new application submittal.

17. Materials and installation for all gravity sewer lines and force mains shall comply with commonly accepted design standards such as ASTM (American Society for Testing and Materials), ANSI (American National Standard), AWWA (American Water Works Association) or other design standards as approved by the Department.

18. If a proposed wastewater system requires construction in State navigable waters and the Department determines that a permit shall be issued for the construction in navigable waters, considerations of the navigable waters permit process may be incorporated into the review for the wastewater construction permit.

19. If a proposed wastewater system requires construction within one of the eight coastal counties (Horry, Georgetown, Berkeley, Charleston, Dorchester, Colleton, Beaufort, and Jasper) Coastal Zone consistency review shall be provided by the Department's Office of Ocean and Coastal Resource Management (OCRM) as part of the wastewater construction permit process, unless a general certification applicable to the project from OCRM has already been provided.

B. Gravity Sewer Lines/Collection Systems.

1. Excluding service connections less than fifty thousand (50,000) gpd, sewer connections to gravity sewer lines shall be constructed such that the internal angle of deflection is equal to or greater than ninety (90) degrees, including connections at manholes. Angles less than the required ninety (90) degrees may be considered on a case-by-case basis, when there is adequate justification (e.g., drop through the manhole) provided.

2. For all domestic wastewaters and for industrial wastewaters with solids which are similar in size and nature to solids in domestic wastewater, no gravity sewer line conveying raw sewage shall be less than eight (8) inches in diameter. In cases where the flow and number of taps are limited to less than ten (10) percent of the design capacity of the receiving sewer line, as determined by the Department, and the line cannot be reasonably extended, the Department may consider the use of six (6) inch diameter lines.

3. For all domestic wastewaters and for industrial wastewaters with solids which are similar in size and nature to solids in domestic wastewater, all gravity sewers shall be designed and constructed to give mean velocities, when flowing full, of not less than two (2) feet per second, based on Manning's formula using an "n" value of thirteen thousandths (0.013). Slopes slightly less than those required for the two (2) feet per second velocity, when flowing full, may be permitted. Such decreased slopes shall only be considered where the depth of flow shall be three tenths (0.3) of the diameter or greater for average flows. Whenever such decreased slopes are selected, the design engineer shall furnish with the report design computations of the anticipated flow velocities of average and peak flows. The report shall indicate the actual velocity in the sewer lines at the proposed slope and the actual velocity at the required slope in order to achieve two (2) feet per second, when flowing full. The pipe diameter and slope shall be selected to obtain the greatest practical velocities to minimize settling problems. Oversized sewers shall not be approved to justify using flatter slopes. The operating authority of the sewer system shall give written assurance to the Department that any additional sewer maintenance required by reduced slopes shall be provided.

4. Sewers shall be designed with a uniform slope between manholes.

5. Sewers on twenty (20) percent slopes or greater shall be anchored securely with concrete anchors or equal, spaced as follows:

a. Not over thirty six (36) feet center-to-center on grades twenty (20) percent and up to thirty five (35) percent;

b. Not over twenty four (24) feet center-to-center on grades thirty five (35) percent and up to fifty (50) percent; and

c. Not over sixteen (16) feet center-to-center on grades exceeding fifty (50) percent.

6. Sewers twenty four (24) inches or less in diameter shall be laid with straight alignment between manholes. Consideration for curvilinear sewers in excess of twenty four (24) inches in diameter shall be evaluated on a case-by-case basis.

7. Manhole top elevations shall be greater than or equal to the fifty (50) year flood elevation, unless watertight covers are provided.

8. Manholes shall be installed: at the end of each line; at all changes in grade, size, or alignment; at all intersections of piping; and at distances not greater than four hundred (400) feet for sewers fifteen (15) inches or less, and five hundred (500) feet for sewers eighteen (18) inches to thirty (30) inches. Distances up to six hundred (600) feet may be approved, for sewers equal to or greater than eight (8) inches in diameter, in cases where adequate cleaning equipment for such spacing is provided. Greater spacing may be permitted in larger sewers. Cleanouts may be used only for special conditions and shall not be substituted for manholes except when installed at the end of laterals not greater than one hundred fifty (150) feet in length. A drop pipe shall be provided for a sewer entering a manhole at an elevation of twenty four (24) inches or more above the manhole invert. Where the difference in elevation between the incoming sewer and the manhole invert is less than twenty four (24) inches, the invert shall be filleted to prevent solids deposition. Manholes may not be required on sewer lines transporting special waste (e.g., volatile organic compounds) or effluent wastewater from a treatment facility.

9. The minimum inside diameter of manholes shall be forty eight (48) inches unless using an inside drop connection where a minimum inside diameter of sixty (60) inches shall be required for all new manholes. For modifications to existing manholes, a minimum diameter of forty eight (48) inches, for inside drop connections, may be provided if justified and approved by the Department. A minimum manhole access diameter of twenty two (22) inches shall be provided.

10. Each section of sewer pipe shall be specified to be laid to the appropriate line and grade, as designed, working in the upstream direction with the bell end laid upgrade.

11. All gravity sewers shall be designed and specified such that the leakage outward (exfiltration) or inward (infiltration) shall not exceed two hundred (200) gallons per inch of pipe diameter per mile per day. An air test may be utilized in lieu of an infiltration/exfiltration test, if approved by the Department.

C. Pump Stations.

1. Each pump station shall be fenced or secured in a locked building/enclosure or be located in a restricted access area to prevent access by unauthorized persons. The type of fencing or other means of controlling access shall be approved by the Department.

2. A weather durable sign, approved by the Department, with a twenty four (24) hour emergency telephone number, shall be located at a conspicuous point on the fence or structure of the pump station, unless the pump station is located in a restricted access area.

3. At least two (2) pumps or pneumatic ejectors shall be provided, unless the pump station serves only one (1) residential lot or one (1) building. An exception may be if the building serves a significant flow amount (e.g., apartment complex). If only two (2) units are provided, they shall have the same capacity and each shall be capable of handling the expected peak flow. Where three (3) or more units are provided, they shall be designed to fit actual flow conditions and shall be of such capacity that with any one unit out of service the remaining units shall have capacity to handle peak sewage flows. The Department may consider the effect of flow equalization, where applicable.

4. For domestic wastewaters and industrial wastewaters with solids which are similar in size and nature to solids in domestic wastewater, pump openings shall be capable of passing spheres of at least three (3) inches in diameter, for raw, unscreened wastewater, and pump suction and discharge piping shall be at least four (4) inches in diameter, except for grinder pumps.

5. Pump stations shall have an alarm system (e.g., audible and visible high water alarm, centralized automated alarm system). The alarm system shall be designed to function if power is not available for any pump. For pump stations located in remote and/or environmentally sensitive areas (e.g., adjacent to shellfish harvesting areas, designated recreational areas, and primary source water protection areas), the Department may require an automatic dialing system via dedicated phone line or equivalent systems to assure minimal impact in the event of pump station failures. In remote and/or environmentally sensitive areas, the Department may also require that a backup battery pack be provided in the control panel of the pump stations so that in the event of a power outage the audible/visible high water alarms and/or automatic dialing system shall still be activated.

6. The pump station wet well and dry well shall be ventilated, excluding the valve pit. The vent (e.g., a screened inverted "j" tube) shall be constructed of a weather durable material (e.g., stainless steel).

7. For pump stations with duplex pumps each pump shall be designed to operate in a lead lag sequence and be on an alternating cycle. For pump stations with more than two (2) pumps alternate designs may be considered.

8. A shutoff valve (e.g., gate valve) and a check valve shall be located on the discharge line from each pump. The check valve shall be located between the shutoff valve and the pump.

9. The shutoff valve(s) for the pump station, as required in subsection67.300.C.8. above, or an additional shutoff valve on the common discharge line, shall be located outside of the wet well in a separate valve pit or other apparatus (e.g., valve box) to facilitate proper use of the valve. In certain cases, the Department may require watertight design of the pit or other apparatus for the purpose of capturing valve leakage. For watertight design, it shall have a means of dewatering (e.g., drain line) back to the wet well, with provisions for preventing gases from entering the pit from the wet well.

10. The check valves for the pump station shall be located outside the wet well in a separate valve pit or dry well, unless the check valves are an integral part to the pump and can be removed from the wet well for repair or replacement with the pump, without dewatering the wet well or disconnecting any piping in the wet well, or unless the following conditions are provided by the applicant, and approved by the Department:

a. The entity accepting the pump station for operation and maintenance shall apply for a waiver to the requirement stating reasons for the request.

b. The entity shall certify in writing to the Department that its employees are trained to use all appropriate safety equipment to allow entry to confined spaces in accordance with State and Federal OSHA/Labor laws and regulations.

c. The utility's operation and maintenance record may be reviewed to determine that operation and maintenance problems with pump stations have not occurred or, if they have, the problems were rectified to the Department's satisfaction. If problems with the operation and maintenance of pump stations have occurred and were not rectified to the Department's satisfaction, then the Department may require the check valves to be located outside of the wet well, in a separate valve pit.

11. Common walls between the wet well and the valve pit or dry well shall be gas tight.

12. Pump stations shall be designed to be fully operational during flooding to the twenty five (25) year flood elevation unless the influent flow into the pump station can be stopped. For example, industrial facilities may select to cease operation during these periods in lieu of having the pump station fully operational. Pump station structures and equipment shall be protected from physical damage by flooding to the one hundred (100) year flood elevation. An all weather access road shall be provided to the pump station.

13. Suction lift pumps shall be of the self priming or vacuum priming type.

14. Electrical junction boxes shall be located outside of the wet well, unless the junction box and components are made of a material suitable for use under corrosive conditions.

15. An emergency operation plan on the sewer pump station(s) shall be provided. For areas determined by the Department to be environmentally sensitive (e.g., shellfish harvesting areas, designated recreational waters, or primary source water protection areas located in close proximity), the Department may require more extensive plans and equipment, including on site auxiliary power or a Department approved equivalent plan. The Department may evaluate the effect of power outages where the pump station serves sources such as businesses that would not be able to operate otherwise. The plan shall include one of the following methods showing how the pump station(s) shall be designed to provide continuous operability in the event of a power failure, natural disaster, etc.:

a. An on site standby generator, either permanently installed with capability to operate automatically or skid/trailer mounted types with appropriate connections provided.

b. Connecting the pump station to two (2) separate utility substations, with an automatic switching feature.

c. Providing sufficient capacity, in the wet well, above the pump on level, to contain the wastewater that may be generated during the longest power outage of the last five (5) years. A letter shall be submitted from the utility company that serves this pump station with electricity stating the longest power outage, in the service area of the pump station, that occurred during the last five (5) years, excluding a catastrophic storm.

d. Provide a method to pump around the pumps and control panel by using a pump and providing a way to pump into the force main downstream of the check valve.

e. Provide a transfer switch for a portable generator and demonstrate that the utility owns adequate generators and could reasonably respond during a power outage.

f. Industrial facilities need to provide back up power as specified above unless the industrial facility can show that their processes stop in the event of a power outage and that enough storage is available until power is restored, so an overflow shall not occur. Design calculations or other information shall be provided for justification .

16. For pump stations which are an integral part of a wastewater treatment facility the Department shall determine which of the above items shall apply.

D. Force Mains.

1. Velocity in force mains shall be at least two (2) feet per second at design flow. However, lower initial velocities may be permitted by the Department if provisions to maintain a flushing velocity can be made, or if the wastewater does not contain suspended solids.

2. Force mains carrying raw domestic sewage shall be at least four (4) inches in diameter, except force mains that follow grinder pump systems or solids interceptor tanks, for which a two (2) inch diameter force main is approvable.

3. Thrust blocking or restraint joints shall be provided at all changes in alignment greater than or equal to thirty (30) degrees.

4. An automatic air relief valve shall be placed at high points in the force main sewer to prevent air locking. Vacuum relief valves may be necessary to relieve negative pressures on force mains. The Department may require alternative designs in order to reduce possible odor problems from air relief valves located in highly populated areas.

5. Force mains tying onto manholes shall enter the manhole a vertical distance of not more than two (2) feet above the flow line of the receiving manhole. For connections to existing manholes, special consideration may be granted by the Department to allow the force main to enter the manhole at a higher elevation and be directed down on the inside of the manhole, if justified.

6. Design and construction of force mains shall be such that they satisfy a leakage test in accordance with American Water Works Association (AWWA) Standard C600.

7. When force mains serving individual residences (and other similar situations) connect to the primary force main serving the area, a check valve shall be placed on the individual customer's force main at the point where ownership changes in that force main.

E. Alternative Collection Systems. These types of systems may be considered to be an appropriate design when conventional sewers are not feasible based upon a site specific review.

1. General Requirements.

a. A public entity shall be responsible for the operation, maintenance, and replacement of all system components beginning with the solids interceptor tanks and pumping systems and vacuum system valve pits. Proposals by private entities shall be evaluated on a case-by-case basis. The Department may evaluate the capability of reliable system operation in its evaluation, including an evaluation of experience with operation and maintenance of wastewater facilities.

b. The responsible entity shall have the right of ingress/egress on each lot to be able to maintain the solids interceptor tanks and pumping systems.

c. Applications for construction of alternative sewer collection systems shall include a justification (e.g., topographic restrictions, low population density) of why a conventional gravity system (e.g., eight (8) inch diameter gravity sewers carrying raw wastewater) is not recommended.

d. If pumps are utilized for an alternative sewer collection system (e.g., solids interceptor tanks and effluent pumps, grinder pumps) then duplex pumps shall be provided if serving more than one (1) house. A simplex pump shall only be allowed if one (1) house is being served unless an operation and maintenance plan has been approved by the Department which then may allow a simplex pump to serve up to two (2) houses. Some factors that the Department may consider when reviewing this operation and maintenance plan include, but are not limited to, the entity agreeing to operate and maintain these systems: maintains a five (5) percent reserve stock of pumps (but not less than one (1)); maintains a reserve stock of replacement parts; and, has an inspection program established.

e. The Department may waive the design standards utilized for conventional wastewater facilities (e.g., minimum of eight (8) inch diameter sewer mains, manholes), since these types of sewer systems are carrying either effluent from solids interceptor tanks or grinder pump systems. Force mains serving individual sources utilizing a grinder or STEP system may be allowed to be less than the two (2) inches in diameter required under subsection67.300.D.2, when adequately justified.

2. Additional Requirements for systems utilizing Solids Interceptor Tanks.

a. Ultimate disposal of residuals from the solids interceptor tanks shall be addressed during the permitting process via the approval of a residuals management plan. The residual or solids management plan shall comply with the appropriate sections of Regulation 61-9.

b. Design calculations shall be included with the submittal showing the velocity in the lines to be a minimum of one (1) foot/sec, for lines conveying effluent only (no solids) from the tanks.

c. An individual solids interceptor tank shall be provided to each house, unless an operation and maintenance plan has been approved by the Department, whereby an individual solid interceptor tank may be allowed to serve up to two (2) houses. The minimum size solids interceptor tank shall be one thousand (1,000) gallons, unless otherwise approved by the Department.

3. Additional Requirements for systems utilizing Grinder Pump Stations. Design calculations shall be included with the submittal showing the velocity in the lines to be a minimum of two (2) feet per second, for lines conveying raw sewage (solids present).

4. Vacuum Sewers.

a. General Requirements:

(1) The entire vacuum sewer system, including the individual valve pits, shall be owned, operated and maintained by a single public entity.

(2) The maximum lift in the vacuum sewer system shall be twenty (20) feet.

(3) To minimize the lift, minimize the length of the lines, and to equalize the flow, vacuum stations shall be centrally located with multiple branches, unless justified by the applicant and approved by the Department.

(4) The vacuum sewer system must be designed to remain operational during a loss of vacuum.

(5) For routine and emergency operation and maintenance of a vacuum sewer system, the public entity responsible for the system shall have the right of access, an adequate supply of spare valves, pumps, parts, and service tools.

(6) An operation and maintenance manual is required for each vacuum sewer system.

(7) A minimum scouring velocity of two (2) fps is required in the vacuum sewer lines.

(8) The vacuum sewer system air to liquid ratio shall be a minimum of two (2) parts air to one (1) part liquid.

b. Piping and Valve Requirements:

(1) A minimum pipe diameter of four (4) inches is required for main vacuum sewer lines.

(2) Vacuum sewer lines must have a minimum slope of 0.20%.

(3) Two (2) forty-five (45) degree bends are required with a short section of piping, instead of a ninety (90) degree bend.

(4) Shut off valves are required on both the suction and discharge piping and at every branch connection and at intervals no greater than one-thousand five-hundred (1,500) feet on main lines. Plug valves or resilient coated wedge gate valves shall be used. No butterfly valves are allowed.

(5) Check valves are required on each pump discharge line.

(6) Isolation valving is required between the vacuum connection tank, vacuum pump(s), influent line and raw sewage discharge pipe.

(7) Gasketed type pipe shall be provided. The pipe and gaskets shall be certified for use under vacuum conditions.

(8) To locate vacuum sewers, magnetic trace tape shall be provided in the top of the trench, or metal toning wires located above the pipe or color coding of the piping.

(9) Division valves shall be used for isolation purposes. The valves shall be installed in a valve pit or other approved apparatus to facilitate proper use of the valve.

(10) Gauge taps shall be provided just downstream of the division valves.

(11) Thrust blocking or restraint joints shall be provided at all changes in alignment greater than or equal to thirty (30) degrees.

(12) The maximum design flows (i.e., peak flows) for vacuum pipe sizing are as follows:

(a) Four (4) inch pipe shall be 38 GPM.

(b) Six (6) inch pipe shall be 105 GPM.

(c) Eight (8) inch pipe shall be 210 GPM.

(d) Ten (10) inch pipe shall be 375 GPM.

(13) The maximum length of four (4) inch diameter lines, for any one run, is two-thousand (2,000) feet.

c. Vacuum Pit Requirements:

(1) One valve pit may be allowed to serve up to two (2) houses.

(2) Vacuum valve pits shall be designed to prevent entrance of water in the sump and for the vacuum valve to remain fully operational if submerged.

(3) Vacuum valve pits shall be easily accessible so that valving may be easily removed and replaced.

(4) Air vents, four (4) inches in diameter, shall be provided and shall extend a minimum of two (2) feet above the ground level and be protected against freezing and physical damage. The vent shall be located a minimum of twenty (20) feet from the valve pit.

d. Vacuum Pump Station Requirements:

(1) A minimum peaking factor of three (3.0) is required.

(2) The total volume of the vacuum collection tank shall be three (3) times the operating volume plus four-hundred (400) gallons, with a minimum size of one-thousand (1,000) gallons.

(3) Standby power shall be required capable of handling 100% peak loadings. A standby generator is required for all vacuum stations.

(4) A minimum of two (2) pumping units shall be provided for both the vacuum pumps and the wastewater pumps, with each being capable of handling peak flow conditions.

(5) An alarm system with capability to notify staff operators remotely (e.g., telemetry system) shall be provided. The monitoring system shall be provided with continuously charged batteries for twenty-four (24) hour standby operation, in the case of a power outage.

(6) Certification is required from the pump manufacturer stating that the wastewater pumps are suitable for use in a vacuum sewer installation.

F. Wastewater Treatment Facilities.

1. All wastewater treatment facilities shall be designed with effluent flow monitoring and effluent sampling. All domestic wastewater treatment facilities shall have influent screening. The Department may waive the requirement for influent screening for industrial treatment facilities. The design and location of the effluent flow monitoring system and effluent sampling point shall be to maximize confirmation that the effluent disposal permit limitations are being met. For new facilities, the flow monitoring location shall not be in a permit-entry-required confined space in accordance with 29 CFR 1910.146. For modifications of existing facilities consideration shall be given to the feasibility of compliance with 29 CFR 1910.146.

2. Each facility shall be fenced, or other means of controlling access by unauthorized persons shall be provided. The type of fencing or other means of controlling access shall be approved by the Department.

3. A weather durable sign, approved by the Department, with a twenty four (24) hour emergency telephone number, shall be located at a conspicuous point, typically located on the fence around the wastewater treatment facility, unless the wastewater treatment facility is located in a restricted access area.

4. All new wastewater treatment facilities shall be designed to be fully operational during flooding from a twenty five (25) year flood and shall be designed to be protected from physical damage from flooding from a one hundred (100) year flood. An all weather access road shall be provided to the wastewater treatment facility.

5. Facilities for the equalization of flows and/or mass loadings shall be provided for all wastewater treatment facilities which may be critically affected by surge or mass loadings, as determined by the Department.

6. For domestic wastewater treatment facilities, equipment shall be provided for flow equalization basins to maintain adequate mixing and aerobic conditions. Equalization or peak flow holding basins located in the collection system or at the treatment facility shall address issues to avoid odors at undesirable levels.

7. Aeration equipment for biological treatment shall be capable of maintaining a minimum of two (2.0) mg/l of dissolved oxygen in the mixed liquor at all times, unless the design specifically calls for a lower dissolved oxygen requirement. Thorough mixing of the mixed liquor shall be provided.

8. Aerobic digestors shall have sufficient aeration equipment provided to keep the solids in suspension and to maintain a dissolved oxygen between one (1.0) and two (2.0) mg/l, as a design condition.

9. All basins holding wastewater (treated or otherwise) shall be provided with a liner, designed with a permeability rate no greater than 10 ^-6 cm/sec, to prevent seepage. The Department may consider alternatives to this requirement for basins holding treated domestic wastewater such that there is not a concern about groundwater standards being exceeded. Consideration can be given to the characteristics of the wastewater and variability of the quality of the treated wastewater. Basins using soils with low permeability rates (e.g., clay) shall require appropriate documentation to demonstrate that the computed soil permeability rates of the liner are sufficiently low to preclude inappropriate seepage. Basins used for mixing (e.g., complete mix aeration basins) shall not be allowed to have earthen liners.

10. For land application facilities, all holding ponds, for treated wastewater, shall have a minimum storage capacity of seven (7) days at average daily design flow, unless there exists an approved, year round, backup (e.g., a separate NPDES permit), that could receive the treated wastewater for disposal if the land application site could not be utilized.

11. For chlorination systems, a minimum contact time of thirty (30) minutes at average daily flow and fifteen (15) minutes at peak design flow, is required. Industrial wastewater treatment facilities may be approved for lower contact times, if supported by proper documentation.

12. All return flows (e.g., drainage, supernatant, filtrate) generated at the wastewater treatment facility shall be returned to an appropriate location at the headworks of the wastewater treatment facility. The facility shall account for the quantity and quality of these flows.

13. Excluding pretreatment facilities, a continuous flow recorder shall be required where the design flow of the wastewater treatment facility exceeds fifty thousand (50,000) gallons per day.

14. Adequate water shall be provided at the wastewater treatment facility for maintenance. The water supply line shall be equipped with an approved reduced pressure backflow preventer if the source is potable water. If maintenance water is not potable, each spigot or tap shall be clearly marked non-potable (non-drinking) water.

15. All wastewater treatment facilities shall be provided with an alternative source of electric power to allow continuous operation of the appropriate units. Methods of providing alternative sources include:

a. Electric power shall be provided to the treatment works from two (2) separate utility substations;

b. An on site standby generator, either permanently installed or skid/trailer mounted, capable of supplying electrical power to all required components, based on the Reliability Classification of the wastewater treatment facility; or

c. Industrial facilities need to provide back up power as specified above unless the industrial facility can show that their processes stop in the event of a power outage and that enough storage is available until power is restored, so an overflow and/or a discharge other than treated wastewater shall not occur. Design calculations or other information shall be provided for justification.

16. Ultimate disposal of wastewater treatment facility residuals, to include sludge and bar screenings shall be identified and approved by the Department before a wastewater treatment facility can be permitted. Disposal shall be consistent with applicable Department regulations.

17. All wastewater treatment facilities shall be closed out within one hundred eighty (180) days in accordance with applicable regulations, when the facility is closed or the effluent disposal permit is inactivated, terminated or revoked, unless determined by the Department that a greater time is necessary. The closure plan must be approved by the Department as a prerequisite to closure. Conversion of existing wastewater treatment facilities to other basins such as equalization basins or storage basins shall only be considered by the Department for approval when explicitly identified in the applicable 208 Water Quality Management Plan. In such cases, sludge disposal must comply with Regulation Regulation 61-9.503 and Regulation 61-9.504.

18. All activated sludge wastewater treatment facilities shall have a means of solids or sludge removal.

19. Chlorine contact chambers following sequencing batch reactors shall be sized on the basis of the maximum discharge rate from the batch reactor, unless the effluent from the batch reactor is equalized to achieve a flow equal to the average daily flow.

20. All wastewater treatment facilities submitted to the Department for a construction permit shall include appropriate design calculations for all unit processes. The Department may require any additional supplemental information as needed.

G. Pump and Haul Operations.

1. Domestic Wastewater Pump and Haul Operations. The following criteria shall apply:

a. The Department may waive some or all of the criteria in subsection67.300.G.1.b if the project will address an existing water quality concern or problem.

b. Pump and haul operations shall not be used as a permanent means of wastewater handling. A pump and haul operation shall be allowed only for temporary sewer service, for a time period not to exceed thirty (30) days, unless otherwise approved by the Department. In addition, a pump and haul operation shall only be utilized for individual projects. Prior approval shall be obtained from the Department before initiating a pump and haul operation. Where there is no reasonable remedy for wastewater handling, pump and haul operations may be allowed in accordance with the following:

(1) The Department shall approve the entity responsible for pumping out, hauling, and disposing of the wastewater.

(2) All transporting of wastewater shall be in accordance with rules and regulations of the State Department of Transportation and other agencies as applicable.

(3) As a prerequisite for approval of a pump and haul operation, the permanent plan of wastewater handling and disposal shall be approved via the issuance of a construction permit by the Department. The completion of the permanent wastewater disposal system shall be properly bonded, or a financial assurance that the project shall be constructed.

(4) Weekly reports from the party responsible for the holding facility shall be submitted to the Department's local Environmental Quality Control District Office. The Department may specify a form to be used for reporting. Failure to submit these weekly reports or continuing the pump and haul operation beyond the approval date, without prior approval from the Department, may result in possible enforcement action by the Department. If the final disposal of this wastewater is at a wastewater treatment facility that is not owned by the party responsible for the pump and haul operation, a signed statement from the individual responsible for the wastewater treatment facility shall be included in the report. This statement shall give the time, date, and amount of wastewater received.

(5) The holding facility shall be inspected during each day's use by the responsible party, and pumped out as needed.

(6) A report containing the following information shall be submitted to the Department for approval:

(a) A discussion of the need for the pump and haul operation. Availability of sewer, NPDES permit options, or other options for the wastewater shall be discussed.

(b) A letter from the owner of the wastewater treatment facility receiving the wastewater shall be submitted agreeing to accept and treat the wastewater.

(c) The report shall discuss how spills and leaks shall be prevented during the transfer of wastewater and include best management practices.

(d) For private entities, some type of financial assurance (e.g., an escrow account) shall be established for payment to the party hauling and disposing of the wastewater (e.g., contract hauler). The sum to be placed in this escrow account shall be two (2) times the project cost for pumping and hauling the wastewater for thirty (30) days or other approved period of operation. If at any time the account is depleted to one third ( 1/3) the original amount and the pump and haul operation is still needed for more than ten (10) days, the owner of the project shall upon notice by the party responsible for this operation, bring the account up to two thirds ( 2/3) the original amount within five (5) days.

(e) The holding facility shall be sized to hold at least three (3) days of average daily flow from the project, based on the loadings as stated in 61-67 Appendix A. Consideration can be given to alternative storage capacity requirements for non-residential applications.

(f) The type of holding facility being proposed shall be approved by the Department, and shall be of watertight construction. The location of the holding facility shall be secured (e.g., fenced) to prevent access by unauthorized persons.

2. Industrial Wastewater Pump and Haul Operations. This applies to the storage of non-hazardous industrial and/or domestic wastewater generated by an industrial facility which is then hauled to a receiving facility at a rate of greater than one hundred (100) gallons per day or seven hundred (700) gallons per week or three thousand (3,000) gallons per month. One-time/intermittent operations or those on-site operations are exempt from these requirements. On a case-by-case basis, the Department may also consider other exemptions on the requirement to obtain pump and haul approval for certain process wastewaters. Intermittent is defined for this part as less than one shipment of wastewater per month. Not withstanding the need for Department approval, the facility shall retain hauling operations records for a period of two (2) years.

a. Pump and haul operations may be allowed in accordance with the following:

(1) Approval by the Department shall be required before a facility can have its wastewater hauled by a tanker truck or other vehicle to the receiving facility or when an approved facility proposes to change its method or location of its wastewater disposal.

(2) All transporting of wastewater shall be in accordance with rules and regulations of the State Department of Transportation and other agencies as applicable.

(3) A back up receiving facility or other contingency plan for the wastewater may be required, as determined by the Department.

(4) Pump and haul operations may not be approved unless the proposed off-site receiving facility has the capability to appropriately manage and treat the waste.

(5) A report containing the following information shall be submitted to the Department for approval:

(a) The name and location of the industrial facility, the current (if applicable) receiving facility, and the proposed receiving facility.

(b) A brief description of the type and amount of waste and how it is generated.

(c) A discussion of the need for the pump and haul operation. Availability of sewer, NPDES permit options, or other options for the wastewater shall be discussed. Proposed pump and haul operations that have a reasonably available sewer (including consideration for sewer and treatment capacity and capability) may be considered not suitable for approval. An engineering estimate of the annualized cost (including treatment, piping, transportation, operations, etc.) of the current and proposed disposal methods, including any possible capital costs, may be required by the Department.

(d) A letter from the owner of the receiving treatment facility agreeing to accept and treat the wastewater.

(e) The corresponding limitations page(s) from the proposed receiving facility's discharge or pretreatment permit.

(f) The capacity of the holding facility, type and amount of wastewater, compatibility of the wastewater with the holding facility material and holding times. Analytical data or other information may also be required as determined by the Department.

(g) A discussion of how spills and leaks shall be prevented during the transfer of wastewater, including best management practices.

(6) The Department may require the applicant to provide at least one alternate facility to receive the wastewater if there is a question of maintaining adequate capacity at the facility receiving the wastewater. A construction permit for the holding facility may be required by the Department (e.g., permanent holding facilities).

b. Permanent industrial pump and haul operations shall not be allowed where an industry cannot obtain or has been denied sewer service by the entity designated through the 208 planning process as being responsible for providing sewer service to the area where the industry will be or is located.

c. Except as given in subsection67.300.G.2.d. below, temporary pump and haul operations shall not be allowed when an industry has its local service disconnected because of violations of the local entity's industrial user permit or other violations.

d. When an industry has been cut off from sewer service, no additional wastewaters may be generated by the industry beyond the wastewater that was generated on the day of the cut off and the day after the cut off occurred. In these situations, the Department may approve temporary pump and haul for the wastewaters generated during those two (2) days and any contaminated storm water that will continue to occur up to final closure of the entire industrial facility.

e. When an industry has been cut off from sewer service because of violations of the local entity's industrial user permit or other violations, the industry must cease all manufacturing operations on the site within one (1) day after the cut off date unless a longer time period is allowed in writing by the Department. Additionally, an approvable shut down plan must be submitted to the Department within one (1) week of the sewer service cut off date. The shut down plan must include a wastewater facility closure plan for any wastewater facilities in accordance with SC Regulation Regulation 61-82.

H. Unit Contributory Loadings to All Domestic Wastewater Treatment Facilities. Refer to 61-67 Appendix A for the minimum design loadings that shall be utilized for all domestic wastewater treatment facilities and those industrial wastewater treatment facilities treating strictly domestic wastewater. These loadings shall be used in determining the average daily flow (ADF) for proposed sewer systems.

1. The loadings in 61-67 Appendix A may either be increased or decreased as determined by this Department.

2. A reduction in the loadings in 61-67 Appendix A may be granted in the following circumstances:

a. Consideration to other unit contributory loadings may be granted when properly substantiated by the consulting engineer in its engineering report and/or permit application.

b. For existing systems, a reduction may be granted to the wastewater treatment facility when supported with proper documentation. The proper documentation shall be continuously monitored flow at the wastewater treatment facility for several years, including dry and wet years as determined by rainfall data, unless flows are not representative, as determined by the Department. If approved, the reduction in the unit contributory loading shall be approved for all future projects discharging to the wastewater treatment facility (and would be used to revise the current level of remaining capacity). The decision to reduce the loadings shall be made by this Department on an individual treatment facility basis.

S.C. Code Regs. § 61-67.67.300

Amended by State Register Volume 39, Issue No. 06, eff. 6/26/2015.