(A) Definitions. For the purpose of this section, the following definitions shall apply unless the context clearly indicates or requires a different meaning.
(1) LOW PRESSURE SEWER SYSTEM. An alternative to a conventional gravity collector sewer system that relies on individual grinder pumps to deliver wastewater from buildings to a system of pressurized small diameter pipes that serve an area of the municipality. The system is typically used where gravity sewers are not cost effective and/or not feasible due to topography, excessive rock or other reason.
(2) GRINDER PUMP. Any electric motor-driven, submersible, centrifugal pump capable of macerating all material found in normal domestic sanitary sewage, including reasonable amounts of objects such as plastics, sanitary napkins, disposable diapers, rubber and the like, to a fine slurry and pumping this material through a small diameter discharge. Grinder pumps can be used as one component of an area-wide low pressure sewer system or to deliver wastewater from a single building to a gravity sewer system. In either case, the property owner's system will include the low pressure lateral from the pump to the city's limit of responsibility for the publicly owned sewer system.
(B) General. Low-pressure systems will only be considered in areas where conventional sanitary sewer facility construction is not feasible.
(C) Approval.
(1) Approval of low-pressure sewer systems will be evaluated on a case-by-case basis and will only be allowed with prior written approval from the Board of Public Works and Safety. At the discretion of the Board, a lift station may be required in lieu of a low pressure system.
(2) Property owner shall provide a record drawing showing the location of the building being served by the grinder pump, the grinder pump, electrical connection, lateral from building to grinder pump, lateral from grinder pump to common force main, shutoff valve, property line and driveway. The record drawing shall include a minimum of two dimensions to each the grinder pump and shutoff valve. Dimensions may be measured from building comers, property lines, electrical connection, or driveways. Example record drawings are available from the city.
(3) After installation of the grinder pump, the Wastewater Department will perform an inspection and complete a Sanitary Sewer Grinder Pump Inspection Report.
(D) Responsibility.
(1) The city will only be responsible for the operation and maintenance of the common force main in city property, right of way, or easement and the portion of the lateral from the common force main to, and including, the shutoff valve.
(2) The property owner shall be responsible for all piping, pumping equipment, and appurtenances between the building and the shutoff valve.
(3) The property owner shall maintain electrical service to the grinder pump system at all times.
(4) Any property owner with a grinder pump shall grant the city an easement for installation of the common force main if needed.
(E) Connections to grinder pump units.
(1) No more than one building will be permitted to connect to a grinder pump unit.
(2) Common grinder pumps for one building with multiple residential units are also prohibited.
(3) The intent is to have individual residential units be served by individual grinder pump units.
(4) Industrial facilities will be handled on a case-by-case basis.
(5) Flows to the grinder pump unit shall be wastewater sources only. Clear water discharges including, but not limited to, downspouts, sump pumps, perimeter drains and footing drains shall not flow to the sanitary sewer.
(F) Grinder pump equipment.
(1) Grinder pump pumping capacity shall be no greater than 15 gallons per minute (gpm).
(2) Grinder pump equipment shall be purchased by the property owner. Grinder pump equipment package may be purchased from the city for a discounted rate.
(3) All grinder pump equipment shall include a minimum two year warranty from the pump manufacturer. The warranty period shall start on the date of pump startup.
(G) Grinder pump installation.
(1) The grinder pump shall be installed so that the top of the grinder pump basin is above the 100-year flood elevation at the property.
(2) Locator wire shall be installed on the lateral from the grinder pump to the common force main.
(3) Grinder pumps shall be installed in accordance with detail drawings provided by the city.
(Ord. 2016-10, passed 9-6-2016)