(A) Certain terms. For the purposes of this chapter, certain terms or words used are interpreted as follows: the words "shall" and "must" are mandatory and the words "should" and "may" are permissive. All distances specified in this chapter are horizontal distances unless otherwise specified.
(B) For the purpose of this chapter, the certain words and phrases are defined as follows:
ABSORPTION AREA. The parameter that is associated with the hydraulic acceptance of effluent. It is also commonly known as the infiltrative surface. The ABSORPTION AREA for a Mound System is the Original Soil below a Mound System that is designed to absorb Sewage tank effluent. The ABSORPTION AREA for Trenches, Seepage Beds, and At-Grade Systems is the soil area in contact with the part of the Distribution Medium that is designed and loaded to allow absorption of Sewage Tank Effluent. This includes both bottom and sidewall soil contact areas.
AGENCY. The Minnesota Pollution Control Agency (MPCA).
ALARM DEVICE. A device that alerts a system operator or system Owner of a component's status using a visual or audible device. An ALARM DEVICE can be either on Site or remotely located.
APPLICABLE REQUIREMENTS.
(a) This chapter; Minn. Rules Chapter 7082, and M.S. § 115.55; or
(b) In areas of the county without complying ordinances to regulate SSTS, the requirements in this chapter.
AS-BUILTS. Drawings and documentation specifying the final in-place location, size, and type of all system components. These records identify the results of materials testing and describe the conditions during construction. An AS-BUILT also contains a Certified statement.
ASTM. The American Society for Testing and Materials.
AT-GRADE SYSTEM. A pressurized soil treatment and dispersal system where Sewage tank effluent is dosed to an absorption bed that is constructed directly on Original Soil at the ground surface and covered by loamy soil materials.
BAFFLE. A device installed in a Septic Tank to retain solids and includes, but is not limited to, vented sanitary tees with submerged pipes and Effluent Screens.
BEDROCK. Geologic layers, of which greater than 50% by volume consists of unweathered in-place consolidated rock or rock fragments. BEDROCK also means weathered in-place rock which cannot be hand augered or penetrated with a knife blade in a soil pit.
BEDROOM. For the sole purpose of estimating design flows from Dwellings, an area that is:
(a) A room designed or used for sleeping; or
(b) A room or area of a Dwelling that has a minimum floor area of 70 square feet with access gained from the living area or living area hallway. Architectural features that affect the use as a Bedroom under this item may be considered in making the Bedroom determination.
BIOCHEMICAL OXYGEN DEMAND or BOD. The measure of the amount of oxygen required by bacteria while stabilizing, digesting, or treating biodegradable organic matter under aerobic conditions over a five-day incubation period, commonly expressed in milligrams per liter (mg/L).
BUILDING. Any structure used or intended for supporting or sheltering any use or occupancy.
BUILDING SEWER. The part of the drainage system which extends from the end of the Building drain and conveys its discharge to a subsurface Sewage treatment system.
CARBONACEOUS BIOCHEMICAL OXYGEN DEMAND or CBOD5. The measure of the amount of oxygen required by bacteria while stabilizing, digesting, or treating organic matter under aerobic conditions over a five-day incubation period while in the presence of a chemical inhibitor to block nitrification. CBOD5 is commonly expressed in milligrams per liter (mg/L).
CERTIFICATE OF COMPLIANCE. A document, written after a Compliance Inspection, certifying that a system is in compliance with applicable requirements at the time of the inspection.
CERTIFIED. An individual is included on the Agency's SSTS certification list and is qualified to design, install, maintain, repair, pump, operate, or inspect an SSTS as appropriate with the individual's qualifications. A CERTIFIED individual who is working under a license is subject to the obligations of the license. CERTIFIED individuals were previously known as registered professionals.
CERTIFIED STATEMENT. A statement signed by a Certified individual, apprentice, or qualified employee under Minn. Rules Chapter 7083 certifying that the licensed business or qualified employee completed the work in accordance with applicable requirements.
CESSPOOL. An underground pit, receptacle, or seepage tank that receives Sewage and leaches Sewage into the surrounding soil, Bedrock, or other soil materials. CESSPOOLS include Sewage tanks that were designed to be Watertight, but subsequently leak below the designed operating depth.
CLEAN SAND. A soil fill material required to be used in mounds. The standards for CLEAN SAND are outlined in § 52.17(C)(10).
COMMISSIONER. The Commissioner of the Minnesota Pollution Control Agency.
COMPLIANCE INSPECTION. An evaluation, investigation, inspection, or other such process for the purpose of issuing a Certificate of Compliance or Notice of Noncompliance.
CONTOUR LOADING RATE. The amount of effluent loaded to the soil per length of the dispersal unit or units along the single hillslope along the contour. The Contour Loading Rate is determined on the relationship between the vertical and horizontal water movement in soil and is based on the permeability difference between the Absorption Area and any deeper horizons, the depth between the Absorption Area and the change in permeability; and the land Slope.
DEPARTMENT. The Washington County Department of Public Health and Environment.
DISINFECTION. The process of destroying or inactivating pathogenic microorganisms in Sewage to render them noninfectious.
DISTINCT. A soil color that is not faint as described in this section.
DISTRIBUTION BOX. A device intended to distribute Sewage tank effluent concurrently and equally by gravity to multiple segments of a Soil Dispersal System.
DISTRIBUTION DEVICE. A device used to receive and transfer effluent from Supply Pipes to Distribution Pipes or downslope Supply Pipes, or both. These devices include, but are not limited to, Drop Boxes, Valve Boxes, Distribution Boxes, or manifolds.
DISTRIBUTION MEDIUM. The material used to provide void space in a dispersal component, through which effluent flows and is stored prior to infiltration. DISTRIBUTION MEDIA includes, but is not limited to, drainfield rock, polystyrene beads, chambers, and gravelless pipe.
DISTRIBUTION PIPES. Perforated pipes that distribute effluent within a Distribution Medium.
DNR. The Minnesota Department of Natural Resources.
DOMESTIC WASTE. Liquid waste produced by toilets, bathing, laundry, culinary operations, and the floor drains associated with these sources, and includes household cleaners, medications, and other constituents in Sewage restricted to amounts normally used for domestic purposes. DOMESTIC WASTE has a Biochemical Oxygen Demand of 175 mg/L or less, a total suspended solids level of 65 mg/L or less, an oil and grease concentration of 25 mg/L or less and no Hazardous Wastes. Animal waste and commercial or industrial waste are not considered Domestic Waste.
DRIP DISPERSAL SYSTEM. A small diameter pressurized wastewater distribution system in which the treated effluent is distributed under pressure to the infiltrative surface via drip tubing and enters the receiving environment.
DROP BOX. A Distribution Device used for the serial gravity application of Sewage tank effluent to a Soil Dispersal System.
DWELLING. Any Building with provision for living, sanitary, and sleeping facilities.
EFFLUENT SCREEN. A device installed on the outlet piping of a Septic Tank for the purpose of retaining solids of a specific size.
EPA. The United States Environmental Protection Agency.
EVEN DISTRIBUTION. A method that, upon activation of the SSTS, reliably distributes effluent over the entire required Absorption Area.
EXISTING SYSTEM. A system that has been previously inspected and approved by the Department or local unit of government during installation. In addition, all operating systems installed before the adoption of this chapter are considered Existing Systems.
FAINT. A soil color:
(a) With the same hue as another soil color but that varies from the other color by two or less units of value and not more than one unit of chroma;
(b) That differs from another soil color by one hue and by one or less units of value and not more than one unit of chroma; or
(c) That differs from another soil color by two units of hue with the same value or chroma.
FECAL COLIFORM or FC. For the purposes of this chapter, means bacteria common to the digestive systems of humans that are cultured in standard tests. Counts of these organisms are typically used to indicate potential contamination from Sewage or to describe a level of Disinfection, generally expressed in colonies per 100 mL.
FINE SAND. A Soil Texture, as described in the Field Book for Describing and Sampling Soils, which is incorporated by reference in this section where more than 50% of the Sand has a particle size range of 0.05 millimeters, sieve size of 270, to 0.25 millimeters, sieve size 60.
FLOOD FRINGE. That portion of the Floodplain outside of the Floodway. Flood fringe is in the Flood Insurance Study for Washington County and identified on the Flood Boundary and Floodway Maps as Floodway fringe.
FLOODPLAIN. The area covered by a 100-year flood event along lakes, rivers, and streams as published in technical studies by local, state, and federal agencies, or in the absent of these studies, estimates of the 100-year flood boundaries and elevations as developed according to Washington County.
FLOODWAY. The bed of a wetland or lake, the channel of a watercourse, and those portions of the adjoining Floodplain that are reasonably required to carry the regional flood discharge.
FLOW MEASUREMENT. Any method to accurately measure water or Sewage flow, including, but not limited to, water meters, event counters, running time clocks, or electronically controlled dosing.
GEOMORPHIC DESCRIPTION. The identification of the landscape, landform, and surface morphometry of the proposed area of the soil treatment and dispersal system as described in the Field Book for Describing and Sampling Soils: Version 2.0 (2002). developed by the National Soil Survey Center and Natural Resources Conservation Service of the United States Department of Agriculture. The field book is incorporated by reference, is not subject to frequent change, and is available through the Minitex interlibrary loan system.
GRAYWATER. Sewage that does not contain Toilet Wastes. Liquid wastes from a Dwelling or Other Establishment produced by bathing, laundry, culinary operation, and from floor drains associated with these sources are considered GRAYWATER.
GRAYWATER SYSTEM. A system that receives, treats, and disperses only Graywater or other similar system as designated by the commissioner.
GROUNDWATER MOUND. The rise in height of the Periodically Saturated Soil or regional water table caused by the addition of Sewage effluent from a subsurface Sewage treatment system into the soil.
HAZARDOUS WASTE. Any substance that, when discarded, meets the definition of Hazardous Waste in M.S. § 116.06, subd. 31, Minn. Rules Chapter 7045, or Washington County Ordinance No. 166.
HOLDING TANK. A tank for storage of Sewage until it can be transported to a point of treatment and dispersal. Holding tanks are considered a septic system tank under M.S. § 115.55.
INDIVIDUAL SUBSURFACE SEWAGE TREATMENT SYSTEM or ISTS. An individual Sewage treatment system or part thereof, as set forth in M.S. §§ 115.03 and 115.55, that employs Sewage tanks or other treatment devices with final discharge into the soil below the natural soil elevation or elevated final grade that are designed to receive a Sewage design flow of 5,000 gallons per day or less. ISTS includes the Holding Tanks and privies, but does not include any Pump Tanks used in a Sewage collection system. ISTS does not include Building sewers or other components regulated under Minn. Rules Chapter 4715, or Sewage collection systems.
INNER WELLHEAD MANAGEMENT ZONE. The drinking water supply management area for a public water supply well that does not have a delineated Wellhead Protection Area approved by the Department of Health under Minn. Rules Chapter 4720, § 4720.5330.
INVERT. The lowest point of a channel inside a pipe.
IMMINENT THREAT TO PUBLIC HEALTH OR SAFETY. An ISTS which discharges Sewage or Sewage effluent to the ground surface, drainage system, ditches, or storm water drains or directly to surface water; or causes a reoccurring Sewage backup into a Dwelling or Other Establishment; or has an electrical hazard; or includes a Sewage tank with an unsecured, damaged, or weak maintenance hole cover; or an ISTS that has received Hazardous Waste, or other safety or health hazard as determined by those authorized in Minn. Rules Chapter 7083.
ISTS FAILING TO PROTECT GROUNDWATER. A Seepage Pit, Cesspool, drywell, leaching pit or Other Pit; or an ISTS that has less than the required Vertical Separation distance as described in § 52.04(C)(4) and (5); or an ISTS not abandoned in accordance with § 52.23; or any other threat to groundwater quality as determined by those authorized in Minn. Rules Chapter 7083.
LIQUID CAPACITY. The liquid volume of a Sewage tank below the Invert of the outlet pipe or, for Holding Tanks and Pump Tanks, the liquid volume below the Invert of the inlet.
LONG-TERM SEWAGE TREATMENT. Enough space on a Lot for two Type I or Type II soil treatment and dispersal areas.
LOT. A parcel of land designated by metes and bounds, registered land survey, plat or other means, and which description is either recorded in the Office of the Washington County Recorder or Registrar of Titles or used by the County Treasurer or County Assessor to separate such parcel from other lands for tax purposes.
MANAGEMENT PLAN. A plan that requires the periodic examination, adjustment, testing, and other operational requirements to meet system performance expectations, including a planned course of action in the event a system does not meet performance expectations.
MATRIX. The majority of the color in a soil horizon, as described in the Field Book for Describing and Sampling Soils, which is incorporated by reference in this section.
MIDSIZED SUBSURFACE SEWAGE TREATMENT SYSTEM or MSTS. An individual Sewage treatment system, or part thereof, as set forth in M.S. §§ 115.03 and 115.55. that employs Sewage tanks or other treatment devices with final discharge into the soil below the natural soil elevation or elevated final grade and that is designed to receive Sewage from Dwellings or Other Establishments with a design flow of greater than 5,000 gallons per day to 10,000 gallons per day. Design flows must be determined by § 52.12(G). MSTS also includes on-Lot Septic Tanks, Holding Tanks, and privies, but does not include any Pump Tanks used in a Sewage collection system. MSTS does not include those components defined as plumbing under Minn. Rules Chapter 4715 or Sewage collection systems.
MOTTLES. The minority of the variegated colors in a soil horizon, as described in the Field Book for Describing and Sampling Soils, which is incorporated by reference in this section.
MOUND SYSTEM. A soil treatment and dispersal system designed and installed such that all of the infiltrative surface is installed above grade, using Clean Sand between the bottom of the infiltrative surface and the original ground elevation, utilizing Pressure Distribution, and capped with suitable soil material to stabilize the surface and encourage vegetative growth.
MPCA. The Minnesota Pollution Control Agency.
NEW CONSTRUCTION. Installing or constructing a new ISTS or altering, extending, or adding capacity to an Existing System.
NOTICE OF NONCOMPLIANCE. A document written and signed by a Certified inspector after a Compliance Inspection that gives notice that an ISTS is not in compliance with this chapter.
NPDES PERMIT. A National Pollutant Discharge Elimination System Permit issued by the MPCA.
O&G. Oil and grease, a component of Sewage typically originating from foodstuff such as animal fats or vegetable oils or consisting of compounds of alcohol or glycerol with fatty acids such as soaps and lotions, typically expressed in mg/L (also known as FOG, or fats, oil, and grease).
ORDINARY HIGH WATER LEVEL. The boundary of water basins, watercourses, Public Waters, and Public Waters wetlands, and:
(a) The ORDINARY HIGH WATER LEVEL is an elevation delineating the highest water level that has been maintained for a sufficient period of time to leave evidence upon the landscape, commonly the point where the natural vegetation changes from predominantly aquatic to predominantly terrestrial;
(b) For watercourses, the ORDINARY HIGH WATER LEVEL is the elevation of the top of the bank of the channel; and
(c) For reservoirs and flowages, the ORDINARY HIGH WATER LEVEL is the operating elevation of the normal summer pool.
ORIGINAL SOIL. Naturally occurring soil that has not been cut, filled, moved, smeared, compacted, altered, or manipulated to the degree that the loading rate must be reduced from that associated with natural soil conditions.
OTHER ESTABLISHMENT. Any public or private structure other than a Dwelling that generates Sewage that discharges into an ISTS or MSTS.
OTHER PIT. Any pit or other device designed to leach Sewage effluent that is greater than 30 inches in height or has a bottom area loading rate of Sewage greater than two gallons per square foot per day.
OWNER. Any person having possession of, control over, or title to property with an ISTS.
PARENT MATERIAL. The unconsolidated and chemically weathered geologic mineral or organic matter from which soils are developed by soil forming processes.
PERCOLATION RATE. The rate of a drop of water infiltrating into a test hole as specified in § 52.09(G)(2).
PERIODICALLY SATURATED SOIL. The highest elevation in the soil that is in a reduced chemical state due to soil pores filled or nearly filled with water causing anaerobic conditions. PERIODICALLY SATURATED SOIL is determined by the presence of Redoximorphic Features in conjunction with other established indicators as specified in § 52.09.(F)(5) or (6), or determined by other scientifically established technical methods or empirical field measurements acceptable to the local unit of government in consultation with the Department or the commissioner.
PERMIT. A Building, construction, sanitary, planning, zoning or other such Permit issued for New Construction, Replacement, repair, alteration, or extension of a subsurface Sewage treatment system. PERMIT also means a Permit issued for the addition of a Bedroom or bathroom on property served by a subsurface Sewage treatment system.
PERMITTEE. A person who is named on a Permit issued pursuant to these regulations.
PLASTIC LIMIT. A soil moisture content above which manipulation will cause compaction or smearing. The PLASTIC LIMIT can be measured by American Society for Testing and Materials, Standard Test Methods for Liquid Limit, Plastic Limit, and Plasticity Index of Soils, ASTM D4318 (2005). The standard is incorporated by reference, is available through the Minitex interlibrary loan system, and is not subject to frequent change.
PRESSURE DISTRIBUTION. A network of Distribution Pipes in which effluent is forced through orifices under pressure.
PRIVY. An aboveground structure with an underground cavity meeting the requirements of § 52.18(D) that is used for the storage or treatment and dispersal of Toilet Wastes, excluding water for flushing and Graywater. A PRIVY also means a nondwelling structure containing a Toilet Waste treatment device.
PROPRIETARY PRODUCT. A Sewage treatment or distribution technology method, or material subject to a patent or trademark.
PUBLIC DOMAIN TECHNOLOGY. A Sewage treatment or distribution technology, method, or material not subject to a patent or trademark.
PUBLIC WATERS. Any Public Waters or wetlands defined in M.S. § 103G.005. subd. 15, or identified as Public Waters or wetlands by the inventory prepared according to M.S. § 103G.201.
PUMP TANK. A tank or separate compartment following the Sewage tank that serves as a reservoir for a pump. A separate tank used as a Pump Tank is considered a septic system tank under M.S. § 115.55, subd. 1, paragraph (o).
REDOXIMORPHIC FEATURES.
(a) A color pattern in soil, formed by oxidation and reduction of iron and manganese in saturated soil coupled with their removal, translocation, or accrual, which results in the loss (depletion) or gain (concentration) of mineral compounds compared to the Matrix color; or
(b) A soil Matrix color controlled by the presence of ferrous iron. REDOXIMORPHIC FEATURES are described in § 52.09(F)(5).
REPLACEMENT. The removal or discontinued use of any major portion of an ISTS and reinstallation of that portion of the system, such as reinstallation of a new Sewage tank, Holding Tank, Pump Tank, Privy, or Soil Dispersal System.
SDS PERMIT. A State Disposal System Permit issued by the MPCA.
SAND. A Sand Soil Texture, as described in the Field Book for Describing and Sampling Soils, which is incorporated by reference in this section.
SEEPAGE BED. A soil treatment and dispersal system, the absorption width o which is greater than three feet but no greater than 25 feet.
SEEPAGE PIT. An underground pit that receives Sewage tank effluent and from which the liquid seeps into the surrounding soil.
SEPTAGE. Solids and liquids removed from an SSTS and includes solids and liquids from Cesspools, Seepage Pits, Other Pits, or similar systems or devices that receive Sewage. SEPTAGE also includes solids and liquids that are removed from portable, incinerating, Composting, holding, or other toilets. Waste from Type III marine sanitation devices, as defined in 33 C.F.R. § 159.3, and material that has come into contact with untreated Sewage within the past 12 months is also considered SEPTAGE.
SEPTIC TANK. Any Watertight, covered receptacle that is designed and constructed to receive the discharge of Sewage from a Building sewer or preceding tank, stores liquids for a detention period that provides separation of solids from liquid and digestion of organic matter, and allows the effluent to discharge to a succeeding tank, treatment device, or Soil Dispersal Area.
SERIAL DISTRIBUTION. Distribution of Sewage tank effluent by gravity flow that progressively loads one section of a soil treatment and dispersal system to a predetermined level before overflowing to the succeeding section and does not place a dynamic head on the lower section of the soil treatment and dispersal system. The Distribution Medium is allowed to serve as a conveyance medium to the next section.
SETBACK. A separation distance measured horizontally.
SEWAGE. Waste produced by toilets, bathing, laundry, culinary operations, and the floor drains associated with these sources, and includes household cleaners, medications, and other constituents in Sewage restricted to amounts normally used for domestic purposes.
SEWAGE FLOW. Flow as determined by measurement of actual water measurement; or, if actual measurements are not available, by the best available data provided.
SEWAGE TANK. A receptacle used in the containment or treatment of Sewage and includes, but is not limited to, Septic Tanks, aerobic tanks, Pump Tanks, and Holding Tanks. Requirements for Sewage tanks are described in § 52.13. SEWAGE TANKS are considered a septic system in M.S.§ 115.55, subd. 1, paragraph (o).
SEWAGE TANK EFFLUENT. The liquid that flows from a Septic Tank or other treatment device.
SITE. The area required for the proper location of the soil treatment system.
SLOPE. The vertical rise or fall divided by the horizontal distance, expressed as a percentage.
SOIL DISPERSAL AREA. The area required for the Soil Dispersal System, including space between individual units or zones.
SOIL DISPERSAL SYSTEM. A system where Sewage effluent is dispersed into the soil for treatment by absorption and filtration and includes, but is not limited to, Trenches, Seepage Beds, At-Grade Systems, Mound Systems and Drip Dispersal Systems.
SOIL TEXTURE. The soil particle size classification and particle size distribution as specified in the Field Book for Describing and Sampling Soils, incorporated by reference in this section.
SUBSOIL. A soil layer that has a moist color value of 3.5 or greater and has undergone weathering and soil formation processes.
SUBSURFACE SEWAGE TREATMENT SYSTEM or SSTS. Either an Individual Subsurface Sewage Treatment System as defined in this section or a Midsized Subsurface Sewage Treatment System as defined in this section, as applicable.
SUPPLY PIPE. A nonperforated pipe, the purpose of which is to transport Sewage tank effluent.
SYSTEMS IN SHORELAND AREAS OR WELLHEAD PROTECTION AREAS OR SYSTEMS SERVING FOOD, BEVERAGE, OR LODGING ESTABLISHMENTS, or SWF. The following three categories:
(a) SSTS constructed in shoreland areas where land adjacent to Public Waters has been designated and delineated as shoreland in Chapter Six of the Washington County Development Code:
(b) SSTS constructed in Wellhead Protection Areas regulated under M.S. Chapter 103I; and
(c) SSTS serving food, beverage, and lodging establishments that are required to obtain a licenses under M.S. § 157.16,subd. 1, and Washington County Ordinance No. 145 or 146, and includes manufactured home parks and recreational camping areas licensed according to M.S. Chapter 327 and Washington County Ordinance No. 147.
TEN-YEAR FLOOD. The flood which can be expected to occur, on an average of once in ten years, or the elevation to which flood waters have a ten percent chance of rising in any given year.
TN. Total nitrogen, which is the measure of the complete nitrogen content in wastewater, including nitrate (N03), nitrite (NO2), ammonia (NH3), and organic nitrogen, expressed as mg/L.
TOILET WASTE. Waste commonly disposed of in toilets, including fecal matter: urine, toilet paper, and water used for flushing.
TOILET WASTE TREATMENT DEVICES. Other Toilet Waste apparatuses including incinerating, Composting, biological, chemical, recirculating, or holding toilets or portable restrooms.
TOPSOIL. The natural, in-place organically enriched soil layer with a color value one less than 3.5.
TOPSOIL BORROW. A loamy soil material having:
(a) Less than 5% material larger than two millimeters, No. 10 sieve;
(b) No material larger than 2.5 centimeters;
(c) A moist color value of less than 3.5; and
(d) Adequate nutrients and pH to sustain healthy plant growth.
TOTAL SUSPENDED SOLIDS or TSS. Solids that are in suspension in water and that are removable by laboratory filtering, expressed as mg/L.
TP. Total phosphorus, which is the sum of all forms of phosphorus in effluent, expressed in mg/L.
TRENCH. A soil treatment and dispersal system, the absorption width of which is 36 inches or less.
VALVE BOX. A Watertight structure designed for alternate distribution of Sewage tank effluent to segments of a soil treatment system.
VERTICAL SEPARATION. The vertical measurement of unsaturated soil or Sand between the bottom of the Distribution Medium and the Periodically Saturated Soil level or Bedrock.
WATERTIGHT. Constructed so that no liquid can get into or out of a device except through designed inlets and outlets.
WELL CAPTURE ZONE. The surface and subsurface area that supplies water to a water supply well.
WELLHEAD PROTECTION AREA. The surface and subsurface area surrounding a well or well field that supplies a public water system, through which contaminants are likely to move toward and reach the well field as regulated under Minn. Rules Chapter 4720. For the purposes of this chapter, WELLHEAD PROTECTION AREA is that area bounded by the drinking water supply management area as regulated under Minn. Rules Chapter 4720.