Section 18 AAC 74.120 - Classification of water and wastewater systems(a) Water distribution and wastewater collection systems designated in 18 AAC 74.006 are classified as follows:(1) except as provided in (2) and (3) of this subsection, water distribution and wastewater collection systems are classified as follows: (A) systems with 15 to 500 service connections are classified as class 1;(B) systems with 501 to 5,000 service connections are classified as class 2;(C) systems with 5,001 to 15,000 service connections are classified as classified as class 3;(D) systems with more than 15,000 service connections are classified as class 4;(2) for water distribution systems, the following requirements also apply:(A) water distribution systems where water is circulated or heated to prevent freezing in the water distribution system will be classified at one class higher than the class determined under (1)(A) - (C) of this subsection;(B) water distribution systems with five or more pressure zones will be classified at one class higher than the class determined under (1)(A) - (C) of this subsection;(C) water distribution systems with five or more pressure zones and where water is circulated or heated to prevent freezing in the water distribution system will be classified at one class higher than the class determined under (1)(A) - (C) of this subsection;(3) for wastewater collection systems, the following requirements also apply: (A) wastewater collection systems where gravity is the only means of wastewater flow will be classified as class 1 systems, regardless of the number of service connections;(B) wastewater collection systems with 15 or more main line lift stations will be classified at one class higher than the class determined under (1)(A) - (C) of this subsection.(b) Water treatment and wastewater treatment systems designated in 18 AAC 74.006 are classified as follows: (1) wastewater treatment systems that score 1 - 30 points under (d) of this section, and where stabilization ponds without aeration are the only means of secondary treatment, are classified as wastewater stabilization pond systems;(2) water treatment and wastewater treatment systems, other than wastewater stabilization pond systems, are classified as set out in Table B of this subsection. TABLE B CLASSIFICATION RATING SYSTEM: TREATMENT SYSTEMS (By Range of Points) System Type 1 2 3 4 Wastewater Treatment System 1-30 31-55 56-75 76 and above Water Treatment System 1-30 31-55 56-75 76 and above (c) The department may, after considering advice of the board, modify the rating system in (a) and (b) of this section as applied to a particular system if the department finds that(1) unusual factors affect the complexity of unit processes, the quality of raw water sources, or the users of water downstream from wastewater system discharges; or(2) potential health hazards exist.(d) To classify wastewater treatment systems under (b) of this section, (1) the department will use the following point system:ItemPointsSize Peak day design capacity, gallons per day: less than 10,000 1 10,000 - 50,000 2 50,001 - 100,000 4 100,001 - 500,000 9 500,001 - 1,000,000 12 1,000,001 - 5,000,000 16 5,000,001 - 10,000,000 20 10,000,001 - 50,000,000 25 greater than 50,000,000 30 Pretreatment Influent pumping 2 Flow equalization basin 1 Manually cleaned screens 1 Mechanically cleaned screens 2 Fine screens, including microscreens 3 Comminutor, barminutor, grinders 2 Grit removal 2 Primary treatment Primary clarifiers 4 Primary clarifiers with chemical addition 7 Imhoff tank, or other method of combined sedimentation and digestion, other than a septic tank 3 Dissolved air flotation 16 Secondary Treatment Trickling filter without recirculation 5 Trickling filter with recirculation 8 Activated sludge: Oxidation ditch 8 Diffused or dispersed aeration 10 Pure oxygen 15 Sequencing batch reactor (SBR), intermittent cycle extended aeration system (ICEAS), or other batch treatment method 20 Additional points if an activated sludge plant is operated in high rate mode or contact stabilization mode 2 Rotating biological contactor 10 Activated bio-filter with aeration 10 Activated bio-filter without aeration 8 Stabilization ponds without aeration 5 Aerated lagoon 8 Secondary clarifiers 4 Secondary clarifiers with chemical addition 7 Advanced Waste Treatment Polishing pond or effluent flow equalization 2 Chemical and physical treatment without secondary treatment 20 Chemical and physical treatment following secondary treatment 15 Ion exchange 4 Granular media filtration 8 Membrane filtration, including reverse osmosis, microfiltration, ultrafiltration or nanofiltration 10 Membrane filtration, integrated system 12 Electrodialysis, electrodialysis reversal 10 Biological or combined chemical and biological nutrient removal 12 Nitrification by extended aeration only 2 Chemical precipitation of phosphorous 3 pH adjustment 3 Activated carbon columns or beds 8 In-plant Odor Control (maximum of 6 points in any combination) Biofilter 3 Adsorption with activated carbon or equal adsorbent 3 Wet scrubber 3 Thermal deactivation with catalytic process 6 Odor-reducing sprays 2 Sludge Thickening and Dewatering Sludge decant tank 2 Gravity thickener basin 3 Gravity belt thickener 4 Screw press 5 Centrifuge 6 Belt filter press, plate-and-frame press, or vacuum filter 8 Sludge bagger 3 Evaporative sludge drying by means of drying beds 2 Additional points if a polymer is added to sludge before the sludge is put in drying beds 3 Sludge Stabilization and Conditioning Unheated anaerobic digestion 8 Heated anaerobic digestion 10 Aerobic digestion 5 Wet oxidation 10 Chemical stabilization with lime 3 In-vessel composting, if controlled and operated by the operator as part of routine system operations 10 Static pile composting, if controlled and operated by the operator as part of routine system operations 5 Solids Disposal Incineration, if controlled and operated by the operator as part of routine system operations 12 Land application, if controlled and operated by the operator as part of routine system operations 5 Sludge lagoon 3 Off-site disposal 1 Disinfection Liquid and powdered hypochlorites 3 Additional points if hypochlorites are generated on-site 2 Gas chlorine 12 Chlor-alkali on-site generation 12 Chlorination using tablets 1 Ultraviolet light 3 Ozonation without pure oxygen 3 Ozonation with pure liquefied oxygen 4 Ozonation with on-site generation of pure oxygen 5 Dechlorination with gas 10 Dechlorination with chemical dechlorination agents other than gas 3 Dechlorination using tablets 1 Effluent Discharge Plant pumping of effluent 2 Effluent aeration 2 (2) for purposes of this subsection, community septic tanks will be considered part of the wastewater collection system, not a primary treatment method; and(3) nutrient removal utilizing biological or combined chemical and biological processes for advanced waste treatment include one or more of the following methods:(A) nitrification that utilizes those processes, if a facility nitrifies based solely on detention time or another extended aeration process, only the points for nitrification by extended aeration will be given;(e) To classify water treatment systems under (b) of this section,(1) the department will use the following point system:Item PointsSize Peak day design capacity, gallons per day: less than 10,000 1 10,000 - 50,000 2 50,001 - 100,000 4 100,001 - 500,000 9 500,001 - 1,000,000 12 1,000,001 - 5,000,000 16 5,000,001 - 10,000,000 20 10,000,001 - 50,000,000 25 greater than 50,000,000 30 Water Supply Source Groundwater 2 Groundwater under the direct influence of surface water 4 Surface water 6 Surface water maintaining filtration avoidance criteria under 18 AAC 80.620 8 Seawater 10 Purchased treated water 0 Raw water storage tank 3 Pretreatment Presedimentation basin 4 Hydrocyclone or similar sand separator device 2 Microscreen 3 Roughing filter: Cartridge filter 2 Non-backwashable strainer or filter 2 Gravel or rock filter 4 Backwashable granular media filter 8 Add-heat system to heat raw water 2 Adjustment and Corrosion Control pH adjustment 3 Corrosion inhibitor 3 Limestone or calcite contractor 2 Sequestration 3 Treatments Aeration: In-line venturi-type 1 Mechanical or diffused 3 Degasification 3 Ion exchange 4 Non-regenerated sorption processes, including activated alumina, modified activated alumina, and iron-based sorbents 3 On-site regeneration of sorption process media 10 Activated carbon, if not included as a bed layer in another filter: Activated carbon cartridge or bag filter 2 Powdered activated carbon treatment 4 Granular activated carbon contactors 4 On-site regeneration of activated carbon 16 Chemical oxidation: Hypochlorite solution 3 Gas chlorine 12 Potassium permanganate 4 Hydrogen peroxide 5 Ozonation without pure oxygen 3 Ozonation with pure liquefied oxygen 4 Ozonation with on-site generation of pure oxygen 5 Coagulation: Primary coagulant 5 Coagulant aid, flocculent, or filter aid 3 points for each chemical added, up to a maximum of 12 points Rapid mix units: Mechanical mixers 5 Injection mixers 3 In-line blender mixers 2 In-line static mixers 0 Flocculation tanks: Hydraulic flocculator 4 Mechanical flocculator 8 Sedimentation or clarification: Tube settlers 2 Inclined-plate, Lamella-type or equivalent 2 Horizontal flow conventional clarifier 4 Batch sedimentation 2 Adsorption clarifier 6 Up-flow solids contact 10 Dissolved air flotation 16 Combined rapid mix-coagulation-flocculation-sedimentation unit 20 Filtration: Cartridge or bag filter - single unit 2 Cartridge or bag filters - staged, multiple units 4 Slow sand 4 Granular media 8 Membrane filtration, including reverse osmosis, microfiltration, ultrafiltration, or nanofiltration 8 Membrane filtration, integrated system 12 Diatomaceous earth 12 Electrodialysis, electrodialysis reversal, distillation 10 Lime softening 16 Recarbonation 8 Fluoridation: Sodium fluoride saturator 2 Sodium silicofluoride 3 Hydrofluorosilicic acid 5 Disinfection: Liquid and powdered hypochlorites 3 Additional points if hypochlorites are generated on-site 2 Gas chlorine 12 Chlorination using tablets 1 Ammonia addition for chloramination: using liquid ammonia solution 3 using ammonia gas 12 Chlorine dioxide 8 Chlor-alkali on-site generation 12 Ozonation without pure oxygen 3 Ozonation with pure liquefied oxygen 4 Ozonation with on-site generation of pure oxygen 5 Ultraviolet light 2 Ultraviolet light, for the purposes of meeting required inactivation 4 Water storage tank, for the purpose of achieving contact time 3 Finished water storage tank, if the system serves fewer than 500 individuals people or 100 service connections, and the tank has a capacity of 1,000,000 gallons or more 3 the tank has a capacity of 50,000 - 999,999 gallons or more 2 the tank has a capacity of less than 50,000 gallons 1 Pressure tanks 0 On-site treatment of system sludge or backwash: Discharge to sewer or other off-site treatment 0 Discharge to on-site pond, septic tank, or lagoon 2 Mechanical dewatering 6 Filter backwash water or sludge supernatant recycling: groundwater source 2 surface water source 3 (2) for purposes of the point system set out in (1) of this subsection, the department will assign a point value to ozonation only once, even if ozonation is used to accomplish multiple water treatment objectives;(3) for purposes of the point system set out in (1) of this subsection, a system with a water storage tank for the purpose of achieving contact time and with a water storage tank for the purpose of storing finished water will only be assigned a point value for the water storage tank used for the purpose of achieving contact time.Eff. 8/21/78, Register 67; am 8/24/85, Register 95; am 1/18/2001, Register 157; am 12/3/2006, Register 180; am 11/21/2010, Register 196; am 11/26/2016, Register 220, January 2017Authority:AS 46.30.010
AS 46.30.080
AS 46.30.090