Schedule 1 System Design Requirements for New Conventional On-Site Effluent Treatment Systems to Meet Minimum Requirements for Permitted Activities

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1 Environment Bay of Plenty On-Site Effluent Treatment Schedule 1 Schedule 1 System Design Requirements for New Conventional On-Site Effluent Treatment Systems to Meet Minimum Requirements for Permitted Activities This schedule specifies various design options for on-site effluent treatment systems which meet the minimum requirements for permitted activities. For new subdivisions, the overall lot (section) size must take into account the area required for the house, garage, drive, hard surface areas (paths, out buildings), garden areas, plus the treatment area, required to accommodate the initial soakage field system plus reserve area and incorporate buffer clearances and setbacks required by the district plan. For existing subdivided development, the selection and design of the pre-treatment and soakage field system may be constrained by the available space on the lot (section) in which to locate the treatment area. In accordance with Rule 3 of the plan, new systems to be installed after the On-Site Effluent Treatment becomes operative are permitted activities only if, among other requirements stated in the rule, the system meets certain minimum design standards as specified in the following tables. Advisory Notes: 1 The conventional on-site wastewater pre-treatment unit must be sized according to the formulae provided in Table 5. 2 Conventional on-site effluent treatment systems with a total score between 1 and 4 (inclusive) from Table 6 are permitted activities, provided that the minimum requirements for trench length set out in Table 7 are met (including the reserve area requirement that shall be kept free from inappropriate development (buildings and impervious surfaces). 3 Conventional on-site effluent treatment systems with a total score of 5 or more from Table 6 are discretionary activities, unless the systems can be modified in accordance with the modification factors set out in Table 8 and thereby meet the minimum requirements for permitted activities. 4 Where permeability testing is to be undertaken to assist in confirmation of soil category for design purposes, then such testing shall be carried out in accordance with AS/NZ 1547:2000, Soil Permeability Measurement Constant-head Test. 89

2 Schedule 1 On-Site Effluent Treatment Environment Bay of Plenty Table 5 Septic Tank Capacities A: Number of Bedrooms Minimum Tank Capacity/Size (Litres) 1 to to Notes: 1. Effluent outlet filter installation is the preferred septic tank design approach for all conventional on-site effluent treatment systems 2. As volume measured from outlet invert to septic tank base (i.e. liquid volume), if a garbage grinder is installed in a conventional effluent system, an effluent outlet filter should be installed at the outlet of the septic tank to protect the soakage field, and the tank size should be increased to the larger size to accommodate the extra solids produced. B: Households (Blocks of Units/Flats) (Refer to Table 9) For 10 persons or more the capacity (C) may be determined by the formula C = (P x A) litres where P = the number of persons to be served and A = the daily wastewater flow allowance in litres/person/day C: Institutions (Refer to Table 9) For flows greater than 700 litres per day the capacity (C) may be determined by the formulae as set out below: Motels/Hotels - without restaurant C = (P x A) litres - with restaurant C = (P x A) litres Community halls, schools, rural factories, shopping centres, camping grounds C = (P x A) litres where P = the number of persons to be served and A = the daily wastewater flow allowance in litres per person per day 90

3 Environment Bay of Plenty On-Site Effluent Treatment Schedule 1 Table 6 Factors Restricting Choice of Conventional On-Site Effluent Treatment System Select one item from each of numbered sections below and put the score in 1st score column to find out first score. On-site effluent treatment systems with a total score between 1 and 4 (inclusive) from Table 6 are permitted activities provided they meet the requirements of Rule 3 of the Plan. On-site effluent treatment systems with a score of 5 or more from Table 6 are discretionary activities unless the systems can be modified in accordance with the modification factors set out in Table 8. 1 Pre-Treatment Level (Maintenance access should be provided) (a) Single stage septic tank with approved effluent outlet filter (b) Two stage septic tank and approved effluent outlet filter (c) Greywater only Factor st Score 2 nd Score (if necessary) 2 Depth to Highest Groundwater Table Conventional On-Site Effluent Systems below bottom of soakage field land treatment area 4 greater than 1500 millimetres between millimetres between millimetres between millimetres Soil Category (Refer to Table 10) 1 gravel, coarse sand; rapid draining; 2 coarse to medium sand; free draining; 3 medium-fine and loamy sand; good drainage; 4 sandy loam, loam and silt loam; moderate drainage; 5 sandy clay-loam, clay-loam and silty clayloam; moderate to slow drainage. 6 sandy clay, non-swelling clay and silty clay; slow drainage. 7 swelling clay, grey clay, hardpan; poorly or non-draining See Definition of Terms for definition of Treatment Area 91

4 Schedule 1 On-Site Effluent Treatment Environment Bay of Plenty 4 Restrictive Soil Horizon 5 (barrier to soil soakage) Restrictive drainage soil horizon within 2 metres of soil surface. Restrictive drainage soil horizon deeper than 2 metres of soil surface Slope less than 15 percent slope (8.5 o ) greater than 15% (8.5 o ) 6 Barrier to Horizontal Soil Soakage Within 3 metres (For example vertical cuttings, retaining walls, building walls etc. in the soil profile) greater than 3 metres and greater than 45 degrees from the toe of a wall/embankment less than 3 metres or less than 45 degrees from the toe of the wall/embankment Proximity to Surface Water (including ephemeral) or Water Supply Bore (i) Greater than or equal to 40 metres (ii) Between metres (iii) Less than 20 metres TOTAL SCORE 5 A restrictive soil horizon may be a change in soil textural class or some other change which severely reduces drainage. 92

5 Environment Bay of Plenty On-Site Effluent Treatment Schedule 1 Table 7 Effluent Treatment Trench Length Required (in metres) for Discharge Volumes of up to 2 cubic metres per day to Standard Trenches Soil Category 1 (LPED) Average daily flow (L) 2 Number of Bedrooms Min. Trench Length (metres) Req. Area Req. (metres 2 ) incl. Reserve Area Min. Trench Length (metres) Req. Area Req. (metres 2 ) incl. Reserve Area Min. Trench Length (metres) Req. Area Req. (metres 2 ) incl. Reserve Area Min. Trench Length (metres) Req. Area Req. (metres 2 ) incl. Reserve Area Min. Trench Length (metres) Req. Area Req. (metres 2 ) incl. Reserve Area Up to Up to to More than or more Resource consent is required for discharges >2m 3 /day Advisory Notes: 1 For Category 1 soils a low pressure effluent distribution system (LPED) must be used. This system utilises pump dosed loading into a perforated small diameter pipe inserted within draincoil (refer Figure 4). The LPED dosing system requires careful design to ensure even distribution throughout the full trench system. Automatic sequencing valves may be used in preference to pressure manifolds. Pressure dosing systems must incorporate an alarm/warning system on the pump unit to detect failure of the system at an early stage. Soil Category 1 = gravel, coarse sand; rapid draining; Soil Category 2 = coarse to medium sand; free draining; Soil Category 3 = medium-fine and loamy sand; good drainage; Soil Category 4 = sandy loam, loam and silt loam; moderate drainage; Soil Category 5 = sandy clay-loam, clay-loam and silty clay-loam; moderate to slow drainage. 2 The values in the average daily flow column are to be used in the design sizing of trench systems for domestic wastewater producing facilities serving staff/employees in office, commercial, retail and light industrial premises. Where flows are below 1,000 litres/day, then trench lengths may be pro rata reduced down to, but to not less than 50% of those for 1,000 litres/day. 93

6 Schedule 1 On-Site Effluent Treatment Environment Bay of Plenty Table 7 is based on the following: 0.45 metre wide gravel filled standard trench (Figure 4 trench configuration). The width of the trench may be reduced as long as the trench length from Table 7 is increased by the following formula: Narrow Trench Length = (T x 0.45) W where T = trench length from Table 7 W = trench width. The trench width must not exceed 0.45 metres. D = spacing between adjacent trenches (sidewall to sidewall). The minimum is 1 metre although 2 metres is preferable (see diagram below). Ground surface 1 metre 100% reserve area so that if the soakage field fails, there is room to develop another field. For discretionary activities these lengths may exceed those recommended in Table 7. Any compaction of a soakage field is to be avoided. 94

7 Environment Bay of Plenty On-Site Effluent Treatment Schedule 1 Figure 5 Low-Pressure-Effluent-Distribution (LPED) for Standard Trenches 95

8 Schedule 1 On-Site Effluent Treatment Environment Bay of Plenty Table 8 Modification Factors for Conventional On-Site Effluent Treatment Systems The following improvements may be used to modify the treatment or site conditions if the total score from Table 6 exceeds 4. Limiting Factors Requirement Solution or Recommendation for 1 Pre-treatment Level 2 Groundwater Too High 3 Restrictive Soil Horizon 4 Horizontal Barrier 5 Proximity to Surface Water Improve the pre-treatment level Raise soakage field to allow 600 millimetres clearance for conventional systems or improve the pretreatment level - remove restriction - increase depth to restriction - decrease loading - improve pre-treatment Type of Specific Advice Select improved system from Table 6 - Raise soakage field to level with ground - mound systems - advanced treatment system and irrigation lines. - break up iron pan/clay pan - move soakage field across or up (e.g. mound) - advanced treatment system and irrigation lines. Increase distance to barrier Move system Increase distance to surface water - Improve pre-treatment level Move system - advanced treatment system and irrigation lines. Go Back to Table 6 Go to Rule 12 or 13 Go to Rule 12 or 13 Go to Rule 12 or 13 96

9 Environment Bay of Plenty On-Site Effluent Treatment Schedule 1 SOURCE Table 9 Wastewater Flow Design Allowances Households with standard facilities (including automatic washing machine) Typical Wastewater Flow Allowance in Litres/Person/Day [Note 1] On-site Roof Water Reticulated Tank Supply Community or Household Borewater Supply Households with standard water reduction fixtures [Note 2] Households with full water reduction facilities [Note 3] Households with full water reduction facilities plus reclaimed water recycle for water closet flushing [Note 4] Households with extra wastewater producing facilities (e.g. garbage grinders; douches) Households - blackwater only (standard facilities) Households - greywater only (standard facilities) Motels/Hotels - guests, resident staff - non-resident staff - reception rooms - bar trade (per customer) - restaurant (per diner) Community Halls - banqueting - meetings Marae [Note 5] - day only visitors - day plus overnight visitors Restaurants (per diner) - dinner - lunch Tea Rooms (per customer) - without restroom facilities - with restroom facilities Schools (pupils plus staff) [Note 6] Rural Factories, Shopping Centres (staff) Public toilets (including hand wash) [Note 7] 8 10 Camping Grounds - fully serviced - recreation areas Advisory Notes: 1 These flows are recommended minimums for design purposes (unless actual flows from past experience are available). 2 Standard water reduction fixtures include dual flush 11/5.5 litre water closets, shower flow restrictors, aerator faucets (taps), water conserving automatic washing machines. 3 Full water reduction fixtures include the combined use of reduced flush 6/3 litre water closets, shower flow restrictors, aerator faucets, front-load washing machines and flow/pressure control inserts on all water use outlets. 4 As for Note 3, plus on-site greywater treatment and recycle to toilet cistern, or on-site/off-site treatment and recycle of reclaimed water for water closet flushing. 5 Assumes that lunches and lunch/dinners will be served, and that overnight visitors have access to showers. 6 Based upon experience in the Auckland area, these values for schools are conservative. Recorded flows appear to be around 15 litres/person/day on rainwater tank supply, and 20 litres/person/day on community or borewater supply. 7 These are aggregate values applied to total daily visitor numbers (male and female) Reference Sources: Gunn I (1994) On Site Wastewater Disposal from Households and Institutions. ARC Environmental Technical Publication No. 58 (Second Edition); AS/NZS 1547:2000; On-Site NewZ 99/1 (January 1999). 97

10 Schedule 1 On-Site Effluent Treatment Environment Bay of Plenty Table 10 Appearance and Feeling of Various Soil Textural Classes Soil Appearance and Feeling Textural Class Dry Soil Moist Soil Sand Loamy Sand Sandy Loam Loam Silt Loam Silty Clay Loam Silty Clay Loose, single grains which feel gritty. Squeezed in the hand, the soil mass falls apart when the pressure is released. Loose, single grains, which feel gritty but enough fine particles to stain fingerprints in the palm of hand. Aggregates are easily crushed. Very faint, velvety feeling initially, but as rubbing is continued; the gritty feeling of sand soon dominates. Aggregates are crushed under moderate pressure; clods can be quite firm. When pulverised, loam has a velvety feel that becomes gritty with continued rubbing. Aggregates are firm but may be crushed under moderate pressure. Clods are firm to hard. Smooth, flour-like feel dominates when soil is pulverised. Aggregates are very firm. Clods are hard to very hard. Squeezed in the hand it forms a cast which crumbles when lightly touched. Does not form a ribbon between thumb and forefinger. Squeezed in the hand. It forms a cast that crumble when touched and only bears very careful handling. Forms a cast that bears careful handling without breaking. Doesn t form a ribbon between thumb and forefinger. Cast can be handled quite freely without breaking. Slight tendency to ribbon between thumb and forefinger. Rubbed surface is rough, Cast can be freely handled without breaking. Slight tendency to ribbon between thumb and forefinger. Rubbed surface has a broken or rippled appearance. Cast can be handled very firmly without breaking. Tendency to ribbon between thumb and forefinger with some flaking, greasy feeling, moderately sticky. Squeezed with proper moisture content into a long ribbon; sticky feel. 98

11 Environment Bay of Plenty On-Site Effluent Treatment Schedule 2 Schedule 2 System Design Requirements for New Advanced On-Site Effluent Treatment Systems to Meet Minimum Requirements for Permitted Activities This schedule specifies various design options for advanced on-site effluent treatment systems which meet the minimum requirements for permitted activities. In accordance with Rules 12 and 13 of the plan, new systems to be installed after the Operative On- Site Effluent Treatment became operative are permitted activities only if, among other requirements stated in the rule, the system meets certain minimum design standards specified in the following table. Advisory Notes: 1 Advanced on-site effluent treatment systems with a total score between 1 and 4 (inclusive) from Table 11 are permitted activities. 2 Advanced on-site effluent treatment systems with a total score of 5 or more from Table 11 are discretionary activities. Table 11 Factors Restricting Choice of Advanced On-Site Effluent Treatment System 1 Pre-Treatment Level (Maintenance access should be provided) Factor 1 st Score 2 nd Score (if necessary) Advanced treatment unit 1 2 Depth to Highest Groundwater Table Below bottom of soakage field land treatment area 6 greater than 1200 millimetres between millimetres between millimetres between millimetres 3 Soil Category (Refer to Table 10) 1 gravel, coarse sand; rapid draining; 2 coarse to medium sand; free draining; 3 medium-fine and loamy sand; good drainage; 4 sandy loam, loam and silt loam; moderate drainage; 5 sandy clay-loam, clay-loam and silty clayloam; moderate to slow drainage. 6 sandy clay, non-swelling clay and silty clay; slow drainage. 7 swelling clay, grey clay, hardpan; poorly or non-draining See Definition of Terms for definition of Treatment Area 99

12 Schedule 2 On-Site Effluent Treatment Environment Bay of Plenty 4 Restrictive Soil Horizon 7 (barrier to soil soakage) For irrigation line, i.e. pressure compensating emitters: Restrictive drainage soil horizon within 0.5 metres of soil surface. Restrictive drainage soil horizon deeper than 0.5 metres of soil surface. 5 Slope less than 15 percent slope (8.5 o ) greater than 15% (8.5 o ) 6 Barrier to Horizontal Soil Soakage Within 3 metres (For example vertical cuttings, retaining walls, building walls etc. in the soil profile) greater than 3 metres and greater than 45 degrees from the toe of a wall/embankment less than 3 metres or less than 45 degrees from the toe of the wall/embankment Proximity to Surface Water (including ephemeral) or Water Supply Bore (i) Greater than or equal to 30 metres (ii) Between metres (iii) Between metres (iv) Less than 20 metres TOTAL SCORE 7 A restrictive soil horizon maybe a change in soil textural class or some other change which severely reduces drainage. 100

13 Environment Bay of Plenty On-Site Effluent Treatment Schedule 2 Table 12 Modification Factors for Advanced On-Site Effluent Treatment Systems The following improvements may be used to modify the treatment or site conditions if the total score from Table 11 exceeds 5. Limiting Factors Requirement Solution or Recommendation for Type of Specific Advice 1 Pre-treatment Level Improve the pre- - Add disinfection treatment level 2 Groundwater too High Improve the clearance to groundwater 3 Restrictive Soil Horizon - Remove the restriction - Increase depth to restriction - Decrease loading - Improve the pretreatment level 4 Horizontal barrier - Increase distance to barrier - Add nutrient removal - Provide raised bed for effluent land application - Improve pretreatment level by adding disinfection - Break up iron pan/clay pan- Provide raised bed for effluent land application - Change DIR 1 from 5mm/d to 3mm/d - Change DIR from 5mm/d to 2mm/d - Add disinfection - Add disinfection and nutrient removal - Relocate land application area Go Back to Table 11 or apply for discharge permit Apply for discharge permit Go Back to Table 11. Apply for discharge permit. Go Back to Table 11. Go Back to Table 11. Apply for discharge permit. Apply for discharge permit. Apply for discharge permit. Apply for discharge permit. Go back to Table 11 5 Proximity to Surface Water - Improve the pretreatment level - Increase distance to surface water - Improve the pretreatment level - Add disinfection - Add disinfection and nutrient removal - Relocate land application area - Add disinfection - Add disinfection and nutrient removal Apply for discharge permit. Apply for discharge permit. Go back to Table 11. Apply for discharge permit. Apply for discharge permit. 101

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15 Environment Bay of Plenty On-Site Effluent Treatment Schedule 3 Schedule 3 Performance Conditions for Existing Systems Installed before the On-Site Effluent Treatment Regional Plan became operative (1 December 1996) General Authorisation No 9 The discharge of up to 2 m 3 /day of natural water containing waste from septic tanks or any other domestic sewage system into the ground provided that: (a) The section area is not less than 1,500 m 2 (if subdivided 6 after 1 February 1991). (b) Septic tank density does not exceed 1/1,500 m 2 within the property boundary where additional dwellings and accompanying septic tank systems are installed after 1 February (c) For that area of Waihi Beach previously covered by the Hauraki Catchment Board General Authorisation Number 14, the section area is to be not less than 1,500 m 2 and septic tank density is not to exceed 1/1,500 m 2 irrespective of date of subdivision. (d) The discharge of effluent is not likely to adversely affect land stability, any adjoining landowner or to become detectable in the surrounding water resources (refer notes 1 and 3). (e) A waste disposal unit (garbage grinder) is not installed unless the effluent system design makes specific allowance for this use (applies to systems installed after 1 February 1991 or existing septic tanks without a grinder) (refer note 3). (f) Any septic tank installed after 1 February 1991 has a minimum of 600mm depth to water table below the soakage bed at all times or 2,000 mm if a soak hole is used (refer notes 2 and 3). (g) The septic tank treatment and disposal system complies with the city/district council requirements. The design and installation is in accordance with NZS Standard Number 4610:1982 (refer note 3). (h) The septic tank treatment and disposal system is operated and maintained in accordance with NZSI Standard Number 4610:1982 (refer note 3). (i) The discharge shall not cause or constitute a nuisance as defined in the Health Act (refer note 3). (j) There is no reticulated sewerage system available (refer note 3). NOTES: 1 Care should be taken to ensure that the treatment system will not cause contamination of any water supply. 2 In order to meet Condition f of the General Authorisation a raised bed or built up disposal area may be used. Such a system should conform to the principles outline in the Council's guideline for such systems. 3 Conditions d, e, f, g, h, i and j apply to all installations undertaken, irrespective of either section size or when the section was subdivided. 6 Definition of subdivided: subdivision, cross lease or partition 103

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17 Environment Bay of Plenty On-Site Effluent Treatment Schedule 4 Schedule 4 Performance Conditions for Existing Systems Installed after the On-Site Effluent Treatment Regional Plan became operative (1 December 1996) but before the On-Site Effluent Treatment became Operative (A) 6.2.4(a) 6.2.4(a)(i) Conventional On-Site Effluent Treatment Systems Rules The discharge of up to 2 cubic metres per day of treated wastewater into land from a conventional on-site effluent treatment system is a permitted activity provided that: Conditions (a) (b) Subject to Rule 6.7.4(a)(i) in Schedule 4, for systems existing prior to the plan becoming operative, those systems shall comply with the requirements of Schedule 3, or; Subject to Rule 6.2.4(a)(i) in Schedule 4, for systems to be installed after the plan became operative (1 December 1996), those systems shall comply with the following: (i) (ii) The site for the system is not subject to slippage, subsidence, erosion or inundation from any source. The land application area is located not less than 15 metres from any drinking water bore and 5 metres from any surface water 8. (iii) The requirements set out in Tables 6.1, 6.2 and 6.3 in Schedule 4 (iv) (v) (vi) Each system is unable to connect to an existing reticulation system (for the purposes of this condition, where not otherwise specified in a District Plan, a system is deemed to be unable to connect if the reticulation system is more than 30 metres from the owner s land or more than 60 metres from the nearest part of the building containing wastewater producing fixtures). There is no overland flow or surface ponding as a result of the discharge of the wastewater. In addition any on-site effluent treatment system located in the communities specified in 6.7.4(a)(i) in Schedule 4 must also comply with the following: 8 Environment Bay of Plenty will work with Territorial authorities, Regional Authorities and other interested parties to formulate and agree on a consistent set of buffers. 105

18 Schedule 4 On-Site Effluent Treatment Environment Bay of Plenty Each system is subject to a septic tank survey and a regular maintenance programme under which the owner of the system is required to obtain at intervals not greater than three (3) years, a certificate issued by Environment Bay of Plenty following an inspection carried out by a certifier approved by Environment Bay of Plenty certifying that the system meets the conditions set out under Rules 6.2.4(a)(i)(b), 6.3.4(a)(i) and 6.8.4(b)(i) in Schedule 4. Or each system is subject to a septic tank survey and a regular maintenance programme under which the owner of the system is required to obtain a certificate of compliance at intervals not greater than six (6) years if the: (vii) Septic tank of the dwelling with no more than three (3) bedrooms has a liquid volume of greater than 2,700 litres, or has a liquid volume greater than 2,000 litres and is fitted with an effluent filter on the outlet of the tank; or (viii) Septic tank of the dwelling with no more than six (6) bedrooms has a liquid volume of greater than 3,300 litres, or has a liquid volume greater than 2,500 litres and is fitted with an effluent filter on the outlet of the tank; The certificate shall be issued by Environment Bay of Plenty following an inspection carried out by a certifier approved by Environment Bay of Plenty, certifying that the system meets the conditions set out under Rules 6.2.4(a)(i)(b), 6.3.4(a)(i) and 6.8.4(b)(i) in Schedule 4. Or each system is subject to a septic tank survey and a regular maintenance programme every 3 years administered by the city/district council for the area. (c) Notwithstanding 6.2.4(a)(i)(b)(ii) in Schedule 4, for systems installed after Plan Change No. 1 becomes operative (6 December 2002), the land application area shall be located not less than 20 metres from any drinking water bore and 20 metres from any surface water (a)(ii) Nothing in Rule 6.2.4(a)(i) in Schedule 4 shall require conventional on-site effluent treatment systems installed between 1 December 1996 and 19 December 2000 to achieve performance standards in Tables 6.1, 6.2 and 6.3 of Schedule 4 that are more restrictive than that required prior to notification of Change No. 1 to this plan unless: (a) (b) The system did not comply with this plan at the time the plan change was publicly notified (19 December 2000); or The system requires upgrading as provided for in Rule 6.8.4(b)(i) in Schedule (a)(iii) 6.2.4(a) (iv) Where conventional effluent treatment system fails to comply with Rule 6.2.4(a)(i) in Schedule 4 the discharge shall be a discretionary activity 9. The discharge to soak holes constructed after the date this plan becomes operative is a discretionary activity, requiring an assessment of environmental effects. 9 Details of the criteria Environment Bay of Plenty will use to assess applications for discretionary activity can be found in Appendix F. Where a suitable Treatment Area cannot be found on the Lot (section) a discharge permit may be applied for from Environment Bay of Plenty 106

19 Environment Bay of Plenty On-Site Effluent Treatment Schedule (a)(v) 6.2.4(a)(vi) The use of explosives to maintain soakhole infiltration is a prohibited activity. Discharges from conventional on-site effluent treatment systems shall comply with Rule 6.2.4(a)(i) in Schedule 4 except for urban zoned (residential, commercial, recreational or industrial) areas within the Tauranga City Council boundary in which case the discharges shall be a discretionary activity for systems installed after this plan becomes operative Methods of Implementation 6.2.4(a) 6.2.4(a)(i) Rules The discharge of up to 2 cubic metres per day of treated wastewater into land from a conventional on-site effluent treatment system is a permitted activity provided that: Conditions (a) (b) Subject to Rule 6.7.4(a)(i), for systems existing prior to the plan becoming operative, those systems shall comply with the requirements of Appendix B, or; Subject to Rule 6.2.4(a)(i), for systems to be installed after the plan became operative (1 December 1996), those systems shall comply with the following: (i) (ii) The site for the system is not subject to slippage, subsidence, erosion or inundation from any source. The land application area is located not less than 15 metres from any drinking water bore and 5 metres from any surface water 9. (iii) The requirements set out in Tables 6.1, 6.2 and 6.3 in Section (iv) (v) (vi) Each system is unable to connect to an existing reticulation system (for the purposes of this condition, where not otherwise specified in a District Plan, a system is deemed to be unable to connect if the reticulation system is more than 30 metres from the owner s land or more than 60 metres from the nearest part of the building containing wastewater producing fixtures). There is no overland flow or surface ponding as a result of the discharge of the wastewater. In addition any on-site effluent treatment system located in the communities specified in 6.7.4(a)(i) must also comply with the following: Each system is subject to a septic tank survey and a regular maintenance programme under which the owner of the system is required to obtain at intervals not greater than three (3) years, a certificate issued by Environment Bay of Plenty following an inspection carried out by a certifier approved by Environment Bay of Plenty certifying that the system meets the conditions set out under Rules 6.2.4(a)(i)(b), 6.3.4(a)(i) and 6.8.4(b)(i). 9 Environment Bay of Plenty will work with Territorial Authorities, Regional Authorities and other interested parties to formulate and agree on a consistent set of buffers. 107

20 Schedule 4 On-Site Effluent Treatment Environment Bay of Plenty Or each system is subject to a septic tank survey and a regular maintenance programme under which the owner of the system is required to obtain a certificate of compliance at intervals not greater than six (6) years if the: (vii) Septic tank of the dwelling with no more than three (3) bedrooms has a liquid volume of greater than 2,700 litres or has a liquid volume greater than 2,000 litres and is fitted with an effluent filter on the outlet of the tank; or (viii) Septic tank of the dwelling with no more than six (6) bedrooms has a liquid volume of greater than 3,300 litres or has a liquid volume greater than 2,500 litres and is fitted with an effluent filter on the outlet of the tank; The certificate shall be issued by Environment Bay of Plenty following an inspection carried out by a certifier approved by Environment Bay of Plenty, certifying that the system meets the conditions set out under Rules 6.2.4(a)(i)(b), 6.3.4(a)(i) and 6.8.4(b)(i). Or each system is subject to a septic tank survey and a regular maintenance programme every 3 years administered by the territorial authority for the area. (c) Notwithstanding 6.2.4(a)(i)(b)(ii), for systems installed after Plan Change No. 1 becomes operative (6 December 2002), the land application area shall be located not less than 20 metres from any drinking water bore and 20 metres from any surface water (a)(ii) Nothing in Rule 6.2.4(a)(i) shall require conventional on-site effluent treatment systems installed between 1 December 1996 and 19 December 2000 to achieve performance standards in Tables 6.1, 6.2 and 6.3 of Section 6.15 that are more restrictive than that required prior to notification of Change No. 1 to this plan unless: (a) (b) The system did not comply with this plan at the time the plan change was publicly notified (19 December 2000); or The system requires upgrading as provided for in Rule 6.8.4(b)(i). 108

21 Environment Bay of Plenty On-Site Effluent Treatment Schedule Methods of Implementation 6.3.4(a) 6.3.4(a)(i) Rules The discharge of treated wastewater into land from an advanced on-site effluent treatment system is a permitted activity provided that: Conditions (a) The maximum discharge does not exceed 2 cubic metres per day; (b) The site for the system is not subject to slippage, subsidence, erosion or inundation from any source; (c) (d) (e) (f) (g) (h) (i) (j) (k) (l) (m) The land application area is located not less than 20 metres from any drinking water bore and 20 metres from any surface water 9 ; Each system is unable to connect to an existing reticulation system (for the purposes of this condition, where otherwise not specified in a district plan, a system is deemed to be unable to connect if the reticulation system is more than 30 metres from the owner s land or more than 60 metres from the nearest part of the building containing wastewater producing fixtures). The system complies with the requirements set out in Table 6.2 in Section 6.15; The wastewater flow receives advanced treatment such that the effluent quality shall not be less than a secondary treatment standard of 30 grams per cubic metres of BOD 5 and 45 grams per cubic metres of suspended solids prior to discharge to the dispersal system; Secondary treated wastewater shall be applied by sub-surface irrigation at a rate not exceeding 5 litres per square metres per day; Irrigation lines emitters used for the dispersal of treated wastewater shall be installed either: (i) beneath the surface of the soil between 100 millimetres 200 millimetres; or (ii) on the surface of the soil and covered by an inert material (e.g. bark), or an appropriate alternative, to a minimum depth of 100 millimetres; Subject to condition (g) above, the horizontal separation distance between irrigation lines emitters shall be set to ensure that an even distribution of treated wastewater to the ground occurs; There is no overland flow or surface ponding as a result of the discharge of the wastewater; There is no land application by surface irrigation or any method which may produce any aerosol discharge into air; Subject to condition (f) above, the pre-treatment and dispersal system shall be operated and maintained in accordance with the manufacturer s design specification for effluent quality including regular desludging; A written record of all servicing and maintenance carried out on the wastewater treatment system shall be kept and a copy of this record shall be forwarded to Environment Bay of Plenty within 90 days of a service or maintenance check required by condition (l) above; 9 Environment Bay of Plenty will work with Territorial Authorities, Regional Authorities and other interested parties to formulate and agree on a consistent set of buffers. 109

22 Schedule 4 On-Site Effluent Treatment Environment Bay of Plenty (n) (o) A certificate of performance shall be lodged by the manufacturer with Environment Bay of Plenty. The certificate shall include the following information: (i) Test/trial results demonstrating that the type of pre-treatment unit, if correctly installed and maintained, will meet the conditions set out in this rule; (ii) The minimum maintenance requirements for the system; (iii) Whether the pre-treatment unit design makes specific allowance for a waste disposal unit (garbage grinder); and Certification is also required by Environment Bay of Plenty from the installer that the system has been installed to the manufacturer s specifications Methods of Implementation 6.7.4(a) 6.7.4(a)(i) Rule Discharges into land from conventional on-site effluent treatment systems located in urban zoned (residential, commercial, recreational, industrial, lake (lakeside settlement), rural residential or future urban) areas of the communities of Maketu, Little Waihi Reclamation Area, Waihi Beach, Omokoroa, Tarawera, Okareka, Tanners Point, Athenree, Woodlands, Gisborne Point, Hamurana, Hinehopu, Okawa Bay and Mourea and in existence prior to the plan becoming operative shall be a discretionary activity three years after the date this plan became operative (1 December 1996) unless within that time: (a) (b) Each system is subject to septic tank survey and a regular maintenance programme under which the owner of the system is required to obtain at intervals not greater than three (3) years, a certificate issued by Environment Bay of Plenty following an inspection carried out by a certifier approved by Environment Bay of Plenty certifying that the system meets the conditions set out under Rules 6.2.4(a)(i)(b), 6.3.4(a)(i) and 6.8.4(b)(i). Or each system is subject to a septic tank survey and a regular maintenance programme under which the owner of the system is required to obtain a certificate of compliance at intervals not greater than (6) six years if the: (i) (ii) septic tank of the dwelling with no more than three (3) bedrooms has a liquid volume of greater than 2,700 litres or has a liquid volume greater than 2,000 litres and is fitted with an effluent filter on the outlet of the tank; or septic tank of the dwelling with no more than six (6) bedrooms has a liquid volume of greater than 3,300 litres or has a liquid volume greater than 2,500 litres and is fitted with an effluent filter on the outlet of the tank; (c) The certificate shall be issued by Environment Bay of Plenty following an inspection carried out by a certifier approved by Environment Bay of Plenty certifying that the system meets the conditions set out under Rules 6.2.4(a)(i)(b), 6.3.4(a)(i) and 6.8.4(b)(i). 110

23 Environment Bay of Plenty On-Site Effluent Treatment Schedule 4 Or each system is subject to a septic tank survey and regular maintenance programme every 3 years administered by the territorial authority for the area. In which case they shall be permitted activities. (d) A Septic Tank Survey is defined as a survey where all properties containing septic tanks are visited, the tank contents are pumped out, the capacity and structural integrity of the tank is assessed and an assessment is made of the capacity and operational performance of the soakage field or soakhole. Note: Please note that for any advanced on-site effluent treatment systems outlined in section 6.3, Rule 6.3.4(a)(i)(m) requires that a written record of all servicing and maintenance carried out on the wastewater treatment system shall be kept and a copy of this record shall be forwarded to Environment Bay of Plenty within 90 days of a service or maintenance check required by condition 6.3.4(a)(i)(l) (b) Rule 6.8.4(b)(i) Where an on-site effluent treatment system fails, the system shall be upgraded, or replaced with a new system that complies with either Rule 6.2.4(a)(i)(b) or Rule 6.3.4(a)(i). Table 6.1: Septic Tank Capacities A: Number of Bedrooms Minimum Tank Capacity/Size (Litres)* 1 to 3 2,700 4 to 6 3,300 7 or more Probably exceeds 2 cubic metres per day and therefore is discretionary. Note: *As volume measured from outlet invert to septic tank base (i.e. liquid volume). If a garbage grinder is installed in a conventional effluent system, then: Effluent outlet filter should be installed at the outlet of the septic tank to protect the soakage field, or the tank size is increased to the larger size to accommodate the extra solids produced. B: Households (Blocks of Units/Flats) (Refer to Table 6.5) For 10 persons or more the capacity (C) may be determined by the formula C = (P x A) + 2,000 litres where P = the number of persons to be served and A = the daily wastewater flow allowance in litres/person/day 111

24 Schedule 4 On-Site Effluent Treatment Environment Bay of Plenty C: Institutions (Refer to Table 6.5) For flows greater than 700 litres per day the capacity (C) may be determined by the formulae as set out below: Motels/Hotels - without restaurant C = (P x A) + 2,000 litres - with restaurant C = (P x A) + 3,000 litres Community halls, schools, rural factories, shopping centres, camping grounds C = (P x A) + 2,000 litres where P = the number of persons to be served and A = the daily wastewater flow allowance in litres per person per day 112

25 Environment Bay of Plenty On-Site Effluent Treatment Schedule 4 Table 6.2: Factors restricting choice of system Select one item from each of numbered sections below and put the score in 1st score column to find out first score. On-site effluent treatment systems with a total score between 1 and 3 (inclusive) from Table 6.2 are permitted activities provided they meet the requirements of Rules 6.2.4(a)(i) and (a)(i). On-site effluent treatment systems with a score of 4 or more from Table 6.2 are discretionary activities unless the systems can be modified in accordance with the modification factors set out in Table Pre-Treatment Level (Maintenance access should be provided) (a) Single stage septic tank (b) Two stage septic tank or single stage septic tank and approved effluent outlet filter (c) Two stage septic tank and approved effluent outlet filter (d) Greywater only (e) Advanced treatment unit Factor st Score 2 nd Score (if necessary) 2 Depth to Highest Groundwater Table (a) (b) Conventional On-Site Effluent Systems below bottom of soakage field land treatment area (refer to definition of treatment area in Appendix M) greater than 600 millimetres less than 600 millimetres Advanced On-Site Effluent Systems Below bottom of the irrigation lines e.g. pressure compensating emitters for treatment level 1(e) above greater than 300 millimetres less than 300 millimetres Soil Category (Refer to Table 6) 1 gravel, coarse sand; rapid draining; 2 coarse to medium sand; free draining; 3 medium-fine and loamy sand; good drainage; 4 sandy loam, loam and silt loam; moderate drainage; 5 sandy clay-loam, clay-loam and silty clayloam; moderate to slow drainage *A restrictive soil horizon maybe a change in soil textural class or some other change which severely reduces drainage. 113

26 Schedule 4 On-Site Effluent Treatment Environment Bay of Plenty 4 Restrictive Soil Horizon* (barrier to soil soakage) Restrictive drainage soil horizon* within 2 metres of soil surface. Restrictive drainage soil horizon deeper than 2 metres of soil surface. 3 0 For irrigation lines e.g. pressure compensating emitters: 5 Slope Restrictive drainage soil horizon within 0.5 metres of soil surface. Restrictive drainage soil horizon deeper than 0.5 metres of soil surface. less than15 percent slope (8.5 o ) greater than 15% (8.5 o ) 6 Barrier to Horizontal Soil Soakage Within 5 metres (For example vertical cuttings, retaining walls, building walls etc. in the soil profile) No Yes For irrigation lines e.g. pressure compensating emitters. No Yes Proximity to Surface Water (including ephemeral) or Water Supply Bore (a) For systems installed after 1 December 1996 to the date Plan Change No 1 becomes operative: (i) (ii) (iii) Greater than or equal to 20 metres Greater than or equal to 5 metres, but less than 20 metres less than 5 metres (b) For systems installed after Plan Change No 1 becomes operative (6 December 2002): (i) Greater or equal to 20 metres (ii) Less than 20 metres TOTAL SCORE

27 Environment Bay of Plenty On-Site Effluent Treatment Schedule 4 Table 6.3: Effluent treatment trench length required (in metres) for discharge volumes of up to 2 cubic metres per day to standard trenches Soil Category 1 (**LPED) Average daily flow (L) Number of Bedrooms Min. Trench Length (metres) Req. Area Req. (metres 2 ) incl. Reserve Area Min. Trench Length (metres) Req. Area Req. (metres 2 ) incl. Reserve Area Min. Trench Length (metres) Req. Area Req. (metres 2 ) incl. Reserve Area Min. Trench Length (metres) Req. Area Req. (metres 2 ) incl. Reserve Area Min. Trench Length (metres) Req. Area Req. (metres 2 ) incl. Reserve Area Up to 500* Up to to More than or more Expected to exceed 2 cubic metres per day * This applies to non-habitable dwellings that is not inhabited by humans and includes a building that is not used for temporary accommodation such as offices or service stations for example. ** For all category 1 soils a low pressure effluent distribution system (LPED) must be used. This system utilises pump dosed loading from a perforated small diameter pipe inserted within trenches (refer to Figure 6.2). Designed for use in free draining standard distribution lines in standard trenches (refer to Figure 6.1) or in shallow and narrow soils (category 1 - gravel, coarse sand; rapid draining) it is essentially a variation on conventional distributions systems. Soil Category 1 Soil Category 2 Soil Category 3 Soil Category 4 Soil Category 5 = gravel, coarse sand; rapid draining; = coarse to medium sand; free draining; = medium-fine and loamy sand; good drainage; = sandy loam, loam and silt loam; moderate drainage; = sandy clay-loam, clay-loam and silty clay-loam; moderate to slow drainage. If an LPED or pump system is used, an alarm/warning system is required to detect failure of the system at an early stage. Table 6.3 is based on the following: 0.45 metre wide gravel filled standard trench (Figure 6.1 trench configuration). The width of the trench may be reduced (Figure 6.2 trench configuration) as long as the trench length from Table 6.3 is increased by the following formula: Narrow Trench Length = (T x 0.45) W where T = trench length from Table 6.3 W = trench width. The trench width must not exceed 0.45 metres. D = spacing between adjacent trenches (sidewall to sidewall). The minimum is 1 metre although 2 metres is preferable (see diagram below). 115

28 Schedule 4 On-Site Effluent Treatment Environment Bay of Plenty Ground surface 1 metre 100% reserve area so that if the soakage field fails, there is room to develop another field. For discretionary activities these lengths may exceed those recommended in Table 6.3. Any compaction of a soakage field is to be avoided. 116

29 Environment Bay of Plenty On-Site Effluent Treatment Schedule 4 117

30 Schedule 4 On-Site Effluent Treatment Environment Bay of Plenty 118

31 Environment Bay of Plenty On-Site Effluent Treatment Schedule 4 B Performance Conditions (see Rule 6.2.4(a)(i)) General Authorisation No 9 The discharge of up to 2 m 3 /day of natural water containing waste from septic tanks or any other domestic sewage system into the ground provided that: (a) The section area is not less than 1,500 m 2 (if subdivided 8 after 1 February 1991). (b) Septic tank density does not exceed 1/1,500 m 2 within the property boundary where additional dwellings and accompanying septic tank systems are installed after 1 February (c) For that area of Waihi Beach previously covered by the Hauraki Catchment Board General Authorisation Number 14, the section area is to be not less than 1,500 m 2 and septic tank density is not to exceed 1/1,500 m 2 irrespective of date of subdivision. (d) The discharge of effluent is not likely to adversely affect land stability, any adjoining landowner or to become detectable in the surrounding water resources (refer notes 1 and 3). (e) A waste disposal unit (garbage grinder) is not installed unless the effluent system design makes specific allowance for this use (applies to systems installed after 1 February 1991 or existing septic tanks without a grinder) (refer note 3). (f) Any septic tank installed after 1 February 1991 has a minimum of 600 mm depth to water table below the soakage bed at all times or 2,000 mm if a soak hole is used (refer notes 2 and 3). (g) The septic tank treatment and disposal system complies with the Territorial Local Authority requirements. The design and installation is in accordance with NZS Standard Number 4610:1982 (refer note 3). (h) The septic tank treatment and disposal system is operated and maintained in accordance with NZSI Standard Number 4610:1982 (refer note 3). (i) The discharge shall not cause or constitute a nuisance as defined in the Health Act (refer note 3). (j) There is no reticulated sewerage system available (refer note 3). NOTES: 1 Care should be taken to ensure that the treatment system will not cause contamination of any water supply. 2 In order to meet Condition f of the General Authorisation a raised bed or built up disposal area may be used. Such a system should conform to the principles outline in the Council's guideline for such systems. 3 Conditions d, e, f, g, h, i and j apply to all installations undertaken, irrespective of either section size or when the section was subdivided. 108 Definition of subdivided: subdivision, cross lease or partition. 119

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33 Environment Bay of Plenty On-Site Effluent Treatment Schedule 5 Schedule 5 Maps of Rotorua Lakes Catchments Map 4 Map 5 Map 6 Map 7 Map 8 Map 9 Map 10 Rotorua Lakes Catchments Lakes Rotoehu and Rotoma Lakes Rotoiti and Rotokawau Lakes Okataina & Okareka Lakes Tarawera, Tikitapu and Rotokakahi Lakes Rotomahana, Rerewhakaaitu and Okaro Lake Rotorua 121

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35 Environment Bay of Plenty On-Site Effluent Treatment Schedule 5 Map 4 Rotorua Lakes Catchment 123

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37 Environment Bay of Plenty On-Site Effluent Treatment Schedule 5 Map 5 Lakes Rotoehu and Rotoma 125

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39 Environment Bay of Plenty On-Site Effluent Treatment Schedule 5 Map 6 Lakes Rotoiti and Rotokawau 127

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41 Environment Bay of Plenty On-Site Effluent Treatment Schedule 5 Map 7 Lakes Okataina and Okareka 129

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43 Environment Bay of Plenty On-Site Effluent Treatment Schedule 5 Map 8 Lakes Tarawera, Tikitapu and Rotokakahi 131