Rotorua Lakes Catchment
Since 2005 many advanced (aerobic) wastewater treatment systems (also known as On-site effluent treatment or OSET) have gone through the trial facility established by Bay of Plenty Regional Council (in conjunction with Environment Waikato and Rotorua District Council) and now operated by Rotorua District Council, to determine which system could meet the approved standard.
The table below highlights the systems approved for installation in the Rotorua lakes' catchments. All systems shown may be installed elsewhere in the Bay of Plenty, however conventional septic tanks are still permitted in most areas outside Rotorua lake catchments. Unless there is a council sewerage scheme planned for your area, any new septic systems installed into the Rotorua catchment must be of an approved model or a resource consent needs to be obtained.
| Trial 1 (2005-2006)* See Trial 1 Note below | Approved for installation in Rotorua Catchments | Irrigation Pump included in test? | Measured power use (kWh) per day? | Equivalent annual power cost |
| Devan Blue DB900NRS (564KB, pdf) | - | Yes | 6.3 | $517 |
| Hynds Lifestyle (564KB, pdf) | - | Yes | 1.7 | $140 |
| Innoflow AdvanTex Ax20 (564KB, pdf) | - | No | 0.6 | $49 |
| Oasis Membrane MBR (564KB, pdf) | - | Yes | 7.3 | $600 |
| Smith and Loveless (Microfast 0.5) (564KB, pdf) | - | No | 7.2 | $591 |
| Biolytix BF6 2500 PAT (564KB, pdf) | - | Yes?1 | 0.2 | $16 |
| Supertreat SB440 (N12) | - | Yes | 10.8 | $887 |
| Waipapa Tanks Nitro-Treat P-N-12-2 (refer to Note A) | - | - | - | - |
| Trial 2 (2006-2007) | Approved for installation in Rotorua Catchments | Irrigation Pump included in test? | Measured power use (kWh) per day? | Equivalent annual power cost |
| Bio-Microbics MicroFAST 0.9 (1.9MB, pdf) | - | Yes | 8.9 | $731 |
| Devan Blue 9000NRS (1.3MB, pdf) | - | Yes | 2.7 | $222 |
| Hynds Lifestyle Ultimate (1.6MB, pdf) | Yes | Yes1 | 2.2 | $181 |
| Reflection Textile EW (3MB, pdf) | - | Yes1 | 2.5 | $205 |
| RX Plastics Airtech 9000 NR (1.7MB, pdf) | Yes | Yes | 5.3 | $435 |
| RX Plastics Airtech 9000 (1.7MB, pdf) | - | Yes | 4.9 | $402 |
| Waipapa Tanks Econo Treat P-10-2 (3.1MB, pdf) | - | Yes | 1.3 | $107 |
| Trial 3 (2007 - 2008) | Approved for installation in Rotorua Catchments | Irrigation Pump included in test? | Measured power use (kWh) per day? | Equivalent annual power cost |
| Biocycle 6300 (476KB, pdf) | - | Yes | 2.5 | $205 |
| Innoflow AdvanTex AX20 (405KB, pdf) | Yes (refer to Note B) | Yes | 1.1 | $90 |
| Oasis Clearwater S2000 (541KB, pdf) | Yes | Yes | 2.0 | $162 |
| Waipapa Tanks Maxi-Treat MV-C3000 (610KB, pdf) | Yes | Yes | 8.4 |
$690 |
| Trial 4 (2007-2008) See Trial 4 note below | Approved for installation in Rotorua Catchments | Irrigation Pump included in test? | Measured power use (kWh) per day? | Equivalent annual power cost |
| WaterGurus NovaClear | - | Yes | 4.6 | $378 |
| Humes FR1 | Yes | Yes | 5.2 | $427 |
| Hynds Lifestyle | Yes | Yes | 1.8 | $148 |
| Waipapa Tanks Econo-Treat VBB C-2200-2 | Yes | Yes | 1.8 | $148 |
The On-Site Effluent Treatment (OSET) National Testing Programme (NTP) has now been taken over by Water NZ. Information about the trial and further results can be found here: http://www.waternz.org.nz/swans_oset.html
Trial 1 Note
In early 2009 Environment Bay of Plenty decided to no longer recognise the results of trial 1 for the purposes of approving waste water treatment systems for installation in our region. Trial 1 had a number of limitations in terms of flow variability which may have influenced systems' performance. The current trial facility has undergone a complete rebuild since the early days and now has very robust systems in place to ensure a high degree of flow uniformity and consistency.
Note 'A'
This system is almost identical to the trialled SuperTreat
SB440(N12) however is marketed by Waipapa Tanks and includes a
modified venturi (pat pend) for improved energy efficiency.
Note 'B'
This system may currently be installed as a permitted activity anywhere in the Bay of Plenty region, including the Rotorua lakes' catchments provided all other requirements of the On-Site Effluent Treatment Regional Plan are met. It is currently being re-tested in trial 5 to confirm its performance.
Notes on Power Use
- The irrigation pump trialled in the Reflection treatment system is too small for most irrigation applications. The electricity use in a Biolytix treatment system in a typical household setup totals about 0.6 kWh per day. Electricity use by irrigation pumps associated with household wastewater treatment systems is around 0.5 kWh per 1000 litres (i.e. approximate average household daily flow). This will vary depending on pump efficiency, difference in elevation, distance to irrigated area, pipe size etc.
- The electricity usage figures presented need to be treated with caution. Various factors could influence them including blockages and pump efficiency. Note that only some systems included irrigation pumps in the trial.
- The annual power cost was calculated using a nominal cost per kWh of 20 cents plus GST. The exact cost will vary depending on the region, pricing plan and discounts available.
Trial 4 Note
Trial 4 testing was the first full trial under OSET NTP supervision. SWANS-MAG Trial 4 audit reports are available on request through the individual companies. Company contact details are available from the Water NZ website here http://www.waternz.org.nz/documents/sigs/swans/100820_manufacturers_directory.pdf
The comparative results report for Trial 4 is not publically available as it is restricted to Funding Partners only. However, the performance are available to the public at the Water NZ website.
Other factors to consider
Visit our page about choosing a system.
Read the Rotorua Lakes Factsheet on the Onsite Treatment Regional Plan
If you want to install an advanced system, rule 13 of the On-site Effluent Treatment Regional Plan applies.
Existing conventional septic tank systems in Rotorua Lakes' Catchments
Unless connected to a sewer by December 2010 most conventional septic tanks systems in the catchments of Rotorua, Rotoiti, Rotoehu, Okaro and Okareka, will be required to upgrade to an approved advanced waste water treatment system. Those in Tarawera, Rotoma, and Hamurana have until December 2014.
Rotorua District Council plans to construct a sewerage system for the communities of Gisborne Point, Hamurana, Hinehopu, Rotoma, Okareka, and Tarawera. It is also examining the possibility of a sewerage scheme for a number of communities including Mamaku, Kennedy Bay, Tumoana Road, and Rerewhakaaitu.
Refer to rule 2 of the On-Site Effluent Treatment Regional Plan for more information.