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 Environment Bay of Plenty (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.

	Approved for installation in Rotorua Catchments	Irrigation Pump included in test?	Measured power use (kWh) per day?	Equivalent annual power cost
Trial 1 (2005-2006)* See Trial 1 Note below
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)
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)
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 (481KB, 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
WaterGurus NovaClear	-	Yes	4.6	$378
Humes FR1	Yes (Provisional)	Yes	5.2	$427
Hynds Lifestyle	Pending	Yes	1.8	$148
Waipapa Tanks Econo-Treat VBB C-2200-2	Yes (Provisional)	Yes	1.8	$148

The Rotorua trial site where these systems have been tested has made the transition to a national wastewater system test facility. An independent group called 'SWANS-MAG' ('Small Wastewater and Natural Systems – Management and Auditing Group') will grade results from trial 3 and all future trials.

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

1. 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.
2. 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.
3. 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

The results for this trial are provisional and subject to confirmation by SWANS-MAG early 2010.  In the interim, the two systems indicated as approved in trial 4 may be installed in all areas including Rotorua catchments as a permitted activity provided all other requirements of the On-Site Effluent Treatment Regional Plan are met.

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.