A guide to choosing a wastewater system - Biolytix

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A guide to choosing a wastewater system - Biolytix
A guide to
choosing a
wastewater
system
A guide to choosing a wastewater system - Biolytix
Choose the right system
                          for your property

                          One important decision you will need to make
                          when building or renovating outside of urban
                          areas is how to manage your wastewater. Most
                          rural properties in New Zealand do not have a
                          Council sewer to connect to and all household
                          wastewater needs to be treated and disposed
                          within the property boundaries. Septic tanks,
                          which do very little to treat the wastewater, are
                          becoming less acceptable to regulators and
                          society generally, and more advanced wastewater
                          treatment options need to be considered.

                          Choosing an advanced wastewater system can
                          be a complex process for most consumers. Claims
                          on company websites, brochures and quotes
                          from companies can be confusing, misleading
                          or unsubstantiated.

                          To make an informed choice for your wastewater
                          management, we recommend the following issues
                          are considered.

© Biolytix Limited 2017                                 01
A guide to choosing a wastewater system - Biolytix
1                      What level of                 1.   Primary treatment                may have more maintenance
                                                                                           requirements.

                       treatment do you
                                                     Primary Treatment (i.e. septic
                                                     tanks) provides minimal treatment     Higher levels of treatment will
                                                     of domestic wastewater which          generally be at higher capital and

                       need?                         is only suitable for ground
                                                     soakage by trenches. Primary
                                                                                           operating costs and maintenance
                                                                                           complexity – so it is important to
                                                     treated wastewater should not be      understand what level of treatment
                                                     disposed of using driplines.          is necessary for your property
                                                                                           and whether the manufacturer’s
                                                                                           claims about treated effluent
                                                     2.   Secondary treatment
                                                                                           levels can be substantiated. In
                                                                                           New Zealand there is the On-site
                                                     Secondary Treatment is a
                                                                                           Effluent Treatment National Testing
                                                     significant reduction in organic
                                                                                           Programme (OSET-NTP) which is
                                                     and particulate contaminants
                                                                                           the only independent trialling of
                                                     and is the most common level of
                                                                                           package wastewater treatment
                                                     treatment offered by package
                                                                                           plants in NZ. Further information
                                                     treatment plants in New Zealand.
                                                                                           about the OSET-NTP and test
                                                     Secondary treated effluent is
                                                                                           results for different package
                                                     usually suitable for land disposal
                                                                                           treatment plants can be found
                                                     via driplines.
                                                                                           at waternz.org.nz/OSET

                                                     3.   Tertiary treatment               It is important to note however the
                                                                                           OSET-NTP trials do not take into
                                                     Tertiary Treatment usually includes   account otherkey issues such
                                                     some level of disinfection or         as odour, noise, price, reliability,
                                                     nutrient removal. Tertiary treated    size, maintenance requirements,
                                                     effluent may be able to be            customer satisfaction etc.
                                                     disposed of closer to waterways
                                                     than primary or secondary
                                                     treatment. Some Councils have
                                                     regions (e.g. around Lake Taupo
                                                     and the Rotorua Lakes) where
                                                     wastewater systems are required
                                                     to remove a certain amount of
                                                     nutrient. Tertiary treatment will
                                                     usually be more expensive to
                                                     install and operate than primary
                                                     and secondary treatment, and
There are three main levels of treatment typically
offered for domestic wastewater.

                               02                                                          03
A guide to choosing a wastewater system - Biolytix
2                      What is the treatment                                    3                   Some Councils will only allow
                                                                                                    certain types of package

                       capacity?
                                                                                                    wastewater treatment plant, with
                                                                                                    the most common benchmark
                                                                                                    being whether the treatment plant
                                                                                                    has a performance certificate from
                                                                                                    the OSET-NTP trial (see above).
                                                                                                    Some Councils in New Zealand,
                                                                                                    such as the Bay of Plenty Regional
                                                                                                    Council, publish a list of treatment
                                                                                                    plants that meet their criteria for
                                                                                                    installation in their regions:

                                                                                                    boprc.govt.nz/environment/pollution-prevention-
                                                                                                    and-compliance/on-site-effluent-systems-oset/
                                                                                                    approved-on-site-effluent-systems/

How much wastewater can                It is important to ensure the capacity
be processed each day by               of your wastewater treatment plant
the treatment plant you are            comfortably exceeds the maximum
considering? Most package              volume of wastewater you are likely
treatment plants claim to be able to   to produce.
process a maximum volume of up
to between 1000 and 2000 litres per    The following are typical levels of
day. If you exceed the maximum         use in many New Zealand homes:

                                                                                Is the system
capacity of the treatment plant
it may overload the process,           •	1-3 bedroom house, 2 – 5
causing reduced treatment levels,         occupants: 300 to 1100 litres
odour or more maintenance costs.
Manufacturers will likely void the
                                          per day
                                       •	4-6 bedroom house, 6 – 10             approved for use
warranty if treatment capacity has
been exceeded.
                                          occupants: 1000 litres to 2200
                                          litres per day                        in your region?

                               04                                                              05
A guide to choosing a wastewater system - Biolytix
4   How much does it cost   Installed prices of secondary
                            package treatment plants typically
                                                                    •	Does the quote include electrical
                                                                       installation? If not then find out

    to purchase & install
                            range from $12,000 + GST to                what is involved and how much it
                            $25,000 + GST, with difficult or           is likely to cost.
                            remote sites being potentially more     •	Be wary of systems that claim to

    a package wastewater    expensive. We have noticed the
                            perception of the final price paid is
                                                                       not require a pump or electricity.
                                                                       In most circumstances dripline

    system in NZ?
                            often lost in the customer’s overall       disposal will require a pump to
                            building costs for the project. It is      deliver the minimum operational
                            best to obtain written quotes from         pressure.
                            suppliers and then check whether        •	Is the supply and installation
                            you are comparing ‘apples with             of the land disposal system
                            apples’ when comparing quotes.             included? Also check whether
                                                                       the quote includes burial or
                            We suggest at least confirming the         covering of the land disposal
                            following when comparing quotes:           system (which may be a
                                                                       Council requirement or an
                            • Does the quote include GST?              owner preference). This can
                            •	Does the quote include supply           be a significant additional
                               and installation?                       cost if excluded. We certainly
                            •	Does the quote include                  recommend dripline burial.
                               drainage? (This is typically         •	Are there exclusions like site
                               excluded from an initial quote          clearing, removal of spoil,
                               as it can be quite site-specific.       unforeseen excavation costs,
                               Look out for quotes that require        burial of disposal area etc?
                               separate greywater and
                               blackwater drainage, as this can
                               add significant additional cost).

      06                                                            07
5                        How much does                                       6                      Does it smell
                         it cost to operate                                                         or make lots of
                         a wastewater                                                               noise?
                         system?

                                                                             Wastewater treatment plants have
The initial capital cost is one issue   Keep in mind a house in Auckland     potential to create unpleasant
but the long term operating costs       connected to the Council sewer       odours and noise – especially if
are just as important. Try to get       and producing 1,000 litres per day   they are not operating properly.
some confirmation of what the           in wastewater will incur well over   Most brochures will claim ‘no
following annual costs will be:         $1000 per year in wastewater         odour’ but it is worth talking to
                                        charges.                             existing owners of treatment plants
•	Servicing costs (frequency and                                            you are considering to get some
   the cost per visit)                  It would not be unreasonable to      confirmation of whether the no
•	Electricity consumption (ask for     budget a similar amount per year     ‘odour claims’ are true.
   evidence, as some types              for an onsite wastewater plant
   of treatment technology use          (which should cover all operating    The same applies for noise. The
   20 to 30 times more electricity      costs, including an allowance        Australian New Zealand Standard
   than others)                         for occasional component             1546.3 recommends treatment
• Sludge removal                        replacements).                       plant noise should be less than
•	Component failure and                                                     40dB, but some treatment plants
   replacement.                                                              make a lot more noise. Ask the
                                                                             supplier to provide certification
                                                                             of compliance with this Standard
                                                                             recommendation.

                                  08                                                                               09
7   How reliable and   Product and installation quality
                       are critical issues to ensure
                                                             •	Have the manufacturer and
                                                                installer been in business for a

    reputable are
                       satisfactory long term operation of      sufficient length of time?
                       your wastewater system. Both the      •	Do the installer and manufacturer
                       installer and manufacturer should        have satisfied customer

    the manufacturer   be reputable, reliable and well
                       organised companies. We suggest
                                                                testimonials?
                                                             •	Are the installers ‘registered

    & installer?
                       you check the following:                 drainlayers’? Both the tank and
                                                                disposal field should be installed
                       •	Do the manufacturer and               by a Registered Drainlayer. You
                          installer carry adequate              can check current registration
                          insurances?                           status for New Zealand registered
                       •	Does the manufacturer or              here: https://www2.pgdb.co.nz/
                          installer have any Quality            PGDB/PublicRegister.aspx
                          Assurance accreditations?          •	How punctual was the installer
                       •	Does the manufacturer have            or manufacturer when making
                          any independent review of their       their site visit, sending a quote,
                          technology available?                 responding to emails/phone
                       •	Is the wastewater treatment           calls etc? This may give you
                          technology developed in New           some confidence in their ability
                          Zealand for New Zealand               to supply, install and service
                          conditions or was it imported         the system within the promised
                          from overseas?                        timeframes. You don’t want an
                       •	Is the manufacturer or installer      unnecessary delay to hold up
                          able to provide you with quality      other project works.
                          documentation such as Owner
                          Manuals, installer manuals,
                          specifications etc

      10                                                     11
8                       Wastewater                                               9                      Councils and other regulators
                                                                                                        often do not allow the use of

                        reports
                                                                                                        insinkerators in houses with onsite
                                                                                                        wastewater systems installed.
                                                                                                        However, many manufacturers
                                                                                                        claim their wastewater system is
                                                                                                        suitable for use with insinkerators.
                                                                                                        Use of an insinkerator at a house
                                                                                                        will significantly increase both
                                                                                                        the organic loading and the
                                                                                                        hydraulic loading, and we therefore
                                                                                                        recommend against one. Even if the
                                                                                                        wastewater system manufacturer
                                                                                                        claims their system is suitable for
Installation of a wastewater system     have an engineer in their company                               use with an insinkerator, there will
will require a Building Consent         able to provide a report as a                                   likely be increased energy use,
from your local council, and the        part of their total price, or at a                              maintenance cost and sludge
consent application will require an     reduced rate. Often companies                                   pump outs. Where possible, it
engineer’s wastewater report on         will request a deposit before this                              is better for a household with
site-specific issues such as:           report is provided. If you do get a                             an onsite wastewater system to
                                        manufacturer/installer to provide                               separately compost or bury their
•	the size and likely occupancy        a wastewater report you should                                  food scraps.
   of the house                         check their credentials:
•	the likely volume of wastewater
   generated each day                   •	Are they sufficiently qualified and
• the level of treatment required          experienced (e.g. an engineer,
•	the options for package                 geologist or similar)?
   wastewater treatment plants          •	Are they approved by Council
•	the type of soils present and           to author wastewater reports
   suitable loading rates for              in the region?
   those soils                          •	Are they sufficiently covered by
•	the size and location of the            a Professional Indemnity
   disposal area.                          insurance policy?

                                                                                 In-sink waste
                                        •	Will they visit your property to
In New Zealand, a wastewater               assess soils and site conditions,

                                                                                 disposal units
report is likely to cost between           and is this included in the cost?
$500 and $2,000 + GST if it is          •	Will they provide a ‘Producer
provided by an independent                 Statement’ after the installation
engineer, however some
manufacturers/installers may
                                           to allow you to get Council
                                           Completion Certification?             (insinkerators)

                                   12                                                              13
10                      What waste does an                                     11                      How often does a
                        onsite wastewater                                                              wastewater system
                        system treat?                                                                  need servicing?

Most package wastewater systems       The onus will be on you as the           Servicing frequencies and costs          •	Ask your manufacturer/installer/
are designed to treat all domestic    property owner to ensure only            can vary significantly between              service technician to confirm
household wastewater originating      biodegradable, non-toxic items           manufacturers, service technicians          service costs and frequencies
from toilets, showers, hand basins,   enter the wastewater treatment           and in different parts of the country.   •	Ask to see a Service Contract and
the laundry and the kitchen etc.      plant. Your manufacturer will            The Council will usually require            Service check sheet so you can
They are not normally designed        probably have a list of what can         a service contract to be in place           understand what service is being
to treat:                             and cannot be treated. Non-              between the property owner and              provided
                                      biodegradable or toxic items             a service technician. The service        •	Ask how long a service technician
•	Stormwater or surface water        entering the wastewater system           technician could be a part of               is typically onsite for a standard
   (e.g. rainwater tank overflows)    will likely result in additional often   the manufacturing company,                  service
•	Process waste (e.g. home           significant maintenance costs.           the installation company or a            •	Ask what the expected response
   hairdressing salons, home          If there is likely to be anything        third party provider. Servicing is          time is in the event of an alarm or
   brew waste)                        unusual about your wastewater,           something that is required at least         other malfunction?
•	Commercial laundry or              make sure you discuss this with the      annually and sometimes 3 to 4
   commercial food preparation        manufacturer.                            times per year, depending on the
•	Swimming pool or spa pool                                                   type of technology. Cost of a service
   backwash.                                                                   is usually in the range of $100 to
                                                                               $400 per service.

                                14                                                                                      15
12                     What size and                                            13                   The size of the disposal area is a
                                                                                                     function of the local Council rules,

                       weight are the
                                                                                                     the amount of treated wastewater
                                                                                                     being disposed of, the type of
                                                                                                     disposal and the type of soil at your

                       tanks?                                                                        property. The type of wastewater
                                                                                                     treatment plant you choose will
                                                                                                     generally not affect the size of
                                                                                                     the disposal area required. An
                                                                                                     average size house on poor soils
                                                                                                     will usually require around 300m2
                                                                                                     of disposal area if using pressure
                                                                                                     compensating dripline disposal.

Some wastewater systems require        •	The size, weight and quantity of
a number of large and heavy tanks         tanks required
which need to be transported to        •	Whether any special machinery
your property. The more big tanks         will required to deliver or install
required, the higher the freight and      the tanks on your property and
installation costs will be. Large,        what the costs will be

                                                                                How much
heavy tanks may also require           •	The total area required for the
more expensive machinery to lift          tanks to be installed and where
and install them. Larger tanks will       this will be on your property
also take up more space on your
property and require more spoil to
                                       •	The total volume of soil that will
                                          need to be removed from site          disposal area
be removed from site. We therefore
recommend you check:
                                          and whether the costs of removal
                                          are included in the quote.            is required?

                               16                                                               17
14                     Does the waste-      15                  Ask to see a warranty from the
                                                                supplier. Parts should be covered

                       water treatment
                                                                for at least 2 years. Performance
                                                                guarantees are rare because
                                                                performance depends largely on

                       plant need regular                       the quantity of wastewater being
                                                                treated and whether any toxic

                       desludging?
                                                                compounds enter the treatment
                                                                plant, both of which are outside the
                                                                manufacturer’s control.

All wastewater systems will need
occasional solids removal. Solids in
all types of wastewater treatment
are consolidated and decomposed,
but they do not disappear and will
eventually need removal before
accumulation begins to affect the
treatment plant operation. Check
with the manufacturer what the
                                            What are the
expected frequency and costs of
solids removal is.                          guarantees?

                               18                          19
Thank you

We hope these Guidelines         Cooks Beach Plumbing       Davies Plumbing &
for Choosing a Wastewater        & Drainage                 Drainlaying Ltd
System have been useful, and     Coromandel                 Nelson, Tasman
we wish you every success for    07 866 3189                03 544 2101
your project.
                                 Thames Drainage            Morgan Plumbing
We’ve tried to cover off the     Coromandel, Hauraki,       Marlborough, Kaikoura
most important and most          East Auckland              03 578 0060
commonly asked questions.        07 868 7004
However, if there is other                                  Foley Plumbers - Christchurch
information you would like       WH Kelly Ltd               Canterbury
to know about purchasing,        Bay of Plenty              03 343 0763
installing or operating an on    07 543 5296
land domestic wastewater                                    Kere Marshall Drainage
treatment systems, then          Opotiki Drainlayers        Canterbury
please contact us or any of      Opotiki & Whakatane        0274 359 005
our approved installers at one   07 315 6367
of the addresses below.                                     Peter Hansen Drainage
                                 Donaldson Plumbing         Canterbury
                                 Gisborne                   027 536 9331
Associated Wastewater            06 863 3688
Management Ltd                                              Menzies Group
Northland                        Lifestyle Plumbing &       Timaru, South Canterbury
09 437 2712                      Drainage                   03 684 8440
                                 Hawkes Bay
Owen Bennett Drainage Ltd        06 836 5100                Foley Plumbers - Oamaru
Northland & Kaipara                                         Oamaru
021 203 3808                     Turfrey                    0800 303 530
                                 Hawkes Bay
Laser Plumbing Warkworth         0800 182 182               All Septic & Drainage Ltd
Rodney & Kaipara                                            Otago - Dunedin
09 422 9051                      Laser Plumbing Wairarapa   03 489 4828
                                 Wairarapa, Masterton
Water FX Limited                 06 370 2259                Optum Plumbing &
West Auckland, Rodney                                       Energy Solutions
09 412 6322                      Clark Plumbing &           Queenstown Lakes,
                                 Gas Ltd                    Central Otago
WB Civil Limited                 Whanganui, Taranaki,       03 443 5718
West Auckland, Kaipara           Manawatu, Ruapehu
027 273 2311                     06 343 8953                Laser Plumbing
                                                            Invercargill
Plumbcraft                       Turfrey                    Southland
South & East Auckland            Manawatu                   027 530 4199
09 2967070                       0800 182 182
                                                            Tomasi Plumbing &
Drainage Systems Ltd             Mana Plumbing              Drainlaying
South Auckland, Waikato          Wellington, Kapiti         West Coast
07 850 4370                      04 233 8350                03 736 9715

                                                                                            Biolytix Limited
                                                                                            biolytix.co.nz
                                                                                            info@biolytix.co.nz
                                 20                                                         0800 700 818
biolytix.com
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