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Inside this issue:
Update from NZLTC Chair and
Technical Manager
1
NZLTC 2020 Conference 2-3
Onsite Wastewater Management
Systems (OWMS) workshop
4-5
Department of Conservation:
Waste management on a Great
Walk
6
The Darfield Onsite Wastewater
Management Story
7-8
Managing stormwater on land to
protect surface water 9
NZLTC Resources - Northwest
Biosolids 10-11
NZ Land Treatment Col lect ive
NEWSLETTER
Dedicated to improving and communicating research and technology for the land treatment of waste
Kia ora everyone
Preparations for our annual NZLTC conference are in full swing! The NZLTC Technical
Committee are really looking forward to reconnecting with the wide range of
conference delegates that attend every year. The
conference always provides a ‘boutique’ experience for
our land treatment community where networking
opportunities are plentiful alongside an atmosphere of
camaraderie within our small group. We encourage you
to register and take advantage of the opportunity to
connect and learn. For the registration link please click
here.
We are pleased to announce that Dr Mark Borchardt from the US Department of
Agriculture has been confirmed as our International keynote speaker. Mark is an
excellent communicator and his research includes septic system
wastes and land applied livestock manure as related to pathogen
contamination of groundwater and human health risks. His keynote
address will be highly relevant to the many land treatment
challenges that NZ faces.
This newsletter contains information on:
NZLTC annual conference 31 March—2 April 2020 Palmerston North (page 2-3)
Onsite Wastewater Management Systems (OWMS) workshop 30 March 2020 Palmerston North (page 4-5)
Department of Conservation - Onsite waste management challenges (page 6)
The Darfield Onsite Wastewater Management Story - Canterbury (page 7-8)
Managing stormwater on land (page 9)
Northwest biosolids resources: cannabis and nitrous oxide (page 10-11)
Ngā mihi nui
Grant Northcott (NZLTC Chair) and Bronwyn Humphries (NZLTC Technical Manager)
Update from the NZLTC Chair and Technical Manager
I ssue 64
Newslet ter Feb 2020
https://nzltc.wordpress.com/
1
The Routeburn Track one of New Zealand’s Great Walks - On-site Wastewater Management System (OWMS) at Routeburn Falls Hut
2
Monday 30 March Tuesday 31 March
General land treatment and
OWMS focus
Wednesday 1 April
General land treatment and
agricultural focus
Thursday 2 April
Workshop
On-site Wastewater
Management (OWMS)
- all key stakeholders to dis-
cuss what is working and what
isn’t
- progress a plan for the future
Conference - Day 1
International keynote -
Mark Borchardt (USDA)
Local keynote - Hori-
zons Regional Council
National keynote - TBC
Delegate presentations
Conference - Day 2
National keynote - TBC
Delegate presentations
Fieldtrip
Palmerston North - land
treatment locations
Evening Events
Social function
Brew Union Brewing
Company (craft beer,
pizza and spot prizes)
Conference dinner and
awards
TBC
Premier sponsors
Break sponsor Award sponsor
Northcott Research
Consultants Ltd.
Student Scholarship sponsor
Lunch sponsor
3
Trade Displays
The NZLTC are inviting exhibitors to purchase a trade display area. This is an ideal opportunity to showcase your business
and land treatment technologies.
sites are $500 each
10 sites available
Contact Bronwyn Humphries (NZLTC Technical Manager) to secure your site
bronwyn.humphries@esr.cri.nz
Important dates
Registrations and abstracts are now open
Abstracts close - 21 Feb 2020
Authors notified—28 Feb 2020
Full papers due - 25 Mar 2020
OWMS Workshop - 30 Mar 2020
NZLTC AGM - 31 Mar 2020
NZLTC Conference - 31 Mar - 2 Apr 2020
Sponsorship To view our conference sponsorship opportunities click here:
International Keynote
Dr Mark Borchardt is a microbiologist who works for the US Agricultural Department (USDA) in
Wisconsin.
His research includes septic system wastes and land applied livestock manure as related to pathogen
contamination of groundwater and human health risks. mark.borchardt@usda.gov
Venue accommodation rates
To view options click here:
Online conference registration click here:
Key conference information
NZLTC AGM
The NZLTC AGM will be held at the Distinction Coachman Hotel, Palmerston North at 4:30pm, Tuesday 31 March 2020
NZLTC Social Evening - Tuesday 31 March
The social evening will be held at the Brew Union Brewery. Names will be collected via business cards during the evening
and the event sponsor will draw out winners for some quality prizes plus a few humorous ones.
All stakeholders
On-site Wastewater Management Systems
(OWMS) workshop
Monday 30 March 2020
9:30am – 4:30pm
Distinction Coachman Hotel
Palmerston North
Brought to you by:
Small Wastewater and Natural Systems - Special Interest Group (SWANS-SIG)
and
NZ Land Treatment Collective (NZLTC)
Purpose: For stakeholders to identify core OWMS issues in New Zealand
(i.e what’s working and what isn’t)
Outcomes:
1) Document outlining the OWMS issues as identified by each sector
2) Create a network of key stakeholders to be involved in future discussions
3) Set the agenda for a second workshop in the future to help address some of the issues
Format: Specialists from each industry sector have been invited to make 15 min presentations focused on
core OWMS issues followed by 10 mins Q and A.
For more information please contact:
Joint SWANS-SIG Chairs
Sandy Ormiston sormiston@ormiston.co.nz
Trisha Simonson tsimonson@ormiston.co.nz
NZLTC Technical Manager
Bronwyn Humphries bronwyn.humphries@esr.cri.nz
WaterNZ member: $60
NZLTC member: $60
Other: $120
Register online: Click here
If you are a WaterNZ member please
get in touch with:
bronwyn.humphries@esr.cri.nz for the
discount code
4
5
Welcome to Workshop and Outline of Objectives
9:30-9:45 Sandy Ormiston
Industry Sector: Designers
9:45-10:00 Andrew Dakers (Eco-Eng)
10:00-10:15 John Cocks (John Cocks Limited)
10:15-10:25 Questions/Discussion
10:25-10:45 Morning Tea
Industry Sector: System Suppliers
10:45-11:00 Brent Hawthorn (Innoflow Technologies)
11:00-11:15 Mike Dawson (Hynds)
11:15-11:25 Questions/Discussion
Industry Sector: Installation and Maintenance
11:25-11:40 Craig Rall (Envirolutions)
Industry Sector: Irrigation
11:40-11:55 Bruce Richter (Netafim)
11:55-12:05 Questions/Discussion
Industry Sector: Regulators
12:05-12:20 Keith Peacock (Hawkes Bay Regional Council)
12:20-12:35 Leif Piggott (Tasman District Council)
12:35-12:45 Questions/Discussion
12:45-1:25 Lunch
Industry Sector: OSET-NTP
1:25-1:40 Ray Hedgland (OSET Technical Manager)
Industry Sector: Training
1:40-1:55 Brett Marias (WSP Training)
Industry Sector: End-User
1:55-2:10 Peter Carter (Department of Conservation)
2:10-2:20 Questions/Discussion
Industry Sector: Research
2:20-2:35 Malcolm McLeod (Landcare Research)
2:35-2:40 Louise Weaver (ESR)
Industry Sector: Public Health
2:40-2:55 John Whitmore (ADHB)
2:55-3:05 Questions/Discussion
3:05-3:25 Afternoon Tea
Water Industry Regulatory Reform
3.25 – 3.35 Noel Roberts (WaterNZ)
3.35 - 3.45 Questions/Discussion
Identification of Key Issues – Group Discussion
3:45-4:15 Sandy Ormiston/Trisha Simonson/Bronwyn Humphries
Closing Comments/Way Forward
4:15-4:30 Sandy Ormiston
6
Department of Conservation: Wastewater Management on a Great Walk
Great Walks provide an iconic wilderness experience in New Zealand
and attract hundreds of thousands of visitors each year. Huts pro-
vide accommodation for visitors who spend a day or more on a walk.
Many people visit as day trips. Wastewater management at huts and
elsewhere on walks provides special challenges. We outline some of
these.
Visitor numbers. There are 36 great walk huts, with hut bunk num-
bers varying from about 57 (Lake Mackenzie Hut on the Routeburn
Track) to less than 20. At some remote locations, the bunk number
is a reliable design occupancy. Other huts have day walk visitors,
and their numbers can be 10 times or more the bunk number. There
are also often campsites associated with the great walk huts. Bunk
booking is required for overnight visitors and records provide reliable
overnight visitor numbers and patterns. Day visits fluctuate depend-
ing on time of year, weather, condition of the track and media arti-
cles. Numbers are not necessarily predicable.
Physical environment. Great Walks are where nature is spectacular
or otherwise exceptional: steep mountains, dense forest, high tus-
sock lands, coastal bays. Some places have high rainfall, snow and
extreme weather events. Often the topography is steep, rocky, or
swampy, and soil cover is shallow. Access is by foot, helicopter or, in
some cases, boat.
Construction logistics: Construction at these remote sites requires
exacting coordination, flexibility and cooperation by all parties. Fick-
le weather patterns, unexpected obstacles and additional material
or skill needs can result in major disruptions or significant additional
cost. Construction is usually by a few contractors with experience in
remote locations and materials and contractors are generally flown
in. Helicopter costs can range from $100k to over $300k for a large
hut development.
Peter Carter (DOC) and John Cocks (JCL)
Devil’s Staircase Tongarira Crossing Mangatepopo Hut Toilet
Forest (left) and rocky terrain (right)
Operational logistics: Typically, huts have wardens during the
walking season. Their duties are multiple and include looking
after wastewater systems. Preferably, systems require minimal
day to day attention or specialist training to operate. Wastewater
discharge occurs over short periods, when walkers arrive at a hut
or prepare to leave early in the morning. A stable, robust and
reasonably simple treatment process that accommodates such
peaks is needed. Typically this is a septic tank type system with
gravity discharge, although some systems include pumping by
solar or petrol pumps. Sludge needs routine removal by helicop-
ter or boat. Regulations inhibit or prevent discharge at on-site.
On the southern great walks, the wastewater systems are decom-
missioned outside of the great walk season and vault toilets are
used.
Design: Given the above constraints, reliable design requires
demanding investigations and good visitor information. Second-
ary treatment and other advanced systems need regular operator
attention or training, which poses significant risks. Conventional
or innovative land application techniques or waste removal pro-
vides public health and environmental protection.
Toilet foundation construction Tongariro Crossing
Clockwise from top left: waste flyout, manual dosing,
old septic tank, septic tank pump out.
Left to right: Waste vault toilet, solar powered pumping, above
ground LPED
Materials delivery (left) and toilet delivery on the Tongariro
Crossing (right)
7
The Darfield On-site Wastewater Management Story Rob Potts (Lowe Environmental Impact) Lee Burbery (ESR)
Darfield is a rural township in the Selwyn District, located to-
wards the top of the Canterbury Plains. It sits atop of an exten-
sive unconfined alluvial gravel aquifer that is the regions princi-
pal freshwater drinking water resource. The town holds the
ignominious title of being the septic-tank capital of New Zea-
land – the resident population is in excess of 2,000 and effec-
tively all households operate an on-site wastewater manage-
ment system (OWMS). Community and Public Health (CPH), and
Selwyn District Council (SDC) have long harboured concerns
regarding the sustainability of wastewater management prac-
ticed in the town and the hazard it presents to human health.
As a knock-on effect of the Christchurch earthquakes of 2011,
the town experienced rapid population growth that was not
forecast and which revived interest in assessment of the
wastewater management status. In 2014, the Ministry of
Health (MOH) commissioned a review of the hazard that the
current wastewater discharge practice in Darfield [and Kirwee]
poses to the underlying groundwater resource.
Key points from the report are (Burbery, 2014):
Darfield is the largest town in NZ with no centralised
wastewater management system.
Groundwater in the underlying aquifer is heavily utilised
as a freshwater resource, including serving as the main
source of [untreated] drinking water.
It is perceived that the almost 80 m thick vadose zone
underneath the town provides an effective buffer to
contamination of the groundwater from microbiological
contaminants discharged via OWMs. That said, within
the district, Escherichia coli has on occasion been de-
tected in groundwater sampled from wells screening
125 m below ground level. This suggests the aquifer is
not entirely immune from microbial contamination origi-
nating from land-based practices.
Nitrate is the primary groundwater contaminant of con-
cern associated with discharges from OWMS’s at Dar-
field. Nitrate concentrations in the treated effluent
plume beneath the township are conceived to be in the
order of 65 mg NO3-N/L.
Subsurface conditions are not conducive to any natural
attenuation of nitrate and dilution of any groundwater
pollution in the locality is limited owing to the proximity
to a geological boundary of the Canterbury Plains aqui-
fer system.
At the current housing density, nitrogen loadings from
the township to the groundwater resource are unlikely
to be much different from loadings from the surround-
ing agricultural land-use.
Key future issues for Darfield:
The benefits of a concentrated land application site with
high level treatment versus well-functioning and main-
tained multiple on-site discharges over a large area.
The Canterbury District Health Board conducted a sur-
vey of Darfield wastewater management systems in
2014 and found that many systems were poorly operat-
ed and maintained. More than 100 systems were sur-
veyed and found fewer than 10% of residents did regu-
lar service or maintenance. Many residents had poor
knowledge of their on-site systems and about a third
had not had their tank emptied in the last 5 years. Near-
ly 1 in 3 systems had some kind of failure. Survey Re-
port click here.
Key future issues for Darfield: continued
The older parts of Darfield are small sections with many
of the OWMS discharging via gravity seepage to
soakholes, as under the Transitional Regional Plan
(TRP), soak pits in Darfield were a permitted activity
provided certain conditions were met. Under the LWRP
these can continue to be used as long as they were
lawfully established prior to 1 November 2013 and
provided there have been no changes to the system or
increases in volumes discharged.
Darfield has an older than normal demographic, with
many farmers retiring to the area. In addition, due to its
distance from Christchurch, it is also seen as a less
expensive housing area. This means that there is less
enthusiasm for a reticulated system, with many
vehemently opposed to having to spend another
$25,000 per household for a scheme. However, at the
same time, many see the lack of the community sewer-
age system as holding back development of Darfield.
Subdivisions are still occurring, with section sizes
ranging from 450 m2 to 0.5 ha. Their OWMS are costing
between $10,000 and $25,000.
Stantec (2016) have undertaken a high level option assess-
ment for Darfield. Levels of treatment assessed were:
1) High Tech – Activated sludge plant (ASP) with Biological Nutrient Removal (BNR);
2) Medium Tech – lowly loaded Trickling Filter (TF) plant; and
3) Low Tech – Waste stabilisation Pond (WSP) or oxidation pond.
Each of the above methods has different amounts of N removal
which results in different amounts of area being required to
apply the effluent to land ranging from 21 ha to 90 ha. Capital
costs for reticulation and the treatment plant are in the order of
$19,000 – 25,000/lot based on 2041 population estimates. A
possible option is to just connect the central business part of
the town (includes 2 hotels, 2 cafes and a bakery and a butch-
er) and the older and smaller sections to get a scheme started.
The recommendation that was put forward was Option 3, the
waste stabilisation pond for the treatment facility. This is due to
the following advantages:
Lowest capital cost/investment – WWTP;
Lowest NPV (excluding consideration of land that is already owned);
Ability to stage development; and
Lowest operating cost (operator input/energy costs).
Lee
Rob
8
The Darfield On-site Wastewater Management Story - continued
The network options to convey the wastewater to the WWTP
considered were:
1) Gravity sewer – decommission septic tanks, direct con-
nection to gravity sewer reticulation;
2) Low pressure sewer system – decommission septic
tanks, install new pump pot, connect to pressure reticu-
lation;
3) STEP system – reline septic tank, install new pump pot,
connection effluent sewer reticulation;
4) Vacuum sewer system – decommission septic tank,
gravity connection to pot in berm, connection to vacuum
reticulation.
The option that was recommended was Option 2, the low-
pressure sewer system. This is the preferential option due to
the benefits listed below:
Over-riding factor of seismic resilience;
Lower ongoing operation and maintenance costs com-
pared to vacuum systems;
Flexibility associated with alignment and installation
depth; and
Fewer constraints for future connections.
Nitrogen Leaching Assessment:
Loe (2013) provided the technical s32 report to support setting
nitrogen loading (leaching) limits in the Canterbury Regional
Council’s Land and Water Regional Plan (LWRP). He used 9 kg
loading per primary treatment system (septic tank) and 3 kg
per secondary treatment system and assumed all new builds
post 2006 were secondary – this gave 56 t N/yr in the Selwyn
Waihora Zone. Within Darfield, pre-2006 was approximately
1,100 people and post-2006 an additional 2,000 people. At
2.5 people/household, this equates to 440 houses pre and
another 800 post-2006
The assumptions in the Loe report regarding secondary sys-
tems post 2006 is not correct, with many primary systems still
being installed with LPED discharge systems. For the purposes
of this assessment, it is assumed that 50% following 2006 are
secondary with SDI and 50% primary and LPED.
Basic Calculation: 3000 people at 2.5 per house and 200 L/p/
d is 500 L/d/household. Nitrogen following a primary system is
in order of 50 mg/L with say no reduction in the LPED system,
and secondary systems nitrogen in the order of 30 mg/L with
reduction in the SDI land treatment area due to plant uptake,
microbe use and denitrification of say 30%. Therefore a prima-
ry system leaches approximately 9 kg N/yr/household (same
as Loe calculation), and the secondary system 4 kg N/yr/
household. This equates to 9,160 kg N/yr into the aquifer sys-
tem from Darfield’s on-site systems.
So how does this compare to agriculture? The LWRP allows 15
kg N/ha/yr from farming in this nutrient sensitive zone, so
9,160 kg N/yr is equivalent to 610 ha of allowable farming.
Also, how different would it be if there was a community
scheme?
And how different would it be if there was a community
scheme. Selwyn District Council has a 142 ha block of land on
the south-eastern side of Darfield that was purchased specifi-
cally for a future sewage scheme – this is a great start (Figure
1). Assuming a wastewater treatment plant producing 30 mg/
L nitrogen, irrigating to the SDC land with a cut and carry
landuse, then the 9,160 kg N/yr leaching would be reduced to
around 1,300 kg N/yr leached, based on N loading being
matched to N removed in herbage but winter drainage still re-
sulting in leaching. Equates to 90 ha of allowable farming.
However, the main advantage of a community scheme from an
environmental risk point of view is the centralised operation
and management, with on-going maintenance, as well as moni-
toring performance and the environment.
What Does the Future Hold?
Kicking off a community scheme did not make Selwyn District
Council’s LTP, so the earliest that a Council promoted scheme
may occur would be 2034.
A private plan change has been lodged with Council that has
over 100 sections and an Aged Care Facility in Stage 1 and
another 900 lots in a future deferred zone. This was not con-
sidered favourably by the Health Board and they opposed it.
Fortunately the developer is forward thinking and has proposed
a full reticulated system and a community WWTP system and
LTA for their development. Unfortunately this is on the oppo-
site side of Darfield to the Council site, so the developer has
set aside an additional 6 ha site for treatment and land treat-
ment, along with a short term consent that will hopefully kick
start a community scheme for all or at least the core commer-
cial areas of Darfield and future development.
Figure 1: SDC Owned Farm for Sewage Scheme
Figure 2: Darfield business zones, existing B1 zone (green) and ex-
panded B1 zone (yellow)
References:
Burbery, L. (2014). The potential hazard on-site wastewater
treatment systems in Darfield and Kirwee present to local
groundwater quality and critique of current assessment meth-
ods. Prepared as part of a Ministry of Health contract for sci-
entific services. Client report FW 14004. Christchurch: Insti-
tute of Environmental Science and Research Limited.
Loe, B, February 2013. Selwyn- Waihora Catchment. Estimat-
ing nitrogen and phosphorus contributions to water from dis-
charges of sewage effluent, from community systems, and
milk processing wastewater. Environment Canterbury Report
No, R13/8.
Stantec, March 2016. Darfield Wastewater Strategy. Pre-
pared for Selwyn District Council.
lee.burbery@esr.cri.nz
rob@lei.co.nz
9
Managing stormwater on land to protect surface water
Robyn Simcock - Manaaki Whenua Landcare Research
Stormwater is a valuable resource, but can also degrade
surface waters, especially when it collects contaminants,
and cause erosion or flooding. At the 2018 NZLTC con-
ference in Rotorua Brian Levine (NZLTC Student Scholar-
ship recipient) reported promising results from the Phos-
phorus Mitigation Project. A detainment bund that
trapped stormwater runoff from high-producing pasture
for 3 days before being released, greatly reduced P, N
and sediment. Variations on this method of protecting
waterways by slowing, detaining, infiltrating and evapo-
rating runoff have been used in cities and roadsides;
engineered swales, bioswales and raingardens have pro-
liferated throughout New Zealand since ‘TP10’ (2003)
and ‘TP124’ (2000) were produced by Auckland Regional
Council to guide management of stormwater runoff.
These technologies are a core part of ‘Water Sensi-
tive’ (Urban), ‘Low Impact’ or ‘Sustainable’ Urban Design
(acronyms WSUD, LID or SUDs).
Experience in our cities over the last 20 years has helped
design and integrate these stormwater treatment devic-
es in ways that deliver more value for money and cost
less to maintain. These technologies are still not yet
mainstream in New Zealand. However, the National Poli-
cy Statement for Freshwater Management is likely to be
a key driver, especially as passing storm water through
plants and soil aligns closely with kaitiaki values and
complements design through a te ao Māori lens.
Last year, New Zealand and international learning was
summarised in a series of free, web-based resources on
the “Activating Water Sensitive Urban Design’ website,
funded by the ‘Building Better Homes, Towns and Cities
National Science Challenge. They can be accessed here
link. The resources include:
Case studies and ‘WSUD walks’ in Auckland,
Christchurch and Queenstown lakes
Understanding costs and maintenance
Assessing the full benefits, and ‘More than Water’
assessment tool
Te Ao Māori and WSUD
Incentives and funding
Unlike pipes and other ‘hard infrastructure’ WSUD can
help celebrate stormwater and enhance receiving waters
and where we live, not just treat or dispose stormwater.
Both rural and urban areas have many opportunities to
better manage stormwater, and these resources should
help.
From left to right: raingardens Wynyard Quarter (Auckland); mown swale with trees in Stoke; no-mow swale in
Manurewa Botanic Gardens; roadside raingarden in central Christchurch
simcockr@landcareresearch.co.nz
10
NZLTC Resources
The NZLTC is a member of Northwest Biosolids (University of Washington). Northwest Biosolids provide its members with
exclusive access to up-to-date biosolids research and online resources. These resources are available on the NZLTC members
only portal as a mix of abstracts and full papers. https://nzltc.wordpress.com/members-area/northwest-biosolids-resources/
The latest Northwest Biosolids December and January library focus is on:
- Cannabis
- N2O (Nitrous oxide)
If you are a member and have forgotten the members only password or would like more information about becoming an
NZLTC member to gain access to these resources please contact the NZLTC Technical Manager
bronwyn.humphries@esr.cri.nz
https://nwbiosolids.org/
Title: Legal cannabis laws, home cultivation, and use of edible cannabis products: a growing relationship?
Author: Borodovsky, J.T. and A.J. Budney
Source: International J. Drug Policy 2017 50: 102-110
Title: The quasi-legal challenge: assessing and governing the environmental impacts of cannabis cultivation in the North
Coastal Basin of California
Author: Short Gianotti, A.G., J. Harrower, G. Baird, S. Sepaniak
Source: Land Use Policy 2017 61: 126-134
Title: The carbon footprint of indoor cannabis production
Author: Mills, E.
Source: J. Environ. Qual. 2003 32: 100-108
Title: The benefits of growing cannabis with compost
Author: Samuelson, P
Source: Cannabistraininguniversity.com 2019
Title: The genesis of a critical environmental concern: Cannabinoids in our water systems
Author: Saleh, N.B., O. Apul, T. Karanfil
Source: Environ. Sci. Tech. 2019 53: 1746-1747
Approximately 192 million people worldwide aged 15−64 (i.e., 3.9% of the global population, per 2016 estimates) regu-
larly use Cannabis, more commonly known as marijuana. The estimated market share of this widely used drug will sur-
pass $22 billion by 2022. On June 28, 2018, the United States Food and Drug Administration approved Epidiolex, a can-
nabinoid-based drug developed for the treatment of a rare form of epilepsy. Unfortunately, despite their widespread avail-
ability, un- certainty-in-point and mass production projections, adverse effects on the nervous system and increased
pharmaceutical use, cannabinoids remain the most understudied class of ECs within aquatic systems. The transfor-
mation of these products, which are often more toxic than the parent compounds, encourages understanding the reac-
tion processes that cause their development. Indeed, new organic contaminants or ECs that are created by the transfor-
mation processes in water and wastewater systems have been detected in waste and surface waters, which means that
treatment processes must evolve accordingly. Halogenated methanesulfonic acid (HMAs), a new class of organic mi-
cropollutant produced from an approved drug, is now prevalent in the water cycle and is one of the latest addition to the
EC list. As with HMAs, cannabinoids will likely introduce similar compounds during their passage through engineered
treatment systems.
Cannabis
NZLTC Technical Manager
Bronwyn Humphries
bronwyn.humphries@esr.cri.nz
nzltc@esr.cri.nz
NZLTC Finance and Administration Management
Robyn Chapple
robyn@lei.co.nz
11
NZLTC Contacts
Important dates
2019/2020 NZLTC Memberships due
NZLTC Conference abstracts close 21st Feb
SWANS-SIG / NZLTC Workshop 30 March
Palmerston North
NZLTC Conference 31 March - 2 April
Palmerston North
NZLTC AGM 2 April 2020 Palmerston North
NZLTC Technical Reviews -
members only
In the next few months two NZLTC technical review
documents will be made freely available to our
members only. The topics are:
Managing disease outbreaks and the
implications for land treatment: focus on
Mycoplasma bovis
Microplastics in New Zealand Waste Water
Treatment Plants (WWTPs) and the implications
for land treatment If you wish to become an NZLTC member to gain access
to these documents please contact Bronwyn
Humphries.
Title: Global nitrous oxide emission factors from agricultural soils after addition of organic amendments: a meta-analysis
Author: Charles, A., P. Rochette, J.K. Whalen, D.A. Angers, M.H, Chantigny and N. Bertrand
Source: Ag. Ecosys. Environ. 2017 236:88-98
Title: Nitrous oxide emissions respond differently to mineral and organic nitrogen sources in contrasting soil types
Author: Pelster, D.E., M.H. Chantigny, P. Rochette, D.A. Angers, C. Rieux and A. Vanasse
Source: J. Environ. Qual. 2012 41: 427-435
Title: Effects of organic and inorganic fertilizers on greenhouse gas (GHG) emissions in tropical forestry
Author: de Urzedo, D.O., M.P. Ranco, L.M. Pitombo, and J. Braga do Carmo
Source: Forest Ecol. Manage 2013 310: 37-44
Title: Soil nitrous oxide emissions from agricultural soils in Canada: Exploring relationships with soil, crop and climate
variables
Author: Rochette, P., C. Liang, D. Pelster, O. Bergeron, R. Lemke, R. Kroebel, D. MacDonald, W. Yan, C. Flemming
Source: Agric. Ecosys. Environ. 2018 254: 69-81
National scale emissions of nitrous oxide (N2O) from agricultural soils are often estimated using a unique fer- tilizer-
induced emission factor (EF); thereby neglecting how factors other than nitrogen input could impact emissions. In the
present study, we compiled soil N2O flux data collected since 1990 on agricultural soils in Canada, to identify key soil
and climate factors, and management practices that explain variations in N2O emissions and in EF. Stepwise regression
analysis showed that the growing season precipitation was the most important factor impacting N2O emissions, and that
cumulative N2O fluxes and EFs could be predicted using equations (R2 from 0.68 to 0.85) including two to five of the
following variables: growing season precipitation, ratio of growing season precipitation to potential evapotranspiration,
mean annual air temperature, crop type (annual or perennial), soil pH, texture and organic carbon content. We conclude
that N2O EFs could be effectively stratified based on growing season precipitation, soil texture (coarse, medium and fi-
ne), type of N (synthetic and organic), and crop type (perennial and annual). We propose EFs that account for the domi-
nant factors that modulate the nitrogen fertilizer-induced emissions and should improve regional and national estimates
in Canada. They may also provide useful information for guiding the development of soil N2O emission quantification in
other countries.
Title: Nitrous oxide emissions from clayey soils amended with paper sludge and biosolids of separated pig slurry
Author: Chantigny, M.H., D.E. Pelster, M.H. Perron, P. Rochette, D.A. Angers, L.E. Parent, D. Masse, and N. Ziadi
Source: J. Environ. Qual. 2013 42:30-39
N2O - Nitrous oxide
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