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KATE JANE BEECROFT
Environmental Evidence: Uruti Composting Facility Resource Consent Appeal
Expert evidence presented to the Environment Court of New Zealand regarding resource consent appeals for the Remediation (NZ) Ltd composting facility at Uruti, Taranaki. This case involves complex environmental management issues including land application of organic wastes, wastewater treatment, and contaminated site remediation.
Expert Witness Credentials
Katie Jane Beecroft, MSc
Senior Environmental Scientist at Lowe Environmental Impact with over ten years of specialized experience in organic waste management and land treatment systems.
Qualifications
  • Master of Science (Honours in Earth Sciences)
  • Bachelor of Science (Earth Science)
  • Advanced Certificate in Sustainable Nutrient Management
Professional Expertise
  • Representative for NZ Land Treatment Collective on Guidelines for Beneficial Use of Organic Materials
  • WasteMinz biosolids management strategy development
  • Contaminated site investigation and remediation planning
  • Analytical chemistry for environmental samples
Professional Memberships
NZ Society of Soil Science, Water New Zealand, NZ Land Treatment Collective
The Uruti Composting Facility
Property Size
640 hectares located in rural Taranaki, encompassing headwaters of Haehanga Stream, tributary of Mimitangiatua River
Active Operations
38.7 hectares (6% of property) used for composting, vermicomposting, and wastewater management activities
Material Processing
Approximately 8,000 t/yr for Pad 1 composting, 4,000 t/yr for Pad 2 vermicomposting, plus legacy stockpile exceeding 20,000 tonnes
The facility operates under six resource consents from Taranaki Regional Council. Two critical consents expired in May 2018, leading to renewal applications, a Council hearing, consent decline, and subsequent appeal to the Environment Court.
Site Layout and Operational Areas
01
Central Site Area & Pad 1
Main composting operations on 10,420 m² concrete pad with truckwash and collection pond. Material received via weighbridge from State Highway 3.
02
Pad 2 - Paunch Processing
10,000 m² area for receiving and dewatering paunch material prior to vermicomposting, with wetland treatment system covering 15,000 m².
03
Pad 3 - Legacy Material
15,500 m² area containing blended drilling mud stockpile and decommissioned ponds, representing significant contamination challenge.
04
Irrigation Areas
15.96 hectares available for wastewater irrigation, occupying valley bottom with mix of native and constructed soils.
All operational areas are directly adjacent to the Haehanga Stream and its tributaries, creating potential pathways for contaminant migration to surface water.
Multiple Discharge Pathways Identified
Organic Solids Discharge
Discharge of organic materials onto land within and outside wastewater catchment areas, with evidence of unauthorized placement beyond designated pads.
Leachate from Composting
Discharge of leachate from raw, partially composted, and mature compost to groundwater, eventually reaching surface water as diffuse discharge.
Pond Seepage
Wastewater seepage from truckwash, settling, and irrigation ponds to groundwater, with losses estimated at 11-110% of the site nitrogen load.
Stormwater Runoff
Both "clean" and potentially contaminated stormwater via overland flow to Haehanga Stream, with inadequate separation and treatment.
Irrigation Discharge
Wastewater to land by irrigation, with potential for groundwater leaching or surface water overland flow when mitigation strategies fail.
Wetland Discharge
Partially treated wastewater from wetland treatment system to stream tributary, proposed for cessation but lacking detailed retirement plan.
Critical Environmental Concerns
Incomplete Contaminant Accounting
Predicted distribution, transport, and loss of contaminants likely underestimated. Missing data includes seepage and breakout from wastewater catchments, contaminants from stormwater areas containing compost products, and materials from uncontrolled storage areas. Ongoing effects cannot be accurately quantified.
Wastewater System Capacity
Existing irrigation pond undersized for retention during wet periods. Addition of Pad 2 flows (1,200 m³/year) represents 9% of pond volume, creating risk of overtopping or inappropriate irrigation when soil is saturated, resulting in contaminants entering streams.
Excessive Nitrogen Loading
Irrigation areas cannot receive additional nutrient loads from Pad 2 without increased leaching to groundwater. Historical applications exceeded 1,000 kg N/ha/yr, compared to National Environmental Standard limit of 190 kg N/ha/yr. Facility unlikely to meet proposed 400 kg N/ha/yr maximum.
Pad 3 Remediation Uncertainty
No timeline for securing 20,000+ tonne contaminated stockpile. LOSP chemicals detected in irrigation pond demonstrate ongoing risk. Diligent evaluation of remediation options needed urgently, with interim measures to prevent runoff entering wastewater treatment system.
Groundwater-Surface Water Connectivity
Preliminary Conceptual Site Model
A 2015 BTW groundwater analysis established preliminary understanding of site hydrology but remains unconfirmed. The shallow groundwater table (0.25-1.4 meters below ground) sits in clay soils overlain by porous silty loams, creating direct connectivity with the Haehanga Stream.
Groundwater velocities estimated at 0.23 m/day, though likely underestimated for upper catchment areas with steeper topography and more porous soils. The stream alternates between gaining and losing reaches depending on rainfall and groundwater levels.
Critical Data Gaps
  • Contaminant migration pathway evaluation not provided
  • Groundwater travel times and flow paths uncertain
  • Scale and duration of effects to surface water unknown
  • Recommendations to calibrate model not acted upon
0.23
Meters/Day
Estimated groundwater velocity in lower catchment areas
3
Monitoring Bores
GND 2188, 2189, 2190 installed but lacking complete construction data
11-110%
Nitrogen Loss
Estimated seepage losses from pond system as percentage of site load
Composting Operations and Pathogen Risks
1
Material Reception
Animal-origin wastes containing potential pathogens deposited at Pad 1. Previous practice of depositing into Pad 3 ponds posed high pathogen transfer risk through irrigation system.
2
Composting Process
Heat-based pathogen reduction relies on temperature and moisture monitoring. No timeframe set for blending raw materials. Risk of cross-contamination and vector attraction requires better management.
3
Wastewater Generation
Rainfall on windrows generates high-concentration leachate. Newly blended or turned windows can absorb 700mm rainfall before releasing contaminants to truckwash pond.

Pathogen Studies Concern: TRC investigations demonstrate need for improved management of pathogen-containing materials. Pond system has limited pathogen attenuation ability. Pathogen monitoring of raw and mature products would assist demonstrating safety.
Pad 2 Vermicomposting Challenges
Current Operations
Paunch material received to 10,000 m² Pad 2 for dewatering before vermicomposting. Leachate currently transferred to degraded wetland treatment system before discharge to stream tributary. Wetland treatment effectiveness reduced from design levels.
Proposed Changes
  • Cease wetland discharge to surface water
  • Reduce Pad 2 from 0.95 ha to 0.1 ha
  • Transfer leachate to irrigation pond system
  • No detailed management plan provided
Retirement of Pad 2 portion may create contaminated soil excluded from managed wastewater collection, risking high-nutrient sediment entrainment in "clean" stormwater system.
Vermicompost Bed Concerns
Beds located outside wastewater collection catchments with no observed bunds. Leachate high in ammoniacal nitrogen and organic compounds likely travels to stormwater drainage and Haehanga Stream.
"Trends in ammoniacal nitrogen measured in the Haehanga tributary suggest a discharge to the stream is occurring." - TRC monitoring evidence
No monitoring of vermicompost bed discharge conducted. Not included in site nutrient balance, providing no mechanism to detect and assess effects.
The Pad 3 Legacy Problem
1
2
3
4
5
1
20,000+ Tonnes
Contaminated drilling mud and unsuitable materials accumulated over time
2
LOSP Chemicals
Timber treatment chemicals including permethrin, tebuconazole, propiconazole detected in irrigation pond
3
Treated Sawdust
Copper, chromium, arsenic contamination from timber treatment chemicals, baled but not removed
4
Decommissioned Ponds
Two ponds filled without NESCS compliance evaluation, approximately 250 m³ excavated material
5
Ongoing Risk
Ponding observed around stockpile following rainfall, leachate potentially entering irrigation system
Robust characterization completed by PDP, but no remediation timeline established. Material continues posing environmental risk. Urgent evaluation of remediation options needed with interim measures to prevent runoff entering wastewater treatment system.
Wastewater Treatment System Analysis
01
Truckwash Pond
Collects contaminated stormwater from Pad 1 via sheet flow plus truck washout water. Contains organic compounds, nutrients, pathogens, and solid materials. Requires aeration to avoid odour issues.
02
Settling Pond
Receives transfer from truckwash pond, located on Pad 3. Shares aerator with truckwash pond. Biocides including LOSP chemicals detected, potentially impacting biological treatment processes.
03
Irrigation Pond
Final treatment stage with approximately one month retention time. System likely undersized for both treatment and storage during wet periods when irrigation cannot occur.

System Capacity Concerns: Pond levels vary through year with uncertain aerator operation under all conditions. Storage volume inadequate for soil moisture-based irrigation management, risking pond overtopping or inappropriate irrigation during saturated soil conditions.
Irrigation Area Performance and Limits
1,200
kg N/ha/yr
Peak historical nitrogen application rate to irrigation areas
500+
kg N/ha/yr
Recent application rates across six of eight irrigation areas
400
kg N/ha/yr
Proposed maximum nitrogen leaching rate unlikely to be achieved
190
kg N/ha/yr
National Environmental Standard for Freshwater limit for comparison
Irrigation Management
15.96 hectares available for wastewater irrigation using soil moisture-based timing. Cut and carry pasture system removes nutrients when baleage or silage exported from property. Small moveable irrigators replacing travelling irrigators should reduce groundwater losses.
Contamination Concerns
Chloride triggers frequently exceeded. LOSP chemicals from treated sawdust likely accumulated in irrigated soils. Detailed investigation needed across site. No evaluation of long-term impacts on soil and plants for newly identified contaminants.
Site Nutrient Balance Uncertainties
Missing Wastewater Sources
Seepage and breakout from ponds not fully accounted. Historical concentrations not reflected in loading calculations. Additional nutrients from Pad 2 integration not adequately assessed.
Stormwater Contamination
Contaminants from areas containing compost and vermicompost products not evaluated. Inadequate separation between clean and contaminated stormwater systems.
Uncontrolled Storage Areas
Materials deposited outside designated pads. Contaminated fill used for land development. Approximately 4,400 m² area between Pad 1 and vermicompost beds containing covered mature compost.
Stockpiled Material Impacts
Pad 3 stockpile contributions to nutrient balance uncertain without removal or isolation plan. Legacy contamination continuing to impact irrigation pond quality.
Total site nitrogen loss likely underestimated. Effects of discharge inadequately assessed despite activities occurring near surface water paths with reduced attenuation opportunity and short groundwater travel distance.
Expert Evidence Responses
Agreement with TRC Evidence
Generally concur with Gary Bedford and Dr. David Horne's assessments. Strongly agree management plans should be finalized and audited before allowing further waste receipt or continuing operations. Current detail insufficient to conclude effects can be avoided, remedied, or mitigated.
Concerns with RNZ Evidence
Mr. Irvine's Pad 2 reduction from 1.0 ha to 0.1 ha requires demonstration of feasible layout. Mr. Kay's nitrogen uptake assumptions (15 t/ha) likely unachievable at this location. Ms. Webster's assertion Pad 3 poses no immediate risk disputed given LOSP detection in irrigation pond.
Stormwater Management Gaps
Disagree with Mr. Easton's assertion stormwater is controlled across site. No evaluation of areas, volumes, or contaminants beyond silt provided. No comprehensive site map showing catchments and treatment devices. Contaminants beyond sediment likely discharging to streams.
Data and Monitoring Deficiencies
Disappointing lack of site-specific monitoring data for system operating this long. Pad 2 leachate quality predicted rather than measured. Temperature and moisture data for composting process not reviewed. Pathogen monitoring of products would demonstrate safety.
Conclusions and Professional Opinion
Insufficient Confidence in Mitigation
Proposed activities rely on management plans not submitted for review. Lack of detail regarding future site management creates high uncertainty. No confidence that RNZ can remedy or mitigate effects due to unclear site design and poor operational description.
Incomplete Environmental Assessment
Contaminant migration pathways not evaluated. Groundwater conceptual site model remains unconfirmed since 2015. Connectivity between shallow groundwater and Haehanga Stream demonstrated but travel times and flow paths uncertain. Impact assessment incomplete.
Multiple Unresolved Issues
No limit on material volume allowed on site. History of unauthorized waste deposits. Contaminated sawdust baled but not removed. Comprehensive site characterization needed to determine location, extent, and composition of materials around site.
Urgent Actions Required
Pad 3 remediation evaluation needed as matter of urgency. Detailed investigation of LOSP and other contaminants across irrigation areas required. Stormwater Infrastructure Management Plan development essential. NESCS compliance evaluation for pond decommissioning work needed.
"I do not have confidence that RNZ can remedy or mitigate effects due to the site operation on the basis of the evidence provided." - Katie Jane Beecroft, MSc