Bell Island WWTP NRSBU Mission Statement To identify the long term - - PowerPoint PPT Presentation

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Bell Island WWTP NRSBU Mission Statement To identify the long term - - PowerPoint PPT Presentation

Sep 24, 2022 482 likes •963 views

Bell Island WWTP NRSBU Mission Statement To identify the long term wastewater processing and reticulation needs of our customers and to meet current and future needs in the most cost effective and sustainable manner. Regional sewage treatment

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Bell Island WWTP

NRSBU Mission Statement To identify the long term wastewater processing and reticulation needs of our customers and to meet current and future needs in the most cost effective and sustainable manner.

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Regional sewage treatment

  • 1970 – Stoke Sewage Treatment Plant upgrade
  • ptions
  • Investigations suggested increasing scope of

catchment

  • 1974 – Nelson City and Waimea County worked on

regional facility

  • Bell Island chosen as site
  • 1981 - Formal Agreement signed for regional

facility

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1983

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1993 upgrade 1993 upgrade 1993 upgrade 1993 upgrade

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1993 to 1996: Remove sludge from ponds to reinstate 1993 to 1996: Remove sludge from ponds to reinstate 1993 to 1996: Remove sludge from ponds to reinstate 1993 to 1996: Remove sludge from ponds to reinstate treatment capacity and improve odour management treatment capacity and improve odour management treatment capacity and improve odour management treatment capacity and improve odour management

  • Mechanical mixers deployed in the ponds in 1993.
  • Sludge removal from the facultative ponds.
  • Sludge removed from the ponds were applied to

land at Bell Island.

  • Conditions improved but further odour issues

developed over time.

  • The original aeration basin was found to be the

source of odours.

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2004 upgrade 2004 upgrade 2004 upgrade 2004 upgrade

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2006 Capacity Review

  • Population and Industrial growth to 2025
  • Flow and Load projections
  • Upgrade designed to match projections
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2010 Treatment Plant Upgrade

  • Inlet structure with screens
  • Primary Clarifier
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Replacement Value = $75 to 80 Million

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Why does the NRSBU treat wastewater

  • To protect public health and minimise impacts on

environment

  • Separate and reduce solids
  • Reduce organic materials
  • Reduce pathogens
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Bell Island Wastewater Treatment Plant Process Diagram

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Maturation and Facultative Ponds

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Dr Rob Lieffering – Senior Environmental Consultant Client: Nelson Regional Sewerage Business Unit (NRSBU) Date 14 June 2017

Resource Consent Renewal Bell Island Wastewater Treatment Plant

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Agenda

2 Existing resource consents - Overview 3 Regulatory framework 4 Assessment of Environmental Effects - Studies 5 Sensitive sites 1 Project Objectives

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Project Objectives

  • 1. To work with the community, key stakeholders, and tāngata

whenua to ensure a wastewater treatment and disposal solution that:

  • Provides for current and future community well-being,

health and safety

  • Ensures acceptable environmental and cultural effects
  • Provides for planned future population and

industrial/commercial growth

  • Achieves efficient use of existing infrastructure
  • 2. Obtain long term consents that provide certainty for future

growth and security for ongoing investment in the infrastructure

  • 3. Provides a solution that is the Best Practicable Option (RMA

definition) for the treatment and disposal of the wastewater.

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Overview – Existing Consents

Four Consents Cover WWTP Operations Consents to be renewed:

  • Discharge treated wastewater to Waimea Inlet
  • Discharge treated wastewater to land (irrigation)
  • Discharge contaminants (odour) to air from WWTP

Consent not being renewed

  • Discharge biosolids to Rabbit Island
  • Doesn’t expire until November 2020
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Overview – Existing Consents

Additional Consents

  • Seepage from unlined parts of WWTP to land

(oxidation ponds) – technically a discharge to land

  • Outfall diffuser structure – coastal permit for

structure within the Coastal Marine Area (CMA) These were included in earlier application but consents were not specifically granted for these. Now seeking to formally authorise these.

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Overview – Existing Consents

Discharge treated wastewater to Waimea Inlet Consent Limits – Timing:

  • Discharge may only occur for up to 3 hours

following high tide – intention that treated wastewater leaves Waimea Inlet during each tidal cycle

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Overview – Existing Consents

Discharge treated wastewater to Waimea Inlet Consent Limits – Rates:

  • Average daily discharge <20,000 m3/day
  • Maximum daily discharge <25,000 m3/day
  • Olympic swimming pool holds ~2,500 m3
  • Eastern arm of Waimea Inlet has an estimated

tidal volume in the order of 40-50,000,000 m3

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Overview – Existing Consents

Discharge treated wastewater to Waimea Inlet Consent Limits – Treatment Quality:

  • Indicator bacteria - Human health
  • Oxygen depleting potential (BOD5) - Ecology
  • Total suspended solids - Ecology and visual
  • Nutrients (nitrogen and phosphorus) - Nuisance

growths

  • Metals and other compounds - Ecology
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Overview – Existing Consents

Discharge treated wastewater to land (irrigation)

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Overview – Existing Consents

Discharge treated wastewater to land (irrigation)

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Overview – Existing Consents

Discharge treated wastewater to land (irrigation)

  • Up to 1,040 m3/day may be irrigated (centre pivot)
  • Irrigation area ~20.5 ha
  • Provides NRSBU with flexibility to manage

wastewater – alternative to discharge to Waimea Inlet

  • No nitrogen fertilisers may be applied – minimises

nutrient discharges to groundwater and the Inlet

  • Soil and groundwater quality monitoring required
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Overview – Existing Consents

Discharge contaminants to air (odour)

  • Wastewater treatment can create odours
  • Consent prohibits offensive/objectionable odour

beyond WWTP boundary (‘odour boundary’)

  • Best Island residents most likely to be affected

(~650 m from WWTP)

  • Annual meetings with Best Island residents
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Overview – Existing Consents

Discharge contaminants (odour) to air

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Regulatory Framework

Relevant statutory documents

  • Resource Management Act 1991 (RMA)
  • Tasman Resource Management Plan (TRMP)
  • Nelson Resource Management Plan (NRMP)
  • New Zealand Coastal Policy Statement (NZCPS)
  • Waimea Inlet Management Strategy
  • Te Tau Ihu Settlement Acts (x3)
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Regulatory Framework

Policy 23(2) – New Zealand Coastal Policy Statement

  • 2. In managing discharge of human sewage, do not

allow:

  • a. discharge of human sewage directly to water in

the coastal environment without treatment; and

  • b. the discharge of treated human sewage to

water in the coastal environment, unless:

  • i. there has been adequate consideration of

alternative methods, sites and routes for undertaking the discharge; and

  • ii. informed by an understanding of tangata

whenua values and the effects on them.

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Assessment of Environmental Effects (AEE)

AEE will be based on:

  • Review of existing monitoring data/results
  • Waimea Inlet (Cawthron)
  • Groundwater
  • Soils
  • Odour complaints
  • Consideration of alternatives – including land

application feasibility – required by RMA and NZCPS

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How well do we do this

  • Wastewater discharges comply with consent

conditions

  • Effective treatment of waterborne pathogens
  • Evidence supported by environmental outcomes

will be presented by Cawthron

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Bell Island performance compared to current consent limits

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Wastewater Influent – Key Parameter Trends

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Wastewater Influent - Daily Inflow

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Treated Wastewater - Daily Discharge m3

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New initiatives

  • The NRSBU long term capital budget = $26.6 million and is mainly aimed

at enhancing the environment.

Wind generated mixers used to replace electric equipment.

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Conclusion

The NRSBU aspire to

  • meet the needs and expectations of our

community

  • use natural capital were feasible to meet objectives
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Dr Rob Lieffering – Senior Environmental Consultant Client: Nelson Regional Sewerage Business Unit (NRSBU) Date 14 June 2017

Resource Consent Renewal Bell Island Wastewater Treatment Plant (Continued)

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Additional Studies

Further work currently being undertaken:

  • Public health risks need to be better

quantified/assessed

  • To determine the movement, dispersion, and

dilution of treated wastewater following discharge

  • Existing information outdated - 1995 NIWA dye study
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Current understanding of movement of treated wastewater (based on 1995 NIWA study)

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Additional Studies

Further work currently being undertaken:

  • Hydrodynamic model of Waimea Inlet and

Tasman Bay

  • Field work (Cawthron)
  • Model development (MetOcean)
  • Model will be used to determine treated

wastewater pathways and dilutions

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Extent of Hydrodynamic Model

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Hydrodynamic Model – Preliminary Output Video

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Additional Studies

Quantitative Microbial Risk Assessment (QMRA):

  • Uses hydrodynamic model output
  • Will assess risk of illness for water sports/recreation
  • Swimming
  • Water skiing
  • Kite boarding
  • Paddle boarding
  • Will assess risk of collecting/eating shellfish
  • Initial “Sensitive Sites” identified, but input from

stakeholders sought (Posters on wall)

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Recreational water uses

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Shellfish beds

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Next Steps

  • Complete additional studies
  • Continue consultation with stakeholders
  • Prepare consent application and AEE
  • Lodge renewal application no later than 7

November 2017

  • Application will be seeking 35 year duration
  • Expected to be publicly notified early 2018 –
  • pen for public submissions
  • Hearing expected mid-2018
  • Decision expected mid/late-2018