Rotorua Wastewater Treatment Plant Applications for Resource Consents and Assessment of Environmental Effects
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ROTORUA WASTEWATER TREATMENT PLANT APPLICATIONS FOR RESOURCE CONSENTS AND ASSESSMENT OF ENVIRONMENTAL EFFECTS APPLICATION EDITION Prepared for the Rotorua Lakes Council 20 August 2018 Rotorua Wastewater Treatment Plant Application for Resource Consents and Assessment of Environmental Effects Rotorua Wastewater Treatment Plant Discharges Application for Resource Consents and Assessment Environmental Effects Authors Overall Approach, Technical, Alternatives, Consultation, Jim Bradley Stantec New Zealand Project Background Dr Rob Lieffering Stantec New Zealand Structure, Conditions, Statutory Assessment Adam Jellie Stantec New Zealand Planning, Consultation Sections Dr Doug Boddy Stantec New Zealand Air Discharges Kirsten Norquay Stantec New Zealand Public Health Risk Assessment Graham McBride NIWA Quantitative Microbial Risk Assessment Existing Scheme Wastewater Treatment Plant, Alison Lowe Rotorua Lakes Council Monitoring and Water Environment Effects Assessment Johnathon Bannatyne APR Consultants Project Context, Growth, Economics, Tourism Dr David Hamilton University of Waikato Water Environment Effects Assessment Dr Jonathan Abell Ecofish Research Water Environment Effects Assessment Dr Christopher Dada University of Waikato Water Environment Effects Assessment Chris McBride University of Waikato Water Environment Effects Assessment Antoine Coffin Te Onewa Consultants Tangata Whenua Consultation Willie Shaw Wildlands Consultants Ecological Assessment Richard Hart Wildlands Consultants Natural Character, Landscape and Amenity Richard Hunt Jacana Consulting Te Arikiroa Thermal Channel Construction Methodology Reviewers Greg Manzano Rotorua Lakes Council Overall Project Dr Rob Lieffering Stantec New Zealand Overall Project Theresa Le Bas Tompkins Wake Overall Project Dr David Hamilton University of Waikato Water Environment Assessment Dr Paul Heveldt Stantec New Zealand Air Discharges Peter Loughran Stantec New Zealand Public Health Risk Assessment Jim Bradley Stantec New Zealand Overall Project This Assessment of Environmental Effects (AEE) Document is supported by eleven Support Documents and two Companion Documents. Information included in this AEE has been sourced by many of those documents. Accordingly, the authors of the Support Documents have also contributed to this AEE. A full list of the Support Documents is included in the Contents Pages of this document. Technical information relating to the Proposed Treatment Plant process and the treatment and land application options has been sourced from consultants Mott MacDonald’s Design Statement (included as Appendix H to the AEE and Support Documents as set out in Section 9 of this AEE). Status: Application Edition 20th August 2018 Project No.: 80509283 Our ref: Rotorua WWTP AEE 2018-08-20 Rotorua Wastewater Treatment Plant Application for Resource Consents and Assessment of Environmental Effects Executive Summary The Rotorua District Council, operating as the Rotorua Lakes Council (RLC), operates the Rotorua Wastewater Treatment Plant (WWTP) and treated wastewater is currently irrigated to land at a Land Treatment System (LTS) located within the Whakarewarewa Forest. The irrigation is scheduled to cease and the RLC needs to find a viable alternative location to discharge the treated wastewater from the WWTP. The RLC has undertaken a lengthy process to find a viable alternative and this process has resulted in a Preferred Scheme being selected involving a significant upgrade to the WWTP, resulting in a highly treated wastewater, and that treated wastewater being discharged to an unnamed tributary of Lake Rotorua. The unnamed tributary is referred to as Te Arikiroa Thermal Channel. Various resource consents are required to implement the Preferred Scheme and for the discharge of treated wastewater and contaminants to air from the WWTP over the next 35 years (being the duration of consent being sought for the discharges from the WWTP). This document is the combined Assessment of Environmental Effects (AEE) filed in support of two applications for resource consents by the RLC associated with the Preferred Scheme. One application is for various resource consents from the Bay of Plenty Regional Council (BOPRC) and the other is an application for various resource consents from the RLC (as consent authority). This AEE has been prepared in accordance with the requirements of section 88 and Schedule 4 of the Resource Management Act 1991 (RMA). The process which has resulted in selecting the Preferred Scheme has involved a large number of stakeholders and various committees, sub-committees, and advisory groups were also established. A Rotorua Project Steering Committee (RPSC) was formed and established specific project goals. These goals were critical in setting the terms of reference for the project development and decision making in identifying and selecting the Preferred Scheme to replace the existing LTS. These goals included working with the community, key stakeholders, and tāngata whenua to ensure a Best Practicable Option (BPO) wastewater treatment and disposal / discharge solution was selected. A comprehensive assessment of alternatives in respect of wastewater treatment options, discharge methods, and discharge locations, has been undertaken as part of selecting the Preferred Scheme. A Technical Advisory Group (TAG) was established to consider the technical aspects of the wide range of options available and to evaluate the options not only from a technical and cost perspective, but also from the actual and potential effects of the treated wastewater discharge on the receiving environment. The RLC has progressed the development of the Preferred Scheme to the point that a concept design has been developed for a proposed upgrade to the WWTP so that treated wastewater can be appropriately discharged to Te Arikiroa Thermal Channel, which in turn discharges to Puarenga Bay (also known as Sulphur Bay), which is part of Lake Rotorua. As part of the WWTP upgrade design, the treated wastewater is proposed to pass through a new land contact bed before being discharged to Te Arikiroa Thermal Channel via a new discharge structure – this component of the design has been included to specifically address Māori cultural concerns associated with direct discharges of human waste to water. The proposed upgrade to the WWTP will result in a very high quality wastewater which will be able to be beneficially reused by other persons (e.g. for irrigation and/or industrial process water) and the public health risks associated with contact recreation (swimming and boating) within the receiving waters will be acceptable – a ‘double barrier’ treatment system is proposed involving the use of membrane filtration followed by ultra-violet (UV) light disinfection which will remove pathogens and particulate matter to exceptionally low concentrations. Beneficial reuse will reduce the volume of treated wastewater needing to be discharged to Lake Rotorua via Te Arikiroa Thermal Channel. Status: Application Edition 20th August 2018 Project number: 80509283 Page i Our ref: Rotorua WWTP AEE 2018-08-20 Rotorua Wastewater Treatment Plant Application for Resource Consents and Assessment of Environmental Effects The Preferred Scheme will not increase nutrient inputs into Lake Rotorua above those provided for in the BOPRC’s ‘allocations’. An annual mass load limit for total nitrogen (TN) and total phosphorus (TP) allowed to be discharged is proposed, with the TN limit allowed to be increased as rural land is developed and connected to the WWTP – a transfer of TN allocation from the rural land use to the WWTP is proposed which aligns with the Memorandum of Understanding (MoU) entered into between the BOPRC, the RLC, and Te Arawa Lakes Trust. The RLC has undertaken a wide range of environmental and technical investigations to inform this AEE. Studies have investigated the water quality, ecology, and mixing of the treated wastewater discharge to Te Arikiroa Thermal Channel and Puarenga Bay (Lake Rotorua). No significant adverse water quality effects are expected within Puarenga Bay outside of the zone of reasonable mixing as a result of the discharge of treated wastewater from the WWTP. In addition, no significant adverse odour effects are predicted to occur beyond the designation boundary of the WWTP. Removal of indigenous geothermal vegetation, modifications of Te Arikiroa Thermal Channel and construction of five small bunds adjacent to the Puarenga Stream are expected to have some unavoidable adverse ecological, natural character, landscape and amenity effects – a minimal intervention approach is proposed to minimise these adverse effects to the greatest extent practicable. Extensive consultation has been undertaken with tāngata whenua, statutory bodies, key stakeholders, and the wider community to inform this AEE. The consultation activities were undertaken between 2014 and July 2018. Consultation with tāngata whenua has been ongoing and two Cultural Impact Assessments (CIAs) have been prepared, both of which confirm that the Preferred Scheme exhibits a number of positive and significant adverse cultural effects. The Preferred Scheme is innovative and meaningful because it addresses important cultural concerns. Further, it incorporates Māori concepts and values at the forefront in the conceptualisation and design of the proposed land contact bed and discharge structure. A range of measures are proposed to avoid or mitigate the identified actual and potential adverse effects – these being included in a comprehensive