Sustainable remediation in New Zealand

Transcription

1 Sustainable remediation in New Zealand Joanne Ferry and Peter Cochrane Tonkin & Taylor Ltd

2 Introduction What is sustainable remediation? The practice of demonstrating, in terms of environmental, economic and social indicators, that the benefit of undertaking remediation is greater than its impact and that the optimum remediation solution is selected through the use of a balanced decision making process. Sustainable Remediation Forum UK

3 NZ contaminated land framework Resource Management Act (RMA) Implementation of the RMA by regional and local councils Ministry for the Environment (MfE) Central government guidance on contaminated land Technical guidance on contaminated land

4 RMA (1991) Section 5 Promote sustainable management of natural and physical resources Enabling people and communities to provide for their social, economic and cultural wellbeing and for their health and safety Safeguarding the life-supporting capacity of air, water, soil, and ecosystems Avoiding, remedying, or mitigating any adverse effects of activities on the environment

5 RMA (1991) Regional council responsibilities Discharges to the environment Effects on air, soil and water Loss of soil through landfill and cleanfill disposal? District/City council responsibilities Effects of land use Effects on human health Fit with planning and strategies for the community Life span of remedial project?

6 MfE Ministry for the Environment vision: A prosperous New Zealand where a healthy environment enhances social and economic wellbeing Guidelines for the management of contaminated land Enhance environmental awareness of the issues at contaminated sites and promote outcomes in accordance with the principles of the RMA

7 Technical guidance MfE hierarchy of guidelines NZ risk based International risk based NZ threshold based International threshold based Allows for selection of most relevant guidelines to a site Allows for site specific risk assessment

8 Technical guidance Oil industry guidelines (MfE 1999) Establishes technical, risk based guidelines for hydrocarbon contaminants in soil Includes information about how to manage hydrocarbon contamination Natural attenuation cost effective, long time period Containment may restrict future land use, ongoing liability issues Land farming large land requirements, potential odour issues Landfill disposal potentially expensive, no ongoing liability

9 Sustainability is built into many aspects of the contaminated land management framework in New Zealand So is remediation in New Zealand happening sustainably?

10 Case study Former petrol station site proposed for childcare facility Extent of contamination Localised hydrocarbon contamination BAP eq. above produce consumption guideline Occasional asbestos fibreboard in soil No groundwater issues

11 Case study Remedial strategy Excavation and landfill disposal of localised areas of hydrocarbon impacted soil Construction of raised garden beds and importation of clean soil to allow for vegetable growing Risk assessment to determine the suitability of the soil for growing fruit trees Hand picking of any ACM during redevelopment Preparation of Site Management Plan to address ongoing issues of ACM and asbestos fibres in the soil, and vegetable growing requirements.

12 Impacts on air Impacts on water NA Impacts on soil Impacts on ecology Intrusiveness/ aesthetics / / NA/ Resource use and waste / Environmental sustainability indicators Impacts of dust generation and asbestos fibres addressed during excavation through dampening of exposed soil. Other potential impacts such as generation of greenhouse gases and the release of gaseous pollutants were not considered. No groundwater or surface water was encountered at the site. Potential impacts of remedial activity on water considered to be minimal. Consideration of potential future uses of soil for gardening was taken into account. Contaminated soil was disposed of to landfill potential adverse effect as soil was lost (not remediated or able to be reused). Clean soil excavated during redevelopment was available for reuse however potentially lost if disposed of to a cleanfill facility. Site was located in urban area, ecological values considered to be low. Opportunities for enhancing biodiversity or other ecological values were not explored. Generation of noise and traffic during remedial activity were considered to be minor, minimal offsite disposal limited truck movements at the site. Redevelopment of the site considered an aesthetic improvement of previous abandoned buildings. Consideration of the wider environmental setting considered by TLA when it granted the land use consent Fuel consumption, use of clean soil and water not directly considered when developing remedial strategy but reduction of offsite disposal of soil, and reuse of clean excess soil all contributed to effective resource use during the project. Waste generation not specifically considered but was minimal due to the remedial strategy. No land was lost or wasted as remedial strategy addressed proposed activities in all areas of the site.

13 Direct costs and direct economic benefits Indirect costs and indirect benefits Gearing Employment/ human capital Life-span and project risks Flexibility / / Economic sustainability indicators Cheapest options were selected for each component of the project. Ongoing cost of managing the remedial strategy were considered at the time of development. Separation of contaminated soil from clean soil reduced landfill costs. Potential impact on property value as site is still considered to be contaminated. This was accepted by client as they propose to retain ownership of the site in the medium term. No consideration given to potential redevelopment of the site in the future due to clients plan to retain the site. Definite improvement to community through the redevelopment of a contaminated site and establishment of child care facility. Site redevelopment has provided employment opportunities for child care workers and facilities for the community. Risk from residual contamination considered to be outweighed by benefits of employment, community facility and education of children. Employment and human capital not considered during remedial project itself. Site Management Plan addresses activities and situations expected to occur during the use of the site as a childcare facility. Applicability for other site uses was not considered. Low risk remedial solutions were selected so there was little chance of variations being required during remediation. Potential for future change in land use not directly considered. Site is still contaminated so may require further work in future if redevelopment is proposed, or legislation around contaminated land changed.

14 Community involvement and satisfaction Human health / Ethical and equality considerations Impacts on neighbourhoods or regions Fit with planning and policy strategies and initiatives Uncertainty, evidence and verification /NA/ Social sustainability indicators Community consultation not undertaken directly for this project however remediation was a permitted activity under relevant Regional/District Plans therefore broader issues around contaminated land likely to have been considered during development of Regional/District Plans. Affects on long term human health considered in remedial strategy. Short term effects on workers taken into account. Short term effects on public health considered to be minor. Significant ethical issues associated with leaving contamination in place in light of use of the site by children. Potential impact on duty of care of facility operators. Impacts on neighbourhoods during remedial activity not directly considered however likely to be minor due to remedial strategy selected. Long term impacts on neighbour considered by others in terms of granting land use consent for the proposed development. Not directly considered during project but remedial activity was a permitted activity therefore broader issues around contaminated land likely to have been considered during development of Regional/District Plans. Professional judgement and MfE guidance used to balance technical uncertainty with cost of investigation and remediation. Evidence of adverse effects not considered but also not appropriate as measureable adverse effects would be unacceptable. No independent verification of remedial strategy undertaken, however strategy was accepted by Regional/ District Councils. Only limited verification of outcomes of remediation (validation sampling of hydrocarbon contamination).

15 Conclusion Sustainability is built into many aspects of the contaminated land management framework in New Zealand The implementation of these principles by local government has the potential to result in sustainable outcomes

16 The challenge To incorporate sustainability issues into the remedial decision making process To ensure that sustainable remediation occurs by design