Risk assessment, costs and benefits for community effluent reuse and disposal schemes: contrasting experiences from Victoria and New Zealand

Specific challenges to the provision of a sustainable wastewater service for existing towns with poorly performing on-site systems are being identified through both domestic wastewater management planning and the Victorian Government Country Town Water Supply and Sewerage Program. A key challenge is the development of economically and socially viable effluent reuse and disposal schemes for community wastewater systems that also meet regulatory requirements for the protection of human health and ecosystems.This paper presents the outcomes of a risk assessment and cost benefit analysis for a proposed community wastewater system for a small town in central Gippsland, Victoria. Preliminary modelling suggests that very limited improvement in environmental/human health performance can be expected with the provision of large storage facilities (i.e. wet weather dam) and restriction of deep drainage. Recent experiences from New Zealand support the outcomes of this assessment. Current Victorian guidelines, however, discourage deep drainage in effluent irrigation and therefore the benefits that such schemes can deliver in the future. The outcomes illustrate the need for case by case risk analysis and triple bottom line assessment of wastewater servicing options.