An evaluation of the ability of centrally managed decentralised wastewater treatment systems to offer greater opportunities for wastewater management within New Zealand

Abstract

The collection and disposal of wastewater is an essential practise in any modern settlement for controlling the transmission of waterborne diseases and for preventing degradation of the surrounding environment. During the past decade the development of new technologies has seen a substantial growth in the number of effective decentralised wastewater treatment systems being implemented throughout the world and in particular the USA, UK and Australia. Within New Zealand however, the development of modem decentralised wastewater treatment systems has been greatly restricted by the lack of enabling legislation and inaccurate public sentiments.

This paper describes the use of modern decentralised wastewater treatment systems and their potential application within New Zealand. In attempting to illustrate the points raised within the main body of text, a case study of wastewater options within the Rodney District has been undertaken, in which a series of different wastewater options are evaluated. Observations arising from the case study validate the notion that provided adequate management structures are implemented, decentralised wastewater treatment systems are at times the most effective means for providing wastewater services within New Zealand.

In recognition of this fact, this paper also examines the various levels of management required for the effective implementation of decentralised wastewater treatment systems and contrasts these with the current management structures in place within New Zealand. Furthermore, this paper also defines what a decentralised wastewater system is, and examines many of the barriers restricting the widespread implementation of decentralised systems within New Zealand.

Based on overseas observations and preliminary investigations undertaken within New Zealand, decentralised wastewater treatment systems merit serious consideration in any evaluation of wastewater management options for small and mid-sized communities and new developments, particularly those on the urban fringe.

As wastewater issues become more prominent within New Zealand, it will be necessary for a far greater level of attention to be placed on decentralised systems, something historically they have not received within New Zealand.