A framework for the implementation and design of pilot-scale distribution systems

In recent years, model distribution systems have become valuable tools for understanding physical, chemical and microbiological processes that occur in full-scale distribution systems. These systems enable numerous treatment strategies to be examined in controlled conditions and without adversely affecting the water quality at a customer9s tap. Many model reactors have been developed for obtaining water quality data for evaluating very specific processes that occur in the distribution system (e.g. trihalomethane formation). The simulated distribution system (SDS) test is used to predict the formation of trihalomethanes in the distribution system, annular reactors (AR) are commonly used for biofilm studies and pipe rig systems can be used for a variety of studies including corrosion and biofilm. Of the three model reactors, pipe rig systems provide the most flexibility, however relatively few standard or de facto testing procedures have been developed in comparison to the other laboratory-based model systems (e.g. SDS test protocol). There are several hydraulic configurations that can be modelled along with various lengths and diameters of different pipe materials. However, this flexibility and the lack of standard pipe rig designs cause difficulties in making broad comparisons among research projects. This paper outlines the important design variables of a pipe rig system and provides examples of different options for each variable. Based on a thorough review of previous pipe rig studies, a framework was developed to assist in the design and selection of pipe rig configurations. It is recommended that the framework provides a method for selecting the physical and hydraulic configuration for future pipe rig investigations. Ultimately, the framework would provide the water industry with potential designs that would allow for improvement in data evaluation and strategies for minimizing water quality degradation in distribution systems.