Appropriate Design Criteria Packages for Membrane Facility Procurement by the Design-Build Operate Process

摘要

Design-Build (DB) and Design-Build-Operate (DBO) procurement for publicly-owned potable water treatment facilities is rapidly growing as a desired mechanism for utilities to obtain new facilities often at reduced costs and avoidance of certain risks. In the procurement of such facilities using a DB or DBO approach, it is necessary for the owner and their consulting engineer to prepare a design criteria package. In keeping with DB/DBO procedures and a desire to maximize cost savings by minimizing constraints on process, design, and construction concepts, it is often desired to keep the design and operation criteria flexible. However, owners are also typically leery of relinquishing too much control over desired process selection, design approach including architecture, and equipment selection. A balance must be struck in the design package offered for competitive proposals that provides a level playing field and offers maximum flexibility for creative approaches while ensuring certain acceptable levels of workmanship and functionality for supplied equipment. The DBO packages must also provide a desirable balance between capital and operational expenditures by requiring a certain quality of equipment so that future excessive maintenance costs are not more than the stated capital cost savings. To date few membrane treatment facilities have been procured using a DB or DBO approach. Due to permeate water quality and operational criteria differences between membrane manufacturers and their specific membrane models, care must be taken to accommodate all potential membrane suppliers. This need is further emphasized by the fact that there are relatively few suppliers of membranes to the municipal market and the loss of one potential bidder could