For a small community, Greenfield, Mo., was plagued with what appeared to be major inflow and infiltration (I&I) problems. The sewer pipes...
Membrane system implementation is similar to any other water treatment project in terms of phases; however, it is unique in terms of the degree of details and procurement steps.
A typical project implementation will have the following phases:
Phase 1: Feasibility Study
Phase 2: Conceptual Design
Phase 3: Detailed Design
Phase 4: Bidding Period
Phase 5: Construction
Phase 6: Functional Testing and Commissioning
Phase 7: Startup Phase
Phase 8: Project Closeout
Phase 1. During this phase, the project water quality goals and plant capacity are set. Then, with assistance from membrane manufacturers and specialty consultants, a critique of various technologies is conducted to assess feasibility and cost-effectiveness of membrane options. Many utilities can complete this phase with their own staff. It is crucial to give a “yes” or “no” to membranes in this phase.
Remember, membranes may not be the best option for all types of waters and in every application.
Phase 2. In this phase, advice from a specialized consultant is a must. This is when layouts and conceptual design are done to evaluate membrane options. This is also the last practical and cost-effective phase where you can go back to the feasibility study if the membrane is not found to be the best alternative.
Detailed water quality investigation and sometimes piloting is done in this phase to verify membrane applicability and type of systems to use, as well as setting design parameters for the next phase. Depending on the piloting requirements and periods, this phase could take as little as two or three months to more than a year; if seasonal, water quality changes are substantial.
If a pilot study is required, a detailed test protocol should be prepared to not only evaluate various manufacturers but also as a basis for operations and maintenance (O&M) cost evaluation. It is highly recommended to prepare this test protocol with guidance from the permitting agencies and make them a part of the decision process.
The conclusion of Phase 2 should determine what type of membrane to use and the membrane manufacturer. If manufacturers were invited to pilot test, you must ensure that they are being evaluated in a fair and open environment. Test protocol is the key evaluation tool. It is also recommended to get them involved early in the draft test protocol so there are no surprises.
Phase 3. Before starting Phase 3, all design parameters, plant capacity, reliability and redundancy factors, stand-by provisions, temperature and water quality considerations must be established. They will then become the design basis for the specialty consultant. Phase 3 is essentially when the local engineers working with the specialty consultants to perform detail designs and preparing the bidding documents while the local engineer is focusing on the site work, building, incoming power, etc. The specialty consultant is doing detail design and layout for the process equipment and setting the bidding requirements for the membrane system.
Depending on the project schedule and local requirements, typically three major submittals are prepared: 20% to 30%, 60% to 70% and 100% design.
It is critical to establish the type of procurement and short list manufacturers, and identify all key process needs during the 20% to 30% phase. Even with the same membrane technology, the system layout, process needs and power/chemical requirements are very different.
Phase 4. This phase is the most complex phase in membrane system implementation. There are many different methods and ways of bidding membrane systems, each with its own advantages/disadvantages.
Phase 5. The success and smoothness of Phase 5 depends on phases 3 and 4. The single most important factor becomes how detailed the bid document is and who is responsible for what material and equipment, as well as testing and guarantees.
Phases 6 and 7. Typically, each entity performs its own function in phases 6 and 7, except the overall controls, for which one entity should be taking charge.
Phase 8. This phase is preparing as- builts, final O&M manuals and each entity completing its punch lists. The specialty consultant can be of great assistance to compile all O&M and shop drawings and provide a comprehensive operator training on the overall plant process, while each supplier provides training of individual components.