Commissioning and Acceptance Testing - Design-Build for Water and Wastewater Projects - page 286

and downstream with connections for temporary water disposal may be needed for regu-
latory testing prior to approval.
While the tasks of treatment plant commissioning do not vary greatly between DB
and traditional DBB, the roles of the various parties are very different and impact how
commissioning is executed. A successful commissioning effort requires close coordina-
tion of the various parties and clearly defined objectives. Because of the single contractual
entity interface with the owner, close coordination is made easier with DB than with tra-
ditional DBB. As stated in DBIA's Manual of Practice (2008b), “The singularized respon-
sibility inherent in the design-build process is a powerful quality motivator.” These words
encapsulate the responsibility of the design-builder with regard to the commissioning and
acceptance testing of the facility.
In a traditional project, the engineer prepares the plans and specifications, answers
questions during construction, and advises the owner during the commissioning of the
treatment plant on the intended operation and treatment outcomes. In DB projects, the
engineer of the design-builder is responsible for many aspects of the commissioning. As a
result, during the design of the project, the engineer will include any components to allow
a fast and efficient commissioning process. The engineer is also involved in creating the
commissioning packages, which are manageable groupings of tasks that allow an efficient
flow of work. The engineer is also involved in developing the functional testing guidelines.
The contractor in a traditional DBB project is responsible for building the infrastruc-
ture as designed by the owner's engineer. The contractor's involvement in commissioning
of the facility typically starts before the end of construction, but it is usually not the pri-
mary focus until the major construction tasks are completed.
Also, in traditional DBB projects, the owner becomes the arbiter between the engi-
neer and contractor when problems or difficulties arise. The design by the engineer may
be fit for purpose, and the construction may be per the drawings and specifications, but
these do not always lead to a fully functional facility. Under the DB delivery model, the
responsibility to provide a fully functioning plant belongs to the design-builder, and the
owner has only one entity involved in providing that plant.
ACCEPTANCE TESTING
Once commissioning is complete, it is time to demonstrate that the WTP or WWTP func-
tions as required by criteria that are outlined in the contract. The process of establishing
contract compliance is called acceptance testing . Acceptance testing can cover a range of
activities, such as plant control functionality, plant reliability, treatment capability, and flow.
Acceptance testing can be conducted for the entire process (i.e., tests for plant capac-
ity and/or treated water quality) and for individual processes. Individual treatment pro-
cess testing is typically for package systems that have specific guarantees (e.g., headloss,
flow, water quality, etc.). Meeting the individual system guarantees is often necessary for
the plant to meet its overall process requirements. The reliability of packaged systems can
also be demonstrated by acceptance testing. The most common concept of acceptance
testing is to demonstrate that the plant's treated output meets performance guarantees
and permit requirements. This is where the primary focus often lies, but it is just one of
several parts of a successful acceptance test.