This homework assignment is about reviewing a case study, identifying process$/$mechanical issues, and evaluating alternative technologies for selection of equipment, and making recommendations for upgrading an aging water reclamation facility $($WRF$)$ treating municipal wastewater.

Case:

You have been hired by an international consulting engineering firm as a Design Engineer and in your

first assignment you are required to conduct an evaluation of alternative technologies for the preliminary treatment works. You will submit your evaluation and recommendation in a Technical Memorandum.

After you have visited the site and gathered information about the plant, you have prepared a presentation for your client and discussed major challenges and potential solutions in a meeting. In this presentation, you pointed out the three most important process$/$mechanical issues at the preliminary treatment units.

Your presentation is well received, and you are now required to work on your assignment.

Essential parts of your presentation slides are included below for your evaluation.

Challenge:

As the Design Engineer, you are now required to evaluate alternative technologies using a multi criteria

evaluation matrix to select the recommended most technically feasible alternative for the aging grit

removal system at the plant. You are also expected to identify the three most important

process$/$mechanical issues at the preliminary treatment units. Alternative grit removal technologies for

your evaluation are listed below $.$

You are not required to develop capital, O&M and life cycle costs of alternative materials for digester gas

piping at this stage. The Contractor will develop cost estimates after your recommendation is accepted.

Alternative grit removal technologies

$$ Alternative A $=$ Detritus tank

$$ Alternative B $=$ Aerated grit chamber

$$ Alternative C $=$ Vortex grit removal

Multi Criteria Evaluation

Use a multi$-$criteria evaluation matrix to select the recommended alternative. The criteria used in the

evaluation are itemized below. Assign each criterion a weighting factor of $1$ or $2$ to reflect its relative

importance. A weighting factor of $1$ reflects the most important criteria and a factor of $2$ reflects the less

important criteria.

$$ Safety $-$ the mitigation of safety hazards associated with the operation and

maintenance of the new gas piping components within a system.

$$ Weighting Factor $=$ X

$$ Operability $-$ the plant$$s staff overall experience with operation of the new gas piping

material.

$$ Weighting Factor $=$ X

$$ Maintainability $-$ the labor intensity and frequency associated with routine

maintenance of the new gas piping.

$$ Weighting Factor $=$ X

$$ Constructability $-$ the relative ease with which construction of new gas piping activity

can be implemented and not disrupt current treatment operations.

$$ Weighting Factor $=$ X

$$ Compatibility $$ the relative compatibility with other piping materials used in the

digesters.

$$ Weighting Factor $=$ X

Assign a weighting factor for each alternative and based on the technical merits and key factors you

assigned for the listed criteria select the preferred technical alternative material. Assign each alternative

a score of $1$ through $5.$ A score of $1$ indicates the most advantageous alternative and a score of $5$

indicates the least advantageous alternative. For example, an alternative assigned a score of $1$ under

safety criterion is considered the safest alternative material compared to the other alternatives. Multiply

the scores by the weighting factor for that criteria to obtain a weighted score for each alternative

material. Then total and compare the weighted scores for each alternative. Develop a matrix like the

examples presented in the class. Select the most desirable technical alternative with the lowest total

ranked score.

Write a paragraph of discussion under each criterion and prepare a Technical Memorandum presenting

your approach to evaluation justifying your recommendation for upgrading the grit removal facility at

the plant.