Maintaining the sewer infrastructure for a community requires difficult decisions every day. The goals set for a given year can change: whether to increase capacity, improve efficiency or to prevent future breakdowns. The choices from there can get even more daunting, as there are hundreds of different solutions available, and the effectiveness of any one can be dependent on your local environment, skill of the installer and quality of the product being used.
   
Add to this the unknown of what may fail in a given year and your ever-shrinking budgets to work with, and you have probably created a dilemma that has no perfect answer. The question, “Can I afford to use that?” becomes a part of your daily grind.

If you’re like most, this is the definition of managing a public utility. Make the most with what you have and do your best to allow the public to live in blissful ignorance of the complexity required to provide service. How do you stretch your dollar as far as it will go?  Sometimes the best answer requires a little outside-the-box thinking. Here are some of the things to consider:

Time — Depending on how you manage your assets, your workforce may be on the payroll or contracted on an as-needed basis. But regardless of how you pay for time, you are paying for time. Some projects require more man hours to complete than others, while some products require more time to install or apply than others. If you aren’t factoring time into your evaluation of proposed projects, you are missing out on some significant opportunities to stretch your dollar.

Durability — Some products may claim to last forever, but every product has a design life expectancy. Most will have warranties that can indicate the confidence of the manufacturer in the life expectancy of that product. But durability includes more than just product life. Durability is only really relevant as it applies to a system. That is, if the system fails, it doesn’t always matter that the product didn’t fail. When looking at durability, be sure to look at if or how a product impacts the durability of the system. Also, look at how sensitive the performance of the product is based on installation and the relative costs of failure for the part and the system. By making your project last longer, you can stretch dollars into the future.

Performance — Will the products you select have the result you are expecting? Not all products perform the same, so understanding product performance is an important part of the evaluation. You need to look for specific data about performance. That data should be generated from someone other than the manufacturer — either from a certified third party testing facility or from other communities that have evaluated the product. It can be challenging to get real data for how well a product performs its intended function, but this is time well spent (since poor performance can lead to more expense rather than less).

Incidental Costs — Have you ever noticed that some products are just harder to use than others? Some require special equipment to handle, while some require special care not to damage them before they are installed. And then there are products that just don’t seem like they were designed with a human being in mind when it comes to application. Don’t dismiss these difficulties, as they will creep back into your bottom line. They could show up as delays in project completion, as extra capital expense or as significant workers’ compensation claims. Not to mention, they can turn a budget upside-down in an instant. Look for data from trusted sources, talk to people who have worked with different products and get feedback from the crews that you will use to do the work.  The people who handle a product can tell you a lot when it comes to incidental costs of working with it.

Do the Math — You will have to use something to turn all the information you have gathered into a decision. There are a variety of tools developed to help with this and depending on how much data and information you have, you may want to develop something unique for your situation. In general, however, the goal is to standardize the cost of product, labor and future repairs or replacements, as well as any savings that you expect to achieve — then weigh all this against your budget.

Case Study


After identifying the considerations of selecting a manhole product, putting this knowledge to use is the next step. Here’s an example of how a sewer district weighed its options and selected a product within its budget:
The sewer district had previously evaluated the systems that they currently use for treating the base capacity and had identified a cost of $20 per gallon of capacity. The capacity for the peak flows associated with inflow and infiltration (I&I) was identified to cost $7 per gallon. The reduction of three gallons of I&I would cover the expense of 1 gallon of base capacity.

An investigation for available remedies for I&I had led them to a number of studies and reports, including a report from the Water Environment Research Foundation that found, “attention to manholes as inflow sources in conditions where ground conditions reduce the impact of groundwater may achieve significant results.”  This was the basis for evaluating the grade rings, among many other products, as they planned for a remediation project.

A budget was set for the year, and through flow monitoring and inspection, a scope of work was being developed. Some of the manholes were structurally sound and would be sealed without reconstruction, while others were degraded enough that portions of them would be replaced. When all or parts of a manhole are being replaced, traditional construction specifications called for concrete grade rings to be used to make the final adjustments that brought the manhole frame up to level.

Before making a decision, the district wanted to compare using concrete rings to a new product such as Pro-Ring, from Cretex Specialty Products. It researched the product, evaluating its attributes and overall cost. The district found that the Pro-Ring technology was lightweight due to the expanded polypropylene (EPP) material it’s made from, as well as had the ability to adjust within 1/4 in. of desired height. A longer life expectancy, ability to absorb impact from traffic and durability rounded out its initial findings (The EPP rings don’t crack due to stress in the manhole system, and don’t corrode due to acids, chlorine or road
salts).

Next, it was important to identify the cost. Based on its initial cost, lifespan and price of additional materials for each system, Pro-Ring would be $280 per manhole — $200 less than estimated lifetime costs of available concrete technology.

The sewer district had a lot of information to review.  The analysis had required them to look at not only the cost of materials, but at the entire cost of operation for a given year. With the time savings and overhead savings added up, it appeared that the cost of the project would be close to equal for each type of construction. In the long term, it appeared that the EPP construction would cost less, since they would be able to go longer without going back for repairs.

Eric Dickson is general manager of Cretex Specialty Products.

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