Small Imperfections Matter

For complex surfaces or large areas of surfaces that require high levels of flatness or levelness, using a high definition laser scanner offers millions of coordinate data points for verification or detection of anomalies that cannot otherwise easily or quickly be acquired. From offices to high density storage facilities, synthetic surface playing fields, to high-speed race tracks, the ability to rapidly and accurately measure and model large surfaces can highlight the small imperfections that can make a big difference.

In West Whiteland Township, post-construction high definition surveying was utilized over 12,000 square feet of concrete floor to identify irregularities in placement that prohibited the installation of finishes, equipment and furnishings. Contour plans with color banding and spot elevations to demonstrate where problem areas were located, with 1/8-inch accuracy aided the client and contractors to swiftly repair and to rule out structural deficiencies. A similar analysis was performed for the roof to identify slope and stormwater drain placement.

FOR MORE INFORMATION: Patrick McCoy, PE, LEED AP, CSDP

It's the Little Things that Matter in Stormwater Management

With the Chesapeake Bay Reboot and new MS4 permit requirements hitting municipalities, many are left asking, “How can we possibly accomplish this?” There are many ways to attack a stormwater management issue, and in a large watershed, the task can seem daunting. But when you stop and think about it, it really comes down to identifying, prioritizing, and properly managing small areas of land within the larger watershed. The combined impact of small BMP projects on a watershed can be astounding, and are only amplified as one moves downstream.

At Spotts, Stevens and McCoy, we’re able to help our clients find the most cost efficient way of achieving their permit and pollution reduction goals. By utilizing mapping and modeling software, such as ArcMap, MapShed, and the BayFAST models, we’re able to get an idea as to how current land uses and activities within MS4 limits impact local waterways. We can also make adjustments for any existing BMPs, and plan for the future by determining the most cost efficient BMPs, and the location in which they’ll have the biggest impact on water quality. For instance, planting a rain garden down-gradient of a large parking lot could have a bigger impact on water quality than the same rain garden in a grassy park.

When we look at water quality issues at the local level, as opposed to a large watershed scale, not only are the concepts and goals more reasonable and achievable, but we’re able to engage the community to do their part. Instead of worrying about cleaning up the bay downstream, worry about cleaning up your local streams. These little actions can lead to big impacts. Residents will take pride in BMP projects and results, and will get excited about being able to use the waterways for recreation and fishing. As a bonus, you’ll still be doing your part in helping your downstream neighbors.

FOR MORE INFORMATION: Ashton Hogarth, Environmental Specialist

An example of how stormwater BMPs can be situated so as to achieve the greatest impact on water quality (images from the PA DEP Bureau of Watershed Management “Pennsylvania Stormwater Best Practices Manual”, Chapter 6)

Three Small Things that Can Make a BIG Difference in the Bottom Line

Inefficiencies in Municipal Wastewater Treatment Plants

Many Wastewater Treatment Plants (WWTP) were built at a time when budgets were not so tight and engineers erred on the side of caution to ensure that the plant met the design criteria. Many WWTP operators only have experience at one WWTP where they learned the trade from the previous operator. Those operators may have learned how to run the plant from the engineer who designed the facility and never changed their operations approach to adapt with the times.

What some call the municipal approach, “if a little is good, more must be better”, is often seen at smaller plants. This can lead to many unseen expenses. There are three areas that can provide big savings: energy usage, chemical addition, and sludge generation and disposal

The largest typical waste of energy in a WWTP is over aerating. The specific amount of air needed for a well running plant varies with the type of treatment process and the control capabilities. Activated sludge plants require a specific volume of air for BOD removal and nitrification. Online dissolved oxygen monitoring equipment can lead to a very efficient system if the associated controls are installed at the blowers. If these controls are not available, the operator has to select blower settings that allow for the plant to operate within the desired dissolved oxygen levels for the longest period of time possible. Dissolved oxygen will vary with changes of temperatures meaning that spring and fall are the most difficult seasons to maintain consistent dissolved oxygen levels.

Chemical addition is an area where waste often occurs. The ideal way to determine appropriate dosage is to perform jar tests. You add various dosages of chemicals to equal volumes of sample to determine which dosage provides the best flocculation and settlings to achieve desired treatment results. Overdosing of chemicals can lead to excess floc formation, sludge generation, and inhibit settling. If a facility doesn’t have the ability to perform jar tests, a chemical representative will typically give you a starting dosage and adjustments can be made by using visual analysis and laboratory data.

Sludge generation can be impacted by multiple operations approaches. Overdosing chemicals can lead to excess sludge generation and disposal requirements. Excess wasting can also generate increased levels of sludge. Each biological process requires sufficient biomass to treat the level of contaminants in the waste stream. Proper monitoring and control of the biomass will lead to optimum levels of sludge generation.

Multiple options are available to achieve cost effective disposal of the sludge generated from the treatment process. The majority of plants contract to have sludge hauled off-site. The volume of sludge to be hauled can be managed through various thickening processes selected by considering cost of the thickening equipment vs. actual hauling costs. Disposal options range from the least expensive, agricultural land application, to mine reclamation and landfill disposal, which is typically the most expensive disposal method. Some facilities have reed beds which have no annual disposal costs, but require a large capital outlay when they need to be cleaned out. A few facilities have incinerators which are labor intensive and come with high operating and maintenance costs.

The bottom line is that small changes in the treatment process can have a significant impact on the cost of operations. SSM can provide assistance to optimize operating costs for municipal facilities searching for budget dollars.

FOR MORE INFORMATION: Carl Kline, LO