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Are nightmares about reporting deadlines, stormwater exceedances and six-figure treatment systems keeping you up at night? Hopefully, my true tale of Mapistry’s customer successes will ease your worried mind and lull you back to sleep. These three California facilities were able to return to baseline status without the fancy and expensive treatment systems everyone dreads. Once upon a time… there were three industrial facilities: a motor vehicle manufacturer, an electronics recycler, and a chemical fabricator. All of these facilities were struggling to meet the thresholds for their stormwater samples and had exceeded for a variety of parameters. Each location had different industrial activities and potential pollutants occurring on site, but with a few cost-effective suggestions from Mapistry, they were all able to lift the curse on their stormwater samples and live happily ever after!

The Motor Vehicle Manufacturer

Struggling with exceedances in aluminum and iron, the most commonly occurring metals in the earth’s crust, our motor vehicle manufacturer was unsure if their exceedances were sourcing from their activities or non-industrial dirt being aerially deposited onto their site like Tinkerbell’s pixie dust. After some professional sleuthing, the following sources were discovered. A potential pollutant source on-site was open roll-off bins which contained aluminum scrap, but no iron.

Issue #1: Open Bins

Though the bins did not contain iron scrap, many of them were in bad shape with rusted bottoms and holes all over. Due to around-the-clock manufacturing, operational constraints kept the roll-off bins from being covered, exposing them to rain. The issue with uncovered bins is that they can fill with rainwater, which the metals leach into, and the rainwater slowly seeps through the many holes in the rusted bottoms of the roll-off bins out into the storm drains.

Solution #1: Bin Coverage

The simple solution for this was to get covers for the bins. Though this sounds simple it can be a bit of a hassle to get the company you are renting the bin from to supply bins with covers. If the bins are owned by the facility, then a company like Impact Plastics or Consolidated Fabricators can provide prefabricated lids for all size bins. In this case, the facility’s management simply made it clear that they were not going to accept bins that were in bad shape (i.e. rusting with a bunch of holes) or without covers. For the handful of bins that could not be completely closed due to larger scrap metal pieces, tarps were thrown over the bins during rain events, and the bin pick-up frequency was increased.

Issue #2: Metal Fines

Dealing with metal cutting and sanding, though those activities occurred indoors, metal particles managed to get tracked out into the yard either through employees shoes, forklift tires or while transporting metal scraps to the larger roll-off bins. These metal fines were also likely sourcing from the residual stormwater leaking out of the holes in the bins when the scrap bins were picked up for being hauled off-site.

Solution #2: Increased Sweeping

Sweeping at the facility was already occurring with a mechanical sweeper, but the frequency was increased to daily and even multiple times a day dependent upon activities and potential exposures. (Don’t worry, Cinderella received a raise for her added workload.) Simple compliance housekeeping, such as sweeping, should always be the first line of defense because filters or treatment systems will perform poorly or get clogged quickly when overloaded with pollutants. Though they were able to do it in-house, contracting or purchasing a regenerative air sweeper can be cheaper than buying a treatment system and could be the magic spell your facility needs to return to baseline.

Issue #3: Incorrect Sampling Methods

Many facilities encounter difficulties when dealing with sampling, that is likely why this facility had contracted a third party to conduct theirs. There were hydrodynamic separators already installed at their site to aid in the reduction of suspended solids. The only issue was that the third party was sampling the influent stormwater going into the separators instead of the effluent stormwater, thus not getting any of the filtered stormwater.

Solution #3: Sample Location Correction and Cleaning of System

Sampling correctly can be tricky. However, it is incredibly important to ensure that your stormwater samples are not high in pollutants. Making certain to sample after any filters, or treatment is essential for clean samples. I know you’re thinking, “well duh Amber, that’s why we installed filters/treatment,” but sampling upstream from best management practices happens all the time. To solve this, we shifted the sampling point downstream of the hydrodynamic separator and had the facility clean out their storm drain system and separator. Accumulation of sediments and metal particles can muck up separation systems, so annual cleanings/replacement of filters is generally a good rule of thumb.

The Electronics Recycler

Our next true tale is of an electronics recycler that was exceeding aluminum, iron and chemical oxygen demand (COD). Similar to our previous story with the manufacturer, non-industrial aerial deposition sources were suspected to be contributing to the high metal levels.

Issue #1: Aerial Deposition on the Roof

This particular site is located in an agricultural area with high winds, but also vents activities to the roof. Though the vented activities are filtered through baghouses, the one on the roof had failed before, and unless maintained regularly, baghouses are as reliable as the straw one in Three Little Pigs. Samples of roof runoff were collected at downspouts and demonstrated high levels of metals, but since it was impossible to separate non-industrial deposition from vented industrial activities, it was difficult to prove that it was coming from the surrounding community.

Solution #1: Roof Cleaning

The roof was pressure washed, and all wash waters were captured and disposed of as waste. This took weeks, but the results were spectacular! A dark grey roof was once again white, and the baghouse on the roof is now inspected monthly to prevent particulates from being exposed to stormwater.

Issue #2: Material Storage

Like many industrial facilities, our electronics recycler had a boneyard. We find that it can be complicated to dispose of old equipment or determine what is reusable, but ye be warned: boneyards can stain your stormwater samples darker than a witch’s brew. This facility’s metal equipment and wooden pallets were doing just that.

Solution #2: Disposal and Storage Location of Materials

The first thing to do in a situation like this is to ask yourself what do we REALLY need? What will actually be reused? Do not hold on to things that you will not reuse: sell them, scrap them or donate them. Any material that you do keep should be stored in a single location as far away from a storm drain or discharge point as possible. Raise everything off the ground by placing them on pallets or in bins, and cover everything with tarps before storms.

Issue #3: Sampling Prior to Natural Filtration

All stormwater at this facility discharges to one location, making it much easier for collection, but limiting the ability to determine problem areas from high sampling results. For this facility, samples were being collected at the pipe where stormwater was pumped to the surface from the underground system, but prior to the actual storm drain where the stormwater was discharging. This did not allow for the natural vegetation in the swale between the pipe and the storm drain to filter the stormwater before discharging off-site.

Solution #3: Rock Check Dams

Samples should only be collected at locations where stormwater is actually discharging from the facility, so we moved the sampling location to the storm drain to allow the customer’s samples to reflect their swale’s natural filtration. Rock check dams were also installed in 5-foot intervals along the swale, further filtering the stormwater prior to discharge and sampling. Ta-da! Their sample results dropped below NALs.

check dam diagram

The Chemical Fabricator

Our final tale tells of a chemical fabricator who was having difficulties with nitrate + nitrite as nitrogen (N+N as N). This case was unique because there were no industrial activities occurring outside at the facility that could have been contributing to the N+N as N exceedances. It took a bit of sweat but we were able to come to the rescue.

Issue #1: Sandblast Media

Baghouse issues reared their ugly head again at out chemical fabricator’s facility. Indeed, our fabricator had a baghouse installed for a sandblaster that removed paint on cylinders that were being recommissioned. The baghouse was slowly leaking some of the sandblast dust, and coatings generally contain nitrates.

Solution #1: Fix Baghouse and Vacuum Daily

Inspecting your baghouses often is critical to ensure that there are no leaks and that filters are functioning properly. A leak or failure should be addressed promptly with cleaning and proper media disposal. Our gallant chemical fabricator fixed the baghouse and started vacuuming fugitive particles at the end of each workday.

Issue #2: Bioswale Fertilization

To tell it twice, it’s a good idea to allow for natural vegetation to filter your stormwater prior to discharge. Our chemical fabricator is lucky enough to have a beautiful bioswale to do just this, but in tending to the vegetation, fertilizers were sprayed during the summer. Fertilizers are high in nitrogen because it is great for plants, but it can lead to algal blooms which suck all the oxygen out of the water, killing Nemo and his cousins.

Solution #2: Eliminate the Use of Fertilizers

The solution here was my daughter’s favorite Frozen song: “Let It Go”. Simply don’t use fertilizers if your SIC code requires N+N as N sample data. Though your bioswale may not become a forest worthy of Bambi’s backdrop, it will continue to help with filtration as opposed to causing the very curse you’re trying to reverse.

Happily Ever After

A common thread stitching together these true tales is that getting the little things right, such as proper housekeeping, site knowledge, and sampling techniques makes a world of difference, even in addressing exceedances across different parameters. Most of these suggested remedies are relatively universal for industrial facilities and could potentially help your facility get out, or stay out, of level 1 & 2 (and a villainous role in the local paper). So before you fork out half a million dollars on a fancy treatment system, rub our genie lamp and discuss it with us!

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