Robert Lenzini and his sister Wendy Gold are no strangers to the construction world, with 37 years of background in the excavating business, along with their parents and siblings. Gold and Lenzini are co-owners of MBL Recycling in Palatine, Ill. In addition to their thriving construction waste recycling business that sorts and processes metal, wood, cardboard, concrete, brick and plastic at their materials recovery facility, MBL also is the operator and manager for a shingle processing plant. And in 2007, MBL added concrete washout containers to their list of landfill-diverting options.
Gold shared her experience. She was having a driveway constructed at her house, and the man who delivered the concrete asked if she minded if they washed everything out in the grass.
“I told him that I did mind because there were children in the neighborhood. And to my knowledge that runoff material can cause second degree burns. It is very caustic,” Gold said.
Concrete washout containers are not new to construction sites. Lenzini was very used to seeing, as a standard construction site practice, the simple digging of a hole in the ground and lining it with plastic as a place to dump concrete washout runoff. Typically all the concrete trucks would wash out the chutes of their concrete mixers and hoppers of concrete pumps with a hose and sprayer nozzle every time they delivered concrete. All the extra concrete and debris was poured directly into the pit.
The remaining material in the pit will eventually dry up into concrete, but at the end of the job it’s a big messy pit that the contractor cannot leave on the job site, so workers must physically remove the pit.
Gold and Lenzini were one of the first firms in their area to do concrete washout containers. Lenzini got together with Poynette Iron Works, Poynette, Wis., a company that was involved in the manufacture of MBL’s other roll-off containers.
Gold explained, “Robert said, ’I’m going to call these guys because they’re good at everything.’ They are great engineers. We gave them our input; they gave us theirs and we designed a concrete washout container for ourselves.”
MBL put in their first order for a concrete washout container in the spring of 2007 and in June of that same year they received their first container. Since then they have ordered 50 and they will most likely have to order more. They also purchased a special truck for handling the servicing of the concrete washout containers.
Once the containers are placed and they are used for washout, they fill up with water from the hoses as well as from rain. When they are ready for a pump out, MBL sends their truck to remove the fluid and bring it back to their base of operations where it is filtered and reused. Their water truck is filled with the filtered water and sent out to be used as dust control.
When the washout containers are finished being used at a site, MBL will pump the fluid out and then load them back on a truck to be brought to a concrete recycling facility where they take all the concrete when it’s dried up. At that recycler they take the residual concrete waste material and crush it into aggregate.
A Growing Trend
“We weren’t exactly sure how all this would go over,” said Gold. “We were thinking that many of them would simply go back to their old ways of putting the liquid waste in the ground for a time at the construction site. But instead we found that there was a great deal of interest in the containers as there is actually a lot of interest in going green — and what better way could there be to help the environment than something as simple and effective as this?”
According to the EPA, the wash water from concrete residue is alkaline and contains high levels of chromium, which can leach into the ground and contaminate groundwater. It also can migrate to a storm drain, which can increase the pH of area waters and harm aquatic life. Solids that are improperly disposed of can clog storm drain pipes and cause flooding. Installing concrete washout facilities not only prevents pollution but also is a matter of good housekeeping at a construction site.
Besides digging and lining a pit, (which should never be connected to the storm drain system or drain to nearby waterways) there are other ways to take care of concrete washout. Sometimes straw bales or sandbags are stacked in a rectangle or square configuration and covered with at least two or three layers of 10 mil plastic. But according to the USEPA’s NPDES fact sheet, self-installed structures are much less reliable than prefabricated containers and are prone to leaks or breaching as a result of constant use, so you should take care to use quality materials and inspect the facilities on a daily basis.
There also are portable bins such as those made by Outpak Washout Systems. Their portable corrugated bins are 4 by 4 ft. (1.2 by 1.2 m) and 6 by 6 ft. (1.8 by 1.8 m) and their PVC washouts come in sizes up to 8 by 10 ft. (2.4 by 3 m) and can be used for up to 45 washouts.
For larger jobs, some in the rolloff industry are simply taking regular 10-yd. roll-off containers and lining those with plastic, according to Gold.
“And they’re using that as a concrete washout container. It may work for some and they may think that it’s leak-proof. But I don’t quite know if I agree with that,” Gold said.
For the most part Gold finds that when MBL Recycling is up against that type of a setup, general contractors will pay the little bit of extra cost to have a water-tight box that they don’t have to maintain or worry about, as MBL is taking care of getting it to the site, pumping it out when needed and taking it away when the job is through.
“We’ve been fortunate to have found general contractors who have wanted to do what’s best for the environment,” said Gold. “What’s really good is that there are a lot of them out there who want to do the right thing. It’s amazing.” CEG
Today's top stories