Concrete Waste Concerns, Why Does It Matter?
The residue and contaminants from washing concrete trucks, pumps, mixers, chutes, hand tools, and wheelbarrows is called “concrete washout”. Products like grout, mortar and stucco and activities such as saw cutting, coring, grinding and grooving can also result in concrete washout. This type of waste is highly alkaline, contains high levels of chromium, and is caustic and corrosive. When not managed properly it can pollute surface water and groundwater by changing its pH, increasing the toxicity of other substances, and reducing water clarity. Each of these changes is detrimental to aquatic life and their habitats.
Concrete washout that is dumped on the ground and absorbed into the soil can substantially alter the soil and inhibit future plant growth.
REQUIREMENTS / TIPS
• Train employees and subcontractors so they do not dump concrete washout on the ground or allow it to enter storm drains, open ditches, streets and waterways.
• Washout facilities should only be for chute and tools washing. Truck washout and remaining concrete should be taken back to the plant.
• Rinsing the truck should be done in an area where the contaminated water is not allowed to enter storm drains, open ditches, streets and waterways.
• On smaller jobs a portable concrete washout facility is acceptable. For construction sites use the standards set forth in the Iowa Statewide Urban Design and Specifications (section 11,050) https://intrans.iastate.edu/app/uploads/sites/15/2018/09/Division_11.pdf
• Install signs for locating the washout.
• Washouts should be large enough to contain liquid and concrete waste generated by washout operations.
• Cover the washout area if there is a risk of overflows during rainstorms.
• Keep washout areas a minimum of 50 feet from storm drains, open ditches and water bodies. Locate in areas where construction traffic won’t damage them
• Replace plastic liner (10 mil) after every cleaning.
• Construct a stabilized construction entrance if washout isn’t along stabilized surface to avoid tracking onto the street.
• Inspect washout daily to assure sidewalls are intact, leaks are absent, liner is not torn or ripped and there is adequate capacity remaining.
• Washout facilities must be cleaned or new facilities constructed, once the washout container is 75% full.
• Under no circumstances should a washout facility be allowed to overflow.
Concrete Washout Requirements
As outlined in the IDNR General Permit NO. 2, NPDES Permit for Storm Water Discharges from Construction Site Activities, concrete waste is considered a non-storm water discharge and therefore must be prohibited from entering “waters of the state”.
Why Care About Clean Water?
Storm water pollution is one of the greatest threats to Iowa’s creeks and rivers. Clean water means safe drinking water, places for recreation, commercial opportunities, healthy wildlife habitats, and adds beauty to the landscape. Rain washes pollution from streets, parking lots and lawns into storm sewers and drainage ditches then directly to our streams, rivers and ultimately, the ocean.
City of Urbandale
3600 86th Street
For More Information about the City of Urbandale’s Storm Water Programs go to: https://www.urbandale.org/256/Storm-Water