Managing Concrete Washout on Construction Sites

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Peter The Minnesota Pollution Control Agency Saint City of (MPCA) issued a new construction require- ment in 2008. It contains specific new regulations for managing concrete washout on construction sites:

“All liquid and solid wastes generated by concrete washout operations must be con- tained in a leak-proof containment facility or impermeable liner. A compacted clay liner that does not allow washout liquids to enter ground water is considered an impermeable liner. The liquid and solid wastes must not contact the ground, and there must not be Managing runoff from the concrete washout opera- Concrete tions or areas. Liquid and solid wastes must be disposed of properly and in compliance Washout with MPCA regulations. A sign must be in- stalled adjacent to each washout facility to City of Saint Peter inform concrete equipment operators to util- Department of Public Works Stormwater Utility ize the proper facilities”. 405 West Saint Julien Street Stormwater Saint Peter, MN 56082-1874 Utility The City of Saint Peter is requiring that all Phone: 507-934-0670 Fax: 507-934-1358 www.saintpetermn.gov permitted sites follow MPCA guidelines and email: [email protected] contain a concrete washout. These washouts Phone: 507-934-0670 will need to be inspected weekly by the per- mit holder. Management Tips Concrete Concerns

The residue and contaminants from  Train employees and subcontractors  Inspect the containment areas washing concrete trucks, pumps, mixers, so they do not dump concrete wash- daily to ensure the sidewalls are chutes, hand tools, and wheelbarrows is called out on the ground or allow it to enter intact, leaks are absent, and ade- storm drains, open ditches, streets, quate capacity remains. “concrete washout”. Cementitious products and waterways.  Cover the containment area be- (like grout, mortar, plaster, and stucco) and  When feasible, truck washout should fore rainstorms to prevent over- activities (saw cutting, coring, grinding, and occur at the concrete plant. flows. grooving) can also result in concrete washout.  When washout is needed on a con-  Washout facilities must be struction site, use temporary storage cleaned, or new facilities con- This type of waste is highly alkaline facilities large enough to contain the structed and ready for use, once (pH12), caustic, and corrosive. When it is not liquid and concrete waste generated the washout container is 75% full. by washout operations.  Hardened solids can be crushed properly managed, it can pollute surface wa-  Keep washout areas at least 50 feet and hauled away for recycling or ter and groundwater by changing its pH, in- from storm drains, open ditches, and disposed of properly and must creasing the toxicity of other substances, water bodies and install signs in- comply with MPCA disposal re- and reducing water clarity. Each of these structing operators to use the facil- quirements. ity.  Place new plastic in the contain- changes is detrimental to aquatic life and  One containment option is to use ment facility each time it is their habitats. manufactured, watertight, portable cleaned and complete other washout containers. needed repairs before using the Concrete washout that is dumped on  Alternatively, a plastic-lined contain- containment facility again. the ground and absorbed into the soil can ment area such as a holding pit, ber- substantially alter the soil and inhibit future med basin, roll-off-bin, or portable plant growth. tank that prevents runoff from en- tering it can be constructed. The liner should follow the Minnesota Pol- lution Control Agency (MPCA) guidelines.  When pavement is absent, construct a stabilized vehicle entrance to the containment area.  Keep containment areas away from construction traffic to reduce the likelihood of accidental damage and spills.