ROBINS AIR FORCE BASE, Ga. -- Construction projects frequently require pouring of new concrete and painting of surfaces. Concrete trucks must be washed out, often on-site, shortly after the concrete pouring is complete to remove remaining concrete before it hardens. In addition, washing is required for hand tools used for concrete construction and painting tools to maintain brushes, rollers, etc. Concrete pouring, truck washing and tool washing result in the production of waste slurries and wash water that must be properly managed and should not be allowed to enter the storm drain system. When slurries and wash waters are discharged to the surface, they can eventually run off into the storm water conveyance system, which discharges to streams, lakes, wetlands and rivers where aquatic life can be impacted.
Concrete slurries and wash waters typically have a high pH around 12 standard units, making them dangerous for aquatic life. Aquatic habitats for freshwater are considered safe in the range of 6.5 to 9 s.u. Caustic wash water can harm fish gills and eyes, and can interfere with reproduction. Paint particles can clog fish fills, and paint contains pigment that can cloud the water reducing visibility for fish and photosynthesis for plant species. Paints considered as “environmentally friendly” may also have these effects. Concrete and paint can also contain heavy metals, which can impact aquatic life.
A common solution for management of concrete and paint waste is to use a leak proof washout container. Containers could include a lined, excavated pit or a commercially available “outpak” made of fiberboard or plastic. Concrete and paint can be washed into the container, which will hold the liquids and solids. Solids can be physically removed once hardened, and liquids can be properly treated. Containers should not be overfilled and should be cleaned out once 75% of the capacity has been reached to avoid overtopping during a rain event. Washouts should be regularly inspected for spills and leaks. Any spills or leaks should be cleaned up immediately upon observation.
To avoid the environmental hazards associated with concrete and paint waste, be sure to:
- Limit the amount of concrete and paint purchased to only what is required to reduce waste
- Do not wash construction tools onto the ground, in the lawn, or into storm drains
- Properly dispose of concrete and paint waste in accordance with local regulations
- Utilize BMPs for concrete and paint washout on construction sites
- Maintain BMPs to avoid overflow or leaking and discharge to the storm drain
- Protect storm drains around construction sites
For more information, call (478) 222-2526.
Stormwater Straight Talk is a quarterly column intended to educate and inform base personnel and families about stormwater management.