Let’s face it- construction sites can get seriously messy! This month we look at how a designated concrete washout area helps keep your worksite clean and safe while protecting our local waterways from pollution. Concrete washout, also called wash water or slurry, is the waste material created from cleaning out a pump truck, mixer, or anything else that was used to pour concrete. Getting rid of washout is trickier than most construction wastes because it cannot go into a dumpster as-is. Instead, a designated concrete washout area should be provided before cement pouring activities begin so there is no potential for discharge into a stream, ditch, storm drain, or any other water conveyance. After the slurry hardens, it can be disposed of or recycled into aggregate. There are multiple ways to provide a washout area, but the main goal is to have a waterproof pit or container that is easy to locate, use, and maintain. When possible, the area should be at least 50 feet away from storm drains, swales, and waterbodies. Signage and offering more than one washout area are highly recommended for larger developments. (Pictured above are some concrete washout areas seen while conducting our routine monthly inspections.) How does a concrete washout area promote workplace safety?
Concrete washout is a caustic and corrosive waste material with a pH of around 12. If an employee is exposed to washout, they can suffer serious skin irritation, chemical burns, and eye damage. Additionally, concrete washout contains toxic metals like Chromium, Nickel, Vanadium, and Zinc. Exposure in large amounts to these metals can cause long-term damage to the brain, lungs, kidneys, liver, and other important organs. Keeping waste contained to one or two designated areas will help minimize exposures and promote workplace safety. What kind of maintenance does a concrete washout area require?
Note: Washout waste is also created when using mortar, plaster, stucco, and grout and should also be disposed of properly. Additional Resources US EPA Concrete Washout Fact Sheet OSHA Concrete Hazards OEPA Rainwater and Land Development Manual Ohio EPA NPDES General Construction Permit (OHC000006)
0 Comments
BMP Blasts are issued every three months to highlight a sediment and erosion control best management practice. These blasts are designed to provide helpful insight and tips for properly designing, installing, using, and maintaining the control measure. Where and why is inlet protection required? Inlet protection is required on any storm drain at risk of receiving construction site run off. That said, there are limitations to the power of inlet protection. These controls are only designed to manage sediment from a drainage area of one acre or less. If greater than 1 acre of land is draining to one inlet, additional practices such as sediment traps or basins may be required. You may be thinking, “but, I have silt fence and a basin with a skimmer already!” Unfortunately, no one practice is 100% effective when it comes to sediment removal; they each have different strengths and weaknesses. For example, inlet protection has a limited ability to remove silts and clays but can effectively capture larger sand-size particles. The combined effect of each BMP helps to provide maximum sediment removal from storm flows prior to off-site discharge. In other words- perimeter controls, inlet protection, and a basin with a skimmer are likely all required (depending on the site and area of disturbance). Should I have inlet protection listed on my SWPPP? Yes! Inlet protection must be shown on the stormwater pollution prevention plan. While most contractors are familiar with the need for inlet protection, it is important that this is noted on plans to ensure any operator on-site is aware of the requirements and a proper maintenance schedule can be in place. The plan will also show the location all of these “at-risk” inlets so that protection gets installed on all drains and inspectors on-site can identify the location of these areas. Furthermore, it is important to show where these practices will be located in the plan review process to ensure that the drainage area is sized appropriately for the practice. There are certain considerations for placement as well. For example, practices that operate by blocking water from entering storm drains almost completely prevents sediment-laden discharges to entering the conveyance system, but they often result in ponding water. This ponding may be important to consider if these practices will be used on roadways that could flood during heavy rainfall. Are there different types of inlet protection? There are various methods of inlet protection specified in Chapter 6 of the Ohio Rainwater and Land Development Manual. Each method utilizes a combination of stone, wire mesh, and/or geotextile to filter sediment. Alternatively, pre-manufactured inlet protection devices may be used (and reused for the lifetime of the product). What kind of maintenance do inlet filters require?
Additional Resources OEPA Rainwater and Land Development Manual United States EPA Storm Drain Inlet Protection Fact Sheet Ohio EPA NPDES General Construction Permit (OHC000006) Sediment and erosion control maintenance needs are inevitable on construction sites. With the nature of construction activity and rainfall events, it is nearly impossible for controls to stay in perfect condition throughout the entire process. However, the more that your team stays on top of maintenance needs and acts proactively, the better the chances are to keep controls functioning and keep your site in compliance. General BMP Inspection Tips: The best way to stay on top of maintenance needs is to conduct routine inspections according to the guidance provided in the Rainwater and Land Development manual. Controls should be inspected daily for general condition and effectiveness. They should also be inspected after each rainfall event and during a prolonged rainfall. If controls aren’t being inspected on a regular basis, it is easy for small maintenance needs to compound and become larger issues over time. Below are 7 common BMP maintenance needs our urban inspectors see out on site and some tips for staying on top:
Fix Tips: If silt fence is downed, it may be able to be retrenched and wrapped around the stakes again. Ensure silt fence is properly trenched and pulled taught. If the geotextile material has been damaged, it will need replaced entirely. 2. Inlet Protection or Curb Stop Damaged Fix Tips: If using a basket or dam style inlet protection, ensure that capture device is secured underneath grate to prevent getting pulled into catch basin or swept into roadway. For curb inlets, ensure that curb stops are installed along rear of the grate to ensure that water cannot enter through the sides or top of the inlet. 3. Compost Filter Socks Flattened / Moved Fix Tips: Replace socks that have been torn or damaged beyond repair. If socks have just become flattened, refill with compost material until they are returned to the appropriate diameter. Encourage your team to use established construction entrances to prevent running over the socks. If the socks are moved for utility or other work on the lot, ensure that they are replaced in the appropriate location as soon as feasible. 4. Sediment Build Up in Street Fix Tips: Sweep the streets any time you notice a significant amount of tracking occurring. Establish a routine street sweeping schedule to prevent heavy accumulation on roadway. Ensure other practices (such as silt fence or filter socks, proper construction entrances) are in place and functioning to help stop sediment tracking in the first place. 5. Compost Filter Berms Blown Out Fix Tips: If you notice sediment is overtopping the berms, the sediment may need to be dug out away from the berm area. It’s best practice to keep the sediment deposit level below ½ of the height of mulch berms or silt fence. If a heavy rainfall knocks down a portion of the berm, make sure that berms are built back up to meet the specifications outlined in the RWLD manual. 6. Maintain Construction Entrance Fix Tips: ODOT 1/2s should be used for construction entrances. Smaller gravel tends to get swept into the roadway with sediment. If the incorrect aggregate is used, this will need to be revised to prevent off site tracking. If a construction entrance is regularly used, the aggregate may need to be replaced to provide ample area to kick sediment off wheels. 7. Concrete Washout Area Full / Needs Cleaned Up Fix Tips: Concrete washout pits should be emptied on a regular basis to prevent overflowing. If pits are dug out in the ground, they should be lined with a tarp to prevent leaching into bare soils. If the liner gets damaged or rolled up, it needs to be readjusted or replaced. The pit should have four walls around (typically lined straw bales). If the walls of the pit are compromised, they need to be rebuilt or replaced. BMP Spotlight Example from the Field: |
Details
Urban team BLOGEvery month, the Warren Co SWCD Urban Team dives deep into the world of land development as it relates to stormwater pollution prevention. The blog covers topics like erosion & sediment control best management practices (BMPs), state and local regulations, retention/detention basins, and the conservation of our natural resources. Stay up to date with Development Digest by signing up for WCSWCD Urban eNews!
Categories
All
Archives
April 2024
|