Stilling basin design and operation for water quality.

Details

• Creators:
  McLaughlin, Richard A.
• Corporate Creators:
  North Carolina State University. Soil Science Dept.
• Subject/TRT Terms:
  • Stilling basins
  • Turbidity
  • Sedimentation
  • Stilling basins
  • Polyacrylamide
  • Sedimentation and deposition--North Carolina
  • Water--Pollution--North Carolina--Prevention
  • Roads--Design and construction--Environmental aspects--North Carolina
• Publication/ Report Number:
  FHWA/NC/2006-38
• Resource Type:
  Tech Report
• Geographical Coverage:
  North Carolina
• Edition:
  Final report; Aug. 2005-Oct. 2006.
• Corporate Publisher:
  North Carolina. Department of Transportation. Research and Analysis Group
• Abstract:
  Many construction projects involve the need to pump turbid water from borrow pits or ; other excavations into stilling basins or sediment bags prior to discharge. The design and ; operation of these basins needs to be optimized to provide the best water treatment prior to ; discharge. This project was designed to provide an evaluation of stilling basin designs and ; polyacrylamide (PAM) injection to minimize turbidity in discharged water. Of particular ; interest were difficult to settle Coastal Plain sediments containing highly charged clays ; (smectite/montmorillonite). The use of stilling basins did not result in significant reductions in ; turbidity in water pumped from the simulated borrow pits in these types of soils. These were ; not flocculated significantly by anionic PAM but can be flocculated by neutral or cationic PAM. ; In field tests, the flocculation process reduced turbidity regardless of the inclusion of either ; porous coir or rock baffles. However, at least one baffle is recommended when PAM is being ; used in case floating flocs are formed. Turbidity was reduced from the 500-800 NTU range to ; < 30 NTU in many cases, especially for the cationic PAM. Similar reductions were achieved ; using a sediment bag. Toxicity tests indicate the relative PAM toxicity was cationic > anionic ; > neutral, and was not affected by turbidity. The neutral PAM was almost as effective as the ; cationic PAM and was even less toxic than the anionic PAM, so it may be an alternative ; where the anionic PAMs that are available will not work.
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• Format:
  PDF
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/17187/dot_17187_DS1.pdf
• File Type:
  [PDF - 68.42 KB]
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha256:d0ae279840b0623e50edf3f15496bdfc744e75eead821ac08bff13383341c37e