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:
  Polyacrylamide Roads--Design And Construction--Environmental Aspects--North Carolina Sedimentation Sedimentation And Deposition--North Carolina Stilling Basins Turbidity Water--Pollution--North Carolina--Prevention
• 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.
  
  
• Format:
  PDF
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha256:d0ae279840b0623e50edf3f15496bdfc744e75eead821ac08bff13383341c37e
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/17187/dot_17187_DS1.pdf
• File Type:
  [PDF - 68.42 KB ]