Health Education Services, 1997 Edition; and Water Quality and
Treatment , Chapter 5, "Air Stripping and Aeration," AWWA, fourth
Sludge Removal . Sludge removal is generally with
mechanized sludge collectors, although it may be manual in some
installations. If manual, provide at least two basins so that
one basin may be taken out of service for cleaning without
interruption of operation. Provide for hydraulic removal of
settled solids by draining and flushing if possible, otherwise
by manual load -and -haul. Refer to par. 6.11 for further
Coagulation and Sedimentation. Refer to Water
Treatment Plant Design , Chapter 6, "Mixing, Coagulation and
Flocculation," Chapter 7, "Clarification," AWWA, third edition;
and Water Quality and Treatment, Chapter 6, "Coagulation
Processes: Destabilization, Mixing, and Flocculating," Chapter
7, "Sedimentation and Floatation," AWWA, fourth edition.
Materials of Construction
Concrete. Use concrete for all permanent
installations constructed on-site.
Steel. Use steel only for temporary units,
factory prefabricated units, or small circular basins. It may be
used for internal parts of a solids contact reactor, but for
permanent installations, provide adequate corrosion protection.
Filtration. Refer to Water Treatment Plant Design ,
Chapter 8, "High Rate Granular Media Filtration," Chapter 9,
"Slow Sand and Diatomaceous Earth Filtration," AWWA, third
edition; and Water Quality and Treatment , Chapter 8,
"Filtration," AWWA, fourth edition.
Filtered Water Storage . Provide filtered water
storage (clear well) in accordance with Recommended Standards
for Water Works, Part 7, "Finished Water Storage," Health
Education Services, 1997 edition. Chlorine contact time (CT)
should be in accordance with the requirements of the 40 Code of
Federal Regulation (CFR) Part 141, and U.S. EPA National