cylinders were attached to the underside of the massive gates (117 ft each) to provide
a positive control mechanism for maintaining the level of Lake Brazos. This
modification, while expensive to maintain, has restored quite a bit of reliability.
Through decades of modifications and expensive maintenance, it was time to replace
the structure with a new dam, which will offer reliability while requiring less
maintenance. The new dam will be a concrete labyrinth weir. The new dam is
scheduled for completion in fall 2007.
The City of Waco remains committed to providing a safe and plentiful supply of
water for its citizens. Work has begun on 80 million USD in improvements to the
water treatment system. The first phase has been completed with the completion of
construction on the 42
00 water distribution line and upgrades at the Mount Carmel
Water Treatment Plant. This will improve the treatment capacity at that plant from
45 to 66 MGD. Similar improvements will take place at the Riverside Plant, and
when the entire project is completed, the City of Waco will be able to treat a
maximum of 130 MGD of water.
The City of Waco is also making the transition to a new dissolved air flotation
(DAF) treatment process. This will address issues with the taste and odor problems
caused by by-products of algae in the North Bosque River Watershed. The second
phase of the Water Quality and Quantity project is designed to dramatically improve
the taste of the finished water. In order to complete this task, the City of Waco is
constructing a new clarification facility, featuring DAF for the removal of algae and
other suspended particles from the raw water supply. DAF is particularly effective
on waters with significant amounts of lightweight particles such as algae. Algae are
the primary source of taste and odor-causing compounds in Texas waters.
DAF works by attaching air bubbles to particles suspended in the raw water and
floating them to the surface of a tank for removal. The process includes flocculation
to bind particles suspended in the raw water into larger flocs that can more easily be
removed, a saturator that entrains air into a side stream for injection into the process,
an air nozzle header that releases extremely fine air bubbles that attach to the
flocculated particles, a skimmer which removes the suspended particles after they
float to the surface of the basin, and effluent laterals which collect the clarified water
off the bottom of the basin.
The odor-causing compounds MIB and geosmin are found inside the algae cells
and get released to the water when the algae is killed or damaged. By removing the
algae at the lake site (see Fig. 7.18) before it has a chance to be killed or damaged
during piping to the treatment plant or the water treatment process itself, water
quality will be significantly improved. The reduced levels of MIB and geosmin in the
raw water once the algae is removed will allow any residual taste and odor compounds to be more easily removed in later stages of the treatment process. After DAF
clarification, the water will be treated with chlorine dioxide for primary disinfection
and then sent to the two treatment plants where it will be filtered through sand and
granular activated carbon for removal of residual taste and odor-causing compounds
and any remaining suspended materials.
300
L. K. Wang et al.
a positive control mechanism for maintaining the level of Lake Brazos. This
modification, while expensive to maintain, has restored quite a bit of reliability.
Through decades of modifications and expensive maintenance, it was time to replace
the structure with a new dam, which will offer reliability while requiring less
maintenance. The new dam will be a concrete labyrinth weir. The new dam is
scheduled for completion in fall 2007.
The City of Waco remains committed to providing a safe and plentiful supply of
water for its citizens. Work has begun on 80 million USD in improvements to the
water treatment system. The first phase has been completed with the completion of
construction on the 42
00 water distribution line and upgrades at the Mount Carmel
Water Treatment Plant. This will improve the treatment capacity at that plant from
45 to 66 MGD. Similar improvements will take place at the Riverside Plant, and
when the entire project is completed, the City of Waco will be able to treat a
maximum of 130 MGD of water.
The City of Waco is also making the transition to a new dissolved air flotation
(DAF) treatment process. This will address issues with the taste and odor problems
caused by by-products of algae in the North Bosque River Watershed. The second
phase of the Water Quality and Quantity project is designed to dramatically improve
the taste of the finished water. In order to complete this task, the City of Waco is
constructing a new clarification facility, featuring DAF for the removal of algae and
other suspended particles from the raw water supply. DAF is particularly effective
on waters with significant amounts of lightweight particles such as algae. Algae are
the primary source of taste and odor-causing compounds in Texas waters.
DAF works by attaching air bubbles to particles suspended in the raw water and
floating them to the surface of a tank for removal. The process includes flocculation
to bind particles suspended in the raw water into larger flocs that can more easily be
removed, a saturator that entrains air into a side stream for injection into the process,
an air nozzle header that releases extremely fine air bubbles that attach to the
flocculated particles, a skimmer which removes the suspended particles after they
float to the surface of the basin, and effluent laterals which collect the clarified water
off the bottom of the basin.
The odor-causing compounds MIB and geosmin are found inside the algae cells
and get released to the water when the algae is killed or damaged. By removing the
algae at the lake site (see Fig. 7.18) before it has a chance to be killed or damaged
during piping to the treatment plant or the water treatment process itself, water
quality will be significantly improved. The reduced levels of MIB and geosmin in the
raw water once the algae is removed will allow any residual taste and odor compounds to be more easily removed in later stages of the treatment process. After DAF
clarification, the water will be treated with chlorine dioxide for primary disinfection
and then sent to the two treatment plants where it will be filtered through sand and
granular activated carbon for removal of residual taste and odor-causing compounds
and any remaining suspended materials.
300
L. K. Wang et al.