of a second fluid-bed sewage sludge incinerator at T.Z. Osborne Water
Reclamation Facility and its compliance with the new MACT emission requirements
Don Howard, Ky Dangtran, and Levent Takmaz
2007, the City of Greensboro, N.C., began a project to add a second fluid-bed
wastewater residual incinerator at its T.Z. Osborne Water Reclamation Facility.
The project would provide the capacity to handle an additional 59 dry Mg/d (65
dry ton/d) of primary solids — the existing fluid-bed incinerator can handle 54
dry Mg/d (60 dry ton/d) — and to replace the existing fluid bed during
initial startup and performance testing in September 2011, the new unit
satisfied the existing air quality emission requirements. However, the U.S.
Environmental Protection Agency (EPA) finalized its new maximum available
control technology (MACT) emission requirements for sewage sludge fluid-bed
incinerators in March 2011. EPA’s new emission limits were very strict,
compared to previous emission limits.
new limits required retesting the emissions from the incinerator to ensure that
they were in compliance and making process changes — both within the
incinerator and downstream — to meet the new limits. Read full article (login required)
pursue the first certified methodology for carbon credits given to a wetland
municipal effluent assimilation system in Louisiana
Sarah K. Mack, Robert R. Lane, and John W. Day
restoration is critical to combating wetland loss. It also is an effective
climate change mitigation strategy, because it enhances carbon sequestration
and avoids carbon releases that would occur in the absence of restoration
of Degraded Deltaic Wetlands of the Mississippi Delta,” certified by the
American Carbon Registry (ACR; Arlington, Va.), is the name of the first
carbon-offset methodology that is specifically focused on U.S. wetlands. It
also is the first wetlandoffset methodology in the world that is applicable on
a large scale to broadly address wetland restoration through numerous eligible
techniques, including hydrological management, reforestation, and
An environmental consulting firm applied the wetland methodology to the
Luling Oxidation Pond Wetland Assimilation System — wetlands near Luling, La. —
to conduct the first pilot project in the U.S. to determine the true costs,
benefits, and barriers to implementation. It is also the first offset project in
the U.S. that demonstrates the ability to create public–private partnerships
that leverage carbon finance. Read full article (login required)
organic wastes yield greater hydrogen and methanewith ultrasonication
Elsayed Elbeshbishy, Hisham Hafez, Ahmed Eldyasti, and George Nakhla
digestion (AD) is a proven technology for the treatment of various organic
wastes and production of methane. However, the rate-limiting step in AD is
hydrolysis, or solubilization, where the cell wall is broken down, allowing
organic matter inside the cell to be available for biological degradation. The
AD process may therefore be improved if hydrolysis can be enhanced.
Pretreatment often is required to release lignocellulosic material and thus
accelerate the degradation process via waste solubilization.
increasingly is used as a pretreatment method for AD due to its ability to
enhance solubilization. The use of ultrasonication in solids pretreatment not
only enhances hydrolysis but also improves the operational reliability of
anaerobic digesters, decreases odor generation, and enhances solids dewatering.
Read full article (login required)
Operations Forum Features
grit-slurry problems. Now what?
strategies for successful grit-slurry pumping systems serving large combined
purpose of preliminary treatment systems is to remove debris and grit from
influent and protect downstream processes from these damaging materials. While
screening devices remove debris, grit-removal processes remove smaller grit
particles. Grit particles that accumulate and concentrate at the bottom of a
grit-removal system are commonly referred to as “grit slurry.”
a process that is intended to prevent or reduce downstream maintenance often is
plagued with maintenance issues. Frequent problems include plugged grit-slurry
collection sumps, plugged grit-slurry piping, failed grit-slurry pumps, and
plugged grit-slurry concentrators.
Adherence to sound design and operating strategies can avoid or minimize
the occurrence and severity of problems frequently encountered by grit-slurry
extraction, pumping, and processing systems. Read full article (login required)