Water Environment & Technology (WE&T) is the premier magazine for the water quality field. WE&T provides information on what professionals demand: cutting-edge technologies, innovative solutions, operations and maintenance, regulatory and legislative impacts, and professional development.
any wastewater treatment professional will attest, grit can wreak havoc at a
treatment facility. Yet rarely is the nature of grit quantified or understood
before upgrade projects or new system designs are undertaken. Most process
upgrades require extensive site-specific wastewater data (such as total
suspended solids and biochemical oxygen demand), but the first step in the
treatment train often is designed without taking these into account. Yet poor
grit removal, handling, and processing equipment selection and performance can
have significant effects on downstream unit processes.
Shaking the sand out
systems often are part of the first generation of unit processes at water
resource recovery facilities (WRRFs). Some of these facilities are still in
use, but many have gone through upgrades and are approaching 20 to 25 years in
age. Because of the abrasiveness of grit, the operations and maintenance costs
for these systems can be high.
due to more-stringent effluent permit limits, many WRRFs are considering other
advanced treatment processes, such as biological nutrient removal, membrane
bioreactors, or other upgrades that can be adversely affected by the carryover
and accumulation of grit.
there is a greater need for grit systems to achieve higher removal
efficiencies, either through retrofits or outright replacement. Retrofits and
additions often can face several challenges, including limited space for
construction of new processes, difficulty in maintaining existing grit removal
during construction, phasing of tie-ins, and hydraulic limitations. Read more
All shook up
link deep-well injecting, water extraction, and earthquakes
Coming in the next issue:
Re-energizing the discussion
and resource recovery might be the catch phrase of the moment, but there’s a
good reason: Its importance becomes clear each month when the electric bill
arrives. Additionally, energy and resource recovery has elements of conserving,
protecting, and providing environmental services, so it is thematically in line
with water and sanitation services.
November issue examines several different aspects of energy and resource
recovery. The article, “Membrane bioreactors are not energy hogs,” evens the
playing field between membrane bioreactors and conventional activated sludge
for municipal wastewater treatment. By taking into account newer membrane
technologies and more stringent permit limits, the energy difference between
the two technologies shrinks considerably.
on the topic of leveraging technology, “Harnessing big data for energy and
asset management,” explains how using data science can improve energy
efficiency and recovery. Information about what’s happening in a process or
facility is good; organizing that information into actionable knowledge is
further toward recovery, “A smooth blend” details how a utility improved its
operations and boosted its methane gas production by adding excess fats, oils,
and grease into its digesters. Minor improvements, simple standard operating
procedures, and meaningful operational data led to energy production without an
increase in staff.
on what’s next once the energy is produced, “Spreading the wealth” tells how a California
utility set up the agreements and deals to sell surplus renewable energy. This
type of sales requires such things as renewable-generator certifications,
registrations, and coordination with various regulatory authorities.
Also in this issue
in sewer-flow monitoring.
A Department of Watershed Management division in Atlanta
invents a “sewer boat” to monitor flows and bypass obstacles.
Bienvenidos to the
The world’s largest algae and wastewater project in Spain is showing positive
Despite public education campaigns, London continues to battle grease and wet
wipes clogging the city’s sewers.
instrumentation set for growth.
Automated instruments can help streamline
plant operations and save on labor costs, but skilled operators still will be