Chemical Engineering October 2011 - 15

Aeration blower
Raw water
Sedimentation
tank
Aeration tank
Recycled polluted sludge
Microbe
soup
Oxidizing
agent
" Bio-diet " for volume reduction
f polluted sludge
Slash sewage-sludge volumes
with this add-on digester
A
60% reduction in the sludge volume was achieved at the
sewage treatment plant of Noboribetu City, Hokkaido,
Japan, after installing a Bio-Diet SBD-1200 system from
Nippon Steel Kankyo Engineering Co. (NSKE; Tokyo, www.
nske.co.jp). The demonstration unit, developed at the Wakayama
Cleanup Center of Noboribetu City, was tested
during the summer.
In the Bio-Diet system (diagram), polluted sludge from
the sedimentation tank is continuously fed to a side reactor,
where a proprietary oxidizing agent is added to destroy
the cell walls of microbes in the sludge. The treated sludge
is returned to the aeration tank, where the biochemical oxygen
demand (BOD) is then reduced through aerobic digestion.
The Bio-Diet system is said to " drastically reduce " the
cost for processing polluted sludge, and offers low installation
cost, is easy to operate, requires no dewatering and has
no adverse effect on processed-water quality.
The company says Bio-Diet is especially suited to treating
polluted sludge with relatively low levels of inorganic
compounds, and can be applied to treating wastewater from
a wide range of the chemical process industries, including
food, beverage, brewing, chemical, oil-and-fats, dying and
fiber industries. The company is initially targeting applications
only in Japan.
A fast way to recover CO2
A
Due to global competition,
companies can only be successful
on the marketplace if they produce
outstanding quality cost effectively.
rapid pressure-swing-adsorption (rPSA) system to separate
carbon dioxide from fluegas is being developed by
W.R. Grace & Co. (Columbus, Md.; www.grace.com) and
three partners under a $3 million grant from the U.S. Dept.
of Energy (DOE; Washington, D.C.; www.energy.gov). The
goal is to develop a process that costs half as much as current
amine systems, whose cost is $50-70 per ton of CO2
captured, says Rob Harding, Grace's director of global R&D
for materials and packaging technology.
Grace is developing a multiple-bed rPSA system that
cycles in 1-30 s, or more than 10 times the speed of conventional
PSA, says Harding. CO2, approximately 10-12%
of the fluegas, will be adsorbed by one unit while another
is desorbing. The CO2 output gas stream will be >95% CO2.
The high cycle rate promises to reduce the size and cost of
the equipment to a small fraction of that of conventional
PSA units, he says.
One challenge is to develop an adsorbent tailored for
(Continues on p. 16)
High-quality control valves and
accessories with low cost of
ownership are what it takes for
economic production.
With 51 independent subsidiaries
and over 100 engineering and
sales offi ces spread across the
world, SAMSON ensures the safety
and environmental compatibility
of your plants on any continent.
Excess polluted sludge
2-3% of recycles
polluted sludge
Processed
water
Know-how
for Your Success
SAMSON AG · MESS- UND REGELTECHNIK
Weismüllerstraße 3
60314 Frankfurt am Main · Germany
Phone: +49 69 4009-0 · Fax: +49 69 4009-1507
E-mail: samson@samson.de
Internet: www.samson.de
SAMSON GROUP · www.samsongroup.de
A01051EN
Circle 47 on p. 70 or go to adlinks.che.com/35070-47
http://nske.co.jp http://adlinks.che.com/35070-47 http://www.grace.com http://www.energy.gov http://www.samson.de http://www.samsongroup.de
Chemical Engineering October 2011

Table of Contents for the Digital Edition of Chemical Engineering October 2011
