Environmental Science & Engineering - www.esemag.com - July 2005
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Advanced technology for the treatment of food industry process water
By Manuel A. Cuenca and Maggie Stewart
The food industry is one of the largest consumers of
water from the industrial sector. The cost of the
treatment of food processing wastewater is very
high because of the high BOD levels. Ecotechnos
Inc., a Canadian manufacturer of equipment for the treatment
of industrial wastewater, has created a series of
advanced wastewater treatment units commercially known
as Aquacan®.
The treatment capacity of the plants ranges from 3 m3/day
to more than 600 m3/day and they are designed to guarantee a
long life expectancy to each of the components. Because of
the modular configuration of the units, it is possible to expand
the treatment capacity as the financial resources of a company
permits. The Environmental Technology Verification
Program (ETV) has certified the high performance exhibited
by these units.
Case study: Treating winery
wastewater
The treatment of winery wastewater is based on the
process characteristics observed near the distributor of fluidized
beds as well as on the fixed film processes. The former
is represented by a combination of microbubble diffusers
and sedimentation sections and the latter is represented
by a system of biodiscs. The unit tested was an Aquacan
6000, generically named Active Biological Contactor
(ABC). The plant consisted of a primary clarifier and a
microbubble aeration section, a rotating biological contactor
(RBC) with proprietary discs that have enhanced interfacial
area, and a secondary clarifier with another microbubble
aeration section. The assembly is compact and robust and,
due to its modular configuration, a treatment plant can be
progressively expanded as the needs for increased capacity
or influent strength arise.
Results
a) Organic matter removal. Aquacan 6000 can remove an
average of 96% BOD5 at an organic loading of less than 630
g/m3day. As the loading increases, the BOD5 and CBOD
removal decrease. With an organic loading of more than
11,500 g/m3day, the BOD5 and CBOD removal was approximately
70%. This percentage can be substantially improved
by installing a second unit in series.
An inadvertent bleach discharge from the cleaning operations
in the winery produced a toxic shock in the treatment
system. The recovery period from the toxic shock was
remarkably short. In just 10 days, the unit recovered its
steady performance, removing an average of 93% of BOD5
and CBOD.
b) Total suspended solids removal. It was observed that
80% of the total suspended solids were removed at loadings
between 250 to 3,250 g/m3day.
c) Sludge removal. During the testing period of four
months, the unit treated 217 m3 of high-strength winery
wastewater. An average BOD loading of 2,500 mg/L produced
420 L of sludge with 5% solids.
d) Mechanical performance of the unit. The Active
Biological Contactor includes a proprietary RBC unit. This
unit has been designed with Hexacell™ technology, which
reduces the torque effects on the shaft. In that regard, and
after 1,000,000 rotations with a load of biomass of 250 lbs
the performance of the shaft met the most severe expectations.
Manuel A. Cuenca, Ph.D., P.Eng., and Maggie Stewart,
B.Eng., are with Ecotechnos Inc., Toronto, Ontario.
Contact maggies@ecotechnos.com.
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