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What
does a Biosystems Engineer do?
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Steven
L. Belcher
Biosystems Engineering (B.S. 1998)
Natural Resources & Environment Concentration
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My
education has served me well in performing my job duties. My employer,
Phoenix Process Equipment Company, is generally pleased with my ability
to process large sets of data and my ability to report the results from
laboratory and field tests in a thorough, clear, and concise manner.
I thank the professors that insisted that we use and practice our technical
writing skills with weekly lab reports. I also thank a senior year course
that emphasized that we were assuming professional positions and we
should present ourselves professionally in the way we act, speak, and
perform our jobs. That is seemingly a subtle point, but it has made
and will continue to make a great difference in my career.
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have I used my education? |
After
graduation, I was living in Louisville, KY, and found Phoenix Process
Equipment Company through word of mouth. Phoenix designs, manufactures
and markets equipment for separating liquids and solids found in
a variety of waste sludge and slurries (see our website at http://www.dewater.com).
Applications include municipal, pulp & paper, chemical, food,
foundry, aggregate, mining and general industrial markets. I was
hired as a Process Engineer. The Process Engineer provides direct
support to Phoenix activities in the performance of laboratory tests
and equipment demonstrations that are simulations of Phoenix equipment
at customer facilities showing Phoenix's ability to meet the customer's
requirements.I am often called upon |
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to provide technical
assistance in customer problem investigations and solution development.
I interact directly and indirectly with the customer through requests
for assistance from the Sales and Marketing and the Service Departments.
The chemical reactions that allow the equipment to work are very important
to the ability of Phoenix to provide the customer with a solution to their
dewatering problems. I work with the customer to understand the problem
and with chemical company representatives to select the proper polymer
and process flows.
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I spend time
in my office and in our lab. I travel frequently to customer sites.
The use of our equipment often leads directly or indirectly to
environmental protection. The process performed by our equipment
often helps customers meet environmental regulations regarding
water quality and stream discharge. A valuable byproduct frequently
results from the dewatering/separation process, as well. The environmental
benefits are different for each type of sludge or slurry that
we dewater. In the aggregates market, customers are able to conserve
water and reduce their freshwater usage by recycling the recaptured
water back into their washing operations. With the use of hydroclones,
the
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customer is able to recover valuable sand product that would otherwise
accumulate in the settling ponds. They are also able to conserve
their land usage by eliminating their large slurry pond systems
with a total fines dewatering system that occupies much less area.
Often, the existing slurry ponds tie up valuable mining resources.
Also, the dewatered solids are in a state more amenable to moving
and handling and require less volume for their ultimate sale or
disposal. In the municipal sludge market, there are regulations
that must be met for the disposal of the dewatered solids. The cake
must appear surface-dry, be handlable, and have specified minimum
moisture content. The recovered water is returned to the water treatment
process for eventual return to the environment. These benefits are
also applicable for many other smaller markets.Recently, I traveled
to a Southern California aggregate plant (quarry) to do a field
demonstration of our mobile fines dewatering system. The following
is a general description of the aggregate plant, the goals of testing,
and the pilot-plant equipment that was tested.
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Overview
This System consists of a HG Separator, HiFlo™ Thickener, and Model
WX-1.2-H Belt Filter Press. The HG Separator Uses high efficiency hydrocyclones
followed by a high intensity vibrating screen to separate most of the
plus 400 mesh particles from the slurry stream. The HiFlo™ Thickener
is a high-rate circular thickener that concentrates the solid material
into a reduced volume and provides a clear filtrate for process reuse.
The belt filter press dewaters the solids into a dry, stackable cake
that can easily be handled by a loader, conveyor, or similar means.
Each of these components is discussed in detail later in this report.
The feed slurry is pumped from a sump containing a flow of wash water
after it has passed the wash towers and before it is discharged into
a series of settling ponds.
The
on-site pilot study was conducted to demonstrate the effectiveness of
the PHOENIX Fines Recovery System at the plant, collect sufficient data
to select full-sized equipment, and allow plant personnel to view the
equipment.
Plant
Description
This Southern California aggregate plant produces various quantities
and grades of rock, sand, and fill material. During the weeks of testing,
the plant wastewater was measured to be approximately 4,900 gpm. This
slurry carries 12 to 283 tons per hour of fine solids. The flow of solids
fluctuates depending upon plant operations.
The waste slurry
from the plant comprises three waste streams from three washing operations.
Currently, the waste slurry is clarified through a series of four settling
ponds. An emulsion anionic flocculent is mixed with the waste stream
as it enters Pond 1. As Pond 1 accumulates solids, a dragline removes
the settled layer from the pond. In most cases, this material is handled
four times before reaching the final destination. While waiting to be
handled, the mud dries. By the fourth handling, it is approximately
73.5% solids.
The plant goal is
to minimize the quantity of fines going to their settling ponds, recover
the solids, and sell them as a product. Reclaiming clear water for use
as plant wash-water or discharge is also desirable.
Pilot Plant Description
The above flow diagram
of a fines dewatering system shows a portion of the slurry waste stream
was pumped from the plant's sand screw to a mix tank that is used to
feed the HG Separator (Line A). Slurry was then pumped (Line B) from
the sump to the hydrocyclone inlet, where the flow was measured and
controlled. The hydrocyclone overflow reported to the high rate thickener
(Line E). The hydrocyclone underflow (Line C) reported to the vibrating
screen, where a cake (Line D) averaging 79% solids was obtained. This
material is the coarser fraction of the original slurry stream and is
marketable sand. A portion of the hydrocyclone underflow passed through
the vibrating screen and returned to the sump.
The hydrocyclone
overflow (Line E, the finer fraction of the original slurry stream)
was treated with polymer and fed the HiFlo™ Thickener. The polymer
addition caused the solids to settle into a bed of thickened solids,
leaving a clear water overflow (Line F) that was discharged to the pond.
The underflow (Line G, approximately 35% solids) from the thickener
was pumped to the belt filter press where it was diluted to 25% solids
and treated with polymer to agglomerate the solids and to release free
water before it reached the feed box. After plows, a wedge section,
and a series of tensioned rollers, the dewatered cake (Line I) was discharged
to the ground in a dry, stackable state with approximately 70% solids.
The belt filter press filtrate (Line H, the water recovered from the
thickened slurry) was recycled to the thickener.
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