WASTWATER
RECYCLING
AND
PRE-TREATMENT
COMMERCIAL
TRUCK
WASHING
OPERATION
Biological
Treatment
Summary
The
Situation
A large
commercial
truck
washing
operation
was
in need
of a
wastewater
recycling
and
pre-treatment
system.
This
truck
wash
consists
of (8)
wash
bays,
four
full-service
and
four
self-service.
Flow
rates
from
their
13 hand
held
high-pressure
washing
systems
(5 gpm
ea.)
can
reach
65 gpm.
The
customer
was
discharging
100%
of their
wastewater
to sanitary
sewer.
The
local
P.O.T.W.
was
surcharging
them
for
excess
TSS,
BOD
and
several
heavy
metals
costing
thousands
per
month.
With
water
costs
rising
frequently
and
a worsening
drought
it made
sense
to the
owners
to recycle
as much
water
as possible.
Wastewater
recycling
systems
in car
and
truck
washes
is generally
an extremely
fertile
environment
for
naturally
occurring
bacteria
to form.
Ozone,
hydrogen
peroxide
and
chlorine
disinfectants
are
usually
used.
Over
time
these
destroy
the
customers
vehicles
and
car
washing
equipment.
The
Solution
A wastewater
treatment
system,
model
"Extreme
Clean,"
was
installed.
The
Extreme
Clean
is capable
of providing
recycled
water
back
to the
washing
equipment
at sufficient
flow
rates.
Filtration
methods
include
after
solids
settling,
oil
coalescing,
active
skimming
and
dual
filter
media
polishing.
BZT®
Waste
Digester
was
seed
dosed
into
the
system
at a
rate
of 1
lb.
Per
1000
gallons
of water
volume
Maintenance
doses
are
provided
in stabilized
liquid
form
using
an automatic
dosing
system.
Maintenance
rates
were
set
at -
one
3 oz.
dose
per
500
gallons
of water
volume
each
day.
The
Results
The
system
has
been
in operation
for
five
months
with
no smell.
Resulting
water
tests
are
shown
below.
|
PARAMETER
|
BEFORE
|
AFTER
|
PERCENTAGE
REDUCTION
|
|
Biological
Oxygen
Demand,
mg/L
|
324
|
94.4
|
70.86%
|
|
Total
Suspended
Solids,
mg/L
|
8770
|
219
|
97.50%
|
|
Oil
and
Grease,
mg/L
|
46
|
24.4
|
46.96%
|
|
Petroleum
Based
Oil
&
Grease,
mg/L
|
22.7
|
11.5
|
49.34%
|
|
Silver,
mg/L
|
0.06
|
0.004
|
93.33%
|
|
Aluminum,
mg/L
|
153
|
1.8
|
98.82%
|
|
Arsenic,
mg/L
|
0.998
|
0.046
|
95.39%
|
|
Cadmium,
mg/L
|
0.26
|
0.001
|
99.62%
|
|
Chromium,
mg/L
|
0.284
|
0.013
|
95.42%
|
|
Copper,
mg/L
|
7.56
|
0.4
|
94.71%
|
|
Molybdenum,
mg/L
|
0.015
|
0.005
|
66.67%
|
|
Nickel,
mg/L
|
0.466
|
0.035
|
92.49%
|
|
Lead,
mg/L
|
1.76
|
0.039
|
97.78%
|
|
Selenium,
mg/L
|
0.19
|
0.015
|
92.11%
|
|
Zinc,
mg/L
|
8.45
|
0.31
|
96.33%
|
|
Mercury,
mg/L
|
0.0079
|
0.0001
|
98.73%
|
|
|