Successful Sludge Reduction Program in 3 Acre Section
of 300 Acre Lake: Lake Musconetgong, NJ
Lake Musconetcong is located on the border of Morris County and Sussex County, New
Jersey, and is part of Hopatcong State Park, which is administered by the New Jersey
Department of Environmental Protection. The Musconetcong River flows through the
lake.
The lake covers 329 acres (1.3 km²), with a mean depth of approximately 5 feet (1.5 m)
and a maximum depth of 10 feet (3.0 m). The lake's watershed covers 14,000 acres (57
km²). Lake Musconetcong is downstream of Lake Hopatcong, the largest lake in New
Jersey and is part of its watershed.
Overview of Lake Musconetgong
Since this lake is shallow, it has experienced ongoing problems with weeds (especially
near the shore line), and accumulated organic sediment has become a pressing issue.
Over the years, the algal and weed blooms, ongoing herbicide applications, and
resulting residue from die-offs has resulted in considerable bottom sediment problems.
EcoBac for Sludge Reduction
EcoBac, a prepared blend of sludge digesting beneficial bacteria and probiotics, has
been used successfully around the world to solve sludge build up problems. In this
situation, with a known sludge problem around the lake, the authorities chose a specific
section of the lake to test the sludge reducing ability of EcoBac.
In the above chart, and comparing this to the lake overview (previous page), it is clear
that a localized zone of about 3 acres was chosen for evaluation.
Using the sludge judge (shown at left), the clear polycarbonate tube
is slowly inserted into the lake all of the way to the bottom. When the
sludge judge reaches the bottom of the lake, a bottom valve closes,
and the column of water representing the entire lake water column at
that point is held within the sludge judge.
The sludge judge was applied at the 6 points shown (Dosing) in the
lake section photo above, using the gps points noted for consistency
of measurement throughout the trial.
An initial sampling was performed on June 1, 2015 at the six points
shown. Results were as follows:
Initial Sludge Depth in 3 Acre Trial Section – June 1, 2015
IniGalSludgeDepthandTotalWaterColumnDepth
7
Depth(Feet)
6
5
4
3
2
1
0
A
B
C
D
E
F
SixSludgeJudgeandDosingPoints(GPSLocated)
SludgeDepth
TotalColumnDepth
As shown in the chart above, the initial measurements (before dosing, performed June
1, 2015 using the sludge judge technique):
Total water column depth (average) = 5.6 feet
Sludge depth (average) = 1.14 feet
Therefore, before the trial began, the average sludge depth of 1.14 feet was 20% of the
total lake depth in that area.
EcoBac Dosing Program
EcoBac was prepared off-site, and brought to the
lake once a week during July, August, and
September 2015.
The product was prepared in a 275 gallon tote (see
photo to left). Each week, 275 gallons of liquid
prepared EcoBac were brought to the lake site and
dosed as close as possible to the 6 noted dose /
sample points.
Every week, about an equal amount of product was
applied to each of the six GPS identified points.
Program Results
The results are clearly shown in the charts below, with 3 measurements at each point:
before dosing, 6 weeks into dosing, and 12 weeks into dosing. All measurements were
made using the same sludge judge technique, with the same technician, and with all
measurements overseen by lake authorities.
SludgeHeightatEachPointvsTime
1.6
1.4
SludgeHeight
1.2
1
0.8
0.6
0.4
0.2
0
1
2
3
4
5
6
EachSamplePointShown(beforeEcoBac,6weeks,and12weekstreated)
BeforeDosing
6WeeksofDosing
12WeeksofDosing
Note that the sludge height was reduced at each sample point. The reduction ranged
from 10% to 58% with an average reduction of 29% in just three months of treatment.
Particularly important is that the treatment area was not cordoned off or otherwise
separated from the rest of the lake. While the defined treatment area was 3 acres, the
product applied to this area was diluted to the rest of the lake. This means that the
treatment ration (275 gallons per 3 acres per week) should be adjusted downward
considerably when scaling up to full lake treatment. With full lake treatment, the product
is applied in the desired section without dilution, while the test site allowed product to
flow away. Based on our experience, the comparable treatment rate to achieve 30%
reduction of lake sludge in 3 months in a fully confined treatment zone would be 275
gallons per week per 10 acres. If the dosing period could be extended to 6 months, the
typical rate would be 275 gallons per week per 15 acres.
The total depth of the lake varies slightly over time depending on rain, river flow, etc.,
and at the beginning of the trial, the total water column depth average across the 6
samples points was 5.6 feet, compared to 5.8 feet at the end of the 12 week trial period
(September 29, 2015).