Low Maintenance Wastewater Treatment using Rock Filter and ...

Low Maintenance
Wastewater Treatment
Systems
Curtis A. Fletcher
Project Manager
and
D. M. Griffin, Jr.
Principal Investigator

Topics to be Covered
• Project History and Site Modifications
• Results to Date
• Ammonia Removal

View of Lake from Waste Treatment Plant

Boating for Pleasure

Fishing is popular both from the bank and from boats

Boating, Fishing and
Water Skiing are very Popular

Initial Flow Direction in each Cell
Effluent Discharges to Lake

Current Flow

View of Waste Treatment Plant from Closest Picnic Pavilion (150 Feet)
View of Lake in the Background

Inlet Manifold and Distribution Ports

“Highly” Technical Sampler

Adjustable Effluent Pipe

Cell 2 With Mature Plants
(Lab Trailer in Background)

Cell 2 After Harvesting Plants

Plant Root Mass Wrapped Around Sample Port

Plant Root Mass & Sample Port

In-Place Skirpus Root System

Plant Root Mass (Sample Port Cap)

Cell 3 after Transferring Rock to Cell 4

Inmate Crew who Moved Rock

Cell 3 Partially Completed

Media Installation
Inmates Lifting Synthetic Media Blocks

2’ x 2’ x 4’ blocks
Synthetic Media
(Kompakt Tubular Block Media)

Cell 3 Installation Complete
Media Covered with Landscape Cloth

Cell 4 After Placing Rock From Cell 3
(Note Sample/Observation Ports)

Cell 4 – Rock Media & Aeration Ports
(3-5 Inch Diameter Granite Media)

Cell 4 Spray Aeration Port

Raw Wastewater Strength
(Septic Tank Influent)
1997-2004
Mean/Median
(mg/L)
Standard
Deviation
(mg/L)
Number of
Observations
BOD 5
563/491 349 156
TSS 825/505 863 157
TKN 119/116 40 133
NH 3
39/33 28 108
NO 3
2.8/1.1 3.7 129

Waste Strength at Splitter Box (Septic Tank Effluent)
Mean/Median
(mg/L)
S.D.
(mg/L)
Number of
Observations
Loading
Cell 3*
(kg/ha*day
)
BOD 5
177/177 55 116 85
TSS 73/69 30 121 35
TKN 105/103 31 92 50
NH 3
92/91 28 119 44
NO 3
1.88/0.45 2.7 128 0.9
*Daily flow assumed to be long term average of 5200 gpd, loading value based on mean
concentration

Effluent Cell 3
Mean/Median
(mg/L)
S.D.
(mg/L)
Number of
Observations
BOD 5
24.5/19.9 18.7 37
TSS 10.8/7 9.7 37
TKN 66/64 26 26
NH 3
37/36 26 35
NO 3
3.6/3.3 3.7 33

Waste Strength Effluent Cell 4
Mean/Median
(mg/L)
S.D.
(mg/L)
Number of
Observations
BOD 5
17.2/13.8 12.3 50
TSS 6/5 4.8 40
TKN 39.6/42.4 20.5 20
NH 3
17/13 16.4 22
NO 3
6.4/5.4 5.2 33

Temperature Variation at Splitter Box, Cells 3 & 4, Effluent
GS2 May 28, 2006 9:00:54 AM
25
TEMP.SB
Temp.cell.3
temp.cell.4
temp.cl.eff
Temperature (C)
20
15
10
5
12/1/2002 2/13/2003 4/28/2003 7/11/2003 9/23/2003 12/6/2003 2/18/2004 5/2/2004 7/15/2004 9/27/2004
Figure 9 Temperature Variation Over Time

Total Suspended Solids in Cells 3 & 4 over Time
TSS Concentrations Cells 3 and 4
40
TSS Concentration , mg/liter
30
20
10
cell 4
cell 3
0
8/1/2002 2/17/2003 9/6/2003 3/25/2004 10/12/2004

Biological Oxygen Demand (BOD) over Time
4
3
2
Pump Station
Splitter Box
Cell 1
Cell 2
10 3 2
BOD, mg/liter
6
5
4
3
2
10 2
6
5
4
3
2
10 1
6
5
4
3
curves are smoothing splines intended
only to show trends in the data
10 0
8/13/1996 7/14/1997 6/14/1998 5/16/1999 4/15/2000 3/17/2001 2/15/2002 1/17/2003

Average Flow in Gallons Per Day over Time
DAILY FLOW (GPM) AT GRAND PRAIRIE
30
GS2 Feb. 9, 2005 8:34:32 AM
NET DAILY FLOW (GPM)
20
10
LOESS REGRESSION FIT
1 DEGREE
0
7/1/1997 5/17/1999 4/1/2001 2/15/2003 12/31/2004

Commercial Package Plant

Summary of Significant Operation Events
• Hurricane Evacuation: This facility becomes a massive parking lot
during hurricane evacuation, yet the waste treatment plant has not n
been out of compliance because of the increased flow.
• Storm Water Runoff: Flow rates increase to as much as 50 gallons
per minute during thunder storms without causing any treatment
problems.
• Local Events: Neither visits by groups of tour buses nor horse riding r
events where the horse trailers have been washed out into the RV
dump have caused any problems. BOD and TSS have increased, but
not enough to cause any compliance or operation problems.
• The water well washed out during one of the hurricanes and the
increased flow was detected by the system flow measuring
equipment. This could have caused serious damage if the increased
flow with the associated increase in sand content in the flow stream
had not been detected. The rest area could have been shut down
for several weeks

Recommendations and Conclusions
• Robust System: Successfully treats strong influent stream without
serious problems.
• Ease of Operation: Only exceeded the permit once in ten years
because of a treatment plant problem; i.e., week of subfreezing
temperatures. Effluent increased to 54 mg/L BOD while the permit
limit is 45 mg/L. DOTD was not cited because the effluent average
stayed well within the permit limits.
• Continued Operation: Since research ended in 2004; the treatment
system continues to meet the permit without a trained operator.
Rest area attendants add chlorine tablets and call for assistance e if
lift stations need maintenance.
• Effluent has not been above 20 mg/L in BOD or TSS.
• Rock and synthetic media filters have proven very successful in
treating strong influent volumes of 10,000 gallons per cell (30’ x
150’) ) with minimal maintenance.
• This type of cell would be ideal for a pilot project since each cell is
an independent system. Cells can be added to increase volume as
desired. Individual cells can be shut down for maintenance and
inspection without affecting operations.
• A pilot project could be built at very little cost since a plastic lining
can be placed in a hole in the ground and then filled with selected
media.

Son-in
in-Law and Pepper after listening to Presentation