Manual for Designing Surface Application of OSSF W/W Effluent
Manual for Designing Surface Application of OSSF W/W Effluent
Manual for Designing Surface Application of OSSF W/W Effluent
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<strong>Manual</strong> <strong>for</strong> <strong>Designing</strong> <strong>Surface</strong><br />
<strong>Application</strong> <strong>of</strong> <strong>OSSF</strong> W/W <strong>Effluent</strong><br />
by<br />
Clif<strong>for</strong>d B. Fedler<br />
Texas Tech University<br />
March 5, 2008<br />
clif<strong>for</strong>d.fedler@ttu.edu
<strong>Surface</strong> treatment <strong>of</strong> wastewater is<br />
accomplished through the controlled<br />
application i onto a land surface such that a<br />
designed degree <strong>of</strong> treatment through natural<br />
physical, chemical, and dbiological i lprocesses<br />
occurs in the plant-soil-water matrix.
Basic System<br />
Sprayfield<br />
Wastewater<br />
Aerobic<br />
Treatment or<br />
Septic Tank<br />
Plant root zone
<strong>Surface</strong> <strong>Application</strong> System<br />
Wastewater Applied<br />
Grass<br />
Crop Root Zone<br />
Leachate Water
<strong>Surface</strong> <strong>Application</strong> System<br />
Pi Principle il Design Parameters:<br />
Evapotranspiration/Evaporation<br />
Deep Percolation/Leaching<br />
Soil Properties<br />
water intake rate<br />
Crop Selection<br />
nutrient uptake/removal<br />
active growth period<br />
Wastewater <strong>Application</strong><br />
drip<br />
sprinkler<br />
Run<strong>of</strong>f Control<br />
Storage
Design Components<br />
Water, Nitrogen & Salt Balance<br />
Wastewater ppt ET<br />
No run<strong>of</strong>f allowed<br />
Grass<br />
Crop Root Zone<br />
Leaching
What affects the Water Balance?<br />
Wastewater application rate<br />
Evapotranspiration p (crop)<br />
Precipitation<br />
Soil water storage<br />
Leaching<br />
Run<strong>of</strong>f
The Soil-Water System<br />
Saturation<br />
Field<br />
Capacity<br />
Permanent<br />
Wilting Point<br />
Available<br />
Water<br />
Unavailable<br />
Water<br />
Gravitational<br />
Water<br />
Capillary<br />
Water<br />
Hygroscopic<br />
Water
Saturated<br />
Conditions<br />
Draining<br />
Conditions<br />
Field<br />
Capacity
Field<br />
Capacity<br />
Available<br />
Moisture<br />
Wilting<br />
Point
Field<br />
Capacity<br />
Readily<br />
Available<br />
Moisture<br />
Wilting<br />
Point
Main Design Components Required<br />
‣ Sprinkler Spacing<br />
‣ Operating Pressure<br />
‣ Selection <strong>of</strong> Sprinkler Heads<br />
‣ Pressure Losses in Main Pipeline<br />
‣ Risers<br />
‣ <strong>Application</strong> Rate<br />
‣ Soil Infiltration Rate<br />
‣ Time <strong>of</strong> <strong>Application</strong>
Typical sprinkler patterns
UCC<br />
UCC is Christiansen’s coefficient <strong>of</strong><br />
uni<strong>for</strong>mity. It is used to quantify<br />
the uni<strong>for</strong>mity <strong>of</strong> water application<br />
by sprinklers.
Water <strong>Application</strong> Efficiency<br />
Water application uni<strong>for</strong>mity under<br />
irrigation depends on uni<strong>for</strong>mity <strong>of</strong> the<br />
sprinklers and not on soil properties, so<br />
long as the application rate does not exceed<br />
the intake rate <strong>of</strong> the soil.
Water <strong>Application</strong> Efficiency<br />
E a = 100(d r /d a )<br />
d r = Average depth <strong>of</strong> irrigation water<br />
stored in the root zone.<br />
d a = Average depth or net application<br />
rate.
Irrigation Efficiency<br />
i<br />
E s = Avg Depth <strong>of</strong> Irr. Water Beneficially Used<br />
Average Depth Applied
Ea = 100% Es = 50% UCC = 75%
Ea = 90% Es = 90% UCC = 85%
Ea = 60% Es = 100% UCC = 95%
Irrigation Efficiency testing setup
Use the Square Block Design<br />
With head-to-head overlap<br />
vs.
Single Sprinkler Pattern<br />
h <strong>of</strong> Wa ater<br />
R elative e Dept<br />
30<br />
25<br />
20<br />
15<br />
10<br />
5<br />
0<br />
-40 -32 -24 -16 -8 0 8 16 24 32 40<br />
Distance from Sprinkler Head, ft
Overlapping Sprinkler Pattern<br />
35<br />
Depth o f Water<br />
Relative<br />
30<br />
25<br />
20<br />
15<br />
10<br />
5<br />
0<br />
-40 -32 -24 -16 -8 0 8 16 24 32 40<br />
Distance from Sprinkler Head, ft
Impact Sprinkler Type:<br />
Burgess 503, UCC=51%<br />
Single Sprinkler Distribution, ib i No Overlap<br />
160<br />
140<br />
120<br />
100<br />
Volume (mL)<br />
80<br />
60<br />
40<br />
20<br />
0<br />
S1<br />
S4<br />
S7<br />
Can Spacing - 4<br />
ft.<br />
1 2 3 4 5 6 7 8 9<br />
Can Spacing - 4 ft.
Impact Sprinkler Type: Burgess 503<br />
UCC: 84.68, 16x16 spacing<br />
Multiple Sprinkler Distribution, Head-to-Head<br />
Spacing<br />
300<br />
250<br />
200<br />
Volume (mL)<br />
150<br />
100<br />
50<br />
0<br />
S1<br />
S4<br />
S7<br />
Can Spacing - 4<br />
ft.<br />
1 2 3 4 5 6 7 8<br />
Can Spacing - 4 ft.
UCC <strong>of</strong> Sprinklers-<br />
Effect <strong>of</strong> Pressure<br />
Model<br />
Toro s700 N3<br />
Toro s700<br />
N4.5<br />
Toro s700 N3<br />
Toro s700<br />
N4.5<br />
Toro s700 N3<br />
Toro s700<br />
N4.5<br />
Type<br />
Impact<br />
Impact<br />
Impact<br />
Impact<br />
Impact<br />
Impact<br />
Pressure<br />
UCC (%)<br />
(psi)<br />
30 75.36<br />
30 50.90<br />
40 86.6767<br />
40 74.22<br />
50 90.40<br />
50 79.96
As = 1-Ys-a<br />
b<br />
minsion nless dep pth, Y=y y/y<br />
1.1<br />
1.0<br />
0.9<br />
Y min<br />
Y max<br />
b<br />
Di<br />
0<br />
Deficit<br />
Surplus a<br />
05 0.5<br />
Fraction <strong>of</strong> Area, X
Distribution <strong>of</strong> Nitrogen<br />
Nitro ogen, kg g/ha<br />
400.0<br />
300.00<br />
200.0<br />
100.00<br />
0.0<br />
0.<br />
0.<br />
0.<br />
0.<br />
0<br />
.2<br />
.4<br />
.6<br />
.8<br />
1<br />
Fraction <strong>of</strong> Area
Where does the nitrogen go?<br />
In a surface application system,<br />
nitrogen is largely consumed by crop<br />
Some nitrogen percolates below the<br />
root zone<br />
Some nitrogen is lost by<br />
denitrification
Denitrification<br />
2NO 2NO 2NO N O N<br />
2NO 3- ==> 2NO 2- ==> 2NO ==> N 2 O ==> N 2<br />
+5 +3 +2 +1 0
Denitrification ifi ti is dependent d on:<br />
‣ Moisture Content<br />
t<br />
‣ Temperature<br />
‣ Nitrogen concentration<br />
ti<br />
‣ Carbon concentration
Examples <strong>of</strong> Nitrogen Consumption<br />
Crops<br />
Pioneer Succession Vegetation<br />
Mixed Hardwoods<br />
Alfalfa<br />
Coastal Bermudagrass<br />
Kentucky Bluegrass<br />
Pasture<br />
Corn<br />
Annual Nitrogen Uptake (lb/ac)<br />
223<br />
178<br />
340<br />
479<br />
209<br />
68<br />
167
What makes a crop selectable?<br />
Bermuda Grass<br />
Has medium consumptive water use<br />
Hashighnitrogenrequirements<br />
requirements<br />
Does not fix nitrogen<br />
Has high tolerance <strong>for</strong> salts<br />
Cannot be maintained wet <strong>for</strong> long periods<br />
Can grow 12 months/year (some areas)<br />
Produces a saleable product
Accumulation <strong>of</strong> Salts<br />
• Upward movement <strong>of</strong> water<br />
– high evaporative demand in arid and semi arid<br />
regions<br />
– insufficient rainfall to leach salts<br />
• Poor drainage<br />
– salts must be leached from the root zone to<br />
prevent their accumulation
Salinity and Plant Growth<br />
• Salt stress increases the amount <strong>of</strong><br />
energy that a plant must spend to take<br />
water from the soil<br />
• This energy is not available <strong>for</strong> normal<br />
plant growth<br />
• This results in an overall reduction in<br />
plant growth
Wastewater<br />
Water<br />
Salt<br />
Nitrogen<br />
Water<br />
Nitrogen<br />
Water Salt Nitrogen<br />
Crop Root Zone<br />
Water<br />
Salt<br />
Nitrogen
Design Recommendations<br />
• The discharge rate between the sprinkler<br />
with the lowest rate and the sprinkler<br />
with the highest rate <strong>for</strong> a set should be<br />
less than 10%.<br />
• Design pressure should be mid-range <strong>of</strong><br />
specified pressure.
Design Recommendations<br />
• Sprinklers should be spaced head-tohead<br />
• The pressure difference between the<br />
sprinkler with the highest pressure and<br />
the sprinkler with the lowest pressure in<br />
a set should be less than 20%.
Design Recommendations<br />
• The layout in a block pattern <strong>for</strong> headto-head<br />
overlap or a seasonal uni<strong>for</strong>mity<br />
coefficient > 80%.<br />
• Gear head type sprinklers should be<br />
used and not spray head type sprinklers.
Design Recommendations<br />
• Risers <strong>of</strong> 6 inches should be used when<br />
the discharge rate is < 12 gpm and 12<br />
inches <strong>for</strong> discharge rates between 12<br />
and 26 gpm.<br />
• The application rate # the base water<br />
intake rate <strong>of</strong> the soil plus 0.1 inches <strong>for</strong><br />
interception.<br />
ti
Design Recommendations<br />
• The base soil infiltration rate should be<br />
set equal to the saturated hydraulic<br />
conductivity <strong>of</strong> the top 18 inches <strong>of</strong> soil.<br />
• A check-<strong>of</strong>f list <strong>of</strong> design considerations<br />
g<br />
should be developed and used on all<br />
new and renovated systems.
Design Recommendations<br />
• All designs should consider both a water<br />
• All designs should consider both a water<br />
balance and a nutrient balance.
<strong>OSSF</strong> <strong>Surface</strong> <strong>Application</strong> System<br />
Pi Principle il Design Parameters:<br />
Evapotranspiration/Evaporation<br />
Deep Percolation/Leaching<br />
Soil Properties<br />
water intake rate<br />
soil water storage<br />
Crop Selection<br />
nutrient uptake/removal<br />
active growth period<br />
Wastewater <strong>Application</strong><br />
Run<strong>of</strong>f Controlo<br />
Effect <strong>of</strong> PPCP’s and bacteria movement
Thank you <strong>for</strong> your attention<br />
One World
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