Natural Resources Extension Program
Step 6. Liquid waste nutrient
This worksheet estimate the nutrients in containment ponds.
Example Information:
Estimated nutrients in containment pond, which consists of 80% supernatant and 20% sludge and based on an annual precipitation of 13 inches. It is estimated only 30% of the 13 inches has the potential to runoff, which creates 3.9 ac-in (32.5% Ac-Ft) or 105,900 gallons of runoff.
Nutrient content Supernatant Sludge
(NRCS Ag Waste Management Handbook, Table 4-10)
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Nutrient
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N = |
1.67 lb/1000 gal |
51.66 lb/1000 gal
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NH4-N =
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1.50 lb/1000 gal
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P =
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17.5 lb/1000 gal
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K =
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7.5 lb/1000 gal
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14.17 lb/1000 gal
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Nitrogen in Supernatant
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1.
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Calculate amount of organic N in manure per 1000 gal lb total N – (lb ammonium N + lb nitrate N) = lb organic N/1000 gal |
1.67 – (1.5 + 0) = 0.17 lb/1000 gal |
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2.
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Calculate amount of organic N in manure available: lb organic N/1000 gal. x mineralization factor* = available organic N/ton |
0.17 x 0.3 (mineralization factor) = 0.05 lb N
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3.
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Calculate amount of plant-available N in manure: available organic N + ammonium N + nitrate N = lb plant available N/1000 gal |
0.05 lb + 1.50 lb + 0 = 1.55 lb available N/1000 gal
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4.
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Calculate amount of plant-available N in runoff: lb plant available N/1000 gal x runoff = lb plant available N/1000 gal of runoff |
1.55 lb x 105.9 (1000 gal) = 164 lb N
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5.
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Adjust for volatilization: Volatilization from application = 1/3 loss |
164 lb x .66 = 108.4 lb N
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6.
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In this example 80% is supernatant
Available Nitrogen in supernatant |
80% supernatant x 108.4 = 86.6 lb available N
50 lb/ac is applied to perennial grass that will produce 2 ton/ac
Therefore 1.7 ac needed to apply supernatant from holding pond. |
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Available Phosphorus in Supernatant - No available phosphorus in supernatant
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1.
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Calculate amount of K in runoff: lb plant available K/1000 gal x runoff = lb plant available K/1000 gal of runoff |
7.5 lb x 105.9 (1000 gal) = 794.25 lb K |
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2.
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In this example 80% is supernatant.
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794.25 x 80% = 635.4 lb K
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3.
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Convert K to K2O (divide by 0.83).
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635.4 lb divided by 0.83 = 765.5 lb K2O
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Sludge
In this example 20% is sludge (figures added to land application)
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1.
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Calculate amount of organic N in manure available: lb organic N/1000 gal. x mineralization factor* = available organic N/ton |
51.66 lb N x 0.3 (mineralization factor) = 15.5 lb N |
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2.
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Calculate amount of plant-available N in runoff: lb plant available N/1000 gal x runoff = lb plant available N/1000 gal of runoff |
15.5 lb N x 105,900 gal = 1641 lb N
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3.
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In this example 20% is sludge
Available N in sludge. |
1641 lb x 20% = 328 lb N
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1.
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Calculate amount of P in runoff: lb P/1000 gal x runoff (1000 gal) = P/1000 gal of runoff |
17.50 lb x 105.9 (1000 gal) = 1853 lb. P |
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2.
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In this example, the nutrients in the containment pond consist of 80% supernatant
and 20% sludge. Therefore, multiply by 20% to determine the available P from sludge.
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1853 x 20% = 370.7 lb P
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3.
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Convert P to P2O5 (divide by 0.44)
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370.7 lb P divided by 0.44 = 842 lb P2O5
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Calculate amount of K in runoff: lb P/1000 gal x runoff (1000 gal) = P/1000 gal of runoff |
14.17 lb x 105.9 (1000 gal) = 1500.6 lb K |
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| 2. | In this example, the nutrients in the containment pond consist of 80% supernatant and 20% sludge. Therefore, multiply by 20% to determine the available K from sludge. | 1500.6 x 20% = 300 lb K |
| 3. | Convert K to K2O (divide by 0.83). | 300 lb divided by 0.83 = 362 lb K2O3 |