organic soils, i.e. histosols soils: an introduction (singer and munns)
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Disposal/Treatment Options
http://ga.water.usgs.gov/edu/wuww.html
Soils: An Introduction (Singer and Munns)
Two options:On-site: Septic System
Off-site: Sewage Trt Plants
Waste Water Treatment Plants(WWTP)
Combined OR Separate sewage
from runoffSoils: An Introduction (Singer and Munns)
WWTP Goals:
Clean water (effluent) to return to streams remove excess
nutrients minimize pathogens appropriate
temperature
Sanitary solids disposal landfill incinerate land application
Phosphorus (P): Crop Need vs Water
Quality
Soil:crop production
Goal: Satisfy P need, minimize P loss
Water:eutrophication
greenfacts.org
Effects of Biosolids Treatment
Biosolids concentrated with P disposal=land
application
Do biosolids differ in P availability as compared to manure or fertilizer?
P Removal Method: Lime
solids pumped to this tank
addition of lime raise pH
reduce pathogens precipitate P as Ca-P
(very insoluble)Baraboo, WI
P Removal Method: Fe or Al
add at influent entry Fe
precipitate Fe-P can become soluble
in reducing conditions
Al precipitate Al-P too much Al can
cause toxicity in soil
separate for solidsLodi (Al)Portage (Fe) WI
P Removal Method: Biological
primary influent trt microorganisms “eat”
dissolved P solids removed by
settling for further trtMadison, WI
Experimental Approaches
Field Study with plant real environment
Incubations no plant controlled conditions
Biosolids History Incubation
Soil IDSoil
Series
Field Biosolids History
1A Plano None
1B Plano 15 apps
2A Plano None
2B Plano 2 apps
3BRingwood
13 apps
P Source
Treatment
TP(%)
PWEP†
(%)
Madison
Biological
4.45 11.3
Baraboo
Lime 1.05 0.1
LodiAlum (Al)
3.67 0.3
Portage Iron (Fe) 3.63 1.2
Manure - 0.67 33.8
KH2PO4 - 22.8 100
† PWEP=percent of TP that is water extractable
Soil Classification
Plano Fine-silty, mixed, superactive, mesic Typic Argiudolls
Ringwood Fine-loamy, mixed, superactive, mesic Typic Argiudolls
Both soils are typical of MMSD land-application program
Effects on Bray P1
-10
0
10
20
30
40
50
60
1A=0 apps 1B=15 apps
Soil
Bra
y P
1 ch
ang
e (m
g P
kg-1
)
Lime Al Fe Biological Manure KH2PO4
a
b
bc
b c
d
a
bb
c c
d
KH2PO
4
† bars within a soil followed by the same letter are not statistically different at p=0.05
Plano 1 Plano 2 Ringwood
1A 1B 2A 2B 3B
P Sources(0) (15
apps)(0) (2
apps)(13 apps)
--------------------------PBC (kg P ha-
1)--------------------------
Lime 8.4 10.5 6.6 8.5 8.3
Al 19.9 -104.7 23.8 45.4 -222.9
Fe 9.2 12.6 10.6 17.4 16.7
Biological 7.0 5.8 8.3 8.2 7.2
Manure 7.3 5.2 7.3 7.9 6.2
KH2PO4 4.2 2.7 4.5 3.7 3.7
Effects on PBCPBC = P rate/∆STP
ALL SOILS; r=0.53
-10
-5
0
5
10
15
20
25
30
0 1 2 3 4 5 6
Water Extractable P in Biosolids (g kg-1)
Change in B
P1 (
mg k
g-1)
Predicting STP
Biosolid and manure properties
Soil Extractant
WEP AmOxP TPP to [Fe+Al]
ratio
---------------------------r---------------------------
All Soils (n=100)
ΔWEP 0.58*** 0.36*** 0.22* 0.46***
ΔBP1 0.53** ns -0.39*** 0.52***
ΔM3 0.48** ns -0.37*** 0.40***
*, **, *** indicate statistical significance at p=0.05, 0.01, and 0.001, respectively
-10
10
30
50
70
90
110
-100 -50 0 50 100 150 200
P Rate
= Total P Added - P Removed (kg P ha-1)
Ch
an
ge
in
Bra
y P
1 (
mg
P k
g-1) Biological: PBC=4
Lime: PBC=4
Al: PBC=6
Fe: PBC=8
Arlington Field Experiment
Effects on Bray P1
Conclusions
P source treatment greatly influences P availability: lime and biologically treated biosolids change BP1
similar to a typical dairy manure Fe and Al treated biosolids have significantly
greater PBC P fertilizer has the smallest PBC
Field results follow same trends as Incubations
WEP of biosolids could be used to predict PBC
Implications
Is there a “best” method for P removal?
Does P removal method have implications for the functionality of biosolids for other purposes (besides keeping P from leaving in runoff)?
What do WWTP operates need to take into account when deciding on a P removal process?
How is soil being used as a recycler?
Background:P Chemistry
Solubility in Soils - pH dependent
Brady and Weil, 1999
Optimum P availability between pH 6-7.
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