Organic Soils, i.e. Histosols Soils: An Introduction (Singer and Munns)

Non-agricultural Use of Soil Using Soil as a Recycler

Solid Waste

Liquid Waste

Disposal/Treatment Options 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 runoff Soils: 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

Biosolids = solids after trtmt Soils: An Introduction (Singer and Munns)

Biosolids Processing

Phosphorus (P): Crop Need vs Water Quality Soil: crop production Goal: Satisfy P need, minimize P loss Water: eutrophication greenfacts.org

Balance N:P ratio in these sources less than plant requires

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 solids Lodi (Al) Portage (Fe) WI

P Removal Method: Biological primary influent trt microorganisms “eat” dissolved P solids removed by settling for further trt Madison, WI

Biosolids Trtmt Effects lime (Ca) Fe or Al biological P Removal Method

Experimental Approaches Field Study with plant real environment Incubations no plant controlled conditions

Biosolids History Incubation Soil ID Soil Series Field Biosolids History 1APlanoNone 1BPlano15 apps 2APlanoNone 2BPlano2 apps 3BRingwood13 apps P SourceTreatment TP (%) PWEP † (%) MadisonBiological BarabooLime LodiAlum (Al) PortageIron (Fe) Manure KH 2 PO † 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 KH 2 PO 4 † bars within a soil followed by the same letter are not statistically different at p=0.05

Plano 1Plano 2Ringwood 1A1B2A2B3B P Sources (0)(15 apps)(0)(2 apps)(13 apps) PBC (kg P ha -1 ) Lime Al Fe Biological Manure KH 2 PO Effects on PBC PBC = P rate/∆STP

Predicting STP Biosolid and manure properties Soil ExtractantWEPAmOxPTPP to [Fe+Al] ratio r All Soils (n=100) ΔWEP0.58***0.36***0.22*0.46*** ΔBP10.53**ns-0.39***0.52*** ΔM30.48**ns-0.37***0.40*** *, **, *** indicate statistical significance at p=0.05, 0.01, and 0.001, respectively

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?

Green Waste Reduce Reuse Recycle

Background: P Chemistry Solubility in Soils - pH dependent Brady and Weil, 1999 Optimum P availability between pH 6-7.

Effects on WEP KH 2 PO 4