Solutions and Swine Manure Slurry Using Soybean Peroxidase and Peroxides

Transcription

1 Reduction of Odorous VOC in Phenolic Solutions and Swine Manure Slurry Using Soybean Peroxidase and Peroxides David Parker, Supervisory Research Agricultural Engineer USDA-ARS, Clay Center, Nebraska Lingshuang Cai Iowa State University, Ames, Iowa Mark Olsen Midwestern University, Glendale, Arizona For presentation at the 242 nd American Chemical Society National Meeting August 28-September 1, 211

2 Background: There are 2+ chemical compounds emitted from manure. The most persistent compounds in manure, and those most responsible for odor at a distance, are the phenolics, indolics, and sulfides. 4-methylphenol yp (i.e. p-cresol) ) is the most important. phenol 127 µg/m ppb 4-methylphenol 2.6 µg/m 3.6 ppb indole 1.9 µg/m 3.4 ppb skatole 1.6 µg/m 3.3 ppb dimethyl trisulfide dimethyl disulfide 12 µg/m 3 2. µg/m ppb.4 ppb Our strategy is to target these individual key odorants, thereby reducing odor impacts at downwind locations.

3 Odor Activity Value Analysis for Swine Manure from Pull-Plug System 1 9 Relative Percentage of Integrated OAV Indole+Phenol+DMDS+DMTS 4-Ethylphenol Sum 8 VFAs Skatole 4-Methylphenol Week 4-Methylphenol accounted for 79.5% of the overall OAV Skatole=12.3%, 4-ethylphenol=1.2%

4 In the presence of peroxidase enzyme (horseradish peroxidase or soybean peroxidase) and an oxidizing agent (either hydrogen peroxide or calcium peroxide), phenolic compounds are polymerized to form relatively insoluble and nonvolatile biphenol groups. Phenol + HRP + H₂O₂ = 4,4 -Biphenol 2,2 -Biphenol 4-phenoxyphenol 4-(4-phenoxyphenoxy)phenol

5 Objectives: Phase 1 Evaluate and optimize commercially-available plant-derived peroxidase enzyme products for reducing odors in swine manure (today s presentation) Phase 2 Optimize the effectiveness of genetically modified yeast, expressing the horseradish peroxidase enzyme, for abatement of odorous compounds in swine lagoon wastewater (ongoing research)

6 Methods: SBP and H 2 O 2 /CaO 2 added to 1) standard solution of phenol/4-methylphenol 2) swine manure Air emissions measured in a small wind tunnel, using sweep air flow rate=1 LPM, 15 mm petri dish VOC l d i b t VOCs sampled in sorbent tubes, quantified by GC/MS with TD system

7 Methods: Soybean Peroxidase, industrial-strength commercial product Ground soybean hulls.8 U/mg (compare to refined HRP 255 U/mg) H 2 O 2 3%, liquid CaO 2 2%, powder Swine manure fresh manure, collected from U.S. Meat Animal Research Center 12 Laboratory Experiments Conducted 5 Laboratory Experiments Reported

8 Methods: Exp. 1: Optimize SBP in std solution Std. solution of 1mM phenol and 1mM 4-methylphenol 2.65 mm H 2 O 2 (2 hr) SBP, 1, 5, 1, 25, 5, 1 mg/l Exp. 2: Optimize H 2 O 2 in std solution Std. solution of 1mM phenol and 1mM 4-methylphenol 5 mg/l SBP (2 hr).4,1.3, 2.6, 5.3, 1.6, 44.1 mm H 2 O 2 Exp. 3: Optimize SBP in swine slurry 14.6 mm H 2O 2 (24 hr) SBP 5, 25, 5, 75, 1 mg/l Exp. 4: Optimize H 2 O 2 and CaO 2 in swine slurry 5 mg/l SBP (24 hr), 14.6, 38 mm H 2 O 2 ;, , , , mm CaO 2 Exp. 5: 1 mg/l SBP 14.6 mm H 2 O 2 ; 22.1 mm CaO 2 (2 hr, 24 hr, 48 hr; 3 Reps of Each TRT)

9 Results: Exp. 1 Optimize SBP in std solution Std. solution of 1mM phenol and 1mM 4-methylphenol 2.6 mm H 2 O 2 (2 hr) SBP, 1, 5, 1, 25, 5, 1 mg/l 25 2 Std. Solution 1mM phenol and 1mM 4 methylphenol 2 hr samples Flu ux (μg m 2 min 1 ) 15 1 phenol 4 methylphenol Soybean PeroxidaseAdded (mg/l) Optimal SBP for 4-methylphenol reduction = 1 mg/l; for phenol, 5 mg/l

10 Results: Exp Optimize H 2 O 2 in std solution Std. solution of 1mM phenol and 1mM 4-methylphenol 5 mg/l SBP (2 hr),.4,1.3, 2.6, 5.3, 1.6, 44.1 mm H 2 O 2 Std. Soln. 1 mm phenol and 1 mm 4 methylphenol Flux (μg m -2 min -1 ) phenol 4 methylphenol H 2 O 2 (mm) Optimal H2O2 for 4-methylphenol reduction = 1.3 to 2.6 mm

11 Results: Exp. 3 Optimize SBP in swine slurry 14.6 mm H 2 O 2 (24 hr) SBP, 5, 25, 5, 75, 1 mg/l in 1 ) Flux (μ μg m 2 m Effects of SBP concentrations in swine slurry after 24 hr treatment phenol 4 methyl phenol indole skatole DMDS DMTS Soybean peroxidase added (mg/l) Optimal SBP for swine manure = 5 mg/l (5 g/l)

12 Results: Exp. 4 6 Optimize H 2 O 2 and CaO 2 in swine slurry 5 mg/l SBP (24 hr), 14.6, 38 mm H 2 O 2 ;, 14.6, 22.1, 38., 76. mm CaO 2 Effects of H 2 O 2 and CaO 2 on odorous compounds in swine slurry (after 24 hr treatment) in -1 ) Flux (μg m -2 m phenol 4 methylphenol indole skatole DMDS DMTS Control 14.6 mm H2O2 38. mm H2O mm CaO mm CaO2 H 2 O 2 or CaO 2 (mm) 38. mm CaO2 Optimal H 2 O 2 =14.6 to 38. mm; CaO 2 =22.1 mm 76. mm CaO2

13 Results: Exp. 5 5 mg/l SBP 14.6 mm H 2 O 2 ; 22.1 mm CaO 2 (2 hr, 24 hr, 48 hr; 3 Reps of Each TRT) Flux (μg m -2 min -1 ) Phenol 2 hr 24 hr 48 hr Flux (μg m -2 min -1 ) Methylphenol 2 hr 24 hr 48 hr Control 14.6 mm H2O mm CaO2 Control 14.6 mm H2O mm CaO2 Flux (μg m -2 min -1 ) Indole 6 2 hr 24 hr 48 hr Flux (μ μg m -2 min -1 ) Skatole 2 hr 24 hr 48 hr. Control 14.6 mm H2O mm CaO2 Control 14.6 mm H2O mm CaO2 5 mg/l and 22.1 mm CaO2 very effective in controlling 4-methylphenol Effectiveness increased over time from 2 hr to 48 hr

14 Results: Exp. 5 5 mg/l SBP 14.6 mm H 2 O 2 ; 22.1 mm CaO 2 (2 hr, 24 hr, 48 hr; 3 Reps of Each TRT) min -1 ) Flux (μg m DMDS 2 hr 24 hr 48 hr min -1 ) Flux (μg m DMTS 2 hr 24 hr 48 hr Control 14.6 mm H2O mm CaO2. Control 14.6 mm H2O mm CaO2 Flux (μg m -2 min -1 ) 1,2 1, Total VFA 2 hr 24 hr 48 hr H2O2 and CaO2 reduced DMDS and DMTS initially, but more importantly kept them from being produced after 48 hrs CaO2 was more effective than H2O2 for VFAs Control 14.6 mm H2O mm CaO2

15 CONCLUSIONS: The following conclusions were drawn from this research: 1. Commercially-available SBP was effective at reducing odor-causing compounds from swine manure, especially 4-methylphenol. 2. Both peroxides reduced DMDS and DMTS. When used with SBP, CaO2 was more effective than H2O2 at reducing phenolics. H2O2 increased VFA emissions. 3. Even when SBP is purchased in bulk ($6.6/kg), the treatment cost ($.33 per liter of manure treated) is not economical. In future research we will focus on improving economics by: 1) Evaluating topical application only, and 2) Using genetically modified yeast, expressing the HRP enzyme