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An ozonation study was conducted for inactivating Fusarium oxysporum, which causes Fusarium wilt, the most serious soil-borne disease in hydroponic cultivation systems. Samples of conidial suspensi...

Control of gaseous emissions from livestock operations is needed to ensure compliance with environmental regulations and sustainability of the industry. The focus of this research was to mitigate livestock odor emissions with UV light. Effects of the UV dose, wavelength, TiO2 catalyst, air temperature, and relative humidity were tested at lab scale on a synthetic mixture of nine odorous volatile organic compounds (VOCs) and real poultry manure offgas. Results show that it was feasible to control odorous VOCs with both photolysis and photocatalysis (synthetic VOCs mixture) and with photocatalysis (manure offgas). The treatment effectiveness R (defined as % conversion), was proportional to the light intensity for synthetic VOCs mixtures and followed an order of UV185+254 + TiO2 &gt, UV254 + TiO2 &gt, UV185+254, no catalyst &gt, UV254, no catalyst. VOC conversion R &gt, 80% was achieved when light energy was &gt, ~60 J L&minus, 1. The use of deep UV (UV185+254) improved the R, particularly when photolysis was the primary treatment. Odor removal up to ~80% was also observed for a synthetic VOCs mixture, and actual poultry manure offgas. Scale-up studies are warranted.

Nearly 55,000 outbreaks of animal disease were reported to the World Animal Health Information Database between 2005 and 2016. To suppress the spread of disease, large numbers of animal mortalities often must be disposed of quickly and are frequently buried on the farm where they were raised. While this method of emergency disposal is fast and relatively inexpensive, it also can have undesirable and lasting impacts (slow decay, concerns about groundwater contamination, pathogens re-emergence, and odor). Following the 2010 foot-and-mouth disease outbreak, the Republic of Korea's National Institute of Animal Science funded research on selected burial alternatives or modifications believed to have potential to reduce undesirable impacts of burial. One such modification involves the injection of air into the liquid degradation products from the 60–70% water from decomposing carcasses in lined burial trenches. Prior to prototype development in the field, a laboratory-scale study of aerated decomposition (AeD) of poultry carcasses was conducted to quantify improvements in time of carcass decomposition, reduction of potential groundwater pollutants in the liquid products of decomposition (since trench liners may ultimately leak), and reduction of odorous VOCs emitted during decomposition. Headspace gases also were monitored to determine the potential for using gaseous biomarkers in the aerated burial trench exhaust stream to monitor completion of the decomposition. Results of the lab-scale experiments show that the mass of chicken carcasses was reduced by 95.0 ± 0.9% within 3 months at mesophilic temperatures (vs. negligible reduction via mesophilic anaerobic digestion typical of trench burial) with concomitant reduction of biochemical oxygen demand (BOD; 99%), volatile suspended solids (VSS; 99%), total suspended solids (TSS; 99%), and total ammonia nitrogen (TAN; 98%) in the liquid digestate. At week #7 BOD and TSS in digestate met the U.S. EPA standards for treated wastewater discharge to surface water. Salmonella and Staphylococcus were inactivated by the AeD process after week #1 and #3, respectively. Five gaseous biomarkers: pyrimidine; p-cresol; phenol; dimethyl disulfide; and dimethyl trisulfide; were identified and correlated with digestate quality. Phenol was the best predictor of TAN (R = 0.96), BOD (R = 0.92), and dissolved oxygen (DO) (R = −0.91). Phenol was also the best predictor populations of Salmonella (R = 0.95) and aerobes (R = 0.88). P-cresol was the best predictor for anaerobes (R = 0.88). The off-gas from AeD will require biofiltration or other odor control measures for a much shorter time than anaerobic decomposition. The lab-scale studies indicate that AeD burial has the potential to make burial a faster, safer, and more environmentally friendly method for emergency disposal and treatment of infectious animal carcasses and that this method should be further developed via prototype-scale field studies.

A passive sampling method, using retracted solid-phase microextraction (SPME) - gas chromatography-mass spectrometry and time-weighted averaging, was developed and validated for tracking marker volatile organic compounds (VOCs) emitted during aerobic digestion of biohazardous animal tissue. The retracted SPME configuration protects the fragile fiber from buffeting by the process gas stream, and it requires less equipment and is potentially more biosecure than conventional active sampling methods. VOC concentrations predicted via a model based on Fick's first law of diffusion were within 6.6-12.3% of experimentally controlled values after accounting for VOC adsorption to the SPME fiber housing. Method detection limits for five marker VOCs ranged from 0.70 to 8.44ppbv and were statistically equivalent (p>0.05) to those for active sorbent-tube-based sampling. The sampling time of 30min and fiber retraction of 5mm were found to be optimal for the tissue digestion process.

An innovative bioprocess utilizing thin stillage from a dry-grind corn ethanol plant was used to produce a useful filamentous fungus (Rhizopus microsporus var. oligosporus) in a pilot-scale bioreactor. The fungal process can improve the economics of corn ethanol production by producing an excellent food supplement for livestock or serving as a feedstock material for producing chitin, chitosan, and glucosamine. However, in order to be economically viable, effective and low-cost mechanical dewatering of the fungal biomass grown in thin stillage is required. In this study, dewatering tests were performed on fungal biomass using gravity and centrifugal sedimentation, gravity screening, a belt filter, a filter press, and centrifuge filtration in order to determine the most effective dewatering methods for this application. Utilizing a gravity-fed concave screen followed by a centrifuge filter proved to be the most effective dewatering approach and increased the screenable solids (i.e., larger than 20 mesh) content of the fungal biomass from the bioreactor from 1% to 30%. Achieving a solids content greater than 30% with mechanical dewatering is unlikely because of theoretical limits due to intracellular water. Nonetheless, this degree of dewatering greatly reduces thermal drying costs necessary to obtain a final product with a moisture content of 10%.

Groundwater contamination with chlorinated hydrocarbons has become a widespread problem that threatens water quality and human health. Permeable reactive barriers (PRBs), which employ zerovalent iron, are effective for remediation; however, a need exists to reduce the economic and environmental costs associated with constructing PRBs. We present a method to produce zerovalent iron supported on macroporous carbon using only lignin and magnetite. Biochar-ZVI (BC-ZVI) produced by this method exhibits a broad pore size distribution with micrometer sized ZVI phases dispersed throughout a carbon matrix. X-ray diffraction revealed that pyrolysis at 900 °C of a 50/50 lignin–magnetite mixture resulted in almost complete reduction of magnetite to ZVI and that compression molding promotes iron reduction in pyrolysis due to mixing of starting materials. High temperature pyrolysis of lignin yields some graphite in BC-ZVI due to reduction of carbonaceous gases on iron oxides. TCE was removed from water as it passed thr...

Pyrolysis of biorenewable feedstocks and iron oxides is potentially a greener and more sustainable pathway to producing zerovalent iron (ZVI) for environmental rehabilitation. The resulting biochar-zerovalent iron (BC-ZVI) also shows improved remediation kinetics of trichloroethylene over conventional ZVI. Understanding the transformations of iron to ZVI and the influence of feedstock chemistry on ZVI is critical to the production of BC-ZVI and has not been reported previously. BC-ZVI production was studied by one-step pyrolysis of cellulose, corn stover, dried distillers’ grain, red oak, and switchgrass pretreated with FeCl3. Pyrolysis at 900 °C effectively reduced Fe to ZVI with most feedstocks; however, the association of silicon (Si) and phosphorus (P) with Fe resulted in formation of fayalite and Fe phosphates and phosphides, which limited ZVI production efficiency and/or facilitated corrosion of ZVI. Dispersion of ZVI phases on biochar surfaces and association with Si facilitated oxidation of ZVI du...

Ethanol production in the United States approached 15 billion gal/year in 2015. Only about 2.5% of this was food-grade alcohol, but this represents a higher-value product than fuels or other uses. The ethanol production process includes corn milling, cooking, saccharification, fermentation, and separation by distillation. Volatile byproducts are produced during the fermentation of starch. These include other alcohols, aldehydes, ketones, fatty acids and esters. Food-grade ethanol is generally produced by wet milling, where starch and sugars are separated from the other corn components, resulting in much smaller concentrations of the impurities than are obtained from fermentation of dry-milled corn, where cyclic and heterocyclic compounds are produced from lignin in the corn hull. Some of these volatile byproducts are likely to show up in the distillate and these fermentation byproducts in ethanol could cause unpleasant flavours and affect human health if used for human consumption. There is some interest in improving ethanol quality, since human consumption represents a higher value. Advanced purification techniques, such as ozone oxidation, currently used for drinking water and municipal wastewater treatment, offer possibilities for adaptation in ethanol quality improvement. The development of analytical techniques has enabled the detection of low-concentration compounds and simple quality assurance of food-grade alcohol. This review includes the most recent ethanol production methods, potential ethanol purification techniques and analytical techniques. Application of such techniques would aid in the development of simplified alcohol production. Copyright © 2016 The Institute of Brewing & Distilling

This study examined the potential of using the filamentous fungus Rhizopus oligosporus as a feedstock for hydrothermal liquefaction (HTL). The fungal biomass, cultivated in thin stillage from a corn ethanol plant, was processed at pilot-scale using a 1.5-L capacity continuous-flow HTL system. HTL operating conditions of 300–400 °C at 27 MPa for 12–30 min were tested. Biocrude yields ranging from 48.2 to 60.9% were obtained. At low reaction temperatures (300 °C), yields as high as 59.9% could still be achieved. Aside from the least severe reaction condition studied (300 °C, 12 min), neither the yield nor elemental composition of the biocrude was significantly impacted by residence time or temperature, as is typically seen with batch reactors. Similarities in the biochemical and elemental composition between R. oligosporus and microalgae resulted in biocrude yields that were comparable to those previously reported for continuous-flow systems using microalgae. These findings demonstrate the viability of usin...

Aerial emissions of odorous volatile organic compounds (VOCs) are an important nuisance factor from livestock production systems. Reliable air sampling and analysis methods are needed to develop and test odor mitigation technologies. Quantification of VOCs responsible for livestock odor remains an analytical challenge due to physicochemical properties of VOCs and the requirement for low detection thresholds. A new air sampling and analysis method was developed for testing of odor/VOCs mitigation in simulated livestock emissions system. A flow-through standard gas generating system simulating odorous VOCs in livestock barn emissions was built on laboratory scale and tested to continuously generate ten odorous VOCs commonly defining livestock odor. Standard VOCs included sulfur VOCs (S-VOCs), volatile fatty acids (VFAs), and p-cresol. Solid-phase microextraction (SPME) was optimized for sampling of diluted odorous gas mixtures in the moving air followed by gas chromatography-mass spectrometry (GC-MS) analysis. CAR/PDMS 85μm fiber was shown to have the best sensitivity for the target odorous VOCs. A practical 5-min sampling time was selected to ensure optimal extraction of VFAs and p-cresol, as well as minimum displacement of S-VOCs. Method detection limits ranged from 0.39 to 2.64ppbv for S-VOCs, 0.23 to 0.77ppbv for VFAs, and 0.31ppbv for p-cresol. The method developed was applied to quantify VOCs and odorous VOC mitigation with UV light treatment. The measured concentrations ranged from 20.1 to 815ppbv for S-VOCs, 10.3 to 315ppbv for VFAs, and 4.73 to 417ppbv for p-cresol. Relative standard deviations between replicates ranged from 0.67% to 12.9%, 0.50% to 11.4%, 0.83% to 5.14% for S-VOCs, VFAs, and p-cresol, respectively. This research shows that a simple manual SPME sampler could be used successfully for quantification of important classes of odorous VOCs at concentrations relevant for real aerial emissions from livestock operations.

Fermentation of sugar to produce ethanol also produces volatile byproducts. This study was aimed at purifying corn-based ethanol for industrial and pharmaceutical use. The research was on treatment for 10 impurities removal after distillation. The ethanol headspace was sampled with solid-phase microextraction and analyzed with gas chromatography–mass spectrometry. A 40 mg/L ozone treatment resulted in >56% and >36% removal of styrene and 2-pentylfuran, respectively, without significant generation of byproducts. A 60 g/L activated carbon (AC) treatment with 270 min adsorption time resulted in 84%, >72%, and >78% removal of ethyl hexanoate, ethyl octanoate, and ethyl decanoate respectively. CO2-based stripping, at 675 LStripping gas/LSample, removed 65%, >82%, and >83% acetaldehyde, ethyl vinyl ether, and 1,1-diethoxyethane respectively. A combination of three approaches effectively removes these 8 impurities.

Fruit leathers (FLs) production produces some not-to-specification material, which contains valuable ingredients like fruit pulp, sugars and acidulates. Recovery of FL for product recycling requires decolorization. In earlier research, we proved the efficiency of an ozone-based decolorization process, however, it produces carbonyls as major byproducts, which could be of concern. A headspace solid-phase microextraction with on-fiber derivatization followed by gas chromatography-mass spectrometry was developed for 10 carbonyls analysis in ozonated FL solution/suspension. Effects of dopant concentration, derivatization temperature and time were studied. The adapted method was used to analyze ozonated FL solution/suspension samples. Dopant concentration and derivatization temperature were optimized to 17 mg/mL and 60 °C, respectively. Competitive extraction was studied, and 5 s extraction time was used to avoid non-linear derivatization of 2-furfural. The detection limits (LODs) for target carbonyls ranged from 0.016 and 0.030 µg/L. A much lower LOD (0.016 ppb) for 2-furfural was achieved compared with 6 and 35 ppb in previous studies. Analysis results confirmed the robustness of the adapted method for quantification of carbonyls in recycled process water treated with ozone-based decolorization. Ethanal, hexanal, 2-furfural, and benzaldehyde were identified as byproducts of known toxicity but all found below levels for concern.

Ethanol was produced via the simultaneous saccharification and fermentation (SSF) of dilute sodium hydroxide treated corn stover. Saccharification was achieved by cultivating either Phanerochaete chrysosporium or Gloeophyllum trabeum on the treated stover, and fermentation was then performed by using either Saccharomyces cerevisiae or Escherichia coli K011. Ethanol production was highest on day 3 for the combination of G. trabeum and E. coli K011 at 6.68 g/100 g stover, followed by the combination of P. chrysosporium and E. coli K011 at 5.00 g/100 g stover. SSF with S. cerevisiae had lower ethanol yields, ranging between 2.88 g/100 g stover at day 3 (P. chrysosporium treated stover) and 3.09 g/100 g stover at day 4 (G. trabeum treated stover). The results indicated that mild alkaline pretreatment coupled with fungal saccharification offers a promising bioprocess for ethanol production from corn stover without the addition of commercial enzymes.

Rhizopus oligosporus was cultivated on thin stillage from a dry-grind corn ethanol plant. The aim of the research was to develop a process to replace the current energy-intensive flash evaporation and make use of this nutrient-rich stream to create a new co-product in the form of protein-rich biomass. Batch experiments in 5- and 50-L stirred bioreactors showed prolific fungal growth under non-sterile conditions. COD, suspended solids, glycerol, and organic acids removals, critical for in-plant water reuse, reached ca. 80%, 98%, 100% and 100%, respectively, within 5 d of fungal inoculation, enabling effluent recycle as process water. R. oligosporus contains 2% lysine, good levels of other essential amino acids, and 43% crude protein - a highly nutritious livestock feed. Avoiding water evaporation from thin stillage would furthermore save substantial energy inputs on corn ethanol plants.

This study evaluated the effectiveness of ozone to reduce the presence of fungi in stored high-moisture maize. Maize at moisture contents of 18, 22 and 26% (wet basis) were treated with air having ozone concentrations of 0, 50, 500, 1000 and 15,000 ppm for 1 h at a flow rate of 0.5 L min � 1 . After treatment, maize samples were surface disinfected and fungal species e Aspergillus, Cladosporium, Curvularia, Fusarium, Mucor, Penicillium, and Rhizopus e enumerated in the samples. The response to grain moisture content varied with fungal species. The average fungal infections per 100 kernels of maize for the nonozone treated samples was 14.0 for Aspergillus, 0.6 for Cladosporium, 0.9 for Curvularia, 28.6 for Fusarium, 11.6 for Mucor, 56.9 for Penicillium, and 3.2 for Rhizopus. Ozone at the median concentrations e 500 and 1000 ppm e was most effective in reducing the presence of Aspergillus (p < 0.0001), Fusarium (p < 0.0001) and Mucor (p < 0.0001). Penicillium infections decreased with ozone concentrations of 1000 and 15,000 ppm (p < 0.0001). An ozone concentration of 15,000 ppm was necessary to reduce Rhizopus infection (p < 0.001). Ozone is capable of penetrating the surface of maize kernels to reduce fungal infections during storage. Ozonation of high-moisture maize is likely most effective in controlling the activity of Aspergillus and Fusarium due to their relatively high occurrence of infection on non-ozone treated maize and the observed reduction in their presence at lower ozone treatment concentrations.

Among many challenges faced in the commercial cultivation of microalgae, low-cost water and nutrients availability is crucial. Our study aimed at testing and optimizing two agro-industrial co-products, dry-grind ethanol thin stillage (TS) and soy whey (SW), as nutrient feedstock for mixotrophic/heterotrophic microalgal cultivation. Heterotrophic growth of Chlorella vulgaris was first optimized in a Bioscreen turbidimeter and 250 mL Erlenmeyer flasks, then scaled up to a 6-L stirred bioreactor. Intracellular oil was extracted from dried microalgal biomass by ultrasonication and solvent extraction treatments for yield comparison, and fatty acid (FA) profile. Biomass yields (dry basis) from TS, SW and modified basal medium (MBM) after 4 days of incubation at mixotrophic conditions in the bioreactor were 9.8, 6.3 and 8.0 g.L− 1 with oil content at 43, 11, and 27% (w/w) respectively. FA profile of oil samples was found to vary and depend on growth media characteristics. C. vulgaris when grown on TS and MBM produced oil richer in linoleic and linolenic acids, respectively. This research highlights the potential of two agro-industrial co-products as microalgal growth media with consequent production of high-value microalgal oil and biomass.

The research in this paper was aimed at finding a treatment method for recovery of fruit candy (fruit leathers) wastes. Fruit leather wastes were dissolved in water to investigate the efficacy of activated carbon adsorption to remove food colorants, which reduce recycling possibilities. The effects of initial pH (2.5–9), food colorant concentration (10–110 g fruit leather/L) and adsorbent dosage (1–12 g/L) on the adsorption process were investigated. Maximum adsorption was obtained at the original pH value of dissolved fruit candy waste in water. Maximum adsorbent capacities for red, yellow and blue food colorants were 4.4; 11.7 and 2 mg/g at pH 3.5 respectively. Regeneration of food colorant loaded activated carbon can be effected at 400 °C. Cost estimates indicate that red color removal would seem to be an economical proposition, costing about $19/ton fruit candy waste, yellow marginal at $70/ton waste, and blue uneconomical at $245/ton waste.

The effects of ultrasound on corn slurry saccharification yield and particle size distribution was studied in both batch and continuous-flow ultrasonic systems operating at a frequency of 20 kHz. Ground corn slurry (28%w/v) was prepared and sonicated in batches at various amplitudes (192-320 microm(peak-to-peak (p-p))) for 20 or 40s using a catenoidal horn. Continuous flow experiments were conducted by pumping corn slurry at various flow rates (10-28 l/min) through an ultrasonic reactor at constant amplitude of 12 microm(p-p). The reactor was equipped with a donut shaped horn. After ultrasonic treatment, commercial alpha- and gluco-amylases (STARGEN 001) were added to the samples, and liquefaction and saccharification proceeded for 3h. The sonicated samples were found to yield 2-3 times more reducing sugars than unsonicated controls. Although the continuous flow treatments released less reducing sugar compared to the batch systems, the continuous flow process was more energy efficient. The reduction of particle size due to sonication was approximately proportional to the dissipated ultrasonic energy regardless of the type of system used. Scanning electron microscopy (SEM) images were also used to observe the disruption of corn particles after sonication. Overall, the study suggests that both batch and continuous ultrasonication enhanced saccharification yields and reduced the particle size of corn slurry. However, due to the large volume involve in full scale processes, an ultrasonic continuous system is recommended.

Degradation of lignocellulosic biomass to sugars through a purely biological process is a key to sustainable biofuel production. Hydrolysis of the corn wet-milling co-product-corn fiber-to simple sugars by the brown rot fungus Gloeophyllum trabeum was studied in suspended-culture and solid-state fermentations. Suspended-culture experiments were not effective in producing harvestable sugars from the corn fiber. The fungus consumed sugars released by fungal extracellular enzymes. Solid-state fermentation demonstrated up to 40% fiber degradation within 9days. Enzyme activity assays on solid-state fermentation filtrates confirmed the involvement of starch- and cellulose-degrading enzymes. To reduce fungal consumption of sugars and to accelerate enzyme activity, 2- and 3-d solid-state fermentation biomasses (fiber and fungus) were submerged in buffer and incubated at 37 degrees C without shaking. This anaerobic incubation converted up to almost 11% of the corn fiber into harvestable reducing sugars. Sugars released by G. trabeum were fermented to a maximum yield of 3.3g ethanol/100g fiber. This is the first report, to our knowledge, of G. trabeum fermenting sugar to ethanol. The addition of Saccharomyces cerevisiae as a co-culture led to more rapid fermentation to a maximum yield of 4.0g ethanol/100g fiber. The findings demonstrate the potential for this simple fungal process, requiring no pretreatment of the corn fiber, to produce more ethanol by hydrolyzing and fermenting carbohydrates in this lignocellulosic co-product.

Sindhuja Sankaran, Samir Kumar Khanal, Nagapadma Jasti, Anthony L. Pometto III, J. Hans Van Leeuwen

The effects of ultrasound and heat pretreatments on ethanol yields from cassava chips were investigated. Cassava slurries were sonicated for 10 and 30 s at the amplitudes of 80, 160, and 320 μmpp (peak to peak amplitude in μm) corresponding to low, medium, and high power levels, respectively. The sonicated and non-sonicated (control) samples were then subjected to simultaneous liquefaction-saccharification and ethanol fermentation. Cassava starch-to-ethanol conversion efficiencies showed that higher ethanol yields were directly related to sonication times, but not to power levels. Significantly higher ethanol yields were observed only for sonicated samples at the high power level. The ethanol yield from the sonicated sample was 2.7-fold higher than yield from the control sample. Starch-to-ethanol conversion rates from sonicated cassava chips were also significantly higher; the fermentation time could be reduced by nearly 24 h for sonicated samples to achieve the same ethanol yield as control samples. Thus, ultrasound pretreatment enhanced both the overall ethanol yield and fermentation rate. When compared to heat-treated samples, the sonicated samples produced nearly 29% more ethanol yield. Combined heat and ultrasound treatment had no significant effect on overall ethanol yields from cassava chips. Ultrasound is also preferable to heat pretreatment because of lower energy requirements, as indicated by energy balances. Integration of ultrasound application in cassava-based ethanol plants can significantly improve ethanol yields and reduce the overall production costs.

The effects of high-powered ultrasonics on the conversion of sugary-2 maize (Zea Mays L.) to fermentable sugars were studied in this research. Ground sugary-2 maize mash was sonicated at 20 kHz and varying amplitudes (192–320 μmpeak-to-peak) for 5, 10, 15, 20 and 40 s. Stargen™ 0 0 1 enzyme, which contained both α-amylase and gluco-amylase was added to the samples following sonication to hydrolyze the starch into fermentable sugars. There was a 3-fold increase in sugar conversion rate of the sonicated samples in comparison with the control (unsonicated) samples. The ultrasonic relative net energy gain in the majority of the experimental design space was greater than 1.0. This indicates that the released of stored energy (output energy) from additional sugar released was greater than the dissipated ultrasonic energy (input energy), thus making ultrasonics an efficient treatment. Scanning electron microscopy (SEM) pictures revealed that the sugary starch was partially gelatinized during sonication. This observation was confirmed by polarized-light microscopic images, where a deformed “Maltese cross” was found. Swelling power for samples sonicated at 40 s reached 5.0 g/g while samples treated in conventional heating reached 4.0 g/g at 4 min treatment. It was also found that swelling power in the ultrasonicated sample initiated as quickly as 5 s and increased rapidly. These results are evident that ultrasonics can enhance swelling and gelatinization compared to conventional heating. As the saccharification time increased, a model was formulated to fit the sugar release curve. The findings indicated that there was a significant effect on enzymatic activity when enzymes were added to the sample during sonication. Additionally, jet cooking and ultrasonication obtained similar theoretical starch conversion results after 3 h saccharification. Thus, it is evident that ultrasonication could be considered a potential alternative to jet cooking.

This research focused on the use of high-power ultrasound prior to soy protein extraction to simultaneously enhance protein and sugar release in the extract. Defatted soy flakes dispersed in water were sonicated for 15, 30, 60 and 120 s using a bench-scale ultrasound unit. The ultrasonic amplitudes used were: 0, 21, 42, 63 and 84 μmpp (peak-to-peak). The respective power densities were 0.30, 0.87, 1.53 and 2.56 W/ml. Scanning electron micrographs of sonicated samples showed the structural disruption of soy flakes. The particle size decreased nearly 10-fold following ultrasonic treatment at high amplitudes. Sonication at high amplitude for 120 s gave the highest increase in total sugar released (50%) and protein yield (46%) when compared with non-sonicated samples (control). Ultrasonic pretreatment was also carried out with and without cooling for temperature moderation. The heat generated during sonication had no significant effect on protein and sugar release from defatted soy flakes. The use of ultrasound can significantly improve protein yield and reduce the overall cost of producing soy protein from flakes.

Two experiments were conducted to determine the effect of ozone treatment on controlling deterioration of high-moisture maize under extreme and moderate environmental conditions experienced during harvest. In the first experiment, 0.77-kg maize samples held at 22% moisture content were treated with ozone at 0.08, 0.16, 0.31, 0.62, 0.94, 1.25 and 1.56 mg kg maize −1 min −1 (60–1120 ppm ozone in air during application) for periods of 5 or 24 h, with an additional treatment of 1.56 mg min −1 repeated every 3 d, and stored at 32 °C for 9 d under continuous aeration. Ozone treatment decreased dry matter loss compared to the control, but not to a level that would likely justify ozone treatment at the rates and treatment times used. In the second experiment, 2.43-kg maize samples held at 26% moisture content were treated with ozonation rates of 0.25, 0.5, 1, and 2 mg kg maize −1 min −1 (1090–8680 ppm ozone during application) for 24 h, stored at 15.5 °C for 30 d and passively aerated every 3 d. Additional ozone treatments at the 2 mg kg maize −1 min −1 rate were applied for 1 h on 3-, 6-, and 12-d intervals throughout the experiment. Single ozone treatments of 1 and 2 mg kg maize −1 min −1 were equally effective, reducing dry matter loss by 1.3 percentage points compared to the control after 30 d of storage. Repeat treatments at 2 mg kg maize −1 min −1 did not reduce dry matter loss compared to the single treatment.

Wastewater from a corn wet-milling ethanol plant was treated with Rhizopus microsporus mold in a continuous biofilm reactor (attached growth system). Plastic composite support tubes, composed of 50% (w/w) polypropylene and 50% (w/w) agricultural products were used as support media. The effects of operating pH (3.5, 4.0, and 4.5) and hydraulic retention times (HRTs) (5.0, 3.75, 2.5, and 1.25 h) on fungal growth, chemical oxygen demand (COD) removal and unwanted bacterial growth were evaluated under nonaseptic conditions. COD removal and biomass production were highest at pH 4.0 with lowest bacterial competition. Maximum COD removal of up to 80% was achieved at a 5.0 h HRT with a biomass yield of 0.44 g volatile suspended solids per g COD removed. A higher biomass yield was achieved at a shorter HRT of 2.5 h due to increased substrate availability; however, the biofilm was more sensitive to changes in wastewater composition. A HRT of 3.5–4 h was considered optimal in achieving organic removal and fungal bio...

Pre-ozonation is often uneconomical for typical wastewaters with varied mixtures of organic compounds as more biodegradables than non-biodegradables are oxidized, all requiring ozone. The concept developed in this paper is ozonation within an activated sludge system to oxidize recalcitrant substances to more degradable forms and byproducts and to immediately assimilate or biodegrade these within the biological system. The focus was on a novel method of combining ozonation and biological treatment in one integrated unit without adversely affecting the bacterial population responsible for the biological degradation. An azo dye, spiked into the wastewater feed was used to study removal of a recalcitrant compound in a biological system.

This study aimed to determine the effect of pretreating defatted soy flakes with ultrasound on soy protein isolate (SPI) yield and functionality. Defatted soy flakes dispersed into water (16%, w/w) were sonicated for 30, 60 and 120 s at ultrasonic amplitudes of 21 and 84 µmpp (peak to peak amplitude in µm), representing low and high power, respectively. The power densities were 0.30 and 2.56 W mL−1, respectively. The SPI yield increased by 13 and 34%, after sonication for 120 s at low and high power, respectively. The sonication of defatted soy flakes for 120 s at the higher power level improved the SPI solubility by 34% at pH 7.0, while decreasing emulsification and foaming capacities by 12 and 26%, respectively, when compared to control SPI. Rheological behavior of the SPI was also modified with significant loss in consistency coefficient due to sonication. Some of these results could be explained by the loss of the protein native state with increased sonication time and power.

This research aims at developing a biorefinery platform to convert lignocellulosic corn fiber into fermentable sugars at a moderate temperature (37 °C) with minimal use of chemicals. White-rot (Phanerochaete chrysosporium), brown-rot (Gloeophyllum trabeum), and soft-rot (Trichoderma reesei) fungi were used for in situ enzyme production to hydrolyze cellulosic and hemicellulosic components of corn fiber into fermentable sugars. Solid-substrate fermentation of corn fiber by either white- or brown-rot fungi followed by simultaneous saccharification and fermentation (SSF) with coculture of Saccharomyces cerevisiae has shown a possibility of enhancing wood rot saccharification of corn fiber for ethanol fermentation. The laboratory-scale fungal saccharification and fermentation process incorporated in situ cellulolytic enzyme induction, which enhanced overall enzymatic hydrolysis of hemi/cellulose components of corn fiber into simple sugars (mono-, di-, and trisaccharides). The yeast fermentation of the hydrolyzate yielded 7.8, 8.6, and 4.9 g ethanol per 100 g corn fiber when saccharified with the white-, brown-, and soft-rot fungi, respectively. The highest ethanol yield (8.6 g ethanol per 100 g initial corn fiber) is equivalent to 35% of the theoretical ethanol yield from starch and cellulose in corn fiber. This research has significant commercial potential to increase net ethanol production per bushel of corn through the utilization of corn fiber. There is also a great research opportunity to evaluate the remaining biomass residue (enriched with fungal protein) as animal feed.

Pre-ozonation is often used to enhance the biodegradability of recalcitrant compounds prior to biological treatment of wastewater. A usual shortcoming of such an approach is wasting ozone on other compounds that are already biodegradable. This research followed a groundbreaking approach of degrading a recalcitrant substance with ozone during biological treatment. Two parallel bench-top activated sludge processes were fed a synthetic wastewater containing typical biodegradable substances and also methylene blue at 5 mg/L. Ozone was applied continuously and directly into one of the activated sludge units at 17 mg/L based on inflow rate. The methylene blue was removed by 95% in the ozonated process compared with just 40% removal in the non-ozonated control. The removal in the activated sludge without ozonation was demonstrated to be mainly due to biosorption. The ozone oxidation reaction by-products were analyzed using GC-MS on volatile substances collected in the headspace above ozonated samples of methylen...

Treatment of wet corn-milling wastewater with filamentous fungi was investigated as a means of obtaining fungal biomass as an additional byproduct. Competitive bacterial growth is a common problem during this nonaseptic treatment process. Selective disinfection with ozone was evaluated for eliminating bacterial populations during fungal cultivation. Three laboratory-scale continuous flow aerated reactors were operated under nonaseptic conditions at 38 °C, hydraulic retention time of 8 h and pH of 4. The bacterial population was reduced by one log with respect to the control when ozone was dosed at a concentration above 47 ± 2 mg/L. An ozone dosage of about 57 mg/L was found to be most effective in improving both fungal biomass production and soluble chemical oxygen demand (SCOD) removal (up to 90%). Fungal biomass concentration increased from c. 1.45 g/L (control) to c. 1.75 g/L at a 57-mg/L ozone dosage. Higher and lower dosages of ozone resulted in poorer fungal growth and lower SCOD removal.

The use of ultrasound pretreatment to enhance liquefaction and saccharification of cassava chips was investigated. Cassava chip slurry samples were subjected to sonication for 10–40 s at three power levels of low (2 W/mL), medium (5 W/mL), and high (8 W/mL). The samples were simultaneously exposed to enzymes to convert starch into glucose. The cassava particle size declined nearly 40-fold following ultrasonic pretreatment at high power input. Scanning electron micrographs of both unsonicated (control) and sonicated samples showed disruption of fibrous material in cassava chips but did not affect the granular structure of starch. Reducing sugar release improved in direct proportion to the power input and sonication time. The reducing sugar increase was as much as 180% with respect to the control groups. The slurry samples with enzyme addition during sonication resulted in better reducing sugar release than the samples with enzyme addition after sonication. The heat generated during sonication below starch gelatinization temperature apparently had no effect on the reducing sugar release. The reducing sugar yield and energy efficiency of ultrasound pretreated samples increased with total solids (TS) contents. The highest reducing sugar yield of 22 g/100 g of sample and efficiency of 323% were obtained for cassava slurry with 25% TS at high power. The reducing sugar yield at the completion of reaction (R∞) were over twofold higher compared to the control groups. The integration of ultrasound into a cassava-based ethanol plant may significantly improve the overall ethanol yield. Biotechnol. Bioeng. 2008;101: 487–496. © 2008 Wiley Periodicals, Inc.

The estrogenic hormones, for example, 17β-estradiol (E2) and estrone (El), are regarded as some of the most potent of natural endocrine-disrupting compounds. At levels of a few nanograms per liter, E2 and El can interfere with normal sexual development in some aquatic species and could impose as yet unknown hazards to ecosystems. Both E2 and El have been added to soil through livestock waste from concentrated animal feeding operations. However, the fate and transport of these compounds in soils are not easily predicted, partly as a result of analytical challenges at low environmental concentrations and because of a weak understanding of adsorption mechanisms at the water-soil interface. Estradiol and El adsorption experiments were carried out by batch tests with two Iowa soil materials, Hanlon sand and Zook silty clay. Residual estrogen concentrations in the aqueous phase were determined by solid-phase extraction and derivatization, followed by quantification using gas chromatography-negative chemical ionization-mass spectrometry. Aqueous estrogenic concentrations were measured, and uptake by the soil materials was calculated assuming mass balance. The adsorption data were fit by both the Freundlich and linear models, and partition coefficients, K d and K oc , were determined for each case. Over the entire range of concentrations studied, the linear model fit the sorption data well. Yet, at low equilibrium concentrations that could be determined by gas chromatography-negative chemical ionization-mass spectrome-try, the nonlinear Freundlich model provided a better fit.

The goal of this study was to develop a fungal process for ethanol production from corn fiber. Laboratory-scale solid-substrate fermentation was performed using the white-rot fungus Phanerochaete chrysosporium in 1 L polypropylene bottles as reactors via incubation at 37 degrees C for up to 3 days. Extracellular enzymes produced in situ by P. chrysosporium degraded lignin and enhanced saccharification of polysaccharides in corn fiber. The percentage biomass weight loss and Klason lignin reduction were 34 and 41%, respectively. Anaerobic incubation at 37 degrees C following 2 day incubation reduced the fungal sugar consumption and enhanced the in situ cellulolytic enzyme activities. Two days of aerobic solid-substrate fermentation of corn fiber with P. chrysosporium, followed by anaerobic static submerged-culture fermentation resulted in 1.7 g of ethanol/100 g of corn fiber in 6 days, whereas yeast ( Saccharomyces cerevisiae) cocultured with P. chrysosporium demonstrated enhanced ethanol production of 3 g of ethanol/100 g of corn fiber. Specific enzyme activity assays suggested starch and hemi/cellulose contribution of fermentable sugar.

Iron (Fe 2 O 3 ) and aluminum oxide (Al 2 O 3 ) were found to be good and inexpensive adsorbents for As(V) removal in drinking water despite their relatively small surface area. The experimental results for this study suggest that by careful selection of the relative concentration of arsenic, pH, and dosages of Fe 2 O 3 and Al 2 O 3 , As(V) removal efficiency as high as 99% can be achieved. At lower pH ( 2 O 3 and Al 2 O 3 and the initial concentration of As(V), over 95% of As(V) adsorption was observed within a contact time of 20–60 min. The adsorption of As(V) on Fe 2 O 3 and Al 2 O 3 , like that on other nonporous adsorbents, is mainly controlled by the surface area. The adsorption of As(V) on Fe 2 O 3 and Al 2 O 3 was found to follow the Langmuir isotherm between the pH values of 5 and 9. The maximum As(V) uptake values at pH 6 – the optimal pH value for adsorption – using Fe 2 O 3 and Al 2 O 3 , were calculated as 0.66 mg/g and 0.17 mg/g, respectively. No significant variation in the uptake of As(V) on Fe 2 O 3 as compared with Al 2 O 3 was observed at different pH values. The initial sorption rate of Fe 2 O 3 is higher than that of Al 2 O 3 . All these factors make Fe 2 O 3 a better adsorbent than Al 2 O 3 . Fe 2 O 3 is a useful and effective adsorbent for POE (pint of entry) and POU (point of use) water treatment systems, such as small-scale commercial or individual home water treatment systems. Even though the adsorption capacities of Fe 2 O 3 and Al 2 O 3 for As(V) are quite low compared with those of other absorbents, their low cost makes them useful adsorbents. They may be very useful in arsenic removal from water in endemic areas such as China, India, and Bangladesh.

Municipal wastewater sludge, particularly waste activated sludge (WAS), is more difficult to digest than primary solids due to a rate-limiting cell lysis step. The cell wall and the membrane of prokaryotes are composed of complex organic materials such as peptidoglycan, teichoic acids, and complex polysaccharides, which are not readily biodegradable. Physical pretreatment, particularly ultrasonics, is emerging as a popular method for WAS disintegration. The exposure of the microbial cells to ultrasound energy ruptures the cell wall and membrane and releases the intracellular organics in the bulk solution, which enhances the overall digestibility. This review article summarizes the major findings of ultrasonic application in WAS disintegration, and elucidates the impacts of sonic treatment on both aerobic and anaerobic digestion. This review also touches on some basics of ultrasonics, different methods of quantifying ultrasonic efficacy, and some engineering aspects of ultrasonics as applied to biological ...

Pilot plant studies were conducted to evaluate the performance of a polymeric ferric sulfate (PFS) coagulant synthesized from waste SO2. Aluminum sulfate (alum), ferric sulfate and ferric chloride were compared with PFS. Preliminary jar tests were performed to determine coagulant dose range and expected turbidity removal. The studies were conducted at the City of Savannah Industrial and Domestic (I&D) Water Treatment Plant in Port Wentworth, GA. The raw water source, a tributary of the Savannah River, was high in organic content. Due to its proximity to the coast, the tributary is tidally affected resulting in continuous water quality changes. Of the three iron-based coagulants tested, all provided nearly 10% greater reductions in total organic carbon when compared to alum. The pH ranges using the iron-based coagulants were much lower than those experienced with alum. Turbidity removal was approximately 100% for all coagulants. Ferric sulfate required the highest average dosage for proper coagulation/flocculation with efficient turbidity removal at 110 ppm. The performance of the PFS was comparable to that of ferric sulfate.

This work evaluated the use of high power ultrasonic energy to treat corn slurry in dry corn milling ethanol plants to enhance liquefaction and saccharification for ethanol production. Corn slurry samples obtained before and after jet cooking were subjected to ultrasonic pretreatment for 20 and 40 s at amplitudes of vibration ranging from 180 to 299 microm(pp) (peak to peak amplitude in microm). The resulting samples were then exposed to enzymes (alpha-amylase and glucoamylase) to convert cornstarch into glucose. A comparison of scanning electron micrographs of raw and sonicated samples showed the development of micropores and the disruption of cell walls in corn mash. The corn particle size declined nearly 20-fold following ultrasonic treatment at high power settings. The glucose release rate from sonicated samples increased as much as threefold compared to the control group. The efficiency of ultrasound exceeded 100% in terms of energy gain from the sugar released over the ultrasonic energy supplied. Enzymatic activity was enhanced when the corn slurry was sonicated with simultaneous addition of enzymes. This finding suggests that the ultrasonic energy did not degrade or denature the enzymes during the pretreatment.

Waste activated sludge (WAS) is more difficult to digest than primary sludge due to rate limiting cell hydrolysis. High-power ultrasound can effectively disintegrate the bacterial cells and thus enhance the subsequent digestion. This research examines the effectiveness of ultrasound pretreatment on WAS disintegration at different specific energy inputs, ultrasonic densities and total solids (TS) contents. The results show that the cut diameter (d50) for WAS with 2% TS content declined nearly 6.5-fold at an ultrasonic density of 0.67 W/ml. For higher TS contents of 4 and 6%, higher densities of 1.03 and 0.86 W/ml, respectively, were needed to achieve the same degree of particle size reduction. The efficacy of ultrasonic disintegration measured as soluble chemical oxygen demand (SCOD) release was primarily governed by ultrasonic density (W/ml); whereas ultrasonic density did not show a significant effect on protein release at all TS levels. SCOD release of about 320 mg SCOD/g TS was obtained at a TS content of 2% and specific energy input of 5 kWs/gTS. The SCOD release, however, decreased to 160 and 90 mgSCOD/gTS at 4 and 6% TS contents, respectively. The highest protein release of 73 mg/gTS was obtained at a TS content of 2% and specific energy input of 10 kWs/gTS. The sludge disintegration efficiency declined significantly at higher TS content. Thus, there is a limiting TS concentration that could be effectively disintegrated by ultrasound, and this is governed by the capability of an ultrasonic unit in producing cavitation. The degree of disintegration also depends on types of ultrasonic unit used.

Natural steroidal estrogen hormones, e.g., estrone (E1), 17beta-estradiol (E2), estriol (E3), and 17alpha-estradiol (17alpha), are released by humans and livestock in the environment and are the most potent endocrine disrupters even at nanogram per liter levels. Published studies broadly conclude that conventional wastewater treatment is efficient in the removal of 17beta-estradiol (85-99%), but estrone removal is relatively poor (25-80%). The removal occurs mainly through sorption by sludge and subsequent biodegradation. The long solids retention time in wastewater treatment systems enhances estrogen removal due to longer exposure and the presence of a diverse microbial community, particularly nitrifiers. In spite of the treatment, the effluent from conventional biological wastewater treatment systems still contains estrogenic compounds at a level that may cause disruption of endocrine systems in some species. Advanced wastewater treatment systems such as membrane processes remove the estrogen compounds mainly through physical straining of particle-bound estrogens. Another major source, which accounts for 90% of the estrogen load, is animal manure from concentrated animal-feeding operations (CAFOs). Manure is not required to be treated in the United States as long as it is not discharged directly into water bodies. Thus, there is an urgent need to study the fate of animal-borne estrogens from these facilities into the environment. A number of studies have reported the feminization of male aquatic species in water bodies receiving the effluents from wastewater treatment plants (WWTPs) or surface runoff from fields amended with livestock manure and municipal biosolids. Estrogenicity monitoring studies have been conducted in more than 30 countries, and abundant research articles are now available in refereed journals. This review paper focuses on estrogen contributions by wastewater and livestock manure, their removal rate and mechanisms in an engineered system, and their transport and ultimate fate in an engineered system and the environment. The review aims to advance our understanding of fate, transport, and biodegradation of estrogen compounds and outlines some directions for future research.

The emission of volatile organic compounds from byproduct streams during drying is a major concern in the dry-mill production of ethanol. Thermogravimetric analysis on distiller's wet grains, distiller's dried grains after the first drier, distiller's dried grains after the second drier, and syrup was conducted to acquire information on the loss of volatiles as a function of temperature. Results show that there is a weight loss in all the samples in the temperature range of 25–100 °C and this weight loss is expected to be mainly due to moisture. It is also observed that devolatilization takes place in distiller's dried grains collected after the first and second rotary driers in between 125 and 220 °C.

This paper studies the reaction between SO 2 and calcium lactate, which potentially can be used to recover lactic acid from the anaerobic fermentation broth of an SO 2 waste stream. The conversion of given amounts of calcium lactate to lactic acid was evaluated under different reaction temperatures and flow rates of SO 2 . Analyses of concentrations of the produced lactic acid indicated that the reactions between SO 2 and calcium lactate were complete under all experimental conditions.

Poly ferric sulfate (PFS) was synthesized by absorbing a dilute sulfur dioxide gas stream into a bench-scale reactor containing a stirred solution of ferrous sulfate, with sodium chlorate added as an oxidant. The reaction product was a solution containing approximately 50 wt.% PFS, a highly effective coagulant used in water treatment. The reaction took place near atmospheric pressure and at temperatures of 30–80 °C. SO2 removal efficiencies greater than 90% were achieved with ferrous iron concentrations of less than 0.1% in the product. The product solution was evaluated by wet chemistry methods to verify that the process was capable of consistently producing high quality PFS. Quality parameters examined were total iron concentration, ferrous iron concentration, basicity (mass ratio of OH/Fe(III)), density, and pH. The PFS product was used in pilot-scale tests at a municipal water treatment facility, and gave good results in the removal of turbidity and superior results in the removal of organic materials when compared with equal doses of ferric chloride.

This paper discusses the corrosion behavior of two coagulants used in water treatment, ferric chloride (FC) and polymeric ferric sulfate (PFS). Corrosion tests were performed to compare the corrosivity of these two coagulants on aluminum 6061 and steel 4140 specimens. Results showed that both temperature and concentration of the coagulants substantially impact corrosion rates. The corrosion rates increased with the increase of temperature and concentration. The results from a scanning electron microscope (SEM) showed that chloride caused more serious pitting than sulfate anion on both aluminum and steel specimens. Although SEM confirmed the existence of pitting corrosion, the results of weight loss indicated that the uniform corrosion predominate the corrosion mechanism, and pitting corrosion played a less important role. The test proved that PFS was less corrosive than FC, which may lead to the large-scale application of PFS in waste treatment in the near future.

The potential of ozone for disinfection of ships’ ballast water was investigated using Bacillus subtilis spores as an indicator. The effects of pH, presence of iron, and bacterial strain on disinfection efficacy in seawater, under simulated ballast conditions, were investigated. Ozone dosages of 9 mg/L (pH 7) and 14 mg/L (pH 8.2) and 24 h contact achieved a 4-log inactivation with the various oxidant residuals formed. Iron surface at a ratio to water of 9 m2/m3 impaired the oxidant residuals and the disinfection of spores. Different strains of B. subtilis resulted in different CT values. Ozone does not seem to be a good choice for the control of spore-forming organisms in ballast water, but may be suitable for the control of other species.

Use of sulfur dioxide (SO2) in the production of polymeric ferric sulfate (PFS) was investigated. PFS is a highly effective coagulant useful in treatment of drinking water and wastewater, and could serve as a value-added sink for sulfur removed during coal gas cleanup. SO2 was absorbed from a dilute gas stream by sparging it into a bench-scale reactor containing a stirred solution of ferrous sulfate with sodium chlorate added as an oxidant. The reaction took place near atmospheric pressure and at temperatures of 30–80 °C, and produced a solution containing approximately 50 wt.% PFS. SO2 removal efficiencies greater than 90% were achieved with ferrous iron concentrations in the product less than 0.1%. Other PFS quality parameters were also monitored, including total iron content, basicity, and pH. A factorial analysis of the effect of temperature, oxidant dosage, SO2 concentration, and gas flow rate on SO2 removal efficiency is presented. In general, higher synthesis temperatures increased iron conversion rates while decreasing SO2 removal efficiency, and increased oxidant dosages had a positive correlation with removal efficiency. In addition, X-ray diffraction analyses showed that all dried PFS samples were found to be highly amorphous regardless of drying conditions.

This paper studies the kinetics of reactions between iron and aluminum oxides in fly ash and sulfuric acid for the production of a complex sulfate-based coagulant. The important part of this research was to monitor the change in the concentration of product during the reaction. The ratio of concentration of ferric sulfate to aluminum sulfate during reaction, and the linearity of plots of a derived concentration of function versus time at different temperatures show that reactions of both iron and aluminum oxides in fly ash with sulfuric acid are second-order with respect to sulfuric acid concentration. Furthermore, the ratio of the concentration of the ferric sulfate to that of aluminum sulfate and the slopes of the derived concentration function versus time were used to obtain the rate constants of reactions. Finally, based on the rate constants obtained at different temperatures, the empirical Arrhenius expressions of iron and aluminum extracting reactions were derived.