Chang-Six Ra

Recovery of struvite from animal wastewater and its nutrient leaching loss in soil

Contaminants in swine wastewater were recovered in the form of struvite, a crystal of magnesium ammonium phosphate (MAP), using a newly designed process, and the leaching loss of MAP in soil was examined. The continuous flow process was operated under optimal conditions: 1.0 molar ratio of magnesium (Mg) addition with respect to orthophosphate (OP) and an aeration rate of 0.73 L/L min. Five treatments were performed with three replications for soil pH and nutrient leaching loss tests. It was found that 93% of the OP in the swine wastewater was crystallized, and the MAP crystal formation was verified by X-ray diffraction (XRD) and scanning electron microscope (SEM) analyses. The analyses revealed that the pattern of pH change and N leaching losses for MAP-treated soil were remarkably different from those for fused super phosphate (FSP)-urea-treated soils. The pH levels for the control and FSP-urea-treated soils after a five-week experiment were unchanged or slightly decreased, whereas an increase in pH was observed in the MAP-treated soils. Leaching loss of N was higher in FSP-urea treatments, with MAP treatments showing N losses of only 1.93 and 2.05%, respectively, while FSP-urea treatments showed N losses of 7.82 and 6.47%, respectively, during the same period. Phosphate (P) leaching was very slow in both MAP- and FSP-treated groups.

Dose effects of Mg and PO4 sources on the composting of swine manure.

A series of experiments were performed to study the effects of magnesium (Mg) and phosphate (PO(4)) addition on the decomposition of organic matter and struvite formation during the composting of swine manure. In these experiments, different amounts of magnesium chloride (MgCl(2)) with or without PO(4) salts were added to the samples, and the optimum molar ratio of Mg and PO(4) to the total nitrogen (TN) in swine manure was studied. The temperature profiles revealed that no organic matter was decomposed when 0.1M or more Mg and PO(4) salts were added and that when 0.05 M ratio of Mg and PO(4) salts was added, the addition inhibited the composting process. However, the thermophilic condition was readily established if only Mg salt was added. Further, the addition of only Mg salt easily established an optimum thermophilic condition even at a higher level. The highest amount of NH(3) was emitted when no Mg or PO(4) salts was added, and the rate of NH(3) emission was inversely proportional to the salt level. The orthophosphate/total phosphorus ratio (OP/TP) proportionally increased with the PO(4) amount added before composting but decreased after composting. In contrast, when only Mg was added, the OP/TP ratio proportionally decreased before composting and increased after composting. However, when more than 0.075 molar ratio of Mg was added, the OP/TP ratio decreased after composting; this result was identical to that obtained when both Mg and PO(4) salts were added. The decrease in the OP/TP ratio before or after composting could be due to the formation of magnesium ammonium phosphate (MAP) crystals. The study revealed that adding less than 0.05 M of both Mg and PO(4) salt or more than approximately 0.07 molar ratio of Mg with regard to the TN content was acceptable for the proper decomposition of organic matters and the continuous formation of struvite during the composting of swine manure.

Recycle of electrolytically dissolved struvite as an alternative to enhance phosphate and nitrogen recovery from swine wastewater

Operational parameters such as electric voltage, NaCl, reaction time (RT) and initial struvite amount were optimized for struvite dissolution with a designed electrolysis reactor, and the effect of recycling the dissolved solution on the performance of struvite crystallization was also assessed. The electrolytic reactor was made of plexiglas having titanium plate coated with iridium oxide as anode (surface area: 400 cm(2)) and stainless steel plates as cathodes. For reutilization of dissolved struvite, four runs were conducted with different recycle ratio of the solution. Optimum conditions for the electric voltage, NaCl, RT and initial struvite amount were 7 V, 0.06%, 1.5h and 1.25 g/L, respectively. At the above optimized conditions, 49.17 mg/L phosphate (PO(4)(3-)-P) was dissolved and ammonium-nitrogen (NH(4)-N) got completely removed from the solution. When 0.0, 0.5, 1.0 and 2.0 moles of the dissolved struvite with respect to PO(4)(3-)-P in swine wastewater were recycled along with 0.5M magnesium chloride (MgCl(2)), the PO(4)(3-)-P removal was 63, 69, 71 and 79%, and NH(4)-N was 9, 31, 40 and 53%, respectively. Hence, the performance of struvite formation process was proportionally increased. It is concluded that struvite can be re-dissolved by electrolysis and reused as a source of P and Mg.

Effects of electric voltage and sodium chloride level on electrolysis of swine wastewater.

The effects of electric voltage and NaCl concentration on the removal of pollutants in swine wastewater were investigated to determine the optimum operation conditions for a designed electrolysis process. An up-flow electrolytic reactor was fabricated from Plexiglas, and one titanium anode coated with iridium oxide (IrO(2)) and two stainless steel cathodes were installed in it. The anode surface area was 80 cm(2)/L and the hydraulic retention time (HRT) was 6h. The results indicated that the pollutant removal was highly proportional to the electric voltage and removal could be enhanced by adding NaCl. The removal efficiencies of NH(4)-N, soluble nitrogen (NH(4)-N plus NO(x)-N), soluble total organic carbon (STOC), and color were proportional to the NaCl level up to 0.05% NaCl level, beyond which no further enhancement in removal was observed. However, such a tendency was not observed in the case of PO(4)-P removal. The obtained results indicate that 7 V and 0.05% (8.56 mM) NaCl level would be the optimum conditions for the designed electrolysis process. Under these conditions, the average removal efficiencies of NH(4)-N, soluble nitrogen, PO(4)-P, STOC, and color were 99%, 94%, 59%, 64%, and 93%, respectively.

Effects of Dietary Garlic Extract on Growth, Feed Utilization and Whole Body Composition of Juvenile Sterlet Sturgeon (Acipenser ruthenus)

This study was carried out to investigate the supplemental effects of dietary garlic extract (GE) on growth performance of juvenile sterlet sturgeon (Acipenser ruthenus). The first experiment was designed to determine the optimum levels of garlic extract as growth promoter during 10 weeks. Three groups (two replicates/group) of 240 fish with mean body weight of 85 g were fed with diets containing 0 (control), 0.5 and 1.0% of GE. The highest weight gain (%) and feed efficiency (%) were found in fish groups fed with diet containing 0.5% GE. Subsequently, the supplemental effects of dietary GE was studied on growth of juvenile sterlet sturgeon (Acipenser ruthenus) with an average body weight of 59.6 g. Fish cultured in freshwater were randomly allotted to each of 10 tanks (two groups of five replicates, 20 fish/tank) and fed diets with 0.5% GE or without GE (control), respectively, at the level of 2.0% of fish body weight per day for 5 weeks. Weight gain (51.1%), feed efficiency (79.1%), specific growth rate (1.18%) and protein efficiency ratio (1.50) of fish fed 0.5% GE were significantly (p<0.05) higher than those fish fed the control diet. Significantly higher protein (PRE 20.4%) and lipid retention efficiencies (LRE, 74.5%) were also found in 0.5% GE group (p<0.05). The present results suggested that dietary GE could improve growth and feed utilization of juvenile sterlet sturgeons.

Real-time control of oxic phase using pH (mV)-time profile in swine wastewater treatment

The feasibility of real-time control of the oxic phase using the pH (mV)-time profile in a sequencing batch reactor for swine wastewater treatment was evaluated, and the characteristics of the novel real-time control strategies were analyzed in two different concentrated wastewaters. The nitrogen break point (NBP) on the moving slope change (MSC) of the pH (mV) was designated as a real-time control point, and a pilot-scale sequencing batch reactor (18 m(3)) was designed to fulfill the objectives of the study. Successful real-time control using the developed control strategy was achieved despite the large variations in the influent strength and the loading rate per cycle. Indeed, complete and consistent removal of NH4-N (100% removal) was achieved. There was a strong positive correlation (r(2)=0.9789) between the loading rate and soluble total organic carbon (TOCs) removal, and a loading rate of 100 g/m(3)/cycle was found to be optimum for TOCs removal. Experimental data showed that the real-time control strategy using the MSC of the pH (mV)-time profile could be utilized successfully for the removal of nitrogen from swine wastewater. Furthermore, the pH (mV) was a more reliable real-time control parameter than the oxidation-reduction potential (ORP) for the control of the oxic phase. However, the nitrate knee point (NKP) appeared more consistently upon the completion of denitrification on the ORP-time profile than on the pH (mV)-time profile.

Effects of Dietary Garlic Powder on Growth, Feed Utilization and Whole Body Composition Changes in Fingerling Sterlet Sturgeon, Acipenser ruthenus.

A 12 week growth study was carried out to investigate the supplemental effects of dietary garlic powder (GP) on growth, feed utilization and whole body composition changes of fingerling sterlet sturgeon Acipenser ruthenus (averaging weight, 5.5 g). Following a 24-h fasting, 540 fish were randomly distributed to each of 18 tanks (30 fish/tank) under a semi-recirculation freshwater system. The GP of 0.5% (GP0.5), 1% (GP1), 1.5% (GP1.5), 2% (GP2) and 3% (GP3) was added to the control diet (GP0) containing 43% protein and 16% lipid. After the feeding trial, weight gain (WG) of fish fed GP1.5, GP2 and GP3 were significantly higher (p<0.05) than those of fish fed GP0, GP0.5 and GP1. Feed efficiency and specific growth rate (SGR) showed a similar trend to WG. Protein efficiency ratio of fish fed GP1.5, GP2, and GP3 were significantly higher (p<0.05) than those of fish groups fed the other diets. A significant difference (p<0.05) was found in whole body composition (moisture, crude protein, crude lipid, ash, and fiber) of fish at the end of the experiment. Significantly higher (p<0.05) protein and lipid retention efficiencies (PRE and LRE) were also found in GP1.5, GP2, and GP3 groups. Broken-line regression model analysis and second order polynomial regression model analysis relation on the basis of SGR and WG indicated that the dietary optimal GP level could be greater than 1.77% and 1.79%, but less than 2.95% and 3.18% in fingerling sterlet sturgeon. The present study suggested that dietary GP for fingerling sterlet sturgeon could positively affect growth performance and protein retention.

Effects of Fermented Feedstuff with Wet Brewer’s Grain and Soybean on Fattening Performance and Carcass Grade in hanwoo Steers

This study was conducted to examine the feeding effects of FFWBG (fermented feedstuff with wet brewer’s grain) and GS(grinding soybean) in Hanwoo steers. For this research, total twenty steers(average body weight : 455.725.9kg) were grouped into control(formula feed), T1(formula feed:FFWBG=60:40), T2(formula feed:GS=80:20), T3(formula feed:FFWBG:GS=50:40:10), and T4(formula feed: FFWBG:GS=40:40:20), each treatment was allocated to four steers. There was a tendency to be increased average daily gain in T1, T2, T3 and T4 compared with the control even though no statistical significance was found. The feed conversion of T1, T2, T3 and T4 were beneficially better than that of control(P, respectively). The back-fat thickness of T3 was thicker than that of control, T1, T2 and T4. The rib-eye area of T1, T3 and T4 was wider than that of control. Appearances percentage of ‘A’ ranked meat quantity were 66, 33, 75 and 33% in control, T1, T2 and T4, respectively.

Effects of Dietary Garlic Extracts on Whole Body Amino Acid and Fatty Acid Composition, Muscle Free Amino Acid Profiles and Blood Plasma Changes in Juvenile Sterlet Sturgeon, Acipenser ruthenus

A series of studies were carried out to investigate the supplemental effects of dietary garlic extracts (GE) on whole body amino acids, whole body and muscle free amino acids, fatty acid composition and blood plasma changes in 6 month old juvenile sterlet sturgeon (Acipenser ruthenus). In the first experiment, fish with an average body weight of 59.6 g were randomly allotted to each of 10 tanks (two groups of five replicates, 20 fish/tank) and fed diets with (0.5%) or without (control) GE respectively, at the level of 2% of fish body weight per day for 5 wks. Whole body amino acid composition between the GE and control groups were not different (p>0.05). Among free amino acids in muscle, L-glutamic acid, L-alanine, L-valine, L-leucine and L-phenylalanine were significantly (p<0.05) higher in GE than in control. However, total whole body free amino acids were significantly lower in GE than in control (p<0.05). GE group showed higher EPA (C22:6n3) and DHA (C22:5n3) in their whole body than the other group (p<0.05). In the second experiment, the effects of dietary garlic extracts on blood plasma changes were investigated using 6 month old juvenile sterlet sturgeon averaging 56.5 g. Fish were randomly allotted to each of 2 tanks (300 fish/tank) and fed diets with (0.5%) or without (control) GE respectively, at the rate of 2% of body weight per day for 23 d. At the end of the feeding trial, blood was taken from the tail vein (n = 5, per group) at 1, 12, and 24 h after feeding, respectively. Blood plasma glucose, insulin and the other serological characteristics were also measured to assess postprandial status of the fish. Plasma glucose concentrations (mg/dl) between two groups (GE vs control) were significantly (p< 0.05) different at 1 (50.8 vs 62.4) and 24 h (57.6 vs 73.6) after feeding, respectively, while no significant difference (p>0.05) were noticed at 12 h (74.6 vs 73.0). Plasma insulin concentrations (μIU/ml) between the two groups were significantly (p<0.05) different at 1 (10.56 vs 5.06) and 24 h (32.56 vs 2.96) after feeding. The present results suggested that dietary garlic extracts could increase dietary glucose utilization through the insulin secretion, which result in improved fish body quality and feed utilization by juvenile sterlet sturgeon.

Nutrient production from dairy cattle manure and loading on arable land

Objective Along with increasing livestock products via intensive rearing, the accumulation of livestock manure has become a serious issue due to the fact that there is finite land for livestock manure recycling via composting. The nutrients from livestock manure accumulate on agricultural land and the excess disembogues into streams causing eutrophication. In order to systematically manage nutrient loading on agricultural land, quantifying the amount of nutrients according to their respective sources is very important. However, there is a lack of research concerning nutrient loss from livestock manure during composting or storage on farms. Therefore, in the present study we quantified the nutrients from dairy cattle manure that were imparted onto agricultural land. Methods Through investigation of 41 dairy farms, weight reduction and volatile solids (VS), total nitrogen (TN), and total phosphorus (TP) changes of dairy cattle manure during the storage and composting periods were analyzed. In order to support the direct investigation and survey on site, the three cases of weight reduction during the storing and composting periods were developed according to i) experiment, ii) reference, and iii) theoretical changes in phosphorus content (ΔP = 0). Results The data revealed the nutrient loading coefficients (NLCs) of VS, TN, and TP on agricultural land were 1.48, 0.60, and 0.66, respectively. These values indicated that the loss of nitrogen and phosphorus was 40% and 34%, respectively, and that there was an increase of VS since bedding materials were mixed with excretion in the barn. Conclusion As result of nutrient-footprint analyses, the amounts of TN and TP particularly entered on arable land have been overestimated if applying the nutrient amount in fresh manure. The NLCs obtained in this study may assist in the development of a database to assess the accurate level of manure nutrient loading on soil and facilitate systematic nutrient management.