Literature on existing systems for slaughterhouse wastewater treatment was reviewed and discussed in terms of technology usefulness and relevance under Canadian conditions. The wastewater from six hog slaughterhouses in Quebec and Ontario was also characterised before and after treatment at the plant. In raw wastewater, total chemical oxygen demand (TCOD) ranged from 2333 to 8627 mg/L and suspended solids (SS) varied between 736 and 2099 mg/L. Slaughterhouse wastewater composition in terms of organic strength, inorganic elements, alkalinity, and pH is adequate for biological treatment. Two slaughterhouses only settled their wastewater before discharging it to the: municipal sewer. Three plants used primary treatment to precipitate blood and remove floating fat, while one further treated its wastewater using an aerobic trickling filter. Although preliminary treatment at the slaughterhouse reduced the level of pollutants, TCOD and SS concentrations were still too high for sewer discharge without being imposed a municipal surcharge. In addition, all treatments produced large amounts of putrefactive and bulky sludge, which required special handling and/or further treatment.
Tang, Z. and Cenkowski, S. 2000. Dehydration dynamics of potatoes in superheated steam and hot air. Can. Agric. Eng. 42:043-049. Superheated-steam at atmospheric pressure is an alternative drying medium for dehydrating materials insensitive to temperature equal to or above 100°C. This research compared the dehydration characteristics, temperature histories, drying rates, and overall moisture diffusivities of cylindrical potato samples exposed to superheated steam and hot air at 125, 145, and 165°C. A small amount of moisture (0.18 to 0.47 kg/kg db, dry basis) dependent on the steam temperature was gained from steam condensation on the sample surface during the warm-up period from the superheated-steam. The temperature of the drying medium had a greater effect on the drying rate, overall moisture diffusivity, and consequently dehydration time for the superheatedsteam dehydration than for the hot-air dehydration. Increasing the temperature from 125 to 165°C decreased the dehydration time by 60 and 24% for the superheated-steam and hot-air dehydration, respectively. A constant-rate drying period was only observed with superheated steam at 125 and 145°C. There existed an inversion temperature point between 145 to 165°C for the first dehydration stage
The effects of storage temperature, storage time, and compaction of compressed flour on functional and rheological properties of dough were investigated for flour milled from No. 1 Canadian Western Red Spring wheat. Untreated (loose) flour and flour that had been mechanically compacted to a 55% volume reduction were stored for one year at 20, 30, and 40 degrees C. An imitative rheological test (capillary rheometry) indicated that compaction of 75% extraction rate flour had a marked effect on the magnitude of the flow behaviour index (n). This effect was not observed in 83% extraction rate flour. Storage time had a substantial effect on all samples, increasing the n values by 5 to 15%. A similar effect was observed for consistency coefficient. Alveograph and farinograph results indicated that the main factor affecting the oxidation of compacted and loose flours during storage was the storage temperature. Compaction of flour appeared to have a slight mitigating effect on changes to alveograph curves during storage. Storage of flour up to 30 degrees C caused changes in dough rheological parameters, indicating a dough strengthening effect. Storage of flour at 40 degrees C resulted in tight inextensible dough that would be difficult to process in bakeries. Capillary extrusion tests confirmed that the flow behaviour index was noticeably affected by storage temperature.
Experiments were conducted to investigate the quantity and quality of the chopped alfalfa pulp and juice extracted in a piston-cylinder assembly. Single- and double-macerated alfalfa chops at an initial moisture content of 75.7% (wet mass basis) were pressed under constant or increasing pressures up to 20 MPa. The pressed pulp and the juice were analyzed for the contents of dry matter, protein, and beta -carotene. Approximately 52% of the total water content was removed at pressures higher than ii MPa. The pressure required to extract extra juice from already pressed pulp increased exponentially. The juice had on average solids content of 10-12% (dry mass basis). On a dry matter basis, there were no reductions in either protein content or beta -carotene in the pulp.
Several conditioning treatments to promote dehulling of canola grain (Brassica napus L.) were investigated. The tested treatment sequences were: (1) moistening, heating; (2) heating, moistening; and (3) heating. Moistening was done by spraying a predetermined quantity of water on the grain. A thin layer dryer and a fluidized bed dryer were used to heat/dry the grain. Following each treatment, the samples were dehulled in an abrasive dehuller. The dehulled samples were fractionated on an aspirator. A dehulling index was evaluated considering four mass fractions of cotyledon, hulls, undehulled grains, and fines. The maximum dehulling index of 0.88 (dehulling index ranges from -1 to +1) was achieved by moistening the grain to about 15% moisture content (wet basis) for 10 min followed by heating at 70-75 degrees C for 5 min. A similar dehulling index was achieved by heating the grain at 120 degrees C for 5 min without moistening. The control grain had a dehulling index of -0.47.
Yang, C.-C., Prasher, S.O., Landry, J.-A., Ramaswamy, H.S. and DiTommaso. 2000. Application of artificial neural networks in image recognition and classification of crop and weeds. Can. Agric. Eng. 42:147-152. The objective of this study was to develop a backpropagation artificial neural network (ANN) model that could distinguish young corn plants from weeds. Although only the colour indices associated with image pixels were used as inputs, it was assumed that the ANN model could develop the ability to use other information, such as shapes, implicit in these data. The 756x504 pixel images were taken in the field and were then cropped to 100x100-pixel images depicting only one plant, either a corn plant or weeds. There were 40 images of corn and 40 of weeds. The ability of the ANNs to discriminate weeds from corn was then tested on 20 other images. A total of 80 images of corn plants and weeds were used for training purposes. For some ANNs, the success rate for classifying corn plants was as high as 100%, whereas the highest success rate for weed recognition was 80%. This is considered satisfactory, given the limited amount of training data and the computer hardware limitations. Therefore, it is concluded that an ANN-based weed recognition system can potentially be used in the precision spraying of herbicides in agricultural fields.
Results are presented from a study concerning the reduction in soil hydraulic conductivity due to ponded hog manure. Of specific interest is how much of the reduction is 'at the soil surface' as opposed to within the soil. Seven different soils with clay contents ranging from 9 to 33% were studied using 200 mm long soil columns in a low-temperature (5-6 degreesC) environment. Hydraulic conductivities, as measured with water, ranged between 3.0 x 10(-8) and 1.3 x 10(-6) m/s before manure application. Fresh hog manure was ponded on these soil columns for a period of 634 days. Hydraulic conductivity, for all soils, decreased rapidly to about 1.0 x 10(-9) m/s and maintained this value except during the time of failure of the cooling system. A black layer was observed to have developed at the manure-soil interface of all columns within 36 hours of manure pending. Visual observations conducted between days 136 and 618 showed that the black layer grew downwards into the soil at a rate of 0.3 mm/month. The hydraulic conductivities of the soils at different depth intervals indicated that most, if not all, of the reduction occurred at the black surface layer. At the end of the 634 day period, the black layer was removed and soil hydraulic conductivities were measured once again using a prepared chemical solution of similar ionic concentration to that of manure. The hydraulic conductivities of all soils increased to that of 'pre-manure' conditions. The results of this study suggest that the hydraulic conductivity reduction from ponded hog manure under these experimental conditions is mainly related to the development of the black layer at the manure-soil interface.
Energy inputs were calculated for grain corn production with data from field experiments utilizing inorganic fertilizer and liquid swine manure as sources of plant nutrients. The calculations utilized energy coefficients taken from the literature and actual application rates of the various input products including seed corn, starter fertilizer and regular inorganic fertilizer, herbicides, fuel for field operations, and grain drying. The results showed that grain corn could be produced successfully by substituting manure for inorganic fertilizer. The energy savings in the manured treatments resulted largely from eliminating the energy in fertilizer manufacture and ranged from 31 to 34% of the energy input for inorganic fertilizer based grain corn production. Published agricultural statistics were used to extrapolate the results to the entire Mixedwood Plains Ecozone which covers the lower Great Lakes and St. Lawrence River Valley regions of Ontario and Quebec. An estimated upper bound of 4.6 PJ (1 petajoule = 10(15) joules) of energy could be saved annually by substituting livestock manure for inorganic fertilizer in the production of the entire acreage of grain corn grown in the ecozone. This estimate is based on the assumptions of availability of sufficient manure, and no credits being given for manure presently being used. Spatial analysis identified South Western Ontario and the Richileau - St. Hyacinthe region of Quebec as the areas where the potential energy savings would be greatest.
Four different sensors were used to estimate mass-flow-rate and moisture on a pull-type forage harvester. The sensors measured feedroll displacement, crop impact force against a hinged plate located above the blower, the frequency drop of a capacitance controlled oscillator near the end of the spout, and the number of light beam interruptions by forage particles in the spout. Tests were conducted in a corn field with a commercial forage harvester modified with the first two sensors (feedroll displacement, impact force), and in the laboratory using a forage blower adapted to a forage harvester spout for the last two sensors (capacitance controlled oscillator, light beam interruption). The capacitance controlled oscillator was also characterized in a static mode in the laboratory with alfalfa acid timothy particles. When testing in a corn field, good correlations were obtained between estimated mass-flow-rate and either the feedroll displacement (R-2 = 94%) or the crop impact force (R-2 = 95%). When testing in the laboratory, the correlation between mass-flow-rate and the oscillator drop was very good (R-2 = 96%) after a correction procedure. The number of light beam interruptions was not well correlated with mass flow (R-2 = 43% for LEDs placed after the capacitor and R-2 = 6% for LEDs placed before the capacitor). During static measures with alfalfa and timothy, the oscillator frequency drop was also related to crop moisture but calibration corrections were required to consider differences between crop species and chop lengths.
McLean. R.K.. Sri Ranjan. R. and Klassen. G. 2000. Spray e~'al)Oration losses frol11 sprinkler irrigation systems. Can. Agric. Engr. 42:001-008. Minimising the loss of w:.Hcr from irrigation systems is impOrlanl for <lchicving water and energy conscrvaliol1. Water is lost during storage. conveyance and field applic:'lIion. In sprinkler irrigation systems. the loss that occurs in rhe field is the largest of the three. The above canopy spray evaporation loss (ACSEL) represents the portioll of the water lhal is lost to the atlllosphere during the timc it tr.lvcls from thc sprinklcr nozzle to thc crop canopy. Thc electrical conductivily (EC) melhod was llsed lodclcrmine the ACSEL from differcllt types of sprinkler irrigation systcms calculated at increasing dislances from the sprinkler nozzles. In this mClhod, the change in solule concentration and consequenl change in EC as Ihe watcr droplets Iravclthrough the air was lIsed to calculate the volume 10SI by evaporation. The travelling gUll irrigation systems showed lhe largest variation in ACSEL. The ACSEL varied depending on whether lhe water droplets travelled into lhe wind or with the wind. Thcreforll. for measuring ACSEL. il is important to place the collectors on eilhcr side of the travelling gun. The wind directjon in relation 10 the average lravel direclion of the gun also affected Ihe uniformity of ACSEL. The ccntre pivol irrigation systems gave Ihe most uniform ACSEL across Ihe different nozzles. Therefore, for centre pivot systems, abollt four 10 six collectors per row is sufficient to delermine ACSEL in lhe field Wilh n precision of ± 0.5%, Afin d'amcliorer la conservation de reau ct de I'cnergie en irrigation. il est ilnport:.mt de minimiser les pertes d'call des systcmes. L'cau esl perdue lors de I'elltreposagc. du transport et de I'application au champ, Pour les systcmes d'irrigation par aspersion, In pcrte d'eau au champ est hi pillS importante des trois. La pcrte d'cau par evaporation au·dessus du fcuillage (ACSEL) represente la partie de r eau qui cst perdue dans r atmosphere au moment ou elle passe de la buse au feuillagc. LI mcthodc de la conductivitc electriquc (EC) fUI utilisee pour detennincr r ACSEL de diffcrents IYpes de systemes d'irrigation par aspersion. a des distances croissantes des buses. Le volume d'c:lu perdu par evaporation fut calculc grflce a la 1l1esure du changement de concentration de la solution. et donc du changc1l1cl1l de conductivilC ciccI rique (EC), des gounes qui se deplacent dans r air. Les plus grandcs variations d' ACSEL ,"urent obscrvccs avec des systemes d'irrigation il canon mobilc. L' ACSEL variail scion que lcs gouttcs se dcplal;aient avcc ou conlrc Ie vcnt. II cst done important. lorsqu'on mcsure rACSEL. de placcr les rccipienls col1C:Clcurs de chaquc cote du canon mobile. La direction du vent par rapport a la direction moycnne de dcplacemcnt du canon cut egalcmentun effet sur !'uniformitc de r ACSEL. Lcs valcurs d' ACSEL de systcmes d'\IT\'batlOIl a pivOI central furcnl Ics plus uniformes. Quatre a six recipients collcctcllrs par rangcc sont dOllc suftisants pour dctenniner rACSEL crun systcll1e d'irrigation:'1 pivot central aunll precision de ±O.5%, INTRODUCTION
Simulation of soil water flow under transient unsaturated conditions is based on Richards' equation. A one-dimensional unsteady state numerical model (NONSAT) was developed, and it incorporated water uptake by plants. The numerical method of lines (NML) was used to solve Richards' equation. The model accuracy was tested by comparing numerical solutions with those of the HYDRUS model which is based bn finite elements, and with field experimental data (pressure head, water content, drainage volume) collected in three undisturbed pan lysimeters cultivated under potatoes over a period of 195 days. Agreement between measured and simulated values was better for NONSAT than for HYDRUS. For the three pan lysimeters, NONSAT showed an average under-estimation of pressure head of about 2.5 cm. For NONSAT, the difference between measured and observed water contents ranged from 0.009 to 0.123 whereas observed and simulated drainage amounts varied, on average, by 0.3 cm, which corresponds to 15% of the average weekly drainage. The daily mass balance error of NONSAT did not exceed 0.01%, however that for HYDRUS varied between -0.01 and -0.11%.
Slaughterhouse wastewater was treated in four 42-L anaerobic sequencing batch reactors (ASBRs) operated at 30 degreesC. Two ASBRs were seeded with anaerobic granular sludge from a milk processing plant (MPP) reactor and two ASBRs received anaerobic non-granulated sludge from a municipal wastewater treatment plant. Influent total chemical oxygen demand (TCOD) ranged from 6908 to 11 500 mg/L, of which approximately 50% were in the form of suspended solids (SS). Total COD was reduced by 90% to 96% at organic loading rates (OLRs) ranging from 2.07 to 4.93 kg m(-3) d(-1) and a hydraulic retention time of 2 days. Soluble COD was reduced by over 95% in most samples. During the start-up period, high concentrations of solids were lost in the effluent, but under steady state operation, at OLRs above 3 kg m(-3) d(-1). biomass retention was adequate and effluent SS averaged 364 mg/L. Reactors seeded with municipal sludge performed slightly better than those containing the MPP sludge, especially during start-up, but differences between the two sludges decreased with time. The biogas contained 75% methane. About 90.5% of the COD removed was methanized and volatile suspended solid (VSS) accumulation (apparent biomass yield plus undegraded solids from the influent) was evaluated at 0.068 kg VSS per kg COD removed. This high degree of methanization indicated that most soluble and suspended organics were degraded during treatment in ASBRs operated at 30 degreesC.
Patel, R.M., Prasher, S.D. and Bonnell, R.B. 2000. Effects of watertable depth, irrigation water salinity, and fertilizer application on root zone salt buildup. Can. Agric. Eng. 42: 111-115. Salt buildup due to irrigation water salinity and fertilizer application was studied in field Iysimeters planted with green peppers (Capsicum annuum).Waterwas applied by subirrigation, and the fertilizers were incorporated at the soil surface. Three subirrigation water salinities, I, 5, and 9 dS/m and two watertable depths, 0.4 and 0.8 m, were used. The soil salinity was determined by first measuring the bulk soil salinity by time domain reflectometry (TDR) and then converting it to soil solution salinity (ECsw)' It was found that the salinity of the subirrigation water affected ECsw in the upper soil profile when the watertable was maintained at 0.4 m depth. The subirrigation water also affected the lower half of the soil profile when the watertable was maintained at 0.8 m depth; however, it did not affect any salt buildup in the upper half. Also, the addition of N, P, and K fertilizers did not contribute to the salt buildup in the soil. Although watertable depth and subirrigation water salinity affected ECsw' they did not affect the green pepper yield. The experiment was conducted using field Iysimeters filled with a sandy soil and covered with a plastic sheet to simulate arid conditions. Therefore, caution should be exercised in extrapolating the results of this study to field conditions and other soils. L'accumulation de sel dans Ie sol due a l'irrigation avec de l'eau saline et aI'utilisation de fertilisants, a ete etudie au champs dans des Iysimetres OU ont ete semes des plants de piment vert (Capsicum annuum). Un systeme d'irrigation souterraine a ete utilize, et les fertilisants ont ete incorpores ala surface du sol. Nous avons teste trois
Yang, C.-C., Prasher, S.O., Landry, J.-A., Perret, J. and Ramaswamy, H.S. 2000. Recognition of weeds with image processing and their use with fuzzy logic for precision farming. Can. Agric. Eng. 42:195200. Herbicide use can be reduced if the spatial distribution of weeds in the field is taken into account. This paper reports the initial stages of development of an image capture/processing system to detect weeds, as well as a fuzzy logic decision-making system to determine where and how much herbicide to apply in an agricultural field. The system used a commercially available digital camera and a personal computer. In the image processing stage, green objects in each image were identified using a greenness method that compared the red, green, and blue (RGB) intensities. The RGB matrix was reduced to a binary form by applying the following criterion: if the green intensity of a pixel was greater than the red and the blue intensities, then the pixel was assigned a value of one; otherwise the pixel was given a value of zero. The resulting binary matrix was used to compute greenness area for weed coverage, and greenness distribution of weeds (weed patch). The values of weed coverage and weed patch were inputs to the fuzzy logic decision-making system, which used the membership functions to control the herbicide application rate at each location. Simulations showed that a graduated fuzzy strategy could potentially reduce herbicide application by 5 to 24%, and that an on/off strategy resulted in an even greater reduction of 15 to 64%.
Feddes, J.J.R., Ouellette, C.A. and Leonard, J.J. 2000. A system for providing protein for pigs in intermediately sized grower/finisher barns. Can. Agric. Eng 42:209-213. Blend feeding attempts to eliminate excesses and deficiencies in dietary protein associated with conventional phase feeding of growing pigs (20 to 110 kg) by meeting their protein requirements on a daily or weekly basis. An increase in carcass lean percentage and a reduction in feed intake and excreted nitrogen are the primary benefits of blend feeding. Blend feeding systems are becoming more common in new facilities, but a simple inexpensive system that is easy to retrofit to existing, intermediate sized grower barns (similar to 800 growing pigs) is still not available. A prototype blend feeding system has been constructed using mechanical weigh drops (proportioning) and staggered dumping into a single flexible coil delivery anger (mixing) in tandem with feed proximity sensors and computer controlled valves (distribution). When an empty feeder is detected, via a feed proximity sensor, a batch of feed mixture is prepared and directed to the correct feeder by computer controlled valves. The required protein concentration in the feed is achieved through one-kg weigh drops of 12 and 20% protein feeds in the proper ratio, i.e. 18% protein = 1:3 ratio. Alternate dumps of the two feeds ensures that adequate mixing occurs in the delivery auger. Five trials were conducted at three different feed ratios: 1:1, 3:1, and 1:9. The 15 blended batches were analyzed for batch size and protein content accuracy and protein content coefficient of variation (CV). The nominal batch size was 40.4 kg and the mean batch size error was 1.47 kg (+/-0.47) or 3.64%. The average batch protein content error was 0.63%. Comparing the economics of this system with a commercially available one for a 800-feeder barn (2000 pigs/year), the cost/pig place is $41.75 and $65.25, respectively, if cost recovery is assumed over one year. If the producer installs the components of the system, the cost/pig place is $28.00.
Mechanical conditioning experiments of hemp were conducted at two growth stages (fibre stage and seed stage) with a forage mower-conditioner consisting of two intermeshing rubber rolls. Conditioned hemp was placed on a mowed lawn in a yard to be naturally dried. Drying rates of hemp were examined by measuring the moisture losses through a three-day drying period at each stage. Drying curves for the two stages showed similar trends. However, a higher drying rate was observed for the hemp at the fibre stage which was initially wetter(71% versus 59% moisture content on wet basis). Four different roll pressures between 0.3 and 6.6 N/mm were used for conditioning. Conditioning was effective in increasing the drying rate of hemp. A roll pressure of 2.4 N/mm appeared most effective for drying at the fibre stage and 4.5 N/mm at the seed stage.
The groundwater quality of five 20 to 35 year old cattle feedlots around Saskatoon were investigated. Water samples were obtained from 30 piezometers (2.5 to 14.5 m deep) during three sample times (February, June, and August of 1997). All piezometers were located outside the feedlot pens but within or adjacent to the feedlot area. The objective of this study was to determine whether shallow groundwater within the feedlot area is contaminated by feedlot manure. Elevated concentrations of the following ions were found to indicate the presence of manure in groundwater; K+, Cl-, NO3-N, NH4-N, and total dissolved P. Due to the absence of baseline data, two different levels of concentration were used: a lower level to divide waters between 'background' and those with perhaps some indication of agricultural activity (i.e. poor fertilizer management); and an upper level to indicate the definite presence of feedlot manure. Of the five sites, four displayed concentrations indicative of feedlot manure. Of the 30 piezometers, only two had low concentrations that could be considered background, that is showing no indication of bring affected by any human activity. The high degree of groundwater contamination as evidenced by the piezometers, could be a function of the shallow levels, only eight piezometers had water levels deeper than 4 m.
Nakano, T., Ikawa, N. and Ozimek, L. 2000. An economical method to extract chondroitin sulphate-peptide from bovine nasal cartilage. Can. Agric. Eng. 42:205-208. Utilization of animal by products by extracting useful material is ofeconomic importance in the livestock industry. This report describes a simple low cost procedure to release chondroitin sulphate (CS) from bovine nasal cartilage without introducing any chemicals except acetic acid used for pH adjustment. More than 70% of total CS in nasal cartilage can be released as CS-peptide by incubation in water at pH 4.5 and 37°C. This is likely the most economical method currently available to extract CS from cartilage. Endogenous proteinases are probably involved in the release ofCS. The extract is boiled and dried at 90°C to obtain a crude CS preparation. The purity of CS can be improved approximately 1.4 fold by anion-exchange chromatography. This information may contribute to the development of a low cost method of preparation of CS for commercial purposes.
