Showing papers on "Sawdust published in 2000"

High-pressure densification of wood residues to form an upgraded fuel

Abstract: High-pressure binderless compaction of wood processing residues and other biomass waste materials, including hardwood, softwood, and bark in the forms of sawdust, mulches, and chips, were studied. A piston-and-mold (punch-and-die) process was used to produce densified logs (slugs) under room temperature and at pressures ranging from 34 to 138 MPa. The properties of the logs including density, abrasion resistance, impact resistance, compressive strength, water resistance, and long-term performance were tested. The effects of moisture content, compaction pressure, compaction speed, pressure holding time, particle size and particle shape were studied. It was found that the necessary moisture for producing good-quality logs ranges from 5 to 12% for all the woody materials studied, and the optimum moisture content is in the neighborhood of 8%. It was also found that mulch is the easiest form to be compacted into dense and strong logs, sawdust is the second, and chips the last. For the mulches, a compaction pressure of 70 MPa can produce high-quality logs. For sawdust, a minimum pressure of 100 MPa is needed to form good logs. And for chips, no good logs can be made even at pressure as high as 138 MPa. The logs produced under optimal conditions had dry densities near or higher than 1 g / cm 3 . Such high density facilitates storage, handling and transportation of biomass. The dense logs also have high-energy content per unit volume, making it easier to be co-fired with coal in power plants.

Pyrolysis of sawdust in a conical spouted‐bed reactor with a HZSM‐5 catalyst

Abstract: The effect was studied of using an in-situ catalyst based on a HZSM-5 zeolite in flash pyrolysis with an inert gas (N{sub 2}) of pinus insignis sawdust in a conical spouted-bed reactor in the 400--500 C range and for a gas residence time of 50 ms. The use of the catalyst increases the yield of gases and decreases the yields of liquid and char. Likewise, the yield of CO{sub 2} decreases, whereas the yield of C{sub 4{minus}} hydrocarbons increases (15.9 wt. % at 450 C). The catalyst is efficient for partial deoxygenation of the liquid product.

Pyrolysis of Sawdust in a Conical Spouted Bed Reactor. Yields and Product Composition

Abstract: The performance of original equipment provided with a conical spouted bed reactor has been studied in flash pyrolysis of sawdust with an inert gas (N2) in the 350−700 °C range and with 50 ms of average gas residence time. The effect of pyrolysis temperature on the yields of gas, liquid, and char on gas and liquid composition and on char properties has been studied. The maximum yield of liquid (corresponding to 70 wt %) is obtained at 450 °C and its composition determined by GC/MS is similar to that reported in the literature for bubbling fluidized beds. Although temperatures above 600 °C are required for the development of the char porous structure, the yield of CO2 obtained under these conditions is unacceptable.

Compost Maturity Assessment Using Calorimetry, Spectroscopy and Chemical Analysis

Abstract: This work is aimed at characterizing compost maturity and, organic matter transformation during this process, by the use of nondestructive spectroscopic and thermal techniques, together with some chemical analysis. Composting was conducted in a laboratory over a period of one year using the organic fraction of domestic wastes, fresh farmyard manure, spent coffee and sawdust as the raw materials. Samples were retired after different periods of composting and were analyzed by differential scanning calorimetry (DSC) and fourier transform infrared (FTIR) spectroscopy as well as by routine chemical parameters including temperature, pH, C/N, ash content and humic-like substances content. Results showed that in case of domestic wastes, spent coffee and farmyard manure, the C/N ratios, ash and humic acid content showed a typical high rate of change during the first 197 days of composting and tended to stabilize thereafter, probably as a result of the maturity of the produced composts. In contrast, sawdust underwe...

Characteristics of some biomass briquettes prepared under modest die pressures

Abstract: Biomass material, including sawdust, rice husks, peanut shells, coconut fibres and palm fruit fibres, was densified into briquettes at modest pressures of 5–7 MPa using a piston and die type of press. The briquettes were tested to evaluate their relaxation behaviour, mechanical strength and burning characteristics. The sawdust briquettes were found to have better overall handling characteristics. But briquettes of different biomass materials required different optimum conditions of fabrication and generally showed a promising potential for further development.

Electrodialytic Removal of Cu, Cr, and As from Chromated Copper Arsenate-Treated Timber Waste

Abstract: Waste of wood treated with chromated copper arsenate (CCA) is expected to increase in volume over the next decades. Alternative disposal options to landfilling are becoming more attractive to study, especially those that promote reuse. The authors have studied the electrodialytic removal of Cu, Cr, and As from CCA-treated timber waste. The method uses a low-level direct current as the “cleaning agent”, combining the electrokinetic movement of ions in the matrix with the principle of electrodialysis. The technique was tested in four experiments using a laboratory cell on sawdust of an out-of-service CCA-treated Pinus pinaster Ait. pole. The duration of all the experiments was 30 days, and the current density was kept constant at 0.2 mA/cm2. The experiments differ because in one the sawdust was saturated with water (experiment 1) and in the rest it was saturated with oxalic acid, 2.5, 5, and 7.5% (w/w), respectively, in experiments 2−4. The highest removal rates obtained were 93% of Cu, 95% of Cr, and 99% o...

Carbon Addition as a Countermeasure Against Biological Invasion by Plants

Abstract: Increased nitrogen availability is known to favor invasion by non-native plants into natural grasslands This suggests that decreasing nitrogen availability might serve as a countermeasure against invasion One way to at least temporarily decrease nitrogen availability to plants is to increase microbial nitrogen uptake by adding carbon to the soil, and sawdust is a carbon source whose low cost could make it a practical conservation tool To test whether adding sawdust to soil can counter the tendency of nitrogen enrichment to promote invasions by non-native plants, we hand-tilled 15 kg sawdust/m2 into the upper soil of the bare, nitrogen-rich patches left by dead shrubs of the nitrogen-fixing shrub Lupinus arboreus in two nearby areas with contrasting levels of invasion in a coastal grassland in northern California After two years, in both areas, patches with sawdust had 40% less biomass of non-native plants than patches without sawdust, whereas biomass of native plants was not affected by sawdust addition The more negative effect of sawdust on non-native species was specifically due to an effect on non-native grasses; adding sawdust increased the frequency of both native and non-native forbs Results suggest that adding carbon as sawdust to soil can help counter invasion of grassland by non-native plants when invasion is being promoted by increased nitrogen availability, especially when the major invasive species are grasses

Immobilization of soil nitrogen as a possible method for the restoration of sandy grassland

Abstract: . Experiments were designed to test the applicability of nitrogen immobilization as a means of accelerating the recovery of an endemic open sandy grassland (Festucetum vaginatae danubiale) on old fields in the Great Hungarian Plain. Effects of various carbon sources (sucrose, starch, cellulose and sawdust) and their combinations in different quantities were studied in laboratory microcosms. Carbon addition decreased nitrogen availability in all cases, the intensity and timing of change being dependent on the type of carbon source applied. The combination of 2 g each of sucrose and polysaccharides (starch, cellulose, sawdust) per kg soil was found to be the most effective, as sucrose decreased available nitrogen content of soil intensively and the polysaccharides maintained the immobilized nitrogen for a longer period. In a follow-up experiment, sucrose and sawdust were selected for field application to test their effectiveness in immobilizing N and accelerating restoration. The field experiment was established to test the importance of abiotic site differences in the immobilization of soil nitrogen. Selected sites were located along an elevation, moisture and productivity gradient. Soil organic matter, microbial biomass-C and decomposition rate varied between sites depending on the elevation gradient. At two sites with lower soil moisture and organic matter levels carbon addition increased microbial activity and nitrogen immobilization significantly.

Effect of maleic anhydride treatment on steam and water absorption of wood polymer composites prepared from wheat straw, cane bagasse, and teak wood sawdust using Novolac as matrix

Abstract: Wheat straw, cane bagasse, and teak sawdust (agrowaste) were sieved up to a 425-μm mesh size and employed for sheet preparation with and without maleic anhydride (MA) treatment using Novolac resin in a 50 : 50 (w/w) ratio. The shore D hardness of MA treated and untreated wood polymer composites (WPCs) was measured. The MA treated WPCs showed 2–3 times more hardness than that of the untreated respective WPCs. Moisture absorption had a detrimental effect on the mechanical properties of the WPCs. MA treatment restricted swelling and water and steam absorption in the agrowaste. Teak sawdust showed the best results in all respects among the three WPCs. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 2963–2967, 2000

Collapse behaviour of plastic tubes filled with wood sawdust

Abstract: The influence of foam-like wood filler on the mode of collapse and energy absorption performance of polyvinylchloride (PVC) tubes has been investigated under quasi-static loading conditions. The mode of collapse of axially crushed PVC tubes has been found to revert from regular three-lobe diamond mode to axisymmetric concertina mode at a certain wood-filling density. The energy absorption capacity of the PVC tubes is enhanced by wood compression as well as by extra stretching in the tube circumference due to shifting from multi-lobe to axisymmetric mode. The collapse of the PVC tubes has been analyzed considering multi-lobe mode, concertina mode and mixed mode. In these models, the interaction of the wood sawdust filler on the final mode of collapse of the PVC tubes has been incorporated. The mean crushing load of the PVC tubes collapsing into the mixed mode is considered as the average mean of that of the concertina mode, the multi-lobe mode and that causing crushing of wood sawdust. Compression tests on wood sawdust were used to extract its mechanical properties and the results have been used in the validation of the analytical model. The analytical results obtained for the mean crushing load agree reasonably well with those from experimental observations.

Differential Scanning Calorimetric Analysis of Composted Materials From Different Sources

Abstract: Differential scanning calorimetry (DSC) was applied to the study of material composted from sawdust, used coffee, farmyard manure and the organic fraction of domestic solid waste. Composting trials were carried out in Morocco and samples were collected after different periods of composting. The results obtained provided evidence that sawdust substrate is not a suitable source for composting due to the high content of lignin; samples from used coffee are characterized by a degree of aromaticity that is lower and a functional group heterogeneity that is higher than those of organic wastes from manure and the organic fraction of domestic wastes. The latter organic waste substrates appear to be easily degraded and humified and to give DSC curves that at the end of composting are vary close to those of native soil humic acids.

Effects of humic substances from composted or chemically decomposed poplar sawdust on mineral nutrition of ryegrass

Abstract: Two organic fertilizers were prepared from the same initial mixture of poplar sawdust, blood and flour either by composting in a reactor or by chemical oxidation. Both processes resulted in loss of c. 30% of the organic matter. Composting required 90 days in comparison to only a few hours with chemical oxidation. Extraction of the organic residues with 1 N KOH gave solutions containing 24·6 and 15·1 g/l of humic substances respectively. These humic solutions were applied to pot-grown Lolium multiflorum Lam. at 4 and 10 mg carbon per pot to assess the short-term uptake of macro and microelements by the plants. When the plants were short of phosphorus, the humic substances from the chemically decomposed sawdust supplied at 10 mg C per pot improved total P uptake and yield. Humic substances also increased copper and manganese uptake, and by enhancing root development, also improved nitrogen uptake and biomass yield.

Char‐formation kinetics in the pyrolysis of sawdust in a conical spouted bed reactor

Abstract: Both the generation of a microporous structure and char formation kinetics have been studied in the pyrolysis of sawdust of Pinus insignis in a conical spouted bed reactor, in the range 350-700°C. The BET surface area (representative of the physical evolution of the solid) and the C/H ratio of the solid (representative of the chemical structural change) have been taken as conversion indices. From the measurement of the C/H ratio of the solid (the more significant variable), it has been determined that the reaction order is 0.5 and that the kinetic constant is between 0.18 min -1 at 350°C and 1.26 min -1 at 700°C. However the value of the constant is almost independent of temperature, at 1 min -1 in the range 500-700°C.

Influence of wood species on the sawdust-based cultivation of Pleurotus abalonus and Pleurotus eryngii

Abstract: Mycelial growth and fruit body formation ofPleurotus abalonus andP. eryngii cultured on various sawdust-based substrates from different wood species were investigated. Growth onCryptomeria japonica substrate resulted in good mycelial growth and a high yield of fruit bodies.Larix kaempferi substrate was unsuitable for the cultivation of these mushrooms. The fruit body formation rate correlated with mycelial growth from all the wood species tested. Although differences were found for mycelial growth and fruit body formation on various wood species, there were no wood species that were completely unsuitable exceptL. kaempferi. These results show that a wide range of wood species can be used for the cultivation ofP. abalonus andP. eryngii.

Batch vibrating fluid bed dryer for sawdust particles: experimental results

Abstract: In a batch experimental equipment, the behavior of a sawdust dryer in a vibrating fluidized bed is analyzed Empirical data concerning fluidization velocities, pressure drops and drying kinetics was obtained, and advantages of using vibration in the drying chamber, relative to a conventional fluidized bed, are shown This technique is presented as an alternative to solve problems of solid agglomeration and bed defluidization Results show that it is possible to dry sawdust with more than 2 kg/kg moisture, in a vibrating bed keeping a high degree of bed homogeneity and high quality of fluidized state

Oxidation of spruce wood sawdust by MnO2 plus oxalate : A biochemical investigation

Abstract: This paper reports the modification/degradation of lignin within spruce sawdust by manganese complexes formed by the association of MnO2 and oxalate. The Mn oxidants formed are shown to modify both the chemical and physical properties of the wood cell wall. Scanning electron microscopy analysis of oxidized tracheids revealed a smoothing of the cell wall surface from the lumen side due to the removal of some material. Thioacidolysis analysis of the oxidized lignin showed reductions of up to 30% in the recovery of ether-linked guaiacyl monomers and up to 45% for the some dimers composing the polymer. The MnO2/oxalate system also slightly modified polysaccharides, corresponding to a 10% loss in weight of arabinose and glucose in the oxidized sample. However, no delignification occurred, according to the acid insoluble lignin content of spruce. Oxalic acid at pH 2.5 did not induce detectable changes in the chemical structures of the lignin or of the polysaccharides. Keywords: Manganese dioxide; oxalate; abiot...

Treatment of swine wastewater using organic filters

Abstract: The primary treatment of swine wastewater can be done by filtration. To this end, the study of alternative materials as a filter media is necessary. With this objective, rice husk, coffee straw, sugarcane trash, triturated corncob, wood sawdust and fine vegetable coal were used as media, conditioned in PVC tubes of 100 mm in diameter and 500 mm in height. The filtering system was maintained under saturated flow conditions. Little or no change was detected in the concentration of N-total, Ca, Mg and Zn in the effluent of the filter, although the concentration of P-total and K increased in the effluents of the filters of rice husk, coffee straw, triturate corncob, reaching a maximum removal efficiency of 43.6%. Removal efficiencies of sedimentable solids higher than 90.0% were obtained in all materials employed as a filtration media, although total solids removal efficiency was less than 33.0%.

Removal of pollutants from water using untreated and treated sawdust and water hyacinth

Abstract: Sawdust and water hyacinth are waste products which have no economical application in Egypt. They even constitute a solid waste as far as the environment is concerned. As-received sawdust and water hyacinth were treated with phosphoric acid, phosphoric acid + urea or phosphoric acid + urea + dimethylformamide. The as-received and treated samples were used for the removal of Methylene Blue, iodine, phenol and ammonia from their aqueous solutions. The optimum conditions for the maximum adsorption of each pollutant were determined. The isotherms obtained obeyed the Freundlich and Langmuir equations in a satisfactory manner. The initial stages of adsorption follow first-order kinetics as predicted from the Lagergren equation. Sawdust and water hyacinth show promising potentialities for the removal of pollutants from water and can, at least, be used as precursors for the preparation of efficient adsorbents for the removal of pollutants from water.

Preparation of wood with thermoplastic properties: Part 2. Simplified technologies.

Abstract: Aspen wood (Populus tremula) as sawdust was chemically modified through a two-step procedure : esterification with maleic anhydride and subsequent oligoesterification with glycidyl methacrylate and maleic anhydride. Simplified techniques consisting of impregnation by immersion followed by thermal treatment using conventional or microwave heating were employed. Chemical analyses and infra-red spectroscopy showed some differences in the chemical composition and structure of the resulting oligoesterified wood depending on the synthesis technique. However, the thermoplastic properties, clearly revealed by thermomechanical analysis, were quite similar and comparable to those exhibited by the oligoesterified wood resulting via classical synthesis. Moreover, similar degrees of chemical modification were obtained for a significantly shorter duration of the process when microwave heating was employed instead of conventional heating.

Pneumatic conveying of wood powder by using a steam-jet ejector

Abstract: Wood powder and sawdust are two fuels which will be tested in a pressurized cyclone-gasifier. The gasifier will be a part of combined cycle power plant where a gas turbine is run by the product gases from the gasifier and a steam boiler will use the exhaust gas from the turbine. To inject the fuel into the cyclone, a steam-jet ejector seems to be appropriate due to its simplicity and the possibility of using the steam produced by the boiler for feeding of the fuel. Three types of wood powder with different particle-size distribution have been tested in different ejector geometries. The results show that the steam-jet ejector is suitable as a feeding pump for wood powder and sawdust. For commercial wood powder fuel with particle size below 1 mm, a powder to steam mass flow ratio of about 25 and with coarser sawdust a mass flow ratio of at least 10 can be reached. The pressure gain required to overcome the pressure drop in the cyclone gasifier can be achieved. The relative pressure gain seems to be independent of the size distribution of the particles.

Briquettability of lignite and woody wastes composite fuel

Abstract: Woody wastes have favorable burning characteristics compared to lignite, as well as low ash content and reduced smoke emission. The aim of this study was to blend lignite with woody wastes to obtain a solid fuel that retains the advantageous characteristics of woody materials. Blends with lignite were made up with 7, 9, 12, 15, and 20% of waste and then briquetted under pressures of 400, 550, 700, and 800 MPa. Sunflower shell, sawdust, and paper mill wastes were used in different amounts with molasses as binder. Studies were carried out on a laboratory scale to determine optimum parameters for briquetting, such as moisture content of lignite and pressure. Briquetting of lignite without waste materials produces products of low strength. The strongest briquettes were obtained with waste contents of 12--20% and lignite moisture contents of 10--12% at briquetting pressures of 550, 700, and 800 MPa. Briquettes with adequate mechanical strength are obtained from lignite-waste blends with the addition of 8% molasses.

Liquefaction of the Used Creosote-Treated Wood in the Presence of Phenol and Its Application to Phenolic Resin

Abstract: A limited initial study was made to evaluate liquefaction of creosote-treated southern pine wood sawdust with liquefaction of birch wood powder as a control. The objective was to assess the feasibility of using creo_.._. sot&treated southern pine wood as a raw material for the-formulation-of-phenol-basedresmadhesives-Them liquefaction was conducted in the presence of phenol with sulfuric acid as a catalyst at reaction temperature and time of 150°C and 60 minutes, respectively. Novolac and resole resins were formulated from the liquefied wood, and their physical and mechanical properties of molding compounds made with them were determined. Residues obtained from samples of liquefied creosote-treated wood (5.8%) were significantly lower than those from non-treated birch wood powder (17.3%). Apparently, the residual creosote content of the treated-wood behaved as a reagent co:working with phenol to enhance the liquefaction. The flexural strength and the flexural modulus of moldings made from novolac.resins prepared from liquefied creosotetreated wood were comparable to novolacs made from non-treated birch wood. Bond quality of southern pine plywood made from liquefied creosote-treated wood resin was only slightly lower than plywood made from conventional phenolic resin. Visual examination of the wood failure on broken shear specimens seemed to indicate overpenetration of the resin made from liquefied creosote-treated wood, and it was probably one of the major causes of lower bond quality. Nevertheless, the first attempt to formulate a phenol-based adhesive made from liquefied creosote-treated wood produced encouraging results. With additional studies. of resole formation and glue mix formulations, it is anticipated that a resin adhesive from liquefied creosote-treated wood with improved bond quality can be developed. Introduction ‘Preservative-treated wood products are well known to significantly prolong their service life and thus extend the forest resource and enhance its sustainability. hxvitably however, treated products become unserviceable either due to mechanical damage or failure, biological deterioration, or obsolescence. Disposal of spent preserved wood increasingly has become a major concern because of its residual preservative content. Popular waste disposal options for spent preserved wood, such as combustion and land filling, arebecxmring more and more costly because of increasingly strict regula: tory requirements. Thus, recycling options, particularly the one requiring zero discharge of preservative into waste streams, are of great importance to those concerned with the life cycle management of treated wood. Research in Pineville, Louisiana, laboratory of Southern Research Station has been focused on the development of a closed-loop recycling system (Pig. 1) with recycled composite products and liquefaction as the two key elements in the system. Three major steps toward determining the :echnological practicability of fabricating composite poles from used utility poles were accomplished with the determination of the residual preservative and its distribution (9), evaluation of the effects of residual preservatives on &ability (11) and decay resistance (12), and recycling of out-of-service utility poles for useful engineered wood products (10). This study, however, is the first in a series of studies on the liquefaction of preservative-treated wood. Despite Session 3B: Advances in Wood Adhesive Formulations l 259 recent advancements in techniques of liquefying wood under mild conditions (6,7,13) and its promising potential for turning by-product wood wastes into new products (1,5,6,8,14,15), no study of liquefying preservative-treated wood has been reported. This study covers the evaluation of the liquefaction of two types of preservative-treated wood (i.e., chromated copper arsenate or creosote) using two liquefaction processes (i.e., in the presence of phenol and alcohols). The objective of the study is to develop an economically viable liquefaction process to either convert treated wood waste into useful products or to develop a novel new technique for the separation of residual preservatives from wood. The results of a preliminary study of liquefying recycled southern pine creosote-treated wood are presented in this papen lkxperimental Procedure Materials The recycled creosote-treated southern pine wood sample used in this study was the sawdust collected from sawing of recycled utility poles in a previous study (9). The sawdust, screened through No. 10 sieve (9 mesh), was used without further treatment. Wood meals used in the liquefaction as a comparison were of 20 to 80 mesh size prepared from the birch chips (Bet&u mrudmomawicti Regel). The filler used in the moldings of the phenolic resin was wood powder of 200-mesh pass size. All the other chemicals were of reagent grade and were used as received. Liquefaction of Creosote-‘Ikeated Wood Liquefaction Procedure.-Liquefaction reaction of the recycled creosote-treated wood was conducted as shown in Figure 2. XI prepare liquefied wood, all used creosote-treated wood, phenol, and sulfuric acid (as a catalyst) were placed in a 300 ml three-branch flask equipped with a stirring system and a reflux condenser. To initiate the reaction, the mixture was heated in an oil bath maintained at 150°C. After the desired reaction time, the liquefied product was cooled to room temperature, and then diluted by methanol, followed by the filtration through a Tayo GA1 00 glass filter paper The resulting filtrate was adjusted to a desired volume and Figure l.-Closed-loop recycling system for preservative-treated wood.

Role of construction debris in release of copper, chromium, and arsenic from treated wood structures.

Abstract: Recent research on the release of wood preservatives from treated wood used in sensitive environments has not considered the potential contribution from construction residues. This study sought to develop leaching rate data for small construction debris and compare those to the release rate from treated wood itself. Western hemlock boards were pressure treated with chromated copper arsenate Type C (CCA-C), and then common construction tools were used to generate sawdust or shavings from those boards. These wood particles were then leached in deionized water, and the leaching rate was compared with that of solid wood samples cut from the same specimen. Release rate data from this study were also compared with those from endmatched samples that were leached in artificial rain in an earlier study. The release rates of copper, chromium, and arsenic from CCA-C treated chain saw sawdust, circular saw sawdust, and spade bit shavings were many times higher than from solid wood when samples were immersed in water. There was little difference in the release rates among the three types of shavings and sawdust, despite differences in their particle sizes. The rates of release from decking exposed to rainfall were many times lower than that of construction debris or solid wood continually immersed in water. These results show the importance of minimizing the amount of construction debris that is allowed to enter the aquatic environment. However, example calculations also demonstrate that if reasonable efforts are made to minimize release of construction debris, the contribution of these particles to the overall release of preservative from the structure will be minimal.

Preparation of Wood with Thermoplastic Properties, Part 1. Classical Synthesis

Abstract: Aspen wood (Populus tremula) as sawdust was chemically modified through a two-step procedure : esterification with maleic anhydride and subsequent oligoesterification with glycidyl methacrylate and maleic anhydride. Chemical analyses and infra-red spectroscopy revealed the differences in the chemical composition and structure of wood as a result of this treatment. These changes were also reflected by a hygroscopicity test and thermal analyses such as thermogravimetry and thermomechanical analysis. The esterified wood showed an increased hygroscopicity and a decreased thermal stability compared to unmodified wood. In contrast, the oligoesterified wood demonstrated a reduced hygroscopicity and a comparable thermal stability up to about 200°C. The thermomechanical analysis of oligoesterified wood clearly showed a significant softening phenomenon in the range 80-140°C, a direct evidence of the thermoplastic properties gained by this chemical modification.

Culture soil modifier and culture soil modified therewith

Abstract: PROBLEM TO BE SOLVED: To obtain the subject modifier having no adverse effect on plant growth on the culture soil modified therewith and capable of improving the biodegradability of the above soil, and to obtain modified culture soil by treating culture soil afforded from coconut palm dust, beaten bark or sawdust or the like with the above modifier. SOLUTION: This culture soil modifier comprises at least one kind selected from iron salts and aluminum salts. The other objective modified culture soil is obtained by treating culture soil with the above modifier; wherein the culture soil is pref. coconut palm dust, beaten bark or sawdust, and the amount of the modifier to be used is pref. 0.1-5 g based on 100 g of culture soil on a dry basis.

Water vapour emission and nitrogen balance from a sawdust deep litter system for weaned pigs.

Abstract: Water vapour emission and nitrogen balance from a sawdust deep litter system for weaned pigs. Five batches of a total of 180 weaned pigs were reared successively in an experimen- tal room on 30 cm deep litter without cleaning between the batches. The litter was a mixture of saw- dust from coniferous and beech trees. Water was added to the litter every 10 days to lower the dust concentration in the room. The total amounts of sawdust and water used were respectively 21.3 kg per pig and 10.2 l per pig. The mean temperature of the litter at 20 cm depth recorded during each of the 5 periods varied from 32.5 °C to 41.8 °C. The average liveweight of the pigs at the begin- ning and at the end of the post-weaning period was respectively 7.9 ± 1.2 kg and 24.5 ± 4.2 kg. The average daily gain was 392 ± 87 g. The temperature and the relative humidity of the air inside and out- side the experimental room and the ventilation rate were continuously recorded in order to calculate the water vapour emission for each batch. The amount of water vapour produced was significantly cor- related to the water consumption of the pigs and reached an average of 1 732 g per pig per day. This amount is 36% greater than the reference used for pigs on slatted floors. This value may be used as a reference to calculate the minimum ventilation rate for piggeries with pigs on sawdust deep litters. The amount of compost produced was 19.9 kg per pig with a dry matter content of 44.7%. The amount of nitrogen in the compost was 231 g per pig which is about 50% lower than the reference used for the slurry. The volatile nitrogen emissions are thus much higher from composts than from slur- ries. deep litter / sawdust / weaned pig / water vapour / nitrogen