Organic Waste Products Research Articles

Processing pineapple pulp into dietary fibre supplement

Several tonnes of conventionally consumed dietary fibre-containing fruit components are discarded as wastes in the processing of fruits into fruit juices, resulting in the loss of food nutrients and the increased production of organic waste. A study was done to investigate the processing of pineapple pulp waste from a processing plant, into a powdered product to be used as a dietary fibre supplement. The proximate composition and the functional properties of the raw material and final product were determined. The pasting characteristics or properties of wheat flour fortified with the product up to 20 % were also determined using a viscoamylograph. The wheat flour fortified at 10 % level was used to prepare cookies and muffins after which it was subject to a performance test. Proximate analysis of the product showed crude fibre content of about 30 %; crude protein: 8.5 %; crude fat: 1.5 %; total ash: 5.2 %, and ascorbic acid: 20 mg/100 g. The fat and water absorption capacities were 2.5 g/g and 2.0 g/g of product respectively. The foaming and gelation capacities of the product were found to be 2.8 % and 12 %, respectively. Changes in the pasting characteristics of the whole-wheat flour with the 10% level of fortification were not statistically significant. Acceptance levels of the cookies and muffins made from the composite flour were high and much preference was shown for samples from the fortified flour compared to samples from whole-wheat flour without fortification. This study demonstrated a potential way of harnessing pineapple pulp, a dietary fibre source, which is lost in fruit processing. This will improve the economic value to pineapple, which is widely cultivated in Ghana. It also demonstrated a way of increasing the dietary fibre content of some popular foods to help increase the fibre intake and health of the general population.

An Analysis of the Energy Potential of Anaerobic Digestion of Agricultural By-Products and Organic Waste

Anaerobic digestion is a promising option for recycling agricultural by-products and some organic wastes. While both agricultural by-products and wastes have no direct commercial value, their management is both complicated and costly. One option to simplify by-product management and reduce the costs associated with biogas plant feedstock is to substitute dedicated crops with vegetal by-products. Given that the chemical composition of some of these by-products can differ considerably from more typical biogas plant feedstock (such as maize silage), more complete knowledge of these alternatives to produce environmentally friendly energy is warranted. To this end, batch trials under mesophilic conditions were conducted to evaluate the potential biogas yield of many agricultural by-products: maize stalks, rice chaff, wheat straw, kiwi fruit, onions, and two expired organic waste products (dairy and dry bread) from the retail mass-market. Among the considered biomasses, the highest methane producer was the expired dairy product mixture, which yielded 554 lNCH4 kg−1 volatile solids (VS). Maize stalks and wheat straw produced the lowest yields of 214 and 285 lNCH4 kg−1VS, respectively. An assessment of the biogas and methane yields of each biomass was also undertaken to account for the specific chemical composition of each biomass as it can affect the anaerobic digestion operating system. Finally, the total Italian green energy production that might be derived from feeding all these biomasses to a biogas digester was estimated, in order to understand its potential impact.

Effects of fertilization with urban and agricultural organic wastes in a field trial – Waste imprint on soil microbial activity

In the past decades a significant change in composition of urban organic waste products has occurred in many first world countries, due to cleaner technologies as well as outsourcing of heavy industries. However, the societal perception of organic urban waste has become increasingly negative, leading to widespread advocacy of incineration. Therefore we established the ‘CRUCIAL’ long-term field trial in 2003, with the rationale that by approaching the known limits for a number of heavy metals below which no profound disturbance should be observed on key soil ecological functions, it should be possible to discern if some of the many unknown components in the composite urban waste as well as agriculturally based fertilizers have measurable impacts. The following treatments were established: human urine, sewage sludge (normal N-level and accelerated level aiming at three times normal N-level), degassed and subsequently composted organic municipal waste (normal and accelerated level), deep litter, cattle slurry, cattle manure (accelerated level), NPK fertilizer, unfertilized but with clover undersown and an unfertilized control. After 4 years the soil organic matter (SOM) C content, basal CO2 respiration and soil microbial biomass (SMB) C was significantly affected by treatments. All soils having received organic fertilizer had higher SMB C than those with no added fertilizer (unfertilized and unfertilized with clover undersown) and inorganic fertilizer. The treatment effect on qCO2 (CO2/SMB C) was not significant, but the unfertilized treatments showed the highest values. Treatments with accelerated levels of composted household waste and sewage sludge had the highest number of colony forming heterotrophic bacteria. Sole carbon source utilization in EcoPlates indicated a very robust microbial community in the treatments. Cumulative input of heavy metals was less than that required for reaching the heavy metal ecotoxicological limits, even after accelerated loading with sewage sludge corresponding to approximately 55 years of normal application. This could indicate that it is possible use organic urban waste for an extended period on a given site, without compromising soil functioning as long as ecotoxicological guidelines for heavy metal content are observed.

Biological hydrogen production from acid-pretreated straw by simultaneous saccharification and fermentation

Hydrogen is currently produced in large amounts in the chemical industry, including that from the steam reforming of fossil fuels. Hydrogen must be produced sustainably to be economically feasible. This could be achieved from water through electrolysis powered by photosynthetic or other renewable energy, or by gasification or pyrolysis of biomass. It may also be possible to develop a cost-effective and reliable technology to produce hydrogen directly from renewable biomass or organic waste products through anaerobic fermentation. Lignocellulosic biomass contains approximately 70 to 80% carbohydrates. If properly hydrolyzed, these carbohydrates can serve as an ideal feedstock for fermentative hydrogen production. In this research, batch tests of biohydrogen production from acidpretreated wheat straw were conducted to analyze the effects of various associated bioprocesses. The objective of the pretreatment phase was to investigate the effects of various sulfuric acid pretreatments on the conversion of wheat straw to biohydrogen. When sulfuric acid-pretreated solids at a concentration of 2% (w/v) were placed in an oven for 90 min at 120oC, they degraded substantially to fermentative gas. Therefore, wheat that is pretreated under the evaluated conditions is suitable for hydrolysis and fermentation in a batch test apparatus. Different conditions were evaluated in the tests, which were conducted in accordance with standard batch test procedures (DIN 38414 S8): fresh straw, pretreated straw and simultaneous saccharification and fermentation (SSF). The SSF method proved to be the most effective and economical way to convert wheat straw to biohydrogen. The hydrogen yield by this method was 1 mol- H2/mol-glucose, which resulted from 5% carbon degradation (ηC gas) or the equivalent of 64% of the hydrogen volume that was produced in the reference test (glucose equivalent test). This method also proved to have the shortest lag phase for gas production. H2 yields observed in this study are higher than the H2 yields reported in other studies (the use of mixed culture inocula resulted in a slightly higher yield).

Micro-scale quantitation of ten phthalate esters in water samples and cosmetics using capillary liquid chromatography coupled to UV detection: effective strategies to reduce the production of organic waste

We have extracted ten phthalate esters (C1 to C8) using six different micro-scale methods for extraction, and then separated them by capillary liquid chromatography coupled to UV detection. The methods included liquid-liquid extraction, ultrasonic-assisted extraction, microwave-assisted extraction, dispersive liquid-liquidmicroextraction, dispersive liquid-liquid microextraction solidification of floating organic droplets, and cloud point extraction. The linear range of the analytes is from 0.5 to 50 μg mL−1, and the detection limits range from 0.02 to ~0.17 μg mL−1. The precision and accuracy of all intra- and inter-day analyses are <5.5%. We find that dispersive liquid-liquid microextraction solidification of floating organic droplet (DLLME-SFO) is the best method for quantification of most phthalate esters in water samples and cosmetics because of its low limit of detection and high extraction efficiencies.

Applying Composted Cotton Gin Trash to a Vertisol in Southeastern Queensland, Australia

Many Australian cotton farmers are interested in using organic waste products such as composted cotton gin trash as soil amendments because of perceived benefits to soil health and the environment. However, detailed information on the relative benefits and costs involved is not readily available to cotton growers who farm on clayey Vertisols. The objective of this study was to quantify soil changes in a farmer-established trial to evaluate the potential benefits of applying composted cotton gin trash and/or lime to a Vertisol. Selected soil properties were measured in an experiment located on a commercial cotton farm near Goondiwindi in southern Queensland, Australia. Cotton gin trash compost improved potassium availability and soil microbial biomass in soil, whereas lime improved only the latter.

Solid-phase fluorescence spectroscopy to characterize organic wastes

The production of solid organic waste (SOW) such as sewage sludge (SS) or municipal solid waste (MSW) has been continuously increasing in Europe since the beginning of the 1990’. Today, the European Union encourages the stabilization of these wastes using biologic processes such as anaerobic digestion and/or composting to produce bio-energy and organic fertilizers. However, the design and management of such biologic processes require knowledge about the quantity and quality of the organic matter (OM) contained in the SOW. The current methods to characterize SOW are tedious, time-consuming and often insufficiently informative. In this paper, we assess the potential of solid-phase fluorescence (SPF) spectroscopy to quickly provide a relevant characterization of SOW. First, we tested well known model compounds (tryptophan, bovine serum albumin, lignin and humic acid) and biologic matrix ( Escherichia coli) in three dimensional solid-phase fluorescence (3D-SPF) spectroscopy. We recorded fluorescence spectra from proteinaceous samples but we could not record the fluorescence emitted by lignin and humic acid powders. For SOW samples, fluorescence spectra were successfully recorded for MSW and most of its sub-components (foods, cardboard) but impossible for SS, sludge compost (SC) and ligno-cellulosic wastes. Based on visual observations and additional assays, we concluded that the presence of highly light-absorptive chemical structures in such dark-colored samples was responsible for this limitation. For such samples, i.e. lignin, humic acid, SS, SC and ligno-cellulosic wastes, we show that laser induced fluorescence (LIF) spectroscopy enables the acquisition of 2D fluorescence spectra.

High-speed technology for processing organic wastes in bubble type bioreactors

Technology is developed for high-speed preparation of biogas during treatment of organic waste products in bubble type bioreactors. A classification is proposed for existing devices for obtaining biogas. Results are provided for experimental studies of the effect of bubble agitation on the efficiency of obtaining biogas.

Antifungal efficacy of environmentally friendly wood preservatives formulated with enzymatic‐hydrolyzed okara, copper, or boron salts

Okara, an organic waste product obtained from soy milk production, was used with copper chloride or sodium borate to formulate new wood preservatives as a substitute for expensive wood preservatives, such as copper-azole-based preservatives and ammoniacal copper quaternary. Before formulating the preservatives, okara was hydrolyzed by enzymes (cellulase, pectinase, and protease) to augment penetration and fix the biocide salts of the preservatives into wood blocks. The preservatives were injected into wood blocks by vacuum pressure to measure the treatability of the preservatives. The treated wood blocks were placed in hot water for 3 d to measure leachability. The treatability and leachability of the preservatives were affected by the type and loading amount of enzymes and the addition of sodium borate into okara-based wood preservative formulations. The treatability and leachability of the preservatives formulated with copper chloride and okara hydrolysates were 63.38 and 3.15%, and those of the preservatives with copper chloride, okara hydrolysates, and sodium borate were 61.47 and 3.32%, respectively. Despite the hot water leaching, wood blocks treated with preservatives formulated with 2% cellulase, pectinase, and protease hydrolyzed okara, CuCl(2), and sodium borate showed only 1.98% average weight loss against Fomitopsis palustris over 12 weeks. Microscopic observation revealed how okara-based preservatives work in wood blocks. Okara has potential as a raw material for cost-effective and environmentally friendly wood preservatives.

MANAGING GREENHOUSE ORGANIC WASTES: A HOLISTIC APPROACH

During the last decade, several sustainable management practices have been proposed by researchers and extension services. For greenhouse production, three main factors should be considered to reduce environmental burdens: 1) waste management, 2) nutrient emission, and 3) fossil energy use. Organic waste represents a significant source of biomass production for protected crops. Wastes such as 4.5 t tomato leaf biomass ha-1 week-1 are usually discarded in sanitary landfills or directed to other waste management sites such as composting sites or accumulated near the production facility thus constituting a phytosanitary problem. When drainage water from producing greenhouse vegetables is not recycled, nutrient emission into the groundwater may represent a major environmental impact (up to 3000-4500 m3 per ha of tomato wasted nutritive solution containing 4-10 t of nutrients such as nitrogen and phosphorus). Greenhouse culture production also uses a significant quantity of fossil fuel energy, in the form of heat (10-40% of production costs), CO2-enrichment, and fertilizers. Thus, management of significant quantities of organic solid and liquid waste produced by greenhouse crops as well as the use of renewable energy constitute a challenge that can be partly solved by more sustainable production systems. Our integrated closed-loop process recycles both solid and liquid organic waste, and converts the waste into renewable energy (CH4), CO2, and liquid and solid fertilizers. Organic waste products and drained water are then reintroduced into the irrigation system. This ensures minimal risks using biological processes such as anaerobic digestion and nitrifying bioreactor, artificial wetlands and passive bioreactors to reduce nutrient pollutants and sulfate content as well as risks associated to pathogens. The proposed integrated production system uses organic growing media or soil with organic fertilizers as well as liquid organic culture, and constitutes a sustainable organic production system achieving productivity levels as high as conventional growing systems.

Changes in Vertisol properties as affected by organic amendments application rates

AbstractThere is considerable global interest in using recycled organic materials because of perceived benefits to soil health and environment. However, information on the effects of organic waste products and their optimal application rates on the quality of heavy clay soils such as Vertisols is sparse. An incubation experiment was therefore conducted using five organic amendments at various rates to identify their optimal application rates, which could improve the quality of the Vertisol. Cotton gin trash, cattle manure, biosolids (dry weight basis 7.5–120 t/ha), chicken manure (dry weight basis 2.25–36 t/ha) and a liquefied vermicast (60–960 L/ha, volumetric basis) changed the soil chemical, physical and microbiological properties compared with a control where no amendments were applied, viz. higher light fraction of organic matter, nutrient content (N and P) and soil microbial activity. Higher application of chicken manure resulted in an increase in dry‐sieved mean weight diameter. Increasing rates of cattle manure increased exchangeable Na concentration and ESP. Although vermicast itself did not contribute a significant amount of N into the soil, when applied at higher rates (60–960 L/ha), its application resulted in increased concentration of NO3‐N in soil by amounts ranging from 43 to 429%. Optimal application rates for cattle manure and cotton gin trash were 30 t/ha, whereas for biosolids and chicken manure, the optimum rate was 60–18 t/ha, respectively.

Predicting Mineral N Release during Decomposition of Organic Wastes in Soil by Use of the SOILN_NO Model

In order to predict the mineral N release associated with the use of organic waste as fertilizer in agricultural plant production, the adequacy of the SOILN_NO model has been evaluated. The original thought was that the model calibrated to data from simple incubation experiments could predict the mineral N release from organic waste products used as N fertilizer on agricultural land. First, the model was calibrated to mineral N data achieved in a laboratory experiment where different organic wastes were added to soil and incubated at 15°C for 8 weeks. Secondly, the calibrated model was tested by use of NO3 −leaching data from soil columns with barley growing in 4 different soil types, added organic waste and exposed to natural climatic conditions during three growing seasons. The SOILN_NO model reproduced relatively well the NO3 −leaching from some of the soils included in the outdoor experiment, but failed to reproduce others. Use of the calibrated model often induced underestimation of the observed NO3 −leaching. To achieve a satisfactory simulation of the NO3 −leaching, recalibration of the model had to be carried out. Thus, SOILN_NO calibrated to data from simple incubation experiments in the laboratory could not directly be used as a tool to predict the N-leaching following organic waste application in more natural agronomic plant production systems. The results emphasised the need for site- and system-specific data for model calibration before using a model for predictive purposes related to fertilizer N value of organic wastes applied to agricultural land.

Improving the quality of sandy soils of the Batéké plateau (D.R. Congo) by using local geological materials and industrial organic waste products

Improving the quality of sandy soils of the Batéké plateau (D.R. Congo) by using local geological materials and industrial organic waste products

Characteristics of a Novel Water Plasma Torch

Relying on heat generated by plasma arc heating liquid water into steam as a swirl gas, a water plasma torch has the distinctive steam generation structure, which has various applications such as in the treatment of organic waste and hydrogen production for fuel cells in future vehicles. The operational features of the water plasma torch and water phase change process in the discharge chamber are investigated based on the temporal evolution of the voltage and current. The optical emission spectrum measurement shows that the water molecule in the plasma is decomposed into H, OH and O radicals. As the electrodes do not require water-cooling, the thermal efficiency of the torch is very high, which is confirmed by analytical calculation and experimental measurement.

Improving the quality of sandy soils of the Batéké plateau (D.R. Congo) by using local geological materials and industrial organic waste products

Improving the quality of sandy soils of the Batéké plateau (D.R. Congo) by using local geological materials and industrial organic waste products

Factors Affecting Benthic Impacts at Scottish Fish Farms

The factors affecting patterns of benthic [seabed] biology and chemistry around 50 Scottish fish farms were investigated using linear mixed-effects models that account for inherent correlations between observations from the same farm. The abundance of benthic macrofauna and sediment concentrations of organic carbon were both influenced by a significant, albeit weak, interaction between farm size, defined as the maximum weight of fish permitted on site at any one time, and current speed. Above a farm size threshold of between 800 and 1000 t, the magnitude of effects at farms located in areas of elevated current speeds were greater than at equivalent farms located in more quiescent waters. Sediment concentrations of total organic matter were influenced by an interaction between distance and depth, indicating that wind-driven resuspension events may help reduce the accumulation of organic waste at farms located in shallow waters. The analyses presented here demonstrate that the production and subsequent fate of organic waste at fish farms is more complex than is often assumed; in isolation, current speed, water depth, and farr size are not necessarily good predictors of benthic impact.

Short-term effects of organic amendments on properties of a Vertisol

Application of organic waste products as amendments has been proposed as a management option whereby soil quality of Vertisols could be improved. An incubation experiment was, therefore, conducted for 4 weeks under controlled temperature conditions (30 degrees C) to identify those potential organic amendments that might improve the quality of a Vertisol. Twelve organic amendments were investigated: cotton gin trash from three sources, cattle manure from two sources, green waste compost, chicken manure from three sources including a commercial product, biosolids and two commercial liquefied vermicomposts. Except for the biosolids, no other organic amendments had any effect on soil microbial biomass and respiration. Compared with NO3-N levels in the control, there was a 50% decrease in soil amended with 10 t ha(-1) green waste compost (65 microg g(-1)). The three different types of chicken manures increased the NO3-N concentration from 75% (228 microg g(-1)) to 226% (424 microg g(- 1)) over the control. Approximate recovery of P added by the amendment as resin-extractable soil P was 53% for cattle manure and 39% for chicken manure. Application of cattle manure resulted in a 22% increase in soil-exchangeable K over levels found in control. Organic amendments application also resulted in a significant increase in exchangeable Na concentration. Some of the organic wastes, viz. cotton gin trash (10 t ha(-1)), cattle manure (10 t ha(-1)), biosolids (10 t ha(-1)) and composted chicken manure (3 t ha(-1)) have value as a source of nutrients to soil and hence showed potential to improve Vertisol properties.

Changes in Properties of Sodic Australian Vertisols with Application of Organic Waste Products

In Australia, the surface and subsurface soils of the majority of cotton (Gossypium hirsutum L.)‐growing regions are sodic. Application of organic amendments can be an option to stabilize the structure of sodic Vertisols due to their potential positive effect on soil physical properties. An incubation experiment was conducted for 4 wk in a temperature‐controlled (30°C) growth chamber to study the effect of organic amendments on the properties of two Vertisols with different sodicity levels. The exchangeable Na percentages (ESPs) in these Vertisol soils collected from the Australian Cotton Research Institute (ACRI) near Narrabri, New South Wales, and a commercial cotton farm near Dalby, Queensland, were modified such that three different sodicity levels resulted, i.e., nonsodic (ESP &lt; 6), moderately sodic (ESP 6–15), and strongly sodic (ESP &gt; 15). The organic amendments used were cotton gin trash (60 Mg ha−1), cattle manure (60 Mg ha−1), and composted chicken manure (18 Mg ha−1), as well as an unamended control. The organic amendments improved the physical properties of both Vertisols by decreasing clay dispersion. In the Dalby soil, cotton gin trash produced the largest decrease (29%) in the dispersion index over the control at the moderate sodicity level, whereas in the strongly sodic soil, the lowest dispersion index resulted from the application of chicken manure. Nutrient availability (N, P, and K) was also increased significantly at higher sodicity levels for both the ACRI and Dalby soils by using organic amendments. These results indicate that using organic amendments can be beneficial for the amelioration of sodic Vertisols and also to sustain soil quality.

Effect of different nitrogen sources on plant characteristics and yield of common bean ( Phaseolus vulgaris L.)

Wastewater sludge can be used to fertilize crops, especially after vermicomposting (composting with earthworms to reduce pathogens). How wastewater sludge or vermicompost affects bean ( Phaseolus vulgaris L.) growth is still largely unknown. In this study the effect of different forms of N fertilizer on common bean plant characteristics and yield were investigated in a Typic Fragiudepts (sandy loam) soil under greenhouse conditions. Beans were fertilized with wastewater sludge, or wastewater sludge vermicompost, or urea, or grown in unamended soil, while plant characteristics and yield were monitored (the unamended soil had no fertilization). Yields of common bean plants cultivated in unamended soil or soil amended with urea were lower than those cultivated in wastewater sludge-amended soil. Application of vermicompost further improved plant development and increased yield compared with beans cultivated in wastewater amended soil. It was found that application of organic waste products improved growth and yield of bean plants compared to those amended with inorganic fertilizer.

Fermentative hydrogen production by the new marine Pantoea agglomerans isolated from the mangrove sludge

A new fermentative hydrogen-producing bacterium was isolated from mangrove sludge and identified as Pantoea agglomerans using light microscopic examination, Biolog test and 16S rRNA gene sequence analysis. The isolated bacterium, designated as P. agglomerans BH-18, is a new strain that has never been optimized as a potential hydrogen-producing bacterium. In this study, the culture conditions and the hydrogen-producing ability of P. agglomerans BH-18 were examined. The strain was a salt-tolerant facultative anaerobe with the initial optimum pH value at 8.0–9.0 and temperature at 30 °C on cell growth. During fermentation, hydrogen started to evolve when cell growth entered late-exponential phase and was mainly produced in the stationary phase. The strain was able to produce hydrogen over a wide range of initial pH from 5 to 10, with an optimum initial pH of 6. The level of hydrogen production was affected by the initial glucose concentration, and the optimum value was found to be 10 g glucose/l. The maximum hydrogen-producing yield (2246 ml/l) and overall hydrogen production rate (160 ml/l/h) were obtained at an initial glucose concentration of 10 g/l and an initial pH value of 7.2 in marine culture conditions. In particular, the level of hydrogen production was also affected by the salt concentration. Hydrogen production reached a higher level in fresh culture conditions than in marine ones. In marine conditions, hydrogen productivity was 108 ml/l/h at an initial glucose concentration of 20 g/l and pH value of 7.2, whereas, it increased by 27% in fresh conditions. In addition, this strain could produce hydrogen using glucose and many other carbon sources such as fructose, sucrose, sorbitol and so on. As a result, it is possible that P. agglomerans BH-18 is used for biohydrogen production and biological treatment of mariculture wastewater and marine organic waste.