Mixture Of Wood Research Articles

Characterization of gaseous emissions and ashes from the combustion of furniture waste

Gaseous emissions and ash obtained in the combustion of furniture waste have been studied, with particular emphasis on the emissions of hazardous pollutants, such as PCDD/Fs and dl-PCBS. Two different combustion procedures were carried out, one of them in a conventional residential stove (without an automatic control of combustion air and bad mixing of combustion gases with air), and the other in a laboratory-scale reactor (operating under substoichiometric conditions).Three different experiments were carried out in the residential stove, in which the gaseous emissions and ashes obtained were analysed. The fuel burnt out in two of the experiments was furniture wood waste and in one of the experiments, the fuel burnt out was briquettes composed of a mixture of furniture wood with 10wt.% of polyurethane foam. One of the purposes of these experiments was the evaluation of the possible inhibition effect of the higher nitrogen content on the formation of PCDD/Fs. Slight inhibition of the PCDD/F formation was found although, it is noteworthy that the lowest yield of PAHs, volatile and semi-volatile compounds were obtained in the combustion of these briquettes.In all experiments, the emission factors of polychlorinated dibenzo-p-dioxins and dibenzofurans and dioxin-like polychlorinated biphenyls (PCDD/Fs and dl-PCBs) were between 29 and 74ng WHO-TEQ/kg sample burnt, lower than that obtained by other authors in the burning of pine needles and cones.PCDD/Fs and dl-PCBs emissions from furniture wood waste combustion were also analysed in the laboratory scale reactor at 850°C and the results were compared with the values obtained from the combustion of solid wood (untreated wood). The total equivalent toxicity obtained was 21.1ng WHO-TEQ/kg sample for combustion of furniture wood waste, which is low in comparison with those obtained for other waste combustion in similar conditions.In the laboratory scale reactor, PCDFs were the dominant compounds in the profiles of PCDD/Fs, by contrast, in the combustion in the residential stove, the majority compounds were PCDDs, due to the different operation conditions.

Ash Characterization of Four Residual Wood Fuels in a 100 kWth Circulating Fluidized Bed Reactor Including the Use of Kaolin and Halloysite Additives

Solid biomass ash related issues and adequate fuel characterization, especially for fuels with similar thermochemical properties, are still major challenges in combustion. As a consequence, the fuel switching and the valorization of unconventional available fuels are hazardous. An integrated strategy to characterize biomass fuels for ash related issues is applied to four residual woody fuels, namely, a mesquite wood mixture, rubberwood, an invader bush wood, and bamboo wood. The characterization is performed with detailed analyses including (i) ash composition, (ii) ash association forms by leaching, (iii) recently reviewed predictive correlations, (iv) thermochemical equilibrium computations to predict the ash phases formed as a function of the combustion parameters and with the use of a state-of-the-art oxide database, and (v) experimental testing in a 100 kWth circulating fluidized bed pilot reactor (CFB100). The CFB100 testing allowed investigation of the fuel ash cycle including fly ash recirculation, agglomeration and fouling tendencies, and the use of halloysite and kaolin mineral additives. Among the four fuels, bamboo evidenced the higher agglomeration trend, which increased when reducing the additive. With respect to the other fuels, rubberwood seems to have a slightly higher tendency to initiate the coating-induced agglomeration mechanism. Concerning fouling, the mesquite mixture wood is more prone to deposition, mainly because of the formation of Ca-based deposits, while for the other three fuels, ash partitioning shows that the majority of reactive alkali metals fed to the pilot is accumulated in the bottom ash and circulating material. The novel integrated strategy is successfully applied for advanced solid biomass fuel characterization for combustion.

RESISTÊNCIA DE PAINÉIS AGLOMERADOS PRODUZIDOS COM MISTURA DE MADEIRA DE ESPÉCIES FLORESTAIS TRADICIONAIS E NÃO TRADICIONAIS

Este trabalho teve como objetivo avaliar a resistência de painéis aglomerados fabricados com partículas de madeira de Pinus taeda (pinus), Eucalyptus saligna (eucalipto), Mimosa scabrella (bracatinga) e Hovenia dulcis (uva-do-japão) em diferentes proporções de misturas e em duas composições de camadas. Os painéis foram produzidos em misturas de duas, de três e das quatro espécies para painéis monocamada, e nas proporções de duas espécies para painéis multicamadas. Foram também produzidos painéis com madeira de pinus pura. O adesivo usado foi à base de ureia-formaldeído e a massa específica nominal estabelecida foi de 0,65 g/cm³. Foram avaliadas as propriedades físico-mecânicas de massa específica, teor de umidade, flexão estática, ligação interna e arrancamento de parafusos. As análises permitiram avaliar o efeito da utilização da madeira das diferentes espécies em misturas na fabricação dos painéis aglomerados. Os resultados foram também comparados aos requisitos das normas ANSI A 208.1. Verificaram-se aumentos nos valores das propriedades de flexão estática, ligação interna e arrancamento de parafusos com o aumento da proporção de pinus e uva-do-japão e diminuição com aumento da proporção de bracatinga e eucalipto. Portanto, pode-se concluir que as espécies que mais se destacaram foram o pinus e a uva-do-japão. Em relação à composição, os painéis multicamadas, em sua maioria, apresentaram-se superiores aos painéis monocamada.

Comparison of the air-blown bubbling fluidized bed gasification of wood and wood–PET pellets

Air-blown bubbling fluidized bed gasification of wood pellets and wood–PET (polyethylene terephthalate) pellets was conducted at 725°C, 800°C, and 875°C. Gasification of mixtures of wood and PET pellets was attempted; however, rapid formation of coke above the fluidized bed prevented steady state operation of the gasifier. Coking was prevented when wood and PET were formed into composite wood–PET pellets. The performance of wood pellets was better than wood–PET pellets. Tar concentrations were lower, while, heating values, thermal outputs, and efficiencies tended to be higher for wood pellets than wood–PET pellets. The addition of secondary air above the fluidized bed was explored as a means of reducing the tar content of the produced gases. The influence of the produced gas tar concentrations on down-stream tar removal units was considered.

Mitigation of micropollutants for black water application in agriculture via composting of anaerobic sludge

The excess sludge from Up-flow anaerobic sludge bed (UASB) reactor operated on source separated toilet wastewater is a potential source of nutrients and organic matter. It can be further stabilized and dried by composting and applied as a soil amendment. Presence of pathogens, heavy metals and micropollutants in the compost derived from anaerobic sludge is thus undesirable. This paper focuses on removal of micropollutants, typically present in domestic wastewater, via composting of UASB sludge with waste wood. Estrone, diclofenac, ibuprofen, metoprolol, carbamazepine, galaxolide and triclosan were spiked to a mixture of UASB sludge and waste wood. Their concentrations were monitored during 92 days of composting at controlled temperature conditions. All studied micropollutants were removed at various rates with overall removal ranging from 99.9% for ibuprofen, diclofenac and estrone to 87.8% for carbamazepine. Accumulation of methyltriclosan as by-product of triclosan degradation was observed. The prospects and limitations of the integration of a composting process into Source Separated Sanitation concepts are discussed.

Thermal Insulation Particleboards Made with Wastes from Wood and Tire Rubber

The concept of sustainable buildings addresses the environmentally efficiency, with respect to energy consumption, by adopting products that offer thermal insulation. Moreover, use of wastes from different materials also contributes to obtain products for this application. The volume of wastes from timber industry and those from tires are an environmental problem. This study aimed to production and characterization of particleboards using wastes from wood and tire rubber with castor-oil polyurethane resin. Panels were produced containing only wood and also with addition of tire rubber. The properties determined were density, modulus of rupture (MOR) and modulus of elasticity (MOE) in bending, according to Brazilian Code NBR 14810-3 (2006), and thermal conductivity. Statistical analysis was conducted in physical and mechanical properties. Panels containing wood were classified as low density (0.55 g/cm³), while those with wood and tire rubber resulted in medium density (0.78 g/cm³). For mechanical properties, the addition of rubber resulted in increased of MOR and reduction for MOE. Superior performance for thermal conductivity was achieved for panels produced only with wood. However, samples with a mixture of wood and tire rubber also showed consistent thermal conductivity with similar products. Considering the results obtained, panels containing wood and tire rubber addition have potential for application as thermal insulation.

Pyrolysis of lignin with 2DGC quantification of lignin oil: Effect of lignin type, process temperature and ZSM-5 in situ upgrading

Thermal and catalytic pyrolysis of various types of lignin and their influence on the yield and the quality of the produced lignin oil were studied. Lignins originated from a mixture of pine and spruce wood (softwood), a mixture of birch and aspen wood (hardwood) and Eucalyptus Urograndis. High degree of deoxygenation of the bio-oil and maximum yield of value-added chemicals were the main targets of this work. 2DGC-ToFMS analysis was used for the qualitative and quantitative characterization of the lignin oils. Softwood lignin was found to be the most attractive feedstock and high yields of a mixture of phenolic compounds were detected in all cases. High char production was also evident for all types of lignins accounting for almost 50% of the original feedstock. The use of a commercial ZSM-5 catalyst was extremely beneficial for the process, enhancing deoxygenation at higher oil yields compared to thermal pyrolysis. Depending on the nature of the lignin, guaiacyl or syringyl groups were dominant in the oils and it was found that process optimization, involving lignin, catalyst selection and temperature could significantly improve the process efficiency.

Estimation of Filtration Potential of an Effective Biosand Filter for Removal of Iron, Turbidity from Various Sources of Water

A study has been conducted for designing, constructing and evaluating of an effective biosand filter. Different types of charcoal mixture such as bamboo, coconut and wood and carbon mat as an important filter media was used for the modification of biosand filter. The filter had seven layers with gravel, sand, carbon mat and charcoal which were responsible for filtration process. The filtered water analysed in every 20 min interval. The raw ground water pH was 6.12 while it passes through bamboo, coconut and wood mixture filter, the filtered water showed higher pH value. The filter in which mixture of charcoal used as filter media showed better removal efficiency of turbidity compared to control filter without charcoal and mat. The value of turbidity in filtered water of charcoal mixture filter was below 2 NTU which is the permissible limit of drinking water according to World Health Organization but for control it was average 14 NTU. Initially the flow rate was higher and gradually decreases with time. The flow rate of the Biosand filtered water decreases significantly with increase in turbidity. The charcoal based filter showed better removal of iron (II) (95-98%) compared to control (73-76%). The charcoal based filter resulted tastier water by enriching of water with mineral like sodium and potassium.

Fluidized-Bed Gasification of Plastic Waste, Wood, and Their Blends with Coal

The effect of fuel composition on gasification process performance was investigated by performing mass and energy balances on a pre-pilot scale bubbling fluidized bed reactor fed with mixtures of plastic waste, wood, and coal. The fuels containing plastic waste produced less H2, CO, and CO2 and more light hydrocarbons than the fuels including biomass. The lower heating value (LHV) progressively increased from 5.1 to 7.9 MJ/Nm3 when the plastic waste fraction was moved from 0% to 100%. Higher carbonaceous fines production was associated with the fuel containing a large fraction of coal (60%), producing 87.5 g/kgFuel compared to only 1.0 g/kgFuel obtained during the gasification test with just plastic waste. Conversely, plastic waste gasification produced the highest tar yield, 161.9 g/kgFuel, while woody biomass generated only 13.4 g/kgFuel. Wood gasification showed a carbon conversion efficiency (CCE) of 0.93, while the tests with two fuels containing coal showed lowest CCE values (0.78 and 0.70, respectively). Plastic waste and wood gasification presented similar cold gas efficiency (CGE) values (0.75 and 0.76, respectively), while that obtained during the co-gasification tests varied from 0.53 to 0.73.

Caracterización físico-química de pellets producidos a partir de mezclas 50/50 carbón bituminoso/madera residual

Los biocombustibles, demandan procesos de caracterización y transformación confiables que aseguren su adecuado proceso de fabricación para que los usuarios finales los utilicen sin riesgo alguno. Alrededor del 4,42% de los biocombustibles que se comercializan a nivel mundial se presentan como aglomerados o pellets. Teniendo en cuenta que Colombia es un país con altas reservas de carbón y que como país agrícola produce grandes cantidades de residuos orgánicos, se encontró que la mezcla de estos dos productos presenta beneficios desde el punto de vista energético y de combustión, facilitando su quema y disminuyendo emisiones tanto de material particulado como de gases con contenido de azufre. Se presentan los resultados de la caracterización según normas internacionales de pellets producidos en el Laboratorio de Energías Renovables de la Universidad Nacional de Colombia de mezclas 50/50 de carbón antracita y madera. La evaluación fisicoquímica se hizo aplicando parámetros de la norma Austriaca ONORM M7135, con el fin de evaluar cada uno de los ítems allí establecidos. Además, se dan a conocer los resultados de las pruebas y los análisis de la caracterización de estas mezclas, así como su poder calorífico según norma ASTM D5865 11a y su resistencia al impacto según norma ASTM D440-86. Adicionalmente se discuten las ventajas y desventajas desde el punto de vista ambiental que acarrea el uso de los biocombustibles aglomerados.

Production of Renewable Petrochemicals from Catalytic Co-Pyrolysis of Beech Wood and Low-Density Polyethylene with Mesoporous Bifunctional ZSM-5 Zeolites

This study investigated catalytic fast pyrolysis (CFP) of beech wood, low-density polyethylene (LDPE), and their mixture (mass ratio of 1) with a conventional microporous ZSM-5 and mesoporous bifunctional Zn/ZSM-5meso zeolite prepared by desilication of the conventional ZSM-5 with NaOH solution and then impregnation with Zn.The generation of mesopores by desilication improved the diffusion property of the zeolite, which decreased the formation of undesired polyaromatic hydrocarbons from secondary polymerization reactions of monoaromatics in CFP. In addition, the impregnation of Zn increased the dehydrogenation activity of the zeolites, and thus enhanced the conversion of low-value alkanes to valuable olefins. As a result, Zn/ZSM-5meso produced higher yields (56.0 C%) of valuable petrochemicals (monoaromatic hydrocarbons and olefins) and lower yields of undesired polyaromatics (1.70 C%) and alkanes (10.2 C%) in co-feed CFP of the beech wood and LDPE mixture than ZSM-5 (48.2 C%, 4.18 C%, and 18.7 C% for petrochemicals, polyaromatics, and alkanes, respectively).ZSM-5 desilication and impregnation with Zn thus have a beneficial effect on improve the product distribution in CFP of biomass and plastic mixtures. In addition, the results suggest that CFP may provide a promising technology for producing renewable petrochemicals from municipal and agricultural solid wastes, which usually contain high contents of biomass and waste plastics.

Radiocarbon-based determination of biogenic and fossil carbon partitioning in the production of synthetic natural gas

The applicability of the radiocarbon (14C) method for the quantification of the biogenic carbon fractions at different stages of the Synthetic Natural Gas (SNG) production process is demonstrated in this study. The 14C-based biogenic carbon fractions were determined in process flue gas and raw SNG and were 38% and 89% respectively, for a mixture of wood and fossil lignite with 75 ± 3% biogenic carbon as input material. The differences in biogenic carbon fractions between the input material, flue gas and raw SNG are caused by bio-fossil carbon partitioning during the SNG production process. This study demonstrates that the main bio-fossil carbon partitioning took place during the gasification of the input material. This is due to the large differences in volatility and char content of the wood and lignite materials. For the determination, verification or certification of the biogenic carbon fraction in process flue gas and (raw) SNG in the SNG production process, separate investigations of the gases are inevitable. The 14C method is a useful and reliable independent method for these purposes.

Influence of bark on fuel ethanol production from steam-pretreated spruce.

BackgroundBark and bark-containing forest residues have the potential for utilization as raw material for lignocellulosic ethanol production due to their abundance and low cost. However, the different physical properties and chemical composition of bark compared to the conventionally used wood chips may influence the spruce-to-ethanol bioconversion process. This study assesses the impact of bark on the overall bioconversion in two process configurations, separate hydrolysis and fermentation (SHF) and simultaneous saccharification and fermentation (SSF), utilizing steam-pretreated spruce bark and wood mixtures.ResultsMixtures of different proportions of spruce bark and wood chips were subjected to SO2-catalyzed steam pretreatment at 210°C for five minutes, which has been shown to be effective for the pretreatment of spruce wood chips. The final ethanol concentration was the highest without bark and decreased significantly with increasing proportions of bark in both process configurations. However, this decrease cannot be attributed solely to the lower availability of the carbohydrates in mixtures containing bark, as the ethanol yield also decreased, from 85 to 59% in SSF and from 84 to 51% in SHF, as the mass fraction of bark was increased from 0 to 100%.ConclusionsThe results show that it was significantly more difficult to hydrolyse spruce bark to monomeric sugars than wood chips. Bark had an adverse effect on the whole bioconversion process due to its lower enzymatic hydrolyzability. On the other hand, bark inclusion had no detrimental effect on the fermentability of steam-pretreated spruce wood and bark mixtures. It was also observed that lower amounts of inhibitory degradation products were formed during the steam pretreatment of spruce bark than during the steam pretreatment of wood chips.

Thermal Spray Coatings for High-Temperature Corrosion Protection in Biomass Co-Fired Boilers

There are over 1000 biomass boilers and about 500 plants using waste as fuel in Europe, and the numbers are increasing. Many of them encounter serious problems with high-temperature corrosion due to detrimental elements such as chlorides, alkali metals, and heavy metals. By HVOF spraying, it is possible to produce very dense and well-adhered coatings, which can be applied for corrosion protection of heat exchanger surfaces in biomass and waste-to-energy power plant boilers. Four HVOF coatings and one arc sprayed coating were exposed to actual biomass co-fired boiler conditions in superheater area with a probe measurement installation for 5900 h at 550 and 750 °C. The coating materials were Ni-Cr, IN625, Fe-Cr-W-Nb-Mo, and Ni-Cr-Ti. CJS and DJ Hybrid spray guns were used for HVOF spraying to compare the corrosion resistance of Ni-Cr coating structures. Reference materials were ferritic steel T92 and nickel super alloy A263. The circulating fluidized bed boiler burnt a mixture of wood, peat and coal. The coatings showed excellent corrosion resistance at 550 °C compared to the ferritic steel. At higher temperature, NiCr sprayed with CJS had the best corrosion resistance. IN625 was consumed almost completely during the exposure at 750 °C.

Particleboard from wood particles and sycamore leaves: Physico-mechanical properties

The aim of this study was to evaluate the physical and mechanical properties of particleboards manufactured from mixture of sycamore leaves and wood particles. Five panel types were made from mixtures of wood particles/sycamore leave (100/0, 90/10, 80/20, 70/30 and 60/40%, respectively). Some mechanical (modulus of rupture, modulus of elasticity and internal bonding strength) and physical properties (thickness swelling and water absorption) of the particleboards were determined. The results show that with incorporation of sycamore leaves up to 20%, the mechanical and physical properties of resulting particleboards improves. Nevertheless, the mechanical properties of all the panels exceed the minimum requirements of EN Standards for furniture manufacturing. Using renewable bio materials like sycamore leaves for manufacturing particleboards could contribute solution of raw material shortage for particleboard industry, decreasing the pressure on forest resources and diminishing environmental problems regarding their burning.

Colorimetric patterns of wood pellets and their relations with quality and energy parameters

Color of wood pellets is mainly affected by the feedstock material used for their production and which composition and characteristic affect the final product quality. Pellets made from pure wood are light in color and have low ash content, while pellets made from different mixtures of wood and bark or foliage are generally darker and richer in minerals. This study aims to verify the correlation between color and quality parameters of wood pellets available on the Italian market. All the samples were analyzed following the procedures laid down by the European Norms (EN) on solid biofuels for moisture, ash, calorific value, durability, bulk and solid density. The acquisition of the images was done with two techniques: the CIE L∗a∗b∗ color space and RGB-HSV color spaces. Canonical correlation analysis (CCA) was performed with CIE-L∗a∗b, RGB and HSV separately showing for all the color components good degree of correlation with ash content of pellets. The PCA analysis on two principal components (total explained variance: 64.2%) showed a clear color gradient moving form good to medium or low quality parameters. This pattern is confirmed by the clustering of certified pellets in the region of lightest samples. The calculation of ΔE and ΔRGB showed a good discrimination level between whole pellets samples and their sawdust, and between ones with high and low ash content. The visual predictability of pellets quality on the basis of their color is however not so sharp when considering samples with similar colors. The industrial applicability of such methods for the evaluation of pellets quality is desirable for RGB methodologies that are less expensive and more reliable in working condition, given that specific color calibration is performed.

Superheater fouling in a BFB boiler firing wood-based fuel blends

Four different fuel blends have been fired in a 28MWel BFB. Wood pellets (test 0) were not problematic for about ten years, contrary to a mixture of demolition wood, wood cuttings, compost overflow, paper sludge and roadside grass (test 1) which caused excessive fouling at a superheater bundle after already a few weeks. Two week tests with the test 2 blend (wood chips and cuttings, compost overflow and paper sludge) and test 3 blend (wood chips, demolition wood and wood cuttings) showed that, based on air cooled probe tests, fouling was slightly higher with test 3 compared to test 2. The bulk of the deposits consisted of a mixture of CaSO4 and K2SO4 (with minor amounts of Na2SO4). The occurrence of alkali sulfates is explained by a combination of 4 different deposition mechanisms. Gaseous alkali chlorides that condense, either as chlorides or sulfates and form aerosols, that deposit, especially initially, by thermophoresis (1), and, in the more mature deposit, by eddy diffusion and Brownian diffusion (2). The gaseous alkalis can also condense directly on the tube surface or on, or in the deposit (3). Gaseous alkalis can also condense on larger particle surfaces that deposit by inertial impaction (4). Whether gaseous alkalis have sulfatized during transport or after deposition, or both, could not be determined. CaSO4 is formed by sulfation of Ca-containing particles (not being silicates or slag) that cause the deposits to be sintered modestly (tests 2 and 3) or to a large extent (test 1, matured deposit). A molten K–Na–SO4–Cl salt is thermodynamically stable at the temperature range of tube surface +40K to local flue gas temperature, and may also have contributed to sintering when reactive Ca is present locally in only low concentrations. Thermodynamic calculations predict fouling tendency as test 3>test 2>test 1>test 0. The total amount of molten salt seemed a better predictor for fouling than the amount of salt as a percentage of total ash.

Gasification characteristics of sewage sludge combined with wood biomass

The gas products from gasification processes have been considered to have some limitations in gas composition and heating value from the previous studies. Gasification characteristics of sewage sludge and wood mixture were investigated using different mixing ratios with the purpose of better quality of gas product suitable for energy/power generation. The gasification experiment was performed by an indirectly heated fluidized bed reactor. As reaction temperature increased from 600 to 900 °C, the yield of gas product increased with higher generation of CO, H2 and CH4 by more activated gas conversion reactions. As the equivalence ratio increased from 0.2 to 0.4, composition ratio of CO2 increased while CO, CH4, H2 decreased as expected. Several operating variables including mixing ratio of wood with dried sludge were also tested. From this initial stage of experiment, optimal operating conditions for the bubbling fluidized bed gasifier, could be considered 900 °C in temperature; 0.2 in equivalence ratio and 40 % in wood mixing ratio within test variables range. These results will be more thoroughly investigated for the application to the larger scale pilot system.

Influence of walnut shell as filler on mechanical and physical properties of MDF improved by nano-SiO2

The aim of this study was to evaluate some mechanical and physical properties of medium density fiberboards (MDFs) made from various mixtures of wood fibers and walnut shell flour using SiO2 modified urea–formaldehyde resin. Six panel types were made from mixtures of wood fiber/walnut shell flour, 100/0, 90/10, 80/20, 70/30 and 60/40 %, respectively. The incorporation of walnut shell flour greatly improved the water resistance of the panels. However, flexural properties and internal bond strength decreased with increasing walnut shell flour ratio. The results indicated that panels can be manufactured utilizing walnut shell flour up to 10 % without falling below the minimum EN standard requirements of mechanical properties for general purpose MDF panels.

Soil quality recovery and crop yield enhancement by combined application of compost and wood to vegetables grown under plastic tunnels

Vegetable cultivation under plastic tunnels is a steadily growing agricultural sector but concern developed over environmental sustainability of this farming system. Our aim was to identify organic amendments with a biochemical quality that effectively balance the trade-off between organic carbon recovery, in terms of increasing soil organic C stock, and nutrient mineralization. A three-year field experiment was carried out in two farms of southern Italy characterized by plastic tunnel cultivation and contrasting soil characteristics. Two compost–wood mixtures were used, with final C/N ratio of 15 and 25, and supplied in two doses (30 and 60Mgha−1). Vegetable yield was assessed by monitoring 14 cropping cycles, and soil quality by determining 18 soil parameters including chemical and biological properties. Crop yields were significantly higher in amendment plots, compared to unamended control plots under plastic tunnel, for 12 out of 14 cropping cycles. Combined application of compost and wood allowed an effective recovery of soil C content within three years. Soil amendments improved soil biological functions as revealed by a general trend of positive effects on dehydrogenase, phosphatase and β-glucosidase as well as on soil respiration. The higher C/N ratio mixture determined only a short-term restriction of mineral nitrogen availability. Organic amended plots showed a significant increase in soil exchangeable Na+ and electrical conductivity compared with untreated controls. Compost–woody combination can be used to recover soil carbon stock and fertility and, at the same time, to support vegetable production under plastic tunnels. However, the possible increase of soil salinity after compost amendment may negatively affect soil quality in the long-term.