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AbstractBACKGROUND: Inappropriate utilisation of biosolids may adversely impact agrosystem productivity. Here, we address the response of wheat (Triticum durum) to different doses (0, 40, 100, 200 and 300 t ha−1) of either municipal solid waste (MSW) compost or sewage sludge in a greenhouse pot experiment. Plant growth, heavy metal uptake, and antioxidant activity were considered.RESULTS: Biomass production of treated plants was significantly enhanced at 40 t ha−1 and 100 t ha−1 of MSW compost (+48% and +78% relative to the control, respectively). At the same doses of sewage sludge, the increase was only 18%. Higher doses of both biosolids restricted significantly the plant growth, in concomitance with the significant accumulation of heavy metals (Ni2+, Pb2+, Cu2+ and Zn2+), especially in leaves. Leaf activities of antioxidant enzymes (ascorbate peroxidase, glutathione reductase, catalase and superoxide dismutase) were unchanged at 40 t ha−1 MSW compost or sewage sludge, but were significantly stimulated at higher doses (200–300 t ha−1), together with higher leaf concentration of reduced glutathione.CONCLUSION: This preliminary study suggests that a MSW supply at moderate doses (100 t ha−1) could be highly beneficial for wheat productivity. Copyright © 2010 Society of Chemical Industry

Abstract Anaerobic digestion of animal by-products was investigated in batch and semi-continuously fed, reactor experiments at 55 °C and for some experiments also at 37 °C. Separate or mixed by-products from pigs were tested. The methane potential measured by batch assays for meat- and bone flour, fat, blood, hair, meat, ribs, raw waste were: 225, 497, 487, 561, 582, 575, 359, 619 dm 3 kg −1 respectively, corresponding to 50–100% of the calculated theoretical methane potential. Dilution of the by-products had a positive effect on the specific methane yield with the highest dilutions giving the best results. High concentrations of long-chain fatty acids and ammonia in the by-products were found to inhibit the biogas process at concentrations higher than 5 g lipids dm −3 and 7 g N dm −3 respectively. Pretreatment (pasteurization: 70 °C, sterilization: 133 °C, and alkali hydrolysis (NaOH) had no effect on achieved methane yields. Mesophilic digestion was more stable than thermophilic digestion, and higher methane yield was noticed at high waste concentrations. The lower yield at thermophilic temperature and high waste concentration was due to ammonia inhibition. Co-digestion of 5% pork by-products mixed with pig manure at 37 °C showed 40% higher methane production compared to digestion of manure alone.

Cassava pulp is a major by-product produced in a cassava starch factory, containing 50–60% of starch (dry basis). Therefore, in this study we are considering its potential as a raw material substrate for the production of methane. To ensure sufficient amounts of nutrients for the anaerobic digestion process, the potential of co-digestion of cassava pulp (CP) with pig manure (PM) was further examined. The effect of the co-substrate mixture ratio was carried out in a semi-continuously fed stirred tank reactor (CSTR) operated under mesophilic condition (37 °C) and at a constant OLR of 3.5 kg VS m−3 d−1 and a HRT of 15 days. The results showed that co-digestion resulted in higher methane production and reduction of volatile solids (VS) but lower buffering capacity. Compared to the digestion of PM alone, the specific methane yield increased 41% higher when co-digested with CP in concentrations up to 60% of the incoming VS. This was probably due to an increase in available easily degradable carbohydrates as the CP ratio in feedstock increased. The highest methane yield and VS removal of 306 mL g−1 VSadded and 61%, respectively, were achieved with good process stability (VFA:Alkalinity ratio < 0.1) when CP accounted for 60% of the feedstock VS. A further increase of CP of the feedstock led to a decrease in methane yield and solid reductions. This appeared to be caused by an extremely high C:N ratio of the feedstock resulting in a deficiency of ammonium nitrogen for microbial growth and buffering capacity.

A seawater spray scrubber was set up and tested with focus to desulfurization of marine engine exhaust gas. Experimental tests were carried out simulating typical exhaust conditions of a marine diesel engine burning heavy fuel oil and using real seawater. Different flue gas flow rates, seawater flow rates, and SO2 concentrations were tested. Liquid‐to‐gas ratios were in the range 1–10 × 10−3. A comparison between seawater and distilled water was also carried out to elucidate the effect of seawater alkalinity. In all conditions, the liquid phase was analyzed for alkalinity, pH, and sulfate content before and after the tests. Finally, the spray droplet size distribution was measured as a function of liquid flow rate.Experimental results indicated that seawater performed better than distilled water, by exploiting its inherent alkalinity. The desulfurization performance was improved by increasing the liquid flow rate and the gas residence time and by decreasing the SO2 concentration. SO2 capture efficiencies up to 93% were measured under the present operating conditions. The experimental data were further compared with calculations performed with an available model for SO2 absorption in fall‐down droplets within a simple plug‐flow reactor. Model calculations were carried out by using all parameters' values as measured in the present experimental campaign. Model results well fit the experimental data, even if a slight underestimation of the desulfurization efficiency is reported. The likely reasons are the assumed plug flow of gas as well as the neglected contribution to SO2 capture by water film falling at the wall. © 2012 American Institute of Chemical Engineers Environ Prog, 32: 1179–1186, 2013

Hydromorphological features are crucial in structuring habitats for freshwater organisms. The quantification of these variables is often performed through accurate measuring or detailed estimation, but their assessment is not always feasible for river management purposes. Economic and time constraints often lead to difficulty in creating simple summaries of collected data for practical use. The Lentic-lotic River Descriptor (LRD) was developed to identify the character of a river site in terms of local hydraulic conditions. Information about the presence of flow types, channel substrates, in-stream vegetation, organic debris and artificial features is included in its calculation. The main aim of this paper is to investigate whether the lentic-lotic character of a river site, as summarized with the LRD descriptor, is relevant to aquatic invertebrate communities in nearly natural river sites. Invertebrate data were collected with multi-habitat, proportional sampling and hydromorphological information was gained by applying the CARAVAGGIO method (river habitat survey technique) in the field. The dataset was generated from High or Good ecological status river sites located in Mediterranean areas of Italy. Correspondence Analysis was performed to relate the invertebrate community structure to a set of catchment-scale, reach-scale and chemical environmental variables. The results of the multivariate analysis indicate that LRD provides a persuasive explanation of the most important axis of variation in benthic data. This paper also presents the optimal LRD range for a set of invertebrate taxa, accompanied by a short discussion of their potential use in conservation issues.

The present work focuses on the effects of pressure on the quality of char and primary tar produced from fast pyrolysis of lignocellulosic biomass. Heat treatment has been carried out in a heated strip reactor (HSR) at 1573 K in nitrogen at 2, 4, 8 bar, with holding times of 3 s and heating rate of 104 K/s. The equipment allows quenching the volatiles as soon as they are emitted from the particles and collecting them for further chemical analyses. The char samples are also collected for thermogravimetric analysis in air. The DTG curves in air of char prepared at 2 bar shows two resolved peaks. Increasing the pressure of heat treatment from 2 to 4 bar has a minor effect on char reactivity, whereas further increase to 8 bar drastically changes the char combustion patterns, and the DTG curves exhibit only one well defined peak. For all the process conditions investigated, Oxo-aromatics are the dominant species in the tar. Benzendiol prevails in the 2 bar tar, followed by oxo-aromatic compounds related to lignin structure, while PAHs are mainly present as Fluorene. When pressure increases, Phenols compounds drastically prevail, and PAHs as Anthracene and Pyrene appear.

In this work, a novel enhanced deep borehole heat exchanger (EDBHE) was proposed to improve heat extraction efficiency based on the jet grouting method. By means of this technology, a soilcrete zone with high thermal conductivity was built near the wellbore. To analyze the feasibility and efficiency of this method, we firstly constructed a validated deep borehole heat exchanger (DBHE) model based on the field experimental data. Numerical simulations were carried out to investigate the 30-year production performance of EDBHE. Results demonstrated that the jet grouting method is an efficient way for improving thermal output of DBHE. It is evaluated that the average annual heat production rate over a 30-year heating period of EDBHE is 463.2 kW, which is 1.27 times as that of DBHE. Sensitivity analyses indicate that the heat production rate and outlet temperature mainly depend on the height and radius of the artificial soilcrete zone. However, thermal output is not sensitive to thermal conductivity of the soilcrete zone due to the higher thermal resistance of the geological formation. For the experimental site used in this work, the recommended height, radius, and thermal conductivity of the soilcrete are 1000 m, 1.0 m, and 50 W/m °C, respectively.

The setup of an economic and sustainable method to increase the production and commercialization of products from microalgae, beyond niche markets, is a challenge. Here, a cascade approach has been designed to optimize the recovery of high valuable bioproducts starting from the wet biomass of Galdieria phlegrea. This unicellular thermo-acidophilic red alga can accumulate high-value compounds and can live under conditions considered hostile to most other species. Extractions were performed in two sequential steps: a conventional high-pressure procedure to recover phycocyanins and a solvent extraction to obtain fatty acids. Phycocyanins were purified to the highest purification grade reported so far and were active as antioxidants on a cell-based model. Fatty acids isolated from the residual biomass contained high amount of PUFAs, more than those recovered from the raw biomass. Thus, a simple, economic, and high effective procedure was set up to isolate phycocyanin at high purity levels and PUFAs.