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The continued discharge of pharmaceuticals and personal care products (PPCPs) into the environment due to their widespread use and the lack of effective systems for their removal from water is a global problem. In this study, the dissipation of ibuprofen, diclofenac and triclosan added simultaneously in biopurification systems (BPSs) with different compositions and their effect on the microbial community structure was analysed. Three BPSs, constituted by mixtures of soil (S), peat (P), or raw wet olive mill cake (A) or its vermicompost (V) and straw (S) were prepared (SPS, SAS and SVS). Sorption and degradation experiments were carried out. After 84 days of incubation, more than 85% of each PPCP applied had dissipated. Methyl-triclosan was determined to be highest in the SVS biomixture. Biomixtures with lower C/N ratio and higher alpha diversity were the most effective in the removal of PPCPs. Initially, the BPS biomixtures showed a different microbial structure dominated by Proteobacteria, Actinobacteria and Bacteroidetes but after addition of PPCPs, a similar pattern was observed in the relative abundance of the phylum Chloroflexi, the class Sphingobacteriia and the genus Brevundimonas. These biopurification systems can be useful to prevent point source contamination due to the disposal of PPCP-contaminated waters., This work was funded by project CTM2017-86504-R of the Agencia Estatal de Investigación (AEI) of Spain and the European Regional Development Fund (FEDER).

Biobed bioremediation systems (BBSs) are widely used to prevent point-source pesticide contamination of water. However, these systems have never been investigated for possible elimination of emerging contaminants (ECs). In this study, two biobed systems, involving biomixtures elaborated with soil and raw olive mill cake (SCP) or its vermicompost (SVP), were assayed to determine their effectiveness in removing the ECs diclofenac, ibuprofen and triclosan from effluent wastewater. Adsorption, incubation and bioaccesibility experiments were carried out. The SCP and SVP biomixtures showed greater adsorption capacity than the soil (S), used as reference. In SVP and S, the degradation rates of the ECs applied were similar and over 94% of these compounds was removed after 84 days of incubation. However, SCP biomixture had a lower removal rate and the percentage of ECs removed ranged from 32 to 68%. In SVP, the bioaccesible fraction (E) reveals that approximately 82% of triclosan and diclofenac adsorption occurred in bioaccesible sites, thus explaining the more efficient decontamination observed in this biomixture. The relationship established between the bioaccesible and biodegradable fractions suggests that E values are a useful tool for predicting the endpoints of ECs biodegradation in bioremediation systems. UPLC/Q-TOF-MS analysis of samples showed different metabolite products., This study was supported by the Spanish Ministry of Science and Innovation and co-funded by the European FEDER program (project CTM2013-44271-R). The authors would like to thank Lourdes Sánchez Moreno from the Estación Experimental del Zaidín (EEZ-CSIC, Granada, Spain), as well as Andreu Fabregat and Pablo de la Iglesia from the Barcelona Water Company's Contaminants Laboratory for technical support. We also wish to thank Michael O'Shea for proofreading the text.

This study describes a new bioaugmentation alternative based on the application of aqueous aerated extracts from a biomixture acclimated with ibuprofen, diclofenac and triclosan. This bioaugmentation strategy was assayed in biopurification systems (BPS) and in contaminated aqueous solutions to accelerate the removal of these emerging contaminants. Sterilized extracts or extracts from the initial uncontaminated biomixture were used as controls. In BPS, the dissipation of 90% of diclofenac and triclosan required, respectively, 60 and 108 days less than in the controls. The metabolite methyl-triclosan was determined at levels 12 times lower than in controls. In the bioaugmented solutions, ibuprofen was almost completely eliminated (99%) in 21 days and its hydroxylated metabolites were also determined to be at lower levels than in the controls. The plasmidome of acclimated biomixtures and its extract appeared to maintain certain types of plasmids but degradation related genes became less evident. Several dominant OTUs found in the extract identified as Flavobacterium and Fluviicola of the phylum Bacteroidetes, Thermomicrobia (phylum Chloroflexi) and Nonomuraea (phylum Actinobacteria), may be responsible for the enhanced dissipation of these contaminants. This bioaugmentation strategy represents an advantageous tool to facilitate in situ bioaugmentation., This study was supported by the Spanish Ministry of Economy and Competitiveness and the Spanish State Research Agency (AEI) (projects CTM2013-44271-R and CTM2017-86504-R), and co-financing from the European Regional Development Fund (ERDF). Inés Aguilar-Romero thanks her FPI grant. GC-MS analyses were carried out by the Scientific Instrumentation Services of the Estación Experimental del Zaidín (CSIC), Granada, Spain.

Enormous quantities of winery wastes are generated in grape-growing regions around the world. The aim of this studynwas to gather key pilot-scale data on the use of different winery wastes in a vermitechnological system to produce commercially viable soil organic amendments. Exhausted grape marc (G), lees cake mixed with exhausted grape marc (LG), and biosolid vinasse mixed with vine shoots (SV) were tested as substrates for vermicomposting. Changes in earthworm development, enzyme activities, chemical properties, organic matter fractions, and phytotoxicity were assessed along 6 months of vermicomposting and after a subsequent maturation period of 2 months. The organic matter composition of the three produced vermicomposts was also characterized using pyrolysis-gas chromatography (Py-GC). During vermicomposting, earthworm number increased significantly in both LG and SV, with earthworm biomass peaking after 2 months. By contrast, G failed to provide adequate nourishment for earthworms. Dehydrogenase and hydrolytic enzyme activities peaked after 2 months and then declined as available organic compounds diminished. Overall, hydrolytic enzyme activities tended to stabilize during maturation. After vermicomposting and maturation, total organic carbon, soluble carbon, phytotoxicity, electrical conductivity, C/N ratios, and polyphenol content decreased, whereas pH, phosphorus, micronutrients, and humification ratios increased. Using Py-GC, the vermicompost from SV was found to contain the most evolved organic matter in view of its higher degree of humification and lower mineralization index. Nevertheless, all the different winery wastes could be biotransformed, by using vermitechnology, into high value-added soil organic amendments with a degree of stability and maturity adequate to be marketed., This study was co-funded by the Junta de Andalucía (Project AGR-138) and the European FEDER program.

Biobeds systems containing soil, peat and straw (SPS) are used worldwide to eliminate pesticide point-source contamination, but implantation is difficult when peat and/or straw are not available. Novel biobeds composed of soil, olive pruning and wet olive mill cake (SCPr) or its vermicompost (SVPr) were assayed at pilot scale for its use in olive grove areas. Their removal efficiency for five pesticides applied at high concentration was compared with the biobed with SPS. The effect of a grass layer on the efficiency of these biobeds was also evaluated. Pesticides were retained mainly in the upper layer. In non-planted biobeds with SCPr and SVPr, pesticides dissipation was higher than in SPS, except for diuron. In the biobed with SVPr, with the highest pesticide dissipation capacity, the removed amount of dimethoate, imidacloprid, tebuconazole, diuron and oxyfluorfen was 100, 80, 73, 75 and 50%, respectively. The grass layer enhanced dehydrogenase and diphenol-oxidase activities, modified the pesticides dissipation kinetics and favored the pesticide downward movement. One metabolite of imidacloprid, 3 of oxyfluorfen and 4 of diuron were identified by GC-MS. These novel biobeds represent an alternative to the traditional one and a contribution to promote a circular economy for the olive-oil production., This work was supported by the Spanish Science and Innovation Ministry and co-funded by European funds through the projects CTM2010-16807 and CTM2013-44271-R . Authors thank Fernando Calvo Rivas and Rafael Núñez for their technical support.

In this work, we aimed to test the capacity of an exogenous source of tryptophan to stimulate the bacterial biosynthesis of the phytohormone indole-3-acetic acid (IAA) in agro-industrial by-products, trying to gain insight into the role of key genes involved in the indole-3-pyruvic acid pathway (IPA) for bacterial IAA synthesis. Sunflower-oil cake was mixed with a 9-months-old vermicompost olive wastes and then vermicomposted for 60 days using earthworms Eisenia foetida. Synthetic tryptophan and no tryptophan source were used as controls. For this, a novel set of primers targeting bacterial aldehyde-dehydrogenase (ALDH)-encoding genes involved in the last step of the IPA route was designed and tested, and a method involving ultrasound-assisted extraction of IAA and subsequent analysis by liquid chromatography–tandem mass spectrometry was optimized. Re-starting the vermicomposting process increased bacterial abundance and the number and the expression of ALDH genes but not the IAA content in the final vermicomposts, meaning that the transcription of the ALDH genes could be not quite high enough to change the overall level of the existent IAA. After that, the effects of the resulting vermicompost were evaluated on the bacterial microbiome of the pepper (Capsicum annuum L.) rhizosphere. When used as amendments, ALDH gene expression was detected in the pepper’s rhizosphere after 3 months of growth only when vermicompost incorporating sunflower cake was used, where the highest levels of IAA were also detected. The results indicate the presence of the ALDH genes in the chromosome of most of vermicompost-borne bacteria, probably not specific for IAA synthesis, and that the IPA pathway may not be the main biosynthesis pathway for IAA in vermicompost-borne bacteria.

Installation of biobed biopurification systems at farm level, traditionally composed of soil, peat and straw, to reduce point source contamination is difficult in some countries where peat is not environmentally or economically feasible. This study evaluates the use of local organic wastes from olive oil production such as wet olive cake and its vermicompost as substitutes of peat and olive tree pruning as substitute of straw to perform robust biobeds capable of removing mixtures of pesticides at high concentrations. Adsorption capacity of the novel biomixtures was comparable to or higher than traditional one. The biomixture with soil and olive tree pruning showed the highest pesticides adsorption, except for imidacloprid. The biomixture with soil, vermicompost and olive tree pruning showed dissipation efficiency of dimethoate, imidacloprid and oxyfluorfen (>73%) higher than traditional biobed. Meanwhile, the biomixture with soil and vermicompost was the alternative biomixture with the highest dissipation of diuron (54%) and tebuconazole (35%) but it was lower than traditional biomixture (59 and 47% for diuron and tebuconazole, respectively). The low dissipation of these compounds (

The biomixture composition and the presence of a grass layer in a biobed bioremediation system can improve the performance of these systems to minimize pesticide point-source contamination. In this study, a novel biomixture composed with organic wastes from vineyards and wine industries (vermicompost of winery wastes and vine shoots) and top soil (W) was elaborated. The impact of three pesticides, commonly used in vineyards, on its microbial activity and on the development of turfgrass was determined in a short-term experiment. Moreover, the dissipation of the assayed pesticides was evaluated to stablish their distribution patterns between the turfgrass and the biomixture. For comparison, the original biomixture composed with top soil, peat, and straw (P) was also studied. After 15 days of pesticide application, the development of the turfgrass in both biomixtures was similar. However, the oxidoreductases (dehydrogenase and ortho-diphenol oxidase) and the hydrolytic (FDA and β-glucosidase) enzyme activities were greater in W-biomixture than in P-biomixture. The dissipation of metalaxyl and imidacloprid recorded in the W-biomixtures was significantly greater than in the P-biomixtures. The pesticide dissipation in W-biomixtures followed the same order of their octanol water partition coefficients. Except for tebuconazole, the lower biological activity in the P-biomixture would explain the limited pesticide dissipation. In the grassed biomixtures, most (> 83%) of the non-dissipated imidacloprid and tebuconazole remained in the biomixtures, while metalaxyl was rapidly translocated to the aerial part of the turfgrass. Our results show the potential capability of the novel biomixture as an alternative to the original one in a biobed., This work was supported by the Spanish Ministry of Economy and Competitiveness co-funded by European funds through the Project CTM2013-44271-R . Authors thank Celia Cifuentes for their technical assistance.

An incubation experiment was conducted to evaluate the effects that three types of biomass ash, each applied at two doses, exert on the nutrient availability in a calcareous soil. The application of the ash from dry olive cake or greenhouse vegetable wastes significantly increased soil ammonium bicarbonate-diethylenetriaminepentaacetic acid (AB-DTPA)-extractable phosphorus (P), potassium (K), sodium (Na), copper (Cu) and zinc (Zn) as well as exchangeable and non-exchangeable K and Na. Wood ash was effective only for increasing soil ABDTPA-extractable Zn and Cu. By contrast, the three types of biomass ash hardly increased soil ABDTPA-extractable Fe or Mn. The high content in carbonate of the soil appears to minimize the potential of the ash to increase the micronutrients availability, which shortened with longer incubation time. Soil ABDTPA-extractable heavy metals were not detected in the different treatments tested. Other parameters of the soil, as pH and organic carbon, were scarcely affected by...

In biobed bioremediation systems (BBSs) with vermicomposts exposed to a high load of pesticides, 6 bacteria and 4 fungus strains were isolated, identified, and investigated to enhance the removal of pesticides. Three different mixtures of BBSs composed of vermicomposts made from greenhouse (GM), olive-mill (OM) and winery (WM) wastes were contaminated, inoculated, and incubated for one month (GMI, OMI and WMI). The inoculums maintenance was evaluated by DGGE and Q-PCR. Pesticides were monitored by HPLC-DAD. The highest bacterial and fungal abundance was observed in WMI and OMI respectively. In WMI, the consortia improved the removal of tebuconazole, metalaxyl, and oxyfluorfen by 1.6-, 3.8-, and 7.7-fold, respectively. The dissipation of oxyfluorfen was also accelerated in OMI, with less than 30% remaining after 30d. One metabolite for metalaxyl and 4 for oxyfluorfen were identified by GC-MS. The isolates could be suitable to improve the efficiency of bioremediation systems.

8 págs., 3 figuras y 4 tablas, A better understanding of how varying the proportion of different organic wastes affects humic acid (HA)formation during vermicomposting would be useful in producing vermicomposts enriched in HAs. With the aim of improving the knowledge about this issue, a variety of analytical techniques [UV–visible spectroscopic, Fourier transform infrared, fluorescence spectra, solid-state cross-polarization magic-angle spinning (CPMAS) 13C nuclear magnetic resonance (NMR) spectra, and thermal analysis] was used in the present study to characterize HAs isolated from two mixtures at two different ratios (2:1 and 1:1)of tomato-plant debris (TD) and paper-mill sludge (PS) before and after vermicomposting. The results suggest that vermicomposting increased the HA content in the TD/PS 2:1 and 1:1 mixtures (15.9% and 16.2%, respectively), but the vermicompost produced from the mixture with a higher amount of TD had a greater proportion (24%) of HAs. Both vermicomposting processes caused equal modifications in the humic precursors contained in the different mixtures of TD and PS, and consequently, the HAs in the vermicomposts produced from different waste mixtures exhibited analogous characteristics. Only the set of analytical techniques used in this research was able to detect differences between the HAs isolated from each type of vermicompost. In conclusion, varying the proportion of different wastes may have a stronger influence on the amount of HAs in vermicomposts than on the properties of HAs., This study was financed by ‘‘Junta de Andalucía’’ Project P05-AGR-00408. M.J. Fernández-Gómez thanks the Science and Innovation Ministry for their FPU doctoral Grant (AP2006-03452). J.M. Fernández is the recipient of a fellowship from the JAE-Doc subprogram financed by the CSIC and the European Social Fund. The authors also thank the professional proof corrector D. Nesbitt for assisting in the writing of the manuscript.

Reuse and recycling of biomass ashes as new resources can boost the development of a circular and sustainable economy. This requires knowledge concerning the characteristics and properties of the ash for different applications. In this study, novel biomass ashes from combustion, at different temperatures, of olive-oil wastes and from the gasification of greenhouse vegetables wastes were characterized and compared by ICP-MS, XRF, XRD, FT-IR, and SEM-EDS among other analytical techniques. All ashes were alkaline (pH between 9.9 and 13.3) and had high salinity (42–132 dS m). They had high amounts of Si, Ca, and K; moderate of P, Mg, Al, S, and Cl; and low Na and heavy metals. By comparison, the ash from greenhouse vegetables waste was richer in aluminosilicates and calcite whereas those from olive-oil wastes showed the presence of soluble minerals such as carbonates, sulphates, and chlorides. The high K amounts (23–58 g kg) found in the ashes from olive wastes would enable its reuse as natural K fertilizer or as a raw material in the manufacture of K chemical fertilizers. The ashes resulting from higher temperatures had lower carbon contents, higher amounts of particles, This study was financed by the Junta de Andalucía, Spain, through Excellence Project P07-RNM-2746. M. Quirantes thanks the Junta de Andalucía, for their doctoral grants associated to project P07-RNM-2746. We thank the biomass power plants of Gasification Plant of Albaida, Nijar, Almeria; Energy La Loma S.A., Villanueva del Arzobispo, Jaén; Baena Agroenergy S.L., Córdoba; Oleícola El Tejar S.L., Palenciana, Córdoba and the olive-oil extraction plant of Romeroliva, S.L., Deifontes, Granada for providing the ashes from greenhouse vegetable wastes, dry olive cake, wet olive cake mixed with olive leaves or bagasse and olive pits, respectively, used in this study. The authors appreciate the assistance of J. Huertas, G. Delgado and R. Delgado for, respectively, XRD, FRX and SEM-EDS analysis. The authors also thank David Nesbitt for assisting in the translation of the manuscript into English.

Below-ground soil microorganisms can modulate above-ground plant-insect interactions. It still needs to be determined whether this is a direct effect of single species or an indirect effect of shifts in soil microbial community assemblages. Evaluation of the soil microbiome as a whole is critical for understanding multi-trophic interactions, including those mediated by volatiles involving plants, herbivorous insects, predators/parasitoids and microorganisms. We implemented a regulated system comprising Nerium oleander plants grown in soil initially containing a sterile/non sterile inoculum, herbivore Aphis nerii and predator Chrysoperla carnea. After aphid attack, plants emitted a characteristic blend of volatiles derived from two biosynthetic classes: fatty acid catabolites and aromatic-derived products. Three aliphatic compounds were mainly detected in plants grown in the inoculated microbial soil, a blend which was preferentially chosen by C. carnea adult females. The contrasting effect of the initial inocula was attributed to the different microbial consortia developed in each treatment. We argue that differences in the relative abundance of the active microbial communities in the rhizosphere correlate with those in the emission of selected volatile compounds by attacked plants. The mechanisms involved in how the functional soil microbiome modulates inducible indirect defence of plants are discussed., This work was supported by ERDF-cofinanced grant RECUPERA 2020 from the Spanish Ministry of Economy and Competitiveness-CSIC and Project AGR 1419 from Junta de Andalucía, Spain. E. Rodríguez held a postdoctoral contract (DOC-INIA program) granted by Spanish National Institute for Agricultural and Food Research and Technology (INIA) and the European Social Fund. The volatiles and chemical analyses were made at the Scientific Instrumentation Service, EEZ-CSIC, Granada, Spain. We would also like to thank Dr. Fernando Reyes from Fundación Medina for his help in discussing the results of the analysis of volatiles and Michael O´Shea for assisting in the translation of the original manuscript into English

International audience; The fate and impact of pesticide on soil depend partly on the agricultural practices, such as prior treatment with pesticide and/or organic amendments. As a means of determining how the previous soil conditions can affect the fate of imidacloprid (IMI) and its effect on soil functions, experiments were made with soil samples, double-amended or not with either vine-shoot (W) or olive cake (O) vermicompost or contaminated or not with IMI. These soil samples, incubated for 3 months, were placed in two microcosms (M1 with the pre-amended soils and M2 with the pre-exposed soils), treated with IMI and amended with vermicomposts and then incubated for 3 months. The IMI distribution on soil fractions, sorption processes, dissipation kinetics, and biochemical as well as genetic structure and bacterial abundance were determined to assess the fate and impact of IMI on the soil. The addition of W vermicompost to the soil reduced the IMI availability. The dissipation kinetic in soils from M1 and M2 followed, respectively, a single first-order and a double first-order in parallel models. The lowest IMI persistence corresponded to the soil from M2 amended with O-vermicompost with DT50 and DT90 values of 67 d and 265 d, while in the other soils 90% dissipation required >512 d. The vermicomposts-amended contaminated soils increased the dehydrogenase activity by 2- and 4-fold respect the control soils. However, the urease activity decreased due to the IMI influence. The changes in the bacterial community in the contaminated soil amended with O-vermicompost during incubation were correlated with the dissipation rate constant of IMI, suggesting a better tolerance of microorganisms to IMI. Thus, in the soil contaminated with IMI, the amendment with the vermicompost from olive cake can mitigate the impact of this insecticide on soil functions and promote its depuration capability while minimizing environmental risks.

A hazardous contaminant, 3,4-dichloroaniline (DCA) is widespread in the environment due to its extensive use in the manufacture of chemicals and its application in different sectors. The ability of fungi grow on in winery wastes in the preconditioning period of vermicomposting to degrade DCA was investigated. Three filamentous fungi (F1, F2, and F3) were isolated and one identified as Aspergillus niger and two as Fusarium sp. strains. The culture media with the fungus alone or in consortium (Fmix) with DCA as the nitrogen source were analyzed by solid-phase microextraction and gas chromatography-mass spectrometry (SPME-GC/MS). The fastest degradation rate was measured in Fmix with a DT50 of 0.85day(-1). Fusarium sp. and A. niger differed in the metabolism of DCA. Five metabolites were identified as a result of oxidation, co-denitrification, N-acetylation, and polymerization reactions. The major metabolites were 3,4-dichloroacetanilide and dichloroquinolines. The azo-metabolites tetrachloroazobenzene and tetracloroazoxybenzene and 3,4-dichloronitrobenzene were found in minor amounts but appeared to be the most persistent in the Fusarium cultures (half-lives ranging from 8.3 to 30.9 days). This study highlights the metabolic potential of microorganisms in the preconditioning period of the vermicomposting process and its possible application for in situ bioremediation strategies.

The enormous quantity of plant waste produced from greenhouse tomato crops is an environmental problem that should be solved by recycling that waste into valuable organic products through low-cost technologies, such as vermicomposting. Feasibility of vermicomposting greenhouse tomato-plant waste (P) using paper-mill sludge (S) as complementary waste was investigated by this study. Earthworm development in P, S, and two mixtures of both wastes was monitored over 24 weeks and compared with that in cow dung (D), an optimum organic-waste to be vermicomposted. The effectiveness of vermicomposting to biostabilize those wastes was assessed by analysing phospholipid fatty acid composition, chemical features, plant-nutrient content, metal concentration, enzyme activities, and germination index (GI). A commercial vermicompost was also analyzed and taken as a reference of vermicompost quality. Earthworms did not survive in P alone, but a mixture of P with S at a ratio of 2:1 or 1:1 resulted in earthworm development similar to that observed in D. Phospholipid fatty acid analysis revealed that earthworm activity strongly transformed initial microbiota inhabiting the wastes, giving rise to vermicompost microbial communities which were similar to that of a commercial vermicompost. Both mixtures of P and S were properly biostabilized through vermicomposting, as indicated by decreases in their C:N ratio and enzyme activities together with increases in their degree of maturity (GI ~ 100 %) after the process. This study demonstrates that the vermicomposting of tomato-plant waste together with paper-mill sludge allows the recycling of both wastes, thereby improving the environmental sustainability of greenhouse crops.

Hazardous contaminants in water and biomass fly ash spillage are causes for environmental and health concern. We selected five fly ashes generated from olive-mill (O,P, G and H) and greenhouse vegetable (I) waste used as biomass fuel in order to quantify their capacity to remove diuron and 3,4-dichloroaniline (DCA) from water. To understand the sorption processes involved, four kinetic models and two adsorption isotherms were assayed. The pseudo second-order kinetic showed the best fit (R2>0.99). The initial adsorption rate constant was found to be faster for DCA than for diuron. The Freundlich adsorption constants of ashes O, P, G and H for diuron were more than 2-fold higher than for DCA (Kf=109-16μg1-1/ng-1mL-1). The alkaline pH of these fly ashes plays an important role in the adsorption process. Sorption/desorption processes were significantly affected by iron oxide content. DCA sorption was also influenced by particle size and carbon content. Low hysteresis coefficient values (H=0.01-0.26) revealed an irreversible sorption process. The study presents novel information on the immobilization of hazardous chemicals in water by biomass fly ashes generated from olive-oil industry and greenhouse crop waste.

This study, through an incubation experiment, evaluates the effect that different biomass ashes exert on the extractability of nutrients and some chemical parameters and dehydrogenase activity of a slightly acid soil. Three types of as were selected: two new ashes generated by the dry combustion of olive cake or by gasification of greenhouse vegetable wastes, and a third produced by wood combustion. The ash significantly increased the pH, electrical conductivity, and dehydrogenase activity of the soil. Dry olive-cake ash was the most effective in raising the levels of soil AB-DTPA extractable P, K, and Cu. By contrast, wood ash caused the greatest increases in soil AB-DTPA-extractable Zn. The three as he showed little effectiveness for increasing soil ABDTPA extractable Fe and Mn. Ash from dry olive cake could be used as a low-cost potassium fertilizer.

A greenhouse pot experiment was conducted to investigate how the addition of two vermicomposts (commercial or produced from damaged greenhouse tomatoes) and/or inoculation with arbuscular mycorrhizal (AM) fungi affected availability and extractability of P, K and trace metals and biochemical quality of a soil contaminated with heavy metals. The pots were planted with Trifolium repens L., which was harvested 40 days after germination. Shoot and root dry matter of T. repens increased by the addition of both vermicomposts. P, K, Fe, Mn, Cu and Zn uptake by T. repens increased after vermicompost addition, whereas Ni, Pb and Cd concentrations were below the detection limit of the method used. After harvest, AB-DTPA-extractable Fe, Cu, Zn, Cd and Pb decreased in the organically amended soil, whereas AB-DTPA P, K and Mn increased. The addition of both vermicomposts, particularly which made from damaged tomatoes, boosted dehydrogenase, β-glucosidase and urease activities in the postharvest soil, implying a higher microbial functional diversity and biochemical quality in this amended soil. Although phosphatase activities were greater in the postharvest soils with higher AB-DTPA-extractable metals, the other enzyme activities were negatively affected. The inoculation of the soils with AM fungi had weak effects on plant growth, as well as on the availability and extractability of metals and enzyme activities compared to non-inoculation.

This study describes the use of denaturing gradient gel electrophoresis (DGGE) and COMPOCHIP (i.e. a microarray targeting typical bacteria of stabilized organic materials and pathogenic bacteria) for investigating the bacterial communities of four different vermicomposts. These included a commercial vermicompost produced from cattle manure (CM) and three vermicomposts produced at pilot-scale by recycling: damaged tomato fruits (DT); olive-mill waste mixed with biosolids (OB); and winery wastes (WW). DGGE provided distinctive fingerprints of each vermicompost, which were statistically related to their particular chemical features. The comparison of the various vermicompost fingerprints showed that they contained bacterial communities with an average similarity coefficient of close to 80%. COMPOCHIP detected the presence of Sphingobacterium, Streptomyces, Alpha-Proteobacteria, Delta-Proteobacteria, and Firmicutes in all the vermicomposts. COMPOCHIP showed differences in the abundance of particular bacterial taxa among the vermicomposts, giving an idea about the usefulness of each vermicompost in the search for bacteria valuable to biotechnology. The joint use of DGGE and COMPOCHIP is a useful tool to compare vermicompost bacterial communities and to assess the potential of different vermicomposts as bioactive organic materials.

The relationships between vermicompost chemical features, enzyme activities, community-level physiological profiles (CLPPs), fungal community structures, and its microbial respiratory response to pesticides were investigated. Fungal community structure of vermicomposts produced from damaged tomato fruits (DT), winery wastes (WW), olive-mill waste and biosolids (OB), and cattle manure (CM) were determined by denaturing gradient gel electrophoresis of 18S rDNA. MicroResp™ was used for assessing vermicompost CLPPs and testing the microbial response to metalaxyl, imidacloprid, and diuron. Vermicompost enzyme activities and CLPPs indicated that WW, OB, and DT had higher microbial functional diversity than CM. The microbiota of the former tolerated all three pesticides whereas microbial respiration in CM was negatively affected by metalaxyl and imidacloprid. The response of vermicompost microbiota to the fungicide metalaxyl was correlated to its fungal community structure. The results suggest that vermicomposts with higher microbial functional diversity can be useful for the management of pesticide pollution in agriculture.

Huge quantities of discarded fruits generated from greenhouse crops represent a worldwide environmental problem. The aim of this work was to assess the efficiency of vermicomposting as a recycling management option for biotransforming tomato-fruit wastes from greenhouses into an organic nutrient-rich product available for agricultural purposes. A pilot vermireactor was constructed. It was provided with a manure layer, where an initial population of Eisenia fetida was introduced and fed continuously at a high organic loading rate (13.6 kg TOC m−3 wk−1) for 150 days. Vermicompost chemical and enzymatic parameters as well as the bacterial and fungal community structure were determined for 210 days (vermicomposting plus a maturation period). Earthworm biomass increased after 90 days, and then declined due to increasing pH, electrical conductivity and ammonium concentration. The temporal patterns of dehydrogenase, β-glucosidase, protease and urease were related to earthworm growth and the stabilization of organic matter. Bacterial DGGE profiles differed between the period of degradation of labile substrates and the maturation step. Fungal communities at the stage of maximum earthworm biomass differed most, suggesting a gut passage effect. The end product was chemically stable and enriched in nutrients, demonstrating that tomato-fruit wastes can be successfully vermicomposted into a valuable soil amendment. We suggest continuous-feeding vermicomposting as an environmentally sound management option for greenhouse wastes.

Mineral fertilizers, organic amendments, and pesticides are inputs commonly used in conventional farming practices. The aim of this study was to evaluate the effects of single or combined applications of spent grape marc-vermicompost, urea, and/or diuron on soil-enzyme activities and the persistence of this herbicide in soils with low organic carbon content. The application of vermicompost enhanced dehydrogenase (DHase) enzyme activity over time but altered soil urease activity to a very limited extent. The reduction in diuron concentrations and the increase in DHase activity indicated that the soil microorganisms were capable of degrading the ureic herbicide. Treatment with vermicompost and diuron had a stimulatory effect on soil microbial activity. On the whole, the application of diuron and urea to the vermicompost-amended soil raised DHase and urease activity to maximum levels (>3 μg INTF g −1 h −1 and >47 μg NH 4 + g −1 h −1 , respectively). The application of urea to the unamended and vermicompost-amended soil decreased diuron persistence from 18.8 and 33 d to 12.5 and 15 d, respectively. Our findings show that although vermicompost additions reduce diuron availability, this boosts diuron degradation when combined with urea. These additions, under different soil management conditions, minimize the bioavailability and persistence of diuron and consequently the risk of leaching and seepage into aquifers. Compared with untreated soils, these types of treated soils could also improve agricultural sustainability and the quality of the environment.

Summary Vermicomposts from the wine and distillery industry containing spent grape marc (V1), biosolid vinasse (V2) and alperujo (V3) from the olive-oil industry were investigated as organic amendments to a sandy and a clay soil with low organic carbon (OC) contents (≤1%). The sorption-desorption process was studied in batch experiments using diuron as a non-ionic herbicide model. The effect of soil and vermicompost characteristics, the solution's ionic strength and incubation time of amended soils on the sorption process was studied. The addition of vermicompost changed soil properties and enhanced sorption capacity by two- to four-fold. The Koc variability showed that exogenous OC composition influenced diuron sorption. Vermicompost V1, which had the largest OC and lignin content, recorded the largest sorption increment. Vermicompost V3, which had the greatest dissolved organic carbon content and a high degree of humification, made the smallest contribution to sorption. Sorption was also dependent on extraneous calcium in the solution. The incubation of amended soils reduced diuron sorption efficiency except with V3. Pyrolysis-gas chromatography (Py-GC) analysis was a useful tool to characterize the vermicomposts and to understand the variation of diuron sorption constants after vermicompost incubation. This research encourages the use of vermicompost from agro-industrial wastes as a sustainable means to minimize the side effects of neutral herbicides.

Kinetic studies are of great concern for understanding the processes and parameters involved in the sorption of pollutants by soils. Sorption kinetics of imidacloprid and diuron in eight soils of different characteristics, with very low organic carbon content were investigated. Pseudosecond-order kinetic reactions closely correlate with the experimental kinetic (R(2)0.98) in all soils. The sorbed amount of diuron was higher than that for imidacloprid. The low OC content of these soils correlated neither with the sorbed amount nor with the kinetic parameters for both pesticides. Imidacloprid sorption was correlated with silt and sand content and cation exchange capacity (CEC); meanwhile for diuron, no correlation was found. Thus, sorption kinetics take place throughout different mechanisms related mainly to the chemical character of the pesticides. Sorption kinetic parameters determined using three of the four models selected (pseudosecond-order kinetic reactions, Elovich equation, and Weber-Morris models) have been shown to be worthy to distinguish the process controlling the sorption kinetic of both pesticides.

Three different substrates from winery and distillery wastes including a spent grape marc (SGM), a mixture of SGM and lees cake (SGML) and a mixture of biosolid vinasse and vine shoots (BvS) were vermicomposted with Eisenia andrei for 8 months. The chemical changes occurring in the bulk substrates and in their humic acid-like (HAL) fractions were investigated. Vermicomposting produced a decrease of total organic C content and C/N ratio, and an increase of total extractable C and humic acid C contents in the three substrates. The HAL fractions in the initial substrates were characterized by a marked aliphatic character, small acidic functional group content, a marked presence of proteinaceous materials and polysaccharide-like structures, extended molecular heterogeneity and small degrees of aromatic ring polycondensation, polymerisation and humification. After vermicomposting, the chemical and structural characteristics of HAL fractions approached those typical of soil humic acid. In particular, a loss of aliphatic, polypeptidic and carbohydrate components, and an increase in oxygenated and acidic functional groups occurred. Results obtained showed that vermicomposting is a suitable treatment for transforming fresh organic matter in SGM, SGML and, especially, BvS into humified forms, thus enhancing the quality of these materials as soil organic amendments. Further, the mixture SGML yielded slightly better results in terms of HAL fraction quality and humification degree of the final product, with respect to SGM. © 2007 Elsevier B.V. All rights reserved.

Batch sorption experiments of the insecticide imidacloprid by ten widely different Spanish soils were carried out. The sorption was studied for the active ingredient and its registered formulation Confidor. The temperature effect was studied at 15 degrees C and 25 degrees C. The addition of a vermicompost from spent grape marc (natural and ground), containing 344 g kg(-1) organic carbon, on the sorption of imidacloprid by two selected soils, a sandy loam and a silty clay loam, having organic carbon content of 3.6 g kg(-1) and 9.3 g kg(-1), respectively, was evaluated. Prior to the addition of this vermicompost, desorption isotherms with both selected soils, were also performed. The apparent hysteresis index (AHI) parameter was used to quantify sorption-desorption hysteresis. Sorption coefficients, K(d) and K(f), for the active ingredient and Confidor(R) in the different soils were similar. Sorption decreased with increasing temperature, this fact has special interest in greenhouse systems. A significant correlation (R(2)=0.965; P

An incubation experiment was conducted to ascertain the effects of three olive‐derived organic amendments (fresh, compost, and vermicompost olive cake) on the soluble and diethylenetriamine pentaacetic acid (DTPA)–extractable lead (Pb) and zinc (Zn) and on different enzymatic activities in an artificially contaminated calcareous soil. Application of the compost and vermicompost, which increased amounts of humic acids in soil, initially stimulated dehydrogenase, s‐glucosidase, and urease activities, which tended to decline afterward. In contrast, dehydrogenase and s‐glucosidase activities were lower after application of the fresh olive cake. Amounts of soluble Pb and Zn increased when fresh olive cake was added to the soil, due to the high content of water‐soluble carbon in this amendment. On the contrary, application of the compost and vermicompost decreased the concentration of soluble Zn and did not change the soluble Pb levels in the soil. The DTPA‐Pb and DTPA‐Zn were scarcely affected by the ...

Ash derived from energy generation is used as a source of minerals in livestock feeds. The microbial biosensor recApr-Luc2 was built to detect genotoxic hazard in recycled ash. Escherichia coli SOS gene (recA, lexA, dinI and umuC) expression in response to cisplatin-induced DNA damage led to the selection of the recA promoter. The biosensor required functional RecA expression to respond to genotoxic heavy metals (Cr>Cd≈Pb), and polluted ash induced a strong recApr-Luc2 response. In human liver and intestinal cells, heavy metals induced acute toxicity (Cr>Cd>Pb) at concentrations sufficient to activate recApr-Luc2. Cytostatic effects, including genotoxicity, were cell- and metal-dependent, apart from Cr. In agreement with the recApr-Luc2 bioassay, Cr had the strongest effect in all cells. In conclusion, recApr-Luc2 could be useful for evaluating the genotoxic risk of pollutants present in ash that might be concentrated in animal products and, thus, entering the human food chain.

International audience; Soil organic amendment addition is an effective practice in Mediterranean areas due to its associated high agricultural benefits and its potential to reduce the pesticide impact on water resources. However, their metabolites have received scarce attention, even when they may pose more risk than their parent compounds. Two winery vermicomposts obtained from spent grape marc (V1) and the mixture vine shoot-biosolid vinasses (V2) have been investigated as low cost organic amendments to minimize the leaching of diuron, imidacloprid and their metabolites in columns packed with a sandy loam (S1) and a silty-clay loam soil (S2) under steady state flow conditions. In the unamended soil columns, leached amounts of diuron were 75% and 53% in S1 and S2, respectively. Its metabolites (3-(3,4-dichlorophenyl)-1-methylurea, DPMU; and 3,4-dichlorophenylurea, DPU) percolated less than 35% of the total applied amount. The amount of the metabolite 3,4-dichloroaniline (DCA) was 2% and 30% for S1 and S2, respectively. Leaching of imidacloprid was 79% and 96% for S1 and S2, respectively, while its metabolite 6-chloronicotinic acid (CNA) was entirely leached. In the vermicompost-amended columns, the leaching of diuron was reduced 2 to 3-fold. DPMU and DPU were also significantly reduced (more than 6-fold). DCA did not appear in any of the leachates of the amended soil columns. Imidacloprid leaching was reduced 1 to 2-folds in the amended columns. The amendments did not affect the transport of CNA. The dissolved organic carbon (DOC) from the vermicomposts did not enhance pesticide transport throughout the soil in any case. This qualitative study presents these vermicomposts as an effective potential low-cost tool in reducing pesticide and metabolite leaching. The next step would be to test them under more realistic conditions.

A greenhouse study was conducted to evaluate the potential use of olive-cake ash as a soil amendment, using pepper (Capsicum annuum, L. cv Italian sweet). Three soils of different pH (acidic, neutral and calcareous) were used. Treatments included a control (no fertilizer application), NPK fertilizer, and two ash-application rates that provided a complete dose (equivalent to the K2O amount in the fertilizer) and a half dose (equivalent to half the K2O amount in the fertilizer), respectively. The ash was effective in raising soil pH. Ash treatments increased the pepper (stems and leaves) dry matter yield over control; although these increases were lower than treatment including NPK. Application of ash significantly increased leaf P concentration and AB-DTPA extractable P in soil, especially in the acidic and neutral soils. Leaf K concentrations and readily and slowly available K forms in soils were affected positively by the addition of the ash. These results demonstrate that ash from the combustion of wet olive cake can be used as a beneficial organic soil amendment.

This work undertakes the biochemical characterization of olive-orchard soils cultivated under three different management systems: conventional, integrated, and organic. The orchards are located in two districts of Andalusia (S Spain): Pedroches Valley (Cordoba province) and Montes Orientales (Granada province). In each soil, the activities of various enzymes were determined – oxide reductases (dehydrogenase, o-diphenol oxidase), hydrolytic activities linked to the C- and P-cycles (β-glucosidase and phosphatase) and indolacetic acid production (auxins) – as were phenol concentrations, pH, and total organic carbon of the soil. The biochemical activity of the soils studied differed depending on the cultivation or weed–control system. The soils developed under organic management in general presented greater biological activity and greater hydrolytic activity than those under integrated or conventional cultivation. The data, processed by discriminant analysis, divided the soils into three well-differentiated groups. Of all the soils considered a priori as soils under organic management, 89% were classified as belonging to the same group, while the remaining 11% showed characteristics similar to those of the integrated management group. The discriminant analysis proved especially effective to differentiate olive-orchard soils treated with herbicides from those without such treatment; the fit between the soils considered as belonging to each of the weed–control systems and those predicted by the discriminant model was 100%. The biochemical response of the soil, therefore, differed according to the type of management, and this could be used as a possible control system of crops under organic cultivation.

The aim of this work was to study the use of organic wastes from olive oil (alperujo), winery, and alcohol industries (vine shoots, spent grape marc, lees cake, and biosolids vinasse) as sorbents f...

A laboratory experiment was conducted to evaluate the enzyme activities and chemical changes recorded in a recalcitrant phenolic-rich waste after treatment with Pleurotus ostreatus or Eisenia fetida. The waste used was wet olive cake (alperujo in Spanish), a waste produced in huge amounts by the olive oil industry. Both P. ostreatus and E. fetida were very effective in removing phenolic compounds, the initial concentration in the wet olive cake being reduced in both cases by around 90%. Laccase and manganese peroxidase activities were measured in the growth medium of P. ostreatus, and catechol 2,3 dioxygenase activity was only detected in the waste treated with Eisenia; these could be the main factors responsible for the oxidation of phenolic compounds. Increases of dehydrogenase and beta-glucosidase activities were detected in the degraded wet olive cake by fungi or earthworms. In comparison with the natural wet olive cake, the degraded products had lower total organic carbon and humic acid contents but were rich in nitrogen and other nutrients, having lower C:N ratios. In addition, the toxicity of the wet olive cake against the seeds of Lepidium sativum significantly decreased after degradation. The low toxicity as well as moderate stability and maturity recorded in the wet olive cake treated with P. ostreatus or E. fetida imply that these products could be used as soil amendments.

In Mediterranean countries, millions of tons of wastes from viticulture and winery industries are produced every year. This study describes the ability of the earthworm Eisenia andrei to compost different winery wastes (spent grape marc, vinasse biosolids, lees cakes, and vine shoots) into valuable agricultural products. The evolution of earthworm biomass and enzyme activities was tracked for 16 weeks of vermicomposting, on a laboratory scale. Increases in earthworm biomass for all winery wastes proved lower than in manure. Changes in hydrolytic enzymes and overall microbial activities during the vermicomposting process indicated the biodegradation of the winery wastes. Vermicomposting improved the agronomic value of the winery wastes by reducing the C:N ratio, conductivity and phytotoxicity, while increasing the humic materials, nutrient contents, and pH in all cases. Thus, winery wastes show potential as raw substrates in vermicomposting, although further research is needed to evaluate the feasibility of such wastes in large-scale vermicomposting systems.

The ability of a degraded soil to respond to successive additions of a toxic organic waste (olive-mill solid waste) and its vermicompost was studied in a controlled incubation experiment for 32 weeks. Hydrolytic enzyme activities (phosphatase, β-glucosidase), oxidoreductase activities (dehydrogenase, o -diphenol oxidase) and indole acetic acid production, were used as measures of soil perturbation. No microbial activity, indicated by the total lack of dehydrogenase activity, was detected when the olive-mill solid waste was added to the soil. However, after 16 weeks, the activity returned to the original soil levels (1.35 μg INTF g −1 h −1 ). The addition of vermicomposted olive-mill solid waste increased the original soil dehydrogenase activity by five-fold, indicating a loss of toxicity of the waste during the vermicomposting process; the activity remained high throughout the experiment. At week 21, a second addition of olive solid waste, was made to both olive waste and vermicompost-amended soils, when the soil originally amended with olive waste had reached the activity measured in soil amended with vermicompost. Dehydrogenase activity recovered immediately, reaching levels up to seven-fold higher than the background levels of the soil. The ability of soil to respond to a toxic waste clearly differed after a period of exposure to the waste. The faster response was probably related to the increased pool of stabilized organic matter present in soil, arising from the stabilization of added olive waste in the soil or through the amended vermicompost. The amplitude (period of recovery to the initial state after disturbance) and the elasticity (speed of recovery) of the soil could also be monitored by o -diphenol oxidase and β-glucosidase activities. However, indole-3-acetic acid production proved to be a useful measure of perturbation only following the second addition of the olive waste.

Se analizó la actividad de 4 enzimas del suelo en fincas bajo diferentes manejos agronómicos y en diferentes tipos de suelos. Las enzimasevaluadas fueron la Fosfatasa, β-Glucosidasa,Deshidrogenasa y Ureasa. Se tomaron muestras desuelo de los primeros 20 cm de profundidad conel fin de analizarlas químicamente y determinar laactividad de las 4 enzimas a evaluar. Se encontró que la actividad de la Deshidrogenasa varió de0,13 a 4,46 con un promedio de 1,17 (µg INTF.g¹.h-1); la β-Glucosidasa varió de 31,9 a 208,1con un promedio de 108,1 (µg PNP.g-1.h-1). Porotro lado la Fosfatasa tuvo valores entre 413,4 y3043,6 con un promedio de 1521,5 µg PNP.g-1.h-1,mientras que la Ureasa varió de 12,5 a 52,8 con un promedio de 38,3 µg N-NH4.g-1.h-1. La Fosfatasa correlacionó con el porcentaje de materia orgánica y de carbono en el suelo (0,75 y 0,76 respectivamente, p

Generally, the potential for biosolids (digested or composted)to contribute heavy metals to the soil-plant system has beencompared with commercial fertilizers and other organic wastesbut not with biosolids-ash. An column study was conducted in agreenhouse to determine the availability, extractability andleachability of metals in a degraded, non-calcareous soilamended with different biosolids (200 Mg ha-1). Thebiosolids investigated were dewatered, anaerobically digestedbiosolids, composted biosolids and biosolids-ash. The columns(26 cm) were planted with wheat (Triticum aestivum L. cvMexa). The addition of digested biosolids decreased the drymatter yield of wheat. Treatments including organic biosolidsincreased Cu and Zn concentrations in wheat roots, straw andgrain, whereas the addition of biosolids-ash did not affect theconcentrations of these metals in wheat. Concentrations of Ni,Co, Pb, Cr and Cd in wheat were below reliable detection limits(0.06, 0.05, 0.1, 0.06 and 0.02 mg kg-1, respectively).After harvesting, total and AB-DTPA extractable Cu, Zn and Pbincreased in the upper layer of the soil amended with thedifferent biosolids studied, whereas levels of AB-DTPAextractable Ni and Co were affected only when the soil wasamended with digested or composted biosolids. Total chromiumincreased only in treatments including organic biosolids. TheAB-DTPA extractable Cu, Zn and Pb in the lower layer of thesoil in treatments including biosolids evidenced downwardmovement of these metals. However, absence of these metals incolumn leachates indicates that this movement was gradual.

Dry olive cake, alone or mixed with biosolids or cattle manure, was used to assess the ecological management of a degraded soil. These olive by-products had been stabilised previously for 160 days in a vermicomposting process. Unprocessed and vermicomposted products were used as organic mulches in a greenhouse experiment. The control contained only degraded soil. Soil biochemical activities (dehydrogenase, urease and phosphatase) were studied in the rhizosphere of pepper (Capsicum annuum, L.). In addition, the changes in plant growth and nutrient content of C. annuum following addition of mulches were measured. The addition of dry olive cakes as organic mulches increased P concentration in pepper leaves from 1.5 to 4.5–5.7 g kg−1. Potassium concentration in leaves increased from 51 to 65–85 g kg−1, depending on the mulch assayed. In contrast, N concentrations were unaffected. Rhizosphere dehydrogenase activity increased by 1.5- to 2.5-fold by incorporation of mulches, either vermicomposted or not, when compared with the no-mulch control. This suggests that microbial numbers and potential activity in the rhizosphere were related to the addition of organic materials. Urease activity in the rhizosphere was inhibited, at least three-fold, when unprocessed products were used as organic mulches, but this inhibitory effect disappeared when unprocessed dry olive cakes were previously vermicomposted. Phosphatase activity was stimulated by the presence of organic mulches, especially if they were previously vermicomposted. Dry olive cake should be vermicomposted prior to use as mulching media in horticultural crops.

Vermicomposting is an eco-biotechnological process that transforms energy-rich and complex organic substances into a stabilized humus-like product. In a laboratory experiment, Eisenia fetida (Sav.) earthworms were employed to process putrescible sewage sludges into a high-value biofertilizer, very rich in urease activity and humic-urease complexes (stabilized extracellular enzymes). Extracellular humic-urease complexes were extracted by a single 24-h extraction at 37 °C using neutral pyrophosphate (0.1 M); then, the extracts were dialysed and characterized by means of an analytical isoelectric focusing technique. This technique gave a multiplicity of humic bands enzymatically active, with isoelectric points ranging from 4.8 to 5.6. The results demonstrated that, after an 18-week incubation period, sewage sludge had undergone a biochemical evolution, which caused a doubling of absolute urease activity and a six-fold increase in specific activity (activity with reference to the humic C fraction). The biochemical evolution of the vermicompost was evaluated also from the sharp decrease in pyrophosphate-extractable C and water-soluble C. Stabilization of organic C during vermicomposting and the activity of humic-urease complexes expressed at low pH values are of extreme importance when organic wastes are used in acid soils for biochemical restoration purposes.

A laboratory‐based incubation study was conducted to examine N mineralization/immobilization and C mineralization of both vermi‐composted and unprocessed dry olive cake when added to soil. Cattle manure and a soil‐only treatment were also examined. The organic amendments were mixed with soil at rates to add 1.5 times the soil C (soil C: 6.1 g/kg). The incubations were conducted at 28°C, and were sampled at intervals of 1, 7, 14, 28, 49, 70 and 91 days for the analysis of soil NH4 +‐N and NO3 ‐‐N, and soil respiration. The C to N ratios of the unprocessed olive cake, vermi‐composted olive cake and manure were 42, 29 and 11, respectively. Both the unprocessed olive cake and vermi‐composted olive cake immobilized soil N throughout the 91 days of the study. The cattle manure mineralized an appreciable amount of N during the study. The prolonged immobilization of soil N by the vermi‐composted olive cake was attributed to the C to N ratio of 29 and to the recalcitrant nature of its C and N composition....

The feasibility of vermicomposting pesticide contaminated refuses was evaluated. A mixture of sewage sludges was amended, at a ratio of 1:1 (v/v), with a garden refuse artificially contaminated with carbaryl, a carbamate insecticide commonly used in farming and gardening. Ten clitellated earthworms were then placed in this material. We determined the evolution of earthworm (Eisenia foetida, Savigny) biomass and changes in enzyme activities during an 18-wk period of sewage sludge vermicomposting. The carbaryl produced a chronically toxic effect on the earthworms, measured by weight gain and sexual maturity. The growth was slower in the presence of pesticide. In addition, carbaryl treatments showed inhibited enzyme activity in the first weeks of the vermicomposting process, slowing down organic matter biodegradation. The dynamics of the vermicomposting process can be followed by combining easily detectable parameters related to the global microbial metabolism: a traditional chemical (water-soluble C/water-soluble N) and biochemical (dehydrogenase activity/water-soluble C) index, were calculated. In particular, this last seemed more useful in characterizing the vermicomposting process even a longer maturation time (10-18 wk).

Evolution of earthworm (Eisenia foetida, Savigny) biomass and changes in enzyme activities during 18 weeks of sewage sludge vermicomposting were studied. With time, hydrolase (β-glucosidase, urease, BAA-hydrolysing protease and phosphatase) and dehydrogenase (DH-ase) activities decreased as available organic compounds (water-soluble carbon) decreased. A high correlation among all enzyme activities and between each activity and the water-soluble carbon (WSC) led to the conclusion that both hydrolytic and dehydrogenase activities could be feasible indicators of the state and evolution of the organic matter. The ‘potential metabolic index’ (DH-ase/WSC) enabled distinguishing between hydrolytic and maturation phases in a sewage sludge vermicomposting process.

We studied vermicomposting with Eisenia andrei of sludges from a paper mill mixed with cattle manure in a six-month pilot-scale experiment. Initially, a small-scale laboratory experiment was carried out to determine the growth and reproduction rates of earthworms in the different substrates tested. In the pilot-scale experiment, the number of earthworms increased between 22- and 36-fold and total biomass increased between 2·2- and 3·9-fold. The vermicomposts were rich in nitrogen and phosphorus and had good structure, low levels of heavy metals, low conductivity, high humic acid contents and good stability and maturity. These sludges could be potentially useful raw substrates in larger commercial vermicomposting systems, and would reduce the costs related with the exclusive use of different types of farm wastes as feed for earthworms.

A greenhouse experiment using soil was conducted to investigate the effects of the addition of different forms of either nickel or lead, together with an acidifying agent, on the distribution of Ni, Pb, Zn, Cu and Mn in wheat plants, and on the post-harvest extractability of these elements in the soil. Two treatments consisting of soil alone or soil mixed with sewage sludge at a rate of 200 Mg ha−1 were used as controls. Nickel (400 mg kg−1) or lead (1600 mg kg−1) was added to the soil as an inorganic salt or mixed previously with sewage sludge. Six further treatments including an acidifying agent (wastewater from olive oil processing: alpechin) were also prepared. Wheat (Triticum aestivum L. var. Mesa) plants were harvested 75 d after germination. Dry matter yield of wheat was increased by the addition of sewage sludge. No reductions in yield were observed after the addition of nickel or lead. Nickel concentration and uptake by wheat, and extractability from soil, were higher when the sewage sludge enriched in nickel was added to soil. This effect was enhanced when the acidifying agent was also added. In contrast, lead availability was higher after the addition of inorganic Pb to soil. The addition of both forms of Ni enhanced Zn, Cu and Mn uptake by the plant, whereas the addition of lead increased Zn and Cu. After harvesting, increases in extractable Zn and Cu in the soil were observed only in treatments with sewage sludge, and not after the addition of Ni or Pb, or after the addition of the acidifying agent. Decreasing the pH of the soil with the acidifying agent tended to increase Mn uptake by wheat, and Mn extractability from the soil after harvesting.