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Humic-like substances obtained by alkaline hydrolysis of composted organic wastes are known to improve plant productivity. Little is known concerning the effect on plant growth of hydrolysates obtained by alkaline treatment of non-composted vegetal residues.The aim of this study was to prepare, characterize, and apply in horticulture the soluble and the insoluble fractions obtained by alkaline hydrolysis of exhausted tomato plants. The hydrolysates were prepared in a pilot plant from the tomato plants residue in powder form and characterized by solid state 13C NMR spectrometry, elemental analysis and potentiometric titration. The characterization of the soluble hydrolysate gave evidence of lignin and hemicellulose moieties, together with protein, peptide or amino acids while most of the cellulose was found in the insoluble fraction. Plant beans were grown on a peat and sand substrate fertilized with low application rate of the tomato plant powder and of the corresponding hydrolysates. The effect on bean plants was assessed by determination of plant growth, chlorophyll content, nitrate reductase, glutamine synthetase, glutamate synthase activities and soluble proteins.The tomato plant powder had no effect on all parameters measured on the grown bean plants. On the contrary, the insoluble and soluble substances sourced by alkaline hydrolysis of the tomato plant powder exhibit strong effects, mainly the increase of nitrogen assimilation typical of biostimulants.The results suggest that residual plant biomasses are source of efficient biostimolant and propose the hydrolysis of residual biomass as a viable profitable process to contribute important improvements also for waste management practices. © 2014 Elsevier B.V

The microwave assisted hydrolysis of urban biowaste fermented material to added value soluble lignin-like substances occurs with similar yields as, but in much shorter time than by, conventional heating.

Blends were obtained from poly(vinyl alcohol-co-ethylene) and water-soluble biopolymers isolated from the alkaline hydrolysate of two materials sampled from an urban waste treatment plant: that is, an anaerobic fermentation digestate and a compost. The digestate biopolymers contained more lipophilic and aliphatic C and less acidic functional groups than the compost biopolymers. Evidence was obtained for a condensation reaction occurring between the biopolymers and the synthetic polymer. The thermal, rheological, and mechanical properties of the blends were studied. Films containing a low concentration (ca. 6-7%) of biopolymers exhibited up to three times higher yield strength than the neat synthetic polymer. The films' properties were found to be dependent on the concentration and nature of the biopolymers. The results offer a scope for investigating biopolymers sourced from other biowastes and for a better understanding of the reasons for the observed effects and exploiting their full potential for modifying or replacing synthetic polymers.

Two hydrolysates obtained from anaerobic digestate and compost of a municipal bio‐waste treatment plant have been ozonizated at room temperature. This reaction yields two main products: biopolymers (30 % yield) whith molecular weights ranging from 100 to over 750 kDa, exhibiting remarkable surfactant properties, and small molecules with molecular weight ≤0.2⊥⊥kDa. The ozonised biopolymers have significantly different molecular weight distribution and much better surfactant properties compared to the pristine biopolymers. Their potential market value is estimated from 1.5 to 150 € kg−1 by comparison with commercial products. The small molecules are the bio‐based counterpart of commercial chemicals obtained from fossil sources. Their market value ranges from 0.6 to 3 € kg−1. Perspectives are discussed for the development of a bio‐based chemical industry built on the integration of biochemical and mild chemical technologies to convert biomass to value added products, and compared to the current model based on biochemical technology coupled to lignin incineration or pyrolysis.

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Soluble biobased lignin‐like polymeric substances (SBO) isolated from the alkaline hydrolysates of composted biowastes are promising chemical auxiliaries for multiple uses. They have good surfactant properties. Their black color spoils their performance in detergency and dyeing. Ozonization of SBO is reported now to yield bleached biosurfactants with improved performance. The work was performed, with SBO obtained from composted gardening residues, alone or mixed with kitchen wastes. They were dissolved in water at 3.3 % concentration. Oxygen containing 4 mol/mol % ozone was flown at 60 L h−1 for 48 h through the SBO solution. The crude ozonized products in ca. 80 % yield were filtered through different molecular cut off membranes and characterized for chemical features, molecular weight, and surface tension in water. The ozonized fractions with 200–500 kDa molecular weights accounted for 12–29 % of the total ozonized fractions's organic matter. They lowered water surface tension to 48–52 mN m−1. The lower molecular weight ozonized fractions had no surfactant activity, but their molecular features suggest other potentially valuable uses.

This study focused on the dissipation of propanil and 3,4 dichloroaniline (3,4 DCA) over time in the soil, field water, inlet water, and outlet water of paddy fields under three management systems: conventional water seeding (CON), conventional water seeding with supplied liquid manure (LMA), and dry seeding (DRY). Propanil dissipation in water was also investigated under laboratory conditions. The field study was conducted from 2004 to 2006 at Vercelli, northern Italy. Propanil and 3,4 DCA showed rapid dissipation in water and soil environments both in the field and in the laboratory. Under controlled conditions, chemical hydrolysis was not detected for either compounds for up to 100 d at pHs of 5, 7, and 9. In the laboratory, the half-life of propanil in irrigation water was 1.1 d; its half-life in soil was routinely measured at <1.0 d (between 0.17 and 1.77 d). 3,4 DCA was found to persist much longer. Measured in all three study years at 50 d after treatment, its concentration ranged between 44 μg kg (CON) and 140 μg kg (DRY). Propanil and 3,4 DCA concentrations in paddy water were particularly high in samples collected at 4 d (2004) and 2 d (2005) after treatment. Maximum concentrations were 54.4 μg L (CON) for propanil (2005) and 113.7 μg L (LMA) for 3,4 DCA (2004). The concentrations of propanil and 3,4 DCA in inlet water were never above 1.1 and 0.3 μg L, respectively, whereas the highest concentration of each compound in outlet water was in samples collected first after treatment in 2005 and 2006. Both chemicals dissipated rapidly in all the soil-water environments but displayed no important differences among the three management systems. In conclusion, propanil and 3,4 DCA did not persist longer in paddy fields. A risk of water network contamination by these compounds may occur only early after herbicide spraying. A water-holding period after herbicide spraying may reduce this risk.