Search results for "SOLIDS"
showing 10 items of 159 documents
Impact de l'épandage des boues sur le phosphore dissous et particulaire des écoulements de surface
2003
Abstract The aim of this study was to assess the effect of land application of sewage sludge on phosphorus (P) losses during intense rainfall. Three rainfall simulations (40 mm h−1 of 30 min duration) were conducted on a field amended with sewage sludge. The overland flow water (OFW) was monitored and sampled every minute. The suspended solid, the dissolved and total phosphorus (respectively SS, TP and DP) concentrations were analysed. The forms of particulate bound P (PP) were investigated. Several results stem from this experiment: (a) sludge application induced a large increase in the DP content of the OFW; the concentrations obtained (0.15–0.57 mg l−1) were shown to result from desorpti…
Modelling hydrolysis: Simultaneous versus sequential biodegradation of the hydrolysable fractions
2018
Hydrolysis is considered the limiting step during solid waste anaerobic digestion (including co-digestion of sludge and biosolids). Mechanisms of hydrolysis are mechanistically not well understood with detrimental impact on model predictive capability. The common approach to multiple substrates is to consider simultaneous degradation of the substrates. This may not have the capacity to separate the different kinetics. Sequential degradation of substrates is theoretically supported by microbial capacity and the composite nature of substrates (bioaccessibility concept). However, this has not been experimentally assessed. Sequential chemical fractionation has been successfully used to define i…
Disintegration of Wastewater Activated Sludge (WAS) for Improved Biogas Production
2018
Due to rapid urbanization, the number of wastewater treatment plants (WWTP) has increased, and so has the associated waste generated by them. Sustainable management of this waste can lead to the creation of energy-rich biogas via fermentation processes. This review presents recent advances in the anaerobic digestion processes that have led to greater biogas production. Disintegration techniques for enhancing the fermentation of waste activated sludge can be apportioned into biological, physical and chemical means, which are included in this review; they were mainly compared and contrasted in terms of the ensuing biogas yield. It was found that ultrasonic- and microwave-assisted disintegrati…
Aerobic composting and anaerobic digestion of pulp and paper mill sludges
1997
The feasibility of aerobic vessel composting and anaerobic digestion for the treatment of pulp and paper mill sludges were studied. The composting studies made use of primary and secondary sludge from a de-inking and paper mill. In six parallely aerated 500 1 vessels with various carbon : nitrogen (C:N) -ratios, the most optimal performance was obtained with C:N -ratios of c. 22–35, while higher and lower ratios delayed the temperature increase. With the optimal ratios, the thermophilic stage was reached within 36 h, and the stage lasted for about seven days. In the scale-up study (18 m3 compost vessel), the thermophilic stage was reached within 24 h. An effective dehydratation of the mass …
The Influence of Fruit Ripening Stage at Harvest and Storage Temperature on ‘Bianca di Bivona’ White Flesh Peaches
2015
‘Bianca di Bivona’ is a white-flesh peach cultivar, which ripens during the last week of July and the first of August. Its fruit are known because of their distinct flavor and aroma, which make them highly accepted, particularly in the local markets. However, nothing is known about their postharvest physiology and storage conditions. In order to investigate the effect of: (a) fruit ripening stage at harvest and, (b) storage temperatures, ‘Bianca di Bivona’ peaches were picked at mature-green, (60.0±1.3 N), and ripe stage (30.7 ± 2.1 N) determined by flesh firmness, and then stored at 0°C and 5°C (90% RH). Flesh firmness, total soluble solids, titratable acidity, weight loss and DA index, me…
Fruit Quality Traits of Two Apricot Cultivars
2010
In this trial we evaluated physical and chemical fruit quality traits and sensory profile of two late-ripening apricot cultivars ‘Vitillo’ and ‘Pellecchiella’. Fruits were harvested at full maturation in three different pickings, at 4 day intervals, to ensure the same fruit quality. To verify quality among different pickings, weight, diameter, soluble solid content, titratable acidity, pH, colour were recorded. To describe and quantify the sensory characteristics of apricot fruits a panel of 10 judges generated 16 descriptors. For each of these attributes judges assigned a score from 1 to 9. Qualitative and sensory data for each attribute were submitted to one way Analysis of Variance (ANOV…
Correlation of wood-based components and dewatering properties of waste activated sludge from pulp and paper industry.
2010
Large amounts of wet sludge are produced annually in municipal and industrial wastewater treatment. Already in pulp and paper industry, more than ten million tons of primary sludge, waste activated sludge, and de-inking sludge is generated. Waste activated sludge contains large quantities of bound water, which is difficult to dewater. Low water content would be a matter of high calorific value in incineration but it also has effects on the volume and the quality of the matter to be handled in sludge disposal. In this research waste activated sludges from different pulp and paper mills were chemically characterised and dewatered. Correlations of chemical composition and dewatering properties…
Effect of Drying Condition on the Quality of Dry Late Peaches of Leonforte
2015
The Late Peach of Leonforte [Prunus persica (L.) Batsch] grown in Southern Italy matures in September and October and as late as November. Fruits are wrapped in paper bags to protect them from parasites and are harvested only when fully ripe. Protected inside the bags, they ripen late and take on a bright yellow colour with red streaks. Highly aromatic, the peach has yellow, firm flesh that is high in soluble solids and has a distinctive, slightly caramelized flavour. The aim of this work was to deter¬mine the best method of drying peach as a means of conserving the fruit after harvest due to its very limited shelf-life. Drying processes were carried out in a pilot plant utilising differen…
Factors controlling hydrochemical and trophic state variables in 86 shallow lakes in Europe
2003
In order to disentangle the causes of variations in water chemistry among European shallow lakes, we performed standardised sampling programs in 86 lakes along a latitudinal gradient from southern Spain to northern Sweden. Lakes with an area of 0.1 to 27 000 ha and mean depth of 0.4–5.6 m located in low to high altitudes were investigated within the EC project ECOFRAME 1–4 times during June–October 2000–2001. Several variables like conductivity, alkalinity, abundance of submerged plants, concentrations of suspended solids, total nitrogen and phosphorus were latitude-dependent decreasing from south to north. Secchi depth, concentrations of total nitrogen, total phosphorus, suspended solids, …
Normal pressures and frictional tractions on shallow conical hopper walls after concentric filling: Predictions and experiments
2013
Author's version of an article in the journal: Chemical Engineering Science. Also available from the publisher at: http://dx.doi.org/10.1016/j.ces.2012.11.028 A silo with a shallow hopper is designed to achieve the required silo capacity when the headroom available is limited, provided that the issue of segregation of stored particulate solids is not a problem. Several analytical models have been proposed to try to predict the design loads for such shallow silo hoppers to guarantee their structural integrity. In this study, a novel finite element analysis has been conducted to explore the development of pressures and tractions on the wall of a full scale shallow hopper when it is filled wit…