Treatment of digestate from a co-digestion biogas plant by means of vacuum evaporation: Tests for process optimization and environmental sustainability

Vacuum evaporation consists in the boiling of a liquid substrate at negative pressure, at a temperature lower than typical boiling temperature at atmospheric conditions. Condensed vapor represents the so called condensate, while the remaining substrate represents the concentrate. This technology is derived from other sectors and is mainly dedicated to the recovery of chemicals from industrial by-products, while it has not been widely implemented yet in the field of agricultural digestate treatment. The present paper relates on experimental tests performed in pilot-scale vacuum evaporation plants (0.100 and 0.025m3), treating filtered digestate (liquid fraction of digestate filtered by a screw-press separator). Digestate was produced by a 1MWe anaerobic digestion plant fed with swine manure, corn silage and other biomasses. Different system and process configurations were tested (single-stage and two-stage, with and without acidification) with the main objectives of assessing the technical feasibility and of optimizing process parameters for an eventual technology transfer to full scale systems. The inputs and outputs of the process were subject to characterization and mass and nutrients balances were determined. The vacuum evaporation process determined a relevant mass reduction of digestate. The single stage configuration determined the production of a concentrate, still in liquid phase, with a total solid (TS) mean concentration of 15.0%, representing, in terms of mass, 20.2% of the input; the remaining 79.8% was represented by condensate. The introduction of the second stage allowed to obtain a solid concentrate, characterized by a content of TS of 59.0% and representing 5.6% of initial mass. Nitrogen balance was influenced by digestate pH: in order to limit the stripping of ammonia and its transfer to condensate it was necessary to reduce the pH. At pH 5, 97.5% of total nitrogen remained in the concentrate. This product was characterized by very high concentrations of total Kjeldhal nitrogen (TKN), 55,000. mg/kg as average. Condensate, instead, represented 94.4% of input mass, containing 2.5% of TKN. This fraction could be discharged into surface water, after purification to meet the criteria imposed by Italian regulation. Most likely, condensate could be used as dilution water for digestion input, for cleaning floor and surfaces of animal housings or for crop irrigation. The research showed the great effectiveness of the vacuum evaporation process, especially in the two stage configuration with acidification. In fact, the concentration of nutrients in a small volume determines easier transportation and reduction of related management costs. In full scale plants energy consumption is estimated to be 5-8kWhe/m3 of digestate and 350kWht/m3 of evaporated water

In retinal vein occlusion platelet response to thrombin is increased

INTRODUCTION: Retinal vein occlusion is a major cause of ocular morbidity. The precise mechanism leading to thrombosis in retinal vein occlusion has not yet been clearly elucidated. Several risk factors have been identified, including hypertension diabetes, history of cardiovascular disease, hypercholesterolemia, hyperhomocysteinaemia, increased ocular pressure and glaucoma. Although thrombus formation in the vein plays a significant role in the onset of retinal vein occlusion, the relationship between platelet aggregation and retinal vein occlusion remains to be clarified. MATERIALS AND METHODS: In the present study the platelet response to thrombin in a selected group of retinal vein occlusion patients was investigated. Retinal vein occlusion patients were compared to a group of healthy subjects matched for age, sex, clinical and metabolic characteristics. In resting and activated platelets of both groups of subjects total protein tyrosine phosphorylation, p38MAPK and cytosolic phospholipase A(2) phosphorylation, arachidonic acid release, intracellular calcium levels, thromboxane B(2) and superoxide anion formation were measured. RESULTS: Results show that platelets of patients were more responsive to thrombin than healthy subjects. In resting or in thrombin stimulated platelets of patients total protein tyrosine phosphorylation, p38MAPK and cytosolic phospholipase A(2) phosphorylation were increased. Also arachidonic acid release, thromboxane B(2) and superoxide anion formation were higher in patients than in healthy subjects. In addition intracellular calcium rise induced by thrombin was increased in patients. CONCLUSIONS: Altogether data suggest that platelet hyperaggregability inducing thrombus formation might be an important factor in the onset and/or development of retinal vein occlusion

Hypericum perforatum and neem oil for the management of acute skin toxicity in head and neck cancer patients undergoing radiation or chemo-radiation: A single-arm prospective observational study

Background: Radiation dermatitis is common in patients treated with combined radiotherapy and chemotherapy for head and neck malignancies. Its timely and adequate management is of uttermost importance for both oncological outcomes and global quality of life. We prospectively evaluated the role of hypericum perforatum and neem oil (Holoil®; RIMOS srl, Mirandola, Italy) in the treatment of acute skin toxicity for patients undergoing radiotherapy or chemo-radiotherapy for head and neck cancer. Methods: A consecutive series of 28 head and neck cancer patients submitted to radiotherapy (RT) was enrolled onto this mono-institutional single-arm prospective observational study. Patients undergoing both definitive or post-operative radiotherapy were allowed, either as exclusive modality or combined with (concomitant or induction) chemotherapy. We started Holoil treatment whenever bright erythema, moderate oedema or patchy moist desquamation were observed. Holoil® was used during all RT course and during follow up time, until acute skin toxicity recovery. Results: The maximum detected acute skin toxicity was Grade 1 in 7% of patients, Grade 2 in 68%, Grade 3 in 25%, while at the end of RT was Grade 0 in 3.5%, Grade 1 in 32%, Grade 2 in 61%, Grade 3 in 3.5%. For patients having G2 acute skin toxicity, it mainly started at weeks 4-5; for those having G3, it began during weeks 5-6. Median times spent with G2 or G3 toxicity were 17.5 and 11 days. Patients having G2 acute skin toxicity had a dermatitis worsening in 27% of case (median occurrence time: 7 days). G3 events were reconverted to a G2 profile in all patients (median time: 7 days). Those experiencing a G2 skin event were converted to a G1 score in 23% of cases (median time: 14 days). Time between maximum acute skin toxicity and complete skin recovery after RT was 27 days. Conclusions: Holoil® proved to be a safe and active option in the management of acute skin toxicity in head and neck cancer patients submitted to RT or chemo-radiotherapy. A prophylactic effect in the prevention of moist desquamation may be hypothesized for hypericum and neem oil and need to be tested within a prospective controlled study