Nitrogen mineralization from digestate in comparison to sewage sludge, compost and urea in a laboratory incubated soil experiment

This paper evaluated, in a laboratory incubated soil, the properties of digestate as a nitrogen fertilizer in comparison with sewage sludge, compost and urea, this last as a typical mineral fertilizer. The incubation period lasted for 90 d and during this time, pH, CO2 and NO3 - evolution were measured. The maximum concentration of nitrate was reached in the incubated microcosm fertilized by urea (133 mg kg-1 after 62 d), and that of digestate was very similar (113 mg kg-1). Soil treated with compost showed a slower nitrate evolution. A significantly negative correlation was detected between cumulative nitrogen nitrified at the end of the trial, and the values of the C:N ratio of the biomasses used (compost, sludge and digestate) (mg kg-1 N - NO3 - vs. C:N, r=-0.94, n = 3, p < 0.05), and between the alkyl-C content at the end of the experiment (mg kg-1 N - NO3 - vs. alkyl-C, r = -0.95, n = 3, p < 0.05). As expected, pH decreases and soil respiration (CO2 evolution) were also well correlated with the content of nitrate. Considering that about 90% of the nitrogen content in the digestate is short acting, the results obtained indicate that the nitrogen rate of mineralization in digestate is very similar to that of urea, confirming that digestate could replace traditional mineral fertilizers

Humic acid formation in artificial soils amended with compost at different stages of organic matter evolution

A composting process was conducted under optimal conditions for 150 d, obtaining three biomasses at different levels of maturity: raw material (RM), fresh compost obtained after 11 d of composting (FC), and evolved compost (EC) obtained after 150 d of composting. During the composting process, HAs were extracted and fully characterized by mass balance, DRIFT, and 1H and 13C-nuclear magnetic resonance spectroscopy. Each compost sample was incubated for 180 d in an artificial soil, after which HA extraction was repeated and characterized. To compare composts containing different amounts of labile organic matter (OM), an equal amount of unhydrolyzable OM was added to the soils. Our results indicated that compost HAs consist of a biologically and chemically stable fraction (i.e., the unhydrolyzable HA [U-HA]) and a labile fraction, whose relative contents depended on the composting duration. Humic acid from more EC contained a higher amount of recalcitrant fraction (aromatic carbon) and a lesser amount of labile fraction (aliphatic carbon) than HA from RM and FC. These results suggest that the humification process during composting preserves the more recalcitrant fraction of the compost-alkali soluble/acid insoluble fraction (HA-fraction). Incubation of composts in soil showed that due to the higher labile fraction content, HAs from raw material were more degraded than those from EC. The abundance of labile carbon of soil amended with less-evolved compost (RM and FC) allowed the more recalcitrant fractions of U-HA to be more preserved than in EC. These results suggest that less-evolved compost could contribute more than well evolved compost to the stable soil OM. Copyrigh

Effect of compost application rate on carbon degradation and retention in soils

We investigated the effect of a single compost application at two rates (50 and 85 Mg ha-1) on carbon (C) degradation and retention in an agricultural soil cropped with maize after 150 d. We used both C mass balance and soil respiration data to trace the fate of compost C. Our results indicated that compost C accumulated in the soil after 150 d was 4.24 Mg ha-1 and 6.82 Mg C ha-1 for 50 and 85 Mg ha-1 compost rate, respectively. Compost C was sequestered at the rate of 623 and 617 g C kg-1 compost TOC for 50 and 85 Mg ha-1 compost dose, respectively. These results point to a linear response between dose of application and both C degradation and retention. The amount of C sequestered was similar to the total recalcitrant C content of compost, which was 586 g C kg-1 compost TOC, indicating that, probably, during the short experiment, the labile C pool of compost (414 g C kg-1 of compost TOC) was completely degraded. Soil respiration measured at different times during the crop growth cycle was stable for soils amended with compost (CO2 flux of 0.96 ± 0.11 g CO2 m-2 h-1 and 1.07 ± 0.10 g CO2 m-2 h-1, respectively, for 50 and 85 Mg ha-1), whereas it increased in the control. The CO2 flux due to compost degradation only, though not statistically significant, was always greatest for the highest compost doses applied (0.22 ± 0.40 g CO2 m-2 h-1 and 0.33 ± 0.25 g CO2 m-2 h-1 for the 50 and 85 Mg ha-1 compost dose, respectively). This seems to confirm the highest C degradation for the 85 Mg ha-1 compost dose as a consequence of the presence of more labile C. Unlike other studies, the results show a slight increase in the fraction of carbon retained with the increase in compost application rate. This could be due to the highly stable state of the compost prior to application, although it could also be due to sampling uncertainty. Further investigations are needed to better explain how the compost application rate affects carbon sequestration, and how characterization into labile and recalcitrant C can predict the amount of C sequestered in the soil

Kualitas Penggunaan Antibiotik Pada Pasien Bedah Digestif Di Rsup Dr Kariadi Semarang

Background: Inapropiate use of antibiotic results in antibiotic resistance. Most antibiotic USAge in hospital is in surgery patients. This study was conducted to determine the quality USAge of antibiotic in digest-surgery patients in Kariadi hospital in July-December 2014.Method:This study used descriptive design with medical records of digestive surgery patients who used antibiotic in July-December 2014. Medical records that were obtained by random (simple random sampling) method, analyzed by Gyssens category.Results: There were 106 prescriptions from 36 medical records. The most USAge antibiotics are ceftriaxone, cefadroxil, and ciprofloxacin. The assessment of Gyssens's method showed that 16% were classified as rational use. 5,7% were irrational caused by too long USAge (IIIA), 0,9% irrational caused by too short timing, 23,6% irrational caused by there are narrower spectrum (IVD), 51,9% unknown indication (V), and 1,2% cannot be analyzed (VI). The type of therapy were reviewed as ADE (17,9%), ADET (0,9%), ADP (27,4%), and ADU (51,9%).Conslusion :Quality of antibiotic use in digestive surgery ward based on Gyssens is mostly irrationa

Biological Compost Stability Influences Odor Molecules Production Measured by Electronic Nose During Food-Waste High-Rate Composting

Composting is a technique that is used to convert organic waste into agriculturally useful products. Composting is an aerobic, solid-state biological process, which typically can be divided into two phases, a high-rate composting phase and a curing phase. High-rate composting plays an important role during the composting process, owing to the high microbial activity occurring during this phase. It requires an accurate plant design to prevent the formation of anaerobic conditions and odors. The formation of anaerobic conditions mainly depends on the rate of O2 consumption needed to degrade the substrate, i.e., the biological stability of the substrate. In this study, we investigated the relationship between the biological activity, measured by the dynamic respiration index (DRI) and the odor molecules production, measured by an electronic nose (EN) during two food-waste high-rate composting processes. Although the O2 concentration in the biomass free air space (FAS) was kept optimal (O2 > 140\ua0ml l- 1, v/v) during composting, strong anaerobic conditions developed. This was indicated by the high levels of sulfur compounds, methane, and hydrogen in the outlet air stream. Both the high level of O2 consumption, needed to degrade the high-degradable water-soluble organic matter and the low water O2 solubility, caused by high temperature reached in this stage (up to 60\ua0\ub0C), led to the anaerobic conditions observed in the biofilm-particle level. The application of the partial least square (PLS) analysis demonstrated a good regression between the DRI and the odor molecules produced that was detected by the EN (R2 = 0.991; R2CV = 0.990), signifying the usefulness of the DRI as a parameter to estimate the potential production of odor molecules of the biomass

Evaluation of total and bioavailable heavy metals and other soilrelated variables in a rice paddy after the application of defecation lime

A two-year experiment was carried out in a paddy field to investigate the effects of the use of defecation lime derived from treated sewage sludge on soil total and soil phytoavailable heavy metals concentration. Heavy metals concentration was determined also in raw rice. Four treatments were arranged in a completely randomized block design: not fertilised (T0), organic fertilisation + chemical fertilisers (T1), defecation lime + chemical fertilisers (T2), defecation lime at pre-sowing (T3). For T3, the pH value increased significantly at the end of the second year, increasing from 5.8 to 6.11. T3 resulted in the highest soil organic carbon content (9.4 g kg-1), suggesting the potential of defecation lime both as soil corrective material and soil amendment. The application of defecation lime in the paddy field did not result in an increased phytoavailable amount of heavy metals in soil

Utilization of centrate from wastewater treatment for the outdoor production of Nannochloropsis gaditana biomass at pilot-scale

In this work, the outdoor pilot-scale production of marine microalga Nannochloropsis gaditana using centrate from the anaerobic digestion of municipal wastewater was evaluated. For this, outdoor continuous cultures were performed in both tubular and raceways reactors mixing seawater with different centrate percentages (15%, 20% and 30%) as culture medium. It was demonstrated that N. gaditana can be produced using centrate as the only nutrients source but at percentages below 30%. At this level inhibition was caused by an excess of ammonium in both photobioreactors, as confirmed by chlorophyll fluorescence and average irradiance data, thus reducing productivity. At 15% and 20% centrate percentages, biomass productivity was equal to that measured when using Algal culture medium, of 0.48 and 0.10 g·l-1·day-1 for tubular and raceway reactors respectively. During the experiments nitrogen depuration decreased from 85% to 63% in tubular reactors with the increase of centrate percentage in culture medium and the decrease in biomass productivity, while in raceway reactors an opposite behavior was observed due to ammonia stripping from the cultures. Phosphorus depuration from the culture medium was 85% whatever the system used and the centrate percentage in culture medium indicating a phosphorus limitation into the cultures. By supplying additional phosphorus, to achieve an N:P ratio of 5, it was possible to enhance productivity and increase nitrogen depuration in both systems. The use of centrate is confirmed as a useful method for reducing microalgae production costs and for increasing process sustainability. Consequently, it is demonstrated that for the production of microalgae biomass, centrate from wastewater treatment plants can be used as the exclusive nutrient source, achieving high productivities and nutrient removal rates if using suitable strains and if the system is operated adequately

Assessing amendment properties of digestate by studying the organic matter composition and the degree of biological stability during the anaerobic digestion of the organic fraction of MSW

The transformation of organic matter during anaerobic digestion of mixtures of energetic crops, cow slurry, agro-industrial waste and organic fraction of municipal solid waste (OFMSW) was studied by analysing different samples at diverse points during the anaerobic digestion process in a full-scale plant. Both chemical (fiber analysis) and spectroscopic approaches ((13)C CPMAS NMR) indicated the anaerobic digestion process proceeded by degradation of more labile fraction (e.g. carbohydrate-like molecules) and concentration of more recalcitrant molecules (lignin and non-hydrolysable lipids). These modifications determined a higher degree of biological stability of digestate with respect to the starting mixture, as suggested, also, by the good correlations found between the cumulative oxygen uptake (OD(20)), and the sum of (cellulose + hemicellulose + cell soluble) contents of biomasses detected by fiber analysis (r = 0.99; P < 0.05), and both O-alkyl-C (r = 0.98; P < 0.05) and alkyl-C (r = -0.99; P < 0.05) measured by 13C CPMAS NMR