Complete long-term monitoring of greenhouse gas emissions from a full-scale industrial wastewater treatment plant with different cover configurations.

The greenhouse gas (GHG) emissions from wastewater treatment plants (WWTPs), consisting mainly of methane (CH4) and nitrous oxide (N2O), have been constantly increasing and become a non-negligible contributor towards carbon neutrality. The precise evaluation of plant-specific GHG emissions, however, remains challenging. The current assessment approach is based on the product of influent load and emission factor (EF), of which the latter is quite often a single value with huge uncertainty. In particular, the latest default Tier 1 value of N2O EF, 0.016 ± 0.012 kgN2O-N kgTN-1, is estimated based on the measurement of 30 municipal WWTPs only, without involving any industrial wastewater. Therefore, to resolve the pattern of GHG emissions from industrial WWTPs, this work conducted a 14-month monitoring campaign covering all the process units at a full-scale industrial WWTP in Shanghai, China. The total CH4 and N2O emissions from the whole plant were, on average, 447.7 ± 224.5 kgCO2-eq d-1 and 1605.3 ± 2491.0 kgCO2-eq d-1, respectively, exhibiting a 5.2- or 3.9-times more significant deviation than the influent loads of chemical oxygen demand (COD) or total nitrogen (TN). The resulting EFs, 0.00072 kgCH4 kgCOD-1 and 0.00211 kgN2O-N kgTN-1, were just 0.36% of the IPCC recommended value for CH4, and 13.2% for N2O. Besides, the parallel anoxic-oxic (A/O) lines of this industrial WWTP were covered in two configurations, allowing the comparison of GHG emissions from different odor control setup. Unit-specific analysis showed that the replacement of enclosed A/open O with enclosed A/O reduced the CH4 EF by three times, from 0.00159 to 0.00051 kgCH4 kgCOD-1, and dramatically decreased the N2O EF by an order of magnitude, from 0.00376 to 0.00032 kgN2O-N kgTN-1, which was among the lowest of all full-scale WWTPs.

Endoscopic versus minimally invasive surgical approach for infected necrotizing pancreatitis: a systematic review and meta-analysis of randomized controlled trials.

BACKGROUND/AIMS: Acute pancreatitis is a common condition of the digestive system, but sometimes it develops into severe cases. In about 10-20% of patients, necrosis of the pancreas or its periphery occurs. Although most have aseptic necrosis, 30% of cases will develop infectious necrotizing pancreatitis. Infected necrotizing pancreatitis (INP) requires a critical treatment approach. Minimally invasive surgical approach (MIS) and endoscopy are the management methods. This meta-analysis compares the outcomes of MIS and endoscopic treatments. METHODS: We searched a medical database until December 2022 to compare the results of endoscopic and MIS procedures for INP. We selected eligible randomized controlled trials (RCTs) that reported treatment complications for the meta-analysis. RESULTS: Five RCTs comparing a total of 284 patients were included in the meta-analysis. Among them, 139 patients underwent MIS, while 145 underwent endoscopic procedures. The results showed significant differences (p < 0.05) in the risk ratios (RRs) for major complications (RR: 0.69, 95% confidence interval (CI): 0.49-0.97), new onset of organ failure (RR: 0.29, 95% CI: 0.11-0.82), surgical site infection (RR: 0.26, 95% CI: 0.07-0.92), fistula or perforation (RR: 0.27, 95% CI: 0.12-0.64), and pancreatic fistula (RR: 0.14, 95% CI: 0.05-0.45). The hospital stay was significantly shorter for the endoscopic group compared to the MIS group, with a mean difference of 6.74 days (95% CI: -12.94 to -0.54). There were no significant differences (p > 0.05) in the RR for death, bleeding, incisional hernia, percutaneous drainage, pancreatic endocrine deficiency, pancreatic exocrine deficiency, or the need for enzyme use. CONCLUSIONS: Endoscopic management of INP performs better compared to surgical treatment due to its lower complication rate and higher patient life quality.

[Spatiotemporal Distribution of Ammonia Emissions from Poultry Farming in the Yangtze River Delta Based on Online Monitoring Derived Local Emission Factors].

In order to obtain the ammonia emission level and space-time distribution characteristics of the poultry production industry in the Yangtze River Delta, an online high-resolution monitoring system was used to continuously monitor the atmospheric ammonia concentration in the breeding house and compost shed in a typical large-scale layer farm. By obtaining the ammonia emission level and emission factor during each growth stage, we established the localized ammonia emission inventory for the poultry production industry in the Yangtze River Delta. The results showed that the average daily ρ(NH3) in the breeding house and compost shed for spring, summer, autumn, and winter were (1.85±0.38), (4.58±0.33), (3.87±0.12), and (2.83±0.47) mg·m-3 and (2.04±0.50), (4.04±1.04), (2.51±0.67), and (1.55±0.16) mg·m-3 respectively. Ammonia emissions showed a significant daily hourly change trend. The highest hourly ammonia concentration in the layer house appeared from 13:00-14:00 in the afternoon, and the minimum appeared from 01:00-03:00 in the morning. The highest hourly ammonia concentration in the compost shed occurred between 16:00-19:00 in summer and autumn, whereas the diurnal changes in spring and winter were not significant. Hourly changes in ammonia emissions during the day were mainly affected by daily temperature, poultry activities, and manure management. Ammonia concentrations at different growth stages of laying hens showed significant differences. ρ (NH3) from young chickens, laying hens, and pre-eliminated chickens were (1.85±0.38), (2.83±0.47), and (1.61±0.32) mg·m-3, respectively. The ammonia emission rate from laying hens reached 1.53 times and 1.65 times that of young chickens and pre-eliminated chickens, respectively. Metabolism levels and feed intake at different growth stages were the main reasons for the differences in ammonia emissions. Ammonia emission factors for the layer house and compost shed in spring, summer, autumn, and winter were (0.13±0.02), (0.54±0.01), (0.39±0.01), and (0.17±0.01) g·(bird·d)-1 and (0.07±0.01), (0.17±0.02), (0.08±0.01), and (0.04±0.01) g·(bird·d)-1, respectively. Annual ammonia emission factors reached (0.11±0.06) kg·(bird·a)-1 and (0.03±0.02) kg·(bird·a)-1, respectively. Our results suggest that ambient temperature, ventilation mode, chicken house type, and manure removal frequency were the main influencing factors of ammonia emissions from poultry production. The uncertainty ranges of the ammonia emission coefficients reached±122%,±79%, and±74%, and±56%, respectively. Great uncertainties were generated when empirical emission factors were used for emission inventory establishment. Based on the results of online monitoring, model simulation, and literature analysis, we established an ammonia emission inventory for the poultry production industry within the Yangtze River Delta region by adopting the emission factors of (0.16±0.08) kg·(bird·a)-1. In 2019, the total ammonia emission from poultry production was (108.81±54.41) kt. In terms of spatial distribution, ammonia emission intensities in the northern regions were significantly higher than those in the southern parts. The ammonia emission intensities during summer were 3.38-3.56 times higher than those in spring and winter.

[Emission Characteristics, Transformation Mechanism, and Reduction Potential of Ammonia Emissions from a Crop Rotation System in Yangtze River Delta].

To study the characteristics and reduction potential of the ammonia emissions of a crop rotation system in the Yangtze River Delta, we monitored and compared the ammonia fluxes from two rotation systems:a conventional rice/winter wheat rotation system and a rice-shrimp cultivation/Chinese milk vetch rotation system. This study was conducted through closing chamber methods to investigate the influencing factors and transformation mechanism of ammonium emissions between the two studied cultivation patterns. Additionally, we established the temporal-spatial emission inventory by sorting out the local ammonia emission factors of farmland in the Yangtze River Delta in the last ten years. The emission reduction effects under different ammonia emission reduction paths were also obtained. The results showed that, the cumulative amount of ammonia emissions throughout the whole monitoring year for the conventional rice/winter wheat rotation system (CR-W) and the rice-shrimp cultivation/Chinese milk vetch rotation system (RS-C) were 65.95 and 20.31 kg·hm-2, respectively, whereas the ammonia loss rates of CR-W and RS-C were 10.86% and 9.20%, respectively. Field surface water NH4+-N, field surface water pH, and topsoil NH4+-N were the major internal factors of ammonia emissions from paddy fields, whereas topsoil NH4+-N and atmospheric temperature had an important impact on ammonia emissions in the wheat season. The ammonia flux/field NH4+-N ratio (ARN) of field surface water under the CR and RS modes in the rice season reached 0.35±0.27 and 0.14±0.19, respectively, which was 10-25 times that of topsoil in the wheat season, such that the ammonia emission flux in the rice season was significantly higher than that in the wheat season. Under the conditions of high field water pH (8.0-9.0), atmospheric temperature (>28℃), and wind speed (>5.0 m·s-1), the ammonia flux/field NH4+-N ratios (ARN) were around 1.6-4.6 times that under low pH, temperature, and wind speed conditions, indicating that those three factors were the main factors affecting the conversion of NH4+-N from farmland to atmospheric NH3. Fertilization types also had significant effects on ARN; under different conditions, the ARN of urea was 1.5-5.5 times that of organic fertilizer. In 2019, the ammonia emission flux of rice and wheat under a conventional planting pattern in the Yangtze River Delta were (49.2±17.6) kg·hm-2 and (16.0±13.5) kg·hm-2, respectively, whereas the ammonia loss rates of rice and wheat were (20.1±5.7)% and (5.9±3.6)%, respectively. The ammonia emission loss rate of the former was about three times that of the latter. The ammonia emission inventory built by local factors shows that the total ammonia emissions of the farmland rotation system in the Yangtze River Delta reached (400.3±206.4) kt in 2019, which was mainly concentrated in the central and northern regions of Anhui province and Jiangsu province, and the ammonia emission intensity reached (1.33±1.39) t·km-2. The selection of different emission factors had a relatively large impact on the change range of the inventory results, reaching the standard of -51.6%~51.6%. Through combing and analyzing the six main paths of ammonia emission reduction in farmland, it was found that nitrogen fertilizer synergism was the best way to reduce ammonia emissions, with the efficiency of (30.9±51.4)%; however, the grain yield increase rate was (-4.2±17.4)%, with great uncertainty. The ammonia emission reduction effect of adding soil additives was relatively poor (-5.4±45.1)%; however, the grain yield increase rate was the highest among those of the six emission reduction paths, reaching (6.8±23.9)%. The ammonia emission reduction effect and grain yield increase rate of the ecological planting and breeding mode were (22.3±15.1)% and (5.6±3.8)%, respectively, which had the advantages of reducing ammonia emissions and increasing crop yield.