香肠整体营养价值评价与包装正面标签应用研究进展

为促进我国消费者对香肠的合理消费与饮食健康，引导企业生产营养健康的香肠，利用《中国食物成分表》（第1册第2版）的16 种香肠及其营养素数据，构建富含营养素食物（nutrient-rich foods，NRF9.3）模型，评价香肠整体营养价值，并借鉴瑞典的锁孔（Keyhole）标识和英国的多交通灯信号标签进行相应的包装正面（front of package，FOP）标签应用探索。结果表明：除了儿童肠、火腿肠外，14 种香肠的NRF9.3＜0，每100 kcal的推荐性营养素含量均低于限制性营养素，对人体的营养价值较低，适合采用总结指示体系和特定营养素体系的FOP标签进行标示；因此，居民日常应限制香肠摄入，建议对脂肪、盐含量超标的香肠采用红色交通灯信号标签提醒消费者，对NRF9.3＞0的香肠实施单一的健康选择标识推荐消费者选购。     

于都黄麟-祁禄山地区土地质量地球化学评价

通过对于都县黄麟-祁禄山地区开展1:5万土地质量地球化学调查,在野外土壤样品采集和化验测试的基础上,系统地研究了影响土地质量的各项地球化学指标特征与控制因素,基本查明有益元素、重金属元素分布,划分出重点污染区和绿色土地发展区,并进行土地质量等级评价,为永久基本农田建设、土地资源开发与利用等方面提出建议。     

Carbon,nitrogen and phosphorus recovery from liquid swine wastes: a review

Due to the pollution characteristics of the wastewater generated in piggeries, these waste streams have to be treated before discharging into the environment. These wastes have a high content of organic matter, nitrogen and phosphorus that can be converted or recovered into valuable products. The valuation of swine waste by anaerobic digestion has already been assessed, but no systematic review on the technologies used for recovering nutrients from this waste has been reported to date. Therefore, the present work has the goal of presenting the most studied technologies to different scales of recovery of carbon (i.e. organic matter), nitrogen and phosphorus from swine waste. The main characteristics and parameters of the processes involved in these technologies (mainly air stripping, membrane, enhance biological phosphorus removal and struvite formation) are also highlighted, pointing out its advantages and disadvantages and posing some final feasibility considerations on the subject addressed. Experiments reported in the literature proved that technologies used for nutrient recovery from swine waste are mostly applied to the effluents previously treated by anaerobic digestion as a primary treatment, and greater effort is required for the future implementation of these technologies in large scale. © 2020 Society of Chemical Industry     

Mechanical sludge disintegration for the production of carbon source for biological nutrient removal

The primary driver for a successful biological nutrient removal is the availability of suitable carbon source, mainly in the form of volatile fatty acids (VFA). Several methods have been examined to increase the amount of VFAs in wastewater. This study investigates the mechanism of mechanical disintegration of thickened surplus activated sludge by a deflaker technology for the production of organic matter. This equipment was able to increase the soluble carbon in terms of VFA and soluble chemical oxygen demand (SCOD) with the maximum concentration to be around 850 and 6530 mgl(-1), for VFA and SCOD, respectively. The particle size was reduced from 65.5 to 9.3 microm after 15 min of disintegration with the simultaneous release of proteins (1550 mgl(-1)) and carbohydrates (307 mgl(-1)) indicating floc disruption and breakage. High performance size exclusion chromatography investigated the disintegrated sludge and confirmed that the deflaker was able to destroy the flocs releasing polymeric substances that are typically found outside of cells. When long disintegration times were applied (>or=10 min or >or=9000 kJkg(-1)TS of specific energy) smaller molecular size materials were released to the liquid phase, which are considered to be found inside the cells indicating cell lysis.     

Nitrogen inputs to stream water from forests along an elevational gradient in New Mexico

Studies of nitrogen inputs in precipitation and outputs in stream water for a number of terrestrial ecosystems support the hypothesis that undisturbed communities have the ability to reduce losses of nitrogen via stream water. In spite of different levels of biomass, productivity and stream discharge for these communities, net losses of nitrogen were similar. Maintaining nitrogen in an organic or cation form (NH₃, NH₄⁺) is an important factor in minimizing loss. This may be accomplished by slow rates of mineralization, rapid plant uptake, and denitrification through the electron sink pathway. Denitrification by the dissimilatory pathway may also be important.     

城市污水处理厂增加脱氮除磷功能的改造实践

为了满足国家对城市污水厂出水氮磷的排放要求,采用倒置AAO工艺对常州市某污水处理厂的三期工程原有普通活性污泥法工艺进行了改造.在没有新建生化反应池和增加回流系统的前提下,通过提高活性污泥浓度,在原生化反应池内进行了缺氧/厌氧/好氧功能区的分配,取得了良好的脱氮除磷效果.新工艺对NH3-N和TP的去除率均达到90%以上,对TN的去除率为45.4%.通过对生化反应池内污染物浓度沿程变化情况的监测,初步分析了工艺运行机理,为今后其它城市污水厂的改造积累了经验.     

Phytoplankton in a polluted subarctic lake before and after nutrient reduction

Phytoplankton and water chemistry were studied in a eutrophic subarctic Swedish lake before and after nutrient reduction. Pollution started in 1964 and the lake had received about 4.5 tons of phosphorus by the time the treatment plant was built in 1974. After that only 18–20 kg P yr^?1 entered the lake. Before nutrient reduction the phytoplankton consisted principally of three species, Dictyosphaerium pulchellum var. minutum, Chromulina cv. darlecarlica and Cryptomonas cv. ovata. Two years after the P-load was reduced Chlamydomonas spp and Mallomonas akrokomos predominated in the plankton and their dominance has been maintained during the period of study. Seasonal average phytoplankton biomass decreased from 11.2 g m^?3 in 1973 to 2.9 g m^?3 in 1980. Average seasonal total phosphorus concentrations decreased from 168 μgl^?1 in 1973 to 74 μgl^?1 in 1980. Average Secchi depth readings increased from 1.3 m in 1973 to 2.1 m in 1980. Blue-green algae never had any quantitative importance in the lake and no blooms were observed.