天然秸秆纤维素分解菌的分离选育

从土壤、酒糟、腐烂的玉米秸秆及牛粪中共分离到14株能分解纤维素的真菌菌株,外加已保藏的10株共24株菌株。分别对其进行了滤纸分解度、羧甲基纤维素(CMC)酶活和天然纤维素酶活的测定。筛选出6株对天然纤维素有较强的降解能力,酶活力在60mg/mL.d以上的菌株。通过改变其培养基中天然纤维素的含量,发现随着培养基中天然纤维素含量的减少,酶活力也随之降低。     

Miscanthus × Giganteus straw and pellets as sustainable fuels

In this paper we present, for the first time, data on the combustion of Miscanthus × Giganteus straw and pellets. We found that the heating value of Miscanthus is 17.744 MJ/kg. The gaseous emission indices of SO₂, NO _x and total organic carbon (TOC) in the exhaust are reported and compared with the European standards for biomass boilers. On the basis of our results, it is possible to evaluate a net energy yield between 152 and 326 MJ/hectare/year for the cultivation of Miscanthus with an energy balance estimated to be in the range of 7.7–15.4. According to the presented results, it seems reasonable to consider Miscanthus as a promising candidate as alternative fuel.     

稻草制取糠醛联产高效复合肥工艺研究

研究了以稻草为原料，用改良硫酸法制取糠醛联产复合肥的工艺条件。结果表明，用20%硫酸（液固质量比为2.5:1），加入复合添加剂（1）（主要成分为磷酸钙、磷酸、重钙、亚硫酸氢钠等）或（Ⅱ）（主要成分为磷酸、重钙等）添加比例为15%～30%(占原料质量分数）、常压、100℃蒸馏2h，出醛率达理论出醛率的70%～80%，废渣全部变为中性复合肥料。     

Atmospheric pollution of agriculture-oriented cities in Northeast China: A case in Suihua

Agriculture-oriented cities in Northeastern China have experienced frequent atmospheric pollution events. Deeper understandings of the pollution characteristics, haze causes and effects of management on local air quality are crucial for conducting integrated management approaches for the sustainable development of agriculture-oriented cities. Taking a typical agriculture-dominant city (i.e., Suihua) in Northeast China, we analyzed in detail the characteristics and causes of atmospheric pollution and evaluated the straw-burning prohibition using multisource data. The results showed a clear temporal pattern of air quality index (AQI) on an annual scale (i.e., 2015-April 2019), with two typical pollution periods occurring in late autumn and early spring. The large areas of concentrated straw burning at local and regional scales accounted for the first period (i.e., October and November), while dust emissions and farming disturbances comprised the second period. The interannual variation in pollution periods among these years was large, showing similar trends from 2015 to 2017 and the postponed late-autumn pollution period in 2018. Our evaluation has shown that the prohibition effect of straw burning significantly improved air quality in 2018, with a reduction of 59% ± 88% in the PM_2.5 concentrations in October and November compared to 2015–2017. However, From October to April of the following year, the improvement effect was not significant due to postponement of straw burning to February or March. Our analysis also highlighted the roles of meteorological conditions, Therefore, combined with the promotion of straw utilization, scientifically prescribed burning considering the burning amount and location, meteorological conditions and regional transportation should be implemented.     

Waterfowl foraging in winter-flooded ricefields: Any agronomic benefits for farmers?

Winter-flooding of ricefields provides foraging habitat to waterfowl, which in return may bring agronomic benefits to farmers. Our study experimentally tested the effect of mallards (Anas platyrhynchos) on the standing stalks and weed seed bank in the Camargue (France), both of which present major challenges for farmers. Three duck densities were tested: (D1) 5 ducks ha⁻¹ (historical nocturnal density), (D2) 23 ducks ha⁻¹ (present nocturnal density), and (D3) 300 ducks ha⁻¹ (Asian rice-duck farming density). The ducks reduced the stalks significantly: −27 % (D1), −52 % (D2), and −91 % (D3). Conversely, they decreased the number of seeds by only 3 % (D3) and the seed mass by about 21 % (D1 and D3), which was not significant. Besides they had no effect on seed species richness. This study clearly demonstrates that the winter-flooding effect on straw decomposition can be enhanced by waterfowl foraging, hence showing an agronomic benefit from ducks to farmers. However, there was no clear effect in terms of seed bank reduction.     

Pyrethroid use-malaria control and individual applications by households for other pests and home garden use

Presence of pyrethroid insecticides in human breast milk and in thatch wall material of dwellings from Southern Africa subtropical area (Manhiça, Mozambique) was investigated to assess potential pyrethroid route of human exposure. Human breast milk samples were collected during 2002 when pyrethroids were widely used as insecticides for mosquito bed nets in Mozambique for malaria control. The median concentration value of total pyrethroids ranged between 87 and 1200 ng/g lw, with λ-cyhalothrin being the most predominant pyrethroid in human breast milk contributing for 35% of the total amount. Moreover, and for the first time, an isomer-specific enrichment was found in human breast milk, showing a selective isomeric accumulation or metabolism in the human body. Based on the calculated pyrethroid concentrations in human breast milk, the daily ingestion rate of pyrethroid was estimated. The nursing infant dietary intake ranged from 0.67 to 9.0 μg (kg of body weight)^− 1 day^− 1. In addition, thatch materials collected after the reintegration of dichlorodiphenyltrichloroethene (DDT) as insecticide residual spraying (IRS) in Mozambique, showed the presence of pyrethroids with concentration values ranging between 6.9 and 700 ng/g dw. In thatch material as well as in human breast milk, pyrethroid contamination was mainly attributed to the agriculture usage of this insecticide knowing that agriculture represent the 80% of the economy in Mozambique. However, a possible usage of this insecticide as IRS in Mozambique cannot be excluded despite their low efficiency for malaria control. The continued use of these compounds (both for agriculture and malaria prevention) and the ingestion rates calculated from the breast milk concentrations indicate that these insecticides cannot be overlooked for the assessment of the lactation risks of breastfeeding infants from the Manhiça region.     

Comparisons of two serious air pollution episodes in winter and summer in Beijing

Characteristics of two serious air pollution episodes(9–15 January, as the winter case; and30 June to 1 July, as the summer case), which occurred in Beijing in 2013 were investigated and compared using multi-method observations and numerical simulations. During these two air pollution episodes, PM_(2.5) concentrations varied significantly within Beijing, with PM_(2.5) concentrations in southern parts of Beijing being significantly higher than in northern areas. Typically, heavy air pollution episodes begin in the southern parts and disperse towards the northern parts of Beijing. Clearly, synoptic patterns and the stability of atmospheric circulation patterns were the main factors controlling air pollution in Beijing.During the winter case, a warm center above 900 h Pa occurred over Beijing. Meanwhile, in the summer case, although there was only a weak inversion, the convective inhibition energy was strong(over 200 J/k G). This clearly influenced the duration of the air pollution event. Except for the local accumulation and secondary atmospheric reactions in both cases, regional straw burnings contributed a lot to the PM_(2.5) concentrations in summer case.Using the CAMxmodel, we established that regional transport contributed almost 59% to the PM_(2.5) averaged concentration in Beijing in the winter case, but only 31% in the summer case. Thus, the winter case was a typical regional air pollution episode, while the summer case resulted from local accumulation straw burnings transportation and strong secondary atmospheric reactions. Given that air pollution is a regional problem in China, consistent and simultaneous implementation of regional prevention and control strategies is necessary to improve regional air quality.     

城市污水处理厂剩余污泥堆肥的实验研究

污泥由于产量大且成分比较复杂,如何对它进行无害化,稳定化处理,使其成为替代资源已经越来越受到人们的关注。基于好氧堆肥装置系统,以徐州市某污水处理厂的剩余污泥为研究对象,研究了污泥处理过程中温度、含水率、有机质、有机碳以及pH值和重金属等指标的变化规律。研究结果表明：采用污泥与稻草的体积比为1：2的比例堆肥,控制初始含水率为70％左右,可顺利实现升温。堆肥15d后,物料含水率、有机质、有机碳都有了明显的降低;总氮、总磷以及水溶性钾的含量都有了不同程度的增加;重金属含量有了一定程度的降低,符合堆肥的要求。     

农村秸秆最优利用方法初探

本文介绍了秸秆的八种利用途径，并从社会，环保，能源技术经济学角度出发，对各种利用途径所涉及的技术、经济、社会等各方面因素进行综合分析评价，从而为各地区因地制宜地优选秸秆综合技术方案，达到秸秆最优利用提供参考。     

秸秆成型燃料棒替代普通燃煤在0.8 t/h锅炉应用性试验

采用新研制开发的秸秆成型燃料棒与普通燃煤在基本相同的条件下进行对比试验，结果表明在0.8t／h工业锅炉上燃用相等量秸秆成型燃料棒与普通燃煤时锅炉的出力相当，而烟气污染物排放浓度远低于国家排放标准的限值。