微波-活性炭法处理氨氮废水的研究

[目的]探讨微波-活性炭法处理氨氮废水的可行性及最佳试验条件。[方法]以模拟氨氮废水为处理对象,研究了活性炭存在条件下,溶液pH、空气通入状况、活性炭投加量、微波作用功率和时间对微波辐射下氨氮废水去除效果的影响。[结果]微波-活性炭法对氨氮具有较好的去除作用,向溶液中通入空气,也能在一定程度上提高氨氮的去除率;提高溶液pH,增大微波作用功率、延长微波处理时间均能提高氨氮的去除率,而活性炭用量对氨氮去除效果的影响不显著;微波-活性炭联合技术法用来处理氨氮废水有很好的可行性,正交试验结果表明,活性炭投加量为0.5 g,pH=11,微波功率为850 W,处理时间4 min时,氨氮去除率可达92.47%。[结论]该研究为氨氮废水的处理提供了一种新的方法,即微波-活性炭法。     

高氨氮降解菌株DA-1的分离鉴定及降解性能研究

一株高效的氨氮降解菌株DA-1从沼液中分离,16S rDNA序列分析将其鉴定为Arthrobacter arilaitensis。实验研究了不同碳源、C/N比及氨氮浓度对菌株DA-1氨氮降解性能的影响。结果表明:多种有机碳源条件下,当C/N比为10、菌液接种量为1%(v/v)时,在2 d内,菌株DA-1的氨氮降解率达到了80%以上(100 mg/L),随着氨氮浓度的上升降解率随之下降,当氨氮浓度高达1000 mg/L,降解率下降至26.3%。实验还考察了菌株DA-1对沼液样品的氨氮降解能力,通过添加乙醇调节沼液的C/N比,处理5 d后,沼液样品的氨氮浓度下降了70%以上。     

几类干草防腐剂简介

对牧草进行打捆储藏可以有效降低牧草营养损失,但储藏过程中因微生物的作用会导致牧草发热甚至腐败从而降低其饲用价值。因此,在干草调制过程中,应添加干草防腐剂以抑制微生物的生长和繁殖。本文对几种常用干草防腐剂进行介绍,以供同行调制干草时参考。     

Characterization of Influence of Manure Handling System and Feeding on the Level of Ammonia Release Using a Simple Method in Cow Houses

The effects of manure handling system and feeding of dairy cows were studied using a simple method to analyse the level of ammonia release in cow stables. Two ratios based on the balances of ammonia and sensible heat, and ammonia and carbon dioxide, respectively, in animal houses were determined and considered to give characteristic levels of the release of ammonia in relation to the animal density independently of the ventilation rate. This required measurements of ammonia, carbon dioxide and temperature with hand-held instruments in the buildings and in outside air. In total, 34 dairy herds were investigated in the south of Sweden. The results clearly demonstrated higher release of ammonia from free stall barn with liquid manure than from conventional tie stall barn with solid manure. There was a clear effect of the content of crude protein, gram per kg dry matter, in the total feed ration on ammonia release in tie stall barn with liquid manure.     

红壤不同含水量对尿素氨挥发的影响

根据第四纪红壤水分特征设计160、200、240、280、320、360g/kg6个土壤含水量处理,通过温室模拟,研究了红壤不同含水量对尿素氨挥发的影响。结果表明,等量尿素施入红壤后,氨挥发通量与土壤含水量之间无显著相关性,而高含水量(280、320、360g/kg)处理氨挥发通量峰值较低含水量(160、200g/kg)处理提前10天。氨挥发过程可分为快速-慢速2个阶段,氨累积挥发量(y)与对应时间(t)符合Elovish动力学方程(y=a blnt)。第1～10天,氨挥发累积量随红壤含水量的增加而递增;第11天后,以含水量为240g/kg处理的氨挥发累积N量最低。试验期间,氨挥发累积总N量,以含水量240g/kg时最低(0.90gN),含水量320g/kg时最高(1.16gN),分别占尿素施入N量的9.0%和11.6%。     

Potential for mitigating atmospheric ammonia in Canada

Most ammonia (NH₃) emissions (85%) in Canada come from agricultural sources (400 kt/yr). There are international conventions that require countries to mitigate NH₃ emissions but there are no federal or provincial guidelines in Canada stipulating emission targets or best practices for agriculture. This study examines the potential for mitigating atmospheric NH₃ using a range of approaches. Taking current farm practices into account, employing proven low‐cost measures (low‐emission slurry application and slurry storage covers) would reduce annual emissions from livestock operations by 16 kt NH₃‐N, while using all available low‐cost measures would reduce emissions by 79 kt NH₃‐N or 26% of livestock emissions. Another 36 kt/yr could be avoided by improving fertilizer practices, so that the total potential reduction would be about 29% of all agricultural emissions. Emissions from beef cattle and pig production could be reduced by 18% if consumption was cut by 50%, with greater mitigation if production for export was reduced, although the economic and social consequences need to be considered. Mitigation practices must be viewed in the context of possible pollution swapping especially in surplus nitrogen situations. Emissions must also be considered in terms of atmospheric NH₃ transport to and from the USA, therefore bi‐national agreements to jointly reduce emissions might be needed. It may be more cost‐effective in Canada to strategically reduce emissions to minimize risks to health (from particulate matter) and the environment rather than to reduce annual national emission targets.     

氨氮与亚硝酸盐对吉富罗非鱼肠道菌群的影响

氨氮和亚硝酸盐是蛋白质的代谢副产物,水体中高浓度的氨氮和亚硝酸盐会显著抑制罗非鱼的免疫力。肠道微生物与鱼类的免疫息息相关,然而氨氮和亚硝酸盐是否影响罗非鱼的肠道微生物仍不清楚。本研究采用基于16S rDNA基因序列的高通量测序,研究了氨氮和亚硝酸盐对吉富罗非鱼肠道菌群的影响。结果表明,罗非鱼肠道微生物群落主要以变形菌门和放线菌门为主。氨氮和亚硝酸盐不改变罗非鱼肠道菌群的alpha多样性,但显著改变物种组成,其中Aurantimicrobium菌属在两种处理下比例显著降低。原核类群功能注释(FAPROTAX)分析表明,氨氮和亚硝酸盐胁迫导致的差异ASVs主要涉及化能异养、好氧化能异养、硝酸盐还原、脂肪族非甲烷烃降解、芳香烃降解和芳香族化合物降解。本研究通过了解氨氮和亚硝酸盐对罗非鱼肠道微生物的影响,为研究肠道微生物对罗非鱼免疫的影响奠定基础。     

河水氨污染急性死鱼模拟试验

为了查明河水中氨污染对常见淡水鱼类危害程度,设计本项模拟试验。经测定：水中氨氮含量＞ ４ ｍ ｇ／Ｌ时,淡水鱼就会出现急性中毒现象。不同种类、大小的淡水鱼对氨氮的忍耐度不同,呈一定规律。中毒症状主要表现为鳃部呼吸、血液循环障碍及体表应激反应     

高盐胁迫对黄边糙鸟蛤(Trachycardium flavum)呼吸排泄和免疫酶活性的影响

为了探讨急性高盐胁迫对黄边糙鸟蛤(Trachycardium flavum)生理代谢和免疫酶活性的影响,分析了盐度自31骤升至37后2、12、24、48和72 h黄边糙乌蛤耗氧率、排氨率和不同组织Na+/K+-ATP酶、超氧化物歧化酶(SOD)、酸性磷酸酶(ACP)和碱性磷酸酶(ALP)的活性.结果显示,处理后2h耗氧率先降低,然后逐渐升高,在24和72 h显著高于对照组(P＜0.05);排氨率在2h极显著降低(P＜0.01),且在各时间点均低于对照组.外套膜、肝胰腺中Na+/K+-ATP酶活力在12 h显著降低(P＜0.05),肌肉和鳃中活力与对照组无显著差异.外套膜、肝胰腺和鳃中SOD活力在24 h达到最高值,显著高于对照组(P＜0.05),其后逐渐降低;肌肉中SOD活力在48 h达到最高值后降低.外套膜和鳃中ACP活力先升高后降低,肝胰腺中ACP活力显著降低(P＜0.05)后逐渐升高,肌肉中ACP活力与对照组无显著差异.肝胰腺和鳃中ALP活力先降低后显著升高(P＜0.05),与对照组相比,外套膜和肌肉中ALP活力无显著差异.结果表明,急性高盐胁迫对黄边糙鸟蛤的代谢水平和免疫酶活性均有显著影响且表现出时间效应性,高盐胁迫对免疫酶活性的影响具有组织特异性.     

中国对虾(Fenneropenaeus chinensis)“黄海3号”新品种的培育

2006年收集中国对虾“黄海1号”保种群以及海州湾、莱州湾2个野生群体为基础群体构建核心育种群,采用群体选育技术以仔虾Ⅰ期耐氨氮胁迫成活率和收获时对虾体重为选育指标,经过连续5代选育,培育出中国对虾“黄海3号”新品种。新品种耐氨氮胁迫能力强,仔虾Ⅰ期成活率较商品苗种提高21.2%,养殖成活率提高15.2%;生长速度快,收获对虾平均体重较商品苗种提高11.8%。AFLP技术分析获得5代选育群体的平均多态位点比例分别为42.28%、40.64%、40.32%、39.95%和38.05%。研究结果显示,随着选育世代的增加,选育群体的遗传多样性呈现下降趋势,但随着选育时间的延长,世代之间的分化逐渐降低,群体的遗传结构开始趋于稳定。