Removal of H2S by co-immobilized bacteria and fungi biocatalysts in a bio-trickling filter

Biological control of odor gases has gained more attention in recent years. In this study, removal performance of a vertical bio-trickling filter inoculated with bacteria and fungi was studied. Bacteria and fungi were isolated from activated sludge in a sewage treatment plant. By adopting “three step immobilization method”, the bio-trickling filter could degrade pollutant immediately once hydrogen sulfide (H₂S) passed. The optimal empty bed resident time was 20 s. The optimal elimination capacity was about 60 g H₂S m^?3 h^?1 with removal efficiency of 95%. And the maximum elimination capacity was 170 g H₂S m^?3 h^?1. Pressure drop was ranged between 5 and 15 mm H₂O per bed over the whole operation. Removal efficiency was not affected obviously after terminating nutrient supply. The bio-trickling filter could recover back after shut down H₂S gaseous and liquid supplies simultaneously. Microbial community structure in the bio-trickling filter was not changed significantly.Combining bacteria and fungi would be a better choice for inoculation into a bio-trickling filter because of the quickly degradation of H₂S and rapid recovery under shut-down experiment. This is the first study attempting to combine bacteria and fungi for removal of H₂S in a bio-trickling filter.     

CuCo2S4/sulfite reaction for efficient removal of tetracycline in water

Water pollution by antibiotics is an increasing concern, which may be addressed by advanced oxidation processes using sulfites as precursors of sulfate radicals (SO₄^·–), yet the efficiency of sulfite activation is limited. Here, we tested copper cobalt sulfide (CuCo₂S₄) to activate sulfite, based on the synergy among transition metals and the facilitation of transition metal redox circulation by reductive sulfur species. We analyzed CuCo₂S₄ structure by X-Ray photoelectron spectroscopy, and we studied the effect of pH and radical scavengers. Results show 90–100% abatement of tetracycline concentration at pH 8.0–10.0, with SO₄^·– and HO^· as the main reactive radicals. This finding is explained by the accelerated redox recycling of copper and cobalt by sulfur, and by the synergetic effect between active cobalt and copper sites.

     

中国环境监管的需求分析及对策建议

科学高效的环境监管体系的构建是防范突发环境风险的前提和关键,本文对突发性环境事件进行需求分析,提出构建完善的环境监管体系的可行性建议。从法律法规的支撑,各级协调与指挥机构的建立,应急救援资源的储备,监控预警网络的优化以及监管模式的完善的角度,建立完善的监管体系,把各个环节有机联系,实现事态有效控制,减少事故损失,确保人民生命、财产安全和灾后恢复。     

事故隐患目标管理中四版图的应用

在安全生产管理中,对生产过程中可能存在的隐患、有害与危险因素、缺陷等进行检查,以确定其存在的状态,以及它们转化为事故的条件,从而制定整改措施,消除隐患. 1隐患发现率阐述 隐患发现率HR=事前隐患发现并发放整改通知的个数÷(事前隐患发现个数 产生影响的隐患个数)×100%