Treatment of Enzymolysis Wastewater by Centrifugation- Coagulation- Fenton Reagent Oxidation- Adsorption Process

[ Objective ] The study aimed to discuss the optimal conditions for the treatment of enzymolysis wastewater by centrifugation - coagu- lation - Fenton reagent oxidation - adsorption process. [ Metbod] According to the water-quality characteristics of wastewater from a heparin so- dium production factory of Jiangsu Province, enzymolysis wastewater was segregated from intestinal lavage wastewater and treated through cen- trifugation- coagulation- Fenton reagent oxidation-adsorption process, and the optimal technical parameters were determined. E Resultl After enzymolysis wastewater was centrifuged at a speed of 4 000 rpm, 0.6 g/L CTS as the coagulant was added to the supematant. Hereafter, pH of the coagulated effluent was adjusted to 3, and then 1.5% （V/V） H2O2 was added to the coagulated effluent; a certain amount of ferrous sul- fate （n H2O2-.n FeSO4 . 7H2O =8：1 ） was added to the mixture; the reaction conducted for 30 min, and then solution pH was adjusted to about 9. Finally, the oxidized effluent flowed through a resin red until the adsorptive capacity reached 240 BV, and COD of the effluent water was lower than 100 mg/L, meeting the Grade-I standard of Comprehensive Discharge Standard of Sewage （GB8978-1996）. [Condusio] The research could provide a new process for the treatment of enzymolysis wastewater.

Treatment of Intestinal Lavage Wastewater by Coagulation-ASBR-SBR Process

[ Objective] The study aimed to discuss the optimal conditions for the treatment of intestinal lavage wastewater by coagulation-ASBR- SBR process. [ Method] According to the water-quality characteristics of wastewater from a heparin sodium production factory of Jiangsu Province, intestinal lavage wastewater was segregated from enzymolysis wastewater and treated using coagulation-ASBR-SBR process, and the effects of PFS dosage, HRT of ASBR and SBR reactor on the removal rate of COD and NH4＊ -N were analyzed. [ Result] The best dosage of PFS was 0.15 g/L, and the optimal HRT of ASBR reactor was 36 h, while the best HRT of SBR reactor was 15 h. Under the optimal conditions above, the removal rate of COD and NH,＊ -N reached 99.1% and 97.3% respectively, and the quality of the effluent water could reach the first standard of Comprehensive Discharge Standard of Sewage （GB8978-1996）. [ Conclusion ] The research could provide a new process for the treatment of intestinal lavage westewater.

Cloning, Sequence Analysis, and Prokaryotic Expression of the Porcine DECR1 Gene

2,4-dienoyl-CoA reductase 1 （ DECR1 ） is the key rate-limiting enzyme in the metabolism of polyunsaturated fatty acids. Although this protein has been studied in a variety of mammals, its role in por- cine is yet to be fully elucidated. However, it is a candidate determinant/indicator of meat quality, growth traits, and carcass quality. Here, we employed RT-PCR and rapid amplification of cDNA ends （RACE） analysis to amplify the full-length cDNA of DECR1 from Mashen pig liver, and cloned it into the expression vector pET-32a＋. After confirmation by sequencing and restriction analysis, the recombinant plasmid was transformed into E. coli BL21 cells. The cDNA of pig DECR1 contained 2,352 nucleotides, including a 987 bp open reading frame flanked by a 53 bp 5＇-untranslated region （UTR） and a 1,312 bp 3＇-UTR. The pig DECR1 coding sequence encoded 328 amino acid residues, which shared 99%, 88%, 87%, 87%, 87%, 87%, and 83% identity with those of Sus scrofa （predicted）, Bos taurus, Homo sapiens, Macaca mulatta, Pan troglodytes, Equus caballus, Canis, and Mus musculus, respectively. SDS-PAGE analysis revealed that the recombinant protein was expressed and that the expression level reached its highest level after 4 h induction. Western blot analysis indicated that the molecular weight of the expressed protein was the same as that predicted, ap- proximately 35 kDa. Collectively these data provide the basis for further studies into the physiological functions and molecular mechanisms of the pig DE- CR1 gene.

高等级生物安全实验室采用循环风问题探讨

通风空调系统是保障高等级生物安全实验室稳定运行的重要措施,为了避免交叉污染,一般采用全新风空调系统.为了降低能耗和运行费用,很多高等级生物安全实验室采用了变风量运行、热回收装置等节能技术措施,取得了一定的节能效果,但不是很显著.为了进一步实现高等级生物安全实验室的节能运行以降低运行成本,通风空调系统可否采用循环风问题成为实验室设计人员、运行维护人员、使用人员共同关心的话题.近年来,随着一些对室内环境参数有较高恒温要求的高精密仪器设备的应用,循环风问题更加凸显.本文对高等级生物安全实验室采用循环风问题进行了探讨,分析了国内外生物安全实验室相关标准要求、全新风系统的特点与挑战、循环风系统的风险与应对措施、循环风系统生物安全风险管理等,提出高等级生物安全实验室应优先采用全新风系统,当室内工艺设备对周围环境温度有较高要求或者考虑节能运行时,可考虑采用循环风系统,但应对回风进行有效的空气净化处理,同时应加强对循环风系统的生物安全风险管理.

我国4.4.2类高等级病原微生物实验室运行现状及问题思考

本文分析了我国数十家已建成并投入使用的4.4.2类高等级病原微生物实验室设施运行现状,包括实验室总体建设概况、实验室核心工作间环境参数、气流组织形式和压力调节方式,以及实验室自控系统运行可靠性等.研究结果表明,我国4.4.2类实验室大多设计为2~4间核心工作间、1套独立空调通风系统的形式.核心工作间采用上送上排和上送下排气流组织的比例大致相同,大多采用定送风变排风的压力调节形式.在室内环境和系统可靠性方面,研究发现实验室存在换气次数普遍偏高、部分实验室对室外大气绝对压力过大现象.此外,个别实验室存在因送/排风机切换或空调系统开/关机产生过大负压导致围护结构开裂、防护区最外围房间发生绝对压力逆转、UPS设置等问题.本文还分析了常见的共性问题产生原因,并给出了改进建议,以期提升我国高等级病原微生物实验室建设和运行管理水平、确保实验室设施环境满足建成后的实际需求、保障运行管理安全高效.

高等级生物安全设施通风系统风机配置模式综合分析

高等级生物安全设施是国家生物安全体系的基础支撑平台,是人口健康与动物卫生领域开展科研、生产和服务的重要保障条件,在我国重大疫病防控中发挥着至关重要的作用.生物安全设施安全的核心措施是通过通风空调系统保持负压,送、排风机是通风空调系统的重要设备,也是实现持续负压环境的核心保障.国内外相关标准规范、指南文件对高等级生物安全设施通风空调系统风机配置提出了明确要求.本文在对比分析这些要求的基础上,结合工程实例梳理了近年来我国高等级生物安全设施建设现状,对高等级生物安全设施通风空调系统风机运行模式、多台风机互为备用、送排风机变频控制、高海拔地区风机选型等关键问题进行了探讨.通过综合分析指出,高等级生物安全设施风机配置模式应经风险评估确定;通风空调系统设置相互独立、互为备用的两台风机是最佳工程选择;风机变频控制是高等级生物安全设施有效的压力梯度控制及节能运行措施之一;高海拔地区高等级生物安全设施应根据环境大气压对风机全压进行修正.

The influence of air supply inlet location on the spatial-temporal distribution of bioaerosol in isolation ward under three mixed ventilation modes

The outbreak of COVID-19 and the spread of infectious pathogens through bioaerosols have once again aroused widespread concern worldwide.Isolation ward is an important place to prevent the spread of infectious bioaerosols.However,infection of health care workers(HCWs)in the isolation ward often occurs,so it is ur-gent to carry out relevant research to reduce the cross-infection between HCWs and patients.In this paper,the temporal and spatial distribution characteristics of bioaerosols under three mixed ventilation modes in a single ward were studied,namely,upper supply side return air of Case 1 and side supply and side return ventilation are Case 2 and Case 3 respectively.The results show that the removal efficiency of bioaerosol in the ventilation mode of Case 3,in which directional airflow is formed from the air supply inlet to the release source and then to the exhaust outlet,is 46.6%and 67.7%higher than that of Case 1 and Case 2,respectively.In addition,ventilation methods based on mixed theory do not guarantee good air quality in the breathing zone(1.3 m to 1.7 m)of HCWs,which may increase the inhalation risk for HCWs.It is hoped that our results can provide some useful suggestions for optimizing the airflow layout of the isolation ward,reducing the risk of cross-infection,and virus elimination.

Comparative analysis of technical requirements for Heating,Ventilating,and Air Conditioning(HVAC)systems in high-biocontainment facility standards

In this study,standards of high-biocontainment facilities(including laboratories and large-scale production facilities)formulated by China and other countries were analyzed and compared,and the technical points and requirements for Heating,Ventilating,and Air Conditioning(HVAC)systems in different series of standards were discussed.The main focus was on expounding the design and verification of the containment area’s indoor parameters,ventilation system,filter design,integrity test,fan standby,airflow pattern,and system reliability.This study expects suggestions and opinions on the construction and development of biosafety facilities in China and the possible future revision of relevant national standards.

Prevention of surgical site infection under different ventilation systems in operating room environment

Biological particles in the operating room(OR)air environment can cause surgical site infections(SSIs).Various ventilation systems have been employed in ORs to ensure an ultraclean environment.However,the effect of different ventilation systems on the control of bacteria-carrying particles(BCPs)released from the surgical staff during surgery is unclear.In this study,the performance of four different ventilation systems(vertical laminar airflow ventilation(VLAF),horizontal laminar airflow ventilation(HLAP),differential vertical airflow ventilation(DVAF),and temperature-controlled airflow ventilation(TAF))used in an OR was evaluated and compared based on the spatial BCP concentration.The airflow field in the OR was solved by the Renormalization Group(RNG)k-e turbulence model,and the BCP phase was calculated by Lagrangian particle tracking(LPT)and the discrete random walk(DRW)model.It was found that the TAF system was the most effective ventilation system among the four ventilation systems for ensuring air cleanliness in the operating area.This study also indicated that air cleanliness in the operating area depended not only on the airflow rate of the ventilation system but also on the airflow distribution,which was greatly affected by obstacles such as surgical lamps and surgical staff.

Dust accumulated fungi in air-conditioning system:Findings based on field and laboratory experiments

This study analyzes the growth and reproduction of dust accumulated fungi(DAF)in an air-conditioning system based on field measurement and molecular biology,laboratory experiment and prediction modelling.The field measurement was conducted to collect dust in filter screen,surface cooler and air supply duct of two air handling units(AHUs).The results indicate that dust volume and fungal number in two AHUs generally met the hygienic specification of public buildings,but the cleansing did not fulfil requirements.High-throughput sequencing was conducted,revealing that the dominant fungal species were Alternaria_betae-kenyensis,Cladosporium_delicatulum,Aspergillus_sydowii,Verticillium_dahliae.Laboratory experiment was conducted to analyze the impact of several factors(e.g.growth time,temperature,relative humidity,duct material)and their combination on the DAF growth.The results indicate that fungal growth increased with time,peaking at 4 days or 5 days.Higher relative humidity or temperature was conducive to fungal growth.The orthogonal experiment revealed that the condition of“antibacterial composite,22±1℃and 45%-55%RH”had the strongest inhibiting impact on fungal growth.Logistic model,Gompertz model and square-root model were further developed to predict the fungal growth under different conditions.The results show that the Logistic model had high feasibility and accuracy,the Gompertz model was feasible with lower accuracy and the square-root model was feasible with high accuracy.Overall,this study facilitates the understanding of the DAF growth in air-conditioning ducts,which is important for real-time prediction and timely control of the fungal contamination.

Quantitative distribution of human exhaled particles in a ventilation room

Respiratory viruses can be attached to human exhaled particles and spread from person to person through respiratory activities.The purpose of this study is to obtain the quantitative description formula of human exhaled particles in the ventilated room through amount number of numerical simulation calculations and regression statistical analysis of the simulated data.In this study,a combination of numerical simulation and laboratory experiments was used,and the results were tallied preferably.Bacillus subtilis was released as a release source to investigate the migration and distribution of bioaerosol.The results show that under the condition of high air supply velocity,due to the disturbance of human respiration and airflow,the diffusion velocity of exhaled particles was faster and the diffusion range is larger than that of low air supply velocity within the same time frame.No matter where the location of the manikin was in the room,the exhaled particles would spread to the whole room in at least 900 s.The method used in this study could be used to predict the distribution of human exhaled particles concentration in different indoor spaces,such as public transport and hospitals.These findings could provide valuable reference for the location of indoor air purifiers,which plays a guiding role in the construction of a healthy indoor environment.

Aerosol containment by airflow in biosafety laboratories

In this paper,the progress and research related to aerosol containment by airflow in containment environments,e.g.,biosafety laboratories,are introduced from a mechanical engineering view.A good airdistribution strategy in the room,a reasonable and stable pressure gradient in the containment area,and a necessary buffer room comprise the integral parts for regulating the air flow and providing the necessary containment.An optimal air-distribution strategy would reduce the residence time of the bioaerosol in the lab room and lower the exposure risk of the work staff.The pressure difference between adjacent rooms provides sufficient isolation protection when the door is closed.Nevertheless,an unfavorable air exchange would occur when the door is open,owing to door movement,passing people,or a tiny temperature difference.A buffer room is therefore necessary to offset the negative impact and maintain the containment effect.