Management of process performance at low water temperatures in respect of filamentous organisms

The management of sludge-settling properties in Nordic conditions is of importance during the low temperature (spring) season because of the peak settler load. A survey was made in 10 Finnish waste water treatment plants(WWTP‘ s) and the total extended filament length and DSVI in haft of the plants exceeded the limits, which indicates sludge bulking( 15 km/g SS and 150 ml/g respectively). The dominant organism was Microthrix parvicella, the abundance of which was 59.22% of total extended filament length on average.Chemicals were tested to control the filaments, and it was found that special attention has to be paid to maintaining the nitrification at low temperature. A dosage of(H2O2-besed) oxidants controlled the growth of Microthrix parvicella effectively and rapidly, whereas with the use of aluminium hydroxidechloride a 2 to 5-week period was needed to decrease the filament length.     

Estimation of chemical concentration due to fugitive emissions during chemical process design

Fugitive emissions are not an environmental concern alone, but are also a health concern. From occupational health standpoint, fugitive emissions are the main sources of origin of the continuous exposure to workers. Operating plants regularly measure release and concentration levels through a plant-monitoring program. However, for processes which are still ‘on paper’, predictive estimation methods are required. Therefore, three methods for estimating concentration of the fugitive emissions are presented for the process development and design phases of petrochemical processes. The methods estimate the fugitive emission rates and plant plot dimensions resulting to fugitive emission concentrations. The methods were developed for the type and amount of information available in three process design stages; conceptual design, preliminary process design, and detailed process design. The methods are applied on a real benzene plant; the estimated benzene concentrations are compared to the actual concentration measured at the plant. The results show that as the information mounts up during design, the concentration estimate becomes more accurate. The results indicate that the methods presented provide simple estimates of fugitive emission-based concentrations during the design stages.     

Inherent occupational health assessment during basic engineering stage

Each year more people die from work-related diseases than are killed in industrial accidents. Therefore it is essential to evaluate occupational health aspect during the process design. Early evaluation of safety, health, and environmental (SHE) performance is advantageous, since the opportunities to make the process inherently benign are greater and the cost therefore lower. The methods for occupational health assessments need to be tailored to specific design stages, since the data availability is changing as the design proceeds. In this paper, an index-based method called the Occupational Health Index (OHI) is presented for the basic engineering stage. The OHI is the final of the three methods in series proposed for health assessment in development and design stages. The OHI is based on the information available in piping and instrumentation diagrams (PIDs) and the plot plan. Four health aspects are considered; chronic inhalation risks to noncarcinogens and carcinogens, acute inhalation risk, and dermal/eye risk. The index is demonstrated on separation system of a toluene hydrodealkylation process. The assessment results allow the level of occupational health risks to be evaluated, the sources of exposures be detected, and corrective actions taken in a focused way.     

Inherent occupational health assessment during preliminary design stage

Chemical process routes can already be assessed as early as in the development and design phases. Process screening should not look at economic and technical aspects only, but also the safety, health, and environmental performances. In this paper, a method called the Health Quotient Index (HQI) is presented for the preliminary process design phase. The HQI provides a simple approach to quantify workers' health risk from exposure to fugitive emissions e.g. in petrochemical plants. The method utilizes process data from flow sheet diagram, which is already available at the preliminary design stage. Since the mechanical details of the process are still unknown, a database of the precalculated fugitive emissions for typical operations in chemical plants was created to simplify the assessment. The HQI can be used to rank alternative process concepts or to quantify the risk level of processes. As a case study, six process routes for producing methyl methacrylate are discussed. Three health indexes are compared in the case study. The HQI is able to highlight the difference of hazard levels between the routes better as a result of more detailed assessment of the exposures.     

Investment Evaluation of an Integrated Steel Mill using Multiple Criteria

A conventional steel manufacturing process generates considerable amounts of reject streams and secondary raw material. These streams are either recycled back to the process or treated as waste. Recycling affects negatively on the production yield and on the controllability of unit operations. Waste represents considerable cost unless utilized in another production process as raw material. In these streams, there exists a potential to use the chemical elements more effectively. Therefore, it might be interesting to find an economical technical solution to collect the streams and increase steel production.

Investments on process equipment are typically evaluated using conventional economic figures, like payback time, Net Present Value (NPV) etc. The problem with these practices is, that they consider only numerical aspects. Non-numerical and non-economical criteria are hard to cater to the evaluation. Still, they may affect on the investment profitability in the long run. Such criteria include environmental friendliness or the aspects of process integration.

The article presents a comparison of a conventional steel manufacturing process with one reject stream processing alternative. A target in the process modification is to optimize the use of material and energy within the site. The comparison is based on a balanced set of criteria that affect on the efficiency of an investment. The use of these criteria is a part of the new methodology that has been developed to evaluate investments on integrated process sites. In addition to the criteria, the complete methodology includes: 1) connection of company’s strategic issues into technical design and decision making, 2) optimization of the process and calculation of process potentials (differences in the performance values between the existing process and the modified process) through the use of process integration methodologies and 3) use of decision-making aids. The research is a part of Finnish National Technology Program, “Process-Integration 2000–2004”.     

瑞典区域气候模拟计划(SWECLIM)综述

瑞典区域气候模拟计划(SWECLIM)是一个历时6年半的国家研究网络计划,该研究网络主要涉及区域气候模拟、区域气候变化预测以及水文影响评估,并且为广大的利益相关人士提供相应信息.大部分研究活动主要针对北欧区域气候系统.最终促使建立一个先进的大气-海洋-水文相耦合的区域气候模型系统和一套区域气候变化预测体系,并促成了相关数据的积累和相关过程研究的进步.反过来,作为对不同社会部门影响分析的一个起点,这些也可以用来作为信息源和为教育服务,而且还为国际气候研究做出了贡献.     

生态城市中的环境艺术可行性

干净、健康的生态城市是当前全球环保意识逐步增强的趋势下人们所普遍期望的生存空间；环境艺术则是满足人们在视觉欣赏、心理愉悦等精神层面的需求。本文就环境艺术的特定概念及其在生态城市中的几种可行性进行简单介绍，通过结合国际上一些案例，让我们更好地了解到环境艺术如何在生态城市空间中得以充分展现。     

DNA-based prenatal diagnosis of the infantile form of neuronal ceroid lipofuscinosis (INCL,CLN1)

Eleven fetuses at risk for the infantile form of neuronal ceroid lipofuscinosis (INCL, CLN1) were studied using DNA markers and the results were compared with the results of electron microscopy (EM) of chorionic villus specimens from pregnancies in the first or early second trimester of pregnancy. In four cases, the prenatal diagnosis was made independently with both methods, and in seven cases, the EM diagnosis was confirmed postnatally or from autopsy material using RFLP analysis. The two methods gave concordant results in all cases. The DNA analysis based on RFLP haplotypes also for the first time facilitates reliable carrier diagnostics. RFLP analysis based on polymorphic markers closely linked to the INCL locus is now available for prenatal diagnosis of this fatal brain disease, whose biochemical background is totally unknown and for which no treatment is available.