污水处理智能控制与优化控制方法及应用

论述目前污水处理中的智能控制与优化控制方法的研究与应用现状,对模糊控制技术、神经网络软测量与控制、优化控制等方法进行了分析,指出在污水生物处理中引入智能控制是一种提高处理效率、降低运行成本的有效方法.污水处理最优控制能使系统运行稳定可靠,出水水质达到预定标准,而且使出水水质满足要求不增加处理成本.     

Assessing microbial and chemical exposure risks of Giardia in indoor swimming pool water disinfected by chlorine

Swimming pools adopt chlorination to ensure microbial safety. Giardia has attracted attention in swimming pool water because of its occurrence, pathogenicity, and chlorine resistance. To control Giardia concentrations in pool water and reduce the microbial risk, higher chlorine doses are required during disinfection. Unfortunately, this process produces carcinogenic disinfection byproducts that increase the risk of chemical exposure. Therefore, quantitatively evaluating the comparative microbial...     

Investigation of PM2.5 pollution during COVID-19 pandemic in Guangzhou, China

The COVID-19 pandemic has raised awareness about various environmental issues,including PM_2.5 pollution.Here,PM_2.5 pollution during the COVID-19 lockdown was traced and analyzed to clarify the sources and factors influencing PM_2.5 in Guangzhou,with an emphasis on heavy pollution.The lockdown led to large reductions in industrial and traffic emissions,which significantly reduced PM_2.5 concentrations in Guangzhou.Interestingly,the trend of PM_2.5     

Penicillin fermentation residue biochar as a high-performance electrode for membrane capacitive deionization

● We have provided an activated method to remove the toxicity of antibiotic residue. ● PFRB can greatly improve the salt adsorption capacity of MCDI. ● The hierarchical porous and abundant O/N-doped played the key role for the high-capacity desalination. ● A new field of reuse of penicillin fermentation residue has been developed. Membrane capacitive deionization (MCDI) is an efficient desalination technology for brine. Penicillin fermentation residue biochar (PFRB) possesses a hierarchical porous and O/N-doped structure which could serve as a high-capacity desalination electrode in the MCDI system. Under optimal conditions (electrode weight, voltage, and concentration) and a carbonization temperature of 700 °C, the maximum salt adsorption capacity of the electrode can reach 26.4 mg/g, which is higher than that of most carbon electrodes. Furthermore, the electrochemical properties of the PFRB electrode were characterized through cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) with a maximum specific capacitance of 212.18 F/g. Finally, biotoxicity tests have showed that PFRB was non-biotoxin against luminescent bacteria and the MCDI system with the PFRB electrode remained stable even after 27 adsorption–desorption cycles. This study provides a novel way to recycle penicillin residue and an electrode that can achieve excellent desalination.     

Asian dust events observed by a 20-m monitoring tower in Mongolia during 2009

A 20-m Asian dust monitoring tower was installed at Erdene in Dornogobi, Mongolia in later 2008, which is one of the high Asian dust source regions in the Asian domain, to investigate meteorological conditions for the dust events. The tower was equipped with meteorological sensors (temperature, humidity and wind speed at four levels, precipitation and pressure near the surface), radiation sensors (solar radiation, net radiation) and soil measurement sensors (soil moisture and soil temperature at three levels and soil heat flux at one level) and turbulent measurement (sonic anemometer) at the 8 m height and PM₁₀ concentration measurement (beta guage) at the 3 m height. Measurement was made for a full year of 2009. The observed data indicated that dust events occur all year round with the maximum hourly mean maximum concentration of 4107 μg m^?3 in the early May to a minimum of 92 μg m^?3 in later August. It was found that the dust concentration at this site is directly related to the wind speed exceeding the threshold wind speed (likewise the corresponding friction velocity) during the winter to early spring. However, the observed dust concentration is not only related to the wind speed exceeding the threshold wind speed but also to the Normalized Difference Vegetation Index (NDVI) during the late spring to the late autumn due to the growth of vegetation. It was also found that the surface soil moisture content does not affect the dust concentration due to the relatively short residence time of the soil moisture in the surface soil. The presently monitored data can be used to verify parameters used in the Asian Dust Aerosol Model (ADAM) that is the operational forecasting dust model in the Korea Meteorological Administration (KMA).     

Toxicity potentials from waste cellular phones,and a waste management policy integrating consumer,corporate, and government responsibilities

Cellular phones have high environmental impact potentials because of their heavy metal content and current consumer attitudes toward purchasing new phones with higher functionality and neglecting to return waste phones into proper take-back systems. This study evaluates human health and ecological toxicity potentials from waste cellular phones; highlights consumer, corporate, and government responsibilities for effective waste management; and identifies key elements needed for an effective waste management strategy. The toxicity potentials are evaluated by using heavy metal content, respective characterization factors, and a pathway and impact model for heavy metals that considers end-of-life disposal in landfills or by incineration. Cancer potentials derive primarily from Pb and As; non-cancer potentials primarily from Cu and Pb; and ecotoxicity potentials primarily from Cu and Hg. These results are not completely in agreement with previous work in which leachability thresholds were the metric used to establish priority, thereby indicating the need for multiple or revised metrics. The triple bottom line of consumer, corporate, and government responsibilities is emphasized in terms of consumer attitudes, design for environment (DfE), and establishment and implementation of waste management systems including recycling streams, respectively. The key strategic elements for effective waste management include environmental taxation and a deposit-refund system to motivate consumer responsibility, which is linked and integrated with corporate and government responsibilities. The results of this study can contribute to DfE and waste management policy for cellular phones.     

Development of a high-efficiency rotary dryer for sewage sludge

A rotary drum dryer having an internal rotating body was designed and tested in this study. It was shown that the developed dryer is effective for drying sewage sludge. The best operating conditions in the dryer were low energy input and almost 10% moisture content. The conditions are 255°C for the rotary drum temperature, 17 min for the sludge residence time, and 55 kg/m³ h for the dryer load. Under these conditions, the drying efficiency was 84.8%. The average diameter of dried sludge was less than 8 mm, and the weight reduction rate was 80%. Parametric screening studies achieved the following results. The drying efficiency increased with the increase of the internal temperature and the sludge residence time in the rotary drum, while the drying efficiency decreased when increasing the dryer load. In addition, it was shown that NH₃ and CO₂ were the primary components released from the sewage sludge drying process. The amounts of both of these components increased when the rotary drum temperature was increased.     

Storage stability of injection-molded starch-zein plastics under dry and humid conditions

Corn starch and zein mixtures (4 : 1 dry weight) were extruded and injection-molded in the presence of plasticizers (glycerol and water). Tensile strength and percentage elongation of the molded plastics were measured before and after 1 week of storage under a dry or humid condition (11 or 93% RH). With 10–12% glycerol and 6–8% water, injection-molded plastics had relatively good tensile properties (20- to 25-MPa tensile strength and 3.5–4.7% elongation). But while exposed to dry conditions (11% RH), the molded plastics lost weight (0.5–1.5% in 7 days) and became very brittle, with significant decreases in tensile strength and elongation. Partial replacement (5–10%) of starch with a maltodextrin (average DE 5) reduced the glass transition and melting temperatures of the starch-zein mixture as well as the dry storage stability. Using potato starch instead of corn starch significantly improved the dry storage stability of the injection-molded starch-zein plastics (18- vs 11-MPa tensile strength). Anionic corn starches with a maleate or succinate group (DS<0.01) produced injection-molded plastics with improved tensile properties and storage stability. Plastics prepared from the starch maleate and zein mixture retained the strength during 1 week of dry storage without a significant change (26-MPa tensile strength and 3.7% elongation after 1 week of storage).Paper presented at the Bio/Environmentally Degradable Polymer Society—Second National Meeting, August 19–21, 1993, Chicago, Illinois.Journal paper No. J-15561 of the Iowa Agriculture and Home Economics Experiment Station, Ames, Iowa, Project No. 2863.     

EFFECTS OF INITIAL ABSTRACTION AND URBANIZATION ON ESTIMATED RUNOFF USING CN TECHNOLOGY1

ABSTRACT: Few studies have been conducted to explore the effects of initial abstraction on estimated direct runoff despite the widespread use of the curve number (CN) method in many hydrologic models to estimate direct runoff. In this study, use of a 5 percent ratio of initial abstraction (I_a) to storage (S) to estimate daily direct runoff with modified CN values for a 5 percent I_a/S value was investigated using the Long‐Term Hydrologic Impact Assessment (L‐THIA) geographic information system (GIS). In addition, the effects on estimated runoff of altering the hydrologic soil group due to urbanization were investigated. The L‐THIA model was applied to the Indiana Little Eagle Creek watershed with 5 percent and 20 percent I_a/S values, considering hydrologic soil group alteration due to urbanization. The results indicate that uses of a 5 percent l_a/S and modified CN values and Hydrologic Soil Group D for urbanized areas in model runs can improve long term direct runoff prediction.