Design and Implementation of Agricultural Information Acquisition System Based on ZigBee and Qt

This paper introduces the design and implementation of agricultural products information collection system based on Qt and ZigBee platform. It consists of three subsystems mainly based in acquisition of images, temperature and humidity values which are passed to the regional gateway. The regional gateway is equipped with embedded Linux operating system and deployed Qt runtime library. The function of transmitting the static image of agricultural products and the temperature and humidity to the regional gateway through the ZigBee Wireless Sensor Network is realized, the pH value, electrical conductivity and light intensity of the growth environment of agricultural products were measured by using Qt library combined with sensor cluster, it can store, display and query the image, electrical conductivity and other parameters in the regional gateway.

A ZigBee-Based Acquisition System for Agricultural Environment Information with Low Power and High Reliability

In order to guarantee the safety of products at modern agriculture, the whole factors of the environment of agricultural production process need to be monitored. That needs to collect a variety of environmental information. In this paper, based on ZigBee technology, a system for crop growth environment information and image information acquisition is implemented. System network scheme can reduce the interchannel interference and enhance ZigBee communication quality. In the process of transmission, the transmission of the image data uses a coding scheme based on historical data comparison. For the image transmission, an intelligent transmission scheme based on generating Feedback Report is proposed, which takes both the quality and efficiency into consideration. Based on these schemes, the system designed in this paper can realize efficient and reliable transmission of agricultural environmental information.

Data-driven systematic analysis of waterborne viruses and health risks during the wastewater reclamation process

Waterborne viral epidemics are a major threat to public health.Increasing interest in wastewater reclamation highlights the importance of understanding the health risks associated with potential microbial hazards,particularly for reused water in direct contact with humans.This study focused on identifying viral epidemic patterns in municipal wastewater reused for recreational applications based on long-term,spatially explicit global literature data during 2000e2021,and modelled human health risks from multiple exposure pathways using a well-established quantitative microbial risk assessment methodology.Global median viral loads in municipal wastewater ranged from 7.92×10^(4)to 1.4×10^(6)GC L^(-1)in the following ascending order:human adenovirus(HAdV),norovirus(NoV)GII,enterovirus(EV),NoV GI,rotavirus(RV),and severe acute respiratory syndrome coronavirus 2(SARSCoV-2).Following secondary or tertiary wastewater treatment,NoV GI,NoV GII,EV,and RV showed a relatively higher and more stable log reduction value with medians all above 0.8(84%),whereas SARSCoV-2 and HAdV showed a relatively lower reduction,with medians ranging from 0.33(53%)to 0.55(72%).A subsequent disinfection process effectively enhanced viral removal to over 0.89-log(87%).The predicted event probability of virus-related gastrointestinal illness and acute febrile respiratory illnesses in reclaimed recreational water exceeded the World Health Organization recommended recreational risk benchmark(5%and 1.9%,respectively).Overall,our results provided insights on health risks associated with reusing wastewater for recreational purposes and highlighted the need for establishing a regulatory framework ensuring the safety management of reclaimed waters.

移民对于安置政策的反应:厘清信息渠道的影响路径

对于那些必须离开故土重新安家的移民而言,大众媒体和人际沟通是其获取政策信息的重要渠道,并将影响他们对于安置政策的态度与反应。关于信息渠道与集体反对倾向之间的影响机制,现有研究分别从政府信任与感知收益的角度提出了两种解释路径。但是,如何根据这两种解释路径中涉及的不同信息渠道来预测移民的集体反对倾向,仍有待研究。本文聚焦中国的移民安置政策,构建了一个旨在厘清信息渠道与移民集体反对倾向之间因果关系的综合性理论框架,并结合来自中国A市三个镇的调查数据,通过结构方程模型分析对上述因果机制进行了实证检验。结果表明,相较于感知收益,政府信任对于该因果机制的解释更有力;相较于大众媒体,人际沟通更有助于降低移民的集体反对倾向。此外,本文还讨论了这项研究在中国移民安置的政策宣传与政府信任构建方面的现实意义。

Evaluation of the secondary structures of protein in the extracellular polymeric substances extracted from activated sludge by different methods

The changes of protein secondary structures in the extracellular polymeric substances(EPS) extracted from activated sludge by four different methods were studied by analyzing the amide I region(1700–1600 cm-1) of the Fourier transform infrared spectra and model protein test. The results showed the molecular weight distribution of organic matter extracted by centrifugation, heating and cation exchange resin(CER) was similar, while the EPS extracted by centrifugation(Control) and CER had similar fluorescent organic matter. The protein secondary structures of extracted EPS by the four methods were different. The similarities of protein secondary structures between the EPS extracted by CER with the Control were the highest among the four extracted EPS. Although the EPS yield extracted by formaldehyde + NaOH method were the highest, its protein secondary structures had the lowest similarity with those extracted by the Control. Additionally, the effects of centrifugation and CER extraction on the secondary structures of bovine serum albumin were also lower than that of other extraction processes. CER enables the second maximum extraction of EPS and maximum retention of the original secondary structure of proteins.

Reduction and characterization of bioaerosols in a wastewater treatment station via ventilation

Bioaerosols from wastewater treatment processes are a significant subgroup of atmospheric aerosols. In the present study,airborne microorganisms generated from a wastewater treatment station（WWTS） that uses an oxidation ditch process were diminished by ventilation.Conventional sampling and detection methods combined with cloning/sequencing techniques were applied to determine the groups,concentrations,size distributions,and species diversity of airborne microorganisms before and after ventilation. There were 3021 ± 537 CFU/m3 of airborne bacteria and 926 ± 132 CFU/m3 of airborne fungi present in the WWTS bioaerosol.Results showed that the ventilation reduced airborne microorganisms significantly compared to the air in the WWTS. Over 60% of airborne bacteria and airborne fungi could be reduced after4 hr of air exchange. The highest removal（92.1% for airborne bacteria and 89.1% for fungi） was achieved for 0.65–1.1 μm sized particles. The bioaerosol particles over 4.7 μm were also reduced effectively. Large particles tended to be lost by gravitational settling and small particles were generally carried away,which led to the relatively easy reduction of bioaerosol particles0.65–1.1 μm and over 4.7 μm in size. An obvious variation occurred in the structure of the bacterial communities when ventilation was applied to control the airborne microorganisms in enclosed spaces.

Investigation on mechanism of phosphate removal on carbonized sludge adsorbent

For the removal of phosphate（PO43-） from water, an adsorbent was prepared via carbonization of sewage sludge from a wastewater treatment plant： carbonized sludge adsorbent（CSA）. The mechanism of phosphate removal was determined after studying the structure and chemical properties of the CSA and its influence on phosphate removal. The results demonstrate that phosphate adsorption by the CSA can be fitted with the pseudo second-order kinetics and Langmuir isotherm models, indicating that the adsorption is single molecular layer adsorption dominated by chemical reaction. The active sites binding phosphate on the surface are composed of mineral particles containing Si/Ca/Al/Fe. The mineral containing Ca, calcite, is the main factor responsible for phosphate removal. The phosphate removal mechanism is a complex process including crystallization via the interaction between Ca2＋ and PO43-; formation of precipitates of Ca2＋, Al3＋, and PO43-; and adsorption of PO43-on some recalcitrant oxides composed of Si/Al/Fe.

Flow field and dissolved oxygen distributions in the outer channel of the Orbal oxidation ditch by monitor and CFD simulation

In the Orbal oxidation ditch, denitrification is primarily accomplished in the outer channel. However, the detailed characteristics of the flow field and dissolved oxygen （DO） distribution in the outer channel are not well understood. Therefore, in this study, the flow velocity and DO concentration in the outer channel of an Orbal oxidation ditch system in a wastewater treatment plant in Beijing （China） were monitored under actual operation conditions. The flow field and DO concentration distributions were analyzed by computed fluid dynamic modeling. In situ monitoring and modeling both showed that the flow velocity was heterogeneous in the outer channel. As a result, the DO was also heterogeneously distributed in the outer channel, with concentration gradients occurring along the flow direction as well as in the cross-section. This heterogeneous DO distribution created many anoxic and aerobic zones, which may have facilitated simultaneous nitrificafion-denitrification in the channel. These findings may provide supporting information for rational optimization of the performance of the Orbal oxidation ditch.

Microbial aerosol particles in four seasons of sanitary landfill site:Molecular approaches,traceability and risk assessment

Landfill sites are regarded as prominent sources of bioaerosols for the surrounding atmosphere.The present study focused on the emission of airborne bacteria and fungi in four seasons of a sanitary landfill site.The main species found in bioaerosols were assayed using high-throughput sequencing.The Source Tracker method was utilized to identify the sources of the bioaerosols present at the boundary of the landfill site.Furthermore,the health consequences of the exposure to bioaerosols were evaluated based on the average daily dose rates.Results showed that the concentrations of airborne bacteria in the operation area(OPA)and the leakage treatment area(LTA)were in the range of(4684±477)–(10883±1395)CFU/m^(3) and(3179±453)–(9051±738)CFU/m^(3),respectively.The average emission levels of fungal aerosols were 4026 CFU/m^(3) for OPA and 1295 CFU/m^(3) for LTA.The landfill site received the maximum bioaerosol load during summer and the minimum during winter.Approximately 41.39%–86.24%of the airborne bacteria had a particle size of 1.1 to 4.7μm,whereas 48.27%–66.45%of the airborne fungi had a particle size of more than 4.7μm.Bacillus sp.,Brevibacillus sp.,and Paenibacillus sp.were abundant in the bacterial population,whereas Penicillium sp.and Aspergillus sp.dominated the fungal population.Bioaerosols released from the working area and treatment of leachate were the two main sources that emerged in the surrounding air of the landfill site boundary.The exposure risks during summer and autumn were higher than those in spring and winter.

An innovative integrated system utilizing solar energy as power for the treatment of decentralized wastewater

This article reports an innovative integrated system utilizing solar energy as power for decentralized wastewater treatment, which consists of an oxidation ditch with double channels and a photovoltaic （PV） system without a storage battery. Because the system operates without a storage battery, which can reduce the cost of the PV system, the solar radiation intensity affects the amount of power output from the PV system. To ensure that the power output is sufficient in all different weather conditions, the solar radiation intensity of 78 W/m 2 with 95% confidence interval was defined as a threshold of power output for the PV system according to the monitoring results in this study, and a step power output mode was used to utilize the solar energy as well as possible. The oxidation ditch driven by the PV system without storage battery ran during the day and stopped at night. Therefore, anaerobic, anoxic and aerobic conditions could periodically appear in the oxidation ditch, which was favorable to nitrogen and phosphate removal from the wastewater. The experimental results showed that the system was efficient, achieving average removal efficiencies of 88% COD, 98% NH 4 ＋ -N, 70% TN and 83% TP, under the loading rates of 140 mg COD/（g MLSS·day）, 32 mg NH 4 ＋ -N/（g MLSS·day）, 44 mg TN/（g MLSS·day） and 5 mg TP/（g MLSS·day）.