Effect of Micro-electrolysis and Micro-nano Bubbles Coupled with Peroxymonosulfate Treatment of Rural Domestic Sewage

With the continuous deepening of rural revitalization strategy and the increasingly strict sewage discharge standards,rural domestic sewage treatment technology is facing higher challenges and requirements.The combined process of micro-electrolysis+micro-nano bubbles coupled with peroxymonosulfate was constructed in this study,and the treatment effect and application value of this technology were explored with the actual rural domestic sewage as the treatment object.The experimental results showed that under the conditions of HRT of 120 min,PMS dosage of 0.15 mmol/L,pH=7,MBs air intake of 15 ml/min,current intensity of 15 A,and Fe/C mass ratio of 1:1,the removal rates of COD,ammonia nitrogen and total phosphorus can reach 88.55%,77.18%and 74.67%,respectively.Under the condition that the pH value of sewage was not adjusted,the non-biochemical simultaneous decarbonization,denitrification and phosphorus removal of rural domestic sewage can be achieved by micro-electrolysis and micro-nano bubbles coupled with peroxymonosulfate.The concentrations of effluent COD,ammonia nitrogen and total phosphorus met the requirements of the first level standard of the Discharge Standard of Water Pollutants for Rural Domestic Sewage Treatment Facilities(DB45T2413-2021).And the comprehensive operating cost was about 1.15 yuan/m 3.

Study on Temporal and Spatial Variation Characteristics of Water Quality in the Yujiang River and the Xunjiang River(Guigang Section)

Based on the data at 29 monitoring sites in the whole basin of the Yujiang River and the Xunjiang River in Guigang City during 2014-2021,the single-factor evaluation method and the modified Nemerow pollution index method were used to analyze temporal and spatial distribution characteristics of water quality in the Yujiang River and the Xunjiang River basins.The results showed that the Wusi River(the Yujiang River)and the Dahuang River(the Xunjiang River)had the best water quality,while water quality of the Duchong River(the Yujiang River)was the worst,and the proportion of inferior to class V reached 93%.The second was the Shepo River(the Xunjiang River),and the proportions of inferior to class V and below class IV were 21%and 64%.Comprehensive Nemerow pollution index was used to evaluate the water quality of the Yujiang River and the Xunjiang River during 2014-2021.Five tributary sections with worse water quality were the Duchong River,Xiajiangkou,the Chencun River,the Liyu River,and the Dongtang River,and NH3-N and TP exceeded the standard seriously.Among them,water quality of the Duchong River was the worst and was slightly improved during 2018-2021,but it still exceeded the standard seriously.The analysis showed that the main source of serious eutrophication in the basin was the increase of NH3-N and TP concentrations caused by agricultural non-point source emissions.

Characteristics of Surface Water Quality Affected by Agricultural Non-point Sources in Guigang City

[Objectives]To analyze the influence characteristics of surface water quality by agricultural non-point sources in Guigang City of Guangxi.[Methods]The daily concentration series of water quality indicators at three state-controlled monitoring stations in Guigang City from^(2)019 to 2021 was analyzed by using Daubechies(db)wavelet,and Morlet wavelet was used to analyze the daily average concentration of water quality indicators.Continuous wavelet transform(CWT)was used to analyze the monthly concentration series of water quality indicators at three state-controlled monitoring stations in Guigang City from^(2)014 to 2021.[Results]The Daubechies(db)wavelet analysis showed that the concentrations of COD_(Mn),TP,and TN had the maximum values during June-July and October-November,and there were spatial differences among monitoring stations(COD_(Mn) concentration exceeding the standard was the most serious in Shizui,and DO concentration not up to standard was the most in Thermal Power Plant,and NH_(3)-N,TP and TN exceeding the standard was the most in Wulin Ferry).Morlet results showed that principal period of wavelet variance graphs of COD_(Mn),NH_(3)-N,and TP was 340 d,and there was the same sub-period of 140 d,and principal period of wavelet variance graph of DO was 260 d.CWT results showed that COD_(Cr) had similar resonance periods of about 1-2 and 5-7 months;BOD 5 and COD_(Mn) was dominant by the resonance period of 1-4 months(2014-2017);DO had a similar resonance period of about 1-3 months;NH_(3)-N was dominant by the resonance period of 1-5 months.[Conclusions]The surface water quality of Guigang City was mainly affected by the residual nitrogen and phosphorus nutrients and pesticide residues from agricultural production activities.

Synergistic Treatment of Low-concentration Organic Waste Gas by Micro-nano Bubble Coordinated with Peroxymonosulfate

Continuous dynamic experiment was conducted for the treatment of low-concentration organic waste gas with xylene as a representative, using micro-nano bubble and peroxymonosulfate working in synergy. The degradation rule of xylene under different conditions such as the ORP value of the spray liquid, pH value of the spray liquid, liquid-gas ratio of the spray liquid, residence time of xylene, and initial concentration of xylene was investigated. The results showed that at a low concentration, the pH value of the spray liquid had little effect on the degradation rate of xylene. The degradation rate of xylene rose with the increase of the ORP value of the spray liquid, the liquid-gas ratio of the spray liquid, the residence time of xylene, and the initial concentration of xylene.

Research Advances in Net Primary Productivity of Terrestrial Ecosystem

The net primary productivity of vegetation reflects the total amount of carbon fixed by plants through photosynthesis each year. The study of vegetation net primary productivity is one of the core contents of global change and terrestrial ecosystems. This article reviews the current research status of net primary productivity of terrestrial vegetation, and comprehensively analyzes the advantages and disadvantages of three types of productivity estimation models, climate relative models, biogeochemical models, and light energy utilization models. The light energy utilization models have become the mainstream method for estimating vegetation net primary productivity because they can directly use remote sensing data. However, there are still many deficiencies in the estimation of vegetation net primary productivity, which need to be further improved and tested.

The Water Quality Evaluation in Balihe Lake Based on Principal Component Analysis

The water pollution situation in Balihe Lake, the biggest tributary of Shaying River Basin in Anhui Province, China, has brought a huge pressure on the improvement of water quality in Huai River. On October 16th, 2017, 11 major pollution indexes were observed at 15 sampling points in Balihe Lake. Based on the data experimentally measured, the water quality in Balihe Lake was analyzed utilizing the Principal Component Analysis (PCA) of SPSS. The result suggested that the major components were oxygenated pollutants, water eutrophication pollutants and ammonia nitrogen, in which oxygenated pollutants played a dominant role. In addition, the upper part of Balihe Lake suffered serious situation and needed a focus on oxygenated pollutants.

Research and Experiment on Performance Stability of Facility Green-house Environmental Monitoring System

At present,the safety and stability of most facility greenhouse environment monitoring systems are seldom considered. In order to improve the stability of data transmission in environment and prevent the system failure caused by the fault of coordinator,a mechanism based on Zigbee coordinator to improve the stability of the whole system is proposed to ensure the security of wireless data transmission. Finally,the system is tested,and the results show that the system can effectively ensure the fault-free transmission of collected environmental data.

Engineering of hollow polymeric nanosphere-supported imidazolium-based ionic liquids with enhanced antimicrobial activities

The design of stable,efficient and processable bactericidal materials represents a significant challenge for combating multidrugresistant bacteria in a variety of engineering fields.Herein,we report a facile strategy for the preparation of hollow polymeric nanosphere(HPN)-supported imidazolium-based ionic liquids(denoted as HPN-ILs)with superior antimicrobial activities.HPNILs were tailored by moderate Friedel−Crafts polymerization followed by the sequential covalent bonding of imidazole and bromoalkene.The resultant HPN-ILs have uniform hollow spherical morphology,an adequate surface area,and excellent physicochemical stability.Furthermore,they are highly active against both Gram-positive and Gram-negative bacteria and exhibit typical time/dosage-dependent antibacterial activities.The rational combination of porous HPNs and antibacterial ILs to generate an all-in-one entity may open new avenues for the design and fabrication of efficient bacteriostatic agents.Moreover,HPN-ILs have good biocompatibility and can also be loaded onto diverse matrices,and thus could extend their practical bactericidal application in the potential biomedical-active field.

Spray-coated electret materials with enhanced stability in a harsh environment for an MEMS energy harvesting device

The charge stability of electret materials can directly affect the performance of electret-based devices such as electrostatic energy harvesters.In this paper,a spray-coating method is developed to deposit an electret layer with enhanced charge stability.The long-term stability of a spray-coated electret is investigated for 500 days and shows more stable performance than a spin-coated layer.A second-order linear model that includes both the surface charge and space charge is proposed to analyze the charge decay process of electrets in harsh environments at a high temperature(120°C)and high humidity(99%RH);this model provides better accuracy than the traditional deep-trap model.To further verify the stability of the spray-coated electret,an electrostatic energy harvester is designed and fabricated with MEMS(micro-electromechanical systems)technology.The electret material can work as both the bonding interface and electret layer during fabrication.A maximum output power of 11.72μW is harvested from a vibrating source at an acceleration of 28.5 m/s2.When the energy harvester with the spray-coated electret is exposed to a harsh environment(100°C and 98%RH),an adequate amount of power can still be harvested even after 34 h and 48 h,respectively.