This research utilized food waste (FW) as substrate, innovatively developed a directional multienzyme applied for accelerating FW hydrolysis and composting, and an in situ enzymatic hydrolysis combining in composting has been developed to manage FW. Results showed that the composting was achieved at 4 days and the humification index was increased by 2.60 compared with that of without enzymatic hydrolysis. FTIR analysis revealed that following multienzyme pretreatment, the primary constituents of FW, including protein, starch and lipid, underwent structural breakdown, among which protein exhibited the higher susceptibility to multienzyme action and was the first to disintegrated, and the structure also became looser. Moreover, the total antibiotic resistance gene (ARGs) was reduced more than 90 % in the proposed composting process. Analysis of microbial communities and metagenomes showed that multienzyme pretreatment reshaped microbial communities towards favoring FW hydrolysis and humification. The engineering application analysis further implied that the proposed composting approach is scale flexible, engineering applicable, economic viability and environmentally sustainability. It was anticipated that this study has the potential to trigger a paradigm shift in future in-situ treatment of FW to achieve full resource recovery towards zero solid discharge.
Hydrothermal treatment of septic sludge can result in the transfer of significant amounts of dissolved organic matter (DOM) into the hydrothermal liquid (HL). However, there is a lack of research exploring the relationship between temperature-sensitive fractions of DOM in HL and ecological risks. In this study, spectroscopic techniques combining two-dimensional correlation spectroscopy (2D-COS), self-organizing maps (SOM) and structural equation modeling (SEM), respectively, were employed to investigate temperature-sensitive DOM and its potential correlation with phytotoxicity at five process temperatures (180-340 °C). The findings revealed that DOM content peaked at 260 °C, measuring 7625 mg·CL-1. At peak levels, the concentrations of chemical oxygen demand, ammonium nitrogen, total nitrogen, and total phosphorus in the HL reached 16900 mg L-1, 34.8 mg L-1, 1920 mg L-1 and 756 mg L-1, respectively. Results from EEM-PARAFAC-SOM indicated that temperature significantly influences the variations in fluorescent components within DOM. Additionally, 2D-COS analysis identified conjugated structures and critical turning points at 220 °C and 300 °C. Notably, the -CO-NH- functional group, which is closely associated with aromatic protein II, exhibited the highest sensitivity to temperature changes. Wheat seed germination experiments revealed that the DOM sample at 180 °C exhibited the most pronounced inhibition of wheat root length, while demonstrating the least effect on germination. In contrast, seed growth was most severely impaired at 340 °C. SEM analysis revealed the influence of temperature-both direct and indirect-on the properties of DOM, identifying aromatic protein I as the primary determinant limiting seed germination. This research provides valuable insights for the management and utilization of HL.
Driving cycle offers a comprehensive understanding of operational features throughout the waste collection and transportation (C&T) process, which is critical for optimizing waste management aiming at reducing energy use and environmental pollution. In this study, the Micro-trip method, combined with principal component and cluster analysis, was adopted to divide the C&T process into five operational phases. Considering diverse waste types and C&T modes, four driving cycles were synthesized for garbage trucks. The average speeds of garbage truck cycles are considerably lower, coupled with prolonged idle durations, marking a substantial deviation from standard cycles. Additionally, the OpMode-bin method was employed to estimate fuel consumption for both garbage truck cycles and standard cycles. The results reveal that using standard cycles generally results in an underestimation of fuel consumption by 20 % to 30 %, which highlights the necessity of developing specific driving cycles to ensure accurate fuel use and emission quantification for garbage trucks.
Leaching of per- and polyfluoroalkyl substances (PFAS) during the post-consumer disposal of food contact materials (FCMs) poses a potential environmental threat but has seldom been evaluated. This study characterized the leaching behavior of PFAS and unidentified precursors from six common FCMs and assessed the impact of environmental conditions on PFAS release during disposal. The total concentration of 21 PFAS ranged from 3.2 to 377 ng/g in FCMs, with PFAS leachability into water varying between 1.1-42.8 %. Increasing temperature promoted PFAS leaching, with leached nine primary PFAS (& sum;(9)PFAS) reaching 46.3, 70.4, and 102 ng/L at 35, 45, and 55 degree celsius, respectively. Thermodynamic analysis (triangle G>0, triangle H>0, and triangle S<0) indicated hydrophobic interactions control PFAS leaching. The presence of dissolved organic matter in synthetic leachate increased the leached & sum;(9)PFAS from 47.1 to 103 ng/L but decreased PFBS, PFOS, and 6:2 FTS leaching. The total release of seven perfluorocarboxylic acids (& sum;7PFCAs) from takeaway food packaging waste was estimated to be 0.3-8.2 kg/y to landfill leachate and 0.6-15.4 kg/y to incineration plant leachate, contributing 0.2-4.8 % and 0.1-3.2 % of total & sum;7PFCAs in each leachate type. While the study presents a refined methodology for estimating PFAS release during disposal, future research is needed on the indirect contribution from precursors.
This study used food waste (FW) as the substrate, under the co-culture system, innovatively developed the oriented and high matching degree microbial consortium-based compound enzyme (MCE) used for promoting FW hydrolysis and anaerobic digestion (AD). It was found that the highest hydrolysis efficiency and substrate biodegradability could be obtained after 1:100 MCE (i.e. the inoculation ratio of Aspergillus oryzae CICC 40214 as protease generator and Aspergillus niger CICC 40294 as amylase generator was 1:100) pretreatment, thereby harvesting the highest biomethane yield of 522.61 mL/g VS. The dissection of FTIR results indicated that the structure of main components of starch, protein and lipid in FW was destructed after MCE pretreatment, of which the protein was more susceptible to MCE and disintegrated first, while its structure also became looser. XPS C1s spectra and N1s spectra showed that the C-(C/H) and protein-N of the enzyme pretreated solid were respectively decreased from 77.82 % to 69.19 % and 69.43 % to 40.07 %, which further implied that more carbohydrates and proteins were released from solid phase to liquid phase after MCE pretreatment. The microbial community and metagenome analysis illustrated that MCE pretreatment regulated the microbial communities lead to a shift in the favorable direction of biomethane production. While based on the changes in gene abundance, the deciphering of global metabolic pathways revealed that the 80 %, 60 %, 75 % and 86 % of the functional genes related to glycolysis, amino acid metabolism, TCA cycle and methane metabolism were respectively intensified after 1:100 MCE pretreatment, thereby achieving the maximized biomethane yield.
Microbial electrolysis cell-assisted thermophilic anaerobic digestion (MEC-TAD) is a promising method to improve anaerobic co-digestion efficiency; however, its application is restricted by high energy consumption. To improve the energy use efficiency of MEC-TAD, this study investigated the effect of different intermittent energization strategies on thermophilic co-digestion performance. Results revealed that an 18 h-ON/6h-OFF energization schedule resulted in the fastest electron transfer rate and the highest methane yield (364.3 mL/g VS). Mechanistic analysis revealed that 18 h-ON/6h-OFF resulted in the enrichment of electroactive microorganisms and increased abundance of enzyme-coding genes associated with energy metabolism (ntp, nuo, atp), electron transfer (pilA, nfrA2, ssuE), and the hydrogenotrophic methanogenic pathway. Finally, energy balance analysis revealed that 18 h-ON/6h-OFF had the highest net energy benefit (2.52 kJ) and energy conversion efficiency (110.76 %). Therefore, intermittent energization of MEC-TAD using an 18 h-ON/6h-OFF schedule can provide improved performance and more energy savings.
源分离旱厕非常适用于我国高寒旱农村地区的厕所改造,然而,源分离尿液在收集和长期储存过程中易因尿素水解而造成氨氮挥发损失以及异味等问题,因此,以尿液作为液体肥施用为目标开展了我国高寒旱地区尿液碱性稳定化研究.结果表明,pH越高、温度越低,尿液中尿素水解越容易被抑制,尿液越容易长期稳定,同时尿素水解活性强时,需提高pH以强化尿素水解的抑制.与草木灰相比,Ca(OH)2和CaO更适用于尿液的长期稳定化,Ca(OH)2投加量为5.2g/L时,尿液pH调节为11.0,可以在180 d有效实现尿液稳定化.当尿液施用量低于1.5 L/m2时,相比施用水解尿液,施用稳定化尿液带来的土壤盐碱化风险更低.
实地踏勘了 5个省份的96座公厕,从设施设备、人性化服务、卫生环境、污水排放情况等4个方面进行探讨.依据5个省份1203份线上、线下调查问卷,从"厕所革命"进程情况、"厕所革命"改造后满意度情况、"厕所革命"改造针对性问题和难点情况进行了对比分析,提出要进一步构建宣传机制、增加资金投入完善设施设备、建立长效维护管理体制及科技赋能绿色厕所的发展建议.
本刊讯《环境卫生工程》2022年度优秀论文、优秀审稿人评选结果于日 前揭晓.评选出卓越论文3篇、优秀论文7篇、最佳人气论文1篇以及《环境卫生工程》期刊最佳审稿人3名、优秀审稿人7名,名单如下.
随着现代工业的高速发展,危险废物污染已成为环境突出问题.为全面了解当前国内外危险废物相关研究的现状与方向,对Web of Science与中国知网数据库中危险废物研究领域相关文献进行汇总整理,使用文献计量学方法分析该领域近20年来的发展现状、前沿热点与发展趋势.结果显示,目前危险废物研究领域相关文献发表与科研合作规模呈现稳中有增的态势,国内外均对其表现出高度的重视.中国自2009年起在该领域发展提速,发文量与国际合作规模现已跃居世界首位.关键词等可视化分析结果表明,当前危险废物研究领域主要聚焦于政策标准制定、处置技术研发与污染物环境影响评价,其中吸附、固化/稳定化及协同处置等是该领域主要研发的处置技术;重金属、砷及二(英等污染物的迁移释放及浸出毒性等是该领域的研究热点.在循环经济发展模式下,有利于危险废物综合利用的生命周期评价开始取代以往片面单一的研究方法,实现危险废物减量化、无害化与资源化将成为今后危险废物研究的出发点与首要目标.
我国城镇污水厂普遍存在进水C/N失调的现象,这是制约污水反硝化脱氮的重要因素.外加碳源强化反硝化过程是克服C/N失调的重要措施,但存在成本高、二次污染等问题.有机废弃物中含有丰富的碳源物质,有望替代污水厂使用的化石碳源,这有利于垃圾减量化及资源化,同时也能降低污水处理成本.对近年来国内外利用有机废弃物制备碳源的研究进展进行了归纳,主要是餐厨垃圾和果蔬垃圾;对碳源化过程的关键影响因素进行总结,概述了pH、温度、有机负荷、酶、不同预处理技术对碳源化过程的影响,以及有机废弃物碳源化利用技术在市政污水、垃圾渗滤液、养殖废水及污泥领域的应用现状,并展望有机废弃物碳源化利用技术的未来发展方向.
针对城市生活垃圾焚烧发电厂主厂房建筑面积、混凝土配筋量、桩基优化、渗滤液原液回喷、主蒸汽参数选择、在线吹灰组合模式、厂用电率等7个关键设计要素,从降本增效的角度提出了中小型生活垃圾焚烧发电厂优化设计思路.通过多个典型案例的技术经济指标比对与分析,形成了500 t/d×1和500t/d×2规模的生活垃圾焚烧发电厂7个设计推荐应用模式或典型控制值.其中:主厂房面积宜控制在12 000～19 000m2,主厂房混凝土配筋量宜控制在160～195 kg/m3,通过合理的桩型选择和试桩优化可以节约25％以上桩基投资,渗滤液原液回喷单条焚烧线可降低渗滤液处理系统30 t/d设计规模,主蒸汽宜选用450 ℃、6.4 MPa的中温次高压参数,余热锅炉宜采取"水喷淋吹灰+蒸汽吹灰+激波吹灰"的在线吹灰组合模式,厂用电率宜控制在14％～18％.
通过文献调研、问卷调查以及成本测算的方法,对北京市生活垃圾分类政策的实施效果进行了评估,比较垃圾分类政策实施前后北京市生活垃圾收运处理情况,对北京市生活垃圾的管理现状及存在问题进行了剖析.结果表明:垃圾分类政策的实施促进了垃圾减量化和资源化,提升了居民环保意识;虽然现有生活垃圾处理设施能够匹配当下的处理需求,但随着垃圾分类工作的推进和垃圾处理设施的新建,焚烧企业将出现"吃不饱"的状况,因此需要对垃圾分类和设施建设进行利弊权衡,进一步优化布局并做合理规划.在此基础上,充分考虑北京市垃圾分类政策实施过程中面临的机遇与挑战,从提升分类质量、调整设施建设、创新分类模式、建立协调机制等多方面提出深入推进北京市生活垃圾分类的对策建议,为城市生活垃圾管理规划与政策制定提供了理论基础与现实依据.
以浓缩灰为研究对象,采用HC1为酸洗浸提剂,将重金属洗脱到酸洗液中,研究了3种重金属沉淀剂:片碱(NaOH)、30％NaOH溶液和Na2CO3粉末对酸洗液中Zn、Pb、Cu、Cd沉淀脱除效果的影响.结果表明:在pH为7～9时,3种重金属沉淀剂对4种重金属的沉淀脱除率均随pH增大呈增加趋势,且NaOH类沉淀剂对重金属的沉淀脱除效果远高于Na2CO3类沉淀剂;在pH＞9时,其脱除率增长趋势变缓或略有下降.其中,Na2CO3粉末、30％NaOH溶液、片碱(NaOH)分别在pH为9、10、10时,对4种重金属的综合脱除效率达到峰值,分别为97.95％、98.71％、99.41％.3种沉淀剂对重金属的脱除效果差别不大,但综合考虑成本、运输、储存及投料等工程应用价值及安全生产方面,采用片碱(NaOH)作为重金属沉淀剂,调节反应溶液pH为10时,对浓缩灰酸洗液中重金属的脱除效果最佳,最适于工程应用.
以长春市周边主要公路沿线的农田土壤为研究对象,开展环境风险研究,通过分析农田土壤的多环芳烃(Polycyclic Aromatic Hydrocarbons,PAHs)含量和种类,对PAHs的分布特征和来源进行分析,以期为长春地区治理PAHs污染提供参考.结果表明,PAHs总含量范围为0.85～45.86mg/kg,PAHs主要来源以生物质燃烧源为主,石油源与石油燃烧源同时存在.研究区农田土壤有50％的点位存在着一定程度的PAHs污染风险,需要引起关注.
为科学合理制订露天堆放废物危险特性鉴别采样方案,直观展示超鉴别标准限值废物空间分布范围,针对某大型废物堆放场地展开研究.首先,应用ArcGIS进行绘制堆放边界、创建网格、计算中心坐标、顺序编号等操作,制订废物采样方案;然后,应用EVS创建堆场地形和浸出毒性无机氟化物三维可视化模型,对比Kriging、IDW、NN和RBF 4种插值方法中无机氟化物超标空间范围和方量差异;最后,采用K折交叉验证评估插值精度.研究表明:应用ArcGIS制订采样方案可大幅简化现场工作量;应用EVS 4种插值方法构建的三维可视化模型存在差异,进一步证实了Kriging插值精度最高,较切实地反映出超标空间范围,并可据此估算超标方量.
目前,中国的城市生活垃圾产生量已占到全球垃圾产生量的13％,其处理处置已然成为我国建设"无废城市"、实现"碳达峰""碳中和"目标的关键.对标和梳理了国际通行的4种温室气体排放核算方法,分析了各方法应用于我国城市生活垃圾碳减排核算的适用性和不足.进而基于全生命周期评价方法,在调研分析国内外案例的基础上,总结提出了优化焚烧技术性能、高效利用填埋气、厌氧消化处理厨余垃圾、分类回收利用可回收物、建设生活垃圾处理产业园区等城市生活垃圾碳减排路径,并对每条路径的发展方向进行展望,旨在为城市生活垃圾处理行业在"十四五"期间实现全生命周期绿色、低碳发展提供理论支撑.
[基本情况] 本研究采用硬件+软件相结合的方式,自2017年开始针对垃圾分类投放准确率不高、人工督导难度大等问题,深入研发垃圾分类信息化技术平台系统、分类智能投放箱体和AI识别技术、垃圾分类信息化运营监管平台等关键技术,相关成果获得发明专利6项、实用新型专利13项.
[基本情况] 本研究团队创建了垃圾分类物元分析模型、投放方案灰色聚类比选模型及分类效果F-measure评价模型;基于城乡差别和农村地区生活垃圾产生源分布及性状特征,提出了农村生活垃圾"五类三段"分类模式,指出易腐垃圾就地/就近处理是农村垃圾分类的重点与关键;结合农村易腐垃圾就近处理需求,研发了引风式静态堆肥技术和重力翻板式间歇动态堆肥技术及装备,并在福建省明溪县胡坊镇和安徽省凤阳县小岗村进行了工程示范.
[基本情况] 本研究团队在全国各城市开展现场调研和问卷调查,调研对象包括政府主管部门、街道社区、第三方服务企业、公众等不同利益群体,了解垃圾分类工作实际开展过程中的问题和难点,针对性地提出生活垃圾分类的综合管理模式、城乡统筹模式、利益平衡模式、垃圾分类方式等,并应用于深圳、北京、海口、上饶、长沙、苏州等城市及福建省、陕西省的专项规划、专题研究及技术咨询.根据住房城乡建设部相关要求,对生活垃圾分类重点城市和整省统筹推进生活垃圾分类的情况进行摸底调研和阶段性成效总结,指导各省市落实生活垃圾分类目标和任务,并对项目研究成果进行闭环反馈和优化完善.
