基于干湿分类优化的城市生活垃圾收运处理系统研究

为解决"垃圾围城"困境,在充分考量我国城市生活垃圾特点、居民生活垃圾分类能力以及垃圾处理可行方案的前提下,提出以干湿分类为基础,并对干垃圾进行二次分类的城市生活垃圾分类体系。基于此分类体系,对既有生活垃圾收运处理系统的优化调整进行了探讨,提出优化调整原则。最后,以郑州市为例,给出了城市生活垃圾收运处理系统优化调整的具体方案,并证明了新的城市生活垃圾分类体系,以及对城市生活垃圾收运处理系统的优化调整,在提高垃圾资源化率和减少填埋量方面的有效性。     

Biodecoloration of Reactive Black 5 by the methylotrophic yeast Candida boidinii MM 4035

Azo dyes are extensively used in textile dyeing and other industries. Effluents of dying industries are specially colored and could cause severe damage to the environment. The anaerobic treatment of textile dying effluents is nowadays the preferred option, but it could generate carcinogenic aromatic amines. Recently, yeasts have become a promising alternative, combining unicellular growth with oxidative mechanisms. This work reports the characterization of the first methylotrophic yeast with dye decolorizing ability, Candida boidinii MM 4035 and some insights into its decoloration mechanism. The analysis of two selected media revealed a possible two stages mechanism of Reactive Black 5 decoloration. In glucose poor media, decoloration is incomplete and only the first stage proceeds, leading to the accumulation of a purple compound. In media with higher glucose concentrations, the yeast is able to decolorize totally an initial concentration of 200 mg/L. The entire process is co-metabolic, being largely dependent on glucose concentration but being able to proceed with several nitrogen sources. Manganese dependent peroxidase but not laccase activity could be detected during decoloration. Aromatic amines do not accumulate in culture media, supporting an oxidative decoloration mechanism of unknown ecophysiological relevance.     

Aeration optimization through operation at low dissolved oxygen concentrations: Evaluation of oxygen mass transfer dynamics in different activated sludge systems

In wastewater treatment plants(WWTPs)using the activated sludge process,two methods are widely used to improve aeration efficiency — use of high-efficiency aeration devices and optimizing the aeration control strategy. Aeration efficiency is closely linked to sludge characteristics(such as concentrations of mixed liquor suspended solids(MLSS)and microbial communities)and operating conditions(such as air flow rate and operational dissolved oxygen(DO)concentrations). Moreover,operational DO is closely linked to effluent quality. This study,which is in reference to WWTP discharge class A Chinese standard effluent criteria,determined the growth kinetics parameters of nitrifiers at different DO levels in small-scale tests. Results showed that the activated sludge system could meet effluent criteria when DO was as low as 0.3 mg/L,and that nitrifier communities cultivated under low DO conditions had higher oxygen affinity than those cultivated under high DO conditions,as indicated by the oxygen half-saturation constant and nitrification ability. Based on nitrifier growth kinetics and on the oxygen mass transfer dynamic model(determined using different air flow rate(Q′_(air))and mixed liquor volatile suspended solids(MLVSS)values),theoretical analysis indicated limited potential for energy saving by improving aeration diffuser performance when the activated sludge system had low oxygen consumption; however,operating at low DO and low MLVSS could significantly reduce energy consumption. Finally,a control strategy coupling sludge retention time and MLVSS to minimize the DO level was discussed,which is critical to appropriate setting of the oxygen point and to the operation of low DO treatment technology.     

Development of a method for comprehensive water quality forecasting and its application in Miyun reservoir of Beijing, China

Water quality forecasting is an essential part of water resource management. Spatiotemporal variations of water quality and their inherent constraints make it very complex. This study explored a data-based method for short-term water quality forecasting. Prediction of water quality indicators including dissolved oxygen, chemical oxygen demand by KMnO₄ and ammonia nitrogen using support vector machine was taken as inputs of the particle swarm algorithm based optimal wavelet neural network to forecast the whole status index of water quality. Gubeikou monitoring section of Miyun reservoir in Beijing, China was taken as the study case to examine effectiveness of this approach. The experiment results also revealed that the proposed model has advantages of stability and time reduction in comparison with other data-driven models including traditional BP neural network model, wavelet neural network model and Gradient Boosting Decision Tree model. It can be used as an effective approach to perform short-term comprehensive water quality prediction.     

以环境保护为基础的城市公园生态设计研究

从环境保护视野对城市公园景观优化设计进行研究,以环境保护为基础,探讨城市公园景观优化设计中应用环境保护的原则,以太原公园为例,介绍其景观优化设计方式,包括改善城市公园湖滨游步道的林荫绿化情况,增建亲水空间,优化座椅、休闲亭和餐饮设施,改善水景别墅前绿化景观,提升公园整体植物景观层次感,规划城市公园水生植物景观.总结出城市公园景观优化设计的策略主要为:设计湖滨亲水设施、营造水上景观、配置城市公园植物景观、设置沿岸的水景.     

耦合MOP与GeoSOS-FLUS模型的县级土地利用结构与布局复合优化

在自然资源整合不断加强,土地利用结构日趋复杂的形势下,采用单一土地利用结构优化方式难以有效满足区域土地利用合理规划的需求。综合考虑生态文明、乡村振兴、城乡融合等土地可持续利用目标,构建土地利用结构优化与布局优化的集成体系,对提升规划适用性具有积极作用。选取常州市金坛区为研究区,以经济效益与生态效益为优化目标,设置自然演变、经济优先和生态优先三种发展情景,在通过MOP(多目标规划)模型进行土地利用结构优化的基础上,利用GeoSOS-FLUS模型实现土地利用布局优化。结果表明:通过集成MOP和GeoSOS-FLUS模型,采用"结构+约束+布局+准则"研究模式探索县域单元下的土地利用结构布局优化,对调整土地利用结构,优化土地利用空间布局有一定帮助。从案例分析结果看,城镇工矿用地数量在自然演变和经济效益优先情景下分别增加了39%和95%;林地在生态效益优先情景下增加了40%;农村居民点在三种情景下分别减少33%、66%和66%。在三种发展情景下,空间格局都将面临城镇空间与生态空间两级分化的现象,后期区域发展中应加强城乡土地利用与生态保护协调发展,促进空间布局均衡化。     

管棚预支护条件下隧道开挖面稳定的可靠度分析

为考虑土体参数的变异性对隧道开挖面稳定性的影响,基于可靠度理论,采用三维弹塑性有限元数值模拟方法,计算管棚预支护条件下隧道开挖面极限支护力;以不同工况下地层参数及其极限支护压力比作为样本,待BP神经网络训练完毕后,即可预测大量给定地层参数工况下的开挖面极限支护压力比,对其进行统计,得到概率分布特征;在理论分析的基础上,结合工程实际,建立了管棚预支护条件下隧道开挖面稳定的极限状态方程,运用粒子群优化算法,对其进行可靠度分析。研究结果表明:采用管棚预支护的隧道,开挖面支护压力存在极限值,达到该值后,增加较小幅度的支护力,就能较大程度地提高隧道开挖面稳定的可靠度。     

基于回归分析的群集疏散时间模型优化研究

为提高国际上通用的疏散时间模型(简称经验模型)的仿真度,将人员的属性因素(自然属性和社会属性)影响纳入时间模型,采用回归分析方法,以某高校大型大学生艺术中心疏散案例为研究基础,通过调查采样建立185组数据的实测样本。结合影响人员疏散行为和疏散时间相关因素,运用统计软件SPSS17.0对样本进行回归分析,建立疏散时间回归模型。以回归模型为基础,将个体属性综合为群集属性,求取修正系数并对经验模型进行修正、检验。结果表明:利用回归分析和修正系数对疏散时间经验模型进行修正,可有效弥补经验模型缺乏考虑群集属性影响的弱点,提高经验模型的仿真度和应用价值。     

油气集输及处理节能减排的实践与探索

通过分析某作业区节能减排的现状、潜力及存在问题,结合典型实例,探讨了油田节能减排的途径和主要方法:应建立和完善各项节能减排制度,在推进能源节约、推行污染减排、加强资源综合利用等方面,实现全方位立体化节能减排。同时,应制定中长期工作规划,淘汰高能耗设备、应用新技术、加大监督检查力度等措施以实现油田企业可持续发展。