Energy implications of mechanical and mechanical–biological treatment compared to direct waste-to-energy

Primary energy savings potential is used to compare five residual municipal solid waste treatment systems, including configurations with mechanical (MT) and mechanical–biological (MBT) pre-treatment, which produce waste-derived fuels (RDF and SRF), biogas and/or recover additional materials for recycling, alongside a system based on conventional mass burn waste-to-energy and ash treatment. To examine the magnitude of potential savings we consider two energy efficiency levels (state-of-the-art and best available technology), the inclusion/exclusion of heat recovery (CHP vs. PP) and three different background end-use energy production systems (coal condensing electricity and natural gas heat, Nordic electricity mix and natural gas heat, and coal CHP energy quality allocation).The systems achieved net primary energy savings in a range between 34 and 140 MJ_primary/100 MJ_{input waste}, in the different scenario settings. The energy footprint of transportation needs, pre-treatment and reprocessing of recyclable materials was 3–9.5%, 1–18% and 1–8% respectively, relative to total energy savings. Mass combustion WtE achieved the highest savings in scenarios with CHP production, nonetheless, MBT-based systems had similarly high performance if SRF streams were co-combusted with coal. When RDF and SRF was only used in dedicated WtE plants, MBT-based systems totalled lower savings due to inherent system losses and additional energy costs. In scenarios without heat recovery, the biodrying MBS-based system achieved the highest savings, on the condition of SRF co-combustion. As a sensitivity scenario, alternative utilisation of SRF in cement kilns was modelled. It supported similar or higher net savings for all pre-treatment systems compared to mass combustion WtE, except when WtE CHP was possible in the first two background energy scenarios. Recovery of plastics for recycling before energy recovery increased net energy savings in most scenario variations, over those of full stream combustion. Sensitivity to assumptions regarding virgin plastic substitution was tested and was found to mostly favour plastic recovery.     

卫生填埋场结构稳定性问题分析

卫生填埋是一项特殊的工程，可能产生结构稳定性问题。本文根据填埋工程的特点，从填埋工程与地质环境相互作用的角度，分析了卫生填埋场边坡、地基、填埋体、垃圾坝等的稳定性问题的产生原因、影响因素及其表现形式。填埋工程改变了填埋场原有的力系平衡，填埋体成分结构复杂、抗剪强度低、压缩变形大是填埋场结构稳定性问题产生的主要原因：参滤液和填埋气体的孔隙压力、渗滤液的渗透压力、填埋气体爆炸的冲击力、施工作业的人为营力是影响填埋场结构稳定性的主要作用力；抗滑稳定性、渗透稳定性和沉降是填埋场结构稳定性的主要表现形式。     

固相微萃取-便携式GC/MS快速测定水中痕量有机磷农药

采用固相微萃取-便携式气相色谱/质谱联用法（In situ SPME/GC-MS）分析地表水和废水中6种有机磷农药,通过优化测定条件,使6种有机磷农药在200 μg/L~500 μg/L范围内线性良好。方法检出限为033 μg/L～122 μg/L,低、高质量浓度标准溶液6次测定结果的RSD为68%~175%,加标回收率为849%~109%,与实验室方法的测定结果基本一致。     

用混凝——吸附法处理造漆漂油废水的研究

本文针对造漆漂油废水COD高(>10000mg／1)，含油量高(>4g／1)废水量小(1天数吨)的特点，提出了混凝-浮选-砂滤-活性性炭吸附的工艺流程。实验说明选择合适的混凝剂硫酸铝和优化投药量，混凝浮选后的出水COD可去除98％以上。经砂滤和活性炭吸附后，COD，含油量和悬浮物均可达到排放标准。本文还根据活性炭吸附穿透曲线，计算了Bohart-Adams关系式中的吸附容量No，流速常数K和活性炭柱临界厚度D。     

固体废物资源化大有可为

炼油污水场的三泥和重油催化卸下的废催化剂等固体废物作为一种资源综合利用，化害为利，实现了经济效益，环境效益，社会效益的统一。     

危险废物焚烧中污染防治的过程控制

危险废物焚烧污染防治的重点在烟气的处理上,一般情况下烟气处理的能力是固定不变的,但焚烧系统焚烧的危险废物是千差万别的,产生的烟气中污染物浓度也是变化很大的,如果不优化废料配给等系统,很难保证烟气经处理后能达标排放。因此危险废物焚烧中污染防治是一个系统工程,需要焚烧过程中各个环节优化控制。本文以一德国企业的危险废物焚烧设备为例,详细论述在编写焚烧日计划、焚烧系统、热能利用系统和烟气处理系统等各环节的污染防治的过程控制。