利用含铬废水和含铅废水制备铬黄

利用净化后的含铬废水和含铅废水制备铬黄.采用沉淀法对废水进行净化预处理,最佳工艺条件:100mL含铬废水中加入20 g Na_2CO_3,及10 mL H_2O_2,用NaOH调节含铬废水pH为10.00;用NaOH调节含铅废水pH为2.65.将净化后的10 mL含铬废水和25 mL含铅废水混合,在55-60℃条件下反应10 min,合成的铬黄达到GB/T 3184-2008<铬酸铅颜料和钼铬酸铅颜料>的质量标准.经重金属吸附剂处理Pb~(2+)后铬黄合成滤液中的Cr~(6+)和Pb~(2+)质量浓度均达到GB8978-1996<污水综合排放标准>的指标.     

改性高岭土处理含酸性媒介染料的印染废水

用十六烷基三甲基溴化铵(CTMAB)改性的高岭土处理以水溶性酸性媒介染料为主的印染废水.实验结果表明,当CTMAB-高岭土加入量为0.6 g/L、用石灰乳控制废水pH为9.5～10.0、聚丙烯酰胺的加入量为2.0 mg/L时,废水的处理效果最佳,废水色度和COD去除率分别达到98.0%和92.0%以上,出水色度和COD达到了GB4287-92<纺织染整工业水污染物排放标准>一级排放标准.     

Liquefaction process for a hydrothermally treated waste mixture containing plastics

Most landfilled plastic waste is a mixture or is in the form of composites with incombustible wastes such as glass, metals, and ceramics. After hydrothermal treatment, including a steam-explosion process, the separation of mixed waste (MW) into organic and inorganic substances becomes easy. However, the effect of hydrothermal pretreatment on the subsequent liquefaction of organic substances from MW is not obvious. In this study, the effects on the liquefaction of polystyrene and high-density polyethylene are discussed. Moreover, optimum conditions for the liquefaction of organic substances from hydrothermally treated MW are identified. By means of this hydrothermal pretreatment, including the steam-explosion process, polystyrene and high-density polyethylene can be significantly converted to oil by liquefaction at 300°–400°C. In comparison with liquefaction of hydrothermally pretreated mixed waste (HMW) at 300°–400°C with a batch type reactor, the yield of oil increases significantly on liquefaction using a semi-batch type reactor. It is considered that the radical chain and termination reactions among the radicals from HMW were inhibited in the semi-batch type reactor. On liquefaction of HMW in a semi-batch reactor, the conversion of HMW to oil was enhanced on increasing the liquefaction temperature to 350°C and the holding time to 60 min. Chemical Feedstock Recycling & Other Innovative Recycling Techniques 6     

Dechlorination of polyvinyl chloride in NaOH/ethylene glycol solution by microwave heating

This study investigated the dehydrochlorination of flexible polyvinyl chloride (PVC) containing 59.2% PVC, 29.7% dioctyl phthalate (DOP), and approximately 12% stabilizers. Flexible PVC was treated with NaOH/ethylene glycol (NaOH/EG) solutions at NaOH concentrations in the range 0.5–4 mol/l and was heated in a microwave heater at a temperature between 100° and 160°C for 0–30 min. All chlorides were completely eliminated by internal heating at 160°C using microwaves for 10 min in a 1 mol/l NaOH/EG solution, and the residue was made up of hydrocarbons. The weight loss rate reached a maximum of 74.7% at a temperature of 160°C. It was discovered that the use of microwaves significantly shortened the reaction time compared to using conventional electric heaters or other external heating systems and also allowed the use of lower concentrations of NaOH. Chemical Feedstock Recycling & Other Innovative Recycling Techniques 6     

铁碳微电解法在废水处理中的研究进展及应用现状

介绍了铁碳微电解法处理废水的作用机理,概述了近10年来国内外利用铁碳微电解法及其组合工艺对印染、造纸、焦化、炸药、制药等废水处理方面的研究进展及实际的应用状况.提出了铁碳微电解法在运行过程中存在的几个问题,并对今后研究工作的大体方向做了初步的探讨.     

1.5t、3t电弧炉烟尘治理

针对1.5 t、3 t电弧炉在烟尘治理时场地狭小的特点,采用可折叠式收尘罩与低压长袋脉冲袋式除尘器技术进行治理.测试表明,系统运行可靠,烟尘治理效果良好,工厂车间环境取得显著改善,岗位粉尘浓度、烟尘排放浓度均达到国家规定的标准.     

辽河稠油热采现场硫化氢的防范与治理建议

硫化氢是一种剧毒和较强腐蚀性的气体,近年来在辽河油田一些地区相继出现,特别是稠油热采区块出现了较高浓度的硫化氢。硫化氢的存在已经威胁到油田的安全生产,并成为油气勘探开发过程中必须解决的问题。本文对辽河油气稠油热现场硫化氢的预防与治理提出了一些建议。     

Evaluating soundscape intentions in landscape architecture: a study of competition entries for a new cemetery in Järva,Stockholm

While soundscape is increasingly acknowledged within landscape planning and design discourse, there is little research that clarifies how soundscapes are actually dealt with in landscape architecture practice – partly owing to methodological insufficiencies. This paper, therefore, describes a model for evaluating soundscape treatment in landscape design proposals, focusing on three key aspects. With the dual aim of testing the model, and learning more about how soundscape is approached in practice, the paper spotlights a major design competition for a new cemetery in Sweden. The model proved fruitful and easy to apply. It showed that only limited attention was paid to soundscape in the competition as a whole, and was a useful means of pinpointing proposals where soundscape was fully considered as a design feature; one competition entry that did so is described in the paper. Discussions cover design practice, trends in the competition and model application.     

Swine wastewater treatment in a two stage sequencing batch reactor using real‐time control

Abstract

A laboratory scale two‐stage sequencing batch reactor (TSSBR) was used to study the effectiveness of pH as a real‐time control parameter in swine wastewater treatment. A Ringlace media was inserted into the A/O (Anoxic/Oxic) reactor for bacteria immobilization. The TSSBR was subjected to three levels of organic loading. The pH and ORP (Oxidation Reduction Potential) patterns obtained were consistent with distinct features, enabling the real‐time control strategy to effectively set a flexible aeration time pending on influent concentration, hence resulting in flexible cycle time and HRT (Hydraulic Retention Time) for the system. The real‐time process ensured a removal efficiency of over 99% and 95%, respectively, for ammonia and TOC (Total Organic Carbon). For NO₃ ^‐‐N and PO₄ ^‐3, the run with influent TOC = 4,000 mg/L yielded the most efficient removal of 61% and 95%, respectively. Test results suggest that pH can be a viable tool for on‐line real‐time control of a biological treatment process.     

Treatment of wastewater from red and tropical fruit wine production by zeolite anaerobic fluidized bed reactor

A study of the anaerobic treatment of wastewaters derived from red (RWWW) and tropical fruit wine (TFWWW) production was carried out in four laboratory-scale fluidized bed reactors with natural zeolite as bacterial support. These reactors operated at mesophilic temperature (35°C). Reactors R1 and R2 contained Chilean natural zeolite, while reactors R3 and R4 used Cuban natural zeolite as microorganism support. In addition, reactors R1 and R3 processed RWWW, while reactors R2 and R4 used TFWWW as substrate. The biomass concentration attached to zeolites in the four reactors studied was found to be in the range of 44–46 g volatile solids (VS)/L after 90 days of operation time. Both types of zeolites can be used indistinctly in the fluidized bed reactors achieving more than 80%–86% chemical oxygen demand (COD) removals for organic loading rates (OLR) of up to at least 20 g COD/L d. pH values remained within the optimal range for anaerobic microorganisms for OLR values of up to 20 and 22 g COD/L d for RWWW and TFWWW, respectively. Toxicity and inhibition levels were observed at an OLR of 20 g COD/L d in reactors R1 and R3 while processing RWWW, whereas the aforementioned inhibitory phenomena were not observed at an OLR of 24 g COD/L d in R2 and R4, treating TFWWW as a consequence of the lower phenolic compound content present in this substrate. The volatile fatty acid (VFA) levels were always lower in reactors processing TFWWW (R2 and R4) and these values (< 400 mg/L, as acetic acid) were lower than the suggested limits for digester failure. The specific methanogenic activity (SMA) was twice as high in reactors R2 and R4 than in R1 and R3 after 120 days of operation when all reactors operated at an OLR of 20 g COD/L d.