基于改性凹凸棒土的强化混凝处理高藻低浊原水工艺

针对水厂低浊高藻水的处理难题,研究了改性凹凸棒土(改性凹土)联合聚合氯化铝(PAC)强化混凝的除藻除浊效果。设计实验原水条件为叶绿素a(chl-a)浓度为98.58~110.35μg/L,浊度(5.6±0.5)NTU。考察了PAC和改性凹土的复配投加量、混凝沉淀时间、pH、投加顺序、搅拌速率等工艺参数对Chl-a和浊度耦合去除效果的影响。结果表明,"PAC+改性凹土"对Chl-a和浊度的去除效果明显优于单投PAC的效果。当PAC投药量12 mg/L,改性凹土投药量10 mg/L,沉淀时间20 min时,对Chl-a和浊度的去除率可分别达到92.5%和89.2%,可至少减少40%的PAC投量,且形成的矾花密实,沉降速度快,去除效率高。最适pH范围为7~8。投加顺序应为先投加改性凹土,混合搅拌转数宜慢速,可控制为50 r/min。     

剩余污泥的水解与氮磷回收

传统污水好氧生物处理过程中产生大量剩余污泥,这些污泥有机质中富含大量的氮磷元素。随着剩余污泥的消化并最终处置,大量的氮磷资源被白白浪费。在污泥消化过程中有机态氮磷可以在水解类细菌的水解作用下最终以氨氮和磷酸盐的形式溶出。当水解液中氨氮和磷酸盐达到一定浓度时,投加镁盐并调节pH,生成鸟粪石沉淀。鸟粪石作为一种缓释肥具有良好的经济效益。从资源回收的角度看,对剩余污泥水解酸化阶段研究有利于实现剩余污泥中氮磷资源的有效回收。     

绥棱县城镇环境噪声变化趋势的研究

绥棱县环境监测站自1987年以来,每年对城镇环境噪声进行一次监测。经过多年监测,获得监测数据30多万个,通过对比得出：工业噪声源的影响在逐年变小,工业声源影响构成百分比由20年前的38%降至现在的20%,但局部地区对附近居民的影响依旧存在;随着城镇建设速度的加快,建筑施工噪声源的影响在逐年加大,施工声源构成百分比由20年前的2%增加到12%;随着交通运输业的发展,车流量的逐年增多,道路交通噪声污染在逐年加重,超标路段由20年前的13.7%上升到现在的32.3%;目前处于超标环境中的面积率和人口率分别为51.9%和69.2%,白天居民生活居住区和混合区噪声污染较重,夜间有三分之一居住混合区污染还很严重。     

苏北农房易损性分析研究

分析研究农村房屋易损性是防震减灾工作中必不可少的一部分.本文通过对苏北地区自然村民房的随机调查,分析其存在的问题,对其做出易损性的分析研究.苏北地区农房抗震性能总体水平较低.随着农村经济的发展和提高,应加强农村民居防震减灾工作指导,提高农村民居抗震能力.     

曝气生物滤池处理效果影响因素试验研究

曝气生物滤池具有占地面积小、处理效率高等特点而成为分散型污水处理技术的优先选择,为了进一步优化该工艺的运行控制,通过试验研究了有机负荷、水力停留时间、气水比等因素对曝气生物滤池处理效能的影响,结果表明曝气生物滤池对有机负荷、水力停留时间、气水比变化具有良好的适应能力。在温度为20℃～25℃时,COD负荷在1-4．5kg／m^3·d之间、气水比在3：1～10：1之间、水力停留时间在30min-60min之间时,COD去除效果良好,平均去除率可达85％。COD负荷、停留时间和气水比对硝化反应影响显著,增加COD负荷对反应器的硝化能力有明显的抑制作用,反应器需要充分硝化时的进水有机负荷应控制在1．5kgCOD／m^3·d以内较为合适。停留时间在30min-60min、气水比在3：1～10：1范围内变化时,NH4^＋-N去除率增加显著。     

扎龙保护区野生丹顶鹤种群现状及保护对策

对多年扎龙湿地野生丹顶鹤的种群数量及繁殖情况的调查数据作了详细统计,阐述了种群数量和繁殖巢数变化的原因,分析了丹顶鹤生存环境面临的威胁因素,并提出了相应的保护措施.     

流动注射在线离子交换富集-原子荧光光谱法测定环境水样中痕量汞

提出了一种流动注射在线离子交换富集一氢化物发生原子荧光光谱法测定水样中总汞的分析方法。设计了双柱并联富集，串联洗脱的在线离子交换流路及操作程序，优化了各项化学条件及流路参数。方法操作简便快速，灵敏度高，干扰少。富集倍数达25倍以上，采样频率为30次／h，回收率达90％－105％。应用于环境水样中痕量汞的测定，获得了满意的结果。     

广东省主要土类的三卤甲烷生成潜能(THMFP)

通过振荡浸出实验,测定了广东省几种主要土类的三卤甲烷生成潜能(THMFP),比较了土壤浸提液中溶解态(可过滤态)有机物与悬浮态(不可过滤态)有机物在形成三卤甲烷(THMs)中的作用,并对影响土壤THMFP的各种因素进行讨论结果表明:①各主要土类表层土中,未过滤浸提液的整体THMFP(b-THMFP)含量范围为:0.7～36.8μg/g土,中值为10.6μg/g土;过滤浸提液的THMFP(指可溶性有机物的THMFP,即d-THMFP)含量范围为:0.5～21.2μg/g土,中值为3.9μg/g土;其中,19号石灰土的b-THMFP和d-THMFP最高,20号紫色土的b-THMFP最低,5号赤红壤的d-THMFP最低.②总体上,悬浮态有机物对THMs生成量有较大的正贡献.③影响土壤THMFP的因素主要是有机质含量、各种氧化物含量、土壤发生层次、植被等.     

重庆三峡库区主要生态环境问题与对策

三峡水电站建成后，制约重庆经济可持续发展的关系是生态环境问题，包括三峡库区的水体污染，水土流失与泥沙问题，灾害性地质环境问题，建议建立三峡库区生态环境委员会，实行在市长领导下的环境保护行政领导责任制依法治库，加强生态环境意识教育，建立生态环境保护基金等。     

Effects of an iron-silicon material,a synthetic zeolite and an alkaline clay on vegetable uptake of As and Cd from a polluted agricultural soil and proposed remediation mechanisms

Economic and highly effective methods of in situ remediation of Cd and As polluted farmland in mining areas are urgently needed. Pot experiments with Brassica chinensis L. were carried out to determine the effects of three soil amendments [a novel iron-silicon material (ISM), a synthetic zeolite (SZ) and an alkaline clay (AC)] on vegetable uptake of As and Cd. SEM–EDS and XRD analyses were used to investigate the remediation mechanisms involved. Amendment with ISM significantly reduced the concentrations of As and Cd in edible parts of B. chinensis (by 84–94 % and 38–87 %, respectively), to levels that met food safety regulations and was much lower than those achieved by SZ and AC. ISM also significantly increased fresh biomass by 169–1412 % and 436–731 % in two consecutive growing seasons, while SZ and AC did not significantly affect vegetable growth. Correlation analysis suggested that it was the mitigating effects of ISM on soil acidity and on As and Cd toxicity, rather than nutrient amelioration, that contributed to the improvement in plant growth. SEM–EDS analysis showed that ISM contained far more Ca, Fe and Mn than did SZ or AC, and XRD analysis showed that in the ISM these elements were primarily in the form of silicates, oxides and phosphates that had high capacities for chemisorption of metal(loid)s. After incubation with solutions containing 800 mg L^?1 AsO₄ ^2? or Cd²⁺, ISM bound distinctly higher levels of As (6.18 % in relative mass percent by EDS analysis) and Cd (7.21 % in relative mass percent by EDS analysis) compared to SZ and AC. XRD analysis also showed that ISM facilitated the precipitation of Cd²⁺ as silicates, phosphates and hydroxides, and that arsenate combined with Fe, Al, Ca and Mg to form insoluble arsenate compounds. These precipitation mechanisms were much more active in ISM than in SZ or AC. Due to the greater pH elevation caused by the abundant calcium silicate, chemisorption and precipitation mechanisms in ISM treatments could be further enhanced. That heavy metal(loid)s fixation mechanisms of ISM ensure the remediation more irreversible and more resilient to environmental changes. With appropriate application rate and proper nutrients supplement, the readily available and economic ISM is a very promising amendment for safe crop production on multi-metal(loids) polluted soils.