生态系统结构对太湖有机聚集体理化性质的影响

2007年1~12月对太湖4个不同生态类型湖区水体中有机聚集体(organic aggregates,OA)的丰度、有机质含量和营养盐(N、P)含量及其它水环境因子进行了同步监测.结果表明,①OA是太湖水体中营养盐的一个重要来源,其N、P含量分别占水体中TN、TP的16.5%及43.3%;②水体中OA的丰度与水体的富营养化程度密切相关,随着水体富营养化水平的提高和浮游植物生物量的增加,OA丰度及其中有机质的含量也呈现逐渐上升的趋势;③风浪扰动对太湖水体中OA的理化性质影响较大.OA作为营养盐的一个重要载体,可能是浅水湖泊营养盐循环中的一个关键点.     

水溶性有机质对土壤及底泥中汞吸附行为的影响

以重庆市2种耕作土(黄壤和中性紫色土)及鱼塘底泥为试验材料,分别添加提取自腐殖土的DOM(DOMh),提取自稻草的DOM(DOM)和提取自污泥堆肥的DOM(DOMa),研究DOM对土壤及底泥中Hg的吸附行为的影响.结果表明.DOM对土壤及底泥中汞的吸附行为均有一定的抑制作用,这种抑制作用与DOM种类和试验材料的性质有关.添加不同来源的DOM,对Hg的抑制作用具体表现为:DOMh>DOMr>DOMa;添加同一种DOM时,对Hg吸附的抑制作用表现为鱼塘底泥>紫色土>黄壤.     

超声处理对剩余污泥的粒径和溶出物的影响

为了有效地发挥微型动物摄食对剩余污泥的减量作用,研究了超声声能密度和超声时间对剩余污泥的粒径和溶出物(蛋白质、多糖、DNA、COD及BOD)溶出的影响.在脉冲比2:1和超声时间10min的条件下,声能密度为0.2W·mL-1时出现一个污泥粒径变化的转折点,当小于转折点时污泥粒径随声能密度增加明显下降,而当大于转折点时污泥粒径几乎不受声能密度影响.在脉冲比2:1和声能密度0.8W·mL-1的条件下,超声时间5min是个转折点.上清液中溶出物的浓度随超声波声能密度或超声时间的增加而增加,各溶出物指标之间存在显著的相关关系.溶出物指标中蛋白质指标可以较好地反映出污泥破解状态.为了得到既能使污泥粒径变小到微型动物可摄食的程度又能使污泥中溶出物的溶出量最少的效果,建议声能密度或超声时间取上述转折点为限值.个数平均粒径(Dn)和重量平均粒径(Dw)分别反映了污泥的几何粒径变化和溶出物的溶出状况,因此,在超声破解污泥-微型动物摄食污泥的污泥减量工艺中可通过Dn和Dw的并用来决定剩余污泥超声处理的工艺参数.     

Vertical and temporal distribution of nitrogen and phosphorus and relationship with their influencing factors in aquatic-terrestrial ecotone： a case study in Taihu Lake, China

Vertical and temporal distributions of N and P in soil solution in aquatic-terrestrial ecotone （ATE） of Taihu Lake were investigated, and the relations among N, P, ORP （oxidation reduction potential）, TOC, root system biomass and microorganism were studied. As a whole, significant declines in TN, NO3^--N, DON （dissolved organic nitrogen） and TP concentration in soil solution have occurred with increase of the depth, and reached their minima at 60 cm depth, except for NH4^＋-N, which increased with depth. The concentration of TP increased gradually from spring to winter in the topsoil, the maximum 0.08 mg/L presented in the winter while the minimum 0.03 mg/L in spring. In the deeper layer, the concentration value of TP fluctuated little. As for the NO3^--N, its seasonal variation was significant at 20 cm depth, its concentration increased gradually from spring to autumn, and decreased markedly in winter. Vertical and temporal distribution of DON is contrary to that of NO3^--N. The results also show that the variation of N and P in the percolate between adjacent layers is obviously different. The vertical variation ofTN, TP, NO3^--N, NH4^＋-N and DON is significant, of which the variation coefficient of NO3^--N along the depth reaches 100.23%, the highest; while the variation coefficient of DON is 41.14%, the smallest. The results of correlation analysis show that the concentration of nitrogen and phosphorus correlate significantly with TOC, ORP, root biomass and counts of nitrifying bacteria. Most nutrients altered much from 20 to 40 cm along the depth. However, DON changed more between 60 and 80 cm. Results show that soil of 0-60 cm depth is active rhizoplane, with strong capability to remove the nitrogen and phosphorus in ATE. It may suggest that there exists the optimum ecological efficiency in the depth of above 60 cm in reed wetland. This will be very significant for ecological restoration and reestablishment.     

滇池福保湾沉积物不同形态磷的垂向分布

应用SMT连续提取法分析滇池福保湾柱状沉积物的磷(P)形态,探讨P形态的垂向分布特征.沉积物中总磷 (TP)含量高,最高达4　200 mg/kg, 无机磷 (IP)是TP的主要部分,占TP的52%～91%, 铁/铝结合态磷 (Fe/Al-P)是IP的主要部分,占IP的55%～94%.同一湖区不同采样点的沉积物P形态的垂向变化不同,湖湾北端近河口处和南端远离河口处的沉积物中Fe/Al-P, IP, 有机磷 (OP)和TP含量随深度增加而增加,6～11 cm 层的含量最高,这与近年来入湖河流污染负荷削减和河堤阻隔导致P入湖量减少有关.河口处沉积物的钙结合态磷 (Ca-P)含量随深度增加而增加,最南端沉积物的Ca-P含量随深度增加而减少.离河口较远的沉积物中,Fe/Al-P, IP, OP,TP和Ca-P均随深度增加而减少.各点沉积物P形态的变化受该点人类活动带来的入湖污染物量的影响较大,距河口最远处的沉积物中P形态随深度变化不如其他点明显.      

Partitioning of water soluble organic carbon in three sediment size fractions： Effect of the humic substances

Water soluble organic carbon (WSOC) in sediments plays an important role in transference and transformation of aquatic pollutants. This article investigated the inherent mechanisms of how sediemnt grain size affect the partitioning coeffcient (k) of WSOC. Influences of NaOH extracted humic substances were particularly focused on. Sediments were sampled from two cross-sections of the middle Yellow River and sieved into three size fractions (< 63 μm, 63-100 μm, and 100--300 μm). The total concentration of WSOC in sediments (CWSOC) and k were estimated using multiple water-sediment ratio experiments. Results show that CWSOC ranges from 0.012 to 0.022 mg/g, while k ranges from 0.8 to 3.9 L/kg. Correlations between the spectrum characteristics of NaOH extracted humic substances and k were analyzed. Strong positive correlations are determined between k and the aromaticity indicators of NaOH extracted humic substances in different sediment size fractions. Comparing with finer fractions (< 63 μm), k is higher in larger size fractions (63--100 and 100--300 μm) related to higher aromaticity degree of NaOH extracted humic substances mostly. While negative relationship between k and the area ratio of fourier transform infrared spectroscopy (FT-IR) at 3400 and 1430 cm-1 implied that the lowest k was related to the highest concentration of the acidic humic groups in particles < 63 μm. WSOC in finer fractions (< 63 μm) is likely to enter into pore water, which may further accelerate the transportation of aquatic contaminants from sediment to water.     

苯噻草胺在土壤中的吸附与解吸行为研究

采用批量平衡实验方法,研究了除草剂苯噻草胺在5种不同性质土壤中的吸附与解吸行为,并探讨了土壤有机质及溶液pH值对吸附的影响.结果表明,线性方程与Freundlich方程均能较好地拟合苯噻草胺在土壤中的吸附等温线.计算得到苯噻草胺在5种土壤中的碳标化分配系数K_oc在849.5～1?818.8 L·kg^-1之间,说明土壤对苯噻草胺有较强的吸附能力.苯噻草胺在土壤中的分配系数K_d、Freundlich常数K_f以及K_f(1/n)与土壤有机质含量均呈显著正相关.通过过氧化氢去除有机质后,土壤对苯噻草胺的吸附大大降低,说明土壤有机质是影响苯噻草胺在土壤中吸附的主要因素.对于同种土壤而言,苯噻草胺的吸附量随pH值的增大而减小.解吸实验表明,苯噻草胺在土壤中的解吸过程具有一定的滞后性,推测其在土壤中的迁移能力较差.     

南四湖微山湖区沉积物磷形态分布特征

为了解南四湖污染底泥磷形态分布规律,对南四湖微山湖区0～25 cm沉积物分层进行了磷形态连续提取.结果表明,湖区沉积物中Ex-P、Al-P、Fe-P、Oc-P、Ca-P、De-P和Org-P平均含量分别为5.62、 4.08、 12.25、 13.34、 116.67、 232.36和396.79 mg/kg,不同形态磷含量次序为：Al-P＜Ex-P＜Fe-P＜Oc-P＜Ca-P＜De-P＜Org-P.沉积物中各形态磷含量在垂直方向上呈现明显的规律性,易交换态磷（Ex-P）、铁结合态磷（Fe-P）、闭蓄态磷（Oc-P）、有机磷（Org-P）含量随深度增加而逐渐降低,而铝结合态磷（Al-P）、钙结合态磷（Ca-P）、碎屑磷（De-P）含量则呈逐渐增加趋势.Sum1（Ex-P、Al-P、Fe-P之和）与上覆水PO^3-₄浓度呈显著正相关,其中Fe-P与水体磷酸盐含量关系相对比较密切,其相关系数高达0.72.沉积物磷形态在空间分布上,Oc-P、Ca-P、De-P 等惰性磷的差异性小于Ex-P、Al-P、Fe-P等潜在活性磷,Org-P介于二者之间.     

溶解性有机氮乙酰胺氯化生成饮用水THMs的影响因素研究

氯化消毒可以有效杀灭细菌,但同时会产生危害人体健康的消毒副产物(DBPs).溶解性有机氮(DON)是DBPs的重要前体物,为考察DON对THMs的影响,首次选取乙酰胺(AcAm)作为前体物DON的代表物质,采用Plackett-Burman和Box-Behnken方法设计试验,考察了AcAm初始浓度、加氯量、pH、温度、溴离子浓度和反应时间等因素对三卤甲烷(THMs)生成的影响.结果表明,在AcAm生成THMs的过程中,AcAm初始浓度、pH和反应温度3个因素的影响程度较小,溴离子、有效氯和反应时间3因素的影响较大,其中溴离子的影响最为显著.溴离子浓度一定时,改变有效氯的含量,生成的THMs总量变化不大,溴离子对THMs的生成有一定的催化作用,控制溴离子的浓度是减少AcAm生成THMs的有效措施.在有效氯为8.77 mg/Ｌ、溴离子为0.77 mg/Ｌ及接触时间为6.20 h的条件下,THMs存在最大生成量为45.82 μg/L.随着反应时间的推移,溴分配系数n呈上升趋势,控制消毒反应时间,是减少THMs致癌风险的有效方法.同时探讨了AcAm生成THMs的反应路径,表述了溴离子的催化作用机制.     

餐厨垃圾和剩余污泥厌氧混合发酵过程的动态膜强化特性研究

比较了厌氧动态膜生物反应器（DMBR）与完全混合式反应器（CSTR）在处理餐厨垃圾（FW）和剩余污泥（WAS）时的发酵产气过程,验证了高负荷餐厨垃圾和剩余污泥混合发酵时DMBR系统运行的稳定性,考察了动态膜（DM）基材孔径（300目、200目和100目）对DMBR运行性能及其固液分离效果的影响.结果表明：一体式DMBR能够强化餐厨垃圾和剩余污泥混合发酵的高负荷稳定运行,DMBR过膜滤液中平均总挥发性脂肪酸（TVFA）为86.1 mg·L^-1,低于CSTR排泥中TVFA的浓度（527.3 mg·L^-1）.当动态膜基材孔径为300目时,DMBR过膜滤液中总有机物（TCOD）为（1.6±1.1）g·L^-1,相应的固液分离效果优于200目（（3.2±1.9）g·L^-1）和100目（（32.0±1.3）g·L^-1）动态膜基材,即当动态膜基材孔径为100目时,DMBR过膜滤液中TCOD比300目动态膜基材高6.7倍.与200目动态膜基材孔径相比,300目动态膜基材相应的跨膜压差增长缓慢,反洗频率和运行能耗均较低,而100目动态膜基材孔径过大,固液分离效果较低.因此,在高负荷餐厨垃圾和剩余污泥混合发酵系统中,选用300目动态膜基材形成的动态膜过滤效果最优.此外,本文还对比分析了有机废物和废水处理领域中较优的动态膜基材孔径及DMBR的应用情况,为拓展DMBR在有机物处理领域的应用提供依据.