营养物质对污泥沉降性能的影响及污泥膨胀的控制

采用序批式活性污泥工艺(SBR)处理啤酒废水,研究了N、P营养物质的不同缺乏程度对污泥沉降性能的影响,同时考察了污泥絮体性状和微生物的变化.结果表明,原水BOD₅/N/P为100/5/1、100/5/0.8和100/4/0.8时,污泥沉降性能良好,没有发生膨胀;BOD₅/N/P为100/0.94/0.31、100/2/0.4、100/3/0.6时发生丝状菌污泥膨胀;BOD₅/N/P为100/0.94/1、100/5/0.31、100/5/0.4、100/5/0.6时发生非丝状菌污泥膨胀.缺乏营养物质引起的污泥膨胀,多数情况下补充足够的营养物质后,膨胀可得到控制.提高有机负荷有助于改善污泥的沉降性能.进水N、P营养物质同时缺乏时,可形成直径为2mm～6mm的颗粒污泥.     

用土壤生物和养分指标表征土壤肥力的可持续性

运用土壤生物和养分指标讨论了不同农田土壤肥力可持续性指数。结果表明, 不同施肥处理对土壤肥力可持续性指数有很大影响。有机肥明显提高土壤碳、氮和生物管理指数。单施化肥促进土壤磷、钾管理指数的上升。厩肥比绿肥更有利于提高土壤肥力可持续性指数。与参比土壤相比, 化肥处理的土壤肥力可持续性指数平均每年都增长, 红壤为５ ． ６３ , 水稻土为５ ． ８ , 潮土为４ ． ８３ ; 而对照处理的土壤肥力可持续性指数平均每年都下降, 红壤为５ ． ６ , 水稻土为６ ． ５８ , 潮土为４ ． ５６ 。不同施肥方式对土壤肥力可持续性指数的影响顺序为有机肥、有机肥配施化肥＞ 化肥＞ 参比土壤＞ 对照。     

蒽醌染料及其中间体絮凝菌的特性

本文研究所分离到的真菌ＮＸ１对蒽醌染料ＫＮＲ及其中间体溴氨酸的作用,并考察营养条件、体系ＰＨ等对ＮＸ１的生长及絮凝作用的影响,结果表明,ＮＺ１及溴氨酸有很好的絮絮凝效果,对ＰＨ的适应范围广,最佳碳、氮源分别为蔗粮主尿素。     

生物炭改良盐碱地研究与应用进展

盐碱地作为21世纪严重威胁粮食产量的农田问题土壤之一,分布广泛,具有极大的开发潜力.生物炭作为高效的新型土壤改良剂,在缓解土壤酸碱障碍、土壤污染治理、碳封存和肥料缓释等方面发挥了重要作用,有力地推动了盐碱地农业的可持续发展.近年来,关于生物炭改良盐碱地的研究和应用备受关注.但由于生物炭来源、结构和组分的复杂性和非均质性,其对盐碱地的改良效果存在极大的不确定,也缺乏关键机制的系统总结和深度探讨,这限制了生物炭技术在盐碱地改良中的进一步推广和应用.通过综合分析生物炭对盐碱地土壤理化性质、养分有效性和生物特征的影响,归纳总结生物炭和改性生物炭对盐碱地的改良效果及其提质增效作用,阐明生物炭在盐碱地改良中存在的可能机制,并对未来研究方向进行了展望,可为进一步研发绿色高效精准的盐碱地生物炭改良技术及其推广应用提供参考.     

氮添加对侵蚀退化红壤化学性质及芒萁叶功能性状的影响

蕨类植物芒萁(Dicranopteris dichotoma)是我国南方红壤侵蚀区重要的水土保持植物,但目前氮添加对芒萁叶功能性状及其基部土壤化学性质以及这二者之间关系的影响尚不清楚.以芒萁作为研究对象,采用盆栽实验,设置CK(0 g m-2 a-1)、N1(1.1 g m-2 a-1)、N2(2.3 g m-2 a-...     

ESTABLISHING POLLUTANT LOAD REDUCTION TARGETS FOR THE INIIAN RWER LAGOON,FLORIDA1

ABSTRACT. Establishment of seagrass‐based pollutant load reduction targets is a major aim of water quality management in the Indian River Lagoon (IRL) estuary. It is believed that light and water clarity are the limiting factors affecting seagrass abundance and distribution in the Lagoon. Thus, targeted reductions of nutrients, dissolved organic matter and for suspended sediments should achieve desired seagrass coverage goals. On an annual average, the Lagoon is receiving external loadings of 5,346, 771, and 54,408 metric tons per year of nitrogen (N), phosphorus (P), and total suspended solids (TSS), respectively. Most of the loadings are stormwater generated; thus, implementation of reduction targets will key in on major urban and agricultural stormwater systems. The process of developing targets requires the establishment of light requirements for seagrass. Two methods are being employed to develop such targets. One method is the application of a predictive, 3‐D model that accounts for the essential interactive processes of the Lagoon: hydrology, hydrodynamics, water quality, nutrient uptake/release, seagrass growth rates, and light attenuation. The other method is based simply on the comparison of loading rates between a developed sub‐basin with associated seagrass impacts and an undeveloped sub‐basin with adjacent healthy seagrass coverages. The latter method will provide the initial and preliminary targets that can be tested, confirmed, or modified by application of the 3‐D model.     

污水处理厂计算机仿真模拟研究

将上海市某城市污水处理厂的生产运行数据进行了计算机模拟,并将模拟结果中的COD及TSS、TN、NH3-N等组分的浓度与实测数据进行了比较。通过对模型参数进行修正和调整,仅改变ASM1数学模型中的4个参数,即取得了较好的预测效果。同时对城市污水处理厂进一步运用数学模型的可行性进行了讨论。     

南四湖表层底泥重金属和营养元素的多元分析

对南四湖不同湖区的20个表层底泥样品的重金属和营养元素浓度做了实验分析,并采用主成分分析等数理统计的方法对底泥重金属和营养元素进行了研究,揭示出南四湖不同湖区重金属和营养元素空间分布的特征.结果表明,整个南四湖的上级湖已经受到金属和营养元素的污染.其中南阳湖的汞和营养元素污染严重,铅、砷等次之;独山湖的营养元素污染最重;昭阳湖污染较轻.     

Critical Loads Exceedances in Germany and their Dependence on the Scale of Input Data

Critical load exceedances have been used as an effects-related parameter for guiding international air emission control negotiations. High-resolution critical load data are combined with low-resolution deposition data.This article shows that doing so systematicallyunderestimates `true' critical load exceedances as obtainedfrom combining critical load and deposition data of identicalhigh spatial resolution. 95th percentile critical loadexceedances in EMEP grids based on high resolution depositiondata are 60 and 150% higher (mean values for nutrientnitrogen and acidity, respectively) than critical loadexceedances based on the low resolution EMEP depositionmodel. The latter are used in international negotiations. Differences in individual EMEP grid squares vary betweeninsignificantly different from zero and 340%, depending onregional deposition and critical load characteristics andcritical load types (nutrient nitrogen versus acidity).Exceedances based on high-resolution deposition values arealso compared to EMEP grid averages of these values forforests only. This comparison excludes the effect ofsystematically higher depositions to forests. Still, thescale difference of (averaged, low-resolution) deposition and(high-resolution) critical loads data yields underestimatesof the 95th percentiles by on average ca. 20%.These systematic errors due to the scale dependence should beborne in mind when interpreting effects of internationalemission control measures.     

EFFECT OF A POINT SOURCE INPUT ON STREAM NUTRIENT RETENTION1

ABSTRACT: We examined the effect of a point source (PS) input on water chemistry and nutrient retention in Spavinaw Creek, Arkansas, during summer baseflows in 1998 and 1999. The nutrient uptake length (S_w) concept was used to quantify the impact of nutrient inputs in the receiving stream. We used an artificial injection upstream of the PS inputs to estimate background S and used the natural decline in nutrient concentrations below the PS to estimate the net nutrient uptake length (S_net). S_w for soluble reactive phosphorus (SRP) in the upstream reference section was O.75 km, but S_net ranged from 9.0 to 31 km for SRP and 3.1 to 12 km for NO₃‐N in the reach below the PS. S_net‐SRP was significantly correlated with discharge whereas S_net‐NO₃‐N was correlated with the amount of NO₃‐N enrichment from the PS. In order to examine specific mechanisms of P retention, loosely exchangeable P and P Sorption Index (PSI) of stream sediments were measured. Sediments exhibited little natural P buffering capacity (low PSI) above the PS, but P loading from the PS further reduced PSI. Loosely exchangeable P in the sediments also increased three fold below the PS, indicating sediments removed some water column P. The physical process of flow and sediment sorption apparently regulated P retention in Spavinaw Creek, whereas the level of N enrichment and possibly biotic uptake and denitrification influenced N retention. Regardless of the mechanism, Spavinaw Creek demonstrated little ability to retain PS‐added nutrients because net nutrient uptake lengths were in the km range.