反硝化除磷污泥的缺氧吸磷性能研究

为探讨反硝化除磷过程中污泥的缺氧吸磷性能,利用厌氧/缺氧强化驯化得到的反硝化除磷污泥,通过间歇性试验考察不同电子受体类型、不同污泥浓度(MLSS)对吸磷过程的影响。试验结果表明,缺氧条件下反硝化除磷菌(DPB)利用硝酸盐作为电子受体能够彻底吸磷,其吸磷速率约为好氧吸磷的59%;若以亚硝酸盐为电子受体,浓度较低时(10.6 mg/L)的吸磷速率与硝酸盐为电子受体时相当,但较高的亚硝酸盐浓度(22.6 mg/L)会抑制反硝化除磷过程;适当提高污泥浓度能加快缺氧吸磷速度,而过高的污泥浓度会降低污泥对氮、磷的比去除速率,故应将MLSS控制在合理的范围内。     

一种封闭式选煤车间的设计

近年来,随着国家对煤炭行业控制环境污染的条件越来越严格,为了更有效的治理煤场环境污染,改善煤场周边地区环境质量,根据国内已建成的大型封闭厂房的设计经验,提出一种封闭式煤炭风选车间,车间采用轻型门式钢架结构设计,常规经济柱距6m,抗风柱柱距7．5m,室内净高10m。工程长度90m,跨度35m,屋盖系统采用钢桁架结构体系,单层压型彩色钢板封闭。封闭车间同时配套通风除尘系统,有效降低煤尘量。     

苏柳172和垂柳对Pb的吸收动力学特性及有机酸的影响

采用溶液培养的方法研究了苏柳172（Salix jiangsuensis CL‘J172’）和垂柳（Salix babylonica Linn）的Pb吸收动力学、Pb在根区的分布以及低分子量有机酸对Pb吸收的影响.结果表明,在溶液Pb浓度为0.25—100μmo.lL-1时,两种柳树对Pb的吸收动力学都呈非饱和曲线,积...     

Effect of collection system on mineral content of biowaste

The EU is committed to encourage biological treatments of organic waste as an alternative to landfill and also to enhance organic matter recycling. When these wastes are composted, the composition of the initial raw materials is very important in order to obtain a good quality product. In this article, the mineral composition of the organic fraction obtained from source-sorted collection (SC) and the organic fraction mechanically separated (MS) from mass-collected municipal solid waste was evaluated. Also, the compositions of these 2 raw materials that are used in the current Spanish municipal solid waste biological treatment facilities were compared. The mineral elements analyzed were the total content of the heavy metals Zn, Cu, Ni, Cr, Pb and Cd, and the plant nutrients P, K, Na, Ca, Mg, Fe and Mn. The results obtained were expressed on dry matter basis and on mineral matter basis. Important differences were detected between SC and MS samples, on both dry and mineral matter basis. In general, nutrient contents are higher in SC than in MS, and heavy metal contents are significantly lower in SC. Our results also support the idea that the heavy metal migration from the non-compostable materials to the decomposable matrix takes place from the beginning of the process while both types of materials are in contact.     

基于机器学习方法的小麦镉富集因子预测

应用机器学习方法解析区域土壤-小麦系统镉(Cd)富集特征有助于风险决策的准确性和科学性.基于区域调查,构建了Freundlich-type转移方程、随机森林(RF)模型和神经网络(BPNN)模型对小麦Cd富集因子(BCF-Cd)进行预测,验证不同模型的预测精度并评估其不确定性.结果表明,RF(R²=0.583)和BPNN(R²=0.490)模型预测性能均优于Freundlich转移方程(R²=0.410).重复训练结果显示RF和BPNN平均绝对误差(MAE)和均方根误差(RMSE)较为接近,但RF(R²为0.527～0.601)较BPNN(R²为0.432～0.661)模型精度和稳定性更高.特征变量重要性分析显示多重因素的共同作用导致小麦BCF-Cd的异质性,其中土壤磷(P)和锌(Zn)是影响小麦BCF-Cd变化的关键变量.参数优化可进一步提高模型精度、稳定性和泛化能力.     

Editorial: Effect of root anatomy and apoplastic barrier development on cadmium uptake in rice

<正>Cadmium (Cd) is a toxic metal with high mobility from soil and known translocation into plants (Song et al., 2015).Because the main source of human exposure to Cd is from food consumption, there has been increased research examining Cd uptake in agricultural plants (Li et al., 2014; Rizwan et al., 2016; Song et al., 2015). Rice (Oryza sativa L.) has been identified as a major crop that contains relatively high     

Tuning of activated sludge in winter based on respirogram profiles under standard and site temperatures

Respirograms of activated sludge OUR_ x~Tand OUR_x~(20)were measured under site(T) and standard(20°C) temperatures, respectively, and the predicted standard temperature respirogram OUR_( x,cal)~(20)was also calculated using the Arrhenius equation. These respirogram profiles reveal more information than effluent quality. A decrease of OUR_ x ~(20)is a critical alarm signal for the loss of pollutant removal capacity, and a sudden increase of the predicted value OUR_( x,cal)~(20)is an alarm signal for the unrecoverable deterioration of biomass. The sign of OUR_x~(20)–OUR_(x,cal)~(20)can be used for selection of tuning strategies. For example, a negative value of OUR_x~(20)–OUR_( x,cal)~(20)indicates that doubling biomass is difficult,thus strategies such as extending the reaction time with limited available biomass is preferred. The findings in this study elucidated the respiration profile of activated sludge under changes of temperature and can be effectively used for the stable operation of Wastewater Treatment Plants under cold temperatures and seasonal variations.     

高效藻类塘磷酸盐去除机理研究

从磷酸盐化学沉淀和藻类吸收两个方面探讨了高效藻类塘中磷酸盐的去除机理。首先通过化学沉淀及其解析解释了高效藻类塘中pH与磷酸盐浓度昼夜变化规律；其次测定了pH=7．5时藻类对磷酸盐的日均吸收速率；最后对高效藻类塘中磷酸盐浓度的变化规律进行了总结。     

Experimental Investigation of Potassium and Nitrate Dynamics in A Headwater Stream in Mid-Wales

Potassium and nitrate were added experimentally to a small moorland stream in the headwaters of the River Wye, mid-Wales, during summer and winter low-flow conditions. Nutrient losses at three downstream sampling locations were calculated using concentrations of an added bromide tracer to correct for dilution effects. During the summer experiment, approximately 18% of the added nitrate and 58% of the potassium were removed from the stream water between the point of addition and the catchment outlet. During the winter experiment, nitrate depletion was not observed and the added nitrate travelled along the stream at the same rate as the bromide tracer, while approximately 93% of the added potassium passed through the stream but, at a slower rate than the bromide and nitrate. the results show that in-stream processes, probably related to biological activity of macrophytes and microflora, can regulate stream water concentrations of nitrate and potassium in the summer under stable flow conditions. During the winter, no removal of nitrate or potassium was observed but ion exchange processes involving biofilms, Sphagnum and/or stream sediment may explain the temporary retention of potassium within the stream channel. If similar ion exchange processes operate at high flows, they may account for the hysteresis relationship observed between potassium and discharge during storm events in many upland streams.     

FNA对好氧吸磷的长期抑制及污泥吸磷方式转化

本研究采用交替厌氧/好氧(An/O)SBR反应器,在21~23℃的条件下启动系统并长期投加亚硝酸盐,考察游离亚硝酸(FNA)对系统好氧吸磷性能的长期抑制作用及驯化后污泥吸磷方式的转化.结果表明,投加FNA后,污泥的释磷和吸磷能力不仅未受到抑制,比释磷速率和比吸磷速率反而高于投加前.FNA浓度(以HNO2-N计)低于0.53×10-3mg·L-1时,系统除磷率均大于96.9%;当FNA浓度提高至0.99×10-3、1.46×10-3、1.94×10-3mg·L-1时,系统除磷率均会大幅下降,分别经过50、12、30 d的运行,除磷率恢复至64.42%、67.33%、44.14%,说明抑制作用导致的除磷性能恶化可以恢复且长期驯化作用能缩短恢复过程.值得注意的是,在低于1.46×10-3mg·L-1范围内,随着FNA投加量的提高,好氧段亚硝酸盐的损失量不断增大.研究还发现,经FNA长期抑制的好氧除磷系统内污泥吸磷方式发生转变,硝酸盐型和亚硝酸盐型缺氧吸磷能力分别为驯化前的3.35倍和3.86倍,说明长期投加FNA有利于富集以NO-2为电子受体的反硝化聚磷菌;而且,长期驯化有利于系统内污泥的沉降.