The Austrian P budget as a basis for resource optimization

Phosphorus (P) is a finite and non-substitutable resource that is essential to sustaining high levels of agricultural productivity but is also responsible for environmental problems, e.g., eutrophication. Based on the methodology of Material Flow Analysis, this study attempts to quantify all relevant flows and stocks of phosphorus (P) in Austria, with a special focus on waste and wastewater management. The system is modeled with the software STAN, which considers data uncertainty and applies data reconciliation and error propagation. The main novelty of this work lies in the high level of detail at which flows and stocks have been quantified to achieve a deeper understanding of the system and to provide a sound basis for the evaluation of various management options. The budget confirms on the one hand the dependence of mineral P fertilizer application (2 kg cap⁻¹ yr⁻¹), but it highlights on the other hand considerable unexploited potential for improvement. For example, municipal sewage sludge (0.75 kg cap⁻¹ yr⁻¹) and meat and bone meal (0.65 kg cap⁻¹ yr⁻¹) could potentially substitute 70% of the total applied mineral P fertilizers. However, recycling rates are low for several P flows (e.g., 27% of municipal sewage sludge; 3% of meat and bone meal). Therefore, Austria is building up a remarkable P stock (2.1 kg P cap⁻¹ yr⁻¹), mainly due to accumulation in landfills (1.1 kg P cap⁻¹ yr⁻¹) and agricultural soils (0.48 kg P cap⁻¹ yr⁻¹).     

Phosphorus resources,their depletion and conservation,a review

Yearly, about 22 × 10¹² g phosphorus (P) from mined fossil phosphate resources are added to the world economy. The size of remaining fossil phosphate resources is uncertain but practically finite. Thus, fossil P resources may become depleted by ongoing mining. Despite calls for resource conservation, fossil P resources have been depleted at an increasing rate. Geographically, fossil P supply and demand are distributed in an increasingly uneven way, which has geopolitical consequences and may well affect security of supply. Current use of P gives rise to negative environmental impacts due to P losses from the economy and contaminants derived from fossil P resources. There may also be negative impacts on human health. Reducing the demand for fossil phosphorus may reduce environmental burdens and may improve the future security of supply. Technically speaking, there is much scope for the reduction of current demand for fossil P resources. Limiting consumption of P to essential uses, increased efficiency of agricultural use and increased recycling of P may substantially contribute to the reduction of demand for fossil P resources. Recycling of P has to face concerns regarding the efficiency of P recovery, pathogenic organisms and contaminating substances. Much work remains to be done to effectively address those concerns.     

平原感潮河网地区不同土地利用下营养盐迁移特征

分别在南通平原河网地区选择典型非圩区开展野外原位试验,用野外观测和室内分析相结合的方法,研究平原非圩区典型试验小区不同土地利用下营养盐在自然降雨—径流驱动下迁移的时空分布特征.结果表明,导致营养盐迁移时空分布存在显著差异的主要原因为不同的土地利用类型、施肥条件及植被覆盖度等,不同土地利用下的径流量差异是导致营养盐迁移通...     

沉积物中磷负荷及其释放对水质的影响

以华东师范大学校河为研究对象，通过野调研与室内模拟实验相结合，研究了校河沉积物中磷负荷量，释放量与释放速度以及温度和水体扰动对其影响，并探讨了沉积物中磷释放对校河水质的影响，为校河的富营养化防治提供科学依据。     

不同丙酸/乙酸对聚糖菌长/短期代谢的影响

在3个SBR反应器(即SBR-A,SBR-C和SBR-E)中,以3种不同比例的丙酸/乙酸中长期驯化活性污泥使之富集聚糖菌,对丙酸/乙酸对聚糖菌的长期和短期代谢的影响进行了研究.结果表明,长期高丙酸/乙酸驯化导致聚糖菌厌氧消耗的糖原量和合成的聚β羟基烷酸酯(poly-β-hydroxyalkanoates, PHA)的量都较少,在好氧段积累的糖原量和降解的PHA的量也较小,并且对聚糖菌的脱氢酶活性、生长速率及对有机酸的利用能力等都有抑制作用.当进水中的丙酸与乙酸的碳摩尔数相同时,单位生物量利用乙酸的速率较丙酸快.不同丙酸/乙酸对聚糖菌代谢的短期影响的研究表明,当进水中乙酸浓度突然提高时,长期以高丙酸/乙酸驯化的聚糖菌可以直接利用乙酸参与代谢,但长期以低丙酸/乙酸驯化的聚糖菌则无法快速利用丙酸.提高进水中丙酸/乙酸有可能成为有效抑制聚糖菌生长并提高增强生物除磷系统稳定性的一种策略.     

进水C/P对SNEDPR系统脱氮除磷性能的影响

为了解不同进水C/P条件下同步硝化内源反硝化除磷(SNEDPR)的脱氮除磷特性.以实际城市污水为处理对象,采用延时厌氧(180 min)/低氧(溶解氧0.5~1.0 mg·L~(-1))运行的序批式反应器(SBR),考察了进水C/P(分别为60、30、20、15、10)对系统C、N、P去除特性的影响.结果表明:适当降低进水C/P(由60降至30)有利于提高系统内PAOs竞争优势.当C/P为30时系统除磷性能最高,厌氧段释磷速率(PRR)和好氧段吸磷速率(PUR,以P/MLSS计,下同)分别高达3.5mg·(g·h)-1和4.2 mg·(g·h)-1,出水PO3-4-P浓度均低于0.3 mg·L~(-1),且PPAO,An高达88.1%;但进一步降低进水C/P至10时,PO3-4-P去除率和PPAO,An分别由38.1%和82.4%降低至3.1%和5.3%,PRR和PUR分别仅为0.2 mg·(g·h)-1和0.24mg·(g·h)-1,系统表现出较差的除磷性能.降低C/P对系统COD去除性能没有影响,COD去除率稳定在85%左右.此外,当C/P由60降低至20时,系统硝化性能变差,表现为出水NH+4-N和NO-2-N浓度分别由0和6.9 mg·L~(-1)升高至5.1 mg·L~(-1)和16.2 mg·L~(-1);而当C/P进一步降低至10时,系统硝化性能得以恢复,但亚硝积累特性遭到破坏,表现为出水NH+4-N和NO-2-N浓度逐渐降低为0,但出水NO-3-N浓度由0.08 mg·L~(-1)升高至14.1 mg·L~(-1).SNED率先由62.1%降低为36.4%后又逐渐提高至56.4%.C/P低于15时,有利于提高GAOs的竞争优势,且C/P由20降至10时系统脱氮性能得以恢复,原因在于GAOs内源反硝化作用的增强.     

Bioelectrochemical acidolysis of magnesia to induce struvite crystallization for recovering phosphorus from aqueous solution

A novel struvite crystallization method induced by bioelectrochemical acidolysis of magnesia(MgO) was investigated to recover phosphorus(P) from aqueous solution using a dual-chamber microbial electrolysis cell(DMEC). Magnesium ion(Mg~(2+)) in the anolyte was firstly confirmed to automatically migrate from the anode chamber to the cathode chamber, and then react with ammonium(NH+4) and phosphate(PO_4~(3-)) in the catholyte to form struvite. Recovery efficiency of 17.8%–60.2% was obtained with the various N/P ratios in the catholyte. When MgO(low solubility under alkali conditions) was added into the anolyte, the bioelectrochemical acidolysis of MgO naturally took place and the released Mg~(2+)induced struvite crystallization in the cathode chamber for P recovery likewise.Besides, there was a strong linear positive correlation between the recovery efficiency and the MgO dosage(R~2= 0.935), applied voltage(R~2= 0.969) and N/P ratio(R~2= 0.905). Increasing the applied voltage was found to enhance the P recovery via promoting the MgO acidolysis and the released Mg~(2+)migration, while increasing the N/P ratio in the catholyte enhanced the P recovery via promoting the struvite crystallization. Moreover, the electrochemical performance of the system was promoted due to more stable anolyte pH and lower pH gradient between the two chambers. Current density was promoted by 10%, while the COD removal efficiency was improved from 78.2% to 91.8% in the anode chamber.     

Phosphorus removal from sediments by Potamogeton crispus: New high-resolution in-situ evidence for rhizosphere assimilation and oxidization-induced retention

Macrophytes are usually chosen for phytoremediation tools to remove P in eutrophic aquatic ecosystems, but the lack of test methods hinders the understanding of removal mechanism and application. In this study, we used the novel technologies combined of Diffusive gradients in thin films (DGT), Planar optode (PO), and Non-invasive micro-test technology (NMT) to explore P dynamics in water-sediment continuum and rhizosphere of Potamogeton crispus over time. Results of the high-resolution in situ measurement showed that labile P(LP_DGT) fluxes at the surficial sediment significantly decreased from approximate 120, 140, and 200 pg/ (cm²?sec) via 30 days incubation period to 17, 40, and 56 pg/(cm²?sec) via that of 15 days. Obvious synchronous increase of LP_DGT was not detected in overlying water, suggesting the intense assimilation of dissolve reactive P via root over time. PO measurement indicated that O₂ concentration around the rhizosphere remarkably increased and radially diffused into deeper sediment until 100% saturation along with the root stretch downwards. NMT detection of roots showed the obvious O₂ inflow into root tissue with the uppermost flux of 30 pmol/(cm²?sec) from surroundings via aerenchyma on different treatment conditions. Different from previous reports, gradually saturating O₂ concentrations around the rhizosphere was principally driven by O₂ penetration through interspace attributing to root stretch downward rather than root O₂ leakage. Increased O₂ concentrations in deep sediment over time finally induced the oxidization of labile Fe(II) into Fe(III) bound P and local P immobilization.     

Preliminary investigation of phosphorus adsorption onto two types of iron oxide-organic matter complexes

Iron oxide(FeO)coated by natural organic matter(NOM)is ubiquitous.The associations of minerals with organic matter(OM)significantly changes their surface properties and reactivity,and thus affect the environmental fate of pollutants,including nutrients(e.g.,phosphorus(P)).In this study,ferrihydrite/goethite-humic acid(FH/GE–HA)complexes were prepared and their adsorption characteristics on P at various p H and ionic strength were investigated.The results indicated that the Fe O–OM complexes showed a decreased P adsorption capacity in comparison with bare Fe O.The maximum adsorption capacity(Q_(max))decreased in the order of FH(22.17 mg/g)FH-HA(5.43 mg/g)GE(4.67 mg/g)GE-HA(3.27 mg/g).After coating with HA,the amorphous FH–HA complex still showed higher P adsorption than the crystalline GE–HA complex.The decreased P adsorption observed might be attributed to changes of the Fe O surface charges caused by OM association.The dependence of P adsorption on the specific surface area of adsorbents suggests that the Fe O component in the complexes is still the main contributor for the adsorption surfaces.The P adsorptions on Fe O–HA complexes decreased with increasing initial p H or decreasing initial ionic strength.A strong dependence of P adsorption on ionic strength and p H may demonstrate that outer-sphere complexes between the OM component on the surface and P possibly coexist with inner-sphere surface complexes between the Fe O component and P.Therefore,previous over-emphasis on the contributions of original minerals to P immobilization possibly over-estimates the P loading capacity of soils,especially in humic-rich areas.     

辽东湾海域生物体内石油烃污染状况

根据2013年8月对辽东湾海域拖网采集的127个生物体样品石油烃含量测试结果,结合历史调查数据,分析该海区生物体内石油烃含量水平、分布特征和变化趋势,评估生物体石油烃污染程度.结果表明:调查海区生物体内石油烃含量为2.76~41.81 mg·kg-1,平均为12.19mg·kg-1;整体石油烃含量具有软体腹足纲甲壳动物蟹类软体头足甲壳动物虾类鱼类,内脏组织高于肌肉组织的特点;生物体内石油烃含量与沉积物中石油烃含量存在显著相关性,与水体石油烃含量不存在明显相关性;年际变化趋势分析显示2012年软体类和甲壳类生物体石油烃含量高于2007年和2013年,表明调查海域2012年以前存在明显的石油烃输入;与国内其他海域相比,调查海域生物体石油烃含量较高.