底泥营养盐的释磷对富营养化湖泊的影响

富营养化是中国湖泊的重大环境问题。当湖泊的污染外源受到控制以后，由于沉积物（底泥）中营养盐内负荷的存在和释放，湖泊仍然可以发生富营养化。底泥营养盐就成为湖泊富营养化的主导因子，特别是溶解态的磷会逐步释放，成为水体富营养化的主导因子。沉积物中磷的循环在一定程度上决定着富营养化的进程，对水体磷含量有深刻的影响。结合国内外研究动态，对底泥磷形态、磷释放与水体水质的关系作了概述，并对底泥磷释放的研究方向以及控制湖泊富营养化发表了一些见解。     

湖泊底泥磷释放及磷形态变化

为研究底泥中内源性磷释放对城市景观水体富营养化的影响,以西安市曲江南湖为对象,采用底泥磷形态标准测试方法(SMT)分析了磷的赋存形态,通过模拟实验探究了在不同环境条件(温度、pH和溶解氧)下磷形态变化的特征。结果表明:温度升高促进内源磷的释放,在夏季加剧水体富营养化程度;碱性条件有利于磷的释放,增大补给水源可减少底泥释磷量;厌氧环境下底泥释磷量是好氧时的3.96倍;Al-P和Ca-P较稳定,在酸性条件下会加速其溶解;NH+4-P、Fe-P和OrgP受溶解氧、pH和温度影响较大,其吸附与释放能力有明显的差异。     

底泥磷形态及分布特征对水体富营养化的影响

富营养化是当今中国浅水湖泊面临的重大污染问题。结合国内外的报道,通过大量湖泊水库的实地调查,对各种磷形态的性质和分布特征及转移规律作了深入研究,介绍了水体底泥中磷的物理化学性质、磷的存在形式与转化、磷的分布特征、磷在不同粒径底泥下的含量及转移趋势,为探明水体富营养化提供科学而有力的依据。最后指出了其对湖泊富营养化的影响,并对控制湖泊富营养化提出了见解。     

城市富营养化水体底泥净化磷效果

以城市富营养化水体底泥和上覆水为材料,研究了扰动状态下底泥对外源磷的净化效果。结果表明,扰动状态下,200 g湿底泥从上覆水中共吸收外源磷19.92 mg,而静止状态下,200 g湿底泥仅吸收了13.61 mg。然而,厌氧状态下,前者内源磷释放量仅占吸收磷量的43%,而后者则高达63.4%。说明底泥扰动不仅强化了底泥对外源磷的吸收,而且也强化了内源磷的固定能力。这与扰动状态下外源磷在不同形态磷间的数量分布有关。底泥扰动和静止状态下,难释放态磷(HCl-P、闭蓄态Fe/Al-P)的增加量分别占底泥吸收外源磷量的36%和21%。     

青山水库底泥磷释放与库区水体磷浓度的关系

通过对青山水库底泥磷释放特性的实验结果分析,对照库区水体浓度监测的数据,确定了库区各测点底磷释放量与水体浓度之间的关系,进而为库区环境总量控制与各支流的分配计算提供了依据。同时也为防止水库的进一步富营养化,进而改善水质提供了新的思路。     

底泥扰动状态下内源磷释放过程模拟研究

为了揭示底泥扰动对内源磷释放的影响,通过室内实验模拟了底泥多次扰动状态的整个过程。结果表明,底泥扰动刚结束(0 h),溶解态磷(DIP、DTP)显著降低;底泥扰动结束后(1、6和24 h),溶解态磷发生"滞后释放"。第1 d,在1、6和24 h采样时段,DIP、DTP的"滞后释放量"最大,分别达到20.0 1mg/kg,22.12 mg/kg,16.85 mg/kg和17.21 mg/kg,22.12 mg/kg,9.69 mg/kg。第2 d,该释放量分别降低了44.80%~57.87%和42.52%~61.24%。随着底泥扰动次数的增加,溶解态磷的"滞后释放"逐渐转变为"负释放",同时,DIP/TP和DTP/TP逐渐降低。这说明,底泥扰动应该是促进了上覆水中溶解态磷向底泥的迁移和强化了底泥对磷的固定作用,同时降低了水体中磷的可生物利用性。因此推测,底泥扰动延缓了水体富营养化的发展进程。     

阳宗海沉积物中磷的稳定性

絮凝剂(Fe Cl3)治理阳宗海砷污染的过程中,水体中的磷被大量沉积进入底泥,弄清其是否会在环境条件变化后发生反溶形成二次污染对湖泊富营养化防治具有重要意义。通过模拟实验模拟泥-水界面p H变化、物理扰动和微生物活动的变化,旨在分析这些环境因子变化对沉积物中磷溶出的影响。结果表明,阳宗海水体在目前这种磷浓度下,底泥的磷会随时间的增加而溶出再次造成水体磷污染,当暴露在清洁水条件下时磷的释放率会增加;这种由于絮凝剂吸附沉淀到湖底的磷,在上覆水p H增加0.5时底泥磷解吸附释放速率增加;每年秋季湖泊上下层水的交换活动会造成水体磷浓度的季节性升高,形成不可忽视的磷内源。而夏季水温分层导致湖泊底部厌氧,使厌氧微生物活性增强,这将进一步促进底泥中磷的释放。     

富营养化水体清淤后的微生物脱氮技术应用

景观水体清淤带来的主要负面影响是水体富营养化。为了探索清淤及微生物修复的组合应用,通过在实验室建立模型,分别研究了清淤、微生物修复及二者结合处理对富营养化水体水质的影响。结果表明,清淤能降低氨氮的释放。底泥微生物的活动会促进氨氮的释放,增加水体的富营养化风险。单纯清淤会使底泥的硝化作用增强,但同时使反硝化作用减弱,降低水体总氮的去除能力。因此,通过投加氮循环微生物可促进清淤后的反硝化作用,消减湖泊底泥及上覆水中的氮素含量,达到修复富营养化湖泊的目的。研究结果表明,清淤和微生物修复技术结合使用,可减少水体氮素积累,避免蓝藻爆发,是富营养化水体清淤防控的一种有效措施。     

红枫湖底泥磷负荷释放

为了研究高原湖泊底泥沉积物中磷的释放负荷,对贵州红枫湖区10个地区的沉积物进行了磷形态分析。选取10个采样点中5个典型区域,研究结果表明,底泥中各形态磷占总磷比例Org-P为58.6%,NaOH-P为29.91%,Ca-P为11.48%,底泥中主要的磷形态为有机磷。上覆水溶解性总磷酸盐(TSP)与底泥中各形态磷的相关性研究表明,底泥中的Ca-P与上覆水中的TSP几乎没有相关性,NaOH-P与Org-P与上覆水的TSP有较高的相关性(R2>0.94),而底泥中的总磷(TP)与上覆水中的TSP相关性最高(R2>0.98),底泥中这种形态的结构有利于抑制底泥的释放。研究表明,在10点位样品中,间隙水中TP和SRP(溶解性正磷酸)浓度远大于上覆水体中相应磷形态的浓度,间隙水中TP平均浓度为0.37 mg/L,SRP平均浓度为0.18 mg/L,上覆水体中TP平均浓度为0.10 mg/L,SRP平均浓度为0.02 mg/L,间隙水中TP、SRP与上覆水中TP、SRP存在了一种浓度梯度。     

四平市二龙湖底泥磷释放研究

采用室内实验模拟法对四平市二龙湖富营养化限制因子磷的底泥释放速率及释放量进行了研究,并研究在种环境因子(温度、pH、DO和扰动因素)影响下底泥磷的释放规律。结果表明,(1)二龙湖年平均底泥释磷量为208·78g,最大释磷率为0·889μg/g(T=20℃,pH=8,DO为4·68mg/L);(2)自然和人为的扰动因素会促进底泥的磷释放;(3)H在弱酸至中性范围内底泥释磷量最小,酸性和碱性条件都有利于磷的释放;(4)随着温度的升高底泥释磷量增大;(5)厌条件比好氧条件更有利于磷的释放。     

反硝化聚磷一体化设备中的聚磷菌

研究了新型生物脱氮除磷新工艺反硝化聚磷一体化设备中反硝化厌氧池活性污泥的兼性厌氧微生物组成，数量及其在该除磷系统中功能，结果表明，稳定运行期反硝化厌氧池内活性污泥混合液的兼性厌氧微生物总数大大多于启动期，稳定期和启动期分离的兼性厌氧微生物有假单胞菌属，副球菌属和肠杆菌科，通过对三种纯菌株进行吸放磷研究，三种菌都有不同程度的聚磷功能，说明反硝化菌也具有聚磷作用。     

黄磷尾气中总磷及磷化氢的测定

电炉法生产黄磷的过程中会产生大量的尾气,其主要成分是CO(85％～95％)．还有磷、硫、氟、砷、CO2、N2、H2等杂质。黄磷尾气中的磷主要以P4、PH3、P2O5等形式存在。一般尾气经过水洗后．P2O5大部分被水吸收,尾气中主要是P4、PH3。采用分光光度法分析总磷和气体检测管测定磷化氢,效果良好。     

Surface water phosphorus dynamics in rice fields receiving fertiliser and manure phosphorus

A long-term randomised block field experiment was established in 1997 to study the dynamics of total P and dissolved P in the surface waters of rice fields receiving two application rates of fertiliser P and one rate of combined fertiliser and manure P. Preliminary results from the first two crops show that concentrations of both total P and dissolved P in the surface waters increased significantly following P application, especially during the first 2 weeks after application. P concentrations subsequently declined sharply within about 10 days, then declined steadily and remained almost constant from about 1 month after application. The initial increase in P concentration of surface waters was higher with increasing rate of fertiliser P, and the P concentration at the highest fertiliser rate peaked within about 1 week of application. The elevated P concentrations following fertiliser P application declined more rapidly than those following the combined application of fertiliser and manure P. When fertiliser and manure P were applied together, about 7 days later the surface water P concentrations were significantly higher than when the same rate of P (or double) was applied as fertiliser only. Disturbance of the surface soil by hand harrowing further increased the P concentrations in surface waters, with a subsequent decline to a steady value after about 1 week. Application of P fertiliser to the high P status soil in this experiment gave no crop yield response and may have increased the risk of pollution of adjacent surface waters through drainage from heavy rainfall events during the rice growing season. Therefore, fertiliser P should not be applied to such soils. If, however, fertiliser or manure P is applied, the application should be made during the dry winter to reduce P losses. Manure should be applied with particular care because of the higher risk of P losses to surface water arising from the relatively long period of high P concentrations in surface waters and the potential for greater release of P to field surface waters from the soil. Hand harrowing should also be avoided during wet weather to protect water quality.     

污泥消化液的磷浓度对anammox-HAP系统磷回收的影响

厌氧氨氧化-羟基磷酸钙(anammox-hydroxyapatite,anammox-HAP)技术可实现污泥厌氧消化液高效自养脱氮同步磷回收.污泥厌氧消化液中磷的浓度与污泥性质、厌氧消化过程相关,变化范围很大.为探索anammox-HAP 系统中的磷回收效率,通过基于anammox-HAP长期运行的膨胀颗粒污泥床反应器...     

Investigating phosphorus limitation in a fixed bed filter with phosphorus and nitrogen profile measurements

In 2000, the European Union adopted the European Water Framework Directive (WFD) (European Commission, 2000). The WFD focuses on increasingly stringent nutrient standards including ultra low nitrogen (< 2.2 mg N-total/L) and phosphorus concentrations (< 0.15 mg total phosphorus/L) in receiving surface waters and in relevant point sources like wastewater treatment plant (WWTP) effluent. Expansion of WWTPs with advanced post-treatment processes, like effluent filtration, is widely proposed to meet possible future effluent discharge standards. When combining biological nitrate-nitrogen and chemical phosphorus removal in one filter, phosphorus limitation in the denitrifying process may occur. This study investigated where in the filter bed and under which conditions phosphorus limitation occurs. Profile measurements for nitrate, nitrite, and orthophosphorus (PO4-P) combined with chemical oxygen demand (COD) and 02 were conducted. Results showed that the required PO4-P/NOx-N ratio is approximately 0.006 mg/mg after phosphorous precipitation and flocculation. Profile measurements have proven to be an applicable and useful tool. It showed how nitrate and orthophosphorus are removed through the filter bed based on the PO4-P/NOx-N ratio. When orthophosphorus is removed more rapidly and efficiently compared to nitrate, the PO4-P/NOx-N ratio decreases. When PO4-P/NOx-N ratio thresholds are approximately 0.006 mg/mg for a certain period of time and water temperatures varied significantly, orthophosphorus limitation may occur. Changing the filter-bed configuration or decreasing the coagulant dosage can prevent limitation of the denitrifying process because of a phosphorous shortage.     

Wet deposition of phosphorus in Florida

Wet deposition of phosphorus was measured at 10 sites across Florida originally established as part of the Florida Atmospheric Mercury Study conducted between 1992 and 1996. Monthly integrated samples were collected and analyzed using a total analytical protocol that incorporated “clean lab” conditions for sample equipment preparation and Aerochem Metrics collectors modified for suitability to use for ultra-trace elements. Samples also were collected aboard 15 m towers to minimize any influence on measured deposition by insects, etc., and locally originating particles that do not contribute to true net deposition. Extensive replication of samples in the field was conducted (ca. 83%). The average absolute difference between replicates was 16.2%, with a median absolute difference of 9.5%. Replicate precision was poorest for concentrations above 0.080 mg P l⁻¹, suggesting that concentrations above this level are contaminated.The wet deposition concentrations and fluxes of phosphorus measured in this study are appreciably lower than those reported by previous investigators for wet deposition in Florida, and lie at the lower end of measurements reported in the recent literature. For example, the volume weighted mean concentration and flux for wet deposition across all our study sites averaged 0.005 mg P l⁻¹ and 7.5 mg P m⁻² yr⁻¹, respectively, which is approximately 50% and 32% lower than that reported by Hendry et al. (1981 in Atmospheric Pollutants in Natural Waters. Ann Arbor Science, Ann Arbor. MI, pp. 199–215). Our lower measurements likely reflect three factors: (1) the ultra-trace element sampling and analytical protocols; (2) improved collector design to eliminate sampling artifacts (e.g., splash-off contamination and transfer of contaminants from the dry bucket); and (3) placement of collectors off the ground surface. Lower VWM concentrations were observed near the Florida coast; otherwise, strong spatial patterns across the state were absent. Seasonal variations in VWM also were not pronounced, although deposition fluxes were highest during the summer wet season in response to the strong seasonal distribution of rainfall.     

Effect of low levels of dietary available phosphorus on phosphorus utilization,bone mineralization,phosphorus transporter mRNA expression and performance in growing pigs

A study was conducted to examine the effects of different dietary levels of available phosphorus (aP) on P excretion, bone mineralization, performance and the mRNA expression of sodium-dependent P transporters in growing pigs. Sixty-day old growing pigs (n = 54) with an average initial BW of 19.50 ± 1.11 kg were randomly allocated to a control diet (C) containing 0.23% available phosphorus (aP), T1 containing 0.17% aP and T2 containing 0.11% aP. There were 6 pens per treatment with 3 pigs per pen. Body weight and feed intake were measured weekly. At the end of each week, one pig from each pen was housed in a metabolic crate for 24 h to collect fecal and urine samples and then sacrificed to obtain third metacarpal (MC3) bones and jejunal and kidney samples. Bones were scanned by Dual Energy X-ray Absorptiometry (DEXA). Fecal and urine samples were sub-sampled and analyzed for P content. The expression of P transporter mRNA in jejunum and kidney samples was measured using quantitative real-time polymerase chain reaction (qRT-PCR). Data were analyzed using GLM procedure of the Statistical Analysis System (SAS Institute version 9.2). Pigs fed the T2 diet had reduced (P < 0.05) average daily gain (ADG) and gain to feed (G:F) compared to those fed the C diet during week 2. Overall, ADG and G:F were also reduced (P < 0.05) in pigs fed the T2 diet compared to those fed the C and T1 diets. Bone mineral density (BMD) and bone mineral content (BMC) were reduced (P < 0.05) in pigs fed the T2 diet compared to those fed the C diet throughout the experiment. At week 1, jejunal mRNA expression of Na (+)-dependent phosphate transporter 2 (SLC34A2) was increased (P < 0.01) in pigs fed the T2 diet compared to C diet. Renal mRNA expression of Na(+)-dependent phosphate transporter 1 (SLC34A1) and SLC34A3 were increased (P < 0.05) in pigs fed the T2 diet compared to those fed the C diet at week 2 and was accompanied by lower (P < 0.05) urinary P in pigs fed the T2 diet during week 2 and week 3. In conclusion, growing pigs are highly sensitive to low dietary P as shown by reduced ADG, bone mineralization and urinary P level, but moderate reduction in dietary P up to 0.17% aP in the diet has the potential to reduce environmental pollution by reducing P concentration in swine manure and without compromising performance.     

Determining algal-available phosphorus in pulp and paper mill effluents: algal assays vs routine phosphorus analyses

We determined the potentially algal-available P (P(aa)) in pulp and paper mill effluents by two bioassay techniques (a dual-culture assay and a batch approach) and compared it with chemically analysed P (total P, total dissolved P, reactive P, dissolved reactive P and dissolved hydrolysable P). The mean P(aa) given by the dual-culture assay was within a 40% range of that given by the batch approach. The P(aa) obtained by both bioassays differed from total P. Dissolved reactive P appeared to be the most readily available chemical P fraction, but other P fractions also contributed to P(aa). The analysis of reactive P, which involves direct staining of an unfiltered sample, best approximated the P(aa) given by the dual-culture assay (relative error 9%). The results suggest that assessment of eutrophying effluent P can be improved by analysing simple chemical P fractions in wastewater. The fractions to be analysed, however, may be site specific.     

污水中磷的回收和利用途径

综述了近年来污水中磷回收的主要技术方法,重点针对磷酸铵镁结晶法,对磷酸铵镁的形成、用途及该方法的可行性做了详细的介绍与评述.同时,阐述了利用磷酸盐溶解微生物,实现磷产品肥效的回收.并对今后磷回收、回用工作的开展,提出了建议.