重金属杂质对磷酸铵镁结晶法处理制药废水的影响

磷酸铵镁沉淀法处理废水时常受众多因素影响，其中重金属类杂质对该过程影响较大。实验研究了Mn²⁺、Cu²⁺杂质存在条件下，用该法去除制药废水中PO₄^3-、NH₄⁺污染物，同时，用XRD、XRF、SEM等手段研究了所得鸟粪石晶体特征。结果表明，pH为9.5时，Mn²⁺、Cu²⁺杂质存在条件下，PO₄^3-去除率分别为88%和85%，投加晶种有利于回收特定晶形鸟粪石，Cu²⁺对磷酸铵镁结晶过程的影响较Mn²⁺存在时显著。     

pH值控制MAP法脱氮进程的可行性研究

MAP沉淀法处理高NH₃-N废水，操作简便，处理效果好。本试验以NH₃-N浓度为1 000 mg/L的模拟废水为研究对象，研究结果表明，在Mg²⁺∶PO^3-₄∶NH⁺₄=1.2∶1.2∶1（摩尔比）、NaOH投加量为675 g/L的条件下NH₃-N去除率高达98%以上。试验选择出水pH作为控制反应进程的参数，并建立了出水pH与NH₃-N去除率之间的关系。通过调整NaOH投加量控制出水pH在7.5～8之间时，NH₃-N去除率最高，可达98%以上。X-衍射图谱及定量分析表明，沉淀物中MAP的纯度较高，具有一定的回收价值。     

MAP热分解产物的氨氮吸附性能研究

以TG-DTA、XRD、SEM等手段研究了MAP的热分解行为，并对热分解产物的氨氮吸附性能进行了研究。结果表明，热分解MAP可将水和氨释放出来，热分解产物粒径变小，结晶度降低，其XRD图谱主要出现MgHPO₄·3H₂O的特征衍射峰，但在吸附氨氮后，则主要出现MgNH₄PO₄·6H₂O的特征衍射峰；控制MAP在100℃条件下热分解3 h再用于氨氮的处理药剂是合适的，氨氮吸附反应体系的pH值以10较为适宜，在此条件下反应40 min对氨氮的去除率即达90%。     

污泥回流分离工艺（RSSP）除磷脱氮试验研究

介绍了一种新型的脱氮除磷工艺——回流污泥分离工艺（return sludge separate process），及其运行情况。该工艺在传统的厌氧缺氧好氧（A²/O）的模式下，针对硝酸盐对厌氧释磷的抑制问题进行改进，提出回流污泥的气浮浓缩分离方案，以提高系统的脱氮除磷效果。研究结果表明，在进水COD为250～400 mg/L，NH⁺₄-N为30～45 mg/L，PO^3-₄-P为8～10 mg/L左右时，该工艺对NH⁺₄-N和PO^3-₄-P的去除率分别可达79.3%和95%。该系统与A²/O的平行比较数据表明，该系统能够提高氮磷综合处理效率，解决A²/O处理工艺中存在无效释磷和硝酸根抑制问题。     

响应面分析法优化稀土废水MAP沉淀法脱氮

经过预处理后的稀土生产废水，其氨氮浓度大幅降低，但并未达到中华人民共和国《稀土工业污染物排放标准》（GB26451-2011）中氨氮浓度限值。实验通过响应面分析法中的Box-Behnken实验设计（BBD），取pH、n（Mg）：n（N）、n（P）：n（N）3因素，采用Design-Expert 8.0.6，建立合适的剩余氨氮浓度及剩余总磷浓度模型，得到回归方程，并分析模型各项指标，各因素及其相互作用对剩余氨氮浓度及剩余总磷浓度的影响。利用预测模型预测最佳实验条件，在最佳实验条件下验证预测结果，并对沉淀物进行X射线衍射（XRD）分析。结果显示，二次响应模型适用于剩余氨氮浓度及剩余总磷浓度，2个模型均拥有较好的拟合程度、可信度及精密度，最优反应条件为：pH=9.88、n（Mg）：n（N）=1.50：1、n（P）：n（N）=1.38：1时，剩余氨氮浓度为46.58 mg/L，剩余总磷浓度为7.85 mg/L。在最优条件下所得到的沉淀物并非纯净的MgNH₄PO₄·6H₂O，还有Mg₃（PO₄）₂·22H₂O生成。     

黄菖蒲和狭叶香蒲根系对氮磷的吸收动力学

采用改进的常规耗竭法，研究了黄菖蒲（Iris pseudacorus L.）和狭叶香蒲（Typha angustifolia L.）根系对NH₄⁺、NO₃^-和H₂PO₄^-的吸收特征及差异。结果表明，这2种植物根系对NH₄⁺、NO₃^-和H₂PO₄^-的吸收动力学特征均可采用Michaelis-Menten方程描述。2种植物根系对NH₄⁺、NO₃^-和H₂PO₄^-的亲和力（Km）和最大吸收速率（Vmax）有显著差异。吸收H₂PO₄^-时，黄菖蒲根系具有较高的Vmax值和较低的Km值，说明黄菖蒲具有嗜磷特性，并能够适应广范围浓度的H₂PO₄^-环境，适宜用于污染水体磷的去除；吸收NO₃^-时，狭叶香蒲根系具有较高的Vmax值和较低的Km值，表明狭叶香蒲可用于广范围浓度NO₃^-污染的水体修复；吸收NH₄⁺时，黄菖蒲根系具有较低的Vmax值和Km值，而狭叶香蒲根系具有较高的Vmax值和Km值，说明黄菖蒲适宜用于NH₄⁺污染较轻水体的修复，而在NH₄⁺污染较重水体中宜选用狭叶香蒲作为先锋植物。     

鸟粪石结晶法去除垃圾渗滤液中NH_4~+-N的效果研究

研究了鸟粪石结晶法对经混凝预处理后的垃圾渗滤液中NH4+-N的去除效果,考察了不同影响因素对NH4+-N去除效果的影响,并进行了磷酸铵镁(MgNH4PO4·6H2O,简称MAP)沉淀的表征及成分分析,并提出了反应后溶液中Mg2+、PO43-及MAP的回收利用办法。结果表明,反应的最佳条件为:pH8.5～9.5,Mg2+∶NH4+∶PO34-(摩尔比)=1.1∶1.0∶1.3,反应温度30℃,反应时间为25 min时,此时NH4+-N的去除率达94.70%;最佳沉淀剂投加组合为MgCl2.6 H2O与Na2HPO4·12H2O;pH为9.0时生成的沉淀符合典型MAP沉淀的晶体结构,生成的沉淀大部分为MAP,且没有氰化物、酚等有害物质的检出,而pH为10.5时生成的沉淀由许多疏松的微小沉淀颗粒组成,排列较杂乱,影响了沉淀的纯度。利用鸟粪石结晶法去除混凝预处理后的垃圾渗滤液中NH4+-N技术可行,经济效益合理,具有广阔的应用前景。     

UASB反应器厌氧氨氧化菌的脱氮特性研究

研究UASB厌氧氨氧化（ANAMMOX）反应器运行情况，采用普通城市污水厂活性污泥接种，人工合成废水，pH值在7.4～7.8之间，温度控制在(32±1)℃。在反应器稳定运行270～450 d之间的180 d中，对NH⁺₄-N和NO^-₂-N去除率均达到99.9％以上，总氮去除率保持在90％以上，NO^-₃-N产生量在20～30 mg/L之间波动。研究表明,UASB厌氧氨氧化反应器处理废水效果明显，对NH⁺₄-N、NO^-₂-N和TN去除率高，NO^-₂-N和NH⁺₄-N比值可以指示厌氧氨氧化反应器性能的演变。UASB反应器稳定运行阶段容积负荷的影响较小，ANAMMOX菌对合成废水适应性强，反应器抗冲击能力较强，受冲击后恢复迅速。出水pH值稳定在8.5附近，pH值变化情况可作为反应器运行状况的指示。关键词硝化厌氧氨氧化上流式厌氧污泥床生物脱氮     

好氧与厌氧氨氧化复合颗粒污泥完全自营养脱氮影响因素

采用间歇实验，考察了初始NH⁺₄-N浓度、DO浓度和pH对颗粒污泥完全自营养脱氮的特性的影响。研究表明，在完全自营养脱氮系统中，当DO为0.6～0.8 mg/L，pH控制在7.5～7.8时，好氧氨氧化和厌氧氨氧化速率在一定范围内随NH⁺₄-N浓度（30～150 mg/L）的增加而增加，较高的氨氮浓度能提高自营养脱氮反应速率。较高的DO有利于提高亚硝酸盐氧化速率，但会导致亚硝酸盐的积累；DO浓度过低时，好氧氨氧化过程受到抑制。NH⁺₄浓度为36 mg/L，DO控制在0.6～0.8 mg/L的条件下，当pH值为7.8时，完全自营养脱氮的效果最佳，总氮去除速率达最大值为23.976 mg/(g MLSS·d)。     

利用13X沸石分子筛净化含NH+4-N废水的实验研究

研究了13X沸石分子筛在静态和动态条件下对中低浓度含NH⁺₄-N废水的吸附性能，包括影响吸附的主要因素、沸石对NH⁺₄-N的吸附效果和沸石的再生等。静态实验结果表明，pH值为6.5～7.5，吸附时间35 min，吸附温度20～30℃的条件下，沸石对50 mL NH⁺₄-N初始浓度（C0）为80 mg/L的废水吸附效果最佳，吸附过程符合Langmuir型吸附等温式，饱和吸附量为8.61 mg/g。动态条件下，随水力停留时间增加，沸石对NH⁺₄-N的吸附量上升，最大饱和吸附量可达24.20 mg/g，吸附过程符合Thomas吸附模型。直接焙烧法对吸附后的沸石进行再生活化处理效果良好。实验证明，利用13X沸石净化中低浓度含NH⁺₄-N废水具有良好的工业化应用前景。     

磷酸铵镁沉淀法预处理垃圾渗滤液

探讨了用磷酸铵镁沉淀法预处理垃圾渗滤液时,沉淀剂种类、pH值、物质摩尔配比和反应时间等因素对氨氮去除效果的影响。得出了处理氨氮浓度为2 677.34 mg/L的垃圾渗滤液时,在兼顾所用镁盐量尽量低和处理出水氨氮或磷酸盐的残留量都比较低的较佳实验条件为:沉淀剂种类为:MgSO4.7H2O和Na2HPO4.12H2O,反应时间为20 min,pH=9.5,n(Mg)∶n(P)∶n(N)=1.3∶1.15∶1.0。在较佳实验条件下,垃圾渗滤液的NH3-N去除率为97.05%,处理出水PO34--P含量为8.35 mg/L,NH3-N含量为75.86 mg/L。对所得沉淀物进行了成分分析和X-衍射光谱、扫描电镜表征,表明大部分沉淀物为磷酸铵镁物质。     

Overcoming challenges to struvite recovery from anaerobically digested dairy manure

Recovering struvite from dairy manure has consistently posed problems for researchers. This study separated solids from anaerobically digested dairy manure using a filtration system. Filtrate was rich in free magnesium (160 to 423 mg/L), ammonium (320 to 1800 mg N/L) and orthophosphate (93 to 332 mg P/L). High concentrations of free calcium (128 to 361 mg/L) and alkalinity (3309 to 6567 mg/L as CaCO3), however, may hinder struvite precipitation. Batch precipitation tests were conducted to identify and overcome factors that interfere with struvite formation. Precipitation tests at pH 9 identified calcium and ionic strength as most probable interferences. Calcium addition did not significantly change phosphorus removal efficiency, but decreased struvite purity because of formation of calcium phosphates when Ca:P activity ratio was greater than 0.5 to 1. Batch tests demonstrated effective calcium removal from anaerobically digested dairy manure through precipitation of calcium carbonate at pH 9 to 10 while retaining magnesium and orthophosphate, lessening hindrance to struvite formation.     

Coagulation and precipitation as post-treatment of anaerobically treated primary municipal wastewater.

The main objective of this study was to investigate the feasibility of coagulation as a post-treatment method of anaerobically treated primary municipal wastewater. Both mesophilic and ambient (20 degrees C) temperature conditions were investigated in a laboratory-scale upflow anaerobic sludge bed (UASB) reactor. In addition, optimization of the coagulant, both in terms of type and dose, was performed. Finally, phosphorus removal by means of aluminum and iron coagulation and phosphorus and ammonia nitrogen removal by means of struvite precipitation were studied. Anaerobic treatment of primary effluent at low hydraulic retention times (less than 15 hours) resulted in mean chemical oxygen demand (COD) removals ranging from 50 to 70%, while, based on the filtered treated effluent, the mean removals increased to 65 to 80%. Alum coagulation of the UASB effluent gave suspended solids removals ranging from approximately 35 to 65%. Turbidity removal reached up to 80%. Remaining COD values after coagulation and settling were below 100 mg/L, while remaining total organic carbon (TOC) levels were below 50 mg/L. Filterable COD levels were generally below 60 mg/L, while filterable TOC levels were below 40 mg/L. All coagulants tested, including prepolymerized aluminum and iron coagulants, demonstrated similar efficiency compared with alum for the removal of suspended solids, COD, and TOC. Regarding struvite precipitation, optimal conditions for phosphorus and nitrogen removal were pH 10 and molar ratio of magnesium: ammonia-nitrogen: phosphate-phosphorus close to the stoichiometric ratio (1:1:1). During struvite precipitation, removal of suspended solids reached 40%, while turbidity removal reached values up to 80%. The removal of COD was approximately 30 to 35%; yet, when removal of organic matter was based on the treated filterable COD, the removal increased to approximately 65%. In addition, nitrogen was removed by approximately 70%, while phosphorus removal ranged between approximately 30 and 45% on the basis of the initial phosphorus concentration. Finally, size fractionation of the organic matter (COD) showed that the various treatment methods were capable of removing different fractions of the organic matter.     

Removal of nitrogen and phosphate from wastewater by addition of bittern

Removal of nitrogen and phosphate through crystallization of struvite (MgNH(4)PO(4).6H(2)O) has gained increasing interest. Since wastewaters tend to be low in magnesium relative to ammonia and phosphates, addition of this mineral is usually required to effect the struvite crystallization process. The present study evaluated the feasibility of using bittern, a byproduct of salt manufacture, as a low-cost source of magnesium ions. High reaction rates were observed; the extent of nitrogen and phosphorus removals did not change beyond 10 min. Phosphorus removals from pure solutions with bittern added were equivalent to those obtained with MgCl(2) or seawater. Nitrogen removals with bittern were somewhat lower than with the alternate Mg(2+) sources, however. Application of bittern to biologically treated wastewater from a swine farm achieved high phosphate removal, but ammonia removals were limited by imbalance in the nitrogen:phosphorus ratio.     

沸石曝气生物滤池预处理微污染水源水中氨氮的研究

利用沸石曝气生物滤池预处理微污染水源水中的氨氮,研究了沸石的静态吸附性能以及不同运行参数对处理效果的影响.结果表明:(1)沸石具有快速吸附,缓慢平衡的特点.采用氨氮质量浓度为5.00 mg/L的使用溶液进行静态吸附实验,当吸附时间为30 min时,氨氮质量浓度为0.66 mg/L,去除率为86.8%,之后氨氮浓度和去除率基本保持不变.(2)水力负荷对氨氮的去除率影响不大,随着水力负荷的升高,氨氮去除率总体呈小幅度下降趋势.当水力负荷由0.4 m~3/(m~2·h)提高到1.3m~3/(m~2·h)时,氨氮平均去除率降低了13.2%.(3)在实验范围内,随着气水比的增大,氨氮平均去除率略有上升.当气水比为0.5(体积比,下同)、1.0、1.5时,氨氮平均去除率分别为81.8%、85.3%、86.7%.(4)氨氮去除主要发生在填料层200～600 mm处,600mm处的氨氮去除率已经达到89.7%,占总去除率的96.9%,而600 mm处后的氨氮浓度趋于平缓,去除率变化很小.     

生物活性炭填料反应器处理含盐水体的硝化性能

以颗粒活性炭为填料,采用盐度梯度两步驯化法构建含盐水体生物滤器硝化功能,研究了生物滤器稳定后水力停留时间(hydraulic retention time,HRT)、进水氨氮负荷和CODMn/N等对反应器硝化性能的影响。结果表明,25～27℃,盐度30的含盐水体生物滤器硝化功能构建需73 d,其中淡水生物滤器硝化功能构建需28 d,淡水驯化为盐度15的生物滤器需19 d,盐度15驯化为盐度30的生物滤器需26 d;实验条件下生物活性炭填料反应器中生物量达到146～742.1 nmolP/g-BAC;调节进水氨氮浓度2 mg/L左右时,最佳HRT为1 h,氨氮去除率达到84.98%,相应的氨氧化菌和硝酸菌氧吸收速率(oxygen uptake rate,OUR)分别为2.091和1.948 mg O2/(g-BAC.h);HRT为1 h时,随着进水氨氮负荷的加大,氨氮去除率逐渐降低,当进水氨氮负荷由0.12增加到0.48 g-N/(kg-BAC.d)时,氨氮去除率由84.98%降低到41.68%,同时氨氧化菌OUR由2.091降低到0.625 mg O2/(g-BAC.h);随着CODMn/N的升高,氨氮去除率下降,CODMn/N从1～8时,氨氮去除率由84.98%降低到53.64%,CODMn去除率却逐渐增加,由40.86%增加到93.59%,异养菌OUR随着CODMn/N升高呈上升趋势,最大达到0.914 mg O2/(g-BAC.h)。     

异养硝化细菌Alcaligenes sp.S3除氮特性及动力学

从湘江生活污水排污口分离纯化的一株菌Alcaligenes sp.S3,在氨氮浓度为400 mg/L时,经过192 h的降解,氨氮的去除率达到88%,并且NH2OH和NO2--N并没出现积累。在对不同浓度的氨氮进行一级动力学拟合时发现,只有氨氮浓度较高时才很好地符合,浓度为500 mg/L时R2达到0.9923。酸性环境对Alcaligenes sp.S3生长有抑制作用,在pH7.5～10生长较好。摇床转速对Alcaligenes sp.S3除氮影响不大,C/N过低或过高对Alcaligenes sp.S3除氮都有影响。     

The Effects of Magnesium and Ammonium Additions on Phosphate Recovery from Greenhouse Wastewater

Phosphorus recovery from greenhouse wastewater, using precipitation-crystallization, was conducted under three levels of calcium concentration, 304 mg/L (7.6 mmol/L), 384 mg/L (9.6 mmol/L), and 480 mg/L (12 mmol/L), and also with additions of ammonium and magnesium into the wastewater. Jar test results confirmed high phosphate removal, with more than 90% of the removal achieved with a pH as low as 7.7. Under the low calcium concentration, ammonium addition affected the chemical reactions at pH lower than 8.0, where struvite was produced; when the pH was raised to 8.8, other calcium compounds dominated the precipitation. Under the medium calcium concentration, ammonium and magnesium addition helped struvite precipitation in the low pH range. Hydroxyapatite (HAP) was the main product. Under the high calcium concentration, ammonium addition showed no effects on the precipitation.     

The effects of magnesium and ammonium additions on phosphate recovery from greenhouse wastewater

Phosphorus recovery from greenhouse wastewater, using precipitation-crystallization, was conducted under three levels of calcium concentration, 304 mg/L (7.6 mmol/L), 384 mg/L (9.6 mmol/L), and 480 mg/L (12 mmol/L), and also with additions of ammonium and magnesium into the wastewater. Jar test results confirmed high phosphate removal, with more than 90% of the removal achieved with a pH as low as 7.7. Under the low calcium concentration, ammonium addition affected the chemical reactions at pH lower than 8.0, where struvite was produced; when the pH was raised to 8.8, other calcium compounds dominated the precipitation. Under the medium calcium concentration, ammonium and magnesium addition helped struvite precipitation in the low pH range. Hydroxyapatite (HAP) was the main product. Under the high calcium concentration, ammonium addition showed no effects on the precipitation.