氧化-混凝法处理含砷选矿废水的试验研究

以某钨矿含砷选矿废水为处理对象,针对常规铁盐混凝工艺除砷的不足,提出采用氧化-铁盐混凝法。氧化剂选用双氧水和次氯酸钠,研究探讨了两种氧化剂对混凝沉淀法除砷效果的影响。结果表明,当铁盐除砷的工艺条件:pH值7.55左右,三氯化铁投加量453.33 mg·L-1(Fe/As摩尔比=3.0),混凝反应时间25 min,PAM投加量40 mg·L-1固定时,双氧水氧化反应阶段的最佳工艺条件为:pH值5.50~7.50,氧化时间25 min,双氧水投加量950 mg·L-1,选矿含砷废水经该预氧化工艺处理后,再由铁盐沉淀法处理,出水砷浓度降至0.302 mg·L-1,砷去除率达到99.28%;次氯酸钠氧化反应阶段的最佳工艺条件为:pH值6.00~8.00,氧化时间25 min,次氯酸钠投加量1500 mg·L-1,选矿含砷废水经该预氧化工艺处理后,再由铁盐沉淀法处理,出水砷浓度为0.437 mg·L-1,砷去除率可达到99.0%。经比较分析得出双氧水为最佳氧化剂。     

黄金矿山含氰废水深度处理工艺研究及应用

黄金矿山含氰废水污染物种类多，处理难度大，采用“MVR—氯碱深度破氰—反渗透”联合工艺对浮选废水、混合废水2种废水进行中试试验，并进行了工业应用。结果表明：采用该工艺可实现废水中铜、铅、砷、汞等的达标去除，总氰化合物降至0.1 mg/L左右，COD降至40 mg/L以下，氨氮降至2 mg/L以下；直接处理成本较低，仅为57.90元/m³。项目的成功实施，形成了一套完整的黄金矿山含氰废水处理工艺，且成本低，推广应用前景广阔。     

硫化法处理含砷废水的响应曲面优化研究

山东某冶炼企业产生的含砷废水As含量为20 251.6 mg/L,本文采用硫化沉砷工艺进行条件试验探索较佳工艺参数,并采用响应曲面法进行优化。试验对硫化剂用量、反应时间和搅拌速度对沉砷的影响进行了研究,得出较佳的工艺参数为硫化剂用量n(S^2-)/n(As)=1.2、反应时间30 min、搅拌速度80 r/min,此条件下沉砷后液含砷0.24 mg/L;采用曲面响应法对硫化剂用量、反应时间和搅拌速度进行显著性和交互作用分析,得到的二次回归模型显著,且拟合度较好;各因素对废水沉砷的影响次序为反应时间影响>硫化剂用量>搅拌时间;响应曲面预测最佳工艺参数为硫化剂用量n(S^2-)/n(As)=1.22、反应时间38 min、搅拌速度64 r/min,此条件下,沉砷后液含砷浓度平均值为0.15 mg/L。实践结果表明,采用优化后的硫化沉砷工艺参数进行处理,沉砷后液含砷浓度小于0.2 mg/L,加石灰调节后,符合山东省地方标准DB 37/3416.5—2018(《流域水污染物综合排放标准》第5部分：半岛流域)要求的外排标准。     

无机盐改性麦糟在低浓度含砷水中的吸附性能研究

含砷废水的排放已成为国内外饮用水源最大的安全隐患之一.采用无机盐改性麦糟作为吸附剂,对低浓度含砷水进行吸附试验研究.确定最佳改性条件为1.5 mol/L NaCl 与麦糟按1 L∶100 g 混合均匀,室温下改性12 h.在不调节pH 值（溶液pH 值为7）,改性麦糟投加量5 g/L 条件下,初始浓度为0.1 mg/L 的含砷水可在60 min 达到吸附平衡,且最终使出水满足《生活饮用水卫生标准》（GB5749-2006）中砷含量（0.01 mg/L）要求.考察了溶液共存阴离子对改性麦糟吸附含砷水的影响,并验证了NaCl 改性麦糟处理含砷水源地水的效果.      

电催化氧化法去除黄金冶炼废水中氰化物和氨氮试验研究

对黄金冶炼废水进行了电催化氧化处理研究,考察了氯离子质量浓度、极板间距、电流密度等因素对氰化物和氨氮去除效果的影响。最佳工艺参数为:废水初始pH值9.28、氯离子初始质量浓度25 g/L、极板间距20 mm、电流密度16.3 mA/cm2、废水循环流速64 mL/min。在最佳工艺条件下,电解150 min,氰化物质量浓度从28.84 mg/L降至0.20 mg/L,氨氮质量浓度从700 mg/L降至7 mg/L,去除率分别为99.3%、99.0%,处理后废水中的总氰、氨氮均可达到《GB 8978—1996污水综合排放标准》一级标准。     

聚合硫酸铁处理含锑砷地下渗水试验研究

本实验研究了聚合硫酸铁(PFS)对北区地下渗水含锑砷废水的处理效果,探讨了不同铁盐除锑砷效果对照、PFS用量对除锑砷效果的影响、不同碱中和的影响、铁渣中锑砷杂质在水溶液的返溶试验。结果表明,通过PFS的混凝作用,协同沉淀的吸附作用,可以有效的对含锑砷废水进行处理,处理过程简单,一步到位。小试中,在常温时,PFS用量0.6‰,处理时间30min,pH=7的条件下,废水中锑浓度可以降至0.30mg/L以下,砷浓度降至0.10mg/L以下,达到了《锡锑汞工业污染物排放标准》(GB30770-2014)中相关排放限值。     

氧化-铁盐混凝沉淀法处理钨冶炼含砷废水的试验研究

钨冶炼生产实践中遇到的主要问题之一就是含砷废水的处理。研究采用氧化-铁盐混凝沉淀工艺处理赣南某钨冶炼废水。试验研究了氧化剂种类、氧化剂用量、铁盐种类、铁盐用量、p H值对砷去除效果的影响。结果表明:"双氧水+水合硫酸亚铁"除砷效果较好,当双氧水用量0.44 m L/L,氧化反应时间5~10 min,水合硫酸亚铁投入量1.48 g/L,混凝反应p H=9~10时,废水中砷的去除率达到99.0%,反应过后残留砷的浓度降至0.49 mg/L,达到《污水综合排放标准》(GB8978—1996)一级标准。     

含砷含铁冶金废水Fenton氧化脱砷处理

采用Fenton预氧化-中和脱砷法对含砷含铁冶金废水进行净化处理,通过单因素试验分别研究了Fenton氧化剂用量、氧化时间对铁氧化率的影响,以及中和脱砷过程药剂用量、反应时间、搅拌速度和反应温度对脱砷效果的影响,并对最优条件的脱砷后液和中和渣与企业工艺参数进行对比。结果表明：向废水中加入5 mL/L过氧化氢(30%)预氧化5 min后,废水中Fe²⁺浓度从2.23 g/L降至0.01 g/L,Fe²⁺氧化率为99.55%。最优脱砷条件为：石灰加入量15 g/L、搅拌速率300 r/min、温度30℃、反应时间50 min,脱砷率为99.9%。中和渣毒性浸出试验结果为0.32 mg/L,满足危险废物浸出毒性鉴别标准(GB 5085.3—2007),实现砷无害化处理。     

微波改性麦糟处理低浓度含砷水试验研究

重金属废水排放不仅造成资源浪费,而且已成为饮用水源最大的安全隐患之一,其治理一直是世界环保领域的重大课题.为了顺应我国新的《生活饮用水卫生标准》(GB5749-2006),即将《生活饮用水卫生标准》(GB5749-85)中砷标准从0.05 mg/L降低到0.01 mg/L,本课题选择废麦糟作为生物吸附剂的原料,以工业废水中具有代表性的阴离子砷(Ⅲ)为处理对象,采用微波改性麦糟作为吸附剂,对低浓度含砷水进行试验研究.确定最佳改性条件为低火强度下改性7 min.在pH值为9,微波改性麦糟投加量10 g/L条件下,初始浓度为0.5 mg/L 的含砷水可在35 min达到吸附平衡,最高去除率达到99.4%.微波改性麦糟对砷的吸附动力学行为符合准二级方程.     

含砷选矿废水治理研究及处理方案探讨

文章通过平江黄金洞矿业有限责任公司所产生含砷废水的特性研究,确定采用石灰破乳沉淀、絮凝沉降后再通过酸反调的工艺处理该选矿废水,处理水中的主要污染物pH＜9,悬浮物SS＜100mg/L,As含量＜0.5 mg/L,实现废水达标排放.     

化学沉淀—折点氯化法处理稀土氨氮废水

采用化学沉淀—折点氯化法去除稀土氨氮废水中的氨氮。化学沉淀试验表明,调节废水pH=7,沉淀时间15min,废水中氨氮的去除率可达90.64%;折点氯化试验表明,调节废水pH=7,次氯酸钠溶液加入量为理论量的1.4倍,反应时间15min,废水中氨氮浓度可降至8.35mg/L,处理后的废水满足稀土工业废水氨氮排放标准,并且本工艺是经济可行的。     

高铁酸盐对焦化废水中COD、NH_3-N的处理效果的研究

高铁酸盐加入量对COD和NH3-N去除效果的实验结果表明:在常温下,当高铁酸盐的加入量为14mg/L时,焦化废水中COD的质量浓度由320mg/L下降到88mg/L,去除率达72.5%;NH3-N质量浓度由68mg/L下降到14.9mg/L,去除率达78.1%。     

Friedreich's ataxia: point mutations and clinical presentation of compound heterozygotes

The effects of ammonium nitrate, ammonium chloride, ammonium sulfate, and sodium nitrate on survival and growth of Pacific treefrog (Pseudacris regilla) and African clawed frog (Xenopus laevis) embryos were determined in static-renewal tests. The 10-day LC50s for the three ammonium compounds for P. regilla ranged from 25.0-32. 4 mg/L NH4 -N. The 10-day sodium nitrate LC50 for P. regilla was 578. 0 mg/L NO3-N. LC50s for X. laevis exposed for 4 or 5 days to the three ammonium compounds ranged from 27.5-60.2 mg/L NH4-N. The sodium nitrate LC50 for X. laevis ranged from 438.4-871.6 mg/L NO3-N. The lowest LOAEL based on length or weight was 6.1 mg/L NH4-N for the two species. The lowest LOAELs for NO3-N were 111.1 mg/L for P. regilla and 56.7 mg/L for X. laevis. Calculated unionized NH3 comprised 0.5-1.8% of measured NH4-N concentrations. Potential harm to amphibian populations could occur if NH4-N and NO3-N in agricultural runoff or drainage impacts sensitive life stages for a sufficiently long period.     

Nitrification∕Denitrification in Intermittent Aeration Process for Swine Wastewater Treatment

A continuous-flow intermittent aeration (IA) process has been studied for nitrogen removal from anaerobically digested swine wastewater with high ammonium content. High nitrogen removal efficiency of average 91% total Kjeldahl nitrogen and 92% NH4-N was achieved in an IA system with an alteration of 1-h aeration and 1-h nonaeration. Nitrification and denitrification were found to be responsible for the nitrogen removal in the system. Nitrite and nitrate in the effluent were less than 1.0 mg∕L and 8.0 mg∕L, respectively. The specific nitrification and denitrification rates of the single-sludge IA culture were determined through batch experiments as 2.79–3.70 mgNO3-N∕g volatile suspended solids-h and 0.59–1.03 mgNO3-N∕g volatile suspended solids-h, respectively. In the IA process, the aeration period created favorable conditions for nitrifying bacteria (dissolved oxygen = 4–6 mg∕L and oxidation-reduction potential = 80–100 mV), while the nonaeration period provided good environment for denitrifying bacteria (dissolved oxygen < 1 mg∕L and oxidation-reduction potential as low as 0 mV). Ammonia volatilization in the IA process was negligible (<0.008%). Denitrification activity in the IA process prevented nitrate from accumulation and significant pH change in the system, which is critical for nitrogen removal from swine wastewater with high ammonium content.     

钢铁企业的焦化废水短程生物脱氮的研究

铁碳电池预处理－厌氧－好氧－缺氧多级SBR法处理焦化废水取得了良好的COD、氨氮脱除效果。在SBR反应器中创造条件，既保证了亚硝化反应的顺利进行，同时又保证了生成的亚硝酸盐与NH4^＋及有机物发生反应实现共同降解，亚硝酸盐与NH4^ 的反应弥补了反亚硝化过程中碳源的不足。系统运行稳定，氨氮浓度大于600mg/L时，却除率大于95％。该方法成本低，处理效果较好。     

基于生石灰强化处理的锰渣无害化技术

以酸浸锰渣为对象,生石灰为添加剂,翻转浸出法提取锰渣浸出液,分析了浸出液中的污染物类型及浓度,研究了生石灰添加量、锰渣含水率、预反应时间等对锰渣无害化处理的影响及最优条件。结果表明,锰渣中的主要污染物为锰和氨氮,且浓度严重超标。生石灰的水化反应形成了良好的碱性环境,以物理包裹、吸附及沉淀作用,起到了很好的无害化处理效果。最优的处理条件为:生石灰添加量10%、锰渣含水率27%、预搅拌时间40 min、预静置时间72h,锰渣浸出液中可溶性锰浓度为2.60mg/L,锰脱除率达99.8%,NH_4~+-N浓度为19.53mg/L,脱除率为97.0%。     

Effect of Dynamic Loading on Biological Nutrient Removal in a Pilot-Scale Liquid-Solid Circulating Fluidized Bed Bioreactor

A pilot-scale liquid-solid circulating fluidized bed (LSCFB) bioreactor was employed for biological nutrient removal from municipal wastewater at the Adelaide Pollution Control Plant, London, Ontario, Canada. Lava rock particles of 600?μm were used as a biomass carrier media. The system generated effluent characterized by <1.0?mg NH4–N/L, <6.0?mg NO3–N/L, <1.0?mg PO4–P/L, <10?mg TN/L, and <10?mg SBOD/L at an influent flow of 5?m3/d, without adding any chemicals for phosphorus removal and secondary clarification for suspended solids removal. The impact of the dynamic loading on the LSCFB effluent quality and its nutrient removal efficiencies were monitored by simulating wet weather condition at a maximum peaking factor of 3 for 4 h. The achievability of effluent characteristics of 1.1 mg NH4–N/L, 4.6 mg NO3–N/L, 37 mg COD/L, and 0.5 mg PO4–P/L after 24 h of the dynamic loading emphasize the favorable response of the LSCFB to the dynamic loadings and the sustainability of performance without loss of nutrient removal capacity.     

Nitrogen and phosphorus removal for swine wastewater by ammonium crystallization and intermittent aeration process

A process on crystallized precipitation of ammonium by adding magnesium salt and phosphate was carried out to improve C/N ratio in swine wastewater. After completion of crystallized precipitation of ammonium, an intermittent aeration process with aeration and nonaeration periods alternated at interval of 1:1 hr day-1 is used for the improved swine wastewater (T-N/BOD = 0.14: BOD = 8200 mg/liter and T-N = 1166 mg/liter). The results obtained from the experiment show that the removal ratios of T-N and NH4-N are 91% and 99%, respectively. T-P is not removed, while the removal ratio of PO4-P is 60% as 3% of CaCl2 liquid is added. The results also indicate that dilution with water is effective to improve the removal of phosphorus even if raw swine wastewater contains high concentrations of T-N, T-P, BOD, and TOC.     

含氨氮有机物和重金属离子的废水处理试验与设计

通过对某科技园含高氨氮、有机物、重金属离子废水的现场试验,确定了该类型工业废水处理工艺流程。采用两段吹脱NH3-N;两级重金属絮凝沉淀回收金属Co^2＋、Ni^2＋;缺氧、好氧组合生化、生物滤池、沸石过滤器处理工艺。处理后出水COD、NH3-N浓度分别小于100和15mg／L;重金属Co^2＋、Ni^2＋离子浓度均小于1mg／L。     

Simultaneous Nitrogen and Phosphorus Removal from High-Strength Industrial Wastewater Using Aerobic Granular Sludge

Aerobic granular sludge technology was applied to the simultaneous nitrogen and phosphorus removal from livestock wastewater that contains high concentrations of nitrogen and phosphorus (TN: 650?mg/L; TP: 125?mg/L). A lab-scale sequencing batch reactor was operated in an alternating anaerobic/oxic/anoxic denitrification mode. Granular sludge was first formed using synthetic wastewater. When livestock wastewater was diluted with tap water, the shape and settleability of aerobic granular sludge were maintained even though livestock wastewater contained suspended solids. Simultaneous nitrification, denitrification, and phosphate uptake were observed under an aerobic condition. However, when nondiluted livestock wastewater was used, the diameter of granular sludge and the denitrification efficiency under an oxic condition decreased. When the concentrations of nitrogen and phosphorus in wastewater increased, hydraulic retention time (HRT) increased resulting in a decrease in selection pressure for granular sludge. Therefore, the sustainment of granular sludge was difficult in livestock wastewater treatment. However, by applying a new excess sludge discharge method based on Stokes’ law, the shape of granular sludge was maintained in spite of the long HRT (7.5?days). To select large granular sludge particles, excess sludge was discharged from the upper part of settled sludge because small particles localized there after settling. Finally, excellent nitrogen and phosphorus removal was accomplished in practical livestock wastewater treatment. The effluent concentrations of NH4–N, NOx–N, and PO4–P were <0.1, 1.4, and 1.2?mg/L, respectively.