鸟粪石结晶沉淀法处理氨氮废水的应用研究

论述了鸟粪石的形成机理、形成的影响因素。在废水处理中采用鸟粪石沉淀法脱氮，具有氨氮去除率高、反应速度快、污泥体积小的优点，同时可以回收氨氮。作为缓释肥，具有良好的经济效益。重点介绍了鸟粪石沉淀法处理氨氮废水目前的研究进展，并探讨了该技术在今后的研究趋势。     

Phosphorus recovery from fosfomycin pharmaceutical wastewater by wet air oxidation and phosphate crystallization

Fosfomycin pharmaceutical wastewater contains highly concentrated and refractory antibiotic organic phosphorus (OP) compounds. Wet air oxidation (WAO)-phosphate crystallization process was developed and applied to fosfomycin pharmaceutical wastewater pretreatment and phosphorus recovery. Firstly, WAO was used to transform concentrated and refractory OP substances into inorganic phosphate (IP). At 200 °C, 1.0 MPa and pH 11.2, 99% total OP (TOP) was transformed into IP and 58% COD was reduced. Subsequently, the WAO effluent was subjected to phosphate crystallization process for phosphorus recovery. At Ca/P molar ratio 2.0:1.0 or Mg/N/P molar ratio 1.1:1.0:1.0, 99.9% phosphate removal and recovery were obtained and the recovered products were proven to be hydroxyapatite and struvite, respectively. After WAO-phosphate crystallization, the BOD/COD ratio of the wastewater increased from 0 to more than 0.5, which was suitable for biological treatment. The WAO-phosphate crystallization process was proven to be an effective method for phosphorus recovery and for fosfomycin pharmaceutical wastewater pretreatment.     

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.     

鸟粪石结晶法回收垃圾渗滤液氨氮研究

采用MgSO₄·7H₂O和Na₂HPO₄·12H₂O使NH₃-N生成MgNH₄PO₄·6H₂O（鸟粪石）结晶沉淀法回收渗滤液中NH₃-N。考察了pH值、反应时间、药剂配比对NH₃-N去除率的影响。结果表明,鸟粪石结晶回收NH₃-N反应的适宜pH值为9～9.5之间,过高的pH会破坏鸟粪石晶体结构,导致固定氨从MgNH₄PO₄中游离出来,不利于氨氮的去除。在pH值为9.5、反应时间为25 min、Mg²⁺∶NH⁺₄∶PO^3-₄=1.5∶1∶1.5的最佳条件下,渗滤液中NH₃-N浓度由初始3 500 mg/L,经结晶沉淀后降低至175 mg/L,去除率达95%。鸟粪石结晶沉淀过程中几乎不吸收重金属,同时回收了氨氮,其沉淀产物鸟粪石是一种优良的缓释肥原料。     

工艺条件对鸟粪石法回收磷耗碱量的影响及其理论计算

通过分析磷回收过程中存在的各种耗碱因素,推导出耗碱量的理论计算公式,计算出了不同工艺条件下的理论耗碱量,并与小型连续搅拌反应-沉淀磷回收过程的实验实测值进行比较。结果表明,耗碱量的理论计算值与实验测定值的平均相对误差为13.20%,说明计算方法可用于耗碱量的工程估算;耗碱量随出水pH值的增大而急剧增加,随废水中氨氮含量和磷初始浓度的增加都近似于线性增加,但随镁磷比的增加基本不变。因此,从节约废水处理成本的角度看,磷回收过程中pH值应控制在9.2-9.3,氮磷比控制在3.0-5.0,镁磷比控制在1.1-1.2为佳。磷回收过程的药剂消耗量与废水中磷的浓度和工艺条件有关,以磷初始浓度为124 mg/L,N/Mg/P=5∶1.2∶1,出水pH值为9.20的回收过程为例,处理毎吨废水需消耗片碱0.5313 kg,成本约为1.328元,需消耗氯化镁（含六个结晶水）0.9758 kg,成本约为0.634元。因此,处理每吨废水的药剂成本约为1.962元,其中耗碱约占67.7%。     

Aerobic Treatment of a Nitrogen-Limited Chemical Process Waste water

Abstract

Nitrogen transformations and their effect on aerobic suspended growth treatment of an industrial wastewater were studied in three parallel bench-scale reactors operated at 5 "C at mean cell residence times (MCRT) of 15, 30, and 60 days. In normal process wastewater, the bulk of influent nitrogen was in organic form, and the fraction transformed was almost totally incorporated into synthesized biomass. Assimilative control by heterotrophs maintained ammonianitrogen levels below permitted effluent levels, and nitrification was not significant. Although volatile suspended solids had a nitrogen content of only 5% to 8%, effective organics removal was maintained, and total organic carbon and filtered daily average five-day biochemical oxygen demand (BODS) were below permitted effluent levels. A marked improvement in settleability and lower effluent total suspended solids was achieved by adding ammonia-nitrogen to the wastewater in excess of stoichiometric growth requirements.

During a batch production cycle of a cationic chemical, the ratio of nitrogen to chemical oxygen demand and the fraction of the total influent nitrogen in soluble form increased in the wastewater. Reactor effluent ammonia levels increased to above permit levels at all three MCRTs during treatment of wastewater containing cationic production effluents. The magnitude of ammonia increase was greater for longer MCRTs, suggesting that synthesis of cell mass was not capable of assimilating the increased ammonia supply under these non-steady conditions. The experimental results suggest several potential strategies for operating the aerobic process at the treatment facility, including adding nitrogen to improve settleability and discontinuing these additions when wastewater contains a high ratio of nitrogen to chemical oxygen demand and an elevated soluble nitrogen fraction     

Ammonia removal from pretreated methane fermentation effluent through a soil trench system: a column experiment

In order to find the optimal running conditions and mechanisms of ammonia removal through a soil trench system that is designed for treating pretreated methane fermentation effluent, a soil column whose structure was similar to the soil trench system was prepared, and irrigated with wastewater below 30 °C. At the beginning, ammonia was mainly adsorbed by the soils, and the ammonia adsorption capacity of soils gradually saturated. After the 12th day, nitrification began in the soil column; the ammonia in the soil column decreased sharply, and the nitrite and nitrate peak appeared sequentially as the wastewater application rate decreased from 0.74 to 0.37 l h⁻¹. When the nitrification in the soil column reached a steady-state, 98% of all the ammonia in the influent was transformed into nitrate.

By changing the running conditions such as temperature, aeration, and wastewater application rate, it was found that the ammonia removal efficiency can be improved by aeration and impeded by low temperature. In these three variables, wastewater application rate has much greater affect on the ammonia removal efficiency; a lower wastewater application rate can increase the ammonia removal efficiency substantially because of the longer travel time.     

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。     

铜酞菁生产中的三废综合治理及其资源化探讨

通过某铜酞菁化工生产企业三废治理及其资源化工艺改进的实践，总结出了一套行之有效的利用酸化工艺废酸的资源化新方法，不但从中回收了高价值的铜泥；同时利用废酸吸收生产工艺中的高含氨尾气，生产硫酸铵，达到了以废治废的目的，整个治理工艺符合循环经济的理念。通过该回收工艺的改进，使上述三废不再进入污水处理系统，从而解决了传统铜酞菁生产废水的高酸度、高盐分、高含氨、高难处理的矛盾，使铜酞菁三废处理易于实行。     

剩余污泥水解酸化液磷去除的影响因素研究

城市污水厂剩余污泥水解酸化后可产生高浓度挥发性有机酸(VFAs),其中的乙酸和丙酸是增强生物除磷(EBPR)工艺的有利基质.但水解酸化液中含有大量的磷,如不进行处理就作为碳源回用到污水处理工艺中,势必增加除磷负荷.利用鸟粪石沉淀法可以去除污水中的磷.对城市污水厂剩余污泥水解酸化液形成鸟粪石的影响因素进行了试验研究.结果表明,在最佳工艺条件下,正磷和总磷的去除率分别可达92.5%和83.8%.     

Prevention of struvite scaling in digesters combined with phosphorus removal and recovery--the FIX-Phos process

The fixation of phosphorus (FIX-Phos) combines struvite prevention and phosphorus recovery by the addition of calciumsilicatehydrate (CSH) particles into the anaerobic digester. The CSH fixates phosphorus as calcium phosphate and reduces the phosphorus concentration in the sludge water that allows for control of struvite formation. The phosphorus-containing recovery product can be separated and recovered from the digested sludge. In pilot plant experiments, 21% to 31% of phosphorus contained in digested sludge could be recovered when CSH was added at concentrations of 2 g/L to 3.5 g/L to a mixture of primary sludge and waste activated sludge (WAS) from enhanced biological phosphorus removal. The recovery product contained few heavy metals and a phosphorus content of 18 wt % P2O5, which allows for recycling as fertilizer. The fixation of phosphorus within the digester may increase wastewater sludge dewaterability. The phosphorus recycle stream to the headworks of the wastewater treatment plant is reduced.     

偶氮二异庚腈生产废水处理试验和工程调试

偶氮二异庚腈的生产过程中产生大量的废水,其有机物和氨氮含量高,生化性差.为解决其处理达标问题,采用氨氮吹脱-上流式厌氧污泥床(UASB)-A/O- NaOCl强氧化-接触氧化的组合工艺对其进行了试验研究.结果表明,该工艺对COD、氨氮的去除率分别达到99％、98％以上.并在此试验研究的基础上,投资建设了一个污水处理站,采用氨氮吹脱-UASB-A/O-二级好氧-NaOCl强氧化-接触氧化-气浮池的组合工艺,经过一年多的运行,出水水质稳定,对COD、氨氮的去除率分别为99％、98％以上,出水水质达到《污水综合排放标准》(GB 8978-1996)的一级标准.     

工艺条件对磷回收过程中鸟粪石沉淀颗粒粒径的影响

在鸟粪石沉淀法回收废水中磷的过程中,鸟粪石颗粒的大小将直接影响其沉淀的速率,进而影响鸟粪石的沉淀效果和磷的回收率。本文采用激光粒度分析仪测定鸟粪石的平均粒径,详细考察在小型连续搅拌反应-沉淀磷回收装置中不同的工艺条件下鸟粪石颗粒粒径的变化规律,并结合Stokes公式计算鸟粪石颗粒在废水出口处的沉降速率,为沉淀池的设计提供参考依据。结果表明:鸟粪石的平均粒径在12～25μm之间,沉降速率在5.46×10-5～2.37×10-4m/s之间。随着反应室水力停留时间的延长,鸟粪石颗粒的粒径逐渐增大,当停留时间超过18 min时,颗粒的粒径基本不变;随着沉淀室水力停留时间的延长,鸟粪石颗粒的平均粒径缓慢增大,当停留时间超过70 min后颗粒粒径的变化不大;鸟粪石颗粒的平均粒径在一定程度上受废水中磷初始浓度变化的影响,在磷初始浓度为62～128 mg/L时颗粒的粒径变化不大,当磷浓度为496 mg/L时粒径有较大增加,此时鸟粪石颗粒的沉降速率也大幅度增加;鸟粪石颗粒的平均粒径受pH值的影响不大;随氮磷摩尔比的增大,鸟粪石颗粒的平均粒径略有增加;随镁磷摩尔比的增大,鸟粪石颗粒的平均粒径逐渐减小,沉降速率则有明显的下降。     

Bagasse-assisted bioremediation of ammonia from shrimp farm wastewater.

Development of new economically feasible ecofriendly products from agricultural wastes or byproducts for shrimp farm wastewater treatment is the objective of our continued research. Ammonia is a nitrogenous toxicant, which is commonly found in wastewater from shrimp farms. In the present study, we explored the possibility of the use of simply and inexpensively prepared bagasse products so that this abundant crop byproduct could be used to remove ammonia from shrimp farm wastewater. Bagasse, a natural highly fibrous lignocellulosic byproduct of sugarcane, was converted into five different products. Experimental results have shown that ammonia is efficiently removed from wastewater by four bagasse products with a dose of 1 to 6 g/L within 24 hours. The effect of bagasse products on other water quality parameters and growth kinetics of biofilm bacteria onto bagasse fiber have also been studied. Efficacies of products were compared by using statistical analysis. Products developed from bagasse are useful and economical.     

酸性条件下剩余污泥中Ca2＋和Mg2＋溶出对磷回收的影响

为了在酸性条件下实现剩余污泥中磷的高效回收,对pH=3时剩余污泥水解酸化过程中氨氮、正磷酸盐和钙镁离子的溶出现象以及磷回收进行了研究分析。结果表明：当pH=3时,所溶出的氨氮、镁离子和钙离子与磷酸盐的摩尔比均大于1,能满足采用鸟粪石沉淀法或者羟磷灰石沉淀法回收磷的要求;但所溶出的钙镁离子的摩尔比大于1,会对鸟粪石沉淀法回收磷的顺利进行有较大影响;有无外加镁剂对磷回收率影响不大。采用改型后的镁型强酸性阳离子交换树脂进行离子交换可以得到较高纯度的鸟粪石沉淀产品,通过XRD检测其纯度为95％以上。     

Plackett-Burman法筛选污水中氨氮去除的主要影响因素

结合生产实际运行数据,分析了深圳市某污水处理厂A2O生物处理单元、AB生物处理单元、微絮凝过滤单元和次氯酸钠消毒单元等对氨氮的去除效果,采用基于蒙特卡罗(Monte-Carlo)模拟的概率统计方法对该厂再生水中氨氮符合相应标准的概率(保障率)进行了定量计算。结果表明,氨氮存在较大的超标风险,对此采用Plackett-Burman设计对全流程处理工艺中影响氨氮去除效果的因素进行了研究,筛选出了主要控制因子:混合液回流比、过滤池聚合氯化铝(PAC)投加量和接触池中次氯酸钠投加量,为进一步优化工艺参数提供了重要理论依据和实践基础。     

结晶工艺在废水处理领域的应用与发展

结晶水处理工艺具有占地面积小、不产生污泥、可回收资源等优势,近年在国内外备受关注,随着理论和工艺技术的不断完善,其应用范围逐渐扩大。到目前为止,国外已将结晶水处理工艺成功应用于众多实际工程,但国内对其的研究仍局限于实验室阶段。基于上述原因,本文较全面地综述了结晶工艺在废水处理领域的发展现状,并重点对结晶工艺在磷酸盐、重金属的去除与回收以及工业防垢领域的理论研究和工程应用进展进行讨论,同时探讨了目前结晶工艺存在的几个问题以及下一步的发展方向。     

Biodegradation and toxicity of wastewater from industry producing mineral fibres for thermal insulation

The water chemistry, toxicity, and biodegradation of wastewater from an industry producing mineral fibres for thermal insulation were studied. Values for COD, BOD5, suspended solids, and phenol exceeded permissible values for the wastewater discharged into a nearby river and acute toxicity was also detected. Consequently, the effluent should be treated in a municipal wastewater treatment plant so its ready biodegradability was investigated. We found that the wastewater was readily biodegradable, therefore we assume it can be treated in the wastewater treatment plant as the ratio of the wastewater flow rate and the minimal total inflow into the sewage treatment plant would be one to at least 30.     

Completely autotrophic nitrogen-removal over nitrite in lab-scale constructed wetlands: evidence from a mass balance study

A mass-balance study was carried out to investigate the transformation of nitrogenous pollutants in vertical flow wetlands. Landfill leachate containing low BOD, but a high concentration of ammonia, was treated in four wetland columns under predominately aerobic conditions. Influent total nitrogen in the leachate consisted mainly of ammonia with less than 1% nitrate and nitrite, and negligible organic nitrogen. There was a substantial loss of total nitrogen (52%) in one column, whereas other columns exhibited zero to minor losses (<12%). Net nitrogen loss under study conditions was unexpected. Correlations between pH, nitrite and nitrate concentrations indicated the removal of nitrogen under study conditions did not follow the conventional, simplistic, chemistry of autotrophic nitrification. Through mass-balance analysis, it was found that CANON (Completely Autotrophic Nitrogen-removal Over Nitrite) was responsible for the transformation of nitrogen into gaseous form, thereby causing the loss of nitrogen mass. The results show that CANON can be native to aerobic engineered wetland systems treating wastewater that contains high ammonia and low BOD.     

Reactions of the amine-containing drugs fluoxetine and metoprolol during chlorination and dechlorination processes used in wastewater treatment

The reactivities of the amine-containing pharmaceuticals fluoxetine and metoprolol with hypochlorite were studied using conditions that simulate wastewater disinfection including neutral pH (7.0), a range of reaction times (2–60 min), and a molar excess of hypochlorite relative to the pharmaceutical concentration (5.7 times). The reactions were monitored using liquid chromatography (LC) with several detection modes including ultraviolet absorbance (UV), mass spectrometry (MS), and post-column reaction/reductive electrochemistry (EC) for determining active chlorine products. At levels of 10 μM, both compounds reacted rapidly (<2 min) to form principally N-chloramine products that were stable in aqueous solution for at least 1 h. The reaction was also studied in wastewater, and similar reactivity was noted. These results demonstrate that the cations fluoxetine and metoprolol are likely to be rapidly transformed into neutral N-chloramines during wastewater disinfection. The reactivity of the N-chloramines was also studied with sulfite to simulate dechlorination, which is often employed in wastewater treatment. Both N-chloramines reacted slowly with sulfite. In the pure water dechlorination experiments, it was estimated that 70% and 10% of the peak areas remained after 2 min reaction time for fluoxetine and metoprolol, respectively. At longer reaction times both N-chloramines had been completely reduced by sulfite, and the product of the sulfite reduction reaction was the parent pharmaceutical amine. Since typical dechlorination times in wastewater treatment are on the order of seconds, this suggests the chloramines formed from these two basic drugs might evade dechlorination and be released into the environment. The implications of chloramine release are discussed.