Struvite precipitation for ammonia nitrogen removal in 7-aminocephalosporanic acid wastewater

7-Aminocephalosporanic acid wastewater usually contains high concentrations of ammonium (NH??-N), which is known to inhibit nitrification during biological treatment processes. Chemical precipitation is a useful technology to remove ammonium from wastewater. In this paper, the removal of ammonium from 7-aminocephalosporanic acid wastewater was studied. The optimum pH, molar ratio, and various chemical compositions of magnesium ammonium phosphate (MAP) precipitation were investigated. The results indicated that ammonium in 7-aminocephalosporanic acid wastewater could be removed at an optimum pH of 9. The Mg2?:NH??-N:PO? 3?-P molar ratio was readily controlled at a ratio of 1:1:1.1 to both effectively remove ammonium and avoid creating a higher concentration of PO? 3?-P in the effluent. MgCl?·6H?O + 85% H?PO? was the most efficient combination for NH??-N removal. Furthermore, the lowest concentration of the residual PO? 3?-P was obtained with the same combination. Struvite precipitation could be considered an effective technology for the NH??-N removal from the 7-aminocephalosporanic acid wastewater.     

Recovery of ammonia from wastewater through chemical precipitation

Journal of Thermal Analysis and Calorimetry - Chemical precipitation is a consolidated technique applied in wastewater treatment to remove and recover phosphorous and ammonium that remain in the...     

钙型沸石对生活污水中氨氮去除的研究

通过静态方法研究了钙型沸石对氨氮的去除效果．氨氮在钙型沸石上的吸附是吸热过程，饱和吸附容量是46．29mg／g．经过10次吸附-解析-再吸附循环过程，从吸附容量的数据可知盐酸和氯化钠可以获得很好的再生效果，吸附容量的标准偏差分别为6．34％和6．59％．对生活污水中氨氮的去除效果表明，在废水处理过程中钙型沸石将是一种实用和廉价的氨氮吸附剂。     

Ammonium-Nitrogen Recovery from Wastewater by Struvite Crystallization Technology

Struvite crystallization is one of the sustainable approaches for recovering ammonium nitrogen (NH₄-N) from wastewater in the form of a valuable material, in parallel with improving wastewater treatment efficiency. Focusing on NH₄-N recovery, this review discusses the factors influencing struvite crystallization including the effect of foreign elements. It is shown that more than 95% of NH₄-N could be recovered in the form of struvite, a magnesium-ammonium phosphate (MAP) salt, from some kinds of wastewater. This review emphasizes the role of utilizing alternative sources of Mg and P in improving the process sustainability. Additionally, it also explains how the MAP precipitation process could result with significant reduction of other pollutants contributing to total organic carbon, of color and turbidity, which support MAP integration with other treatment methods. The main options of lowering MAP recovery cost are presented; it was shown that applying low-cost materials of both Mg and P could save more than 65% of the process’s cost. Finally, the future research directions to improve NH₄-N recovery are pointed out.     

Nutrient removal and energy production in a urine treatment process using magnesium ammonium phosphate precipitation and a microbial fuel cell technique

Urine pretreatment has attracted increasing interest as it is able to relieve the nitrogen and phosphorus overloading problems in municipal wastewater treatment plants. In this study, an integrated process, which combines magnesium ammonium phosphate (MAP) precipitation with a microbial fuel cell (MFC), is proposed for the recovery of a slow-release fertilizer and electricity from urine. In such a two-step process, both nitrogen and phosphorus are recovered through the MAP process, and organic matters in the urine are converted into electricity in the MFCs. With this integrated process, when the phosphorus recovery is maximized without a dose of PO(4)(3-)-P in the MAP precipitation process, removal efficiencies for PO(4)(3)-P and NH(4)(+)-N of 94.6% and 28.6%, respectively, were achieved with a chemical oxygen demand (COD) of 64.9% accompanied by a power output of 2.6 W m(-3). Whereas removal efficiencies for PO(4)(3)-P and NH(4)(+)-N of 42.6% and 40%, respectively, and a COD of 62.4% and power density of 0.9 W m(-3) were obtained if simultaneous recovery of phosphorus and nitrogen was required through dosing with 620 mg L(-1) of PO(4)(3-)-P in the MAP process. This work provides a new sustainable approach for the efficient and cost-effective treatment of urine with the recovery of energy and resources.     

Removal of aqueous ammonium with magnesium phosphates obtained from the ammonium-elimination of magnesium ammonium phosphate

In order to recycle magnesium ammonium phosphate (MgNH4PO4.6H2O: MAP) obtained from MAP process, which is one of the attractive processes for removal of aqueous ammonium and phosphate from wastewater, ammonium elimination from MAP to magnesium phosphates and ammonium incorporation into the magnesium phosphates have been investigated in the present study. It is confirmed that magnesium hydrogen phosphate (MgHPO4) is favorably obtained from the ammonium elimination from MAP at temperatures greater than 353 K, although magnesium phosphate (Mg3(PO4)2) and magnesium pyrophosphate (Mg2P2O7) have been suggested as possible candidates. Based on the dissolution-precipitation mechanism for the removal of aqueous ammonium with magnesium phosphates, three magnesium phosphates were employed for the removal of aqueous ammonium. The order of the removal rate of the aqueous ammonium was MgHPO4>Mg3(PO4)2>Mg2P2O7, as expected from the solubility of those magnesium phosphates. The removability of the solid obtained from ammonium elimination of MAP is also confirmed. The present results show that MAP can be employed as an advanced material for the removal/recovery of ammonium, although it is generally accepted that an excess of MAP obtained from the wastewater treatment can be only used as a slow-acting fertilizer.     

Modular Functionalization of Metal-Organic Frameworks for Nitrogen Recovery from Fresh Urine**

Nitrogen recovery from wastewater represents a sustainable route to recycle reactive nitrogen (Nr). It can reduce the demand of producing Nr from the energy-extensive Haber-Bosch process and lower the risk of causing eutrophication simultaneously. In this aspect, source-separated fresh urine is an ideal source for nitrogen recovery given its ubiquity and high nitrogen contents. However, current techniques for nitrogen recovery from fresh urine require high energy input and are of low efficiencies because the recovery target, urea, is a challenge to separate. In this work, we developed a novel fresh urine nitrogen recovery treatment process based on modular functionalized metal–organic frameworks (MOFs). Specifically, we employed three distinct modification methods to MOF-808 and developed robust functional materials for urea hydrolysis, ammonium adsorption, and ammonia monitoring. By integrating these functional materials into our newly developed nitrogen recovery treatment process, we achieved an average of 75 % total nitrogen reduction and 45 % nitrogen recovery with a 30-minute treatment of synthetic fresh urine. The nitrogen recovery process developed in this work can serve as a sustainable and efficient nutrient management that is suitable for decentralized wastewater treatment. This work also provides a new perspective of implementing versatile advanced materials for water and wastewater treatment.     

Ammonium and Phosphate Quantification in Wastewater by Using a Voltammetric Electronic Tongue

Ammonia (NH₄? N) and orthophosphate (PO₄? P) quantification in wastewater treatment plants is important due to their implication in the eutrophication process. A voltammetric electronic tongue as a tool for the prediction of ammonia and orthophosphate concentrations from influent and effluent wastewater is proposed herein. An electrochemical study of the response of the ammonium and orthophosphate ions was performed in order to design a suitable waveform for each electrode. Partial Least Squares analysis was used to obtain a correlation between the data from the tongue and the concentrations of ammonia and orthophosphate measured in the laboratory showing good predictive power.     

Fluorination of germanium concentrates with ammonium fluorides

New method for processing of germanium-containing raw materials to obtain germanium oxide was suggested and studied. The method is based on the fluorination of germanium-containing raw materials with ammonium fluorides, followed by a sublimation isolation of ammonium hexafluorogermanate, its dissolution, and precipitation of germanium oxide from solution. The thermodynamics of the process was calculated and its thermogravimetric analysis was made. The kinetics of germanium oxide fluorination by ammonium hydrodifluoride was experimentally studied. A technological scheme for processing of germanium-containing raw materials with ammonium fluoride was suggested.     

Fluorination of beryllium concentrates with ammonium fluorides

New method for processing of beryllium ores to beryllium oxide was suggested and studied. The method is based on decomposition of bertrandite or phenacite with ammonium chloride, with the subsequent leaching of ammonium tetrafluoroberyllate and precipitation from a beryllium hydroxide solution. The thermodynamic characteristics were calculated and a thermogravimetric analysis of the process was made. The kinetics of beryllium oxide fluorination with ammonium fluoride was experimentally studied. A technological scheme of a closed cycle for processing of beryllium-containing raw materials with ammonium fluoride was suggested.     

配位聚合重金属沉淀剂BDP的研究及其应用

使用自制的配位聚合重金属沉淀剂BDP对印制电路板含铜废水进行处理.结果表明,沉淀剂BDP能有效处理废水中自由及络合Cu2+,处理后废水的pH在7.5左右,废水中剩余铜离子降低到0.5 mg/L.该沉淀剂BDP可应用到PCB厂含Cu2+废水处理,使之达到国家废水处理排放标准.     

Optimization of ammonium removal from waste water by natural zeolite using central composite design approach

The aims of the present study are to investigate removal of ammonium ion from wastewater using natural Western Azarbaijan zeolite and to optimize effective parameters by experimental design. In order to remove ammonium ions from aqueous solutions, experiments were carried out using column method as functions of the initial ammonium concentration, flow rate and pH of the solution. The results clearly confirmed that all mentioned parameters have vital affects on removing ammonium ions from wastewater and effluents, so got optimized. Central composite design with response surface methodology was applied for the optimization of main experiment parameters. The significance of the independent variables and their interactions were tested by the analysis of variance ANOVA and f-test statistics. Optimization of the variables for maximum removal efficiency by natural zeolite was performed using the quadratic model. The model predicted maximum removal efficiency under the optimum conditions including initial ammonium concentration of 30?mg?l^?1; flow rate of 1?ml?min^?1 and pH 6, which was very close to the experimental value determined in column experiment. The cation exchange capacity of natural Western Azarbaijan zeolite was found to be 1.79?meq?g^?1. Based on the experimental results, it can be concluded that the natural Western Azarbaijan zeolite has an excellent potential for removing ammonium ions from aqueous solutions and it is suggested as a suitable material for wastewater treatment.     

以氨水和碳酸铵为沉淀剂制备氧化铝的对比研究

γ-Al2O3，是一种常用的催化剂载体，它具有比表面大和价廉易得等优点。但对于很多高温反应体系，如汽车尾气催化净化，其热稳定性在很大程度上影响了汽车尾气净化催化剂的活性和稳定性，因此提高γ-Al2O3的高温热稳定性对保持汽车尾气净化催化剂的反应活性、延长催化剂的使用寿命非常重要。     

Nuclear Magnetic Resonance and X-ray Crystallography to Improve Struvite Determination

Ammonium and phosphate removal from industrial streams is important for many chemical processes, especially wastewater and sewerage treatment. Struvite precipitation is a popular choice and has been well characterized in model systems. However, struvite is a member of a family of similar phosphates of various valences and degrees of hydration. This paper shows that the ammonium phosphate precipitation from complex waste of decaying urine is identical to the product in model and other organic systems, i.e., struvite. We have shown that titration assays are possible for struvite, but they are difficult and hence we have also used nuclear magnetic resonance (NMR) and X-ray crystallography. NMR shows the high purity of struvite. Surprisingly, the crystals from this system are large and generate improved structural determination by X-ray crystallography compared to struvite prepared in solution or discovered in other natural systems. These large crystals allow facile separation of struvite, compared to more conventional methods using fluidized bed reactors which generate irregular concretions with difficulty.     

醇-盐双水相技术去除废水中的酚类物质

A novel method for treatment of phenolic compounds in cokery wastewater by propyl-alcohol ammonium sulfate aqueous two-phase system was investigted.The effects of the amount of ammonium sulfate used,the amount of propyl-alcohol used,pH value on extractield was studied.Extraction was optimized using a L9(34)orthogonal test.The results indicated optimum extraction conditions were the amount of ammonium sulfate used of 18.0 g,the amount of propyl-alcohol used of 16 mL,and pH value of 3.0.A extraction yield of 99.37% was achived under optimum extraction conditions and via secondary extraction.     

处理含铅废水的现状及研究进展

废水中的铅严重危害环境及人体的健康,如何处理含铅废水引起了很多科研人员的重视。本文综述了近年来处理含铅废水的研究进展,详细介绍了吸附法、膜分离法、离子液体萃取法、化学沉淀法、电解法、电絮凝法、微生物絮凝法和植物修复法等处理含铅废水的现状,分析了各种处理方法的优缺点,并展望了未来深度处理含铅废水的发展趋势。     

Removal of ammonium ion from aqueous solutions using natural zeolite: kinetic,equilibrium and thermodynamic studies

The aim of the present study is to investigate the removal of ammonium ions from aqueous solutions using the natural Western Azerbaijan zeolite by utilizing ion exchange process. Batch experimental studies were conducted to evaluate by changing relevant parameters such as pH, dosage of adsorbent, stirring time, initial ammonium concentration, and temperature. The results clearly confirmed that all mentioned parameters have vital affects on removing ammonium ions from wastewater and effluents, so got optimized. Adsorption kinetics and equilibrium data for the removal of ammonium ion were analyzed using Langmuir and Freundlich equations. The Langmuir model fits the equilibrium data better than the Freundlich model. According to the Langmuir equation, the maximum uptake for ammonium ion was 43.47 (mg g^?1). Pseudo-first-order and pseudo-second-order models were used to represent the kinetics of the process. Kinetic studies showed that the adsorption followed a pseudo-second-order reaction. The calculated thermodynamic parameters (ΔG°, ΔH°, and ΔS°) indicate that the adsorption process is feasible, spontaneous, and endothermic at 20–50 °C. Based on the experimental results, it can be suggested that the natural Western Azerbaijan zeolite has the potential of application as an efficient adsorbent for the removal of ammonium ions from aqueous solutions, and is suggested for wastewater treatment purposes.     

PREPARATION OF BAGASSE XANTHATES（BX）AND NICKEL REMOVAL FROM WASTEWATER BY BX

Water-insoluble bagasse xanthates were prepared by xanthation of alkalified celluloses by treating bagasse with chromium hydroxide reaction effluent.The removel of nickel from both test solutions and electroplating industrial wastewater samples with BX was investigated.The process was studied taking into account such parameters as pH of water,precipitation time,xanthate dosage and storage time of BX.These products wrer found to be highly efficient in removing nickel.The residual concentration of nickel after treatment can be reduced to a value of the ordor of 0.01mg·l^-1.     

Application of Natural Clinoptilolite for Ammonium Removal from Sludge Water

Sludge water (SW) arising from the dewatering of anaerobic digested sludge causes high back loads of ammonium, leading to high stress (inhibition of the activity of microorganisms by an oversupply of nitrogen compounds (substrate inhibition)) for wastewater treatment plants (WWTP). On the other hand, ammonium is a valuable resource to substitute ammonia from the energy intensive Haber-Bosch process for fertilizer production. Within this work, it was investigated to what extent and under which conditions Carpathian clinoptilolite powder (CCP 20) can be used to remove ammonium from SW and to recover it. Two different SW, originating from municipal WWTPs were investigated (SW1: c₀ = 967 mg/L NH₄-N, municipal wastewater; SW2: c₀ = 718–927 mg/L NH₄-N, large industrial wastewater share). The highest loading was achieved at 307 K with 16.1 mg/g (SW1) and 15.3 mg/g (SW2) at 295 K. Kinetic studies with different specific dosages (0.05 g_CLI/mg_NH4-N), temperatures (283–307 K) and pre-loaded CCP 20 (0–11.4 mg/g) were conducted. At a higher temperature a higher load was achieved. Already after 30 min contact time, regardless of the sludge water, a high load up to 7.15 mg/g at 307 K was reached, achieving equilibrium after 120 min. Pre-loaded sorbent could be further loaded with ammonium when it was recontacted with the SW.