Characteristics of high-sulfate wastewater treatment by two-phase anaerobic digestion process with Jet-loop anaerobic fluidized bed

A new anaerobic reactor, Jet-loop anaerobic fluidized bed （JLAFB）, was designed for treating high-sulfate wastewater. The treatment characteristics, including the effect of influent COD/SO42 ratio and alkalinity and sulfide inhibition in reactors, were discussed for a JLAFB and a general anaerobic fiuidized bed （AFB） reactor used as sulfate-reducing phase and methane-producing phase, respectively, in two-phase anaerobic digestion process. The formation of granules in the two reactors was also examined. The results indicated that COD and sulfate removal had different demand of influent COD/SO4^2- ratios. When total COD removal was up to 85%, the ratio was only required up to 1.2, whereas, total sulfate removal up to 95% required it exceeding 3.0. The alkalinity in the two reactors increased linearly with the growth of influent alkalinity. Moreover, the change of influent alkalinity had no significant effect on pH and volatile fatty acids （VFA） in the two reactors. Influent alkalinity kept at 400-500 mg/L could meet the requirement of the treating process. The JLAFB reactor had great advantage in avoiding sulfide and free-H2S accumulation and toxicity inhibition on microorganisms. When sulfate loading rate was up to 8. 1 kg/（m^3.d）, the sulfide and free-H2S concentrations in JLAFB reactor were 58.6 and 49.7 mg/L, respectively. Furthermore, the granules, with offwhite color, ellipse shape and diameters of 1.0-3.0 mm, could be developed in JLAFB reactor. In granules, different groups of bacteria were distributed in different layers, and some inorganic metal compounds such as Fe, Ca, Mg etc. were found.

Treatment of simulated wastewater from in situ leaching uranium mining by zerovalent iron and sulfate reducing bacteria

Batch and column experiments were conducted to determine whether zerovalent iron (ZVI) and sulfate reducing bacteria (SRB) can function synergistically and accelerate pollutant removal. Batch experiments suggest that combining ZVI with SRB can enhance the removal of U(Ⅵ) synergistically. The removal rate of U(Ⅵ) in the ZVI+SRB combining system is obviously higher than the total rate of ZVI system and SRB system with a difference of 13.4% at t=2 h and 29.9% at t=4 h. Column experiments indicate that the reactor filled with both ZVI and SRB biofilms is of better performance than the SRB bioreactor in wastewater basification, desulfurization and U(Ⅵ) fixation. The results imply that the ZVI+SRB permeable reactive barrier may be a promising method for treating subsurface uranium contamination.

Effect of sulfate on the methanogenic activity of a bacterial culture from a brewery wastewater during glucose degradation

The maximum specific methanogenic activity （SMA） of a sludge originating from a brewery wastewater treatment plant on the degradation of glucose was investigated at various levels of sulfate on a specific loading basis. Batch experiments were conducted in serum bottles at pH 7 and 35℃. A comparison of the values indicates that the SMA of this mixed culture was increased and reached its highest level of 0.128 g CH4 gas COD/（g VSS.d） when biomass was in contact with sulfate at a ratio of 1：0.114 by weight.

Recovery of copper sulfate after treating As-containing wastewater by precipitation method

The solid sodium hydroxide neutralized acidic As-containing wastewater till pH value was 6. Green copper arsenite was prepared after copper sulfate was added into the neutralized wastewater when the molar ratio of Cu to As was 2：1 and pH value of the neutralized wastewater was adjusted to 8.0 by sodium hydroxide. The arsenious acid solution and red residue were produced after copper arsenite mixed with water according to the ratio of liquid to solid of 4：1 and copper arsenite was reduced by SO2 at 60℃ for 1 h. The white powder was gained after the arsenious acid solution was evaporated and cooled. Copper sulfate solution was obtained after the red residue was leached by H2SO4 solution under the action of air. The results show that red residue is Cu3（SO3）2·2H2O and the white powder is As2O3. The leaching rate of Cu reaches 99.00% when the leaching time is 1.5 h, molar ratio of H2SO4 to Cu is 1.70, H2SO4 concentration is 24% and the leaching temperature is 80 ℃. The direct recovery rate of copper sulfate is 79.11% and the content of CuSOa·5H2O is up to 98.33% in the product after evaporating and cooling the copper sulfate solution.

Preparation and Application of Polymer Silicate Phosphate Ferric Sulfate Used in High-Viscosity Oil Refining Wastewater Treatment

A new kind of flocculants, named Polymer Silicate Phosphate Ferric Sulfate(PSPFS), was synthesized by ferrous sulfate used as the main material and activated silicic acid as additive. In this paper, High-Viscosity Oil Refining wastewater from Liaohe Petrochemical Corporation was the treatment object. Overall, the in-fluencing factors and synthesis technology conditions of PSPFS were determined by experiments. First of all, the conditions of influencing factors were showed as follows: the mass percent concentration of ferrous sulfate 55%,concentration of sodium silicate 15% , the molar ratio of ferrous sulfate and hydrogen peroxide 1.2:1, oxidation temperature 40 degree Celsius, oxidation time 4 hours, polymerization temperature 60 de-gree Celsius and polymerization time 2 hours. Secondly, the optimal ratios of components were determined by uniform design method. The molar ratio of Fe/Si is 5.0:1, Fe/H2SO4 is 3.2:1, and Fe/P is 18.0:1. At last, the optimal experimental condition was determined as follows: the dosing quantity 200mg/L, pH value 5.5~9, temperature 25~45℃, stirring time 2 min, and standing time 3 min, according to the result of floc-culation experiments with PSPFS. Besides, the result of the comparative experiments showed that the effi-ciency of PSPFS was much better than the reference flocculants.

Biological treatment of wastewater with high concentrations of zinc and sulfate ions from zinc pyrithione synthesis

An enriched and domesticated bacteria consortium of sulfate-reducing bacteria(SRB)was used to treat wastewater from zinc pyrithione(ZPT)production,and the effects of different reaction parameters on sulfate reduction and zinc precipitation were evaluated.The single-factor experimental results showed that the removal rates of Zn2+and24SO?decreased with an increased ZPT concentration ranging from3.0to5.0mg/L.Zn2+and24SO?in wastewater were effectively removed under the conditions of30?35°C,pH7?8and an inoculum concentration of10%?25%.The presence of Fe0in the SRB system enhanced Zn2+and24SO?removal and may increase the resistance of SRB to the toxicity of Zn2+and ZPT in wastewater.A Box?Behnken design was used to evaluate the influence of the main operating parameters on the removal rate of24SO?.The optimum parameter values were found to be pH7.45,33.61°C and ZPT concentration of0.62mg/L,and the removal rate of24SO?reached a maximum of91.62%under these optimum conditions.

Treatment of Oily Wastewater Using Composite Flocculant of Polysilicate Ferro-Aluminum Sulfate – Rectorite

In this study, a novel flocculant was prepared by an inorganic polymetric flocculant (IPF) - polysilicate ferro- aluminum sulfate (PSFA) and rectorite (REC). The structure of the PSFA-REC composite was characterized by Fourier transform infrared (FT-IR) spectroscopy and X-ray diffraction (XRD), in order to determine the optimal temperature. The flocculation test was made at 25℃, 45℃ and 65℃, the results indicated that when the temperature was 65℃, the removal efficiency of the oil and COD was the best, which was 87.2% and 92.6% respectively. Then by comparisons among rectorite (REC), PSFA and the composite PSFA-REC at the temperature of 65℃ and the optimal dosage of 11 mg/L, the composite PSFA-REC showed better flocculation performance than flocculant REC and PSFA alone.

Evaluation of the Inverse Fluidized Bed Biological Reactor for Treating High-Strength Industrial Wastewaters

The aim of this work was to investigate the aerobic degradation of high-strength industrial (refinery) wastewaters in the inverse fluidized bed biological reactor, in which polypropylene particles of density 910 kg/m3 were fluidized by an upward flow of gas through a bed. Measurements of chemical oxygen demand (COD) versus residence time t were performed for various ratios of settled bed volume to reactor volume (Vb/VR) and air velocities u. The largest COD reduction, namely, from 54,840 to 2,190 mg/l, i.e. a 96% COD decrease, was achieved when the reactor was operated at the ratio (Vb/VR) = 0.55, air velocity u = 0.046 m/s and t = 65 h. Thus, these values of (Vb/VR), u and t can be considered as the optimal operating parameters for a reactor when used in treatment of high-strength refinery wastewaters. In the treatment operation conducted in a reactor optimally controlled at (Vb/VR) = 0.55, u = 0.046 m/s and t = 65 h, the conversions obtained for all phenolic constituents of the wastewater were larger than 95%. The conversions of about 90% were attained for other hydrocarbons.

Development of Combined Biological Technology for Treatment of High-strength Organic Wastewater and Results of Case Studies

Our study group has developed a unique combined ters from the industries of dyestuff, pharmaceutical, chemical biological technology to treat high-strength organic wastewaengineering and zymolysis by using the principles of anaerobic ecological niche and bio-phase separation. The study obtained five national invention patents and eight patent equipments. This technology contains four kernel processes - two-phase anaerobic-aerobic process, hydrolysis-acidification-oxidation process, UASBAF-oxidation process, and internal cycling-hydrolysis-oxidation process. Fifteen pilot projects were accomplished in the basins of Tai Lake, Huai River, Liao River and Songhua River, and their total capital investment reached 185.214 million Yuan （RMB）. Compared to conventional wastewater treatment technology, the innovative technology is more costeffective for high-strength organic wastewater treatment, can save capital investment by 15% - 30%, lessen land usage by 20% to 40% and decrease the operating cost by 10% to 25%. The operating cost of treatment per cubic meter industrial wastewater could be below 0.6 to 1.4 Yuan （RMB）.

Removing contaminants from tannery wastewater by chemical precipitation using CaO and Ca(OH)2

The removal of Cr,sulfates and Chemical Oxygen Demand(COD)from industrial tannery wastewater by chemical precipitation was carried out using Calcium oxide(CaO)and Calcium hydroxide(Ca(OH)2).Different doses of alkalis,ranging from deficiency to excess hydroxyl species over the stoichiometric necessary,were used to remove theoretically the 100%of Cr[0.3-3.2 g alkali·(g Cr^3+)^-1].The precipitation was carried out at room temperature,10 min of vigorous stirring,200 r·min^-1 and a settling time of 24 h,followed by separation and characterization of liquid product.As result of addition of alkalis,pH underwent increase as did the alkali concentration.The removal of Cr,and sulfates also increased as alkali concentration did,although for first species the changes at higher alkali contents were less evident.COD removal on the other hand,did not follow a unique trend,instead exhibited a maximum.Based on our results,selection of a specific dose of alkali was carried out taking as reference the efficiency on total chromium removal,keeping the pH in the range 7 to 9 to ensure Cr precipitation as chromium hydroxide.With those conditions,jar test was used to produce enough liquid product in order to determine the removal percent of several other species.The removal percent of the species was as follows:Cr,SO4^2-,ZnSO4,FeSO4,CN^-1,NiSO4,Fe2[Fe(CN)6]at 99.8%,66.9%,99.6%,21.4%,70.9%,52.8%and 76.4%with CaO,and 99.8%,61.6%,99.9%,7.1%,84.0%,54.4%and 90.5%with Ca(OH)2,respectively.

Treatment of Sebacic Acid Industrial Wastewater by Extraction Process Using Castor Oil Acid as Extractant

Wastewater containing high concentrations of phenol and sodium sulfate is generated in sebacic acid （SA） industry. Castor oil acid, a raw material for producing SA, can be used to extract phenol from wastewater in order to reduce the amount of phenol used in the process and discharge of phenol. The results show that the extrac- tion mechanism is that hydroxyl group of phenol is linked to carboxyl group of castor oil acid by hydrogen bond. The extraction process approaches equilibrium in 30 min. Extraction ratio increases with the increase of sodium sulfate and castor oil acid, and decreases as phenol increases. When the oil-water ratio is 1 ： 3, the optimal distribu- tion coefficient of 40 is obtained. Phenol saturation concentration in castor oil acid is 1.03 mol.L-1 after extraction for 4 times. The equilibrium constant （Kex） at 25℃ is 8.41 and the endothermic enthalpy （AH） is 1.513 kJ.mo1-1. The Gibbs free energy （AG） is -5.277 kJ. tool-1 and the value of AS is calculated to be 22.3 J. mo1-1. K-1.

Quantification and control of restrictive ecological factors in acidogenic de-sulfate bioreactor

As an artificial microbial ecosystem, acidogenic de sulfate bioreactor has high efficiency of sulfate removal. The restrictive ecological factors, including causing ecological factors, such as COD/SO 4 2- ratio and sulfate loading rate (Ns), and following ecological factors, such as pH value, oxidation reduction potential (ORP) and alkalinity (ALK) have significant effect on the ability and stability of acidogenic de sulfate bio reactor. Continuous flow and batch test were carried out to investigate the quantification and control of COD/SO 4 2- ratio, Ns, pH value, ORP and ALK in acidogenic de sulfate bioreactor supplied with molasses wastewater as sole organic carbon source and sodium sulfate as electron donor. It was demonstrated that In order to maintain high sulfate removal rate (SRR) of 80% to 90%, the restrictive factors should meet all the requirement as follows: k COD/ SO 4 2-  ratio≥2.0, Ns≤7.5 kg (m 3·d) -1 ,pH=5.7～6.2,ORP=-320～-420 mV and  ALK= 1 500～2 000 mg/L.

The Microbial Metabolic Characteristics in the Course of Sulfate-Reduction

Acid-producing phase reactor of two-phase anaerobic treatment process has remarkable advantages treating sulfate-laden wastewater. In order to investigate SRB population's capability of utilizing substrate and the microbial acidification type formed during the course of sulfate reduction, continuous-flow and batch tests were conducted in a continuous stirred tank bio-film reactor supplied with sodium sulfate as electron acceptor. The experimental results demonstrated that the acidification type formed b...

A review of modified and hybrid anaerobic baffled reactors for industrial wastewater treatment

This review discusses high-strength wastewater treatment using anaerobic baffled reactors(ABRs)and modified ABRs.The research findings and applications of ABRs in treating various types of high strength wastewater generated from food companies,livestock,and industries were summarized and reported.Measurement parameters affecting the performance of ABRs are briefly discussed.The state-of-the-art laboratory studies are compiled and critically reviewed.Critical challenges and suggestions for future investigation are also addressed.

改性高岭土处理模拟印染废水效果研究

本文采用煅烧方法活化高岭土,采用聚合硫酸铁处理煅烧活化后的高岭土,通过对比2种高岭土的表征,利用它们处理大红染料模拟印染废水的色度,分析2种高岭土表征对模拟印染废水色度处理效果的相关性。结果表明,聚合硫酸铁改性煅烧活化后的高岭土比煅烧活化高岭土在BET表面积、吸附体积及BJH吸附平均孔径的数据显示更优,而运用聚合硫酸铁改性煅烧活化后的高岭土处理模拟印染废水色度的去除率更高,可高达99.94%。

含硫酸盐废水对磷石膏胶结充填体材料性能的影响

鉴于矿山废水处理工艺具有一定的局限性,且磷石膏充填工艺需要消耗大量的水资源,将矿山含硫酸盐废水作为磷石膏充填用水并探讨其可行性。结果表明:废水中的硫酸盐能够促进磷石膏充填体的早期水化反应,进而提升充填体早期强度。当SO_(4)^(2-)浓度从0增加至30 000 mg/L时,充填体7 d强度由0.46 MPa升高至0.63 MPa,提高了37%;14 d强度由0.64 MPa升高至1.03 MPa,提高了61%。这主要跟水化产物钙矾石(AFt)和水化硅酸钙(C-S-H)的形成有关;但随着养护时间的增长,充填体28,60,90 d强度均在硫酸盐浓度为15 000 mg/L时达到最高。过量的SO_(4)^(2-)会干扰水化硬化过程,充填体后期强度因受到钙矾石的膨胀特性以及Na2SO4重结晶等影响而出现下降。研究结果可为矿山废水治理和磷石膏充填工艺优化提供新思路。

普鲁士蓝类钠电池正极生产废水预处理工艺研究

钠离子电池作为新兴产业,有关其生产工艺的研究较多,但是鲜少见到关于钠电池生产废水处理工艺的研究。因此,本文对普鲁士蓝类钠电池正极废水的预处理工艺进行实验研究,探究最佳处理工艺。最终确定了母液废水采用直接氧化法预处理工艺,即先加入H_(2)O_(2)(1.18倍理论投入量),然后用质量分数为30%的NaOH溶液调pH至9左右,静置30 min,再经过管式超滤膜过滤,母液中铁锰元素的去除率分别约为99.93%和99.99%。洗水废水采用两段式沉淀法预处理工艺,即第一阶段采用固氰除铁法,先用质量分数为30%的NaOH溶液调pH至7左右然后加入硫酸亚铁(硫酸亚铁投入量与废水中铁元素质量比为5.2),反应静置30 min。主要去除废水中绝大部分的铁元素和少部分锰元素。在一段处理的基础上再采用氧化沉淀法,先加入H_(2)O_(2)(0.83倍理论投入量),然后用质量分数为30%的NaOH溶液调pH至9,反应静置30 min,再经过管式超滤膜过滤,最终铁和锰元素的去除率分别约为99.87%和99.99%。为实际工程中钠电池废水预处理提供了重要技术参考。

高盐废水中硫酸铵和硫酸钠的分质结晶工艺研究

处理高盐废水并回收其中的盐资源是许多生产企业废水综合治理的难题。采用等温溶解平衡法测定了10、15、60、80℃下Na_(2)SO_(4)-(NH_(4))_(2)SO_(4)-H_(2)O的液固相平衡数据,基于相平衡数据划分了结晶区域。根据高盐废水的组成和液固相平衡数据,提出了分质结晶分离(NH_(4))_(2)SO4和Na_(2)SO_(4)的工艺路线,设计了结晶过程工艺参数并进行了实验验证。结果表明,废水经3步结晶回收得到的(NH4)2SO4纯度达到了99.2%、Na_(2)SO_(4)纯度达到了98.9%,满足GB/T 535—2020《肥料级硫酸铵》和GB/T 6009—2014《工业无水硫酸钠》的纯度指标要求。该研究可为高盐废水中(NH_(4))_(2)SO_(4)和Na_(2)SO_(4)的回收利用提供参考。

癸炔二醇生产过程中钾盐的回收研究

采用实验室制备的含炔醇的碱液,探究活性炭吸附碱液中有机物的规律及吸附的最佳条件,并回收碱液中的钾离子得到优级纯硫酸钾产品。结果表明,活性炭吸附的最佳条件为:吸附温度为40℃、活性炭用量为2 g/100 mL、pH为5、吸附时间为40 min;pH为5时,溶液中的酯类有色物质会发生分解从而大幅度提高活性炭对有机物的去除率。