Processing of Phosphate Mine Tailings by Coagulation Flocculation to Reduce Marine Pollution in Togo: Laboratory Tests

Abstract  About 2.5 million t of sedimentary phosphorite mine tailings, highly enriched with trace metals such as Cd, Cr, Cu, Ni, and Zn, are dumped annually in the coastal waters of Togo without any pre-treatment, causing serious pollution problems in the region. We conducted laboratory jar tests of a coagulation-flocculation procedure with coagulants RM45U and AN945MPM to clarify the sludge. The efficiency of the method depends particularly on two factors: the amount of coagulant and the solid concentration of the sludge to be treated. Thus, with a mud concentration of 47.7 g/L, the average optimal amount of the two coagulants was 25 mg/L. With both coagulants, water turbidity passed from 60 x 103 NTU to approximately 3 NTU after clarification with the optimal amount of the two coagulants. RM45U reduced concentrations of Pb by 40%, Zn by 98.8%, Fe by 80.6%, and Cd by 32.8%. AN945MPM reduced Pb by 20%, Zn by 98.5%, Fe by 48%, and Cd by 32.8%.     

混凝法处理朝阳新华钼矿尾矿水的研究

朝阳新华钼矿尾矿水中的细粒悬浮物在大量水玻璃作用下长期悬浮,回用时严重影响选矿指标。本文以H2SO4和CaO为pH调整剂,以PAC、PAFCS和PAM为絮凝剂,以MgCl2和CaCl2为助凝剂,研究了用不同混凝剂处理时废水的浊度以及絮体的沉降速度。试验结果表明,以CaO为pH调整剂、PAM为絮凝剂、CaCl2为助凝剂,用量分别为600g/t、20g/t、200 g/t时,絮体沉降最快,上清液浊度仅为7.62FTU。     

改性煤矸石作为废水处理吸附剂的试验研究

利用改性煤矸石处理味精精馏段生产废水。试验结果表明,在原水pH=1.8,COD 770 mg/L,NH3-N217 mg/L,浊度29 NTU时,投加120目改性煤矸石1 g,与50 mL废水混合,振荡吸附120 min,处理后出水COD为232.46 mg/L,氨氮为78.84 mg/L,浊度为8.5 NTU,对COD、氨氮、浊度的去除率分别可达到69.81%,63.67%,70.73%。该项研究为改性煤矸石作为水处理吸附剂在味精生产废水及其他高浓度氨氮废水处理中的应用提供了理论依据,同时也为味精废水的处理提供了一种途径。     

Acute and Chronic Toxicity of Acid Mine Drainage to the Activated Sludge Process

The combined treatment of acid mine drainage (AMD) and municipal wastewater using the activated sludge process is an innovative approach to AMD remediation. The toxicity of synthetic AMD to activated sludge was evaluated using oxygen uptake rate (OUR) inhibition tests, which showed that activated sludge can withstand high proportions of AMD (EC₅₀ 19?C52% AMD by volume). The EC₅₀ values of municipal and industrial activated sludges were significantly different (p?<?0.05), with municipal sludges exhibiting higher tolerance to AMD. Although the EC₅₀ values for heterotrophic and nitrifying activated sludges were not statistically significantly different, the EC₅₀ values for heterotrophic bacteria were generally higher. Laboratory-based sequencing batch reactors were used to examine the treatability of AMD. Increased concentrations of COD and suspended solids, associated with turbidity and poor floc morphology, were observed in the final effluent after extended AMD loading. Protozoan community structure changed during the AMD loading period, and overall abundance tended to decrease over time. OUR decreased in the AMD-loaded reactors, particularly in the reactor receiving the highest AMD load, indicating reduced biomass activity over the acclimatization period. Results from OUR inhibition tests on the acclimatized activated sludge indicated that over a relatively short timescale (21?days), the activated sludge microbial community can adapt to AMD sufficiently so that shock loads of metals and acidity do not significantly inhibit OUR. These preliminary studies indicate that it is possible to treat AMD successfully in admixture with municipal wastewater using the activated sludge process.     

Decolorizing dye wastewater from the agate industry with Fenton oxidation process

The aim of this work was to investigate the efficiency of Fenton’s reaction in the treatment of the effluents generated by the agate industry. Experiments with different dosages of Fenton’s reagents (H₂O₂ and FeSO₄) were carried out and the treated wastewater quality was analysed in terms of colour, turbidity, suspended solids, COD, surface tension, and sludge generation. Results showed that 2 mL L⁻¹ of H₂O₂ (32–36.5%) and 0.16 g L⁻¹ of FeSO₄ dosages are enough to completely decolourise the effluent, remove suspended solids, reduce the organic content and increase the surface tension. Optimised Fenton’s conditions were used to investigate by GC–MS the organic products remaining in the degradation process. The analysis of the mass spectrum of the compounds present in the wastewater after degradation by the Fenton’s process showed the presence of xylene, linear and branched hydrocarbons, phenolic compounds, and nitrogenated phenol as residual compounds. Thus Fenton’s reaction may be used as a potential chemical oxidant for the treatment of dye organic effluents.     

4种磁性絮凝剂的制备及性能考察

在超声波分散作用下,用聚丙烯酰胺和壳聚糖对d₅₀=1 μm的分析纯四氧化三铁和d₅₀=20 μm的磁铁矿精矿进行改性,制得聚丙烯酰胺-四氧化三铁、聚丙烯酰胺-磁铁矿、壳聚糖-四氧化三铁和壳聚糖-磁铁矿4种磁性絮凝剂。对4种磁性絮凝剂进行XRD、FTIR和SEM分析,发现聚丙烯酰胺能够通过键合作用在两种磁性物表面形成一层较厚的针状物,而壳聚糖对两种磁性物的改性结果不理想。用4种磁性絮凝剂处理马鞍山城市生活污水和巢湖河蓝藻水,结果表明,聚丙烯酰胺-四氧化三铁磁性絮凝剂和聚丙烯酰胺-磁铁矿磁性絮凝剂对污物、蓝藻的去除率分别高达98.13%、99.61%和93.75%、99.02%,但壳聚糖-四氧化三铁磁性絮凝剂和壳聚糖-磁铁矿磁性絮凝剂所获相应去除率分别只有67.50%、35.29%和49.38%、31.57%。由于聚丙烯酰胺-磁铁矿磁性絮凝剂可取得良好的水处理效果且具有实际应用意义,因此认为应对其进行进一步的深入研究。     

CaO-PAM在鲕状赤铁矿浮选废水处理中的混凝作用

鄂西高磷鲕状赤铁矿采用细磨-反浮选工艺可有效提铁降杂,实现铁的回收利用.但该工艺产生的废水浊度高,成分复杂,浮选废水回用困难.本研究对该反浮选废水进行了研究,发现废水pH值为9.6,散射浊度为95 780 NTU,悬浮物浓度为1 272 mg/L.采用氧化钙(CaO)与聚丙烯酰胺(PAM)联用混凝沉淀法处理该废水,用量...     

Characterization and Toxicity Assessment of Wastewater from Rock Phosphate Processing in Tunisia

Phosphate ore processing wastewater (WWPP) from the Gafsa phosphate region of Tunisia was characterized. The WWPP had a very high turbidity, an almost neutral or slightly alkaline pH, and high salinity. The average chemical and biochemical oxygen demands (COD and BOD) met wastewater discharge standards, but the COD/BOD5 (4.34) significantly exceeded biodegradability values. Total nitrogen, residual phosphorus, and some others chemical constituents exceeded wastewater discharge standards. Microbiological enumeration showed that the effluents were very low in microflora. Untreated WWPP and diluted (WWPP/4) inhibited bioluminescence of Vibrio fischeri by 76 and 45%, respectively. The WWPP had a phytotoxicity rate of 20–70%, respectively, for alfalfa and tomato seeds. Adding the effluent to soil for 60 days reduced the residual phytotoxicity of the WWPP-irrigated soil to about 15 and 34%, respectively, for tomato and alfalfa seeds.     

Characterizing hydrocyclone performance for grit removal from wastewater treatment activated sludge plants

Typically, 15–45% of the mixed liquor (sludge) in biological wastewater treatment plants (WWTPs) consists of inorganic (fixed) suspended solids. A portion of these inorganic compounds is grit (sand) originating from the influent. Grit accumulation impacts WWTP design and operating costs as these unbiodegradable solids reduce the effective treatment capacity of the bioreactor and other unit operations that must be sized to carry this material.The goal of this study was to characterize the performance of a hydrocyclone to selectively separate grit from activated sludge. Laboratory experiments were conducted with a 13 mm diameter Krebs hydrocyclone treating sludge from eight WWTPs. Reduced efficiencies of 17 ± 7% on fixed suspended solids and 9 ± 6% on volatile suspended solids were obtained. Grade efficiency curves enabled the development of a modified definition for cut size useful for this application. The characterization of hydrocyclone performance for grit removal from activated sludge will enable modelling of the process for integration into wastewater treatment simulators used for process performance prediction and design.     

化学混凝法处理选矿废水的实验研究

采用混凝法处理广西河池某锡矿废水,探讨了该废水处理的最佳混凝剂和最佳的混凝条件。结果表明,FeCl3·6H2O(FC)是最佳混凝剂,在pH=8.0时,每300mL的废水中投加0.40mL质量分数为5%的FeCl3·6H2O后,再投加0.20mL质量分数为0.1%聚丙烯酰胺(PAM)是处理该废水的最佳用量,废水经处理后浊度从2700NTU降到2.0NTU以下。     

Assessment of Rheological Properties of Bazhenov Formation by Thermobaric Test Data

The performed thermobaric tests of cylindrical bazhenite specimens consisted in recording of time variation in height of the specimens, h(t), under constant axial loading at varied temperature T. The authors demonstrate that under rapid increase/decrease in T deformation process obeys the thermoelastic law and calculate the coefficient of linear temperature expansion. Under constant increased temperature, the process of deformation is described using the viscoelastic Voigt model. The authors formulate and solve inverse problems on elastic moduli and viscosity of rocks by the data of h(t).     

高悬浮物矿井水电化学特性分析及污染物去除效果研究

为了解决宝日希勒露天矿矿井水中浊度偏高的问题,通过对其矿井出水进行电化学特性分析,测得其悬浮物颗粒粒径主要分布在0.6~0.8 μm内,Zeta电位为-23~-25 mV,需选用带正电荷的混凝剂使其沉降。在此基础上优化了“聚合氯化铝(PAC)+聚丙烯酰胺(PAM)”联合处理工艺,研究结果表明：选用30 mg/L PAC+0.5 mg/L PAM联合投加混凝剂的方式,出水浊度最低,可以达到10.8 NTU,浊度去除率达到95.5%;单独投加混凝剂条件下,PAC及聚合氯化铝铁(PAFC)对于水中浊度去除效果优于聚合硫酸铁(PFS),但对于水体化学需氧量(COD_cr)的去除效果不及PFS,且投加3种混凝剂皆不能有效地降低水体总硬度。     

驱油破乳剂在焦化废水处理中的应用

在焦化废水处理生产中,利用季铵盐、阳离子聚丙烯酰胺、聚硅氧烷乳液复配而成的驱油破乳剂,能有效降低废水中的油、NH₃-N、CODcr、悬浮物及浊度,不同组成配比和投加量,去除率有较大差异。实验研究结果表明:驱油破乳剂按600 mL/m³（废水）投加,油去除率可达到75.45%、CODcr去除率可达到56.24%,NH₃-N去除率可达到54.55%,悬浮物去除率可达到80.86%,浊度可降至51.23 mg/L,在生产现场使用得到了验证。驱油破乳剂投加浓度达到800 mL/m³（废水）时,去除时间大大缩短。     

Improving Mine Water Quality by Low Density Sludge Storage in Flooded Underground Workings

This paper discusses the chemical and physical characteristics of low density sludge (LDS) and its interaction with mine water in a flooded German underground fluorite mine. The highly hydrous nature of the sludge (11.5–17 % solids), its rather low sedimentation rate, and its thixotropic viscosity were confirmed. The interaction of LDS and mine water was tested in the laboratory in batch experiments and modelled with PHREEQC. Mine water quality improved through contact with the LDS sludge: the total alkalinity and pH of the water increased and its iron concentration and total acidity decreased. Storage of sludge in a flooded mine could be a sustainable tool for both the handling of LDS and improvement of mine water quality, even when the LDS represents less than 1 % of the total mine water volume. No polymer flocculants from the LDS treatment plant were found in the discharged mine water.     

复合絮凝剂在四氧化三锰工业污水处理中的应用

研究了用聚合氯化铝和聚丙烯酰胺复合絮凝剂处理四氧化三锰工业污水,考察了絮凝剂PAC加入量、助凝剂PAM加入量和加入时间对四氧化三锰工业污水絮凝效果的影响。试验结果表明：实验室过程中,在PAC加入量5 mg/L,PAM加入量0.6 mg/L,PAM在PAC加入后30 s加入条件下,复合絮凝剂的絮凝效果最好,浊度去除率可达94.8%,达到了工业污水排放的国家标准。还对复合絮凝剂在工业污水处理应用中应注意的问题进行了简要分析。     

Treatment of a Jordanian Phosphate Mine Wastewater by Hybrid Dissolved Air Flotation and Nanofiltration

Approximately 10,000?m3/day of untreated wastewater is produced during phosphate beneficiation at Eshydia phosphate mine in southern Jordan. The effluent contains 21?wt% phosphates (P₂O₅) and 12–14?wt% solids. Dissolved air flotation (DAF) and subsequent nanofiltration (NF) were investigated as potential treatment methods. DAF combined with the use of a commercial flocculant effectively removed the suspended solids and decreased total dissolved solids (TDS) by 50?%; NF effectively treated the DAF effluent and produced water with only 860?ppm TDS. The treated water can be recycled for use by Eshydia phosphate mine or for irrigation.     

PBS混凝剂处理造纸综合废水

研究了用酸浸的粉煤灰和鼓风炉铁泥作原料制备PBS混凝剂并用于造纸废水的处理结果表明．PBS混凝剂与聚硅酸铝（PSA）絮凝剂配合处理造纸废水．在pH值为7．0、混凝剂的投加量为60mg／L的条件下，SS、CODcr和色度的去除率分别为92．4％．85．2％和91．6％与Al2（SO4）3和FeCl3常规混凝剂相比．PBS混凝剂的混凝沉降性能明显优于常规混凝剂。     

Changes in Efficiency and Hydraulic Parameters During the Passive Treatment of Ferriferous Acid Mine Drainage in Biochemical Reactors

The objective of this study was to evaluate the effects of different reactive mixtures and hydraulic retention times (HRTs) on hydraulic parameters (hydraulic conductivity, k_sat, and porosity) and the efficiency of passive biochemical reactors (PBRs) for treatment of ferriferous acid mine drainage (AMD). Five 10.7 L PBRs were filled with three reactive mixtures, containing either a carbon-rich substrate (60% w/w) or an inert/neutralizing agent (50% w/w). The PBRs were tested over a 450 day period using two qualities of iron-rich AMD (4 and 1 g L^?1 Fe in AMD1 and AMD2, respectively), and two HRTs, of 5 and 7 days. During the last week of the columns’ operation, a tracer test (5 g L^?1 of NaCl) was also performed, in addition to monthly measurements using the falling head method. Changes in HRT and k_sat were evaluated throughout the experiment. The PBRs increased the pH of AMD influents from 3.5 to 6 and efficiently removed Al, Cd, Cr, Ni, Pb, and Zn (>?90%), whereas Fe was only partially and inconsistently treated. No significant differences were observed among the three tested mixtures, regardless of the HRT or the AMD quality. Results from the tracer test and k_sat measurements showed no significant decrease in the initial values of the hydraulic parameters with time except for column 3, where a slight decrease was observed. Although sorption could have been important during the start-up of the PBRs, post-testing characterization of the spent reactive mixtures showed that the Fe was mainly retained as oxy-hydroxides and sulfides. Given the PBRs’ marginal effectiveness for Fe-rich AMD, pre-treatment removal of the iron is recommended.     

黄金工业高盐度废水的处理研究

通过超滤装置的预处理,除去高盐度废水中的胶体和悬浮物。然后通过一级纳滤装置将 进行浓缩,浓缩液通过冷冻系统将K₂SO₄进行回收;一级纳滤装置出水经过二级纳滤装置处理后,出水回用到生产车间,二级纳滤装置的浓缩液重新回到超滤装置。高盐度废水经过处理后,其中的K₂SO₄得到了回收,废水基本达到零排放,可以实现良好的经济效益和社会效益。     

用浮选捕收剂处理电解铜废水的试验研究

电解铜废水主要含有Cu₂ 、Pb₂ 、Zn₂ 、Cd₂ 、Ni₂ 等离子,对人类健康和环境危害很大。因此,对电解铜废水进行处理方法的研究十分必要。本文研究用浮选捕集剂乙基黄药处理电解铜废水。研究结果表明：在调节该废水pH = 6.6的条件下,乙基黄药(10%)投加量20.0 mL/L,快搅时间1.5 min,慢搅时间10 min时Cu₂ 、Pb₂ 、Zn₂ 、Cd₂ 、Ni₂ 的去除率均可达到95%,处理后废水中重金属残留浓度均达到了国家污水综合排放标准(GB8978-2002)的允许排放浓度或一级标准。对重金属螯合物进行的稳定性研究指出,在pH = 9时,乙基黄药的重金属螯合物中Cu₂ 、Pb₂ 、Zn₂ 的泄漏量均为0 mg/g,Cd₂ 的泄漏量为0.8?10_-3 mg/g,Ni₂ 的泄漏量为14.2?10_-3 mg/g,处理后的污泥稳定性好,对环境无二次污染。浮选捕收剂乙基黄药具有pH应用范围广、操作简单、处理成本低、效果稳定等优点,在重金属废水治理中具有良好的应用前景。