Efficient and rapid capture of uranium(Ⅵ) in wastewater via multiamine modified β-cyclodextrin porous polymer

It is quite important to ensure the safety and sustainable development of nuclear energy for the treatment of radioactive wastewater. To treat radioactive wastewater efficiently and rapidly, two multi-amine β-cyclodextrin polymers(diethylenetriamine β-cyclodextrin polymer(DETA-TFCDP) and triethylenetetramine β-cyclodextrin polymer(TETA-TFCDP)) were prepared and applied to capture uranium. Results exhibited that DETA-TFCDP and TETA-TFCDP displayed the advantages of high adsorption amounts(612.2and 628.2 mg·g-1, respectively) and rapid adsorption rates, which can reach(88 ± 1)% of their equilibrium adsorption amounts in 10 min. Moreover, the adsorbent processes of DETA-TFCDP and TETATFCDP on uranium(Ⅵ) followed the Langmuir model and pseudo-second-order model, stating they were mainly chemisorption and self-endothermic. Besides, TETA-TFCDP also showed excellent selectivity in the presence of seven competing cations and could be effectively reused five times via Na2CO3as the desorption reagent. Meanwhile, X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy illustrated that the enriched multi-amine groups and oxygen-containing functional groups on the surface of TETA-TFCDP were the main active sites for capturing uranium(Ⅵ). Hence, multi-amine β-cyclodextrin polymers are a highly efficient, rapid, and promising adsorbent for capturing uranium(Ⅵ)from radioactive wastewater.

STUDY AND SIMULATION OF AN ACTIVATED SLUDGE TREATMENT FOR METHYL VIOLET WASTE WATER

This paper researched a promising biological treatment of methyl violet waste water by methods of activated sludge.Effects of temperature and pH were studied on this process.Kinetic equation of the substrate biodegradation was investigated in the experimental range.It was studied and simulated that flow within the bubble region of this bioreactor according to the κ ε two fluid equation.Simulation results agree well with experimental data.

Biodrying of municipal solid waste with high water content by combined hydrolytic-aerobic technology

The high water content of municipal solid waste(MSW)will reduce the effciency of mechanical sorting,consequently unfavorable for beneficial utilization.In this study,a combined hydrolytic-aerobic biodrying technology was introduced to remove water from MSW.The total water removals were proved to depend on the ventilation frequency and the temporal span in the hydrolytic stage. The ventilation frequency of 6 times/d was preferable in the hydrolytic stage.The hydrolytic span should not be prolonged more than ...

Researches on the Treatment of Phosphorous Wastewater with Oyster Shells

Based on the analysis of adsorptive features of oyster shells,the researches on the treatment of phosphorous wastewater with oyster shells and the effect of temperature on phosphorus removal were carried out.XRD was used to characterize the crystalline phases,and the main component of oyster shells was shown to be CaCO3.When the pretreatment temperature reached 800 ℃,some CaCO3 decomposed into CaO.As the temperature was further raised,CaO increased gradually.Via SEM testing,the oyster shell was a kind of natural porous materials.The pore wall partially collapsed from 550 to 900 ℃.No obvious porous structure was found at 900 ℃.However,without preheating,the oyster shell phosphorous removal material can not adsorb the phosphorus.Pretreatment made calcium activate,thus greatly increasing the absorption of phosphorus.

Study on the Genetic and Physiological Toxicity of Wastewater from a Pharmaceutical Factory Using Root Tip Micronucleus Technology of Vicia faba

ObjectiveThe aim was to assess genetic and physiological toxicity of wastewater from a pharmaceutical factory using root tip micronucleus technology of Vicia faba. MethodThe pollution of wastewater from a pharmaceutical factory was detected by using root tip micronucleus technology of Vicia faba, and the genetic and physiological toxicity of the wastewater to Vicia faba was assessed. ResultNon-processed wastewater had an extremely high level of biological toxicity; the cells were unable to live with the wastewater at a high concentration; the cells were able to grow with the wastewater at a low concentration, though the micronucleus ratio was extremely high. The processed wastewater had no significant impact on cell growth, but the micronucleus ratio was extremely high, showing that the processed water also had a high pollution index. ConclusionThe research could provide scientific references for the national treatment of wastewater from a pharmaceutical factory.

Microplastics and Wastewater Treatment Plants—A Review

The emission of microplastics into nature poses a threat to aquatic and terrestrial ecosystems. Their penetration of the food chain presents a danger to human health as well. Wastewater treatment plants can be seen as the last barrier between microplastics and the environment. This review focuses on the impact of waste treatment plants in retaining microplastics. Studies show that no wastewater treatment method leads to a complete retention of microplastics, and so wastewater treatment plants themselves are viewed as point sources for the discharge of microplastics into the aquatic environment. Problems associated with the utilization of microplastic loaded sewage sludge are also discussed in the review.

Phase equilibria for the pseudo-ternary system(NaCl+Na2SO4+H2O)of coal gasification wastewater at T=(268.15 to 373.15)K

The pseudo-ternary system(Na Cl + Na_2SO_4+ H_2O) of coal gasification wastewater was studied at T =(268.15 to 373.15) K. The solubility and density of the equilibrium liquid phase were determined by the isothermal solution saturation method. The equilibrium solids were also investigated by the Schreinemaker's method of wet residues and X-ray powder diffraction(XRD). According to the experimental data, the phase diagrams were determined. It was found that there was no significant solubility difference on the Na Cl-rich side between the ternary system(Na Cl + Na_2SO_4+ H_2O) in coal gasification wastewater and in pure water. However, the solubility on the Na_2SO_4-rich side of coal gasification wastewater was apparently higher than that of pure water. The increase in the solubility of Na_2SO_4 was most likely caused by the effects of other impurities apart from Na Cl and Na_2SO_4 in coal gasification wastewater. The measured data and phase equilibrium diagrams can provide fundamental basis for salt recovery in coal gasification wastewater.

The addition of microbes for treating textile wastewater

Some strains and culture of bacteria which are able to decolorize dyes and degrade polyvinyl alcohol(PVA) were isolated and selected. A pilot scale facultative anaerobic-aerobic biological process was applied for treatment of textile wastewater containing dyes and PVA. Activated carbon adsorption was used as a tertiary treatment stage, and residual sludge from clarifier returned to the anaerobic reactor again. The pilot test were carried out with two systems. One was inoculated by acclimated sludge, and the another was adding the mixed culture of dye-decoloring and PVA-degrading bacteria for forming biological films, the latter was observed to be more effective than the former. The test has run normally for ten months with a COD loading of 2.13 kg/m3/day, a BOD5 loading of 0.34 kg/m3/day in anaerobic reactor; a COD loading of 1.71 kg/m3/day, a BOD5 loading 0.44 kg/m3/day in aerobic reactor. The pollutants removal efficiency by adding microbes was about 20% higher than that by acclimated sludge. The average removal efficiency of COD stood about 92%, BOD5 97%, PVA 90% and decolorization 80%. The other parameters of effluent quality are also satisfactory.

Recovery of Caprolactam from Waste Water in Caprolactam Production Using Pulsed-sieve-plate Extraction Column

Recovery of caprolactam from waste water of caprolactam production factory was investigated using benzene as solvent in a small-scale pulsed-sieve-plate column. First, liquid-liquid equilibrium (LLE) data were measured, including water-caprolactam-benzene system at low caprolactam concentrations, and waste water-benzene system. Then, the operating regions and mass transfer of the pulsed-sieve-plate column were measured. Finally, the overall apparent heights of a transfer unit based on continuous phase are correlated in terms of the column operation variables.

Experimental Study of Wastewater Treatment of Reactive Dye by Phys-Chemistry Method

Wastewater, which involves easy-soluble reactive dyes, especially non-degradable dyes, is very difficult to decolor efficiently by normal processes such as coagulation process and biological treatment. The high chromaticity se- riously hinders the reuse of reactive dye waste water. In this paper, a new method by bentonite adsorption and coagulation (PAC) is employed for removing color from synthetic dye waste water which contains reactive red K-2G, K-RN blue, K-GR blue, X-3B red, K-GN orange, KB-3G yellow, K-2BP red, K-RN yellow and K-6G yellow. Bentonite pre- treated by 4% CTMAB and milled to 160 order screen is proven to the best decoloring agent. For a 100 mL reactive red K-2G sample (CODcr 400 mg/L, 25 000 chromaticity color), 0.5 g bentonite pretreated and 2.5 mL PAC is enough to decolor wastewater up to 99.92% and the sediment time is short. Non-degradable dyes such as active red X-3B and K-GN orange are declored completely as well. Raw sewage (low chromaticity color) is decolored completely at a ben-tonite dosage of 0.001g. More researches prove the high practical value of this process.

Recycling water glass from wet reclamation sewage of waste sodium silicate-bonded sand

Wet reclamation of waste sodium silicate-bonded sand produces much alkaline sewage and causes pollution. Recycling water glass from wet reclamation sewage of the waste sodium silicate-bonded sand can solve pollution issues and generate economic benefits. In this work, the wet reclamation sewage was filtered, and the filtrate was causticized with a quicklime powder to produce a lye. The effects of causticization temperature, causticization time, and the amount of quicklime powder on the causticization rate were studied. The lye was used to dissolve the silica in the filtration residue to prepare a sodium silicate solution. The effects of the mass of filtration residue, dissolution temperature, and dissolution time on sodium silicate modulus were studied. Finally, the recycled water glass was obtained by concentrating the sodium silicate solution, and the bonding strength of the recycled water glass was tested. The results showed that the causticization rate could be improved by increasing the amount of quicklime powder, causticization temperature, and causticization time, and the highest causticization rate was above 92%. Amorphous silica in the filtration residue dissolved in the lye. Increasing the amount of the filtration residue, dissolution temperature, and dissolution time could improve the sodium silicate modulus. The bonding strength of the recycled water glass was close to that of commercial water glass. The recycled water glass could be used as a substitute for the commercial water glass.

Adsorption of oil from waste water by coal:characteristics and mechanism

The work described here was focused on exploring the potential application of coal to purification of oily waste water.Coal was added to oily waste water as an adsorbent and then removed through a flotation process.This allowed economical and highly efficient separation of oil from the waste water.The absorption time,coal type,coal particle size distribution,pH value and oil concentration were investigated.The results indicate that oil absorption by a coal increases for a period of 1.5 h and then gradually tends toward an equilibrium value.It appears that the absorption capacity of anthracite is more than that of lean coal or lignite,given the same coal particle size distribution.The absorption capacity of a coarse coal fraction is less than that of finer coal,given the same of coal type.The absorption capacity of anthracite decreases slightly as the pH increases from 4 to 9.The adsorption of oil on anthracite follows the Freundlich isothermal adsorption law:given initial oil concentrations of 160.5 or 1023.6 mg/L the absorption capacity was 23.8 or 840.0 mg/g.The absorption mechanism consists of two kinds of absorption,a physical process assisted by a chemical one.

Studies on Feasibility of Reverse Osmosis (Membrane) Technology for Treatment of Tannery Wastewater

Tanneries reusing wastewater by combination of conventional and advanced Reverse Osmosis (RO) treatment technologies were assessed for technical and economic viabilities. Conventional treatment methods such as neutralization, clari-flocculation and biological processes are followed to clean the effluents before feeding to RO membrane modules. The characteristics of untreated composite effluents such as pH, biochemical oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids (TSS), total dissolved solids (TDS), and total chromium were in the range of 4.00-4.60, 680-3600 mg/L, 1698-7546 mg/L, 980-1480 mg/L, 4200-14500 mg/L, and 26.4-190 mg/L, respectively. Inorganic ions like Ca2+, Na+, Cl– and SO42– were found more in the wastewaters. Conventional treatments significantly removed the organic pollutants however failed to remove dissolved inorganic salts. Membrane technology removed the salts as well as remaining organic pollutants and the product water is reused in the process. The studied tanneries (5 numbers) have achieved 93-98%, 92-99% and 91-96% removal of TDS, sodium and chloride, respectively. Seventy to eighty five percentage of wastewater was recovered and recycled in the industrial processes. The rejects are subject to either solar evaporation system or Multiple Effect Evaporation (MEE) technology. The resulting salts are collected in polythene bags and disposed into scientifically managed secured land fill (SLF) site. The cost of wastewater treatment for operation and maintenances of RO including the pre-treatments (conventional methods) is INR 100-110 m-3.

THE INVESTIGATION ON PHOTOCATALYTIC TREATMENT OF WASTE WATER CONTAINING PHENOL OVER ZnO

This paper adopts a medium pressure mercury lamp as light source and ZnO powder as catalyst to investigate the effect of radioactive wave length, component of phenol ZnO suspension and stirring method on phenol decomposition rate. The optimized conditions for the phenol decomposition are: (1) Radioactive wave length: 360～420 nm; (2)Phenol concentration in the suspension is less than 200 mg/l; (3)ZnO concentration is 3～8 g/l; (4)pH value is 5～7; (5)Reaction temperature is 25℃～40℃; (6)Agitation at atmosphere. Phenol can decompose in two ways: (1)Reacting with photogenerated cavity; (2)Reacting with ·OH radical.

Structure Characterization and Dephosphorization Effect Analysis of Oyster Shell-silica Micropowder Waste Water Dephosphorization Materials

In this work,the effects of pH value of waste water and initial concentration of phosphorus on dephosphorization materials were investigated.The materials were prepared by shaping,sintering and hydrothermal reshaping oyster shell and silica micro-powder.Different concentrations of phosphorus-contained waste water were simulated with potassium dihydrogen phosphate solution,the effect of dephosphorization was tested with phosphomolybdenum blue spectrophotometer method,and the crystal phase and microstructure of materials were characterized by XRD and SEM methods. It was indicated that dephosphorization was completed in 6 h when the initial phosphorus concentration in waste water was lower than 15 mg/L, and the dephosphorization time prolonged as the increase of phosphorus concentration. It was observed that the pH value of waste water influenced dephosphorization significantly, and neutral subalkalic environment favored dephosphorization. When the pH value was 11, the efficiency of dephosphozation was the greatest. For waste water with an initial concentration of 20 mg/L, the dephosphozation rate is close to 100% in8 h.

Bioaugmentation of two-stage aerobic sequencing batch reactor with mixed strains for high nitrate nitrogen wastewater treatment

Mixed strains Delftia sp.YH01 and Acidovorax sp.YH02,with capability of heterotrophic nitrification-aerobic denitrification,were introduced into a two-stage aerobic sequencing batch reactor to enhance NO3^--N removal.With optimal C/N of 8,efficient NO3^--N removal was achieved at initial NO3^--N concentration of 2000 mg·L−1.Meanwhile,the massive accumulation of NO2^--N was avoided during the long operation.Compared to the one-stage aerobic sequencing batch reactor,the removal efficiency of NO3^--N and TN in the two-stage aerobic sequencing batch reactor was increased by 36.5% and 42.7%,which respectively was 93.8% and 88.4%.Microbial community study showed that the mixed strains have the stronger viability and can synergistically denitrify with the indigenous microorganisms in system,such as Azoarcus,Uncultured Saprospiraceae,Thauera,Paracocccus,which could be major contributors for aerobic denitrification.The proposed technology was shown to achieve high-efficiency treatment of high NO3^--N wastewater through aerobic denitrification.

Anaerobic digestion for waste water poultry manure by UBF reactor

In this experiment the performance of UBF process treatment for wastewater chicken manure was tested under the condition of constant temperature of 35℃ and the volume of UBF is 4 liters. The experiment covered two stages: the first was start up with phase I and phase II, the second was steady state. The following results average of operation period were obtained: (1) During the period of start up phase I operation the biogas production rate 0.39v/(v.day) at the volumetric COD loading rate of 2.97 kg COD/(m 3.d) with COD removal 76.85% and hydraulic retention time of 10.04 hours and phase II the biogas production rate 3.86 v/(v.day) at the volume loading rate 11.69 kg COD/(m 3.d) have been achieved with COD removal 82.47% and HRT 16.45 hours. UBF process had resistance to the quantitative shock load. (2) During the steady state operation, the biogas production rate 9.83v/(v.day) at loading rate of 28.85 kg COD/(m 3.d) and COD removal efficiency 80.03% and hydraulic retention time of 18.73 hours have been achieved for this reactor. The operation of UBF reactor was very stable.

Integrated Low-cost Wastewater Treatment for Reuse in Irrigation

For sustainable wastewater management in developing countries, the implementation of low\|cost, simple treatment systems should be encouraged. In this study, the performance of three treatment schemes was evaluated. The first step in all schemes was upflow anaerobic sludge blanket (UASB). The post treatment was either Algal Pond (AP). Lemna Pond (LP) or Rotating Biological Contactor (RBC). The results show that the performance of the UASB was satisfactory. Mean COD and BOD removal values were 78% and 85% respectively. The combination of UASB with an AP achieved significant improvement in the microbiological quality of the effluent. The geometric mean of fecal coliform in the effluent was 1.3×10 3 MPN/100ml. Residual COD was 143 mg O\-2/L. This relatively high value was due to the presence of algae in the AP effluent. The use of the LP as a post treatment achieved better quality effluent. As indicated by the physico\|chemical characteristics. However, fecal coliform removal was less by one log as compared to the AP effluent. When the RBC was used as a second stage. COD and BOD removal rates were 47% and 66% respectively. Also complete nitrification took place. Fecal coliform density declined by 5 logs.

An Integrated Planning for Rense and Wetland Strategyof Waste Water from Rural Enterprises: A Case Stndy

A waste water reuse engineering was designed and then operated in Hongshan, a small town in ZhejiangProvince, China, in order to solve pollution and shortage of water resources due to the development of ruralenterprises. The results showed that series-structure design and cycling model were two effective modes ofsaving water and decreasing pollutants into environment, and wetland strategy should be a component partof the integrated planning for waste water reuse of rural enterprises. This case study could provide a basisfor the optimum utilization and pollution avoidance of water resources.

Industrial Wastewater Treatment by Using MBR (Membrane Bioreactor) Review Study

This study demonstrated the importance, process, activation and applications of Membrane in bioreactor to treat the waste water. Membrane Bioreactor (MBR) process consists of a biological reactor integrated with membranes that combine clarification and filtration of an activated sludge process into a simplified, single step process. Operating as an MBR allows conventional activated sludge plants to become single step processes, which produce high quality effluent potentially suitable for reuse. Application of MBR technology for industrial wastewater treatment has also gained attention because of the robustness of the process. Theoretically, maintenance of long SRT in MBR is in favor of the retention and development of special microorganisms, which may lead to better removal of refractory organic matter and make the system more robust to load variations and toxic shocks. Literature suggested the conceptual expectation of enhanced biodegradation of hardly biodegradable compounds in MBR does not often come true. Improved biodegradation to certain extent has been reported in a few studies;however the underlying factors leading to such improvement still remains to be elucidated. This is comprehensive review of the studies dealing with recalcitrant industrial wastewater treatment by MBR, and casts light on the strategies to achieve enhanced biodegradation of hardly biodegradable industrial pollutants in MBR.