Biodegradability of terephthalic acid in terylene artificial silk printing and dyeing wastewater

As the characteristic pollutant, terephthalic acid(TA)was in charge of 40%—78% of the total COD of terylene artificial silk printing and dyeing wastewater(TPW-water). The studies on biodegradability of TA were conducted in a serial of activated sludge reactors with TPW-water. TA appeared to be readily biodegradable with removal efficiency over 96.5% under aerobic conditions, hardly biodegradable with removal efficiency below 10% under anoxic conditions and slowly biodegradable with a turnover between 31.4% and 56.0% under anaerobic conditions. TA also accounted for the majority of BOD in TPW-water. The process combined by anoxic, anaerobic and aerobic activated sludge reactor was suitable for TA degradation and TPW-water treatment. Further, the aerobic process was essentially much more effective than the anaerobic or anoxic one to degrade TA in TPW-water.

Microwave enhanced chemical reduction process for nitrite-containing wastewater treatment using sulfaminic acid

High-concentration nitrite-containing wastewater that presents extreme toxicity to human health and organisms is difficult to be treated using traditional biological process. In this study, a novel microwave-enhanced chemical reduction process （MECRP） using sulfarninic acid （SA） was proposed as a new manner to treat such type of wastewater. Based on lab-scale experiments, it was shown that 75%-80% nitrite （NO2-） could be removed within time as short as 4 min under 50 W microwave irradiation in pH range 5-10 when molar ratio of SA to nitrite （SA/NO2-） was 0.8. Pilot-scale investigations demonstrated that MECRP was able to achieve nitrite and chemical oxygen demand （COD） removal with efficiency up to 80% and 20%, respectively under operating conditions of SA concentration 80 kg/m3, SA/NO2- ratio 0.8, microwave power 3.4 kW, and stirring time 3 min. Five-day biological oxygen demand （BODs）/COD value of treated effluent after MECRP was increased from 0.05 to 0.36 （by 620%）, which clearly suggested a considerable improvement of biodegradability for subsequent biological treatment. This study provided a demonstration of using microwave irradiation to enhance reaction between SA and nitrite in a short time, in which nitrite in wastewater was completely converted into nitrogen gas without leaving any sludge and secondary pollutants.

Purified terephthalic acid wastewater biodegradation and toxicity

The biodegradation and toxicity of the purified terephthalic acid（PTA） processing wastewater was researched at NJYZ pilot with the fusant strain Fhhh in the carrier activated sludge process（ CASP）. Sludge loading rate（SLR） for Fhhh to COD of the wastewater was 1.09 d^-1 and to PTA in the wastewater was 0.29 d^-1. The results of bioassay at the pilot and calculation with software Ebis3 showed that the 48h-LC50 （median lethal concentration） to Daphnia magna for the PTA concentration in the wastewater was only 1/10 of that for the chemical PTA. There were .5 kinds of benzoate pollutants and their toxicities existing in the wastewater at least. The toxicity parameter value of the pure chemical PTA cannot be used to predicate the PTA wastewater toxicity. The toxicity of the NJYZ PTA wastewater will be discussed in detail in this paper.

A two-stage anaerobic system for biodegrading wastewater containing terephthalic acid and high strength easily degradable pollutants

The high strength easily biodegradable pollutants (represented by COD E) are strong inhibitors of terephthalic acid (TA) anaerobic biodegradation. At the same time, TA can inhibit easily biodegradable pollutants removal under anaerobic conditions to a limited extent. This mutual inhibition could happen and cause a low removal efficiency of both TA and COD E, when the effluent from TA workshops containing TA and easily biodegradable pollutants are treated by a single anaerobic reactor system. Based upon the treatment kinetics analysis of both TA degradation and COD E removal, a two stage up flow anaerobic sludge blanket and up flow fixed film reactor(UASB UAFF) system for dealing with this kind of wastewater was developed and run successfully at laboratory scale. An UASB reactor with the methanogenic consortium as the first stage removes the easily biodegradable pollutants(COD E). An UAFF reactor as the second stage is mainly in charge of TA degradation. At a COD E loading of 15.3 g/(L\5d) and a TA loading of 1.4 g/(L\5d), HRT 18.5h, the COD E and TA removal rate of the system reached 89.2% and 71.6%, respectively.

Membrane bioreactor process of organic wastewater from brassylic acid manufacturing plant

The wastewater treatment from brassylic acid manufacturing plant using membrane bioreactor (MBR) was studied. The membrane bioreactor consisted of batch-operation biological aeration tank and ultrafiltration evaluation tank. The content of test included the affection of variation operation conditions on ultrafiltration separation, the general characteristics of MBR process, and the difference comparing with the conventional biological treatment. The results are as follows: (1) among the test membrane material, polyether sulphone (PES) membrane is more suitable for the wastewater treatment; (2) when the cutoff molecular weight is among 10000-50000, the higher the cutoff molecular weight, the bigger the water flux is in the test; (3) under the operation pressure, water flux increases accompanying with the increasing of operation pressure; (4) the paper filtered COD concentration has more affection on the water flux than the suspended solid concentration; ( 5) as they volume loading of MBR increases, the accumulation of high molecule organic substance and colloid increases, the membrane,permeate COD concentration and paper filtered COD concentration increase too, meanwhile the water flux reduces; (6) when the sludge retention time of activated sludge of MBR increases, the accumulation of high molecule organic substance and colloid reduces, the membrane permeate (:OD concentration and paper filtered COD concentration reduce too, and the water flux increases; (7) comparing with the conventional biological process, the microbial activity is higher, but the microbial species is less.

Reactive Crystallization of Calcium Sulfate Dihydrate from Acidic Wastewater and Lime

The present work focused on the recycle of the sulfate and the metal ions from acidic wastewater discharged by nonferrous metallurgical industry. The effects of the temperature, the reactant concentration, the stirring speed and the metal ions on the reactive crystallization process of calcium sulfate between sulfuric acid and lime were systematically investigated. The morphology of the precipitated crystals evolved from platelet-like and needle-like shape to rod-like shape when the temperature was increased from 25 to 70 °C. An increase in the agglomeration of calcium sulfate was found with increasing lime concentration. Metal ions markedly retard the rate of crystallization of calcium sulfate dihydrate. The crystallization of gypsum was slowed with the existence of Mg2+in the solution, and the morphology of gypsum was transformed from platelet-like shape to rod-like shape when Mg2+ concentration reached 0.08 mol·L 1. The amorphous ferric hydroxide was coated on the calcium sulfate after the co-precipitation process while Zn2+and Al3+ions in the solution enhanced the agglomeration of the calcium sulfate by absorbing on the surface of the crystals. Comprehensive acidic wastewater containing heavy metals was efficiently purified by the two stage lime neutralization technology, and highly agglomerated gypsum precipitates with needle-like shape were obtained. The precipitates could be purified by sulfuric acid washing, and the metal ions were effectively separated from the calcium sulfate by-products.

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 extraction 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 distribution coefficient of 40 is obtained.Phenol saturation concentration in castor oil acid is 1.03 mol·L 1after extraction for 4 times.The equilibrium constant(Kex) at 25 °C is 8.41 and the endothermic enthalpy(ΔH) is 1.513 kJ·mol 1.The Gibbs free energy(ΔG) is 5.277 kJ·mol 1and the value of ΔS is calculated to be 22.3 J·mol 1·K 1.

Reductive recovery of manganese from low-grade manganese dioxide ore using toxic nitrocellulose acid wastewater as reductant

The hydrometallurgical strategy of extracting Mn from low-grade Mn ores has attracted attention for the production of electrolytic manganese metal(EMM). In this work, the reductive dissolution of low-grade Mn O2 ores using toxic nitrocellulose acidic wastewater(NAW) as a reductant was investigated for the first time. Under the optimized conditions of an Mn O2 ore dosage of 100 g·L-1, an ore particle size of-200 mesh, concentrated H2 SO4-to-NAW volume ratio of 0.12, reaction temperature of 90°C, stirring speed at 160 r·min-1, and a contact time of 120 min, the reductive leaching efficiency of Mn and the total organic carbon(TOC) removal efficiency of NAW reached 97.4% and 98.5%, respectively. The residual TOC of 31.6 mg·L-1 did not adversely affect the preparation of EMM. The current process offers a feasible route for the concurrent realization of the reductive leaching of Mn and the treatment of toxic wastewater via a simple one-step process.

Construction of hybrid cell with Phanerochaete chrysosporium to degrade terephthalic acid wastewater——(I) phenotype evidence

The fungi Phanerochaete chrysosporium (PC) and Saccharomyces cerevisiae Y99 and the native bacterium YZ1 were the three parental strains for construction of hybrid cells through protoplast fusion to degrade terephthalic acid (TPA) wastewater. The results showed that the native bacterium YZ1 protoplasm could integrate with that of PC to form the hybrid cell Fhh and the fungus Y99 protoplasm also could integrate with that of Fhh to form the hybrid cell Fhhh. The protoplasts of YZ1 and Y99 could change the morphology of PC spore and mycelium for two times. The hybrid cell Fhhh got the best growth and degradation abilities in the wastewater. It suggested that the hybrid strains obtained from the inter\|kingdom protoplast fusion of the three parental strains could create potential for the purification of TPA wastewater.

The Extraction of Lactic Acid from Fermentative Marigold Wastewater

As a natural yellow pigment,lutein is widely used in the human food and forage.A lot of wastewater is generated in this industry.It is urgent to deal with fermentative marigold wstewater for lutein industry.How to process the wastewatwer is more important.Centre on the process of fermentative marigold wstewater,used by polyaluminium chloride to flocculate,active carbon to bleach,then evaporating in the vacuum state and getting lactic acid finally.

THEATMENT OF WASTEWATER FROM PRODUCTION PROCESS OF 2,3-ACID

Wastewater from production process of 2,3-acid was treated by adsorption usingmacroporous resin NDA-708. After only one-step treatment by resin adsorption, removalefficiency of three kinds of naphthalene chemicals was above 99%, removal efficiency ofCODcr was above 96% Under proper operating condition, desorption efficiency wasaround 100%. The running records of the industrial facility showed that the naphthlenechemicals in desorption effluent could be reused without obvious influence on the qualityOf the product.

TREATMENT AND RESOURSE REUSE OF INDUSTRIAL WASTEWATER FROM PRODUCTION PROCESS OF PHENYL ACETIC ACID

The effluent from phenyl acetic acid (PhCH2COOH) production process can betreated with NDA-999 macroporous polymeric adsorbent with about 100% removalefficiency of PhCH2COOK benzyl alcohol (PhCH2OH)and benzaldehyde (PhCHO) aswell as the decrease in Total Organic Carbon (TOC)from 4691mg/l to <300mg/L. 3. 7kgPhCH2COOH and 120kg NaCl will be recovered from per m3 wastewater and theadsorbent can be reused after being regenerated by NaOH aqueous solution andmethanol. Good economic, social and environmental results can be achieved with thismethod.

Comparative study of thermophilic and mesophilic anaerobic treatment of purified terephthalic acid (PTA) wastewater

The paper provides a critical comparison between mesophilic and thermophilic anaerobic treatment of PTA wastewater through diagnosis of a case study. Aspects covered are bioavailability, biodegradability, microbial population, thermodynamics, kinetics involved and bio-reactor design for PTA wastewater treatment. The results of the case study suggests that one- stage thermophilic anaerobic reactor coupled with coagulation-flocculation pre-treatment unit and an aerobic post treatment unit could be techno-economically viable for PTA wastewater treatment to ensure that the final effluent quality conforms to the international standard. The in-formation emanated from this study could be useful and thought provoking to the professionals and academia in the area of PTA wastewater treatment and can serve as impetus toward the development of research lines in similar problems like the treatment of other petrochemical wastewater such as phenol-con- taining wastewater, benzene/benzoic acid-con- taining wastewater or wastewater from other similar industrial settings.

Process Optimization on Anaerobic Treatment of Citric Acid Wastewater

[Objective] The aim was to obtain higher COD removal rate so as to guide the process of citric acid industrial wastewater. [Method] The effects of controllable factors, acidification time, hydraulic retention time, and influent COD concentration, in-anaerobic treatment process of citric acid wastewater on COD removal rate were studied and the COD removal rate was optimized by response surface method. [Result] There was no interaction between acidification time and the other two factors. It was showed that hydraulic retention time and influent COD concentration had significant effect on COD removal rate and there was interaction between the two factors. The optimum COD removing process conditions was as follows: acidification time 1.53 h, hydraulic retention time 3.52 h and influent COD concentration 2 698 mg/L. Under the optimized conditions, the COD removal rate was 93.31% and it was much closed to the experimental result, 93.29%. [Conclusion] Using response surface method to optimize the anaerobic treatment of citric acid wastewater can result in optimized achievement.

ADSORPTION AND DESORPTION OF DSD ACID MANUFACTURING WASTEWATER ON MACROPOROUS RESIN

4,4’-diaminostilbene-2, 2’-disulfonic acid (DSD acid) manufacturing wastewater was treated by a macroporous resin in a fixed-bed column. The results showed that this method was suitable for removal of chemical oxygen demands (COD) and color. About 91% COD and 99.5% color removal were obtained under the optimum adsorption conditions, i.e. temperature 20℃, flow rate 1bed volume/hour (BV/hr) and pH1-2. The resin was efficiently regenerated with aqueous sodium hydroxide and water. Furthermore, 65.5% of 4,4’-dinitrostilbene-2, 2’-disulfonic acid (DNS) could be recovered from wastewater for possible recycling to the manufacturing process. The adsorption capacity of resin remained constant during the repetition process of adsorption and desorption.

New perspectives in free nitrous acid (FNA) uses for sustainable wastewater management

The biocidal effects of free nitrous acid (FNA) have found applications in multiple units in an urban wastewater system, including sewer networks, wastewater treatment processes, and sludge treatment processes. However, these applications are associated with chemical costs as both nitrite and acid are needed to produce FNA at the required levels. The recent discovery of novel acid-tolerant ammonia oxidizers offers the possibility to produce FNA from domestic wastewater, enabling the development of next-generation FNA-based technologies capable of achieving self-sustaining FNA production. In this study, we focus on the concept of in situ FNA generation facilitated by acid-tolerant ammonia oxidizers and highlight the multiple benefits it creates, after a brief review of the historical development of FNA-based technologies. We will discuss how wastewater systems can be made more energy-efficient and sustainable by leveraging the potential of acid-tolerant ammonia oxidizers.

Biofilm structure and its influence on clogging in drip irrigation emitters distributing reclaimed wastewater

Using reclaimed wastewater for crop irrigation is a practical alternative to discharge wastewater treatment plant effluents into surface waters.However,biofouling has been identified as a major contributor to emitter clogging in drip irrigation systems distributing reclaimed wastewater.Little is known about the biofilm structure and its influence on clogging in the drip emitter flow path.This study was first to investigate the microbial characteristics of mature biofilms present in the emitters and the effect of flow path structures on the biofilm microbial communities.The analysis of biofilm matrix structure using a scanning electron microscopy（SEM） revealed that particles in the matrix of the biofilm coupled extracellular polysaccharides（EPS） and formed sediment in the emitter flow path.Analysis of biofilm mass including protein,polysaccharide,and phospholipid fatty acids（PLFAs） showed that emitter flow path style influenced biofilm community structure and diversity.The correlations of biofilm biomass and discharge reduction after 360 h irrigation were computed and suggest that PFLAs provide the best correlation coeffcient.Comparatively,the emitter with the unsymmetrical dentate structure and shorter flow path（Emitter C） had the best anti-clogging capability.By optimizing the dentate structure,the internal flow pattern within the flow path could be enhanced as an important method to control the biofilm within emitter flow path.This study established electron microscope techniques and biochemical microbial analysis methods that may provide a framework for future emitter biofilm studies.

Predication of Fhhh potential in PTA wastewater treatment

Ebis is the intelligent environmental biotechnological informatics software developed for judging the effectiveness of the microorganism strain in the industrial wastewater treatment system(IWTS) at the optimal status. The parameter, as the objective function for the judgment, is the minimum reactor volume( V _ min ) calculated by Ebis for microorganism required in wastewater treatment. The rationality and the universality of Ebis were demonstrated in the domestic sewage treatment system(DSTS) with the data published in USA and China at first,then Fhhh strain's potential for treating the purified terephthalic acid(PTA) was proved. It suggests that Ebis would be useful and universal for predicating the technique effectiveness in both DSTS and IWTS.

Diatomaceous silica filter aid filtration for the effective separation of colloidal Cr（OH）＿3 precipitate from tanning wastewater

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Potential of <i>Dictyosphaerium</i>sp. LC172264 Concomitant Remediation of Cassava Wastewater and Accumulation of Lipids for Biodiesel Production

As a way of making algal feedstock feasible for biofuel production, simultaneous utilization of microalga Dictyosphaerium sp. LC172264 for cassava wastewater remediation and accumulation of lipids for biodiesel production was investigated. The algal biomass, lipid contents and composition were measured from the autotrophic, heterotrophic and mixotrophic cultured algal cells. Physicochemical parameters of the cassava wastewater and bioremediation potentials were measured. Biodiesel properties were deduced and compared with the standards. The results showed that mixotrophic culture was the best for both biomass accumulation (1.022 g/L) and lipid contents (24.53%). Irrespective of the culture condition, the predominant fatty acids were similar and included 11-Octadecenoic acid (vaccenic acid (C19H36O2), oleic acid (C18H34O2) and 14-methyl pentadecanoic acid (isopalmitic acid (C17H34O2). The percentage reduction of total dissolved solids was 79.32% and 89.78% for heterotrophy and mixotrophy respectively. Biochemical oxygen demand was 72.95% and 89.35%, chemical oxygen demand was 72.19% and 84.03% whereas cyanide contents reduced from the initial value of 450 mg/L to 93.105 (79.31%) and 85.365 mg/L (81.03%) respectively. Dictyosphaerium sp. showed good growth and lipid production under mixotrophic condition and produced good quality biodiesel under the three cultivation modes. Even though both mixotrophic and heterotrophic conditions had good promise of cassava wastewater remediation by Dictyosphaerium sp., mixotrophy showed superiority.