The degradation kinetic parameters in terephthalic acid (TPA) wastewater for the hybrid strains of Fhh and Fhhh obtained through the protoplast fusion of the fungi Phanerochaete chrysosporium (PC) and Saccharomyces cerevisiae Y99, and the native bacteria YZ1 were measured in this research. The highest level of the specific degradation rate for Fhhh and Fhh during 20h reaction were 0.2238 and 0.2163 h‐1, which were higher than that of their three parental strains and that of the anaerobic bacteria reported. It suggested that the abilities of growth and degradation for Fhh and Fhhh in TPA wastewater were better than their three parental strains. They could create potentials for the purification of TPA wastewater with higher efficiency. 相似文献
The post treatment of simulated tannery wastewater was evaluated in an electrochemical oxidation process under galvanostatic conditions. A continuous flow reactor divided by a cellulosic membrane consisted of Ti/SnO2–Sb anodes and iron cathodes was used. Central composite design and response surface methodology (RSM) were applied to investigate the effects of six operational parameters, namely initial concentration of total phenols (TPh), total chromium (TCr), total ammonia nitrogen (TAN), flow rate (Q), current intensity (I), and electrode surface area (A). Effectiveness of the innovative cellulosic membrane was proven by considerable pH variations in the anolyte and catholyte chambers. A faster removal rate was observed for TPh and TAN, followed by TCr. The treatment level was very sensitive to Q and I in the studied ranges. RSM showed the removal efficiencies of 78.14%, 63.42%, and 86.09% for TPh, TCr, and TAN, respectively, are achieved under optimal conditions with consumption of only 9.03 kWh m?3 electrical energy. Chlorinated compounds such as chloroform, 2,4-dichlorophenol, and chlorobenzene were detected as the degradation intermediates. According to the obtained results, electrolysis in the divided cell with cellulosic membrane is a practical, cost-effective method for advanced treatment of tannery effluents. 相似文献
H.C.M.R. is a fluidised multiphasic reactor. In this reactor the rate of oxygen transfer was studied in order to characterise its efficiency as a system of aerobic treatment. The studied parameters are: The size of the reactor, the volume of the particles, the oxygen transfer rate. Several experiments were carried out with a variation of the above parameters and the results of the experiments are summarised as follows: The overall mass transfer rate coefficient k1a increases with increasing of upflow gas rate (Ug); The overall mass transfer rate coefficient k1a decreases with increasing of the inert support volume (Vs); The overall mass transfer rate coefficient values from cylinder shaped particles were higher than those for disc shaped particles. 相似文献
In the present study, a photoelectrochemical process containing seawater as a natural low-cost supporting electrolyte was used to remove ammonium from wastewater in a continuous flow mode. Based on central composite design (CCD), response surface methodology (RSM) was employed to evaluate the performance of the process in ammonia removal. The effect of four main independent parameters, including initial ammonium concentration, hydraulic retention time (HRT), current intensity and initial pH on the removal of ammonia was evaluated by the model. The optimal initial ammonium concentration, HRT, current intensity and initial pH were 917 mg NH 4? N;·L ?1, 108 min, 1.8 A and 8.4, respectively. The high coefficients (R2=0.97 and adjusted R2=0.94) obtained by the analysis of variance (ANOVA) demonstrated close correlation between predicted and experimental values. Also, treating the reject water from the sludge dewatering unit as an ammonium-rich wastewater showed the effectiveness of the process for treating real wastewaters (86% ammonium removal). The results revealed that the present process can be an efficient method for ammonium removal from polluted effluents in coastal areas based on the availability of seawater as a cost-efficient supporting electrolyte. 相似文献
The effect of physical parameters of cultivation (load volume, temperature, pH, agitation, inoculum size, and incubation period) in the production of laccase by wood-rotting basidiomycete Coriolus hirsutus were studied using diluted molasses distillery wastewater (MDW) as a major composition. Using fractional factorial design, our study first identified load volume, agitation, and inoculum size as statistically significant factors. Optimal preferences and mutual interactions of the factors were then determined by the response surface method, which is based on the center composite design. A quadratic model was used to fit the experimental data. The optimized operational parameters for laccase production were determined to be the following: culture temperature of 25°C, pH 4, load volume of 40 mL diluted MDW in 150 mL flask, agitation rate of 183 r·min?1, inoculation of 11.5% v/v, and cultivation time of 6 d. The experimental validation under these conditions (the maximum laccase production of 2198.2 U·mL?1 was within the confidence interval) subsequently verified the accuracy of the constructed model. Moreover, the removal of chemical oxygen demand and nitrogen of MDW reached 62.85% and 48.00% respectively, and the decolorization ratio under the optimal condition was 41.85%. The enhanced production of laccase by C. hirsutus is a new recovery strategy for MDW. 相似文献
A simple and efficient ionic liquid-based ligandless microextraction method has been developed for preconcentration of cadmium ions (Cd2+) as a step prior to its determination by flame atomic absorption spectrometry (FAAS) with a micro-sample introduction system. In this approach, the ionic liquid (IL) 1-butyl-3-methylimidazolium hexafluorophosphate [C4mim][PF6] and ethanol were used as extractant and dispersive solvents to preconcentrate the Cd2+ in different waters, acid digested scalp hair, and nail samples. Some analytical parameters influencing the extraction efficiency of Cd2+ and its subsequent determination, including pH, IL volume, dispersant solvent volume, sample volume, temperature, incubation time, and matrix effect, were optimized. Under optimal conditions, the limit of detection (LOD), limit of quantification (LOQ), and enhancement factor (EF) were 0.4 μg L?1, 1.3 μg L?1, and 50, respectively. The relative standard deviation (RSD) of 100 μgL?1 Cd2+ was 4.3% (n = 6). The validity of the proposed method was checked by determining Cd2+ in certified reference material (TM-25.3 fortified water) and standard addition; the results showed sufficient recovery (>98%) of Cd2+ within the certified value. The method was applied for preconcentration and determination of cadmium in waters and biological samples. 相似文献
This article aims to determine the significant differences of the seasonal changes of pH, chemical oxygen demand (COD), biological oxygen demand (BOD), and total suspended solids (TSS) parameters in a wastewater stabilization pond. The variation of these parameters followed the seasonal pattern of temperature. The mean seasonal pH of the influent wastewater ranged between 7.8 (in spring) and 7.9 (in summer), while in the final effluents it was between 7.9 (in winter) and 8.3 (in summer). The mean seasonal COD of the influent wastewater ranged between 650?mg?L?1 in spring and 600?mg?L?1 in autumn, whereas in the effluents it was between 150?mg?L?1 in autumn and 270?mg?L?1 in spring. The mean seasonal BOD5 of the influent wastewater ranged between 360?mg?L?1 in autumn and 390?mg?L?1 in winter, whereas in the effluents it was between 66?mg?L?1 in summer and 130?mg?L?1 in winter. The results showed that the percent removals of COD, BOD5 and TSS from final effluents were maximum in summer for COD and BOD5 (76%), summer (83%) and for TSS in winter (78%), respectively. Data analysis showed that there were significant differences between parameters of pH, COD, BOD5 and TSS at four different seasons (p?0.001) in final effluents. 相似文献
The kinetic parameters and the purification rates of the hybrid cell Foaz in soybean processing wastewater (SPW) were measured through a shaking reaction and in two automatic regulated control stable fermentation systems (ARCSFS). The maximum specific growth rate of Foaz was 0.576 h‐1, higher than that of one of its parental strains Rhodobacter sphaeroides P9479 and lower than that of another parental strain Saccharomyces cerevisiae Y9407. The BOD5 removal rate of Foaz in the No. 1 system was 61.3%, higher than those of both its parental strains when the influent BOD5 concentration was 4600 mg/L. The results of this study suggest that the hybrid Foaz has a better capacity of the degradation of organic pollutants in SPW than its parental strains and it may be applicable to the treatment of high concentration organic wastewater. 相似文献
By sending a questionnaire to all companies of the pulp and paper, textile finishing and leather industries in Germany a study ascertained wastewater data concerning the general situation, treatment processes and specific amounts. With these data standard figures used in the EU for the assessment of chemical substances were checked. The volume flows of the industrial sewage treatment were determined for the facilities of all three branches which discharge their wastewater directly to the receiving waters. The 10 percentile score of these facilities amounted to only a quarter of the EU standard figure of 2,000 m3/d. This value is related to a standardised waste water treatment plant within the EU, which treated the wastewater of 200 l/d from 10,000 inhabitants. The analyses of the entire branch in each case yield dilution factors of 20–70% of the EU standard value of 10. Only the full tanning leather companies yielded a dilution factor of 10. The volume flows of the sewage treatment plants of the facilities discharging to the sewer system exceeds 2,000 m3/d in call cases. 相似文献
Trimethylolpropane (TMP) wastewater is one of the most toxic petrochemical wastewater. Toxicants with high concentrations in TMP wastewater often inhibit the activity of microorganisms associated with biological treatment processes. The hydrolysis acidification process (HAP) is widely used to pretreat petrochemical wastewater. However, the effects of HAP on the reduction of wastewater toxicity and the relevant underlying mechanisms have rarely been reported. In this study, an HAP reactor was operated for 240 days, fed with actual TMP wastewater diluted by tap water in varying ratios. The toxicity of TMP wastewater was assessed with the inhibition ratio of oxygen uptake rate. When the organic loading rates were lower than 7.5 kg COD/m3/d, the toxicity of TMP wastewater was completely eliminated. When the actual TMP wastewater was directly fed into the reactor, the toxicity of TMP wastewater decreased from 100% to 34.9%. According to the results of gas chromatographymass spectrometry analysis, four main toxicants contained in TMP wastewater, namely, formaldehyde, 2-ethylacrolein, TMP and 2-ethylhexanol, were all significantly removed, with removal efficiencies of 93.42%, 95.42%, 72.85% and 98.94%, respectively. Compared with the removal efficiency of CODCr, the reduction rate of toxicity is markedly higher by HAP. In addition, the change of microbial community in the HAP reactor, along the operation period, was studied. The results revealed that, compared with the seed sludge, Firmicutes became the dominant phylum (abundance increased from 0.51% to 57.08%), followed by Proteobacteria and Bacteroidetes (abundance increased from 59.75% to 25.99% and from 4.70% to 8.39%, respectively).
The paper examines how a public wastewater treatment plant balances objectives of cost minimization and pollution prevention. The parameters of the objective function and state equation in an optimal control model are estimated using maximum entropy and time series observations of water quality and expenditures for wastewater treatment. The estimation method does not require restrictions needed by other techniques used to estimate nonlinear, ill-posed problems. The parameter estimates indicate that the treatment plant emphasizes water quality enhancement over cost minimization. Results from the sensitivity analysis show that the plant favors conventional treatment over pollution prevention. 相似文献
In this study, three sequential batch biofilm reactors (SBBRs) were operated for 155 days to evaluate the performance of completely autotrophic nitrogen removal over nitrite (CANON) process under different aeration modes and dissolved oxygen (DO). Synthetic wastewater with 160-mg NH4+-N/L was fed into the reactors. In the continuously-aerated reactor, the efficiency of the ammonium nitrogen conversion and total nitrogen (TN) removal reached 80% and 70%, respectively, with DO between 0.8–1.0 mg/L. Whereas in the intermittently-aerated reactor, at the aeration/non-aeration ratio of 1.0, ammonium was always under the detection limit and 86% of TN was removed with DO between 2.0–2.5 mg/L during the aeration time. Results show that CANON could be achieved in both continuous and intermittent aeration pattern. However, to achieve the same nitrogen removal efficiency, the DO needed in the intermittently-aerated sequential batch biofilm reactor (SBBR) during the aeration period was higher than that in the continuously-aerated SBBR. In addition, the DO in the CANON system should be adjusted to the aeration mode, and low DO was not a prerequisite to CANON process. 相似文献
Roxarsone (3-nitro-4-hydroxyphenylarsonic acid, ROX) has been widely used for decades as an organoarsenic feed additive to control intestinal parasites and improve feed efficiency in animal production. However, most of the ROX is excreted into the manure, causing arsenic contamination in wastewater. The arsenic compounds are toxic to microorganisms, but the influence of continuous ROX loading on upflow anaerobic sludge blanket (UASB) reactor is still unknown. In this study, the impact of ROX and its degradation products on the performance of the UASB reactor and the degradation and speciation of ROX in the reactor were investigated. The UASB reactor (hydraulic retention time: 1.75 d) was operated using synthetic wastewater supplemented with ROX for a period of 260 days. With continuous ROX addition at 25.0 mg·L–1, severe inhibition to methanogenic activity occurred after 87 days operation accompanied with an accumulation of volatile fatty acids (VFAs) and a decline in pH. The decrease of added ROX concentration to 13.2 mg·L–1 did not mediate the inhibition. As(III), As (V), MMA(V), DMA(V), HAPA and an unknown arsenic compound were detected in the reactor, and a possible biotransformation pathway of ROX was proposed. Mass balance analysis of arsenic indicated that 60%–70% of the arsenic was discharged into the effluent, and 30%–40% was precipitated in the reactor. The results from this study suggest that we need to pay attention to the stability in the UASB reactors treating organoarsenic-contaminated manure and wastewater, and the effluent and sludge from the reactor to avoid diffusion of arsenic contamination.
The use of Rooibos shoots, a natural adsorbent, for cadmium removal from wastewater is proposed. The effects of initial pH, adsorbent dosage, contact time, and initial concentration were investigated in the batch adsorption mode. The optimum pH was found to be 5.5. Isotherm and kinetic data were modeled; the data fitted best to the Freundlich model, and, kinetically, the adsorption was of pseudo-second order as shown by the high R2 value of 0.9928 along with close agreement between the experimental qe (13.9 mg g?1) and calculated qe (14.24 mg g?1) values. The studied biomass material was found to be effectively used for removal of cadmium from contaminated mine wastewater. 相似文献
In order to improve the nitrogen removal efficiency and save operational cost, the feasibility of the alternating aerobic-anoxic process (AAA process) applied in a sequencing batch reactor (SBR) system for nitrogen removal was investigated. Under sufficient influent alkalinity, the AAA process did not have an advantage over one aerobicanoxic (OAA) cycle on treatment efficiency because microorganisms had an adaptive stage at the alternating aerobic-anoxic transition, which would prolong the total cycling time. On the contrary, the AAA process made the system control more complicated. Under deficient influent alkalinity, when compared to OAA, the AAA process improved treatment efficiency and effluent quality with NH4+-N in the effluent below the detection limit. In the nitrification, the average stoichiometric ratio between alkalinity consumption and ammonia oxidation is calculated to be 7.07 mg CaCO3/mg NH4+-N. In the denitrification, the average stoichiometric ratio between alkalinity production and NO3?-N reduction is about 3.57 mg CaCO3/mg NO3?-N. As a result, half of the alkalinity previously consumed during the aerobic nitrification was recovered during the subsequent anoxic denitrification period. That was why the higher treatment efficiency in the AAA process was achieved without the supplement of bicarbonate alkalinity. If the lack of alkalinity in the influent was less than 1/3 of that needed, there is no need for external alkalinity addition and treatment efficiency was the same as that under sufficient influent alkalinity. Even if the lack of alkalinity in the influent was more than 1/3 of that needed, the AAA process was an optimal strategy because it reduced the external alkalinity addition and saved on operational cost. 相似文献
The occurrence of antibiotic-resistant bacteria and antibiotic resistance genes (ARGs) has been intensively investigated for wastewater treatment systems treating single class of antibiotic in recent years. However, the impacts of alternately occurring antibiotics in antibiotic production wastewater on the behavior of ARGs in biological treatment systems were not well understood yet. Herein, techniques including high-capacity quantitative PCR and quantitative PCR (qPCR) were used to investigate the behavior of ARGs in an anaerobic–aerobic full-scale system. The system alternately treated three kinds of antibiotic production wastewater including ribostamycin, spiramycin and paromomycin, which referred to stages 1, 2 and 3. The aminoglycoside ARGs (52.1–79.3%) determined using high-capacity quantitative PCR were the most abundant species in all sludge samples of the three stages. The total relative abundances of macrolide–lincosamide–streptogramin (MLS) resistance genes and aminoglycoside resistance genes measured using qPCR were significantly higher (P < 0.05) in aerobic sludge than in sewage sludge. However, the comparison of ARGs acquired from three alternate stages revealed that MLS genes and the aminoglycoside ARGs did not vary significantly (P > 0.05) in both aerobic and anaerobic sludge samples. In aerobic sludge, one acetyltransferase gene (aacA4) and the other three nucleotidyltransferase genes (aadB, aadA and aadE) exhibited positive correlations with intI1 (r2 = 0.83–0.94; P < 0.05), implying the significance of horizontal transfer in their proliferation. These results and facts will be helpful to understand the abundance and distribution of ARGs from antibiotic production wastewater treatment systems.