Coking Wastewater Treatment Plant Research Articles

Biological Treatment of Coke Plant Wastewater with Activated Sludge MBR Technology

Biological Treatment of Coke Plant Wastewater with Activated Sludge MBR Technology

Identification of disinfection by-product precursors from the discharge of a coking wastewater treatment plant

The discharge of a coking wastewater treatment plant is a new point source for DBP precursors.

Bacterial community compositions of coking wastewater treatment plants in steel industry revealed by Illumina high-throughput sequencing

In this study, Illumina high-throughput sequencing was used to reveal the community structures of nine coking wastewater treatment plants (CWWTPs) in China for the first time. The sludge systems exhibited a similar community composition at each taxonomic level. Compared to previous studies, some of the core genera in municipal wastewater treatment plants such as Zoogloea, Prosthecobacter and Gp6 were detected as minor species. Thiobacillus (20.83%), Comamonas (6.58%), Thauera (4.02%), Azoarcus (7.78%) and Rhodoplanes (1.42%) were the dominant genera shared by at least six CWWTPs. The percentages of autotrophic ammonia-oxidizing bacteria and nitrite-oxidizing bacteria were unexpectedly low, which were verified by both real-time PCR and fluorescence in situ hybridization analyses. Hierarchical clustering and canonical correspondence analysis indicated that operation mode, flow rate and temperature might be the key factors in community formation. This study provides new insights into our understanding of microbial community compositions and structures of CWWTPs.

Estrogenic activity and identification of potential xenoestrogens in a coking wastewater treatment plant

In this study, the estrogenic activities in influent and effluents of coking wastewater from different treatment stages were studied using Yeast Estrogen Screen (YES) bioassays. Raw extracts were further fractioned to identify the potential xenoestrogens combined with YES bioassays and gas chromatography–mass spectrometry analysis. Influent, primary effluent, and anaerobic effluent showed high estrogenic activities, with potencies of 1136±269, 1417±320, and 959±69ng/L of 17β-estradiol (E2) equivalent (EEQ), respectively. The potency of estrogenic activity was gradually removed through the treatment processes. In the final effluent, the estrogenic activity was reduced to 0.87ng EEQ/L with a total removal efficiency of more than 99%, suggesting that the estrogenic activity was almost completely removed in the coking wastewater. For the fractions of raw extracts, bioassay results showed that the estrogenic activities were mostly present in the polar fractions. Correlation analysis between estrogenic activities and responses of identified chemicals indicated that potential xenoestrogens were the derivatives of indenol, naphthalenol, indol, acridinone, fluorenone, and carbazole. The estrogenic activity in the final effluent was higher than the predicted no effect concentration (PNEC) for E2, implying that the discharged effluent would probably exert estrogenic activity risk to the aquatic ecosystem in “the worst-case scenario.”

Coke dust enhances coke plant wastewater treatment

Coke plant wastewater contain many toxic pollutants. Despite physico-chemical and biological treatment this specific type of wastewater has a significant impact on environment and human health. This article presents results of research on industrial adsorptive coke plant wastewater treatment. As a sorbent the coke dust, dozen times less expensive than pulverized activated carbon, was used. Treatment was conducted in three scenarios: adsorptive after full treatment with coke dust at 15gL−1, biological treatment enhanced with coke dust at 0.3–0.5gL−1 and addition of coke dust at 0.3gL−1 prior to the biological treatment. The enhanced biological treatment proved the most effective. It allowed additional removal of 147–178mgCODkg−1 of coke dust.

Multispecies acute toxicity evaluation of wastewaters from different treatment stages in a coking wastewater-treatment plant.

Coking wastewater contributes approximately 5% of the total discharge volume of industrial wastewaters every year in China. The toxicity of coking wastewater to aquatic organisms is still unknown. The authors evaluated the toxicity of wastewater from different treatment stages in a coking wastewater treatment plant, South China, using 5 test species belonging to different trophic levels: luminous bacteria, green alga, a crustacean, duckweed, and zebrafish embryos. The raw influent displayed the highest toxicity to the test species, with toxic units ranging from 16.2 to 1176. The toxicity in the wastewater was then gradually removed by sequential primary treatment, biological fluidized-bed treatment, and secondary clarifier treatment. The toxic unit of the final effluent was reduced to 2.26 for the green alga (Pseudokirchneriella subcapitata) and to 0 for the other 4 organisms. Quantitative analysis of metals and polycyclic aromatic hydrocarbons (PAHs) and qualitative scanning by gas chromatography-mass spectrometry showed the presence of a variety of pollutants in the coking wastewaters. Multivariate statistical analysis revealed that the toxicity in the coking wastewater was correlated to the chemical oxygen demand, total nitrogen, ammonia nitrogen, volatile phenols, sulfide, metals (Cr, As, Sb, Hg, Pb, and Ni), and ΣPAHs. Based on the results, it is required to set a safety emission limit value for the discharge of coking wastewater to protect aquatic organisms in the receiving water bodies.

Ion-exchange membrane bioelectrochemical reactor for removal of nitrate in the biological effluent from a coking wastewater treatment plant

Bioelectrochemical reduction of nitrate using an electrode (i.e., cathode) as the electron donor represents a promising method for denitrification; however, this process suffers from the problem of being applied for treating real wastewater, because the cathodic bacteria are susceptible to poisoning by other components in the wastewater. Here we reported the concept of an ion-exchange membrane bioelectrochemical reactor (IEMBER) that integrates the transport of nitrate from a wastewater chamber through an anion-exchange membrane (AEM) with its bioelectrochemical reduction in a separate cathode chamber. Successful removal of nitrate in the biological effluent from a coking wastewater treatment plant was achieved, in good agreement with the obvious cathodic current observed in the IEMBER when its cathode was poised at a potential of −0.50V (vs. SCE). The AEM plays a crucial role in preventing the residuals in the wastewater chamber to enter the cathode chamber, thus avoiding their potential toxicity to the denitrifying bacteria.

Novel insights into anoxic/aerobic1/aerobic2 biological fluidized-bed system for coke wastewater treatment by fluorescence excitation–emission matrix spectra coupled with parallel factor analysis

Fluorescence spectroscopy coupled with parallel factor analysis (PARAFAC) was applied to investigate the contaminant removal efficiency and fluorescent characteristic variations in a full scale coke wastewater (CWW) treatment plant with a novel anoxic/aerobic1/aerobic2 (A/O1/O2) process, which combined with internal-loop fluidized-bed reactor. Routine monitoring results indicated that primary contaminants in CWW, such as phenols and free cyanide, were removed efficiently in A/O1/O2 process (removal efficiency reached 99% and 95%, respectively). Three-dimensional excitation–emission matrix fluorescence spectroscopy and PARAFAC identified three fluorescent components, including two humic-like fluorescence components (C1 and C3) and one protein-like component (C2). Principal component analysis revealed that C1 and C2 correlated with COD (correlation coefficient (r)=0.782, p<0.01 and r=0.921, p<0.01), respectively) and phenols (r=0.796, p<0.01 and r=0.914, p<0.01, respectively), suggesting that C1 and C2 might be associated with the predominating aromatic contaminants in CWW. C3 correlated with mixed liquor suspended solids (r=0.863, p<0.01) in fluidized-bed reactors, suggesting that it might represent the biological dissolved organic matter. In A/O1/O2 process, the fluorescence intensities of C1 and C2 consecutively decreased, indicating the degradation of aromatic contaminants. Correspondingly, the fluorescence intensity of C3 increased in aerobic1 stage, suggesting an increase of biological dissolved organic matter.

Increasing the sensitivity of headspace analysis of low volatility solutes through water removal by hydrate formation

This paper reports on the development of a new headspace analytical technique that is based on water removal by hydrate formation (WRHF). By adding anhydrous salt, the liquid water in an aqueous sample will be removed leaving behind volatile analytes that are fully vaporized at temperatures well below their boiling points. With WRHF, the amount of sample in the headspace can be significantly increased, thereby dramatically improving the detection sensitivity. The technique reduces the risk of possible column damage in gas chromatography (GC) systems. The technique was applied to the determination of phenol at different stages of a coking wastewater treatment plant. The results showed that up to mL-levels of sample solution can be used in WRHF HS-GC analysis when 5g of CaCl2 were used as the anhydrous salt. The detection sensitivity for phenol content was 500 times greater than that in earlier HS-GC work that did not incorporate hydrate formation. The proposed WRHF headspace analysis technique is simple and practical, making it a useful tool for quantifying low concentrations of volatile analytes in aqueous samples.

Advanced oxidation processes with coke plant wastewater treatment.

The aim of this study was to determine the most efficient method of coke wastewater treatment. This research examined two processes - advanced oxidation with Fenton and photo-Fenton reaction. It was observed that the use of ultraviolet radiation with Fenton process had a better result in removal of impurities.

Isolation and Degradation Kinetics of the Quinoline Degradation Bacterium Strains from Coking Wastewater

An aerobic bacterial strain Q1 capable of utilizing quinoline as sole source of carbon, nitrogen and energy was isolated from activated sludge of a coke plant wastewater treatment process. The morphological properties and the phylogenetic analysis based on 16S rDNA sequences showed strain Q1 belonged to thePseudomonassp.. Another strain Q2 was unable to utilize quinoline as sole source of energy alone can coexist with Q1 when quinoline was sole energy. The coexistence of Q1 and Q2 has synergistic effect to quinoline degradation. The biodegradation tests suggested that the kinetics of quinoline biodegradation by Q1 or the combaination of Q1and Q2 strain can be described by Haldane equation kinetically.

Acclimatization of communities of ammonia oxidizing bacteria to seasonal changes in optimal conditions in a coke wastewater treatment plant

The goal of this study was to investigate the correlation between optimal conditions of ammonia oxidation rates (AORs) and communities of ammonia oxidizing bacteria (AOB) adapting to seasonal changes in a full-scale wastewater treatment plant (WWTP). The optimal temperature and pH of specific AORs reflected seasonal variation patterns, showing the lowest values during the cold season, while the highest values in the warm season. Throughout the study period, Nitrosomonas europaea/eutropha and Nitrosomonas nitrosa remained the dominant AOB, indicating resistance to the influences of a changing environment. These results show that the optimal conditions for AOR can be adjusted to accommodate changing environmental conditions, relying on the acclimatization of a stable AOB community to given conditions, without any visible shift in the AOB community.

The occurrence and fate of phenolic compounds in a coking wastewater treatment plant

The occurrence of 14 phenolic compounds (PCs) was assessed in the raw, treated wastewater, dewatered sludge and gas samples from a coking wastewater treatment plant (WWTP) in China. It was found that 3-cresol was the dominant compound in the raw coking wastewater with a concentration of 183 mg L(-1), and that chlorophenols and nitrophenols were in the level of μg L(-1). Phenol was the dominant compound in the gas samples, while 2,4,6-trichlorophenol predominated in the dewatered sludge sample. The anaerobic and aerobic tanks played key roles in the elimination of chlorophenols and phenols, respectively. Analysis of daily mass flows of PCs in WWTP showed that 89-98% of phenols and 83-89% of nitrophenols were biodegraded, and that 44-69% of chlorophenols were adsorbed to sludge, indicating that the fate of PCs was highly influenced by their biodegradability and physical-chemical property.

Thiocyanate Oxidation by Coculture from a Coke Wastewater Treatment Plant

Bacterial strains in an activated sludge aerobic reactor from a coke wastewater were found to be able to utilize thiocyanate as carbon source when the thiocyanate-containing wastewater was deprived of carbon source. This study showed that three thiocyanate-oxidizing bacterial strains, Burkholderia sp., Chryseobacterium sp., and Ralstonia sp. were isolated from the activated sludge of a coke wastewater treatment plant as evidenced by the fact that complete decomposition of thiocyanate was achieved either by coculture or individual pure culture. The thiocyanate biodegradation by the coculture occurred with an optimal pH range between 6.5 and 8.5 and an optimal temperature range between 30°C and 40°C. The biodegradation kinetics of thiocyanate was well fitted with the Andrew-Haldane model, which demonstrated a distinct substrate concentration-inhibited bacterial growth pattern. The effects of different types of additional carbon, nitrogen or sulfur sources on thiocyanate biodegradation were also investigated. Analysis of the end-products indicated that thiocyanate degradation by these strains should proceed via two pathways.

Identification and characterization of polycyclic aromatic hydrocarbons in coking wastewater sludge

GC-MS analysis was performed on the coking sludge from a coking wastewater treatment plant (WWTP) to allow detailed chemical characterization of polycyclic aromatic hydrocarbons (PAHs). The identification and characterization of the isomers of PAHs was based on a positive match of mass spectral data of their isomers with mass spectra databases or based on a comparison of electron impact ionization mass spectra and retention times of target compounds with those reference compounds. In total, 160 PAH compounds including numerous N-, O-, S-, OH-, and Cl-containing derivatives were positively identified for the first time. Quantitative analysis of target compounds was performed in the selected ion-monitoring mode using the internal standard method. The total concentrations of selected compounds in the coking sludge samples from the anaerobic tank, aerobic tank, hydrolytic tank, and secondary clarifier of the WWTP ranged from 1690 ± 585 to 6690 ± 522 mg/kg, which were much higher than those in other industrial and municipal sludges. PAHs with four and five rings were found to be the dominant compounds, and diagnostic ratios of these compounds suggested that they had the characteristics of coal combustion and pyrolysis.

Experimental Research on the Advanced Treatment of Coking Wastewater by Patented Wastewater Treatment Equipment

In this study, we presented an approach to coking wastewater advanced treatment process with a patented wastewater treatment equipment. The samples were collected from the effluents of the biological treatment tank in a coking wastewater treatment plant. With the experiments of four static single factors and the continuing dynamic process, the discussions about the effects of pH value, influent loading, reaction time, and volume ratio on chromaticity, COD and NH3-N respectively were conducted. The experimental results identified that the optimum process parameters were pH of 3, influent load of 1m3/m2•h, reaction time of 4h and volume ratio of 2:1 respectively. When influents of chromaticity, COD and NH3-N were 210 times, 249.4mg/L, and 31.7mg/L respectively , the effluent of chromaticity, COD and NH3-N were 16 times, 49.7mg/L, and 9.5mg/L respectively, these values could meet the National standard of Recycling and Miscellaneous usages of Municipal Sewage on chromaticity, COD and NH3-N requirements.

Pyrene degradation by Pseudomonas sp. and Burkholderia sp. enriched from coking wastewater sludge

A pyrene-degrading consortium was enriched from sludge of coking wastewater treatment plant which included a combination of aerobic and anaerobic reactors. Biodegradation of pyrene by the consortium follows first-order kinetics. Addition of a co-substrate (glucose or anthraquinone) facilitated pyrene degrading. The highest degradation rate was achieved at 35°C and pH 7.0, as glucose was added. In this case, pyrene (100 mg L−1) was degraded by 93.1 % within 36 h. An intermediate, 1-naphthol was detected via GC-MS analysis, indicating that pyrene degradation by the consortium proceeded with a pathway different from that associated with Mycobacterium sp. By comparisons of 16S rRNA gene sequences, two strains in this consortium were identified as Pseudomonas sp. and Burkholderia sp. The enriched pyrene-degrading consortium from coking wastewater treatment system shows highest pyrene-degrading activity compared with the reported pyrene degraders.

Isolation, Screening and Identification of Phenol-Degrading Bacteria from Coking Wastewater

Phenol is the most common pollutant which can be found in several types of industries. It is highly toxic to human beings. To seek the best phenol-degrading bacteria, we collected activated sludge from an aeration tank of the coking wastewater treatment plant, Benxi Iron and Steel Corporation. Five phenol-degrading strains, designated BS3, BS4, BS23, BS28 and BS29, were isolated and screened from activated sludge. Under the conditions of initial phenol 500 mg•L-1,170 rpm and 28°C, the removal efficiencies of BS3, BS4, BS23, BS28 and BS29 strains reached to 79.6%±1.8%, 55.2%±1.0%, 62.4%±2.6%, 78.6%±2.0% and 61.2%±1.9% within 24 h, respectively. By a series of morphological and biochemical and physiological tests, the five phenol-degrading bacteria were identified. The results indicated that they were Pseudomonas spp.. Hence these strains can be effectively used for bioremediation of phenol contaminated water.

Coking wastewater treatment plant as a source of polycyclic aromatic hydrocarbons (PAHs) to the atmosphere and health-risk assessment for workers

PAHs were identified and some of them were determined in the air around a coking wastewater treatment plant (WWTP) using passive air samplers. Seventy seven PAHs were found in the emissions from the degreasing tanks, the aeration tanks and the secondary clarifiers. ∑PAH concentrations within the plant (373.3±27.3–12959.5±685.9ng/m3) were 3–41 times higher compared to the reference sites (315.7±50.2–363.4±77.5ng/m3). The identification of numerous PAHs and high concentrations of these selected ones in the air of the studied sites indicated that the coking WWTP was a new source of atmospheric PAHs. Variations in the PAH pattern were observed in air within the coking WWTP. For example, Flu and Pyr accounted for 35–46% of the total contents at the degreasing tanks, but less than 10% at the hydrolytic tanks. The calculation of the diagnostic ratios suggested that PAHs in the emissions had the source characters of coal combustion. Furthermore, highly elevated PAH concentrations were determined at the degreasing tanks compared to the other tanks (i.e., aeration tanks and secondary clarifiers) and likely associated with their high concentrations in the coking wastewater and increased volatilization at high water temperature. Health risk assessments were carried out by evaluating the inhalation PAH exposure data. The resultant inhalation exposure levels due to TEQBaP for workers ranged from 1.6±0.6 to 71.2±8.2ng/m3, and the estimated lung cancer risks were between 0.1×10−3±0.1×10−4 and 5.2×10−3±0.5×10−3, indicating PAHs in the air around the degreasing tanks and the aerobic tanks would have potential lung cancer risk for the operating workers.

Isolation and characterization of a heterotrophic nitrifier from coke plant wastewater

This study investigated some factors affecting ammonium removal and nitrite accumulation by Alcaligenes faecalis C16, which was isolated from the activated sludge of a coking wastewater treatment plant. Nitrite was produced from ammonium only in the presence of citrate, acetate, meat extract, peptone or ethanol. The highest amount of nitrite was found with citrate as carbon source. A. faecalis C16 could not use glucose, fructose, sucrose and methanol. Under the optimum conditions of initial pH 6.0, C/N 14, 30 °C and 120 rpm, a maximum nitrite accumulation of 28.29 mg/L NO(2)(-)-N was achieved when the organism grew with citrate in four days. Nitrite accumulation increased with the increase of NH(4)(+)-N. Furthermore, A. faecalis C16 was shown to have phenol-degrading capacity during ammonium removal. Metabolism of phenol resulted in acidification of the media, which is not favorable for nitrification, whereas many other carbon sources made the medium more alkaline. However, no inhibitory effect by phenol was observed when phenol and acetate were used as mixed carbon source at different phenol/sodium acetate (P/S) ratios and their pH values were all controlled above 9.2 or P/S ratios below 5:5. These results suggested that A. faecalis C16 has some potential application in industrial wastewater treatment systems.