Advanced Materials Research Vol. 777

Abstract: To investigate nutrient removal and biological community structure in wastewater treatment system under different ratio of C/N/P, hybrid biofilm reactor (HBR) and sequencing batch reactor (SBR) in lab scale were set up. Results showed that both HBR and SBR achieved the best removal efficiency of nitrogen and phosphorus when C/N/P=100/6.25/1. With the rise of C/N/P from 50/6.25/1 to 100/6.25/1, the removal efficiencies of NH₃-N were greater than 93% in three phases of both reactors; the efficiencies of TN were increased from 65% to 79% in SBR while these values at HBR were from 73% to 86%; the efficiencies of TP were increased from 42% to 93% in SBR while these values at HBR were from 32% to 93%. Microbial community structure response to different C/N/P was determined by PCR-DGGE technology. Similarity coefficient was lowest and denitrifying phosphate accumulating bacteria became dominant bacteria in SBR when C/N/P was 100/6.25/1. There were many functional bacteria in HBR, such as bacteria for removing nutrients (Uncultured BacteroidetesFJ828150), bacteria for removing organic (Uncultured Saprospiraceae) bacteria for removing nitrogen (Ferribacterium sp.), and nitrifying bacteria (Uncultured Nitrospira sp.) which became dominant bacteria. Because of microbial diversity index of biofilm was up to 3.3, similarity coefficient was as low as 43.4%.

Abstract: Experiment studies the startup of Anammox and the effect of pH and temperature on the denitrification performance of Anammox. We take the UASB reactor for Anammox startup experimental study, and study the removal of NH₄⁺-N and NO₂^--N under different temperature and pH. Controlling the influent NH₄⁺-N/NO₂^--N concentration ratio is 1:1.32, the initial concentration of NH₄⁺-N is 50 mg/L, then increase NH₄⁺-N concentration with gradient of 50 mg/L.We detect the influent and effluent NH₄⁺-N and NO₂^--N and effluent NO₃^--N concentration .We also Control the temperature (20°C~40°C) and the pH (6.0~9.0) to study the influencing factors. The optimum temperature is 30°C, the removal rate can reach more than 80%, and the optimum pH is 8, the NH₄⁺-N and NO₂^--N highest removal rate is 82.92% and 87.59%. The effect of the Anammox reaction can be efficient promotion of denitrification and provides theory basis, which provides reference for engineering application on actual conditions.

Abstract: The volatile fatty acids (VFAs) are kinds of effective external carbon source for enhanced biological nutrients removal. Volatile fatty acids (VFAs) production from anaerobic fermentation from cassava stillage (CS) wastewater, starch wastewater (SW) and the yellow wine wastewater (YWW) was conducted in batch tests. The VFAs production potential and the characteristics of the fermentative liquid were compared and discussed. Experimental results indicated that the cassava stillage wastewater and the starch wastewater were preferable feed for anaerobic VFAs fermentation. Acetic acid, propionic acid and butyric acid were the main components of the VFAs with respective percentage of 36.5%, 20% and 40% at the end of its fermentation.

Abstract: This study aimed to evaluate the effect of carbon nitrogen ratio (COD/N) on simultaneous nitrification and denitrification (SND) via nitrite technology in SBBR and the process control. Under the condition of different C/N ratios respectively 1.8, 3.6, 7,5,11.1 and 13.7, the various indices of the removal efficiency in the system and DO, ORP, and pH in the process of reaction were investigated. The C/N ratio was found to be an important limiting factor for SBBR simultaneous nitrification and denitrification via nitrite process. After integrating the factor of energy consumption and removal efficiency, we obtained that the optimum C/N ratios control range from 7.5 to 11.1, reaction time was between 225 min and 315 min, nitrite accumulation rate was between 72.83 % and 78.7 %, COD removal rate was between 92.31 % and 93.08 %, the total nitrogen removal rate was between 81.0 % and 85.86 %. For steady-state simultaneous nitrification and denitrification via nitrite process in SBBR, the jump point (C) on the DO, pH and ORP curve at reaction later period can be used as a control point to indicate the end of the reaction.

Abstract: The integrated process of spray aeration, falling water aeration and bio-filter bed was used for treating groundwater with high iron, manganese and ammonia nitrogen (NH₄⁺-N). The removal efficiencies of iron, manganese and NH₄⁺-N reached 99.1%, 95.0% and 85.2%, and corresponding effluent iron and manganese decreased to 0.1 and 0.05 mg/L. Microbial analysis results indicated that the β-Proteobacteria was predominant microorganisms, in which Gallionella and Leptothrix were main iron-removal bacteria and manganese-removal bacteria, respectively. Simultaneously, Pseudomona, belonged to γ-Proteobacteria, could absorb and oxidize free manganese to be manganese dioxide (MnO₂) by extracellular oxidase.

Abstract: An acidophilic strain was isolated from drainage in Shanxi coal mine, after 16SrDNA amplification and sequencing analysis, it was identified to be Acidithiobacillus ferrooxidans. The ferrous ion oxidation rate of At.f and pH value were studied during its growth, the results showed that, the strain entering into the exponential growth phase needed about 30 hours, and the oxidation rate was more than 99% after 60 hours. The pH value increased from 2.08 to 2.64 at first 30 hours and then decreased to 2.0, and finally maintained at 2.0 in the whole growth process. The isolated strain provided a potential alternative method to handle the steel-picking sulfuric acid waste liquor.

Abstract: The combined process of coagulation, hydrolytic acidification and contact oxidation was applied to treat the jeans washing wastewater, and the microorganism and COD concentration in the contact oxidation pond was monitored 40 consecutive days. the results showed that Vorticella, rotifers, arcellas, chironomid larvae, nematodes of the genus, changed in the number of the wastewater treatment had obvious indicating effect, activated sludge on the chromaticity of grain had obvious effect of adsorption, and flocculation particle morphological changes could also play a role in indicating.

Abstract: Electrokinetic remediation is an effective technology to enhance bioremediation of oil-contaminated soil as the transport process of non-polar organic contaminants in soil was promoted under low-power direct current electric fields. In this study three treatments including the application of electric field treatment alone, inoculation treatment alone, and combination of the application of electric field and inoculation treatment were carried out. The results indicated that highest removal efficiency was 83% in couple of the application of electric field and inoculation treatment. TPH concentration decreased from 6000 mg.kg^-1 to 2000 mg.kg^-1 when a 30 voltage direct current electric field was applied to oil-contaminated soil for 10 min after 4 days. It was observed that dehydrogenase activity had no increase after application direct current electric field. However, the TPH degradation efficiency was 52% higher than the control treatment. GC analysis showed that n-alkanes (C₁₄-C₃₁) were preferentially degraded, and soil remaindered more low quality compounds after the application of electric field treatment applied 52 days. These results indicated that the application of electric field improved degradation of inoculated bacteria through promoting the transport of nutrients, such as nitrogen and phosphorous and electron acceptors.

Abstract: In most field studies, enhancing biodegradation of petroleum hydrocarbons depends on the specific microbial population present. It is a dispute whether inoculation microbial consortium improved the degradation of petroleum because indigenous microorganism can easily adapt to surroundings and contend for inoculation microbial consortium. Therefore, all of three technologies (natural attenuation, biostimulation and bioaugmentation) were evaluated. After 8 weeks of bioremediation, it was observed that bioaugmentation most effectively removed 53% of oil under inoculation condition. Poor oil removal of below 4% was observed under natural attenuation without inoculation. In addition, it was found that the degradation of oil in oil-polluted soil followed second-order model and acquired the dynamics equations. The half-life of natural attenuation, biostimulation and bioaugmentation was 833 days, 75days, 25days, respectively. The results indicated bioaugmentation could improve efficiently the degradation of TPH and shorten the bioremediation period.

Abstract: pH value is one of the most important factors which affect the nitrogen and phosphorus removal in the wastewater treatment process. The influences of potential of hydrogen on nitrogen and phosphorus removal of wastewater were studied in this study. The results revealed that: (1) faintly acidic environment was conducive to biological phosphorus removal in biochemical reactors with FeCl₃, PFS and PAS but not with Al₂(SO₄)₃.On the other hand, synergistic effect between the microorganism and coagulants ( FeCl₃, PFS, Al₂(SO₄)₃ and PAS) was confirmed in this study. (2) faintly acidic environment was favorable to the nitrogen removal in biochemical reactors with PFS and PAS while the faintly alkaline environment was conducive to the nitrogen removal with FeCl₃ and Al₂(SO₄)₃. And there was no synergistic effect between the microorganism and coagulants.