Effect of Different Influent Conditions on Biomass Production and Nutrient Removal by Aeration Microalgae Membrane Bioreactor (ICFB-MMBR) System for Mariculture Wastewater Treatment

The nutrient removal and biomass production of the internal circulating fluidized bed microalgae membrane bioreactor (ICFB-MMBR) was studied under different cultivation modes, influent TOC, influent pH, and influent N/P. Platymonas helgolandica tsingtaoensis was used as the biological source. The growth of P. helgolandica tsingtaoensis and the removal efficiency of pollutants in the mixotrophy culture mode were improved compared with other culture modes. With the increased influent TOC, the average growth rate of P. helgolandica tsingtaoensis increased, and ammonia nitrogen and total phosphorus removal rate were improved. The P. helgolandica tsingtaoensis growth rate and nutrient removal efficiencies at the influent pH of 8 were the best among the different influent pH values. As the influent N/P ratio increased from 5 to 20, the P. helgolandica tsingtaoensis growth rate and pollutant removal rate increased gradually. When the influent N/P ratio was higher than 20, the P. helgolandica tsingtaoensis growth rate and pollutant removal rate tended to be stable and did not significantly change with the increase of influent N/P ratio. At the proper influent conditions, the high P. helgolandica tsingtaoensis biomass and nutrient removal efficiency could be obtained in the microalgae membrane bioreactor, which could provide a theoretical basis for the application of the system for wastewater treatment.

The coupling of hemin with persistent free radicals induces a nonradical mechanism for oxidation of pollutants

Herein, we report that persistent free radicals (PFRs) based on MWCNTs significantly accelerate the pollutant removal rate.

Kinetic Analysis for COD Removal in Actual Coking Wastewater through an Micro-Aerobic EGSB Reactor

Treatment of actual coking wastewater considered to be difficult by traditional systems. The present study is related to treatment of actual coking wastewater through microaerobic EGSB reactor. The study showed the EGSB reactor could attain about 75% high COD removal. IncreasingVupcould strength COD removal. Moreover, high sludge concentration and profound communal synergism existing within the dense granules were very important. As a result of the kinetic analysis of the EGSB reactor treating actual coking wastewater for COD removal using a modified Stover–Kincannon model, the maximum substrate utilization rate,vmax, half saturation constant,KS, inhibitor constant, KI, actual pollutant removal rate, , and the actual inhibition degree,KS/KIwere determined as 2.65×10-3h-1, 39.57mg.L-1, 415.82mg.L-1, 6.7×10-5h-1.mg-1.L and 0.1(before increasingVup), 7.34×10-3h-1, 19.53mg.L-1, 197.76mg.L-1, 3.7×10-4h-1.mg-1.L and 0.1(after increasingVup), and 9.35×10-3h-1, 6.38mg.L-1, 162.81mg.L-1, 1.47×10-3h-1.mg-1.L and 0.04 (after increasingVupand X), respectively. The inhibition of toxic contaminants in the actual coking wastewater would cause the decreasing of pollutant removal rate, however, enhancing and X (simultaneously optimizing sludge aggregate structure) could strengthen the performance effect.

Kinetic Analysis of COD Removal from Actual Domestic Wastewater in an Expanded Granular Sludge Bed (EGSB) Reactor

Treatment of actual domestic wastewater at ambient temperature, even low temperature is considered to be difficult by traditional systems. The present study is related to treatment of actual domestic wastewater in an EGSB reactor. The study showed the effectiveness of biological treatment of actual domestic wastewater involving appropriate microorganism and granules in an EGSB reactor. At 26°C, the reactor was operated at 18.7kg COD.m−3.d−1 of average organic loading and 83% high COD removal efficiency, and even at the highest loading rate of 57.12kgCOD.m−3.d−1, the COD removal efficiency still could attain to 68%. Varied influent flow need to supply varied optimal and thus to ensure the optimal removal effect. Low temperature would cause pollutant removal rate decrease. However, enhancing could optimize the contact of sludge and wastewater and thus strengthen the performance effect. Modified Stover–Kincannon model was applied to data obtained from experimental studies in EGSB reactor. Treatment efficiencies of the reactor were investigated at different hydraulic retention times (0.5-1.3h) and different operation temperature (15°C, 26°C). The modified Stover–Kincannon model was best fitted to the EGSB reactor, and the substrate utilization rate( ), saturation constant value( ), and actual pollutant removal rate( ) were found to be , , and for 26°C, , , and for 15°C( before increasing ), and , , and for 15°C(after increasing ). Low temperature could cause decrease and thus cause distinct decreasing of COD removal efficiency. However, increasing could increase and accordingly increase COD removal efficiency.

Advanced Treatment of Secondary Sewage Effluent by Iron-Carbon Internal Electrolysis

Due to increasing water scarcity, appropriate technologies were need for advanced treatment of wastewater to enable reuse. Effect of iron-carbon internal electrolysis in tertiary treatment of wastewater was investigated in this study. Static experiment was adopted to evaluate influence of Fe/C ratio, pH, reaction time and aeration on pollutant removal by iron-carbon internal electrolysis. Then dynamic experiment was conducted to determine removal rate of CODcr, TP, chroma and NO3--N. The results showed that internal electrolysis could remove CODcr, TP and chroma efficiently. The optimal ratio of Fe/C was 1:1. Initial pH could affect removal efficiency. In acid circumstance, the removal rate was higher. Degradation reaction by internal electrolysis was fast. when the reaction time was 10min, the removal rate could be ideal. In the process of internal electrolysis, aeration could increase pollutant removal rate. In aerated system, when the reaction time was only 15min, removal rate of CODcr, TP and chroma could reach 49.2%, 89% and 75%. But in non-aerated system, only when the reaction time was 100min could removal rate of these indexes reach 46.5%, 81% and 85.1%. In dynamic experiment, removal rate of CODcr, TP, chroma and NO3- could reach above 40%, 90%, 75% and 20%, respectively.