Electrochemically mediated phosphorus and energy recovery from digested effluent.

The growing global concern over the high phosphorus concentration in discharged wastewaters has driven the demand for exploring the means to recover it from wastewater. We previously demonstrated the possibility of phosphorus recovery by iron-air fuel cells from digested effluent. The present study focused on further optimizing the performance of the fuel cell by adjusting the wastewater properties (initial pH) and device parameters (anode/cathode area ratio, electrode spacing).

Applying sheet iron to enhance the treatment efficiency of digested effluent with continuous flow and the corresponding mechanism.

Because of the unstable wastewater quantity and quality, the biological treatment efficiency of digested effluent was not as expected. A convenient and effective way was eagerly required to improve the efficiency of biological treatment. By sheet iron addition (R), the COD and TN removal efficiencies under continuous flow condition increased by 59% and 37% respectively.

Condition optimization of iron-air fuel cell to treat phosphate-containing wastewater regarding sustainable development.

Increasing use of phosphorus products and excessive exploitation of phosphorus resources become two major problems in perspective of phosphorus sustainable development. Phosphorus recovery is the shortcut to solve this dilemma. Combining electrochemistry, an iron-air fuel cell was adopted to recover phosphate and electricity from phosphate-containing wastewater in our previous studies.

Analyzing the mechanism of nitrous oxide production in aerobic phase of anoxic/aerobic sequential batch reactor from the perspective of key enzymes.

How the vast majority of nitrous oxide (NO) in the aerobic zone of nitrogen bio-removal process is produced is still a controversial issue. To solve this issue, this study measured the activities of two key denitrifying enzymes (nitric oxide reductase (Nor) and nitrous oxide reductase (NOR)) in an A/O SBR with different chemical nitrogen demand (COD)/total nitrogen (TN) ratios. By analyzing the Spearman's correlations between the NO production, the enzyme activities, and the factors, the main NO production process was identified.

An iron-air fuel cell system towards concurrent phosphorus removal and resource recovery in the form of vivianite and energy generation in wastewater treatment: A sustainable technology regarding phosphorus.

Phosphorous (P) recovery from industrial wastewaters solves both P deficiency and P pollution problems. A sequencing batch iron-air fuel cell was set up to recover P from synthetic wastewater containing 0.6 g-P/L NaHPO.

[Effect of an Aerobic Unit and a Sedimentation Unit on Sludge and Nitrogen Removal in an Anoxic Unit in a Continuous-flow System].

Using an A/O process with three dissolved oxygen (DO) levels[3.0-3.5 mg·L(Ⅰ stage), 2.

[Effect of Organic Characteristics on Sludge Settleability in an AAO System].

The effects of different mixed organic matter ratios on sludge settleability were examined from the succession patterns of microbial community structure, and changes of microbial intracellular and extracellular polymers in the activated sludge. The experimental results showed that when organic matter was dissolved in the influent, the sludge settleability was optimal (SVI=70 mL·g), which was better than that for influent water with partially dissolved organic matter (SVI=120 mL·g) and particulate organic matter (SVI=280 mL·g). According to the analysis of microbial community structure, , , and were important in influencing the sludge settleability.

[Operational Performance and Microbiological Characteristics of an Iron-Salt Denitrification Reactor in Co-substrate Mode].

When iron salt is used as an autotrophic denitrification electron donor, the high iron yield generated by oxidation is easy to precipitate, resulting in "iron encrustation" on the surface of denitrifying microorganisms, which inhibits their activity and even leads to their death. In order to solve the degradation of the efficiency of the autotrophic ferric denitrification reactor caused by the "iron encrustation" coating, this paper adopted the co-substrate mode to cultivate the ferric denitrification reactor; that is, a small amount of sodium acetate was added into the water of the reactor as an organic electron donor, to realize the efficient and stable operation of the ferric denitrification reactor. The results showed that adding an appropriate amount of organic matter could make the iron salt denitrification reactor run efficiently and stably, with an efficiency of up to 0.

[Effect of Microbial Community Structure and Metabolites on Sludge Settling Ability Under Three Different Switching Condition Processes].

Using sodium acetate as the carbon source, sludge settling ability (settleability) was investigated under three processes:AAO nitrogen and phosphorus removal(process Ⅰ), AO nitrification-denitrification (process Ⅱ), and aerobic carbon removal (process Ⅲ). The succession of microbial community structures in sludge was traced, the content and composition of microbial metabolites were monitored, and the effects of operational mode on sludge settleability were analyzed. The results showed that the settleability of process Ⅰ was the best, followed by process Ⅲ and Ⅱ.

CFD Simulation of flow pattern in a bubble column reactor for forming aerobic granules and its development.

The flow pattern is considered to play an important role in the formation of aerobic granular sludge in a bubble column reactor; therefore, it is necessary to understand the behavior of the flow in the reactor. A three-dimensional computational fluid dynamics (CFD) simulation for bubble column reactor was established to visualize the flow patterns of two-phase air-liquid flow and three-phase air-liquid-sludge flow under different ratios of height to diameter (H/D ratio) and superficial gas upflow velocities (SGVs). Moreover, a simulation of the three-phase flow pattern at the same SGV and different characteristics of the sludge was performed in this study.

NO Emission and Hydroxylamine Oxidase (HAO) Activity in a Nitrogen Removal Process Based on Activated Sludge with Three COD/NH Ratios.

  This study dealt with nitrous oxide (N2O) emission and hydroxylamine oxidase (HAO) activity of waste sludge in a nitrification and denitrification process employing three carbon nitrogen (C/N) ratios in a sequencing batch reactor (SBR). The experimental results indicated that N2O emission increased dramatically after the C/N ratio in the sludge increased from 6.5 to 9.

[Application of FCM-qPCR to Quantify the Common Water Pathogens].

In the past, fecal E. coli was always regarded as the indicator organism for estimation of pathogens in water. However, a weak relation between fecal E.

[Achievement of Sulfate-Reducing Anaerobic Ammonium Oxidation Reactor Started with Nitrate-Reducting Anaerobic Ammonium Oxidation].

The transformation of nitrite-reducing anaerobic ammonium oxidation to sulfate-reducing anaerobic ammonium oxidation in an UASB was performed and the changes in microbial community were studied. The result showed that the sulfate reducing anaerobic ammonium oxidation process was successfully accomplished after 177 days' operation. The removal rate of ammonium nitrogen and sulfate were up to 58.

[Application of FISH-NanoSIMS technique in environmental microbial ecology study].

With the development of microbial ecology techniques, it is possible to analyze the distribution and function of microorganisms simultaneously in complex ecosystems. To explore the application of FISH-NanoSIMS in environmental microbial ecology study, our study used the stable isotope labeled compounds 13C-C6H12O6, and 15N-NH4Cl as C and N sources for cultivating the pure culture (manganese oxidizing bacteria, Pseudomonas sp. QJX-1) and environmental samples (the shallow soil and anaerobic sludge).

Phosphorus metabolism and population dynamics in a biological phosphate-removal system with simultaneous anaerobic phosphate stripping.

In this study, the metabolism of phosphorus and changes in population dynamics were investigated via simultaneous chemical stripping in sidestream in an acetate-fed sequencing batch reactor. The synthesized intracellular polyphosphate (poly-P) by polyphosphate-accumulating organisms (PAOs) gradually decreased when the biomass was subjected to 83 d of P stripping. Initially, the P removal efficiency of the system improved from 94.

[Characterization of manganese oxidation by Pseudomonas sp. QJX-1].

A manganese-oxidizing bacteria (QJX-1) was isolated from the soil of a manganese mine. It was identified as Pseudomonas sp. QJX-1 by 16S rDNA sequencing.

[Influence of buffer solutions on the performance of microbial fuel cell electricity generation].

Microbial fuel cell (MFC) is a potential green technology due to its application in wastewater treatment and renewable energy generation. Phosphate buffer solution (PBS) has been commonly used in MFC studies to maintain a suitable pH for electricity generating bacteria and/or to increase the solution conductivity. However, it has some drawbacks using PBS in MFC: One is that the addition of a high concentration of phosphate buffer in MFCs is expensive, especially for the application in wastewater treatment; the other is that phosphates can contribute to the eutrophication conditions of water bodies if the effluents are discharged without the removal of phosphates.

[Enhanced biological phosphorus removal in single aerobic process].

When SBR with sodium acetate as the sole carbon source and operated under alternative anaerobic and aerobic condition had achieved a good performance in phosphate removal, it was shifted to completely aerobic treatment system, and found that a good phosphorus removal with removal efficiency of the highest of 73.9%, the lowest of 40% and an average of about 50% was still achieved. The phosphate removal could last 80 cycles before regeneration.

[Relationship between phosphorus content in activated sludge and sludge bulking in biological nutrient removal SBR systems].

In order to investigate the relationship among phosphorus content of sludge, filamentous bacteria and sludge settleability, two sets of Sequencing Batch Reactor (SBR) inoculated activated sludge that had different dominant filamentous bacteria and fed with synthetic wastewater were operated in A2/O process. Phosphorus concentration in influent was increased from 10 mg/L to 30 mg/L. Result showed that with increase of phosphorus in influent from 10 mg/L to 20 mg/L and 30 mg/L, phosphorus content of the sludge in reactor No.

[Improvement of denitrifying dephosphatation in an anaerobic/anoxic sequencing batch reactor and its stability].

An anaerobic/anoxic sequencing batch reactor (A/A SBR) was conducted to investigate the conditions for screening and enrichment of denitrifying phosphorus removing bacteria (DPB). The results showed that, when the concentration of COD in influential of anaerobic stage, the concentration of NO3 -N in influent of anoxic stage and pH value were 300 mg/L, 50 mg/L and 7.0 respectively, DPB could become dominant populations quickly in the system in two-time feeding mode, and the reactor performed well for denitrifying phosphorus removal.

[Experiment of simultaneous denitrifying phosphorus accumulation].

Denitrifying phosphorus accumulation (DNPA) and the factors affecting it were studied in a SBR with synthetic wastewater. The results showed that the sludge acclimatized under anaerobic/aerobic operation with good phosphorus removal ability, showed DNPA soon when fed nitrate instead of aeration following the anaerobic stage. Anaerobic stage was a vital premise to DNPA.

Promoting nitrification by using functional gel as immobilizing medium under different temperature stimulation patterns.

Nitrification with nitrifiers immobilized by temperature stimuli-responsive N-isopropylacrylamide-Chlorophyll (NIPA-CH) gel was investigated under several patterns of temperature stimulation, compared with that at constant temperature. The results show that in response to a cyclic temperature stimulus of 32-36 degrees C or 32-34 degrees C with a period of 4 or 2 h, respectively, the gel swelled and shrank reversibly and promoted biological nitrification. But in the case of a cyclic temperature change of 32-36 degrees C with a stimulation cycle of 2 h, nitrite oxidization declined.