[Characteristics of Partial Denitrification in Biofilm System].

As an intermediate form of microbial denitrification, nitrite serves as a key substrate for anaerobic ammonium oxidation (ANAMMOX). This study investigated the partial dentification (PD) characteristics and the coupling feasibility of PD+ANAMMOX in the biofilm system, using a moving bed biofilm reactor which was operated for 120 days. After 40 days of operation with a C/N ratio of 3.

[Treatment of Medium Ammonium Wastewater by Single-stage Partial Nitritation-ANAMMOX SMBBR].

A SMBBR was established to treat medium ammonium under room temperature. Results showed that TN load can reach 0.16 kg·(m·d), and the average TN removal efficiency was (51.

[Adaptability of Nitrifying Biofilm Systems to Low Temperature: MBBR and IFAS].

The long-term effects of a decreasing temperature on the nitrification performance, biofilm characteristics, and nitrifier community in a moving-bed biofilm reactor (MBBR) and integrated fixed-film activated sludge (IFAS) system were investigated at various temperatures (20, 15, and 10℃) to explore the adaptability of nitrifying biofilm systems to low temperatures. During the experiment, the extracellular polymeric substances (EPS) in the biofilms increased with decreasing temperature, which resulted in an increased biofilm mass and thickness. As there was only a biofilm phase in the MBBR to remove ammonia, the part of the carriers in the MBBR at 10℃ became plugged, which partially led to a deterioration in the effluent water quality.

Insight into the fenton-induced degradation process of extracellular polymeric substances (EPS) extracted from activated sludge.

Although EPS in microbial aggregates are importance in successful implementation of biological wastewater treatment systems, they also exhibit detrimental role on certain circumstance, such as excess sludge dewatering. Extensive efforts have been put into the disruption of EPS for improving the dewaterability of excess sludge and Fenton's reagent treatment has been demonstrated to be a very promising sludge conditioning method for EPS destruction. However, the information regarding detailed degradation process of EPS during Fenton's reagent treatment is limited.

[Influence on Desulfurization Efficiency and Interactions of Fe/S and pH During HS in situ Depression of High Solid Anaerobic Digestion].

To evaluate the influence of Fe/S ratio and pH on sulfide removal efficiency and interactions between Fe/S and pH, anaerobic hydrogen sulfide in situ depression tests and digested sludge liquor sulfide removal tests were carried out by using dewatering sludge from a wastewater treatment plant (WWTP). Results showed that the concentration of hydrogen sulfide in biogas from the thermal pretreatment following anaerobic digestion process could be reduced from 170.4×10 to 14.

[Effect of Temperature on PAO Activity and Substrate Competition].

To investigate the effect of temperature on the activity of high-temperature phosphate accumulating organisms (PAO) and their competitive ability for the substrate, the sludge from an enhanced biological phosphorus removal (EBPR) reactor stably operated at the high temperature of 30℃ was used. The results showed that PAO activity and their competitive ability for the substrate increased with temperature increasing from 15℃ to 30℃. When the temperature was as higher as 30℃, the rates of anaerobic phosphorus release, aerobic phosphorus uptake and acetate uptake of PAO were 239.

[Fast Start-up of ANAMMOX and the Spatial Distribution of EPS in ANAMMOX Granules].

An anaerobic sequencing batch reactor(ASBR) inoculated with activated sludge was employed to investigate the start-up of anaerobic ammonium oxidation(ANAMMOX) process and the spatial distribution of extracellular polymeric substances(EPS) in ANAMMOX granules. The results showed that the removal rates of NH-N and NO-N reached more than 99%. The removal rate of total nitrogen(TN) was 89.

[Enrichment of in Activated Sludge and Kinetic Characterization].

was enriched from activated sludge by using fed-batch cultivation, and its related kinetic characterization was studied. The results showed that could be successfully enriched from the activated sludge for a controlled nitrite concentration no higher than 2 mg·L. The maximum nitrate oxidation rate was 48.

Composition and functional group characterization of extracellular polymeric substances (EPS) in activated sludge: the impacts of polymerization degree of proteinaceous substrates.

Characteristics of extracellular polymeric substances (EPS) in activated sludge strongly depend on wastewater substrates. Proteinaceous substrates (ProS) present in heterogeneous polymeric form are intrinsic and important parts of wastewater substrates for microorganisms in activated sludge systems. However, correlations between ProS and characteristics of EPS are scarce.

[Comparison of Operating Performance of Partial Nitritation Systems with Two Different Inhibition Strategies].

Two SBRs which were under high ammonia loading[1 kg·(m·d)] and different dual inhibition with feed-batch were employed to study how to control the stability of partial nitritation system. The experimental result showed that the dual inhibition of FNA and DO or FA and DO could implement partial nitrification process at 35℃±1℃ and the ammonia concentration of 1000 mg·L. The effluent NO-N/NH-N ratio was about 1, and the effluent NO-N concentration was close to 0, which was suitable for the appropriate influent for the ANAMMOX.

[Non-CO Greenhouse Gas Release from Different Biological Wastewater Treatment Processes].

Methane (CH) and nitrous oxide (NO) are two of the most important non-CO greenhouse gases. And municipal sewage treatment plant is an important anthropogenic source of CH and NO. Therefore, it is essential to measure the production and emission of CH and NO during biological wastewater treatment process.

Is polymeric substrate in influent an indirect impetus for the nitrification process in an activated sludge system?

Different from monomeric substrate, polymeric substrate (PS) needs to undergo slow hydrolysis process before becoming available for consumption by bacteria. Hydrolysis products will be available for the heterotrophs in low concentration, which will reduce competitive advantages of heterotrophs to nitrifiers in mixed culture. Therefore, some links between PS and nitrification process can be expected.

Nitrite oxidizing bacteria (NOB) dominating in nitrifying community in full-scale biological nutrient removal wastewater treatment plants.

Nitrification activities and microbial populations of ammonium oxidizing bacteria (AOB) and nitrite oxidizing bacteria (NOB) were investigated in 10 full-scale biological nutrient removal wastewater treatment plants in Xi'an, China. Aerobic batch tests were used to determine the nitrifying activities while fluorescence in situ hybridization was used to quantify the fractions of AOB and NOB in the activated sludge. The results showed that nitrifying bacteria accounted for 1-10% of the total population.

[Community Structure and Activity Analysis of the Nitrifiers in Raw Sewage of Wastewater Treatment Plants].

The communities and activity of nitrifiers collected from the raw sewage of the 2 and 3 wastewater treatment plants (WWTP) in Xi'an were investigated. FISH results indicated that the (AOB+NOB)/EUB percentages were (5.35±2.

[Effects of carbon sources, temperature and electron acceptors on biological phosphorus removal].

Effects of carbon sources, temperature and electron acceptors on phosphorus uptake and release were investigated in a pilot-scale oxidation ditch. Phosphorus uptake and release rates were measured with different carbon sources (domestic sewage, sodium acetate, glucose) at 25 degrees C. The results showed that the minimum phosphorus uptake and release rates of glucose were 5.

[Transformation characteristics of carbon, nitrogen, phosphorus and sulfur during thermal hydrolysis pretreatment of sludge with high solid content].

The transformation characteristics of carbon, nitrogen, phosphorus and sulfur in dewatering sludge from municipal wastewater treatment plant (WWTP) were investigated after thermal hydrolysis pretreatment at 165 degress C for 50 min. The results showed that the hydrolysis efficiency of VSS could reach as high as 43.35%, 54.

Nutrient release, recovery and removal from waste sludge of a biological nutrient removal system.

The uncontrolled release of nutrients from waste sludge results in nitrogen and phosphorus overloading in wastewater treatment plants when supernatant is returned to the inlet. A controlled release, recovery and removal of nutrient from the waste sludge of a Biological Nutrient Removal system (BNR) are investigated. Results showed that the supernatant was of high mineral salt, high electrical conductivity and poor biodegradability, in addition to high nitrogen and phosphorus concentrations after the waste sludge was hydrolysed through sodium dodecyl sulphate addition.

A new classification paradigm of extracellular polymeric substances (EPS) in activated sludge: separation and characterization of exopolymers between floc level and microcolony level.

Extracellular polymeric substances (EPS) play a crucial role in the formation of activated sludge flocs. However, until now, the EPS are rather classified by the method used for extraction than by a theoretical consideration of their function and composition. In this paper, a new classification paradigm of EPS was proposed, which offered a novel approach to identify the role of EPS in the formation of activated sludge flocs.

The important implications of particulate substrate in determining the physicochemical characteristics of extracellular polymeric substances (EPS) in activated sludge.

Since the notable amount of particulate substrate in wastewater, the implications of particulate substrate on treatment efficiency have been a topic of major interest in the field of biological wastewater treatment. The particulate substrate has to be hydrolyzed by the extracellular enzymes, which are mainly embedded in extracellular polymeric substances (EPS) matrix of microbial aggregates, prior to consumption. Therefore, the important relevance between the particulate substrate and the characteristics of EPS can be expected.

Hydrogen utilization rate: A crucial indicator for anaerobic digestion process evaluation and monitoring.

Hydrogenotrophic methanogens had been considered as key species for the anaerobic digestion (AD) of industrial wastewater and municipal sludge. However, how to evaluate the activity of the hydrogenotrophic methanogens was less studied. In this study, a volumetric device and a test procedure were developed for measuring the specific hydrogen utilization rate (HUR) of anaerobic sludge.

Nitrogen-removal performance and community structure of nitrifying bacteria under different aeration modes in an oxidation ditch.

Oxidation-ditch operation modes were simulated using sequencing batch reactors (SBRs) with alternate stirring and aerating. The nitrogen-removal efficiencies and nitrifying characteristics of two aeration modes, point aeration and step aeration, were investigated. Under the same air-supply capacity, oxygen dissolved more efficiently in the system with point aeration, forming a larger aerobic zone.

[Optimization and comparison of nitrogen and phosphorus removal by different aeration modes in oxidation ditch].

The oxidation ditch operation mode was simulated by sequencing batch reactor (SBR) system with alternate stirring and aeration. The nitrogen and phosphorus removal efficiencies were investigated in two different aeration modes: point aeration and step aeration. Experimental results show that oxygen is dissolved more efficiently in point aeration mode with a longer aerobic region in the same air supply capacity, but dissolved oxygen (DO) utilization efficiency for nitrogen and phosphorus removal is high in step aeration mode.

[Formation of the phosphorus removal granular sludge and phosphorus removal characteristics of the anaerobic/oxic and anaerobic/anoxic/oxic granular sludge process in SBR].

Phosphorous removal & denitrifying phosphate uptake of the granular sludge was investigated in this study. Inoculated with flocculation sludge, the granulation of the biological phosphorous removal sludge was realized in a sequencing batch reactor (SBR) fed with sodium acetate by means of hydraulic selection under an anaerobic/oxic alternating operation (referred to as an A/O). Then the biological phosphorous removal granular sludge was induced into the denitrifying phosphate uptake granular sludge under an anaerobic/anoxic/oxic alternating operation (referred to as an A/A/O).

[Community structure and kinetics characterization of enriched nitrifiers cultivated with reject water].

The community of nitrifiers cultivated with reject water were investigated by fluorescent in situ hybridization (FISH) performed with 16S rRNA-targeted oligonucleotide probes, and the kinetic properties such as temperature correction factor tauN and the half saturation coefficient K(N) were also investigated. The results showed that the percentage of ammonia oxidizing bacteria (AOB) and nitrite oxidizing bacteria (NOB) in the activated sludge was 15.7% +/- 3.

[Effects of F/M on the uptake, storage and utilization of carbonhydrate in ASBR].

Substrate utilization in a glucose-fed anaerobic sequencing batch reactor (ASBR) under different F/M ratios was investigated. Glucose added was quickly taken up by fermentation bacterial in anaerobic digestion, then partly degraded directly to volatile fatty acid (VFA, accounted for 34%-38% of COD-fed) and partly accumulated transiently in the cell as glycogen (accounted for 41%-46% of COD-fed) and degraded to VFA in the following. The bacterial accumulation capacities increased with F/M.