Continuous self-circulating up-flow granular sludge fluidized bed process treating low-strength real municipal wastewater at high hydraulic loads.

Conditions conducive to aerobic granular sludge (AGS) growth and maintenance are very difficult to realize in continuous-flow biological treatment processes. This study conducted a continuous-flow self-circulating up-flow granular sludge fluidized bed (Zier process) treating real urban wastewater approximately one year. The substantial self-circulating multiple times (R, 8-15 times) and up-flow velocity (8-15 m/h) generated by aeration, the only power equipment in Zier process, facilitated pollutant removal, particle granulation and stabilization.

Novel separate aeration self-circulating technology for continuous aerobic granular sludge process: Performance evaluation, hydrodynamic simulation and control strategy.

The continuous aerobic granular sludge (AGS) process is promising for upgrading existing wastewater treatment facilities. However, this approach is still challenging because of its complicated structure and operation. To address this issue, a novel separate aeration self-circulating technology (abbreviated as Zier) was proposed, which is promising for cultivating AGS by its outstanding upflow velocity and circulation multiplier (more than 30 m/h and 200, respectively).

Innovation for continuous aerobic granular sludge process in actual municipal sewage treatment: Self-circulating up-flow fluidized bed process.

Aerobic granular sludge (AGS) capable of nitrogen and phosphorus removal is mainly limited to the applications in sequencing batch reactors. This study introduced an innovative continuous self-circulating up-flow fluidized bed process (Zier process) using separate aeration. The process was composed of an anoxic column (Zier-A), aeration column (Zier-OO) and aerobic column (Zier-O), and was used to treat actual municipal sewage continuously for 170 days.

One-stage partial nitrification/anammox system with short sludge retention time and low mixed liquor suspended solids long-term control: Establishment, performance and sludge characteristics.

Anammox is a green, economical and efficient nitrogen removal process. Most successful anammox studies are based on biofilm- or granule-based systems, but pure floc sludge partial nitrification (PN) and anammox (A) systems that are not inoculated with anaerobic ammonia oxidizing bacteria (AnAOB) are rarely reported. If the anammox process occurs in floc-based systems, the large specific surface areas provide more efficient nitrogen removal, and are much more economical in terms of construction and investment.

[Effects of External Carbon Sources on Ultimate Nitrogen Removal Performance and Microbial Community in Secondary Effluent Treating Process].

Adding external carbon sources is an important method for advanced nitrogen removal of secondary effluent in wastewater treatment plants (WWTPs). In order to compare the denitrification performance and economy of different carbon sources sufficiently, as well as the effect of long-term addition of carbon sources on the microbial population structure, four single carbon sources (methanol, ethanol, glucose, and sodium acetate) and four types of composite carbon sources were prepared by mixing sodium acetate and ethanol with a higher reaction rate and cheap glucose. The results showed that the effluent (NO-N) concentration of all systems was less than 1.

Emissions, measurement, and control of odor in livestock farms: A review.

Odor emissions from intensive livestock farms have attracted increased attention due to their adverse impacts on the environment and human health. Nevertheless, a systematic summary regarding the characteristics, sampling detection, and control technology for odor emissions from livestock farms is currently lacking. This paper compares the development of odor standards in different countries and summarizes the odor emission characteristics of livestock farms.

Improving the resistance of Anammox granules to extreme pH shock: The effects of denitrification sludge EPS enhanced by a fluctuating C/N ratio cultivation on granules.

This study investigated the effects of denitrification sludge EPS enhanced (DS-EPS) by a fluctuating carbon and nitrogen ratio (C/N) cultivation strategy on the properties of Anammox granules under extreme acid or alkaline shock. The results showed that the DS-EPS significantly improved the nitrogen removal performance of low-density Anammox granular sludge (Granules-) and high-density Anammox granular sludge (Granules) under extreme acid shock (pH 5.0).

[Competitive Selection of Hydroxylamine on Ammonia Oxidizing Bacteria and Nitrite Oxidizing Bacteria].

The effective inhibition of nitrite oxidizing bacteria (NOB) is the key to realizing satisfactory nitrite accumulation and achieving effective nitritation. In order to explore the selective effect of hydroxylamine (NH OH) on ammonia oxidizing bacteria (AOB) and NOB, a sequencing batch reactor (SBR) with the operation mode of anaerobic/aerobic/anoxia (A/O/A) was used to observe the start-up of nitritation at different concentrations and frequencies of NH OH. The results showed that when 5 mg·L of NH OH was added once every 2 cycles, the nitrite accumulation rate (NAR) increased from 0.

[Microbial Diversity of Filamentous Sludge Bulking at Low Temperature].

To investigate the characteristics of microbial diversity during filamentous bulking at low temperature, the induction of sludge bulking was successfully carried out using a low-temperature sequencing batch reactor(SBR). With the help of Illumina MiSeq high-throughput sequencing technology, the overall changes in the microbial community structure of activated sludge, the characteristics of each specific microbial community, and the specific genera were all investigated under different sludge sedimentation performances. The results showed that filamentous bulking can be successfully induced after the system operating temperature drops to (14±1)℃, and the COD and TN removal rates can still be maintained at approximately 90% and 86%, respectively, with the sludge volume index deteriorating to 663.

[Effect of Free Hydroxylamine on the Activity of Two Typical Nitrite-oxidizing Bacteria].

The sludge from enrichment of and was used as a research object and batch tests were performed. The inhibitory effects of hydroxylamine on and under the same pH and different hydroxylamine concentration gradients, the same hydroxylamine concentration, and different pH gradients were investigated. The results showed that under the same pH condition, the activity of decreased with increasing hydroxylamine concentration.

[Effect of Alkaline Sludge Fermentation Products on the Nitrification Process and Performance].

The aim of the present study was to investigate the effect of alkaline sludge fermentation products as a carbon source on the nitrification process and performance. During the operation of a biological nitrogen removal (BNR) system with sludge fermentation mixture as the carbon source, the activities of ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) were inhibited at the beginning. After 16 days, the activity of AOB began to recover rapidly, but the activity of NOB was still inhibited.

[Advanced Nitrogen Removal Characteristics of Low Carbon Source Municipal Wastewater Treatment via Partial-denitrification Coupled with ANAMMOX].

Partial-denitrification coupled with ANAMMOX is a novel biological nitrogen removal technology, which is expected to significantly reduce the external carbon source dosage for advanced nitrogen removal from municipal wastewater. In this study, ANAMMOX sludge was inoculated to investigate advanced nitrogen removal performance and sludge characteristics in a partial-denitrification/ANAMMOX reactor. The results showed that inoculation of ANAMMOX sludge could quickly start the partial-denitrification/ANAMMOX reactor.

[Removal of Hydrogen Sulfide Produced in a Municipal WWTP Using a Biotrickling Filter with Polypropylene Rings as the Packing Material and Microbial Community Analysis].

Under transient conditions, a biotrickling filter was developed to treat gaseous HS produced from the fine-grid reservoir of a municipal wastewater treatment plant (WWTP) with AAO excess sludge as the inoculum and polypropylene rings as the packing material. The start-up process and steady-state operation of the biotrickling filter were studied. With an empty bed retention time of 14 s, an ambient temperature of 7.

[Realization of Limited Filamentous Bulking with Type 0092 Filamentous Bacteria as the Dominant Filamentous Bacteria in Shortcut Nitrification].

Type 0092 filamentous bacteria generally do not result in excessive sludge bulking. To take advantage of this, domestic sewage was used to inoculate shortcut nitrification sludge in a sequencing batch reactor (SBR). Sludge settleability, the nitrite accumulation ratio (NAR), pollutant removal characteristics, and the dynamic variation of microbial communities during the system startup and maintenance were investigated.

[Advanced Denitrification of Municipal Wastewater Achieved via Partial ANAMMOX in Anoxic MBBR].

Anoxic MBBR is a process to achieve advanced denitrification from municipal wastewater. Here, anoxic MBBR was applied as a post-denitrification SBR to achieve advanced denitrification by partial anammox (anaerobic ammonium oxidation). During a 250-day operation, denitrification performance gradually improved and the total nitrogen concentration of the effluent was approximately 5 mg·L.

[Effect of Cu on Denitrification Using NO as an Electron Acceptor].

The short-cut biological nitrogen removal process has been widely used in industrial wastewater treatment, and denitrification is a crucial step for removing nitrogen on which the effect of Cu, a common heavy metal ion in wastewater, has not been studied. In this study, sludge with good short-range biological nitrogen removal characteristics in an A/O reactor was selected to investigate the short-term and long-term effects of Cu on denitrification using NO as an electron acceptor. The results showed that Cu had a significant inhibitory effect on denitrification process using NO as an electron acceptor, and the semi-inhibitory concentration EC of sludge activity was 4.

[Performance of the Removal of Nitrogen During Anaerobic Ammonia Oxidation Using Different Operational Strategies].

The effects of low substrate ratio, cooling methods, and pH on nitrogen removal performance were studied in a laboratory-scale anaerobic ammonium oxidation reactor (ASBR) while treating simulated domestic waste water. The results illustrated that the average removal efficiencies of NH-N and NO-N increased from 54.4% and 65.

[Identification and Nitrogen Removal Characteristics of the Heterotrophic Nitrification and Aerobic Denitrification Bacterial Strain DK1].

Nitrogen removal by a newly discovered sp. strain, DK1, isolated from activated sludge was investigated. Using glucose as a carbon source and a (C)/(N) ratio of five, batch experiments showed that the aerobic denitrification removal rate was 4.

[Effects of Temperature on Shortcut Nitrification and Nitrification Activity of Nitrification in an Intermittent Aeration Sequencing Batch Reactor].

Real domestic sewage was treated with sequencing batch reactors (SBR). The aerobic/anoxic modes were alternated 4 times at 30℃ and 7 times at 18℃ in a single-cycle, respectively, and the ratio of aerobic/anoxic cycles was 30 min/30 min. The influent concentration of ammonia and nitrite was 61.

[Effect of Step Feed on Denitrifying Phosphorus and Nitrate Removal in a Modification of the Two Sludge A/O-BAF System].

A modification of the two sludge A/O-BAF system was used to treat low C/N real domestic sewage. In order to improve the utilization of the carbon source, the effects of two step feeds (pre-anoxic zone and anoxic zone) on denitrifying phosphorus and nitrate removal were studied. According to the formula of material balance for COD, the utilization of carbon source was analyzed and evaluated under different ratios of step feed, simultaneously.

[Effect of Aeration Rate on Shortcut Nitrification Recovery in Intermittent Aeration Mode].

Shortcut nitrification sludge, which was set aside for two months, was recovered using Reactors Ⅰ, Ⅱ, Ⅲ, and Ⅳ. The aeration rates of Reactors Ⅰ, Ⅱ, Ⅲ, and Ⅳ were 120, 100, 80, and 60 L·h, respectively, while treating real domestic sewage, and the ratio of aerobic/anoxic was 30 min/30 min at the temperature of 25℃. The influent of ammonia was 50-80 mg·L, and the concentration of effluent ammonia was stable, at below 5 mg·L, after the 12, 18, 21, and 21 cycles.

[Effect of Free Ammonia on Ammonia Escape During an Ammonia Oxidation Process].

This study used short process nitrification sludge to investigate the effect of high free ammonia (FA) on ammonia escape during ammonia oxidation. A sequencing batch reactor (SBR) was used to study the ammonia escape process under different FA concentrations. The results indicate that FA in water is usually combined with water molecules at lower FA concentrations to produce stable NH·HO with almost no ammonia escape.

Cr(VI) Adsorption on Red Mud Modified by Lanthanum: Performance, Kinetics and Mechanisms.

Water pollution caused by the highly toxic metal hexavalent chromium (Cr(VI)) creates significant human health and ecological risks. In this study, a novel adsorbent was used to treat Cr(VI)-containing wastewater; the adsorbent was prepared using red mud (RM) generated from the alumina production industry and the rare earth element lanthanum. This study explored adsorption performance, kinetics, and mechanisms.

Effects of carbon sources on the enrichment of halophilic polyhydroxyalkanoate-storing mixed microbial culture in an aerobic dynamic feeding process.

Microbial polyhydroxyalkanoate (PHA) production serves as a substitute for petroleum-based plastics. Enriching mixed microbial cultures (MMCs) with the capacity to store PHA is a key precursor for low-cost PHA production. This study investigated the impact of carbon types on enrichment outcomes.