Elucidation of the stress mechanisms on activated sludge stability induced by yttrium oxide nanoparticles with cytotoxicity: Performance deterioration, biointerface variation and microbial response.

As technoscience advances, widespread use of nanoparticles (NPs) has resulted in environmental risks. This study focuses on the potential stress of 0-200 mg/L yttrium oxide (YO) NPs on the activated sludge stability. YO NPs progressively suppressed nitrification, caused significant NO accumulation (200 mg/L) and diminished activities of key functional enzymes.

Roles of quorum-sensing molecules in methane production from anaerobic digestion aided by biochar.

Biochar has been used to enhance methane generation from anaerobic digestion through establishing direct interspecific electron transfer between microorganisms. However, the microbial communication is still inadequate, thereby limiting further methane production improvement contributed by biochar. This study investigated the roles of quorum-sensing molecules, acylated homoserine lactone (AHL), in anaerobic digestion of waste activated sludge aided by biochar.

Biochar alleviates inhibition effects of humic acid on anaerobic digestion: Insights to performances and mechanisms.

To recover methane from waste activated sludge through anaerobic digestion (AD) is one promising alternative to achieve carbon neutrality for wastewater treatment plants. However, humic acids (HAs) are one of the major compositions in waste activated sludge, and their accumulation performs inhibition effects on AD. This study investigated the potentials of biochar (BC) in alleviating inhibition effects of HAs on AD.

Biochar derived from alkali-treated sludge residue regulates anaerobic digestion: Enhancement performance and potential mechanisms.

Biochar produced from bio-wastes has been widely used to promote the performance of anaerobic digestion. Waste activated sludge (WAS) is considered as a kind of popular precursor for biochar preparation, but the abundant resources in WAS were neglected previously. In this study, the roles of biochar prepared from raw, pretreated, and fermented sludge on anaerobic digestion were investigated.

Natural zeolite enhances anaerobic digestion of waste activated sludge: Insights into the performance and the role of biofilm.

Anaerobic digestion is widely employed for the treatment of waste activated sludge (WAS) due to its advantages like simultaneous energy recovery and sludge stabilization, promoting carbon-neutral operation of wastewater treatment plants. Natural zeolite, a low-cost and eco-friendly additive, has the potential to improve methane production from anaerobic digestion. This study investigated the effects of natural zeolite on anaerobic digestion when the substrate was WAS.

Positive responses and mechanisms of nitrifying sludge to carbon quantum dots: reactor performance, microbial behavior, and antioxidant defense.

Extensive application of carbon quantum dots (CQDs) enlarges its concentration in sewage treatment system. The response of nitrifying sludge to CQDs after long-term exposure was investigated. Results showed that CQD concentrations of 0-100 mg/L presented positive effect to enzymes involved in nitrification, accelerating NH-N degradation and NO-N transformation.

Insights into the roles and mechanisms of a green-prepared magnetic biochar in anaerobic digestion of waste activated sludge.

Methane is one of the most promising renewable energies to alleviate energy crisis or replace fossil fuels, which can be recovered from anaerobic digestion of bio-wastes. However, the engineering application of anaerobic digestion is always hindered by low methane yield and production rate. This study revealed the roles and mechanisms of a green-prepared magnetic biochar (MBC) in promoting methane production performance from waste activated sludge.

Insights into response mechanism of anaerobic digestion of waste activated sludge to particle sizes of zeolite.

Anaerobic digestion has been proved as one promising strategy to simultaneously achieve resource recovery and environmental pollution control for biosolid treatment, and adding exogenous materials is a potential alternative to promote the above process. This study investigated response mechanisms of anaerobic digestion of waste activated sludge (WAS) to particle sizes of zeolite. Results showed that the methane production reached 186.

The nutrient removal and tolerance mechanism of a heterotrophic nitrifying bacterium Pseudomonas putida strain NP5 under metal oxide nanoparticles stress.

The occurrence of metal oxide nanoparticles (NPs) in wastewater treatment plants (WWTPs) has raised great concerns about their adverse impacts on nitrification performance. In this study, a heterotrophic nitrifying bacterium Pseudomonas putida strain NP5 showed strong resistance against TiO and NiO NPs. Under 5-50 mg/L NP stress, cell viability was still normal, and the final nutrient removal rates, always higher than 80%, were slightly inhibited.

Response of anaerobic digestion of waste activated sludge to types of alkalis: Contribution identification of metal ions.

Alkaline pretreatment is one promising strategy for promoting anaerobic digestion of waste activated sludge (WAS). This study selected three types of alkalis with monovalent (NaOH and KOH), divalent (Ca(OH) and Mg(OH)), and trivalent (Fe(OH) and Al(OH)) cations to reveal the roles of metal ions on short chain fatty acids (SCFAs) production. The enhanced production potentials of SCFAs were reduced by order of alkalis with monovalent, divalent, and trivalent cations.

Roles of zero-valent iron in anaerobic digestion: Mechanisms, advances and perspectives.

With the rapid growth of population and urbanization, more and more bio-wastes have been produced. Considering organics contained in bio-wastes, to recover resource from bio-wastes is of great significance, which can not only achieve the resource recycle, but also protect the environment. Anaerobic digestion (AD) has been proved as one of the most promising strategies to recover bio-energy from bio-wastes, as well as to realize the reduction of bio-wastes.

Potassium ferrate followed by alkali-stripping treatment to achieve short-chain fatty acids and nitrogen recovery from waste activated sludge.

Waste activated sludge (WAS) is a potential resource to achieve carbon-neutral goal of wastewater treatment plant. However, the solubilization is always the rate-limiting step for resource recovery from anaerobic digestion of WAS. This study reported a novel strategy, i.

Role and significance of water and acid washing on biochar for regulating methane production from waste activated sludge.

Methane recovered from anaerobic digestion of waste activated sludge (WAS) can be used as the energy supplement of the wastewater treatment plant, benefiting to its carbon-neutral operation. In order to enhance methane production, biochar (BC) has been widely selected as conductive material to build direct interspecies electron transfer (DIET) in anaerobic digestion of WAS. However, the role and significance of washing strategies, including water and acid washing, on BCs for regulating methane production have not been reported.

Stepwise freezing-thawing treatment promotes short-chain fatty acids production from waste activated sludge.

Waste activated sludge (WAS), as the byproducts of wastewater treatment plants, has been greatly produced. With high cost and environmental risk of WAS disposal, to explore a low-cost and environment-friendly technology has been a great challenge. Considering that WAS is a collection of organic matters, anaerobic fermentation has been selected as a sustainable way to simultaneously recover resources and reduce environmental pollution.

Freezing-low temperature treatment facilitates short-chain fatty acids production from waste activated sludge with short-term fermentation.

This study proposed a novel and high-efficiency strategy, i.e., freezing followed by low-temperature thermal treatment, to significantly promote short-chain fatty acids (SCFAs) production from waste activated sludge compared to traditional freezing/thawing treatment.

Stepwise alkaline treatment coupled with ammonia stripping to enhance short-chain fatty acids production from waste activated sludge.

To recover resource from waste activated sludge (WAS) is of great significance. This study proposed a promising way, i.e.

Responses of anaerobic digestion of waste activated sludge to long-term stress of benzalkonium chlorides: Insights to extracellular polymeric substances and microbial communities.

Quaternary ammonium compounds have gained widespread attention due to their extensive enrichment in waste activated sludge (WAS) and potentially adverse effect to anaerobes. This study selected benzalkonium chlorides (BACs) as model to reveal the responses of anaerobic digestion of WAS to long-term stress of BACs. Results showed that the solubilization enhancement of WAS contributed by BACs was the acceleration of cell lysis, rather than the disruption of extracellular polymeric substances, and the accumulation improvement of short chain fatty acids (SCFAs) attributed to hydrolysis improvement and methanogenesis inhibition at either medium -or high level of BACs.

Occurrence, effect, and fate of residual microplastics in anaerobic digestion of waste activated sludge: A state-of-the-art review.

The plastic products have large consumption over last decades, resulting in a serious microplastics (MPs) pollution. Specially, the main removal way of MPs from wastewater is to transfer MPs from liquid to solid phase, leading to its enrichment in waste activated sludge (WAS). Anaerobic digestion has been served as the most potential technique to achieve both resource recovery and sludge reduction, herein this review provides current information on occurrence, effect, and fate of MPs in anaerobic digestion of WAS.

Response of anaerobic digestion of waste activated sludge to residual ferric ions.

This study was conducted to investigate the effects of residual ferric ions (FI), released from iron or its oxides for wastewater or waste activated sludge (WAS) treatment, on anaerobic digestion of WAS. Herein it was found that the anaerobic digestion process was greatly affected by FI dosages as well as FI distributions. The responses of performance and microorganism suggested that a low FI (e.

[Denitrification Process and NO Production Characteristics of Heterotrophic Nitrifying Bacterium YL].

Because of the massive discharge of nitrogenous wastewater, the eutrophication of a water body is becoming increasingly serious, and how to effectively remove nitrogen from this wastewater remains an urgent problem to be solved. In this study, due to disadvantages in the traditional biological nitrogen removal process, such as complex and long procedures, high energy consumption, weak impact resistance, and NO release, the nitrogen removal theory by heterotrophic nitrification was further analyzed by discussing the physiological-biochemical, heterotrophic nitrification-aerobic denitrification, and NO production characteristics of a high-efficiency heterotrophic nitrifying bacteria YL. Results show that the strain YL had an eminent heterotrophic nitrification and aerobic denitrification ability, and NH-N, NO-N, and NO-N with concentration of 100 mg·L could be completely removed during the 24-hour incubation period.

[Simultaneous Nitrogen and Phosphorus Removal and Kinetics by the Heterotrophic Nitrifying Bacterium NP1].

Due to the problems of traditional biological nitrogen and phosphorus removal, including long process duration and high infrastructural and operational costs, the simultaneous nitrogen and phosphorus removal capabilities, influencing factors and kinetic characteristics were systematically studied using the heterotrophic nitrifier NP1 which possesses efficient simultaneous nitrogen and phosphorus removal ability. The results showed that strain NP1 exhibited efficient heterotrophic nitrification ability with a maximum ammonia removal rate of 99.12%.