Publications by authors named "Zhi-Wu Wang"

Article Synopsis
  • A study compared two pilot-scale MBBR treatment trains in a wastewater plant using methanol and glycerol as carbon sources over 371 days.
  • Both trains successfully met the total inorganic nitrogen requirement of < 3 mg/L while achieving significant savings in methanol (31.6% to 46.3%) and glycerol (30.9% to 43.8%).
  • The research revealed differing mechanisms for nitrite production; methanol favored anammox through competition with denitrification, while glycerol relied on the rates of denitratation and denitritation, highlighting the importance of the half-saturation constants of the carbon sources.
View Article and Find Full Text PDF

Food wastedigestatewas fed into a sequencing batch reactor (SBR) forHaloferax mediterranei(HM) to produce poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV). This SBR was operated uninterruptedly for 450 days to test its stability, during which the cycle time and volume exchange ratiowere varied to understand their impacts on the PHBV fermentation performance under ranged organic loading rates (OLR). Results showed that 1) PHBV productivity was proportional to OLR of food wastedigestate; 2) substrate and product inhibitions were two limiting factors constraining substrate utilization and PHBV yields; 3) PHBV titer was dependent on the hydraulic retention time of the SBR while a volume exchange ratio lower than 0.

View Article and Find Full Text PDF

Volatile fatty acids (VFAs) derived from arrested anaerobic digestion (AD) can be recovered as a valuable commodity for value-added synthesis. However, separating VFAs from digestate with complex constituents and a high-water content is an energy-prohibitive process. This study developed an innovative technology to overcome this barrier by integrating deep eutectic solvents (DESs) with an omniphobic membrane into a membrane contactor for efficient extraction of anhydrous VFAs with low energy consumption.

View Article and Find Full Text PDF
Article Synopsis
  • The study addresses the challenge of mineralizing organic phosphorus during anaerobic digestion of poultry wastewater (ADPW) to improve nutrient recovery strategies.
  • It focuses on the effect of organic acids, particularly oxalic acid, which successfully solubilized phosphorus at pH 2.5, achieving nearly 100% extraction efficiency.
  • Results showed that adding struvite seeds enhanced phosphorus and ammonia removal efficiencies, while the recovered product was a multi-nutrient fertilizer with high purity and minimal heavy metals.
View Article and Find Full Text PDF

Aerobic granulation is an emerging process in wastewater treatment that has the potential to accelerate sedimentation of the microbial biomass during secondary treatment. Aerobic granulation has been difficult to achieve in the continuous flow reactors (CFRs) used in modern wastewater treatment plants. Recent research has demonstrated that the alternation of nutrient-abundant (feast) and nutrient-limiting (famine) conditions is able to promote aerobic granulation in a CFR.

View Article and Find Full Text PDF

This study removes two technical constraints for transitioning full-scale activated sludge infrastructure to continuous flow, aerobic granular sludge (AGS) facilities. The first of these is the loss of treatment capacity as a result of the rapid washout of flocculent sludge inventory and in turn the potential loss of nitrification during initial AGS reactor startup. The second is the physical selector design which currently is limited to either the complex sequencing batch reactor selection or sidestream hydrocyclones.

View Article and Find Full Text PDF
Article Synopsis
  • Anaerobic digestion processes municipal sludge by reducing total solids and producing biogas, with hydrolysis being a key limiting step in this process.
  • The study found that thermal hydrolysis pretreatment (THP) can enhance sludge hydrolysis, with thermophilic anaerobic digestion (TAD) providing better solids reduction compared to mesophilic anaerobic digestion (MAD), although MAD yields more methane.
  • To optimize results, it's suggested to adjust solids retention time to mitigate intermediate product buildup that can inhibit methane production, and further research on ammonia removal techniques could improve efficiency.
View Article and Find Full Text PDF

Bacteria are key denitrifiers in the reduction of nitrate (NO -N), which is a contaminant in wastewater treatment plants (WWTPs). They can also produce carbon dioxide (CO) and nitrous oxide (NO). In this study, the autotrophic hydrogen-oxidizing bacterium sp TH20 was isolated for sustainable treatment of NO -N in wastewater.

View Article and Find Full Text PDF

Urban agriculture provides a promising, comprehensive solution to water, energy, and food scarcity challenges resulting from the population growth, urbanization, and the accelerating effects of anthropogenic climate change. Their close access to consumers, profitable business models, and important roles in educational, social, and physical entertainment benefit both developing and developed nations. In this sense, Urban Water Resource Reclamation Facilities (WRRFs) can play a pivotal role in the sustainable implementation of urban agriculture.

View Article and Find Full Text PDF

Although aluminum- and iron-based chemicals have been broadly used as the two most common types of coagulants for wastewater treatment, their impacts on the performance of downstream sludge management can be quite different and have not been well understood. This work reviewed and analyzed their similarities and differences in the context of the anaerobic digestion performance, dewaterability of digested sludge, and odor emission from dewatered biosolids. In short, iron-based coagulants tend to show less negative impact than aluminum-based coagulants.

View Article and Find Full Text PDF

The development of various therapeutic interventions, particularly immune checkpoint inhibitor therapy, have effectively induced tumor remission for patients with advanced lung cancer. However, few cancer patients can obtain significant and long-lasting therapeutic effects for the limitation of immunological nonresponse and resistance. For this case, it's urgent to identify new biomarkers and develop therapeutic targets for future immunotherapy.

View Article and Find Full Text PDF

Abnormally high-odor detection threshold (DT) values were detected for biosolids produced at one of the water resource recovery facilities (WRRFs) of Washington Suburban Sanitary Commission. As an inexpensive countermeasure, aeration of thickened sludge holding tanks (SHTs) was tested as a solution for mitigating the subsequent biosolids odor emission. Experimental results indicated that the extremely low-oxidation reduction potential (ORP) in the SHTs and the fermentation of high-rate-activated sludge were primarily contributors to the odor emission from the dewatered cake.

View Article and Find Full Text PDF

For immobilization and signal amplification of the probes, it is feasible and promising by using porous nanomaterials as nanocarriers. Herein, a novel label-free electrochemical immmunosensor was efficiently designed for ultrasensitive detection of procalcitonin (PCT). The immunosensor was prepared by using porous silica-coated gold nanorods (Au NRs@m-SiO) to load electroactive dye thionine (Thi) on the electrode surface.

View Article and Find Full Text PDF

RNA-binding proteins (RBPs) have been reported to be associated with the occurrence and progression of multiple cancers, but the role in gastric adenocarcinoma remains poorly understood. The present study aims to uncover potential RBPs associated with the survival of gastric adenocarcinoma, as well as corresponding biologic properties and signaling pathways of these RBPs. RNA sequencing and clinical data of GC were obtained from The Cancer Genome Atlas (n=373) and the Gene Expression Omnibus (GSE84437, n=433) database.

View Article and Find Full Text PDF

Plug flow reactors (PFRs) approximated by the connection of multiple completely stirred tank reactors (CSTRs) in series were used to achieve continuous flow aerobic granulation in real domestic wastewater. This study revealed, possibly for the first time, that the morphology and characteristics of aerobic granular sludge transformed in the course of a mixed liquor flow through a PFR. The feast zone, located at the front end of the PFR, can quickly develop filamentous structure on the surface of aerobic granular sludge which later disappeared in the famine zone at the back end of the PFR.

View Article and Find Full Text PDF

Plug flow reactors (PFRs) made of multiple completely stirred tank reactors (CSTRs) in series were used to cultivate aerobic granules in real domestic wastewater. Theoretically, changing the number of CSTR chambers in series will change the nature of plug flow, and thus alter the pattern of the feast/famine condition and impact the aerobic granulation progress. Therefore, PFRs were operated in 4-, 6-, and 8-chamber mode under the same gravity selection pressure (a critical settling velocity of 9.

View Article and Find Full Text PDF

Free ammonia (FA) inhibition has been taken advantage as a strategy to suppress the growth of nitrite-oxidizing bacteria (NOB) in aerobic granules stabilized in a continuous upflow airlift reactor to achieve partial nitritation. However, after nearly 18 months of continuous exposure of aerobic granules to FA in the reactor, the FA inhibition of NOB was proven ineffective, and the partial nitritation gradually shifted to partial nitrification even though the long-term granule structural stability remained excellent under the continuous-flow mode. The extent of NOB resistance to FA inhibition was quantified based on the kinetic response of NOB to various FA concentrations in the form of an uncompetitive inhibition coefficient.

View Article and Find Full Text PDF

Thermal hydrolysis pretreatment (THP) has been considered as an advanced approach to enhance the performance of anaerobic digestion treating municipal sludge. However, several drawbacks were also identified with THP including the formation of brown and ultraviolet-quenching compounds that contain recalcitrant dissolved organic nitrogen (rDON). Melanoidins produced from the Maillard reaction between reducing sugar and amino group have been regarded as a representative of such compounds.

View Article and Find Full Text PDF

Objective: The evaluation of GI-pill gastrointestinal electronic capsule for colonic transit test in patients with slow transit constipation (STC) was studied.

Materials And Methods: STC patients (n = 162) were randomly divided into experimental group (n = 84, orally taken GI-pill gastrointestinal electronic capsule and X-ray granule capsule) and control group (n = 78, orally taken X-ray granule capsule). Comparison of the time in colonic transit test between the two groups was conducted.

View Article and Find Full Text PDF

In this study, a modeling framework was developed to simulate biologically active filtration (BAF) headloss buildup in response to organic removal and nitrification. This model considered not only the biofilm growth on the BAF media but also the particle deposition in the BAF bed. In addition, the model also took temperature effect into consideration.

View Article and Find Full Text PDF

A partial nitritation continuous flow reactor (CFR) was operated for eight months demonstrating that partial nitritation granular sludge can remain stable under continuous flow conditions. The ammonia oxidizing bacteria (AOB)-to-nitrite oxidizing bacteria (NOB) activity ratios were determined for a series of granule sizes to understand the impact of mass diffusion limitation on the free ammonia (FA) inhibition of NOB. When dissolved oxygen (DO) limitation is the only mechanism for NOB suppression, the AOB:NOB ratio was usually found to increase with the granule size.

View Article and Find Full Text PDF

Constructed wetlands are multi-functional systems that can effectively store and transform pollutants primarily through natural processes. However, the removal of nitrogen pollutant by wetlands is highly variable, likely due to a combination of factors such as plant species-specific assimilation behavior, the effects of soil microbial diversity, and variable nitrogen inputs. In this study, the effects of plant species richness (i.

View Article and Find Full Text PDF

This pilot study was designed to explore the feasibility of achieving successful aerobic granulation in continuous flow infrastructure like that existing in modern wastewater treatment plants (WWTPs). Results demonstrated that aerobic granulation of activated sludge can be achieved in plug-flow reactors (PFRs) fed with primary effluent from a domestic WWTP with seasonal temperature variation between 10 and 22.5 °C.

View Article and Find Full Text PDF

High concentration of orthophosphate ion (OP) in anaerobically digested sludge can lead to struvite crystallization, deterioration of sludge dewaterability, and elevated mainstream OP loading through centrate recirculation. The Upper Occoquan Service Authority (UOSA) has observed seasonally high OP levels in its dewatering blend tank, which was found in this study to be a consequence of unwanted biological phosphorus accumulation during the intensified winter denitrification operation and the subsequent OP release in the course of anaerobic digestion. In order to control the nuisance struvite scaling issues, a bench study was conducted and cerium chloride (CeCl ) was dosed as an effective OP precipitant.

View Article and Find Full Text PDF

Cerium chloride (CeCl ), being a superior orthophosphate (OP) precipitant, was found to be able to significantly improve sludge dewaterability in terms of sludge cake dryness and capillary suction time. In order to offer insights into the mechanism behind OP removal associated dewaterability improvement, the change in sludge specific resistance to filtration (SRF), compressibility (K), and bound water contents (U ) in response to CeCl and CePO addition at the two cationic polymer doses was mathematically simulated. Results showed that 29.

View Article and Find Full Text PDF