Bo Liu

Bio: Bo Liu is an academic researcher from Harbin Institute of Technology. The author has contributed to research in topic(s): Activated sludge & Wastewater. The author has an hindex of 4, co-authored 7 publication(s) receiving 309 citation(s).

Decontamination of Wastewaters Containing Synthetic Organic Dyes by Electrochemical Methods: A Review

Abstract: Bioelectrochemical systems or electrochemical reduction reactors have great potential for treating wastewater that contains dyes for decolorization. They are reported to enhance decolorization rate and degree with external energy supply and to help microorganisms or noble metal as catalysts. Till now literatures regarding dye decolorization with electron reduction using BESs or electrochemical reactors is deficient. This paper reviews the performance limitations, future prospects, and improvements of the common used dyes decolorization and decolorization with external voltage or current supply in Bioelectrochemical systems.

Optimization of operating parameters for sludge process reduction under alternating aerobic/oxygen-limited conditions by response surface methodology

Abstract: Batch tests were employed to estimate the optimal conditions for excess sludge reduction under an alternating aerobic/oxygen-limited environment using response surface methodology. Three key operating parameters, initial mixed liquor suspended solids (initial MLSS), HRT (hydraulic retention time) and reaction temperature (T), were selected, and their interrelationships studied by the Box–Behnken design. The experimental data and ANOVA analysis showed that the coefficient of determination ( R 2 ) was 0.9956 and the adj R 2 was 0.9912, which demonstrates that the modified model was significant. The optimum conditions were predicted to give a maximal ΔMLSS yield of 226 mg/L at an initial MLSS of 10,021 ± 50 mg/L, an HRT of 9.1 h and a reaction temperature of 29 °C. The prediction was tested by triplicate experiments, where a ΔMLSS yield of 233 mg/L was achieved under the chosen optimal conditions. This excellent correlation between the predicted and measured values provides confidence in the model.

Characterizing the fluorescent products of waste activated sludge in dissolved organic matter following ultrasound assisted ozone pretreatments

Abstract: This study investigated the effects of ozone and ultrasound (US) pretreatments, both individually and combined, on waste activated sludge reduction. Batch tests were conducted first to optimize the individual ozone and US pretreatments. Maximum sludge reduction ratios of 10.89% and 23% were obtained at 0.15 g O3/g total solids ozone dose and 1.5 W/mL US energy density, respectively. The combined ozone and US pretreatments were studied using response surface methodology. A maximum sludge reduction ratio of 40.14% was achieved by the combined ozone/US pretreatment with an ozone dose of 0.154 g O3/g total solids and an US energy density of 1.445 W/mL. The analysis of the dissolved organic matter by three-dimensional excitation–emission matrix fluorescence spectroscopy showed that the combined pretreatment was superior to the individual ozone and US pretreatments, and also demonstrated the synergetic effect of these two combined pretreatments.

Treatability study of 3,3',4',5-tetrachlorosalicylanilide (TCS) combined with 2,4,6-trichlorophenol (TCP) to reduce excess sludge production in a sequence batch reactor.

Abstract: The present study investigated the synergistic effects of a novel combined uncoupler of TCS and TCP on excess activated sludge reduction during a 60-day operation using a sequence batch reactor (SBR). Response surface methodology (RSM) was employed to obtain the optimal dosage of the combined uncoupler. The results of 60-day operation demonstrated the combined uncoupler had effectively reduced the sludge yield by approximately 52%, without serious affecting the substrate removal efficiency. The high sludge reduction rate revealed that it was feasible and effective to utilize a combined uncoupler to limit excess activated sludge. The three-dimensional excitation–emission matrix (EEM) fluorescence spectroscopy analysis of activated sludge with different metabolic uncouplers indicated that tryptophan, tyrosine protein-like substances and tryptophan, tyrosine amino-like substances were reduced by adding a combined uncoupler. Moreover, the variation of sludge components provided a better understanding of the effects of uncouplers on activated sludge reduction.

Treatment device capable of intensifying degrading of wastewater containing azo dyes by microbial electric auxiliary system and water treatment method

Abstract: The invention relates to a treatment device capable of intensifying degrading of wastewater containing azo dyes by a microbial electric auxiliary system and a water treatment method, belongs to the field of printing and dyeing wastewater treatment and mainly relates to wastewater treatment device and method. The invention aims to solve the technical problem that existing method of treating wastewater containing azo dyes is low in decolourization ratio of wastewater and poor in COD removing capacity. The device provided by the invention comprises a reactor anode collector plate, a reactor cathode collector plate, a reference electrode, a reactor water inlet, a mud discharge opening, a reactor perforated water distributing plate, a return pipe, a return pump, a lead, a water outlet, an anode filler layer clapboard, a cathode filler layer clapboard and a gas collecting opening. The water treatment method comprises the following steps that wastewater enters the treatment device capable of intensifying degrading of wastewater containing azo dyes by the microbial electric auxiliary system through the reactor water inlet; water is discharged from the water outlet to realize water treatment. The method provided by the invention is high in decolourization ratio of wastewater and high in COD removing capacity when used for treating wastewater containing azo dyes.

New perspectives for Advanced Oxidation Processes.

Abstract: Advanced Oxidation Processes (AOPs) are called to fill the gap between the treatability attained by conventional physico-chemical and biological treatments and the day-to-day more exigent limits fixed by environmental regulations. They are particularly important for the removal of anthropogenic pollutants and for this reason, they have been widely investigated in the last decades and even applied in the treatment of many industrial wastewater flows. However, despite the great development reached, AOPs cannot be considered mature yet and there are many new fields worthy of research. Some of them are going to be briefly introduced in this paper, including hybrid processes, heterogeneous semiconductor photocatalysis, sulphate-radical oxidation and electrochemical advanced oxidation for water/wastewater treatment. Moreover, the use of photoelectrochemical processes for energy production is discussed. The work ends with some perspectives that can be of interest for the ongoing and future research.

Complete removal of AHPS synthetic dye from water using new electro-fenton oxidation catalyzed by natural pyrite as heterogeneous catalyst.

Abstract: The mineralization of a new azo dye - the (4-amino-3-hydroxy-2-p-tolylazo-naphthalene-1-sulfonic acid) (AHPS) - has been studied by a novel electrochemical advanced oxidation process (EAOP), consisting in electro-Fenton (EF) oxidation, catalyzed by pyrite as the heterogeneous catalyst - the so-called 'pyrite-EF'. This solid pyrite used as heterogeneous catalyst instead of a soluble iron salt, is the catalyst the system needs for production of hydroxyl radicals. Experiments were performed in an undivided cell equipped with a BDD anode and a commercial carbon felt cathode to electrogenerate in situ H2O2 and regenerate ferrous ions as catalyst. The effects on operating parameters, such as applied current, pyrite concentration and initial dye content, were investigated. AHPS decay and mineralization efficiencies were monitored by HPLC analyses and TOC measurements, respectively. Experimental results showed that AHPS was quickly oxidized by hydroxyl radicals (OH) produced simultaneously both on BDD surface by water discharge and in solution bulk from electrochemically assisted Fenton's reaction with a pseudo-first-order reaction. AHPS solutions with 175 mg L(-1) (100 mg L(-1) initial TOC) content were then almost completely mineralized in 8h. Moreover, the results demonstrated that, under the same conditions, AHPS degradation by pyrite electro-Fenton process was more powerful than the conventional electro-Fenton process.

Minimization of excess sludge production by in-situ activated sludge treatment processes--a comprehensive review.

Abstract: The widespread application of conventional activated sludge treatment process has been employed to deal with a variety of municipal and industrial sewage. While the generation of waste activated sludge (WAS) was considerably huge, the management and disposal expenses were substantially costly. A promising process aimed for WAS reduction during the operation process is urgently needed. Thus, increasing attentions emphasizing on the improved or novel sludge reduction processes should be intensively recommended in the future. This review presents the current and emerging technologies for excess sludge minimization within the process of sewage treatment. The ultimate purpose of this paper is to guide or inspire researchers who are seeking feasible and promising technologies (or processes) to tackle the severe WAS problem.

High-efficiency removal of lead from wastewater by biochar derived from anaerobic digestion sludge.

Abstract: The properties of biochar derived from waste activated sludge and anaerobic digestion sludge under pyrolysis temperature varying from 400°C to 800°C were investigated. The heavy metals adsorption efficiency of the sludge-derived biochar was also examined. Among the biochar samples tested, ADSBC600 possessing highly porous structure, special surface chemical behaviors and high thermal stability was found to remove Pb2+ from aqueous solutions efficiently with an adsorption capacity of 51.20mg/g. The Pb2+ adsorption kinetics and isotherm for ADSBC600 can be described using the pseudo second-order model and Langmuir isotherm, respectively. Analysis of the characteristics of biochar before and after metal treatment suggests that electrostatic attraction, precipitation, surface complexation and ion exchange are the possible Pb2+ removal mechanisms. This study demonstrates a successful example of waste refinery by converting anaerobic digestion sludge to feasible heavy metal adsorbents to implement the concept of circular economy.

A Review: Microalgae and Their Applications in CO_2 Capture and Renewable Energy

Abstract: Fossil fuels, which are recognized as unsustainable sources of energy, are continuously consumed and decreased with increasing fuel demands. Microalgae have great potential as renewable fuel sources because they possess rapid growth rate and the ability to store high-quality lipids and carbohydrates inside their cells for biofuel production. Microalgae can be cultivated on opened or closed systems and require nutrients and CO_2 that may be supplied from wastewater and fossil fuel combustion. In addition, CO_2 capture via photosynthesis to directly fix carbon into microalgae has also attracted the attention of researchers. The conversion of CO_2 into chemical and fuel (energy) products without pollution via this approach is a promising way to not only reduce CO_2 emissions but also generate more economic value. The harvested microalgal biomass can be converted into biofuel products, such as biohydrogen, biodiesel, biomethanol, bioethanol, biobutanol and biohydrocarbons. Thus, microalgal cultivation can contribute to CO_2 fixation and can be a source of biofuels. This article reviews the literature on microalgae that were cultivated using captured CO_2, technologies related to the production of biofuels from microalgae and the possible commercialization of microalgae-based biofuels to demonstrate the potential of microalgae. In this respect, a number of relevant topics are addressed: the nature of microalgae (e.g., species and composition); CO_2 capture via microalgae; the techniques for microalgal cultivation, harvesting and pretreatment; and the techniques for lipid extraction and biofuel production. The strategies for biofuel commercialization are proposed as well.