Jianbing Li

Recent development in the treatment of oily sludge from petroleum industry: A review

Oily sludge is one of the most significant solid wastes generated in the petroleum industry. It is a complex emulsion of various petroleum hydrocarbons (PHCs), water, heavy metals, and solid particles. Due to its hazardous nature and increased generation quantities around the world, the effective treatment of oily sludge has attracted widespread attention. In this review, the origin, characteristics, and environmental impacts of oily sludge were introduced. Many methods have been investigated for dealing with PHCs in oily sludge either through oil recovery or sludge disposal, but little attention has been paid to handle its various heavy metals. These methods were discussed by dividing them into oil recovery and sludge disposal approaches. It was recognized that no single specific process can be considered as a panacea since each method is associated with different advantages and limitations. Future efforts should focus on the improvement of current technologies and the combination of oil recovery with sludge disposal in order to comply with both resource reuse recommendations and environmental regulations. The comprehensive examination of oily sludge treatment methods will help researchers and practitioners to have a good understanding of both recent developments and future research directions.

Microbial community succession and lignocellulose degradation during agricultural waste composting

The changes of microbial community during agricultural waste composting were successfully studied by quinone profiles. Mesophilic bacteria indicated by MK-7 and mesophilic fungi containing Q-9 as major quinone were predominant and seemed to be important during the initial stage of composting. Actinobacteria indicated by a series of partially saturated and long-chain menaquinones were preponderant during the thermophilic period. While Actinobacteria, fungi and some bacteria, especially those microbes containing MK-7(H4) found in Gram-positive bacteria with a low G+C content or Actinobacteria were found cooperate during the latter maturating period. Since lignocellulsoe is abundant in the agricultural wastes and its degradation is essential for the operation of composting, it’s important to establish the correlation between the quinone profiles changes and lignocellulose degradation. The microbes containing Q-9 or Q-10(H2) as major quinone were found to be the most important hemicellulose and cellulose degrading microorganisms during composting. While the microorganisms containing Q-9(H2) as major quinone and many thermophilic Actinobacteria were believed to be responsible for lignin degradation during agricultural waste composting.

Denitrification of simulated municipal wastewater treatment plant effluent using a three-dimensional biofilm-electrode reactor: Operating performance and bacterial community

A three-dimensional biofilm-electrode reactor (3D-BER) was applied for nitrate removal from simulated municipal wastewater treatment plant (WWTP) effluent. It was found that when the influent C/N ratio ranged from 1.0 to 2.0, both heterotrophic and autotrophic denitrifying microorganisms played important roles in nitrate removal. The extension of hydraulic retention time (HRT) could enhance nitrate removal, but too long HRT was not necessary. A phylogenetic tree of gene sequences in biofilm was established, and the biofilm was abundant with Thauera-like and Enterobacter-like bacteria. The results illustrated that 3D-BER is a feasible and effective technology for the denitrification of WWTP effluent with poor organic carbon source. A nitrate removal of 98.3% was obtained with C/N ratio of 3.0 and HRT of 7h. About 85.0-90.0% of nitrate removal was found at a C/N ratio of 1.5 and HRT of 10h due to cooperative heterotrophic and autotrophic denitrification.

Integrated Fuzzy-Stochastic Modeling of Petroleum Contamination in Subsurface

An integrated approach associated with fuzzy set theory, Monte Carlo simulation, and interval analysis are proposed in this study to address the uncertainties in simulating petroleum contamination in the subsurface. A numerical multiphase compositional modeling technique is implemented to examine the fate of petroleum contaminants in groundwater. The intrinsic permeability, longitudinal dispersivity, and soil porosity are considered as uncertain input parameters. A three-dimensional (3D) case of a petroleum contamination problem is presented to illustrate the suitability and capability of the proposed methods for managing uncertainties. The results show that the uncertainties in intrinsic permeability and porosity will have significant impacts on the modeling outputs. Neglecting these uncertainties may result in an unreasonable estimation of the contaminant fate in the subsurface.

Fuzzy chance-constrained linear fractional programming approach for optimal water allocation

A fuzzy chance-constrained linear fractional programming method was developed for agricultural water resources management under multiple uncertainties. This approach improved upon the previous programming methods, and could reflect the ratio objective function and multiple uncertainties expressed as probability distributions, fuzzy sets, and their combinations. The proposed approach is applied to an agricultural water resources management system where many crops are considered under different precipitation years. Through the scenarios analyses, the multiple alternatives are presented. The solutions show that it is applicable to practical problems to address the crop water allocation under the precipitation variation and sustainable development with ratio objective function of the benefit and the irrigation amount. It also provides bases for identifying desired agriculture water resources management plans with reasonable benefit and irrigation schedules under crops.

An inexact two-stage stochastic programming model for water resources management in Nansihu Lake Basin, China

In this study, an inexact two-stage water resources management model was developed for multi-regional water resources planning in the Nansihu lake Basin, China. Four planning districts, four water users, and five water sources were considered in the optimization model, with net system benefit, recourse cost, water supply cost, and wastewater treatment cost being analyzed. Methods of interval-parameter programming (IPP) and two-stage stochastic programming (TSP) were incorporated into the model to tackle uncertainties described by both interval values and probability distributions. A number of scenarios corresponding to different river inflow levels were examined, and the results indicated that different inflow levels could lead to different water allocation schemes with varied system benefit and system-failure risk. In general, the developed model can provide an effective linkage between economic benefits and the associated penalties attributed to the violation of predefined policies. The modeling results were valuable for supporting the adjustment or justification of the existing water allocation schemes within a complicated water resources system under uncertainty.

Effect of Triton X-100 on the removal of aqueous phenol by laccase analyzed with a combined approach of experiments and molecular docking

Effects of Triton X-100 on the removal of aqueous phenol catalyzed by laccase were studied. The optimal concentration of Triton X-100 was 155 μM to improve phenol removal when the concentrations of phenol and laccase were 50 mg/L and 0.05 mg/mL, respectively. Laccase activity was increased with Triton X-100 at concentrations from 31 to 930 μM and the highest increase was about 17% by 930 μM Triton X-100. The removal efficiencies of phenol with 155 μM Triton X-100 were 1.2, 1.6, 3.4, 4.5, and 5.7 fold those of the control after 6h when the initial concentrations of phenol were 50, 100, 200, 400 and 600 mg/L, respectively. Molecular docking method was used to analyze the interactions between laccase and substrates. Docking results showed that phenol formed hydrogen bonds and hydrophobic interactions with laccase, whereas Triton X-100 formed hydrophobic interactions with laccase, which may increase the laccase activity and enhance phenol removal. The reaction of phenol removal was also characterized using UV spectra. The results indicated that the presence of low concentrations of Triton X-100 for phenol removal catalyzed by enzymes may be an alternative to the present phenol removal processes in water treatment or remediation.

Influence of rhamnolipids and Triton X-100 on adsorption of phenol by Penicillium simplicissimum.

The effects of rhamnolipids and Triton X-100 on phenol adsorption by Penicillium simplicissimum were studied. The optimum pH was 7 for phenol adsorption by all the test biomasses. The adsorption of phenol at pH 7 by biomass pre-treated with 0.05% Triton X-100, 0.2% Triton X-100, 0.05% rhamnolipids and 0.005% rhamnolipids was 3.4, 2.7, 2.4, and 1.8-fold, respectively, that of untreated biomass. The pseudo-second-order model and the Freundlich isotherms described the adsorption processes better than the pseudo-first-order model and the Langmuir isotherms, respectively. The pre-treatments by surfactants increased the zeta potential and hydrophobicity of P. simplicissimum. Analysis of the cell surface by Fourier transform infrared spectrometry, energy dispersive X-ray, and environmental scanning electron microscopy indicated that the pre-treatments by surfactants changed the cell surface functional groups, element concentrations and micrographs. The results indicated that surfactants can be potentially used to increase phenol adsorption.

NRSRM: a decision support system and visualization software for the management of petroleum-contaminated sites

A robust decision-support system (DSS) was developed to provide environmental managers with an integrated measure for tackling subsurface contamination problems. Such a DSS included components of mathematical modeling, risk assessment, remediation-technique screening, and monitoring-program design. A visual-language-based software package, named NRSRM, was developed for facilitating a variety of functions within the DSS. It provided a collection of measures for analyzing and visualizing subsurface contamination problems. A contaminated site located in western Canada was examined to demonstrate its applicability. By exploring different remedial technologies, NRSRM recommended six alternatives for cleaning up the site. Users can click selected items under each alternative to acquire more information of the related actions and efficiencies.

GIS-based distributed model for simulating runoff and sediment load in the Malian River Basin

GIS-based modeling is an effective approach for reflecting spatially-varied complexities in watershed systems. In this study, a GIS-aided distributive hydrological model was developed to simulate runoff and sediment transport in a loess-plateau context with semi-arid climate, sparse vegetation, and serious soil erosion. The model was then applied to a case study in the Malian River Basin, which is one of the largest catchments in the middle reach of the Yellow River. Based on the GIS technique, the DEM of the study basin was successfully used to delineate the stream network and extract information of catchment characteristics. The results show satisfactory accuracy for runoff simulation. Especially, the integrated soil-erosion and hydrological models can be used for simulating both runoff and sediment loads, which provide a useful decision-support tool for water resources management and pollution control. This study is an attempt to develop a distributed rainfall-runoff model for river basins in the loess plateau region. The developed model can also be extended to larger basins. Further works of field survey and investigation would be helpful for better calibrating critical parameters and thus improving performance of the developed model.