Hongli Huang

Effects of physico-chemical parameters on the bacterial and fungal communities during agricultural waste composting.

The goal of this study was to identify and prioritize some of the physico-chemical parameters that contributed to bacterial and fungal community compositions during agricultural waste composting. Relationships between those parameters and microbial community compositions determined by PCR-DGGE were simultaneously evaluated by redundancy analysis (RDA). The results showed that the temporal variation of bacterial community composition was significantly related to water soluble carbon (WSC), ammonium and nitrate (P<0.05), while the most variation in distribution of fungal community composition was statistically explained by pile temperature, WSC, and moisture content (P<0.05). Significant amounts of the variation (54.9% and 56.0% for bacterial and fungal species data, respectively) were explained by those parameters, suggesting that those parameters were the most likely ones to influence, or be influenced by the bacterial and fungal species. Variation partitioning analyses indicated that WSC and pile temperature showed predominant effect on the bacterial and fungal community composition, respectively.

Carbon disulfide-modified magnetic ion-imprinted chitosan-Fe(III): A novel adsorbent for simultaneous removal of tetracycline and cadmium

A novel composite of carbon disulfide-modified magnetic ion-imprinted chitosan-Fe(III), i.e., MMIC-Fe(III) composite, was prepared as an efficient adsorbent for the simultaneous removal of tetracycline (TC) and Cd(II). This adsorbent showed excellent performance in removing TC and Cd(II) due to its rapid kinetics, high adsorption capacity, good reusability, and was well suited for use with real water samples. Kinetics studies demonstrated that the adsorption proceeded according to a pseudo-second order model. The adsorption isotherms were well described by the Langmuir model, with maximum adsorption capacity for TC and Cd(II) being 516.29 and 194.31mg/g, respectively. The synergistic effect of TC and Cd(II) adsorption might be due to the formation of TC-Cd(II) complex bridging the adsorbate and adsorbent. These properties demonstrate the potential application of MMIC-Fe(III) for the simultaneous removal of TC and Cd(II), and may provide some information for the synergistic removal of antibiotics and heavy metals from aquatic environments.

The application of iron-based technologies in uranium remediation: A review.

Remediating uranium contamination is of worldwide interest because of the increasing release of uranium from mining and processing, nuclear power leaks, depleted uranium components in weapons production and disposal, and phosphate fertilizer in agriculture activities. Iron-based technologies are attractive because they are highly efficient, inexpensive, and readily available. This paper provides an overview of the current literature that addresses the application of iron-based technologies in the remediation of sites with elevated uranium levels. The application of iron-based materials, the current remediation technologies and mechanisms, and the effectiveness and environmental safety considerations of these approaches were discussed. Because uranium can be reduced and reoxidized in the environment, the review also proposes strategies for long-term in situ remediation of uranium. Unfortunately, iron-based materials (nanoscale zerovalent iron and iron oxides) can be toxic to microorganisms. As such, further studies exploring the links among the fates, ecological impacts, and other environmentally relevant factors are needed to better understand the constraints on using iron-based technologies for remediation.

Ammonia-oxidizing bacterial communities and shaping factors with different Phanerochaete chrysosporium inoculation regimes during agricultural waste composting

This research was conducted to determine the effects of Phanerochaete chrysosporium inoculation on the ammonia-oxidizing bacterial (AOB) communities during agricultural waste composting. AOB communities with different inoculation regimes were investigated by quantitative PCR and denaturing gradient gel electrophoresis. Results showed that P. chrysosporium inoculation imposed certain stimulatory effects on the AOB amoA gene abundance. Samples with different inoculation regimes were dominated by different AOB species. Linear regression analysis indicated that the AOB community abundance had a significant positive correlation with pile pH (P < 0.05). The AOB amoA gene structure was best related to water soluble carbon (WSC) (P = 0.002, F = 14.17) and pile temperature (P = 0.04, F = 2.72). Variance partition analysis suggested that the sample property heterogeneity induced by inoculation imposed a greater impact (42.9%, P = 0.006) on the bacterial amoA gene structure than different inoculation regimes (23.6%, P = 0.022).

Selenium contamination, consequences and remediation techniques in water and soils: A review

&NA; Selenium (Se) contamination in surface and ground water in numerous river basins has become a critical problem worldwide in recent years. The exposure to Se, either direct consumption of Se or indirectly may be fatal to the human health because of its toxicity. The review begins with an introduction of Se chemistry, distribution and health threats, which are essential to the remediation techniques. Then, the review provides the recent and common removal techniques for Se, including reduction techniques, phytoremediation, bioremediation, coagulation‐flocculation, electrocoagulation (EC), electrochemical methods, adsorption, coprecipitation, electrokinetics, membrance technology, and chemical precipitation. Removal techniques concentrate on the advantages, drawbacks and the recent achievements of each technique. The review also takes an overall consideration of experimental conditions, comparison criteria and economic aspects. HighlightsSe contamination in environment emerged as a serious threat.Se causes various several fatal diseases in human beings and animals.Various treatment techniques for Se removal from water and soil are reviewed.Adsorption and membrane separation are seemed to be suitable on a commercial scale.The knowledge gaps to be addressed are proposed.

Effects of red mud based passivator on the transformation of Cd fraction in acidic Cd-polluted paddy soil and Cd absorption in rice

Highly effective, economical, and replicable ways of Cd-polluted paddy field remediation (in situ) are urgently needed. In this work, a yearlong field experiment (both early and late rice) was conducted to investigate the effects of red mud based passivator [red mud, diatomite, and lime (5:3:2)] on remediation of an acidic Cd-polluted paddy field in Hunan Province. Compared with the control, the addition of red mud based passivator in the early and late rice reduced Cd concentration in each part of the rice plant (with the most significant decrease rate of 59.18% and 72.11% for brown rice in the early rice and late rice seasons respectively). The effect of Cd reduction in the rice plant was persistent in the next growing season. The addition of red mud based passivator also reduced the exchangeable fraction of Cd in the soil and converted the exchangeable fraction into other unavailable fractions. This study demonstrated that the pH in acidic soil increased after the application of red mud based passivator. Furthermore, red mud based passivator had no effect on the concentrations of Olsen-K, Alkaline-N, Olsen-P in the soil, but increased rice grain yield. Overall, the results of this study indicated that the red mud based passivator at 0.6 kg m-2 could be a recommendation for Cd-polluted acidic paddy soil stabilization, and it would be a suitable method for remediation of Cd-polluted acidic paddy soil.

Biochar-based functional materials in the purification of agricultural wastewater: Fabrication, application and future research needs

Nowadays, agricultural contamination is becoming more and more serious due to the rapid growth of agricultural industry, which discharged antibiotics, pesticides or toxic metals into farmlands. A large number of researchers have applied biochar-based functional materials to the treatment of agricultural wastewater contamination. Meanwhile, biochar has also proved to be a very promising and effective technology in water purification field due to its various beneficial properties (e.g., cost effective, high specific surface area, and surface reactive groups). The focus of this review is to highlight the fabrication methods and application of biochar-based functional materials with the removal of different agricultural contaminants, and discuss the underlying mechanisms. However, the application of biochar-based functional materials is currently under its infancy, with the main hindrance is identified as the gap between laboratory scale and field application, immaturity of engineered biochar production technologies, and lack of quality standards. In order to fill these knowledge gaps, more efforts should be made to pay for the relevant research in future studies.

Population characteristics and influential factors of nitrogen cycling functional genes in heavy metal contaminated soil remediated by biochar and compost

Sixteen treatments of soil contaminated by Cu, Pb, and Zn by the addition of a different percentage of biochar and compost were incubated for 120 days. The abundance of denitrifying genes such as narG, nirK, nirS and nosZ and the ammonia-oxidizing amoA genes of ammonia-oxidizing archaea/bacteria (AOA/AOB), soil nitrite reductase activity (S-NiR) and their shaping factors were also determined. The relationships between functional genes, S-NiR, and physico-chemical parameters were analyzed using the Pearson correlation method. The study found that the changes in physico-chemical parameters, including water-soluble organic carbon (WSC), nitrate (NO3-) and ammonium (NH4+), were predominant in different treatments. The abundance of nirK and narG genes is most sensitive to the changes in the properties of the soil sample. Bacterial 16S rDNA gene abundance was significantly affected by NO3- and S-NiR (P < 0.05). Nitrifying genes were mainly correlated to WSC and S-NiR, while denitrifying genes were associated with pH, electrical conductivity, NO3- and S-NiR. The systematic study for the relationship between the genes and the environmental parameters will help us to deep understand the biological mechanisms of nitrogen cycle in heavy metal contaminated soils remediated by biochar and compost.

Chiral pharmaceuticals: Environment sources, potential human health impacts, remediation technologies and future perspective

Chiral pharmaceuticals (CPs), including non-steroid anti-inflammatory drugs (NSAIDs), β-blockers and some herbicide and pesticides, are widely used in aquaculture, clinical treatment and many other fields. However, people are increasingly concerned about such ubiquitous pollutants, which can frequently be detected in contaminated soil and water. In large part, the significant sources of chiral pharmaceuticals stem from industrial processes, such as the direct discharge of untreated or incompletely treated wastewaters containing chiral pharmaceuticals, incorrect storage and use, animal wastes and biosolids. The main ways for human exposure to chiral pharmaceuticals are the disease treatment process and chiral pharmaceuticals contaminants. According to the results of a series of toxic studies, some diseases, even cancers, may be associated with exposure to certain chiral pharmaceuticals. Therefore, the treatment of chiral pharmaceuticals has become an important issue. The current advanced remediation techniques for chiral pharmaceuticals include the conventional method (sorption and sonolysis), biotransformation (an aerobic granular sludge-sequencing batch reactor and constructed wetland system) and advanced oxidation processes (ozonation and photocatalysis). Herein, in this review, we summarize the current status and sources of chiral pharmaceuticals, potential effects on human health, as well as the superiority, disadvantages and prospects of current advanced remediation technologies. Moreover, we also anticipate the prospect of the future research needed for chiral pharmaceuticals pollutant remediation.

Key environmental factors to variation of ammonia-oxidizing archaea community and potential ammonia oxidation rate during agricultural waste composting

In this research, the abundance and structure of AOA amoA gene during agricultural waste composting were determined by quantitative PCR and sequencing techniques, respectively. Pairwise correlations between potential ammonia oxidation (PAO) rate, physicochemical parameters and the AOA abundance were evaluated using Pearson correlation coefficient. Relationships between these parameters, PAO rates and AOA community structure were evaluated by redundancy analysis. Results showed that 22 AOA gene OTUs were divided into the soil/sediment lineage by phylogenetic analyses. Significant positive correlations were obtained between AOA amoA gene abundance and moisture, ammonium, water soluble carbon (WSC) and organic matter (OM), respectively. Redundancy analysis showed OM, pH and nitrate significantly explained the AOA amoA gene structure. Pearson correlation revealed the PAO rate correlated positively to ammonium, AOA amoA gene abundance. These results indicated that AOA communities sense the fluctuations in surrounding environment, and ultimately react and influence the nitrogen transformation during agricultural waste composting.