Water eutrophication poses great threats to protection of water environment. Microbial remediation of water eutrophication has shown high efficiency, low consumption and no secondary pollution, thus becoming an important approach for ecological remediation. In recent years, researches on denitrifying phosphate accumulating organisms and their application in wastewater treatment processes have received increasing attention. Different from the traditional nitrogen and phosphorus removal process conducted by denitrifying bacteria and phosphate accumulating organisms, the denitrifying phosphate accumulating organisms can simultaneously remove nitrogen and phosphorus under alternated anaerobic and anoxic/aerobic conditions. It is worth noting that microorganisms capable of simultaneously removing nitrogen and phosphorus absolutely under aerobic conditions have been reported in recent years, but the mechanisms remain unclear. This review summarizes the species and characteristics of denitrifying phosphate accumulating organisms and the microorganisms capable of performing simultaneous nitrification-denitrification and phosphorous removal. Moreover, this review analyzes the relationship between nitrogen removal and phosphorus removal and the underlying mechanisms, discusses the challenges of denitrifying phosphorus removal, and prospects future research directions, with the aim to facilitate process improvement of denitrifying phosphate accumulating organisms.
Phosphorus ; Phosphates ; Wastewater ; Denitrification ; Waste Disposal, Fluid ; Nitrogen ; Bioreactors/microbiology* ; Nitrification ; Sewage

The wide use of ZnO and CuO nanoparticles in research, medicine, industry, and other fields has raised concerns about their biosafety. It is therefore unavoidable to be discharged into the sewage treatment system. Due to the unique physical and chemical properties of ZnO NPs and CuO NPs, it may be toxic to the members of the microbial community and their growth and metabolism, which in turn affects the stable operation of sewage nitrogen removal. This study summarizes the toxicity mechanism of two typical metal oxide nanoparticles (ZnO NPs and CuO NPs) to nitrogen removal microorganisms in sewage treatment systems. Furthermore, the factors affecting the cytotoxicity of metal oxide nanoparticles (MONPs) are summarized. This review aims to provide a theoretical basis and support for the future mitigating and emergent treatment of the adverse effects of nanoparticles on sewage treatment systems.
Wastewater/toxicity* ; Sewage/chemistry* ; Zinc Oxide/chemistry* ; Waste Disposal, Fluid ; Nanoparticles/chemistry* ; Metal Nanoparticles/chemistry* ; Nitrogen/metabolism* ; Water Purification

Objective: To analyze the level of PCDD/Fs exposure of occupational workers in the waste incineration industry and explore the risk of occupational exposure. Methods: In September 2021, literature on environmental PCDD/Fs exposure in waste incineration plants published from the establishment of the database to February 10, 2021 was retrieved from CNKI database. A total of 1365 literatures were retrieved, and 7 met the criteria for inclusion. The US Environmental Protection Agency (EPA) inhalation risk model was used to assess and analyze carcinogenic and non-carcinogenic risks of PCDD/Fs exposure among occupational workers in the waste incineration industry. Results: A total of 86 sampling sites were included in incineration plants in 7 regions. The study of Wuhan area showed that the concentration of working environment near the waste incinerator in the same factory was the highest, followed by the rest and office area in the factory. The concentration of PCDD/Fs in waste incinerators was the highest in Southwest China (4880.00-24880.00 pg TEQ/m(3)), and the lowest in Shenzhen (0.02-0.44 pg TEQ/m(3)). According to the cancer risk assessment, with the increase of exposure years, the risk of cancer increased. The highest risk of cancer was found in the waste incineration plants in Southwest China. When the exposure period was 1 year, the risk was moderate (22.40×10(-6)-114.20×10(-6)). When the exposure time was more than 5 years, the risk of cancer was high. In Jinan, workers working near the incinerator had a moderate risk of cancer after five years of exposure. In Zhejiang, workers were at medium risk of cancer after exposure for more than 20 years. Workers in Wuhan, Shanghai, Zhejiang Province, Shenzhen and the Pearl River Delta were still at low risk of cancer after 40 years of occupational exposure. HQ>1 of workers working near the waste incinerators in Jinan, Zhejiang Province and Southwest China, and the qualitative evaluation results showed that the non-carcinogenic risk was unacceptable. Conclusion: There are great differences in PCDD/Fs of occupational exposure in waste incineration industry, and the occupational exposure exceeding the occupational exposure limit has higher carcinogenic and non carcinogenic risks.
Humans ; Dibenzofurans ; Polychlorinated Dibenzodioxins/analysis* ; Air Pollutants/analysis* ; Incineration ; Dibenzofurans, Polychlorinated/analysis* ; China/epidemiology* ; Benzofurans ; Occupational Exposure/analysis* ; Carcinogens ; Risk Assessment ; Neoplasms ; Environmental Monitoring/methods*

Anaerobic granular sludge (AnGS), a self-immobilized aggregate containing various functional microorganisms, is considered as a promising green process for wastewater treatment. AnGS has the advantages of high volume loading rate, simple process and low excess sludge generation, thus shows great technological and economical potentials. This review systematically summarizes the recent advances of the microbial community structure and function of anaerobic granular sludge, and discusses the factors affecting the formation and stability of anaerobic granular sludge from the perspective of microbiology. Moreover, future research directions of AnGS are prospected. This review is expected to facilitate the research and engineering application of AnGS.
Sewage/chemistry* ; Waste Disposal, Fluid ; Anaerobiosis ; Microbiota ; Water Purification ; Bioreactors/microbiology*

Food wastes are rich in nutrients and can be used for producing useful chemicals through biotransformation. Some oleaginous microorganisms can use food wastes to produce lipids and high value-added metabolites such as polyunsaturated fatty acids, squalene, and carotenoids. This not only reduces the production cost, but also improves the economic value of the products, thus has large potential for commercial production. This review summarized the advances in food waste treatment, with a focus on the lipid production by oleaginous microorganisms using food wastes. Moreover, challenges and future directions were prospected with the aim to provide a useful reference for related researchers.
Biofuels ; Biotransformation ; Food ; Lipids ; Refuse Disposal

Landfill is one of the important sources of carbon tetrachloride (CT) pollution, and it is important to understand the degradation mechanism of CT in landfill cover for better control. In this study, a simulated landfill cover system was set up, and the biotransformation mechanism of CT and the associated micro-ecology were investigated. The results showed that three stable functional zones along the depth, i.e., aerobic zone (0-15 cm), anoxic zone (15-45 cm) and anaerobic zone (> 45 cm), were generated because of long-term biological oxidation in landfill cover. There were significant differences in redox condition and microbial community structure in each zone, which provided microbial resources and favorable conditions for CT degradation. The results of biodegradation indicated that dechlorination of CT produced chloroform (CF), dichloromethane (DCM) and Cl^- in anaerobic and anoxic zones. The highest concentration of dechlorination products occurred at 30 cm, which were degraded rapidly in aerobic zone. In addition, CT degradation rate was 13.2-103.6 μg/(m²·d), which decreased with the increase of landfill gas flux. The analysis of diversity sequencing revealed that Mesorhizobium, Thiobacillus and Intrasporangium were potential CT-degraders in aerobic, anaerobic and anoxic zone, respectively. Moreover, six species of dechlorination bacteria and eighteen species of methanotrophs were also responsible for anaerobic transformation of CT and aerobic degradation of CF and DCM, respectively. Interestingly, anaerobic dechlorination and aerobic transformation occurred simultaneously in the anoxic zone in landfill cover. Furthermore, analysis of degradation mechanism suggested that generation of stable anaerobic-anoxic-aerobic zone by regulation was very important for the harmless removal of full halogenated hydrocarbon in vadose zone, and the increase of anoxic zone scale enhanced their removal. These results provide theoretical guidance for the removal of chlorinated pollutants in landfills.
Bacteria/metabolism* ; Biodegradation, Environmental ; Carbon Tetrachloride/metabolism* ; Methane/metabolism* ; Waste Disposal Facilities

Objective: To analyze the situation and influencing factors of school meals leftover among primary and secondary school students in the area of the Nutrition Improvement Program for Rural Compulsory Education Students, improve the quality of school meals, develop healthy dietary behavior, and reduce food waste. Methods: In 2019, among the 50 monitoring counties that implemented the Compulsory Education Student Nutrition Improvement Program, two primary schools and two junior schools were randomly selected according to different food supply patterns.This study randomly selected one or two classes from grade 3 to grade 9. Basic information and school meals of 26 778 students were collected by using a student questionnaire. Multivariate logistic regression was used to analyze the influencing factors of leftovers rate. Results: 54.93% (14 709) of students wasted school meals, in which the highest rate was the staple food, with the main reason as "not in favor". 11.87% (1 743) of the students wasted school meals 6-7 days a week, with 54.20% (7 957) of students wasted but in less amount. The leftover rate of staple food was the highest (29.78%), followed by vegetables and meat. The main reason of leftovers was that they didn't like this kind of food (33.52%). The rate of school meal waste was higher for girls (OR=1.19,95%CI:1.13-1.25), junior high school students (OR=1.17, 95%CI: 1.11-1.25), resident students (OR=1.06, 95%CI: 1.00-1.12), lower economic level (OR=1.06, 95%CI: 1.00-1.12), parents working outside their houses (OR=1.22, 95%CI: 1.13-1.30), health education classes (OR=1.70, 95%CI: 1.40-2.06), company-based meals (OR=1.89, 95%CI: 1.71-2.07) and school meals were not as good as home food(OR=1.89, 95%CI: 1.78-2.00)(P<0.05). Conclusions: It is common for poor rural primary and middle school students in central and western China to waste school meals, and the reasons were affected by many factors. Reducing food waste requires the joint efforts of individuals, families, schools and society.
Female ; Food Services ; Humans ; Meals ; Refuse Disposal ; Schools ; Students

Aims: The primary aim of this study was to utilize abundant palm oil mill effluent (POME) waste and turn it into a value-added product of biomass fuel with high calorific energy value (CEV) via fermentation and drying process, then simultaneously reduce abundant liquid waste. Methodology and results: POME is available abundantly in Malaysia and only a small portion of it is utilized to produce other value-added products. In this study, fermentation of POME in the presence of bacteria (Lysinibacillus sp.) and fungus (Aspergillus flavus) separately at 37 °C, 180 rpm for 5 days, followed by overnight oven-drying at 85 °C was conducted. Four fermentation medium conditions were performed, viz.: (1) autoclaved POME, (2) autoclaved POME with the addition of Lysinibacillus sp., (3) autoclaved POME with the addition of A. flavus and (4) POME as it is (non-sterile). Conclusion, significance and impact of study Among all conditions, fermentation utilizing autoclaved POME in the presence of A. flavus evinced the highest CEV of 25.18 MJ/kg. The fermentation in the presence of Lysinibacillus sp. strain revealed high COD and BOD removal efficiency of 59.20% and 320.44 mg/L as well as the highest reduction of oils and grease among other groups with the value of 15.84%. Future research directions are proposed for the elucidation of co-fermentation in the presence of both Lysinibacillus sp. and A. flavus.
Palm Oil ; Biomass ; Biofuels ; Waste Disposal, Fluid

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China ; Cryptosporidiosis/microbiology* ; Cryptosporidium/isolation & purification* ; Giardia/isolation & purification* ; Giardiasis/microbiology* ; Humans ; Risk Assessment ; Water Microbiology ; Water Supply/statistics & numerical data*

INTRODUCTION: Unregulated biomedical waste management is an emerging public health problem in the Philippines. This study aimed to differentiate the knowledge, attitudes, and practices of nurses and medical technologists toward biomedical waste management. METHODS: Using an analytic cross-sectional study design, an online survey of nurses and medical technologists from hospitals around the Philippines was conducted. A 27-item questionnaire covering knowledge, attitudes and practices was used. The percentages of correct answers and mean scores in each domain was compared between the nurses and medical technologists. RESULTS: A total of 196 respondents consisting of 77 registered nurses and 119 medical technologists were included in the study. Medical technologists had significantly better knowledge scores than nurses on disposal procedures for expired blood units and by-products waste (55% vs. 19%, p = 0.026). Both had low correct responses on adequate disposal of human tissue remains, throwing blood waste into domestic waste, and throwing of expired medications in domestic waste. There was no significant difference in the attitude of nurses and medical technologists. Nurses had significantly better practice scores on disposal of liquid waste in bags (84.4% vs. 68.9, p = 0.018), but medical technologists fared better at disposal of human tissue together with other waste (13.0% vs. 2.5%, p = 0.006). CONCLUSION Both nurses and medical technologists had adequate knowledge of some aspects but were lacking in others. There was no significant difference in the attitude of nurses and medical technologists towards biomedical waste management. Half of the respondents practiced proper biomedical waste management.
Medical Laboratory Personnel ; Waste Management ; Knowledge ; Attitude