Yangcheng Lake, a typical fishery lake in the middle and lower reaches of the Yangtze River, is threatened by eutrophication. As the main performers of biogeochemical cycles, microorganisms affect the ecological stability of the lake. To study the structural characteristics of the microbial community in Yangcheng Lake and rivers entering Yangcheng Lake and the response relationship with environmental factors, the microbial community was categorized based on the contour of Yangcheng Lake, the major rivers entering Yangcheng Lake, and the pollution sources. The distribution characteristics of seven physicochemical indices were analyzed, including total organic carbon (TOC), total nitrogen (TN), total phosphorus (TP), water temperature (WT), pH, dissolved oxygen (DO), and ratio of total nitrogen to total phosphorus (TN/TP). Characterization of microbial community structure based on 16S rRNA high-flux sequencing technology and ANOSIM analysis were used to explore the differences in the relative abundance of microorganisms at each sampling point in the lake and rivers, and redundancy analysis (RDA) was used to analyze the relationship between the microbial community and physicochemical factors. The results showed that the dominant phyla, genera of microorganisms, and the total number of OTUs in the lake and rivers were similar. The dominant phyla included Proteobacteria, Actinobacteria, Bacteroidetes, Cyanobacteria, and Verrucomicrobia; the dominant genera included the hgcI clade, CL500-29 marine group, Microcystis PCC-7914, Chloroplast_norank, Clade III_norank, and Flavobacterium . ANOSIM analyses revealed that the microbial community of Yangcheng Lake exhibited an association with geographical space, while the microbial community in the rivers that was linked to the type of pollution source. Redundancy analysis (RDA) indicated that dissolved oxygen (DO), total nitrogen (TN), and pH were significantly correlated with the dominant phyla in Yangcheng Lake ( p < 0.05), while total nitrogen (TN), water temperature(WT), and the ratio of total nitrogen to total phosphorus (TN/TP) were significantly related with the dominant genera in Yangcheng Lake ( p < 0.05). Total nitrogen (TN) was also significantly linked to the dominant phyla and genera of the tributaries ( p < 0.05). Despite the structural similarities in microbial communities between Yangcheng Lake and its inflowing rivers, environmental factors demonstrated significant associations with these communities, providing crucial data support for pollution prevention and the ecological restoration of Yangcheng Lake.
Taking an improved A~2/O process in northern China(with a design scale of 6×10~4 m~3·d -1 ) as an example, the relationship between carbon source storage and biological nitrogen and phosphorus removal was investigated based on the operation data of a whole year, and the utilization efficiency of carbon source and energy consumption was analyzed. The results showed that from July to September, the comprehensive utilization efficiency of carbon source reached 53%～55%, which proved that more than 50% consumed carbon source was used for biological nitrogen and phosphorus removal. Denitrifying bacteria were more sensitive to environmental changes than phosphorus accumulating bacteria. The extension cost of additional carbon source accounted for 20.5% of the direct cost. It was pointed out that the sewage treatment plant should fully consider the influence of the change of inlet and outlet water quality and environmental conditions on the effective utilization of carbon sources, so as to provide technical guidance and reference for the regulation and operation of municipal wastewater treatment plant with A~2/O process and other conventional processes.
In order to effectively deal with a large number of intermittent VOCs generated in the production process of the pharmaceutical industry, a direct catalytic combustion process of multi-effect heat recovery composed of heat storage, heat exchange, heat recovery and heat supplement was constructed. Combined with the fuzzy PID temperature control strategy, 500 g·m -3 platinum-palladium alloy plated on honeycomb ceramic carrier was used as a catalyst to treat intermittent organic waste gas discharged from a pharmaceutical industry.As a result, the feasibility of this technology in processing intermittent organic waste gas discharged from the pharmaceutical industry was verified. The results showed that under the condition that the mass concentration of VOCs emitted by the pharmaceutical industry fluctuated greatly from 22 mg·m -3 to 6 293 mg·m -3 , the multieffect heat recovery in catalytic combustion process could stably and effectively purify the organic waste gas emitted by the pharmaceutical industry, and the VOCs emitted after purification. The concentration was less than 20 mg·m -3 , and the comprehensive treatment efficiency was more than 97%. with the increase of VOCs mass concentration, the treatment efficiency was close to 100%. Using this technology, the average annual operating cost of this process was 357 200 yuan, which was reduced by more than 27% compared with the traditional process. In conclusion, the multi-effect heat recovery in catalytic combustion process could effectively treat intermittent VOCs in the pharmaceutical industry, and this study can provide a reference for the treatment of intermittent VOCs in the pharmaceutical industry, and also for other industries.
Sewage treatment to meet the demand of recycled water quality is increasing, and the technology suitable for the situation in our country has yet to be optimized as it gradually explores limit of technology（LOT） of sewage nutrition removal. This paper constructs an improved system readiness level（SRL） evaluation method based on the existing technology readiness level（TRL） and algorithm matrix, and relies on the LOT alternative technology combinations related to the national "Water Pollution Control and Treatment Science and Technology Major projects" during the “11th Five-Year Plan”, “12th Five-Year Plan” and “13th Five-Year Plan” and other domestic and foreign alternative technology combinations that meet the requirements of LOT.By comprehensive quantitative evaluation of TRL and improved SRL, the current situation of the development of LOT technologies in our country is sorted out and 12 candidate technologies combinations are selected.Among the 12 selected LOT alternative technology combinations, the SRL value of “A~2O+Deep-Bed Denite Filters Technology ”, “A~2O+MBBR+Coagulation Technology ” and “A~2O+Self-acctive Denitrification Technology+BAF” can reach 0.8～1, reaching the stage of production, operation and maintenance, which can be directly applied in production and generate high application benefits in the market. While the cost of TN and TP per unit mass removal of the three technology combinations is high, and the core functional processes are mainly traditional reactor technologies. Most of the single technology TRL levels are above 7, and most of the improved SRL values are between 0.6 and 0.8, which are in the stage of system development and verification. The relevant technology combinations are improving product stability for real market promotion. And most alternative technology combinations make the great use of the properties of ecological technologies such as plants and wetlands, which not only realizes strong synchronous nitrogen and phosphorus removal, but also has the market advantage of low operation and maintenance cost, which has the potential to be popularized.. The LOT alternative technology combinations basically realize the cost optimization and low carbon and low consumption technology operation mode, and meets the needs of waste water reclamation and the improvement of ecological environment.
A novel configuration of micro-aerobic/aerobic reactor at a pilot scale of 3 000 m~3·d -1 （series Ⅰ and Ⅱ） was developed based on the original anaerobic tank of a sewage treatment plant in Hebei Procince. Aerobic granular sludge was successfully cultivated in continuous flow mode with low-concentration municipal sewage as substrate, and the morphology, structural characteristics, pollutant removal performance and microbial community structure changes of granular sludge were studied. Results showed that the granular sludge formed by the pilot system had clear outline, regular spherical and ellipsoidal shape, and the average diameter increased from 28.9 μm to 90.1 μm. Granules with diameters greater than 100 and 200 μm accounted for 47.8% and 9.4%,respectively. Moreover, the mechanical strength of granular sludge cultured in pilot system was much higher than that of inoculated sludge. The average NH 4 + -N concentrations in effluent of series Ⅰ and Ⅱ were 1.3 and1.0 mg·L -1 , respectively, and the average TN concentrations in effluent of series Ⅰ and Ⅱ were 9.9 and 9.1 mg·L -1 ,respectively. Thus the system had a satisfactory nitrogen removal performance. Furthermore, the highthroughput pyrosequencing showed a significant enrichment of Methylophilaceae and Methylotenera at genus level, implying that aerobic denitrification pathway might play an important role in nitrogen removal.
