Papers by Keyword: Eutrophication

Abstract: Human-induced water nutrient enrichment, termed "cultural eutrophication", spurs algae proliferation. This study proposes removing excess cyanobacterial biomass, or blue-green algae, for biofuel production. The resultant digestate serves as organic and mineral fertilizer. Investigating bio-methanogenesis, the study examines reactions for biogas production from BGA, analyzing its chemical and physical properties. This eco-friendly approach, utilizing excess organic matter from algal blooms, ensures sustainable resource utilization. The viability of utilizing cyanobacterial biomass underscores its ecological and economic importance. This paper establishes safe cyanobacterial biomass processing principles, offering a comprehensive technological framework for methane and fertilizer production from various substrates.

Abstract: Phosphorus is a non-renewable source and due to its high levels of phosphorus in water body may lead to eutrophication problems. It may come from many sources such as industry, agriculture and also from wastewater treatment plant. Large excessive of phosphorus may increase the purification cost and serious water quality problem because of the effect of algae toxin in water. Conventional wastewater treatment plant (WWTP) requires lot of cost such as labour, capital and maintenance costs. Therefore, the lab-scale aerated steel slag filter (ASSF) emerged as an alternative method to remove phosphorus from water due to its simple and also low cost technology has been developed to overcome this problem. This lab-scale filter has been conducted by using synthetic wastewater for an eight weeks starting from 19 March until 4^th May 2014. This study is to investigate the effect of pH range from 4.5 to 7.5 and temperature for phosphorus removal mechanism. From this study, result shows that lab-scale ASSF achieve about 90% of phosphorus removal at pH 5.0. Based on X-ray fluorescence (XRF) analysis, the steel slag is rich in Ca, Al and Fe which is enhance the P removal with the influence of pH for precipitation mechanism process in this experiment.

Abstract: To explore NOx mitigation strategies in Chinese cement industry systematically, a material flow analysis was developed. The realistic output of cement production in China were identified and quantified. The inventory data of Chinese cement production were selected without denitration technology applications at that time. Then the life cycle impact assessment (LCIA) results were calculated with the principal of ISO 14040 and ISO 14044 of Life Cycle Assessment. The impact categories of global warming potential (GWP), acidification potential (AP), eutrophication potential (EP), photochemical oxidant formation potential (POCP), and human toxicity potential (HTP) were used to calculate environmental impact. The results showed that the NOx emission was the major environmental damages and the following was CO₂ emission. This argument disagreed with the view that CO₂ emission was the major contributor of environmental load. The reason is that the NOx emission is far over the international level due to few denitration technology applications. In the assumption of selective non-catalytic reduction (SNCR) technology applications, there is still large emission mitigation potential according to the target scenario analysis. The application of selective catalytic reduction (SCR) technology with higher deNOx efficiency and the roadmap of deNOx of Chinese cement industry were also discussed. The SNCR technology with the auxiliary of SCR development over the coming decades will be decisive for the roadmaps of Chinese cement industry to reach deeper NOx emission cuts.

Abstract: Water pollution is a key environmental problem affecting modern day China. Increased human population, agricultural and advanced industrial activities present a complex multiple problems impacting water resource across China. This situation is more pronounced in Tianjing Lake, Tiacang City. Engineered in April 2012, the lake exemplifies severe eutrophication problems. Constructed for recreational uses, the lake plays a vital role in the economic and sociopolitical development of Tiacang City. As a result, the Tianjing Lake water transfer project was carried out in order to improve water quality and alleviate eutrophication. The project considered major field observations that monitored the lake’s nutrients concentrations (TN, TP, NH4, COD Mn) before and after water diversions. Results showed that the effects of water transfer on the overall water quality improvement in the lake seemed heterogeneous. The observed heterogeneity is as a result of the lake’s hydrodynamic conditions influenced by inflow tributaries. However, poor water movement resulting from the lack of outlet to actively expel pollutants may be a key factor compounding the lake’s internal nutrients management. This, however, dictates the engineering of additional flow directions in order to ensure better exchanges and additional nutrients removal through the expulsion via the outlet to improve water quality and sustain ecosystem health. Hence, this study provides useful information necessary to better understand the complex hydrodynamic and mass transport processes in the Tianjing Lake and present a road-map for future management decision-making.

Abstract: In order to study combination effect of aquatic plants for the purification of eutrophic wastewater, research was carried out in greenhouse with water hyacinth (Eichhornia crassipes), hornwort (Ceratophyllum demersum L) an water milfoil (Myriophyllum verticillatum L). In the treatment of water hyacinth + water milfoil , the removal efficiency of ammonium nitrogen (NH₄⁺-N), nitrite nitrogen (NO₃^--N) , total nitrogen (TN), total phosphorus (TP) and COD was 74.7%, 61.7%, 65.6%, 73.8% and 50.8% respectively. And that of water hyacinth + hornwort was 79.0%, 52.6%, 67.5%, 46.2% and 56.9%. The combination of different aquatic plants have better removal efficiency than single species. Water milfoil showed good removal ability for the eutrophication pollutants, such as nitrogen and phosphorus, while hornwort was good at the purification of COD.

Abstract: Butterfly Lake provides an important function of ecological environment and campus service for Guangdong Ocean University. Based on the data which were collected in March,May, September and December in 2013, the water environment quality of Butterfly Lake was assessed. The results show that the key pollutant of Butterfly Lake is total phosphorus (TP). The average concentration of TP is worse than the national quality standards for Class V. The water quality appears an obvious difference in different monitoring time. In September the water quality is the best. The average of single parameter pollution index (Sj) is 0.75 and the water quality belongs to good environment area. The average of integrated parameter pollution index (WQI) is 1.76 and the water quality belongs to light pollution area. In December the water quality is the worst. Sj and WQI is 1.14 and 3.14. The water quality belongs to light pollution area and moderate pollution area, respectively. The comprehensive trophic state index is 70.38 in December. The eutrophication level is hyper eutropher. The other monitoring time belongs to middle eutropher. In order to improve the water quality of Butterfly Lake,the valid measure is to strengthen the management of wastewater discharge from the laboratory and the dormitory.

Abstract: This study analyzes the effectiveness of a constructed wetland, including an improved distribution channel, to deal with the eutrophication of water in an urban lake; it was constructed at a conference center in Beijing, China. The improved distribution channel was designed to achieve two complementary objectives for the operation of a constructed wetland: (1) to delay the clogging of a constructed wetland with organic material and (2) to evenly distribute water in the constructed wetland. When backwashing of the improved distribution channel was done, backwashed water flowed onto the surface of the constructed wetland instead of into the sewage pipe networks to reduce the loss of water and supply nutritive matter for wetland plants. Two principles of the design were based on conserving water and on balancing the total phosphorus and were innovatively applied to guide the process design. After 5 years of operation, the eutrophicated water remediation system was found to have successfully improved the water quality of the constructed wetland by reducing total phosphorus, chemical oxygen demand with permanganate index, and total nitrogen and by efficiently delaying blockage of the constructed wetlands by organic materials.

Abstract: The phytoplankton blooms in the tributary bays have become the most serious environmental problem in Three Gorge Reservoir (TGR), China. In order to understand the mechanism of those phytoplankton blooms, the factors to affect the eutrophication and Phytoplankton blooms have been summarized. Generally, in lakes eutrophication is a natural evolutionary process, which is affected by light, temperature, nutrients, predation, migration and stratification. Recent decade's human activities played a role to promote this evolution but not to change the evolutionary direction. However, in the TGR, the changed hydrodynamics caused by the TGD are considered to be the most important triggers to the phytoplankton blooms, especially the longer residence time, thermal density currents and stratification.

Abstract: To do a research about raw water eutrophication of water plants in Hangzhou, samples of raw water in Jiuxi, Xiangfu, Nanxing, Qingtai Plant were collected and analyzed to get more than 10 water quality indexes. Turbidity, DO, COD, TN, NH₃-N and CHL-a serving as example. supported by GIS, integrated fuzzy evaluations of raw water eutrophication in July and December were completed applying entropy weight method. The result shows that in terms of the nutrient degree, Xiangfu is the most qualified while the least one is Qingtai. Overall, raw water in December is of higher quality than July.

Abstract: According to the survey data of water quality from 2010 of fifteen monitoring sites which in the area of artificial reefs, one mass index of water quality evaluation method, comprehensive quality index method of Water quality and eutrophication level index method were used to analyze the water quality status in Haizhou Bay. The results shows that, each site BOD₅, COD, DIN accord with standard of sea water quality class 1. DIP mostly belong to 2 class standard; In addition to four monitoring sites’ water integrated quality in the slight pollution status for grade 3, the rest of the eleven regions of the sea water is relatively clean for grade 2; This sea water’s N/P maintain the balance basically, In addition to a site appears eutrophication phenomenon, most are in low and medium nutrient level.