The primary objective of this study was to design and size a sustainable sanitation solution for the Ndiebene Gandiol 1 school located in the eponymous commune in northern Senegal. Field investigations led to the coll...The primary objective of this study was to design and size a sustainable sanitation solution for the Ndiebene Gandiol 1 school located in the eponymous commune in northern Senegal. Field investigations led to the collection of wastewater samples. Their analysis revealed specific pollutant loads, including loads of BOD5 3.6966 kgO<sub>2</sub>/day and COD of 12.8775 kgO<sub>2</sub>/day, which were central to the design phase. Following a rigorous assessment of the existing sanitation infrastructure, constructed wetland (CWs) emerged as the most appropriate ecological solution. This system, valued for its ability to effectively remove contaminants, was tailored to the specific needs of the site. Consequently, the final design of the filter extends over 217.16 m<sup>2</sup>, divided into two cells of 108.58 m<sup>2</sup> each, with dimensions of 12.77 m in length and 8.5 m in width. The depth of the filtering medium is approximately 0.60 m, meeting the standards while ensuring maximized purification. Typha, an indigenous and prolific plant known for its purification abilities, was selected as the filtering agent. Concurrently, non-crushed gravel was chosen for its proven filtration capacity. This study is the result of a combination of scientific rigor and design expertise. It provides a holistic view of sanitation for Ndiebene Gandiol. The technical specifications and dimensions of the constructed wetland filter embody an approach that marries indepth analysis and practical application, all aimed at delivering an effective and long-lasting solution to the local sanitation challenges. By integrating precise scientific data with sanitation design expertise, this study delivers a holistic solution for Ndiebene Gandiol. The detailed dimensions and specifications of the constructed wetland filter reflect a methodology that combines meticulous analysis with practical adaptation, aiming to provide an effective and sustainable response to the challenges of rural and school sanitation in the northern region of Senegal.展开更多
The overarching goal of this study is to offer an effective and sustainable solution to the challenges of sanitation in rural and school settings in the northern region of Senegal. The study explores a wastewater trea...The overarching goal of this study is to offer an effective and sustainable solution to the challenges of sanitation in rural and school settings in the northern region of Senegal. The study explores a wastewater treatment approach based on phytoremediation, with a particular focus on the use of horizontally-flowing reed bed filters. Furthermore, it aims to adapt and optimize these systems for the specific needs of Senegal, focusing on wastewater in school environments. Thus, we constructed a horizontally-flowing reed bed filter, planted with Typha, at the Ndiébène Gandiol school in Senegal. We will investigate the efficiency of wastewater treatment by this horizontally-flowing reed bed filter, emphasizing the role of the plant used: Typha. The filter is described in detail, specifying its dimensions, its composition of flint gravel, and the choice of plants, namely Typha. The experimental protocol is detailed, describing the sampling at the entrance and exit of the filter to evaluate water quality. The parameters analyzed include Chemical Oxygen Demand (COD), Biochemical Oxygen Demand over 5 days (BOD5), suspended solids, ammonium, nitrates, phosphates, pH, conductivity, and fecal coliforms. The results indicate a significant improvement in water quality after treatment. COD, BOD5, suspended solids, and fecal coliforms are greatly reduced, thus demonstrating the efficacy of the Typha filter. However, nitrate concentrations remain relatively stable, suggesting room for improvement in their elimination. A perspective of reuse of the treated water is considered, showing that the effluents from the planted filter meet Senegalese and international standards for irrigation. The findings suggest that these waters could be used for a variety of crops, thereby reducing the pressure on freshwater resources. In conclusion, the Typha-based filtration system shows promising results for improving water quality in this region of Senegal. However, adjustments are necessary for more effective nitrate removal. This study paves the way for sustainable use of treated wastewater for irrigation, thus contributing to food security and the preservation of water resources.展开更多
Confronted with the challenge of wastewater management, particularly in the school environment of Senegal, our study set out to achieve multiple objectives. Following field surveys, laboratory analyses of wastewater s...Confronted with the challenge of wastewater management, particularly in the school environment of Senegal, our study set out to achieve multiple objectives. Following field surveys, laboratory analyses of wastewater samples were carried out, revealing a significant pollutant load. In the community of Gandiol, near Saint-Louis (Senegal), the school of Ndiebene Gandiol 1 faces significant sanitation challenges. Our study aimed to address this issue by using a constructed filter composed of two filtering bed cells measuring 12 × 8.5 m, preceded by a septic tank. We particularly focused on the influence of Vetiver;a plant chosen for its purification potential. Our analyses showed remarkable efficiency of the filter. Elimination rates reached 95% for 5-Day Biochemical Oxygen Demand (BOD5), 91% for Chemical Oxygen Demand (COD), and 92% for SS, far exceeding the Senegalese standards set at 50 mg/L, 200 mg/L, and 40 mg/L, respectively. Furthermore, the concentration of fecal coliforms was reduced to 176 FCU/100mL, well below the Senegalese threshold of 2000 FCU/100mL and close to the World Health Organization’s (WHO) recommendation of 1000 FCU/100mL. However, despite these promising results, some parameters, particularly the concentration of certain pollutants, approached the thresholds defined by European legislation. For example, for Suspended Solids (SS), the post-treatment level of 3 mg/L was well below the Senegalese standard but edged close to the European minimum of 10 mg/L. In conclusion, the Vetiver filter demonstrated a remarkable ability to treat school wastewater, offering high pollutant elimination percentages. These results suggest significant opportunities for the reuse of treated water, potentially in areas such as irrigation, though some adjustments may be necessary to meet the strictest standards such as those of the European union (EU).展开更多
This study examined the application of co-benefit-type wastewater treatment technology in the fish-processing industry. Given that there was a dearth of information on fish-processing industrial wastewater in Indonesi...This study examined the application of co-benefit-type wastewater treatment technology in the fish-processing industry. Given that there was a dearth of information on fish-processing industrial wastewater in Indonesia, site surveys were conducted. For the entire fish-processing industry throughout the country, the dissemination rate of wastewater treatment facilities was less than 50%. Using a co-benefit approach, a real-scale swim-bed technology (SBT) and a system combining an anaerobic baffled reactor (ABR) with SBT (ABR–SBT) were installed in a fishmeal processing factory in Bali, Indonesia, and the wastewater system process performance was evaluated. In a business-as-usual scenario, the estimated chemical oxygen demand load and greenhouse gas (GHG) emissions from wastewater from the Indonesian fish-processing industry were 33 000 tons per year and 220 000 tons of equivalent CO_(2) per year, respectively. On the other hand, the GHG emissions in the co-benefit scenarios of the SBT system and ABR–SBT system were 98 149 and 26 720 tons per year, respectively. Therefore, introducing co-benefit-type wastewater treatment to Indonesia’s fish-processing industry would significantly reduce pollution loads and GHG emissions.展开更多
[Objective] The research aimed to study influence factors of phosphorus removal by chemical method in sewage treatment system. [ Method] In different reaction systems, removal effect of the phosphorus in sewage by dos...[Objective] The research aimed to study influence factors of phosphorus removal by chemical method in sewage treatment system. [ Method] In different reaction systems, removal effect of the phosphorus in sewage by dosing lime and influence of the constraint factor were stud- ied. [ Result] Lime precipitation method treating high-concentration phosphorus wastewater could not only decline cost of phosphorus removal by chemical method, but also reach better treatment effect under suitable stirring and precipitation conditions by controlling alkalinity and pH. Phosphor- us content of chemical sludge after treatment could reach 9% -12%, with higher recyclable value. E Conclusion] Lime method treating phosphorus- rich sewage was more economic than low-concentration phosphorus sewage, and had very great potential for recycling phosphorus.展开更多
With the development of medicine,people are becoming more and more aware of the quality of medical water supply,such as dial ysis water,dental water,preparation water,operating room water,supply room water.Therefore,P...With the development of medicine,people are becoming more and more aware of the quality of medical water supply,such as dial ysis water,dental water,preparation water,operating room water,supply room water.Therefore,People are constantly improving the water treatment system and its standardized,and the demand for dialysis water is also becoming more and more strict.Hemodialysis is an effective means of maintaining the life of renal failure patients,120~180L water will be used for a conventional dialysis treatment,and high flux dialysis will consume more.展开更多
This paper analyses the capital costs, power consumption and operation costs of municipal wastewater land treatment systems, including rapid infiltration, slow-rate infiltration, overflow and constructed wetland, by m...This paper analyses the capital costs, power consumption and operation costs of municipal wastewater land treatment systems, including rapid infiltration, slow-rate infiltration, overflow and constructed wetland, by means of series engineering design. The results show that land treatment can save 50-70% of capital costs, 80-90% of power and 75-85% of operation costs when compared with secondary treatment.展开更多
This paper elucidated the necessity and possibility of developing the technology of land treatment on the basis of the analysis of shortage and pollution status of water resources in China.The historical development o...This paper elucidated the necessity and possibility of developing the technology of land treatment on the basis of the analysis of shortage and pollution status of water resources in China.The historical development of this technology in the world was briefly reviewed and the distinction between land treatment and conventional wastewater irrigation was discussed in details. The fundamental characteristics and functions as well as the integrity and compatibility of this ecological engineering were also summarized. It was finally concluded that this technology for wastewater treatment has broad prospects of application in China.展开更多
This paper uses a prediction model of groundwater pollution based on the experiments in the laboratory and in field .The model, which was tested and calibrated by the field observated data ,satisfactorily simulated th...This paper uses a prediction model of groundwater pollution based on the experiments in the laboratory and in field .The model, which was tested and calibrated by the field observated data ,satisfactorily simulated the field conditions in land treatment system of wastewater . Particularly , the model can provide the reliable pollution prediction of heavy metals , organisms and nitrogen . The model was used to predict the groundwater pollution caused by the land treatment system in the region of North China . The calibration of the model showed that correlation coefficients between the tested and predictive data of Cr6+. As3+, organism and NH4+ could reach 0.990, which proved that the model possessed the realistic instructive significance for design and use of wastewater land treatment systems .展开更多
[Objective] The research aimed to study nitrogen removal effect of the land treatment process on reclaimed water. [Method] By using land treatment system, reclaimed water which reached one-level A standard was conduct...[Objective] The research aimed to study nitrogen removal effect of the land treatment process on reclaimed water. [Method] By using land treatment system, reclaimed water which reached one-level A standard was conducted advanced processing, and nitrogen removal efficiency of the effluent was inspected. [ Result] There was a positive correlation between organic matter content of the soil medium and nitrogen removal effect. With appropriate soil medium, TN and NH3-N could obtain the removal efficiency of more than 90% and 75% respectively, and they could be removed at 30 and 10 cm height of soil medium respectively with land treatment system to treat reclaimed water. [ Conclusion ] The research provid- ed theoretical basis for application of the land treatment system into nitrogen removal of the reclaimed water.展开更多
With the rapid growth of the aging population,pelvic floor dysfunction(PFD)has become a new type of high‑incidence disorder.This disorder can be caused by injury,functional deterioration,or coordination disorders of p...With the rapid growth of the aging population,pelvic floor dysfunction(PFD)has become a new type of high‑incidence disorder.This disorder can be caused by injury,functional deterioration,or coordination disorders of pelvic support structures,such as pelvic floor muscles,connective tissues,and pelvic floor muscle fiber.The symptoms can include dyssynergic defecation,fecal incontinence,overactive bladder,urinary incontinence,pelvic organ prolapse,hemorrhoids,sexual dysfunction,chronic urinary retention,and chronic pelvic pain.PFD often presents itself as a combination of symptoms involving urological,gynecological,anorectal,and psychological aspects.Under such circumstances,the development of multidisciplinary integrative diagnosis for PFD has become a trend.展开更多
We investigated the communities of ammonia-oxidizing bacteria (AOB) in activated sludge collected from eight wastewater treatment systems using polymerase chain reaction (PCR) followed by terminal restriction frag...We investigated the communities of ammonia-oxidizing bacteria (AOB) in activated sludge collected from eight wastewater treatment systems using polymerase chain reaction (PCR) followed by terminal restriction fragment length polymorphism (T-RFLP), cloning, and sequencing of the α-subunit of the ammonia monooxygenase gene (amoA). The T-RFLP fingerprint analyses showed that different wastewater treatment systems harbored distinct AOB communities. However, there was no remarkable difference among the AOB T- RFLP profiles from different parts of the same system. The T-RFLP fingerprints showed that a full-scale wastewater treatment plant (WWTP) contained a larger number of dominant AOB species than a pilot-scale reactor. The source of influent affected the AOB community, and the WWTPs treating domestic wastewater contained a higher AOB diversity than those receiving mixed domestic and industrial wastewater. However, the AOB community structure was little affected by the treatment process in this study. Phylogenetic analysis of the cloned amoA genes clearly indicated that all the dominant AOB in the systems was closely related to Nitrosomonas spp. not to Nitrosospira spp. Members of the Nitrosomonas oligotropha and Nitrosomonas communis clusters were found in all samples, while members of Nitrosomonas europaea cluster occurred in some systems.展开更多
On the basis of ecological principles including holistic optimization, cycling and regeneration, and regional differentiation, land treatment systems (LTSs) for municipal wastewater were continuously explored and upda...On the basis of ecological principles including holistic optimization, cycling and regeneration, and regional differentiation, land treatment systems (LTSs) for municipal wastewater were continuously explored and updated in the western Shenyang area and the Huolinhe area, China. Intensified pretreatment, addition of a man-made soil filtration layer, and use of an ecologically diversified secondary plant cover were proved to be technically feasible. Hydraulic loading was determined according to the assimilation capacity of soil ecosystems, thus ensuring safe operation of wastewater treatment. This modernized and alternative approach to wastewater treatment had been widely applied in middle-sized and small cities and towns of Northeast China, and these innovative systems in some areas had indicated favorable ecological, social, and economic benefits.展开更多
The rate of nitrous oxide emission from a laboratory sequence batch reactor (SBR) wastewater treatment system using synthetic wastewater was measured under controlled conditions. The SBR was operated in the mode of 4 ...The rate of nitrous oxide emission from a laboratory sequence batch reactor (SBR) wastewater treatment system using synthetic wastewater was measured under controlled conditions. The SBR was operated in the mode of 4 h for aeration, 3.5 h for stirring without aeration, 0.5 h for settling and drainage, and 4 h of idle. The sludge was acclimated by running the system to achieve a stable running state as indicated by rhythmic changes of total N, dissolved oxygen, chemical oxygen demand, NO^-_2, NO^-_3, NH^+_4, pH, and N2O. Under the present experimental conditions measured nitrous oxide emitted from the off-gas in the aerobic and anaerobic phases, respectively, accounted for 8.6%-16.1% and 0-0.05% of N removed, indicating that the aerobic phase was the main source of N2O emission from the system. N2O dissolved in discharged water was considerable in term of concentration. Thus, measures to be developed for the purpose of reducing N2O emission from the system should be effective in the aeration phase.展开更多
In piezoceramic ultrasonic devices,the piezoceramic stacks may fail permanently or function improperly if their working temperatures overstep the Curie temperature of the piezoceramic material.While the end of the hor...In piezoceramic ultrasonic devices,the piezoceramic stacks may fail permanently or function improperly if their working temperatures overstep the Curie temperature of the piezoceramic material.While the end of the horn usually serves near the melting point of the molten metal and is enclosed in an airtight chamber,so that it is difficult to experimentally measure the temperature of the transducer and its variation with time,which bring heavy difficulty to the design of the ultrasonic molten metal treatment system.To find a way out,conjugate heat transfer analysis of an ultrasonic molten metal treatment system is performed with coupled fluid and heat transfer finite element method.In modeling of the system,the RNG model and the SIMPLE algorithm are adopted for turbulence and nonlinear coupling between the momentum equation and the energy equation.Forced air cooling as well as natural air cooling is analyzed to compare the difference of temperature evolution.Numerical results show that,after about 350 s of working time,temperatures in the surface of the ceramic stacks in forced air cooling drop about 7 K compared with that in natural cooling.At 240 s,The molten metal surface emits heat radiation with a maximum rate of about 19 036 W/m2,while the heat insulation disc absorbs heat radiation at a maximum rate of about 7922 W/m2,which indicates the effectiveness of heat insulation of the asbestos pad.Transient heat transfer film coefficient and its distribution,which are difficult to be measured experimentally are also obtained through numerical simulation.At 240 s,the heat transfer film coefficient in the surface of the transducer ranges from–17.86 to 20.17 W/(m2?K).Compared with the trial and error method based on the test,the proposed research provides a more effective way in the design and analysis of the temperature control of the molten metal treatment system.展开更多
A new water treatment system based on material circulation was constructed for purification of naturally polluted pond water in an aquarium. The water treatment system consisted of microbial columns with different flo...A new water treatment system based on material circulation was constructed for purification of naturally polluted pond water in an aquarium. The water treatment system consisted of microbial columns with different flow rates (1.8 L/min/column in 6-columns unit and 2.9 L/min/column in 3-columns unit). Two hundred liters of water from a naturally polluted pond were treated for 14 days using the water treatment system. After treatment, the COD, TC, and TN had been reduced by up to 19.2%, 14.4%, and 20.1%, respectively. The bacterial biomass in the 3-columns unit was 7-fold higher than that in the 6-columns unit, and PCR-DGGE analysis showed slightly different bacterial communities between the two columns (<86%). The new water treatment system also worked efficiently in a fish-cultivated aquatic environment, with TC and TN removal rates of 190 mg/week and 260 mg/week, respectively.展开更多
Since conventional water treatment is not affordable in developing countries,looking for locally available and alternative treatment options is mandatory.Removal of fluoride and phosphate can be achieved by designing ...Since conventional water treatment is not affordable in developing countries,looking for locally available and alternative treatment options is mandatory.Removal of fluoride and phosphate can be achieved by designing appropriate filtration media from different materials such as sand,calcined clay,pumice,scoria and bone char.This study was designed to determine the removal efficiency of these locally available filter media with respect to detention time and pH.The filtration apparatuses(tank)were filled separately with stone,gravel with grain size 0.6-4.75 mm and 40 cm deep,sand(ES=0.15-0.35 mm and UC=1.5-3),calcined clay,pumice,scoria and bone char with grain size 0.25-0.5 inch.Water samples were prepared using glass bottles with fluoride concentrations of 6 and 8 mg/l and phosphate concentration of 4 mg/1.Laboratory analysis was carried out before and after filtration to determine the removal efficiency of each medium.It was found that the highest removal of fluoride was achieved by bone char(89.65%),followed by pumice(82.4%).However,bone char has rather increased the concentration of phosphate by 63.8%.Sand was the most efficient media to remove phosphate,managing to remove by 70%.Therefore,it is an attractive option to use these locally available,environmental friendly and appropriate technologies for efficient removal of both fluorine and phosphate at the household or community water treatment level.展开更多
Nitrogen removal is a critical process in water treatment plants(WIPs)and wastewater treatment plants(WWTPs).The recent discovery of a novel bacterial process,complete ammonia oxidation(comammox,CMX),has refuted a cen...Nitrogen removal is a critical process in water treatment plants(WIPs)and wastewater treatment plants(WWTPs).The recent discovery of a novel bacterial process,complete ammonia oxidation(comammox,CMX),has refuted a century-long perception of the two-step conversion of NH3to NO3-.Compared with canonical nitrifiers,CMX bacteria offer undeniable advantages,such as a high growth yield propensity and adaptability to nutrient-and growth-limiting conditions,which collectively draw attention to validate the aptness of CMX bacteria to wastewater treatment.As there has been no comprehensive review on the relevance of CMX bacteria for sustainable water and wastewater treatment,this review is intended to discuss the roles and applications of CMX in the removal of nitrogen and pollutants from water and wastewater.We took into account insights into the metabolic versatilities of CMX bacteria at the clade and subclade levels.We focused on the distribution of CMX bacteria in engineered systems,niche differentiation,co-occurrence and interactions with cano nical nitrifiers for a better understanding of CMX bacteria in terms of their ecophysiology.Conceptualized details on the reactor adaptability and stress response of CMX bacteria are provided.The potential of CMX bacteria to degrade micropollutants either directly or co-metabolically was evaluated,and these insights would be an indispensable advantage in opening the doors for wider applications of CMX bacteria in WWTPs.Finally,we summarized future directions of research that are imperative in improving the understanding of CMX biology.展开更多
Development of a technology that can reduce the odor of liquid swine manure during agitation and land application could prove beneficial to the swine industry. The purpose of this study was to evaluate a commercial oz...Development of a technology that can reduce the odor of liquid swine manure during agitation and land application could prove beneficial to the swine industry. The purpose of this study was to evaluate a commercial ozone treatment system for swine slurry under production scale conditions. The facility used for this study was a curtain sided finishing building housing 500 grow–finish market hogs located over a manure pit measuring 12.2 m wide × 25.9 m long × 2.4 m deep with a total pit capacity of 770,142 l, containing 577,607 l. The system evaluated exposes air to ultra-violet light creating O3. The O3 is then injected into slurry at a rate of 851.6 l/min. treating 51,097 l/h. In this study the entire pit contents were treated every 11.3 h. At 0, 24, 48, and 96 h two slurry samples were collected with a 3.05 m probe and six air sample bags were collected via a vacuum pump. No significant differences were detected in slurry samples between time periods. Mean slurry values were 13.6 ± 4.6% solids dry wt., 850 ± 70 mg/l settable solids, 54,200 ± 4384 mg/l total suspended solids, 61,050 ± 12,657 mg/l chemical oxygen demand, 0.86 ± 0.14%N, 0.49 ± 0.27%P, 0.45 ± 0.01%K and dissolved oxygen below detection limits. Ammonia concentrations decreased (P = 0.004) from 0 to 96 h. Odor panelists analyzed air samples for intensity at recognition (IR), offensiveness at recognition (OR), intensity at full strength (IFS) and offensiveness at full strength (OFS). Panelists found OR, IFS and OFS were reduced (P < 0.01) at 48 h and 96 h compared to 0 h and IR was reduced (P < 0.04) at 24 h and 48 h and not at 96 h but trended lower (P = 0.12) at 96 h. The system evaluated significantly improved air quality within the building suggesting that odor emanating from swine buildings and odor generated during land application of slurry should be reduced.展开更多
文摘The primary objective of this study was to design and size a sustainable sanitation solution for the Ndiebene Gandiol 1 school located in the eponymous commune in northern Senegal. Field investigations led to the collection of wastewater samples. Their analysis revealed specific pollutant loads, including loads of BOD5 3.6966 kgO<sub>2</sub>/day and COD of 12.8775 kgO<sub>2</sub>/day, which were central to the design phase. Following a rigorous assessment of the existing sanitation infrastructure, constructed wetland (CWs) emerged as the most appropriate ecological solution. This system, valued for its ability to effectively remove contaminants, was tailored to the specific needs of the site. Consequently, the final design of the filter extends over 217.16 m<sup>2</sup>, divided into two cells of 108.58 m<sup>2</sup> each, with dimensions of 12.77 m in length and 8.5 m in width. The depth of the filtering medium is approximately 0.60 m, meeting the standards while ensuring maximized purification. Typha, an indigenous and prolific plant known for its purification abilities, was selected as the filtering agent. Concurrently, non-crushed gravel was chosen for its proven filtration capacity. This study is the result of a combination of scientific rigor and design expertise. It provides a holistic view of sanitation for Ndiebene Gandiol. The technical specifications and dimensions of the constructed wetland filter embody an approach that marries indepth analysis and practical application, all aimed at delivering an effective and long-lasting solution to the local sanitation challenges. By integrating precise scientific data with sanitation design expertise, this study delivers a holistic solution for Ndiebene Gandiol. The detailed dimensions and specifications of the constructed wetland filter reflect a methodology that combines meticulous analysis with practical adaptation, aiming to provide an effective and sustainable response to the challenges of rural and school sanitation in the northern region of Senegal.
文摘The overarching goal of this study is to offer an effective and sustainable solution to the challenges of sanitation in rural and school settings in the northern region of Senegal. The study explores a wastewater treatment approach based on phytoremediation, with a particular focus on the use of horizontally-flowing reed bed filters. Furthermore, it aims to adapt and optimize these systems for the specific needs of Senegal, focusing on wastewater in school environments. Thus, we constructed a horizontally-flowing reed bed filter, planted with Typha, at the Ndiébène Gandiol school in Senegal. We will investigate the efficiency of wastewater treatment by this horizontally-flowing reed bed filter, emphasizing the role of the plant used: Typha. The filter is described in detail, specifying its dimensions, its composition of flint gravel, and the choice of plants, namely Typha. The experimental protocol is detailed, describing the sampling at the entrance and exit of the filter to evaluate water quality. The parameters analyzed include Chemical Oxygen Demand (COD), Biochemical Oxygen Demand over 5 days (BOD5), suspended solids, ammonium, nitrates, phosphates, pH, conductivity, and fecal coliforms. The results indicate a significant improvement in water quality after treatment. COD, BOD5, suspended solids, and fecal coliforms are greatly reduced, thus demonstrating the efficacy of the Typha filter. However, nitrate concentrations remain relatively stable, suggesting room for improvement in their elimination. A perspective of reuse of the treated water is considered, showing that the effluents from the planted filter meet Senegalese and international standards for irrigation. The findings suggest that these waters could be used for a variety of crops, thereby reducing the pressure on freshwater resources. In conclusion, the Typha-based filtration system shows promising results for improving water quality in this region of Senegal. However, adjustments are necessary for more effective nitrate removal. This study paves the way for sustainable use of treated wastewater for irrigation, thus contributing to food security and the preservation of water resources.
文摘Confronted with the challenge of wastewater management, particularly in the school environment of Senegal, our study set out to achieve multiple objectives. Following field surveys, laboratory analyses of wastewater samples were carried out, revealing a significant pollutant load. In the community of Gandiol, near Saint-Louis (Senegal), the school of Ndiebene Gandiol 1 faces significant sanitation challenges. Our study aimed to address this issue by using a constructed filter composed of two filtering bed cells measuring 12 × 8.5 m, preceded by a septic tank. We particularly focused on the influence of Vetiver;a plant chosen for its purification potential. Our analyses showed remarkable efficiency of the filter. Elimination rates reached 95% for 5-Day Biochemical Oxygen Demand (BOD5), 91% for Chemical Oxygen Demand (COD), and 92% for SS, far exceeding the Senegalese standards set at 50 mg/L, 200 mg/L, and 40 mg/L, respectively. Furthermore, the concentration of fecal coliforms was reduced to 176 FCU/100mL, well below the Senegalese threshold of 2000 FCU/100mL and close to the World Health Organization’s (WHO) recommendation of 1000 FCU/100mL. However, despite these promising results, some parameters, particularly the concentration of certain pollutants, approached the thresholds defined by European legislation. For example, for Suspended Solids (SS), the post-treatment level of 3 mg/L was well below the Senegalese standard but edged close to the European minimum of 10 mg/L. In conclusion, the Vetiver filter demonstrated a remarkable ability to treat school wastewater, offering high pollutant elimination percentages. These results suggest significant opportunities for the reuse of treated water, potentially in areas such as irrigation, though some adjustments may be necessary to meet the strictest standards such as those of the European union (EU).
文摘This study examined the application of co-benefit-type wastewater treatment technology in the fish-processing industry. Given that there was a dearth of information on fish-processing industrial wastewater in Indonesia, site surveys were conducted. For the entire fish-processing industry throughout the country, the dissemination rate of wastewater treatment facilities was less than 50%. Using a co-benefit approach, a real-scale swim-bed technology (SBT) and a system combining an anaerobic baffled reactor (ABR) with SBT (ABR–SBT) were installed in a fishmeal processing factory in Bali, Indonesia, and the wastewater system process performance was evaluated. In a business-as-usual scenario, the estimated chemical oxygen demand load and greenhouse gas (GHG) emissions from wastewater from the Indonesian fish-processing industry were 33 000 tons per year and 220 000 tons of equivalent CO_(2) per year, respectively. On the other hand, the GHG emissions in the co-benefit scenarios of the SBT system and ABR–SBT system were 98 149 and 26 720 tons per year, respectively. Therefore, introducing co-benefit-type wastewater treatment to Indonesia’s fish-processing industry would significantly reduce pollution loads and GHG emissions.
文摘[Objective] The research aimed to study influence factors of phosphorus removal by chemical method in sewage treatment system. [ Method] In different reaction systems, removal effect of the phosphorus in sewage by dosing lime and influence of the constraint factor were stud- ied. [ Result] Lime precipitation method treating high-concentration phosphorus wastewater could not only decline cost of phosphorus removal by chemical method, but also reach better treatment effect under suitable stirring and precipitation conditions by controlling alkalinity and pH. Phosphor- us content of chemical sludge after treatment could reach 9% -12%, with higher recyclable value. E Conclusion] Lime method treating phosphorus- rich sewage was more economic than low-concentration phosphorus sewage, and had very great potential for recycling phosphorus.
基金Guangdong Obers Blood Purification Aca demician Work station(2013B090400004)Science and technology plan project of Guangdong industrial high and new technology field(2013B010203019)+3 种基金Guangzhou entrepreneurial leader talent/LCY201215Guangdong Inno vation Fund Project(2014A010101123)Guangdong Provincial Center for clinical en gineering of blood purification(507204531040)Guangdong University blood purification technology and Engineering Research Center(GCZX-A1104)
文摘With the development of medicine,people are becoming more and more aware of the quality of medical water supply,such as dial ysis water,dental water,preparation water,operating room water,supply room water.Therefore,People are constantly improving the water treatment system and its standardized,and the demand for dialysis water is also becoming more and more strict.Hemodialysis is an effective means of maintaining the life of renal failure patients,120~180L water will be used for a conventional dialysis treatment,and high flux dialysis will consume more.
文摘This paper analyses the capital costs, power consumption and operation costs of municipal wastewater land treatment systems, including rapid infiltration, slow-rate infiltration, overflow and constructed wetland, by means of series engineering design. The results show that land treatment can save 50-70% of capital costs, 80-90% of power and 75-85% of operation costs when compared with secondary treatment.
文摘This paper elucidated the necessity and possibility of developing the technology of land treatment on the basis of the analysis of shortage and pollution status of water resources in China.The historical development of this technology in the world was briefly reviewed and the distinction between land treatment and conventional wastewater irrigation was discussed in details. The fundamental characteristics and functions as well as the integrity and compatibility of this ecological engineering were also summarized. It was finally concluded that this technology for wastewater treatment has broad prospects of application in China.
文摘This paper uses a prediction model of groundwater pollution based on the experiments in the laboratory and in field .The model, which was tested and calibrated by the field observated data ,satisfactorily simulated the field conditions in land treatment system of wastewater . Particularly , the model can provide the reliable pollution prediction of heavy metals , organisms and nitrogen . The model was used to predict the groundwater pollution caused by the land treatment system in the region of North China . The calibration of the model showed that correlation coefficients between the tested and predictive data of Cr6+. As3+, organism and NH4+ could reach 0.990, which proved that the model possessed the realistic instructive significance for design and use of wastewater land treatment systems .
基金Supported by Research and Demonstration of the Ecological Construction and Restoration Technology for Yongding River, China(D090409004009004)
文摘[Objective] The research aimed to study nitrogen removal effect of the land treatment process on reclaimed water. [Method] By using land treatment system, reclaimed water which reached one-level A standard was conducted advanced processing, and nitrogen removal efficiency of the effluent was inspected. [ Result] There was a positive correlation between organic matter content of the soil medium and nitrogen removal effect. With appropriate soil medium, TN and NH3-N could obtain the removal efficiency of more than 90% and 75% respectively, and they could be removed at 30 and 10 cm height of soil medium respectively with land treatment system to treat reclaimed water. [ Conclusion ] The research provid- ed theoretical basis for application of the land treatment system into nitrogen removal of the reclaimed water.
文摘With the rapid growth of the aging population,pelvic floor dysfunction(PFD)has become a new type of high‑incidence disorder.This disorder can be caused by injury,functional deterioration,or coordination disorders of pelvic support structures,such as pelvic floor muscles,connective tissues,and pelvic floor muscle fiber.The symptoms can include dyssynergic defecation,fecal incontinence,overactive bladder,urinary incontinence,pelvic organ prolapse,hemorrhoids,sexual dysfunction,chronic urinary retention,and chronic pelvic pain.PFD often presents itself as a combination of symptoms involving urological,gynecological,anorectal,and psychological aspects.Under such circumstances,the development of multidisciplinary integrative diagnosis for PFD has become a trend.
基金supported by the Key Projects in National Science & Technology Pillar Program during the Eleventh Five-Year Plan Period (No.2006BAC19B01-02)the Mega-projects of Science Research for Water (No.2008ZX07313-3)the Program of Introducing Talents of Discipline to Universities
文摘We investigated the communities of ammonia-oxidizing bacteria (AOB) in activated sludge collected from eight wastewater treatment systems using polymerase chain reaction (PCR) followed by terminal restriction fragment length polymorphism (T-RFLP), cloning, and sequencing of the α-subunit of the ammonia monooxygenase gene (amoA). The T-RFLP fingerprint analyses showed that different wastewater treatment systems harbored distinct AOB communities. However, there was no remarkable difference among the AOB T- RFLP profiles from different parts of the same system. The T-RFLP fingerprints showed that a full-scale wastewater treatment plant (WWTP) contained a larger number of dominant AOB species than a pilot-scale reactor. The source of influent affected the AOB community, and the WWTPs treating domestic wastewater contained a higher AOB diversity than those receiving mixed domestic and industrial wastewater. However, the AOB community structure was little affected by the treatment process in this study. Phylogenetic analysis of the cloned amoA genes clearly indicated that all the dominant AOB in the systems was closely related to Nitrosomonas spp. not to Nitrosospira spp. Members of the Nitrosomonas oligotropha and Nitrosomonas communis clusters were found in all samples, while members of Nitrosomonas europaea cluster occurred in some systems.
基金Project supported by the National Natural Science Founds for Distinguished Young Scholars, China (No. 20225722)the Key Programme of the National Natural Science Foundation of China (No. 20337010)
文摘On the basis of ecological principles including holistic optimization, cycling and regeneration, and regional differentiation, land treatment systems (LTSs) for municipal wastewater were continuously explored and updated in the western Shenyang area and the Huolinhe area, China. Intensified pretreatment, addition of a man-made soil filtration layer, and use of an ecologically diversified secondary plant cover were proved to be technically feasible. Hydraulic loading was determined according to the assimilation capacity of soil ecosystems, thus ensuring safe operation of wastewater treatment. This modernized and alternative approach to wastewater treatment had been widely applied in middle-sized and small cities and towns of Northeast China, and these innovative systems in some areas had indicated favorable ecological, social, and economic benefits.
基金Project supported by the National Natural Science Foundation of China (Nos. 40471072 and 30470060) and the Knowledge Innovation Program of Chinese Academy of Sciences (No. KZCX2-413-3-1).
文摘The rate of nitrous oxide emission from a laboratory sequence batch reactor (SBR) wastewater treatment system using synthetic wastewater was measured under controlled conditions. The SBR was operated in the mode of 4 h for aeration, 3.5 h for stirring without aeration, 0.5 h for settling and drainage, and 4 h of idle. The sludge was acclimated by running the system to achieve a stable running state as indicated by rhythmic changes of total N, dissolved oxygen, chemical oxygen demand, NO^-_2, NO^-_3, NH^+_4, pH, and N2O. Under the present experimental conditions measured nitrous oxide emitted from the off-gas in the aerobic and anaerobic phases, respectively, accounted for 8.6%-16.1% and 0-0.05% of N removed, indicating that the aerobic phase was the main source of N2O emission from the system. N2O dissolved in discharged water was considerable in term of concentration. Thus, measures to be developed for the purpose of reducing N2O emission from the system should be effective in the aeration phase.
基金Supported by Beijing Municipal Natural Science Foundation of China(Grant No.3093027)
文摘In piezoceramic ultrasonic devices,the piezoceramic stacks may fail permanently or function improperly if their working temperatures overstep the Curie temperature of the piezoceramic material.While the end of the horn usually serves near the melting point of the molten metal and is enclosed in an airtight chamber,so that it is difficult to experimentally measure the temperature of the transducer and its variation with time,which bring heavy difficulty to the design of the ultrasonic molten metal treatment system.To find a way out,conjugate heat transfer analysis of an ultrasonic molten metal treatment system is performed with coupled fluid and heat transfer finite element method.In modeling of the system,the RNG model and the SIMPLE algorithm are adopted for turbulence and nonlinear coupling between the momentum equation and the energy equation.Forced air cooling as well as natural air cooling is analyzed to compare the difference of temperature evolution.Numerical results show that,after about 350 s of working time,temperatures in the surface of the ceramic stacks in forced air cooling drop about 7 K compared with that in natural cooling.At 240 s,The molten metal surface emits heat radiation with a maximum rate of about 19 036 W/m2,while the heat insulation disc absorbs heat radiation at a maximum rate of about 7922 W/m2,which indicates the effectiveness of heat insulation of the asbestos pad.Transient heat transfer film coefficient and its distribution,which are difficult to be measured experimentally are also obtained through numerical simulation.At 240 s,the heat transfer film coefficient in the surface of the transducer ranges from–17.86 to 20.17 W/(m2?K).Compared with the trial and error method based on the test,the proposed research provides a more effective way in the design and analysis of the temperature control of the molten metal treatment system.
文摘A new water treatment system based on material circulation was constructed for purification of naturally polluted pond water in an aquarium. The water treatment system consisted of microbial columns with different flow rates (1.8 L/min/column in 6-columns unit and 2.9 L/min/column in 3-columns unit). Two hundred liters of water from a naturally polluted pond were treated for 14 days using the water treatment system. After treatment, the COD, TC, and TN had been reduced by up to 19.2%, 14.4%, and 20.1%, respectively. The bacterial biomass in the 3-columns unit was 7-fold higher than that in the 6-columns unit, and PCR-DGGE analysis showed slightly different bacterial communities between the two columns (<86%). The new water treatment system also worked efficiently in a fish-cultivated aquatic environment, with TC and TN removal rates of 190 mg/week and 260 mg/week, respectively.
文摘Since conventional water treatment is not affordable in developing countries,looking for locally available and alternative treatment options is mandatory.Removal of fluoride and phosphate can be achieved by designing appropriate filtration media from different materials such as sand,calcined clay,pumice,scoria and bone char.This study was designed to determine the removal efficiency of these locally available filter media with respect to detention time and pH.The filtration apparatuses(tank)were filled separately with stone,gravel with grain size 0.6-4.75 mm and 40 cm deep,sand(ES=0.15-0.35 mm and UC=1.5-3),calcined clay,pumice,scoria and bone char with grain size 0.25-0.5 inch.Water samples were prepared using glass bottles with fluoride concentrations of 6 and 8 mg/l and phosphate concentration of 4 mg/1.Laboratory analysis was carried out before and after filtration to determine the removal efficiency of each medium.It was found that the highest removal of fluoride was achieved by bone char(89.65%),followed by pumice(82.4%).However,bone char has rather increased the concentration of phosphate by 63.8%.Sand was the most efficient media to remove phosphate,managing to remove by 70%.Therefore,it is an attractive option to use these locally available,environmental friendly and appropriate technologies for efficient removal of both fluorine and phosphate at the household or community water treatment level.
基金supported by the National Natural Science Foundation of China(52000185 and 51878675)Key Research and Development Program of Shandong Province(2019JZZY020308)China Postdoctoral Science Foundation,China(2017M612807)。
文摘Nitrogen removal is a critical process in water treatment plants(WIPs)and wastewater treatment plants(WWTPs).The recent discovery of a novel bacterial process,complete ammonia oxidation(comammox,CMX),has refuted a century-long perception of the two-step conversion of NH3to NO3-.Compared with canonical nitrifiers,CMX bacteria offer undeniable advantages,such as a high growth yield propensity and adaptability to nutrient-and growth-limiting conditions,which collectively draw attention to validate the aptness of CMX bacteria to wastewater treatment.As there has been no comprehensive review on the relevance of CMX bacteria for sustainable water and wastewater treatment,this review is intended to discuss the roles and applications of CMX in the removal of nitrogen and pollutants from water and wastewater.We took into account insights into the metabolic versatilities of CMX bacteria at the clade and subclade levels.We focused on the distribution of CMX bacteria in engineered systems,niche differentiation,co-occurrence and interactions with cano nical nitrifiers for a better understanding of CMX bacteria in terms of their ecophysiology.Conceptualized details on the reactor adaptability and stress response of CMX bacteria are provided.The potential of CMX bacteria to degrade micropollutants either directly or co-metabolically was evaluated,and these insights would be an indispensable advantage in opening the doors for wider applications of CMX bacteria in WWTPs.Finally,we summarized future directions of research that are imperative in improving the understanding of CMX biology.
文摘Development of a technology that can reduce the odor of liquid swine manure during agitation and land application could prove beneficial to the swine industry. The purpose of this study was to evaluate a commercial ozone treatment system for swine slurry under production scale conditions. The facility used for this study was a curtain sided finishing building housing 500 grow–finish market hogs located over a manure pit measuring 12.2 m wide × 25.9 m long × 2.4 m deep with a total pit capacity of 770,142 l, containing 577,607 l. The system evaluated exposes air to ultra-violet light creating O3. The O3 is then injected into slurry at a rate of 851.6 l/min. treating 51,097 l/h. In this study the entire pit contents were treated every 11.3 h. At 0, 24, 48, and 96 h two slurry samples were collected with a 3.05 m probe and six air sample bags were collected via a vacuum pump. No significant differences were detected in slurry samples between time periods. Mean slurry values were 13.6 ± 4.6% solids dry wt., 850 ± 70 mg/l settable solids, 54,200 ± 4384 mg/l total suspended solids, 61,050 ± 12,657 mg/l chemical oxygen demand, 0.86 ± 0.14%N, 0.49 ± 0.27%P, 0.45 ± 0.01%K and dissolved oxygen below detection limits. Ammonia concentrations decreased (P = 0.004) from 0 to 96 h. Odor panelists analyzed air samples for intensity at recognition (IR), offensiveness at recognition (OR), intensity at full strength (IFS) and offensiveness at full strength (OFS). Panelists found OR, IFS and OFS were reduced (P < 0.01) at 48 h and 96 h compared to 0 h and IR was reduced (P < 0.04) at 24 h and 48 h and not at 96 h but trended lower (P = 0.12) at 96 h. The system evaluated significantly improved air quality within the building suggesting that odor emanating from swine buildings and odor generated during land application of slurry should be reduced.