A pilot-scale study of Cryptosporidium-sized microsphere removals from swimming pools via sand filtration

2015 ◽  
Vol 14 (1) ◽  
pp. 109-120 ◽  
Author(s):  
Ping Lu ◽  
James E. Amburgey
Keyword(s):  
Filtration Rate ◽  
Pilot Scale ◽  
Cryptosporidium Species ◽  
High Rate ◽  
Organic Polymer ◽  
Recreational Water ◽  
Sand Filtration ◽  
Polyaluminum Chloride ◽  
Overall Performance ◽  
Over Time

Cryptosporidium species are the most common cause of gastrointestinal illness in treated recreational water venues. In order to protect public health during swimming, Cryptosporidium-sized microsphere removals by high-rate sand filtration with six coagulants were evaluated with a 5.5 m3 pilot-scale swimming pool. A sand filter without coagulation removed 20–63% of Cryptosporidium-sized microspheres. Cryptosporidium-sized microsphere removals exceeded 98% by sand filtration with five of the six tested coagulants. Continuously feeding coagulants A, B, and F (i.e., organic polymers) led to coagulant accumulation in the system and decreased removals over time (<2 days). Coagulant E (polyaluminum chloride) consistently removed more than 90% of microspheres at 30 m/h while the removals dropped to approximately 50% at a filtration rate of 37 m/h. Coagulant C was a chitosan-based product that removed fewer microspheres compared with other products, <75%, under the studied conditions. Results indicated aluminum-based coagulants (coagulants D and E) had an overall performance advantage over the organic polymer based coagulants primarily in terms of their tendency not to accumulate in the water and cease to be effective at improving filter efficiency.

scholarly journals Removals of cryptosporidium parvum oocysts and cryptosporidium-sized polystyrene microspheres from swimming pool water by diatomaceous earth filtration and perlite-sand filtration

2017 ◽  
Vol 15 (3) ◽  
pp. 374-384 ◽  
Author(s):  
Ping Lu ◽  
James E. Amburgey ◽  
Vincent R. Hill ◽  
Jennifer L. Murphy ◽  
Chandra L. Schneeberger ◽  
...  
Keyword(s):  
Cryptosporidium Parvum ◽  
Filtration Rate ◽  
Diatomaceous Earth ◽  
Pilot Scale ◽  
Full Scale ◽  
Swimming Pool ◽  
Swimming Pools ◽  
Sand Filtration ◽  
Sand Filter ◽  
Cryptosporidium Parvum Oocysts

Removal of Cryptosporidium-sized microspheres and Cryptosporidium parvum oocysts from swimming pools was investigated using diatomaceous earth (DE) precoat filtration and perlite-sand filtration. In pilot-scale experiments, microsphere removals of up to 2 log were obtained with 0.7 kg·DE/m2 at a filtration rate of 5 m/h. A slightly higher microsphere removal (2.3 log) was obtained for these DE-precoated filters when the filtration rate was 3.6 m/h. Additionally, pilot-scale perlite-sand filters achieved greater than 2 log removal when at least 0.37 kg/m2 of perlite was used compared to 0.1–0.4 log removal without perlite both at a surface loading rate of 37 m/h. Full-scale testing achieved 2.7 log of microspheres and oocysts removal when 0.7 kg·DE/m2 was used at 3.6 m/h. Removals were significantly decreased by a 15-minute interruption of the flow (without any mechanical agitation) to the DE filter in pilot-scale studies, which was not observed in full-scale filters. Microsphere removals were 2.7 log by perlite-sand filtration in a full-scale swimming pool filter operated at 34 m/h with 0.5 kg/m2 of perlite. The results demonstrate that either a DE precoat filter or a perlite-sand filter can improve the efficiency of removal of microspheres and oocysts from swimming pools over a standard sand filter under the conditions studied.

High-speed filtration using highly porous fiber media for advanced and compact particle removal

2014 ◽  
Vol 14 (5) ◽  
pp. 735-742 ◽  
Author(s):  
Heidi B. Guerra ◽  
Siping Niu ◽  
Kisoo Park ◽  
Youngchul Kim
Keyword(s):  
High Speed ◽  
Filtration Rate ◽  
Polypropylene Fiber ◽  
High Rate ◽  
High Porosity ◽  
Particle Removal ◽  
Polyaluminum Chloride ◽  
Operating Variables ◽  
The Impact ◽  
Highly Porous

Since its recent introduction to the filtration industry, one of the major concerns about the use of fiber in water treatment has been its applicability for high-rate filtration while minimizing the build-up of headloss. In this study, a compact, modular filter employing non-woven, highly porous polypropylene fiber as filter media was investigated for the treatment of turbid water under high filtration rates. The impact of different operating variables such as polyaluminum chloride (PAC) dose and filtration rate on the effluent turbidity and headloss were investigated. Due to the fiber's high porosity, the filter was able to retain solids at a filtration rate of up to 1,500 m/day without headloss. When PAC was added, the effluent turbidity decreased significantly with the lowest observed when the dose was 1 mg/L. Furthermore, the effluent turbidity was found to increase with the filtration rate. During all the experiments, no headloss was observed except when the filtration rate was 2,250 m/day or when the PAC dose was 5 mg/L. In terms of its compactness and applicability at very high filtration rates, the polypropylene fiber filter can have a considerable advantage compared to other filters.

scholarly journals A full-scale study of Cryptosporidium parvum oocyst and Cryptosporidium-sized microsphere removals from swimming pools via sand filtration

2015 ◽  
Vol 52 (1) ◽  
pp. 18-25 ◽  
Author(s):  
Ping Lu ◽  
James E. Amburgey ◽  
Vincent R. Hill ◽  
Jennifer L. Murphy ◽  
Chandra Schneeberger ◽  
...  
Keyword(s):  
Cryptosporidium Parvum ◽  
Initial Dosage ◽  
Pilot Scale ◽  
Full Scale ◽  
Swimming Pool ◽  
High Rate ◽  
Swimming Pools ◽  
Sand Filtration ◽  
Continuous Feeding ◽  
Cryptosporidium Parvum Oocysts

Removal of Cryptosporidium parvum oocysts and Cryptosporidium-sized microspheres was evaluated in full-scale swimming pools via high-rate sand filtration (31–34 m/h) with coagulation. Results showed that at least 90% of C. parvum oocysts and microspheres were removed by filtration with an initial dosage of coagulant B (1.56 mg/L), D (1.9 mg/L or 305 g/m2), or F (1.56 mg/L) from each swimming pool. Filtration with an initial dosage of coagulant E (0.1 mg·Al/L) achieved 82% C. parvum oocyst removal and 97% microsphere removal. Coagulants B and F had a tendency to overdose over time with continuous feeding (based on corresponding pilot-scale experiments) and did not consistently achieve removals greater than 90% in the full-scale trials. As high as 99% of C. parvum oocysts and 98% of microspheres were removed with a continuous dosage of coagulant D. Up to 98% (1.7 log) of C. parvum oocysts and 93% (1.1 log) of microspheres were removed by continuous dosing of coagulant E at 27 m/h. Consistent oocyst and microsphere removal by aluminum-based coagulants (D and E) was achieved under the tested swimming pool conditions.

Viability of nematode eggs in high rate algal ponds: the effect of physico-chemical conditions

2000 ◽  
Vol 42 (10-11) ◽  
pp. 371-374 ◽  
Author(s):  
S. Araki ◽  
J. M. González ◽  
E. de Luis ◽  
E. Bécares
Keyword(s):  
Hydraulic Retention Time ◽  
Pilot Scale ◽  
High Rate ◽  
Sterile Water ◽  
Egg Viability ◽  
High Rate Algal Ponds ◽  
Helminth Eggs ◽  
Physico Chemical ◽  
Nematode Eggs ◽  
Chemical Conditions

The viability of Parascaris equorum eggs was studied in two experimental pilot-scale high-rate algal ponds (HRAPs) working in parallel with 4 and 10 days hydraulic retention time respectively. Semi-permeable bags of cellulose (15000 daltons pore size) were used to study the effect of physico-chemical conditions on the survival of these helminth eggs. Three thousand eggs were used in each bag. Replicates of these bags were submerged for 4 and 10 days in the HRAPs and egg viability was compared with that in control bags submerged in sterile water. After 4 days exposure, 60% reduction in viability was achieved, reaching 90% after 10 days, much higher than the 16% and 25% found in the control bags for 4 and 10 days respectively. Ionic conditions of the HRAP may have been responsible for up to 50–60% of the egg mortality, suggesting that mortality due to the ionic environment could be more important than physical retention and other potential removal factors.

On-site and in situ bioremediation of wood-preservative contaminated groundwater

2000 ◽  
Vol 42 (5-6) ◽  
pp. 371-376 ◽  
Author(s):  
J.A. Puhakka ◽  
K.T. Järvinen ◽  
J.H. Langwaldt ◽  
E.S. Melin ◽  
M.K. Männistö ◽  
...  
Keyword(s):  
Iron Oxidation ◽  
Wood Preservative ◽  
Pilot Scale ◽  
High Rate ◽  
Contaminated Groundwater ◽  
Groundwater Temperature ◽  
In Situ Bioremediation ◽  
Contaminated Aquifer ◽  
Fluidized Bed Process

This paper reviews ten years of research on on-site and in situ bioremediation of chlorophenol contaminated groundwater. Laboratory experiments on the development of a high-rate, fluidized-bed process resulted in a full-scale, pump-and-treat application which has operated for several years. The system operates at ambient groundwater temperature of 7 to 9°C at 2.7 d hydraulic retention time and chlorophenol removal efficiencies of 98.5 to 99.9%. The microbial ecology studies of the contaminated aquifer revealed a diverse chlorophenol-degrading community. In situ biodegradation of chlorophenols is controlled by oxygen availability, only. Laboratory and pilot-scale experiments showed the potential for in situ aquifer bioremediation with iron oxidation and precipitation as a potential problem.

Sustaining Research-Based Practices in Reading

1999 ◽  
Vol 20 (5) ◽  
pp. 263-287 ◽  
Author(s):  
Janette K. Klingner ◽  
Sharon Vaughn ◽  
Marie Tejero Hughes ◽  
Maria Elena Arguelles
Keyword(s):  
Instructional Practices ◽  
High Rate ◽  
Strategic Reading ◽  
School Year ◽  
Wide Range ◽  
Sustained Use ◽  
Development Experience ◽  
Collaborative Strategic Reading ◽  
Research Based Practices ◽  
Over Time

This study examined the extent to which the reading instructional practices learned by a cohort of teachers who participated in an intensive, yearlong professional development experience during the 1994-1995 school year have been sustained and modified over time. Teachers learned three multileveled practices—partner reading, collaborative strategic reading, and making words—that promote gains in reading for students from a wide range of achievement levels. Teachers were observed and interviewed 3 years later to determine the extent to which they continued to implement the practices, the ways in which they modified them, and factors that influenced their sustained use of the practices. With the exception of one teacher, all the teachers sustained one or more of the three practices at a high rate.

Early-career offending trajectories among outlaw motorcycle gang members

2021 ◽  
Author(s):  
Isabella Voce ◽  
Anthony Morgan
Keyword(s):  
Early Adulthood ◽  
Criminal History ◽  
Early Career ◽  
High Rate ◽  
Criminal Enterprise ◽  
Steady Rate ◽  
Criminal Histories ◽  
Offending Trajectories ◽  
History Of ◽  
Over Time

This study examines the criminal histories of outlaw motorcycle gang (OMCG) members during adolescence and early adulthood to determine whether the profile of young members has changed over time. The recorded offence histories of three cohorts of members—those born between 1979 and 1983, 1984 and 1988, and 1989 and 1993—were compared. Seventy-eight percent of OMCG members across all three cohorts had at least one recorded offence between the ages of 12 and 24. The majority of offenders did not desist but continued offending at a steady rate into adulthood. The youngest cohort in the study was more likely than the middle and older cohorts to have a criminal history and follow a high-rate offending trajectory. Members of the youngest cohort were also more likely to have been apprehended for violence and intimidation, weapons and ongoing criminal enterprise offences by their early twenties. These results suggest that OMCGs are recruiting younger members, who are becoming involved in gang-related offending earlier in life, or that individuals with a history of offending are becoming more likely to join or be recruited into OMCGs.

Long-Term Outcomes of Patients with Acromegaly - A Report from the Swedish Pituitary Register

2022 ◽  
Author(s):  
Steinunn Arnardóttir ◽  
Jacob Järås ◽  
Pia Burman ◽  
Katarina Berinder ◽  
Per Dahlqvist ◽  
...  
Keyword(s):  
High Rate ◽  
Hormone Deficiency ◽  
Visual Field Defects ◽  
Mortality Data ◽  
Pituitary Hormone ◽  
Biochemical Control ◽  
Long Term Outcomes ◽  
Over Time

Objective: To describe treatment and long-term outcomes of patients with acromegaly from all health-care regions in Sweden. Design and Methods: Analysis of prospectively reported data from the Swedish Pituitary Register of 698 patients (51% females) with acromegaly diagnosed from 1991-2011. The latest clinical follow-up date was December, 2012, while mortality data were collected for 28.5 years until June, 2019. Results: The annual incidence was 3.7/million; 71% of patients had a macroadenoma, 18% had visual field defects, and 25% had at least one pituitary hormone deficiency. Eighty-two percent had pituitary surgery, 10% radiotherapy and 39% medical treatment. At the 5- and 10-year follow-ups, IGF-I levels were within the reference range in 69% and 78% of patients, respectively. In linear regression the proportion of patients with biochemical control including adjuvant therapy at 10 year follow-up increased over time with 1.23 % per year. The SMR (95% CI) for all patients was 1.29 (1.11-1.49). For patients with biochemical control at the latest follow-up, SMR was not increased, neither among patients diagnosed 1991-2000, SMR 1.06 (0.85-1.33) or 2001-2011, SMR 0.87 (0.61-1.24). In contrast, non- controlled patients at the latest follow up from both decades had elevated SMR, 1.90 (1.33-2.72) and 1.98 (1.24-3.14), respectively. Conclusions: The proportion of patients with biochemical control increased over time. Patients with biochemically controlled acromegaly have normal life expectancy while non-controlled patients still have increased mortality. The high rate of macroadenomas and unchanged age at diagnosis illustrates the need for improvements in the management of patients with acromegaly.

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