Particle size distribution and wastewater filter performance

Tertiary filtration can be proposed in small wastewater treatment plants with impact on protected water bodies. Rotating disk filters may be adopted, in respect to conventional sand filters, when low availability of space and low investment costs are the prevailing conditions. The overall objective of this research was to evaluate the filtration efficiency of rotating disk filters; to compare effectiveness with traditional sand filters; to analyse thoroughly the importance of particle size distribution in wastewater tertiary filtration. In the experimental activity, conventional wastewater quality parameters were investigated and particle size distribution (PSD) was characterized to discuss the filter effectiveness. The effect of design and operation parameters of tertiary filters were discussed related to particle removal curves derived from particles counts. Analysis of particle size distribution can be very useful to help comprehension of filtration processes, design of filtration treatments and to decide the best measures to improve filter performance.

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HEPA Filter Performance Under Adverse Conditions

11th International Conference on Environmental Remediation and Radioactive Waste Management, Parts A and B ◽

10.1115/icem2007-7074 ◽

2007 ◽

Author(s):

Michael Parsons ◽

Kristina Hogancamp ◽

Steven Alderman ◽

Charles Waggoner

Keyword(s):

Particle Size ◽

Particle Size Distribution ◽

Size Distribution ◽

High Efficiency ◽

Department Of Energy ◽

Emission Rates ◽

Filter Function ◽

Filter Performance ◽

The Media ◽

Effect Of Particle Size

This study involved challenging nuclear grade high-efficiency particulate air (HEPA) filters under a variety of conditions that can arise in Department of Energy (DOE) applications such as: low or high RH, controlled and uncontrolled challenge, and filters with physically damaged media or seals (i.e., leaks). Reported findings correlate filter function as measured by traditional differential pressure techniques in comparison with simultaneous instrumental determination of up and down stream PM concentrations. Additionally, emission rates and failure signatures will be discussed for filters that have either failed or exceeded their usable lifetime. Significant findings from this effort include the use of thermocouples up and down stream of the filter housing to detect the presence of moisture. Also demonstrated in the moisture challenge series of tests is the effect of repeated wetting of the filter. This produces a phenomenon referred to as transient failure before the tensile strength of the media weakens to the point of physical failure. An evaluation of the effect of particle size distribution of the challenge aerosol on loading capacity of filters is also included. Results for soot and two size distributions of KCl are reported. Loading capacities for filters ranged from approximately 70 g of soot to nearly 900 g for the larger particle size distribution of KCl.

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Particle size distribution and wastewater filter performance

Water Science & Technology ◽

10.2166/wst.1997.0123 ◽

1997 ◽

Vol 36 (4) ◽

pp. 217-224 ◽

Cited By ~ 7

Author(s):

Iris Kaminski ◽

Nicolae Vescan ◽

Avner Adin

Keyword(s):

Particle Size ◽

Particle Size Distribution ◽

Size Distribution ◽

Power Law ◽

Filter Performance ◽

Natural Lakes ◽

Size Groups ◽

Filter Operation ◽

Power Law Function ◽

And Function

Particle size distribution (PSD) allows more accurate simulations of filtration models and better understanding of filter performance. PSD in municipal activated sludge effluent filtration is determined, varying filtration rate, grain size, flocculant type and dosage and function parameters are examined in this work. Results show, that removal efficiency varies for different size groups: small particles in the range of 5-10 μm in initialization stage, with no chemical aids, are poorly removed. Higher rate filters were more sensitive to the particle size than lower rate filters. Filtration with chemical aids is more sensitive to filtration conditions than filtration with no chemical additions. Particle size distribution in filtrate generally fits power law function behavior better than in raw effluent. The treatment smoothens the function somewhat. In a similar manner to the effect of settling in tanks or in natural lakes. Degree of correlation to power law function may indicate the mode of filter operation: high - working stage, low - breakthrough stage. β may also reflect on filters performance: high values - initial filtration stages. Decrease in β values - cycle progress towards breakthrough. Low β values, with low PSD correlation to power law function, may indicate low filtration efficiency or breakthrough.

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