Particle size distribution As noted above, TSS is a lumped parameter. In an effort to understand more nature of the particles that omprise the Tss in wastewater, measurement of particle size is undertaken and lysis of the distribution of particle sizes is conducted Information on particle size is of importance in assessing the effectiveness of treatment processes(e.g. secondary sedimentation, effluent filtration and effluent disinfection) Because the effectiveness of both chlorine and disinfection is dependent on particle size, the determination of particle size has become more important, especially with the move toward greater effluent reuse Information on the size of the biodegradable organic particles is significant from a treatment standpoint, as the biological conversion rate of these particles is dependent on size. The methods can be divided into two general categories: (I)methods based on observation and measurement and (2)methods based separation analysis techniques. The methods used most commonly to study and quantify the paticles in wastewater are: (1)serial filtration, (2)electronic particle counting, and microscopic observation(See Tab ab 2-4 Analytical techniques application to particle size analysis of wastewater contaminants Typical size range, um Observation and measurement Microscopy 0.2->100 Transmisson electron 0.2-100 Scanning electron 0.002-50 Image analysis 0.2->10 Particle counters Conductivity difference Equivalent light scattering 0.005->100 0.2->100 Centrifugation 0.08->100 Field flow fractionation 0.09->100 Gel filtration chromatography <0.000l->100 Sedimentation 0.05->100 0.0001-1 Pore size Serial Filtration. In the serial filtration method, a tewater sample is passed sequentially through series of membrane filters(see Fig 2-3)with k circular openings of known diameter(typically 12, 8, 5, 3, 1. and 0. I um), and the amount of solids interesting to note is the amount of colloidal material found between 0. I and 1.0 um. If a 0. I-Hm filter had (略) instead of a filter with a nominal pore size equal to or greater than 1.0 um(2.0 ugm as specified in Standard Methods for the TSS test), more than 20 g/L of additional tss would have been measured Fig. 2-3 Definition sketch for the determination of the particle size distribution using serial filtration with membrane filters Ithough some information is gained on the size and distribution of the particles in the wastewater sample little information is gained on the nature of the individual particles. This method is useful in assessing the effectiveness of treatment methods(e. g, microfiltration) for the removal of residual TSS 2-62-6 Particle Size Distribution As noted above, TSS is a lumped parameter. In an effort to understand more nature of the particles that comprise the TSS in wastewater, measurement of particle size is undertaken and an analysis of the distribution of particle sizes is conducted. Information on particle size is of importance in assessing the effectiveness of treatment processes (e.g., secondary sedimentation, effluent filtration and effluent disinfection). Because the effectiveness of both chlorine and disinfection is dependent on particle size, the determination of particle size has become more important, especially with the move toward greater effluent reuse. Information on the size of the biodegradable organic particles is significant from a treatment standpoint, as the biological conversion rate of these particles is dependent on size. The methods can be divided into two general categories: (1)methods based on observation and measurement and (2) methods based on separation analysis techniques. The methods used most commonly to study and quantify the paticles in wastewater are: (1) serial filtration, (2) electronic particle counting, and microscopic observation(See Tab 2-4). Tab 2-4 Analytical techniques application to particle size analysis of wastewater contaminants Technique Typical size range,μm Observation and measurement Microscopy Light Transmissoin electron Scanning electron Image analysis Particle counters Conductivity difference Equivalent light scattering Light blockage 0.2- >100 0.2- 100 0.002- 50 0.2- >100 0.2- >100 0.005- >100 0.2- >100 Separation and analysis Centrifugation Field flow fractionation Gel filtration chromatography Sedimentation Membrane filtration 0.08- >100 0.09->100 <0.0001- >100 0.05- >100 0.0001-1 Serial Filtration. In the serial filtration method, a wastewater sample is passed sequentially through a series of membrane filters (see Fig. 2-3) with circular openings of known diameter (typically 12, 8, 5, 3, 1. and 0. l μm), and the amount of solids retained in each filter is measured. What is interesting to note is the amount of colloidal material found between 0.1 and 1.0 μm. If a 0. l-μm filter had been used to determine TSS for the treated effluent instead of a filter with a nominal pore size equal to or greater than 1.0 μm (2.0 μgm as specified in Standard Methods for the TSS test), more than 20 mg/L of additional TSS would have been measured. Fig. 2-3 Definition sketch for the determination of the particle size distribution using serial filtration with membrane filters Although some information is gained on the size and distribution of the particles in the wastewater sample, little information is gained on the nature of the individual particles. This method is useful in assessing the effectiveness of treatment methods (e.g., microfiltration) for the removal of residual TSS