Particle Shapes in the Drinking Water Filtration Process

Abstract

Depth filtration is still one of the most important water treatment processes. It remains difficult to model mathematically because of the complexity of the process and the impact of numerous suspension parameters. The shape of the grains and suspension particles or flocs are among these parameters. The results of theoretical calculations suggest their visible impact on filtration. The shape of the media grain is relatively easy to measure. The shapes of the flocs or suspension particles, which are commonly not perfectly spherical, are much more difficult to predict. However, a few apparatuses developed lasting recent years make this possible. The FPIA 3000, manufactured by Malvern Instruments, uses flow particle image analysis method to measure 26 shape parameters of the suspension particles. Experimental measurement of suspension particle shape after flocculation and after depth filtration has allowed us to answer the question regarding the possible application of this measuring technique in water filtration technology. The experiments have also provided us with detailed information about the shape of flocs and suspension particles in filtered water. High number of particles characterized by circularity lower than 0.8 was detected in flocculated water inflowing to the filter. The particles remained in the outflow was characterized by visibly higher circularity than the particles inflowing to the filter. The results revealed much better removal of the particles characterized by lower circularity during filtration, whereas relation between convexity of the particles and their removal efficiency was not so evident.

Designing Iron‐Amended Biosand Filters for Decentralized Safe Drinking Water Provision

“…Alternative BSF designs for better efficiency in aqueous contaminant removal have been tested 2, 4, 45, 46, 58, 59. Tested design parameters include: (i) sand type, sand size and sand depth 31, 32, 60, (ii) maturation time or time to formation of the Shmutzdecke , (iii) elevation head, (iv) standing water depth, (v) filter pause time or daily water throughput, as well as (vi) amendment of conventional BSF with reactive layers containing metallic iron (Fe 0 ). The present communication is focused on the design of Fe 0 ‐amended BSF.…”

“…Therefore, all tested materials should be characterized for their intrinsic chemical reactivity 93, 94, 97 and their sphericity in order to enable results comparability. Next to the intrinsic reactivity, used devices should be characterized by 32, 60: (i) their dimensions, e.g. internal diameter and depth of reactive layers for cylindrical columns, (ii) the particle size and the surface state of used materials (e.g.…”

Monitoring particle size distribution for water treatment processes

“…The shape, porosity, roughness, chemical composition and color of suspended particles changed in the processes [11]. Unfortunately, most of the light scattering theories are valid only for transparent and even spherical particles.…”

Functional Safety Concept to Support Hazard Assessment and Risk Management in Water-Supply Systems

“…The main goal is the safeguarding of the consumer from the incidental contamination of the water source [35]. Otherwise, raw-water tank operations require an effective protection-and-warning station equipped with an automatic analyser and a continuous transmission of results to the dispatcher of the WTP.…”