Table of Contents
Is sludge viscous?
Activated sludge is generally recognized as a kind of non-Newtonian fluid, i.e. apparent viscosities measured under different shear rates are different (Ron 2001).
What is sludge viscosity?
Viscosity is defined as the ratio of shear stress to shear rate. As the the viscosity of sludge is not constant and needs to be determined by its fluid-dynamic condition, ‘apparent viscosity ‘ was introduced 12, which could be calculated from the flow curves measured by rheomoters.
What is liquid sludge?
Sludge is a semi-solid slurry that can be produced from a range of industrial processes, from water treatment, wastewater treatment or on-site sanitation systems. In the activated sludge process for wastewater treatment, the terms “waste activated sludge” and “return activated sludge” are used.
Is sludge liquid or solid?
In the wastewater industry, sludge is a solid and liquid hybrid. It can be a semi-solid slurry, a solid from a wastewater treatment plant, or a settled slurry from drinking water treatment. Semi-solids such as sludge are generally treated as solid waste at treatment facilities.
What do you understand by sludge?
1 : mud, mire especially : a muddy deposit (as on a riverbed) : ooze. 2 : a muddy or slushy mass, deposit, or sediment: such as. a : precipitated solid matter produced by water and sewage treatment processes. b : muddy sediment in a steam boiler.
How do you reduce the viscosity of sludge?
Since the viscosity of the continuous phase is higher than the dispersed phase, the viscosity can be reduced by increasing the ratio of water to oil. Of course, the presence of emulsifier plays an important role in homogenization of the sludge and penetration of water molecules into the sludge texture.
How do you treat sludge?
Digestion. Many sludges are treated using a variety of digestion techniques, the purpose of which is to reduce the amount of organic matter and the number of disease-causing microorganisms present in the solids. The most common treatment options include anaerobic digestion, aerobic digestion, and composting.
MBR sludge viscosity. The non-Newtonian nature of sewage sludge means that its measured viscosity µs, referred to as ‘apparent viscosity’, varies with shear rate due to the shear-dependent deformation of the flocculant solids (Yang et al, 2009).
Why is sludge filterability and viscosity change with temperature?
High-SSVI sludges are often associated with filamentous micro organisms, which are widely known to generate a high resistance to sludge filtration due in part to the hydrophobic nature of the micro organisms. So, just how do sludge filterability and viscosity change with the key property of temperature?
Is there a relationship between water and sludge?
This is possibly the simplest, and the most ubiquitous, relationship to consider. The rheological properties of both water and sludge are widely understood.
Which is the best measure of sludge quality?
In practice, a rough-and-ready indication of bulk sludge quality is provided by (specific) sludge volume index ( (S)SVI), capillary suction time (CST) and time to filter (TTF).