Express-method of determining the water-yielding capacity of natural water sludge in modern dewatering technologies

Abstract

Water treatment of surface sources for the purposes of public water service provision is impossible without waste build-up – sludge of water treatment plants. This kind of waste poses a considerable threat to the environment as it represents a complex organomineral structure with a high concentration of chemical reagents used for source water clarification and decolourization. In the present day, it is still international practice to discharge wastewater into surface water objects or onto the land surface, which causes severe damage to the natural environment. A tightening of environmental regulations encourages housing and utility services sector to undertake measures related to waste processing (waste dewatering). To implement these purposes mechanical machines (centrifuges, decanting tanks, filter presses, vacuum filters) are widely applied. An initial sludge quality, more particularly a filterability indicator – specific resistance to filtration – is a critical factor for the successful functioning of these machines. The higher the specific resistance to filtration, the worse the sludge gives away moisture, the more reagents and (or) mineral additives should be used before sending sludge for dewatering. Determining indicator of specific resistance to filtration using standard methods is quite a long process requiring the use of laboratory equipment. In this article, the author proposes an express-method enabling to determine within a short time span the water-yielding capacity of sludge based on the capillary suction speed of filtrate, standing out from its components. This method allows simplifying the start-up and commissioning of the modern sludge dewatering equipment as well as operation on the whole.