Recycling of sludge from drinking water treatment as ceramic material for the manufacture of tiles

Abstract

Currently, the main destination for sludge from Drinking Water Treatment Plants (DWTP) is its disposal in sanitary landfills. However, its chemical composition and physical properties make it suitable for use as a building material. In this work, the use of spray-dried DWTP sludge on the manufacture of cladding ceramic material for the production of tiles as an alternative to the final disposal of sludge is analysed. The work is based on an experimental study carried out on a laboratory scale. Clay and spray-dried DWTP sludge (average humidity of 3 wt.%) were mixed with different percentages of sludge (from 0 to 70 wt.%) to form a slurry to be extruded. Specimens were then fired up to 980 ºC. Chemical and mineralogical composition of raw materials was analysed. Technical properties of the ceramic samples were determined. The results obtained showed that the DWTP sludge became a powder with low organic content and a high-micronised calcareous content (14.4 wt.% calcium oxide). The ceramic samples had a high open porosity, which increases with the increase in sludge addition percentage. They also had a high dilatometric coefficient. Taking into account these two properties, a possible application of this material would be the manufacture of glazed tiles. The resulting ceramic material does not pose any environmental problem, far surpassing the NEN-7345 leaching test and accelerated degassing tests (outgassing PSS-01-702 and offgassing PSS-01-729 standards of the European Space Agency).

Feasibility of Using Calcined Water Treatment Sludge in Rendering Mortars: A Technical and Sustainable Approach

“…The calcination process produces a material with higher inner voids, presented consequently as a lower specific gravity than sand [42], as can be seen in Table 2, leading to the decrease of this property with the increase of WTS content. According to Cremades et al [43], after burning samples in higher temperatures-between 550 • C and 800 • C-the carbonates release the CO 2 during the calcination process, leading to a considerable weight loss. So, with the increase of replacement level, the amount of CO 2 released is significant, decreasing the apparent specific gravity.…”

Development of Coloured Stoneware Bodies through the Incorporation of Industrial Cr/Ni Electroplating Sludge

“…Therefore, the addition of industrial wastes in the ceramic sector has been widely studied [8][9][10][11][12]. In structural and vitrified ceramic products, a wide variety of waste products/secondary raw materials have been studied, such as municipal waste [13], waste from water treatment [14,15], galvanization sludge [16,17], aluminium sludge waste [18,19], glass waste [20,21], fine steel sludge [22] and red mud [23,24]. In more detail, the possible use of municipal sewage sludge in the production of ceramic floor tiles was studied [11].…”

Structural Ceramics Modified by Water Treatment Plant Sludge

“…The use of WTP sludge in building materials could exclude expensive and energy-intensive stages of sludge utilization. WTP sludge can be used in structural ceramic production [ 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 ]. The volume of sludge to the volume of WTP treated water varies from 0.1% to 1%, and in some cases, can reach 5% [ 13 ].…”