Water treatment plant (WTP) sludge is actively used in building materials production. The object of this research was modifying additives for ceramic bricks from WTP aluminium-containing sludge. The research aim of this study was to determine the suitability of a million-plus population city’s WTP sludge as a burning-out additive in the production of structural ceramics and to establish the optimal conditions for obtaining products with the best characteristics. The raw water belongs to water belongs to the hydrocarbonate class, the calcium group, and it is of low turbidity (1.5–40 mg/L kaolin). Sludge, sourced from WTP sedimentation tanks, was dewatered by adding lime or by using the freezing-thawing method. The spray-dried WTP sludge is introduced into the clay in amounts of 5% to 20% by weight. The addition of 20% reduces the sensitivity of the clay to drying, reduces the density of ceramic by 20% and simultaneously increases its compressive strength from 7.0 to 10.2 MPa. The use of WTP sludge as a modifying additive, pretreated by the freezing-thawing method, makes it possible to obtain ceramic bricks with improved properties. The results can be used for WTP sludge containing aluminium obtained by treating water of medium turbidity and medium colour.

The water yielding capacity of the sludge in water-supply network treatment facilities is determined by the water quality in a water source and its treatment technology. The paper studies the sludge of water-supply network treatment facilities formed in the conditions of low turbidity and average water colour index in the water source. Such sludge has a low water yielding capacity and is subject to conditioning. The paper shows the influence of seasonal variations of turbidity, water colour index and temperature of the feed water on the specific sludge filtration resistance. It considers the specific features of sludge formation in different settling basins influencing its water yielding capacity. It is shown that the washwater return performed at one of the blocks of the facilities increases the feed water turbidity and leads to the formation of the sludge easily susceptible to conditioning. The paper studies the following methods of the reagent sludge treatment: polyacrylamide-based flocculant treatment, joint treatment with flocculant and vermiculite filler, lime treatment. The use of vermiculite allows to reduce the required flocculant dose. The author determines optimum doses of reagents allowing to direct the sludge for further mechanical dewatering after conditioning. It is shown that, when the sludge is processed with lime, the filtrate formed at dewatering can be reused as an alkalifying agent, which will allow one to cut the costs for the acquisition of reagents.

The coagulation of low-water with reagent purification is difficult because of the low concentration of suspended solids. The increased consumption of coagulant in this case leads to an increase in the content of residual aluminum or iron in water leaving the treatment facilities of the water supply. Clapping can be intensified by adding mineral opacifiers to the water, the particles of which play the role of additional centers of flocculation, weigh the flakes and increase the degree of water purification due to sorption processes occurring on their surface. In the paper, the efficiency of using opoka for the turbidity of slightly contaminated surface waters is investigated. The composition of this rock contains a significant amount of silicon dioxide, which determines the sorption properties of this material. The study was carried out using the jar-test experiment, using the water of the Shershni reservoir on the Miass River. It was found that the use of the opoka is expedient with a two-stage water purification scheme "sedimentation-filtration". The opoka was dosed in the form of an aqueous suspension prior to the administration of the coagulant. The reduction of the residual aluminum content in the filtrate is more effective by 40% compared to the experiment without the opoka. It is noted that in the conditions of low temperatures the effect of opoka is more pronounced.