SU1142454A1 - Method of purification of waste water difficult-to filter - Google Patents

Abstract

A METHOD FOR CLEANING HARDLY SECTIONAL WATER TREATMENT, including reagent treatment and subsequent separation on filter presses, characterized in that, in order to improve the filtration performance and economic efficiency of the process, before the separation, the hydroelectric power plants are suspended in the waste water by matching the hydroelectric plants with thermal power plants in accordance with the distribution of the thermal power plants. up to 1: 5 on the solid phase ..

Description

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K9

4 SL

4ik The invention relates to the mechanical treatment of wastewater, mainly the purge water of water treatment plants of thermal power plants operating on solid fuels. A known method of cleaning the purge water of thermal power plants, consisting in their preliminary thickening followed by dewatering of the condensed sludge on filter presses. The clarified water is returned to the water treatment plant, and the filtered precipitate is transported to the slurry dump ij. The disadvantage of this method is that the thickened suspension of the purge water belongs to the difficult to be filtered, since the solid phase floccules formed in the clarifiers have low strength, are short-lived and easily deformed, which causes a low filtration rate. In this case, sticky sediment is formed, poorly separating from the filtering fabric. The closest to the invention in its technical essence and the achieved result is a method of filtering difficult to filter suspension of mine water, in which lime is suspended in the initial suspension {2j. An increase in the filtration rate caused by the coagulating effect of active calcium dioxide and the appearance of formed by the suspension of a significant amount of relatively large and durable particles of the solid phase (missing, mechanical impurities, etc.). However, the known method is characterized by insufficient filtration capacity, as well as a considerable consumption of technical lime (5-30% of the suspended suspension content) required to ensure the effectiveness of the known dewatering method, construction and operation of the lime reagent, which is associated with with significant capital and operating costs. The purpose of the invention is to increase the filtration performance and the process economy. The goal is achieved by the fact that, according to the method of purification of difficult-to-treat wastewater, including their preliminary reagent treatment and subsequent separation on filter presses, before the separation of wastewater from thermal power plants in a wastewater ratio in the ratio of 1: 1 to 1: 5 . The characteristic properties of the solid phase of the hydraulic ash discharge determine, during filtering, the resulting combined suspension of highly porous incompressible sediments, whose hydraulic resistance is significantly lower than the resistance of sediments formed during the filtration of difficult-to-filtered wastewater. Wastewater drains are introduced into the difficult to filter wastewater in such an amount that 1-5 kg of solid phase wastewater ash is removed per 1 kg of solid wastewater phase. After thorough mixing, the resulting suspension is fed to filtration. This treatment provides a significantly higher filtration rate than when filtering the untreated suspension. The resulting sediments easily lag behind the filter septum, have low humidity, transportability. Example. The purge waters of TPPs from clarifiers of the water treatment plant after treatment with sulfuric acid iron and lime milk in the amount of 0.4 mEq / l and meq / l of source water are used for cleaning. The concentration of the solid phase in the wastewater after clarification is 3-10 g / l, after condensation - 50 g / l. Suspensions of hydropower plants at power plants are obtained by flushing the products of coal combustion from the grate grids of furnaces. The solid phase concentration is 50 g / l. Filtration studies are carried out on a laboratory filtration apparatus with a surface of 0.01 m under a pressure of 0.4 MPa. As a filtering fabric, lavsan TLF-300-2 fabric is used. The filtration efficiency is estimated as the value of the specific productivity, which is defined as the volume of the suspension, filtered through a unit of surface per unit of belt. The test results are shown in table.

50

50

50

50

2t1

1.5

50

50

1: 1

10 Tissue residue is not far behind.

0.37 Precipitate badly behind the filter septum

6.8 The precipitate is poorly separated from the tissue

2.85 The precipitate is easily separated from the fabric.

Claims (1)

I METHOD FOR CLEANING DIFFICULTY WASTE WATER WATERS, including reagent treatment and subsequent separation on filter presses, characterized in that, in order to increase the filtration performance and process efficiency, a suspension of hydroelectric removal of thermal power plants is introduced into the wastewater before their separation in a ratio of 1: 1 to 1 : 5 solid phase.