SU865855A1 - Method of perifying washing water of water-pipe stations - Google Patents

Description

(54) METHOD FOR CLEANING WATER WATER WATER

one

The invention relates to methods for cleaning wash water and may find application in the field of drinking water supply.

A known method of purification of wash water, including sedimentation and dehydration of the precipitate formed by filtration. Vacuum filters, sheet filters, or filter presses 1 and 21 can be used to dewater the precipitate by filtration.

The disadvantages of this method

are: 1

1. The unsatisfactory effect of water clarification when settling 1 and the need to increase as a result of the residence time of water in the septic tanks, 4TCV significantly increases their size.

2. Low productivity of filtering devices due to high resistivity of dewatering sediments.

These deficiencies are the main reason preventing the widespread introduction of sludge dewatering into the drinking water supply technology.

There is also known a method for purifying wash water, which includes beside the sedimentation.

By conditioning and filtering, the conditioning of the precipitate formed with the help of reagents, including mineral coagulants (iron salts, aluminum and lime) and organic flocculants (for example, PAA).

When the precipitate is conditioned with reagents, the process of aggregation of finely divided particles coagulates.

10 and colloidal particles, the formation of large flakes with a rupture of the solvation shells and a change in the forms of the bond of moisture, which leads to a change in the structure of the sediment and to an improvement in its sedative properties 3.

However, when implementing this method, the resistivity of precipitation remains very high, which does not allow efficient use of 20 for their dehydration, vacuum filters, sheet filters, etc.

In addition, the disadvantages of the method include the corrosivity of mineral coagulants, their high cost, and the complexity of transportation and preparation.

The closest technical solution is a method for cleaning wash water, waterworks, 30 which includes sedimentation and dewatering of sludge by filtration with the introduction of waste products, in particular, EOLA from boiler plants or from incineration of precipitates, before filtering.

This method allows to intensify the process of sludge dewatering on filters due to the fact that the introduction of ash creates a rigid skeleton on the filter septum, which leads to an increase in filtering speed and improves the conditions for separating the dehydrated sludge from the filter fabric.

The disadvantages of the method are: the unsatisfactory effect of water clarification during settling, the difficulty of mixing the compacted sludge with ash to form a homogeneous mass, a significant consumption of ash.

The purpose of the invention is to intensify the process by increasing the degree of clarification of water during sedimentation and improving the water returning properties of the sediment.

The goal is achieved by the introduction of ash before settling.

Preferably, the ash is introduced in an amount of 0.1-1.0 wt.% Of the water to be purified.

Example 1. Wash water from contact clarifiers of a waterworks, obtained by taking equal portions of water every 30 seconds during the entire flush, is poured into one vessel and stirred for averaging.

The composition of the washing water after averaging is characterized by

The following indicators: temperature: 6.1 ° C; content of substances to be weighed (by weight) 328 mg / l; oxidation 104 mg / l pH 6.2; bicarbonate alkalinity of 0.25 mEq / l; color 7 degrees.

The test wash water was poured into 7 pillars of the cylinder to remove the sedimentation curves upon settling. In all cylinders, except for the control one, shale ash is added, which is dust trapped from flue gases in multicyclones of a state district power station. The amount of injected ash varies from 0.05 to 1.5 wt.% Of the amount of wash water. After the introduction of the ash, the water is stirred for 120 seconds and settled in the cylinders for 15 minutes to remove the precipitation curves. Then the clarified water is drained and the precipitate is decanted by vacuum filtration through an ashless paper filter (with a blue stripe) on a Büchner funnel.

The magnitude of the vacuum over all experiments was kept constant and equal to 250 mm Hg.

The criteria for the effectiveness of the experiments are: the content of suspended substances in clarified water, the degree of clarification and the percentage rate of precipitation suspended before settling; as well as the resistivity of the precipitate, its moisture content after evacuation and the duration of filtration of 100 g of sediment during the dewatering of the precipitate by vacuum filtration. The results are shown in the table.

Note When introducing ash into the sediment immediately before filtering in an amount of 15 wt.% Ash based on the weight of the wet sediment, the resistivity of the sediment is 0.11-10 cm / g, and the moisture content of the dewatered sediment is 31.2%.

Claims (2)

Claim 1. The method of purification of wash water of water stations, including from -. melting and dehydration of the precipitate formed by filtration with the introduction of conditioning 30 ash substances, characterized in that, in order to intensify the process by increasing the degree of clarification of water during sedimentation and improving the water discharge properties 35 sediment, ash is introduced before settling. 2. The method according to π. 1, they are distinguished by the fact that ash is introduced in an amount of 0.1-1.0 wt.% From • rinsing 40 noy water.