RU2292416C1 - Method for collectiong, cleaning and discharging of filtrate at domestic and industrial waste proving ground - Google Patents

Abstract

FIELD: neutralization of solid domestic and industrial wastes, in particular, collection, cleaning and discharging of filtrate formed in proving ground layer.

SUBSTANCE: method involves constructing multilayer anti-filtering screen with drainage interlayer in proving ground base; collecting, cleaning and discharging filtrate; ensuring that screen upper layer be filtering and having predetermined permeability parameters allowing filtrate collected above screen filtering layer to be settled and subjected to anaerobic cleaning procedure; providing additional cleaning of filtrate in drainage interlayer; discharging filtrate through drains laid in drainage interlayer above lower water-resistance screen layer. Bentonite-based membranes are used for formation of screen upper layer. Additional cleaning of filtrate in drainage interlayer is carried out using anaerobic process or aerobic process including controlled supplying of air through drains.

EFFECT: reduced adverse effect upon environment due to decreased concentration of contaminants in sewage penetrated through upper screen filtering layer, and increased efficiency in discharging of penetrated sewage through screen drainage interlayer.

4 cl, 1 dwg

Description

The invention relates to the disposal of solid household and industrial waste, and in particular to methods for collecting, cleaning and discharging filtrates formed in the thickness of the landfill for solid household and industrial waste (TBPO).

A known method of protecting groundwater from the ingress of pollutants using an anti-filter screen, the permeable layer of which is made of porous glauconite material that absorbs some toxicants (Pat. No. 2226587, MKI E 02 B 3/16, publ. 05.27.2003).

However, the use of glauconite for the device of the filter layer of the anti-filter screen does not provide reliable and long-term treatment of wastewater and the protection of groundwater from pollution.

Closest to the technical nature of the present invention is a method of protecting groundwater from contamination by untreated sewage, where the anti-filter screen consists of clay soil with a drainage layer of permeable material and a drainage drainage that allows fluid to be filtered through the upper drainage layer (A.S. No. 310972, MKI E 02 3/16, publ. 08/09/1971, Bull. No. 24.).

The disadvantage of this method is that clay screens do not provide complete protection of groundwater from the emission of dissolved substances in the filtrate.

The technical result of the invention is to reduce the harmful effects on the environment by reducing the concentration of contaminants in the effluents filtered through the upper filter layer of the screen and effectively discharging filtered effluents through the drainage layer of the screen.

This is achieved by the fact that in the method of collecting, cleaning and discharging the filtrate at the solid domestic and industrial waste landfill, including constructing a multilayer screen with a drainage layer at the base of the landfill, collecting, cleaning and discharging the filtrate, the upper layer of the screen is filtered with specified permeability parameters, providing sedimentation and anaerobic purification of the filtrate collected above the filter layer of the screen, additional purification of the filtrate in the drainage layer and its removal through drains, we lay e interbed in the drain above the lower layer of water-resistant screen.

At the same time, membranes based on bentonite clays are used for the device of the upper layer of the screen, and the filtrate is additionally cleaned in the drainage layer using the anaerobic method or aerobic method with controlled air supply through the drains.

The essence of the method is illustrated in the drawing, which shows a diagram of the collection, treatment and removal of the filtrate at the landfill of solid household and industrial waste using a multi-layer screen of the landfill.

On the drawing there are designations: 1 - a waste layer that serves as a regulatory capacity, 2 - a filtrate level above the screen, 3 - a protective layer of the screen above the membrane, 4 - the upper filter layer of the screen, 5 - drainage layer, 6 - tubular drains, 7 - lower water-resistant layer of the screen, 8 - film coating over the water-resistant layer of the screen, 9 - direction of movement of wastewater in the thickness of the waste, 10 - surface of the filtrate in the drainage layer, 11 - direction of movement of the filtrate in the drainage layer.

Collection, treatment and disposal of effluents at the landfill is as follows.

The anti-filter screen at the base of the landfill is multilayer.

Sludges filtered through the waste thickness in direction 9 are collected at the bottom of the waste array 1, where a water-saturated zone is formed, which acts as a regulating capacity, thanks to the design of the landfill, which makes it possible to raise the filtrate level from 2 to 2.5 m above the upper filter layer of the screen .

The inflow of the filtrate to the multilayer screen is characterized by extreme unevenness due to seasonal fluctuations in hydrological parameters and the presence of freshly laid waste layers. When salvo water inflows during spring snowmelt or heavy rains, an increase in volume and an increase in the level of the saturated zone above the screen occur. Under the influence of increased pressures, the filtration costs through the multilayer screen also increase, then, as the inflow of the filtrate and the level of the saturated zone decrease, the filtration costs decrease.

The upper layer of the screen is made in the form of a membrane 4 having a given permeability - so that it passes the average annual filtrate layer at pressures of 2-2.5 m. For this purpose, for example, bentonite clay roll material is used to arrange the upper layer of the screen Bentomat AS50. To protect against mechanical damage, the membranes 4 arrange a soil protective layer of the screen 3.

The sewage filtered through membrane 4 has significantly reduced concentrations of contaminants compared to the original filtrate due to the following factors:

- dilution by atmospheric precipitation with an infiltrate, mainly in the spring when there is a plentiful supply of melt water from the surface;

- anaerobic cleaning with a long stay in the anaerobic saturated zone above the upper layer of the screen 4; the length of stay is on average 200-250 days, with a weak inflow of filtrate for more than a year;

- retention by the membrane of 4 suspended substances contained in the filtrate and bearing a significant proportion of contaminants;

- sorption of some contaminants by clay minerals of the membrane 4.

Below the filter layer of the screen (membrane) 4, a waterproof screen layer is arranged, for example, a clay layer 7 with a film coating 8, which prevents leakage of filtered effluents through the membrane into groundwater.

Between the filtering 4 and the water-resistant layers 7 of the screen there is a drainage layer 5 made, for example, of sand and gravel soils, with drains 6 located in it, for example, tubular, through which drains filtered through the membrane are discharged to a drainage collector and then to treatment facilities, for example, biological (BOS).

The drains filtered through the membrane 4 enter the drainage layer 5, along which they migrate in the direction 11 to the nearest drains 6. The average residence time of the drains in the drainage layer 5 is 50-60 days. With the passage of effluents through the drainage layer 5, they are additionally cleaned of contaminants.

Sewage treatment in the drainage layer 5 can be carried out in two ways:

a) according to the anaerobic cleaning scheme, without air access to the drainage.

The exothermic process of anaerobic decomposition of organics ensures the maintenance of a stable temperature regime in the lower layers of the waste layer (t = 25-30 ° C), which ensures high efficiency of anaerobic purification of the filtrate in the saturated zone above the membrane and in the drainage layer.

b) according to the aerobic treatment scheme with nitrification-denitrification of effluents with controlled air supply to the drainage layer through drains.

The application of the proposed method of collecting, cleaning and discharging the filtrate at the solid waste landfill allows you to abandon the creation of a large regulatory capacity (storage pond), to ensure effective pre-treatment of wastewater before treatment facilities (OS) and to exclude groundwater pollution by landfill wastes.

Claims (4)

1. A method of collecting, cleaning and discharging filtrate at a solid domestic and industrial waste landfill, including constructing a multilayer screen with a drainage layer at the base of the landfill, collecting, cleaning and discharging the filtrate, characterized in that the upper layer of the screen is filtered with specified permeability parameters, providing sedimentation and anaerobic purification of the filtrate collected above the filter layer of the screen, additional purification of the filtrate in the drainage layer and its removal through drains placed in drainage layer above the lower waterproof layer of the screen. 2. The method according to claim 1, characterized in that for the device of the upper layer of the screen using membranes based on bentonite clays. 3. The method according to claim 1, characterized in that the additional purification of the filtrate in the drainage layer is carried out by anaerobic method. 4. The method according to claim 1, characterized in that the additional purification of the filtrate in the drainage interlayer is carried out by the aerobic method with controlled air supply through the drains.