Wastewater treatment systems for a private house

From this article, you will learn about the most common ways to equip a sewage treatment system for a private house, about the pros and cons, features of operation, as well as the cost of each of the options for these systems.

Proper arrangement of the drainage system can be considered one of the most difficult and responsible tasks in the design of an individual house. The most common ways of arranging a local sewage system are:

• storage pits
• septic tanks of various types
• biological treatment systems

All wastewater treatment systems work with the participation of microorganisms, which, in the course of their life, absorb pollution, which is an excellent nutrient medium for them. The quantity and species composition of these bacteria determine the type and quality of the final treatment. The organization of the process is fundamentally possible only in three ways:

1. With the use of putrefactive bacteria, without creating additional favorable conditions for them. Effluent treatment is minimal. This type is typical for various wastewater storage tanks.
2. The use of anaerobic microorganisms living in an oxygen-free environment. The degree of wastewater treatment is on average about 50%. This option is used in the operation of various types of septic tanks. Advanced biofeeding devices involve the intermittent supply of artificially grown microorganisms.
3. The use of aerobic bacteria that need a constant supply of oxygen. The process of wastewater treatment proceeds similarly to the natural decomposition of waste, but much faster. The output is industrial water purified by 98%. It is used in biological treatment systems with aerotanks.

Thus, it is possible to equip a local sewage system in various ways and at different costs, but the effect will not be the same. The choice of the system remains with the owner of the home, and in order to facilitate it, we will consider the main ways of arranging an autonomous sewage system.

Cesspools

Devices are the simplest drives designed to collect sewage. Effluent enters the tank through a pipeline, which must be laid below the freezing level of the soil or additionally insulated. As the pit fills up, it is cleaned out with a cesspool truck. The building must be airtight, this is a guarantee of its safety. Variants of pits without a bottom or with a filter layer of sand and gravel arranged at the bottom poison the soil and, accordingly, groundwater, which makes them a serious source of pollution.

An autonomous sewage system with a cesspool has certain advantages:

1. Extreme simplicity of design.
2. Cheap manufacturing and installation. If an industrial production capacity is purchased, the costs will be slightly higher.
3. The device does not require maintenance, except for pumping out. It does not depend on the supply of electricity and does not require the arrangement of additional treatment zones, such as filtration wells or fields.

There are also disadvantages of the system:

1. The need for regular pumping of sewage, which requires certain costs to pay for the services of sewers.
2. A fairly high probability of depressurization of the tank and the ingress of effluents into the soil and groundwater. This is especially true for metal structures that are prone to corrosion.
3. Bad smell.
4. The location on the site is limited by sanitary standards, while still taking into account the possibility of free access to the pumping facility.
5. The impossibility of arrangement in the case of a high level of groundwater.

There are many options for arranging cesspools. The simplest, but also the most expensive, is the purchase of a ready-made tank. Most often these are plastic containers of various shapes and volumes. They are not subject to corrosion and keep the tightness all term of operation. There are many types of such drives. These are "Tank", "Triton", "Leader", "Topas" in various modifications. The cost of devices starts from 9,000 rubles.

Many people prefer to equip cesspools with their own hands. Such structures are made of brick, concrete, cinder blocks or tires. Another common option is to use a finished metal container or make one to the desired size. In any case, when choosing a cesspool as an autonomous sewer, one should assess the intensity of its future pumping. Very often, clean-up costs are high and nullify the apparent benefit of arranging the cheapest option.

Septic tanks

A septic tank is a technologically connected system of tanks in which, with the participation of anaerobic bacteria, mechanical treatment of domestic wastewater occurs. Contaminated liquid flows from one container to another. In each of them, solid fractions settle, which are subsequently decomposed by bacteria. The accumulated sediment must be periodically removed from the system. Septic tanks clean drains up to a maximum of 60-70%. All solid insoluble contaminants remain inside the system, while light fractions continue to be present in the water. It needs to be further cleaned. For these purposes, special structures are used, the choice of which is determined by the type of soil.

Most often these are filtering fields. They are spray pipes placed in trenches made of a filter element with a thickness of at least 1 m, under which a drain is laid to drain clean water. Such fields should be equipped at a certain distance from sources of drinking water and fruit plants. In addition, the depth of their laying must be greater than the level of soil freezing, otherwise the system will not be able to work in the cold season. Once every five to seven years, it is necessary to dig out the structure, completely rinse or replace the filter layer. In any case, such fields are a very expensive and environmentally unsafe device.

The water purification system for a private house - with the help of a septic tank has undeniable advantages:

1. Complete energy independence.
2. Relative cheapness of arrangement and installation.

Its shortcomings include:

1. Low level of domestic wastewater treatment.
2. The need to equip an additional cleaning system such as filtration wells, fields, etc.
3. Regular, although not as frequent as for cesspools, pumping sludge from the system.

You can set up a septic tank yourself. For this, several containers are made, interconnected. They can be made of concrete, brick, tires. Eurocubes are also used for these purposes. Home-made systems will cost their owner less than industrial septic tanks. However, the latter are distinguished by high reliability and a variety of models, which allows you to choose the best option for specific conditions.

The main criteria for choosing a septic tank are:

1. The capacity or amount of effluent processed by the device. Measured in cube. m / day.
2. The quality of the container material.
3. The maximum value of a salvo discharge, that is, the volume of wastewater simultaneously entering the chamber of the device in cubic meters.
4. The degree of cleaning carried out by the facility.
5. Limiting value of short-term loads. For some models, it is permissible to exceed the passport loads for a short time, which must be indicated in the device documents.
6. Possibility of installation of a design in the conditions of a high level of ground waters.

As practice shows, it is best to purchase a septic tank in companies specializing in the sale and installation of devices. In this case, you can be sure of the correct selection and installation of the system, which will save you from problems and additional costs for correcting mistakes. In addition, it is necessary to familiarize yourself with the certificate, hygienic conclusion and guarantees. These documents must be present.

Comparative characteristics of the most common models are given in the table:

Stations of deep biological treatment

Deep biological wastewater treatment - can only be done with the help of aeration stations. These are devices that use the principle of natural biological purification, which is ubiquitous in nature. Mechanical cleaning, combined with the action of aerobic and anaerobic bacteria, makes it possible to obtain 98% purified technical water and sludge, which can be used as fertilizer.

The principle of operation of the systems is quite simple. Effluent enters the receiving chamber, where large sewage is crushed and the liquid is saturated with oxygen. The wastewater prepared in this way, after passing through the coarse filter, is directed to the biological treatment chamber with the help of an airlift. Biomass forms active suspended sludge, on the flakes of which cleaning processes take place. With the help of airlifts, the spent sludge is transferred to the activated sludge stabilizer.

The treated effluents are freed from the suspended particles dissolved in them and discharged into water bodies or onto the relief. In addition, such water can be used for technical needs, for example, for irrigation. On average, once a month, the spent sludge is pumped out of the device using a standard pump. It is an excellent source of biofuel and a high quality fertilizer.

The advantages of using such a system are obvious:

1. A high degree of wastewater treatment, reaching up to 99%, which allows you to freely discharge the received process water or use it for household needs.
2. The compact dimensions of the installations allow minimizing the work on arranging an autonomous sewage system.
3. Extreme ease of maintenance.
4. No unpleasant odors.
5. Ease of installation of the device, which does not require special equipment.
6. Possibility of installation in soils of any type.