- Types of water pollution
- General description of the filter system
- First stage filters
- Cleaning to technical condition
- Drinking water preparation
Both in the central highways and in local sources, the water quality often leaves much to be desired. However, the situation is not hopeless; in a private house, modern filtration systems will help to purify water from impurities and make it drinkable, which will be discussed in this review..
Types of water pollution
Fresh water pollution can be the result of a wide range of factors: from natural pollution of water bodies to poor technical condition of treatment facilities and pipelines. If we are talking about a well or a well, then the main reason for the appearance of impurities in the water is the low quality of groundwater. Various filter systems help to cope only with a certain type of contamination, the list of which differs for tap water and well water.
In centralized water supply systems, water passes through a complex of treatment facilities. They remove the bulk of mechanical impurities, which are rich in surface water sources, and pre-disinfection is also performed. Despite the presence of treatment complexes in the water supply chain, the quality of water at the points of draw-off is far from ideal: it contains microscopic sand and rust, lime, magnesium and calcium salts, dissolved iron and manganese. Biological contamination in tap water is almost completely absent, with the exception of accidents at water treatment facilities.
But water from a well or well is quite capable of being a biological hazard. Microorganisms enter the well water from the upper aquifer when the water-resistant layer is disturbed or if the well does not have protection against leaks from the upper aquifer. In the wells, the water is also non-sterile: microorganisms live in the deep layers of the soil, in the course of their vital activity the liquid is saturated with hydrogen sulfide and other waste products. Plus, both well water and well water are characterized by increased hardness and content of mechanical impurities.
General description of the filter system
Regardless of the type of filters used, any water purification system for a private house consists of three stages. The filter resource is limited, so it makes sense to connect consumers separately at different stages of cleaning.
The first stage includes coarse filters that remove dirt particles from the water with a size of 0.15–0.5 mm. Mud filters have practically no effect on the final water quality; their main function is to protect pipelines and plumbing fixtures. Place of installation – as close as possible to the water source or the point of tapping into the main, but provided that the filter is accessible for service.
At the second stage, filters for fine mechanical cleaning and removal of hardness salts are installed. The function of the second stage is to make the water safe for plumbing equipment: faucets, showers, household appliances and water heaters. Also, fine cleaning and softening of water can reduce the consumption of detergents and electricity for heating. The set of second stage filters is installed in an equipped technical room, where low humidity and positive temperature are maintained throughout the year.
The third stage of purification is the preparation of drinking water – disinfection and neutralization of active chemical impurities. The presence of pre-filtration gives an advantage: the third-stage filters are compact enough to be placed under the kitchen sink, where mainly drinking water is taken. In addition, water of sufficiently high quality enters the final stage of purification, which increases the service life of the filters.
First stage filters
There are two options for the first stage cleaning device:
- When connected to a central water supply, a coarse mesh filter is installed in front of the water meter, but it cannot be considered as a full-fledged element of the first stage. The drain plug of the filter is sealed; moreover, the mesh size is usually from 1 mm. Therefore, immediately after the metering device, it is necessary to install a mesh or disc filter with a flushing system.
- When taking water from a well or well, a coarse cleaning element is installed immediately at the outlet of the supply pipe from the ground or directly in front of the surface pump. Since there is much more mud in well water, and the installation of filtration directly at the source is difficult, the first stage is divided into two elements: a filter up to 500 microns at the pump outlet and 100-200 microns at the inlet of the distribution unit.
The best option for a coarse filter would be Honeywell FF06 or more budgetary AZUD DF. If access to the filter installation site is difficult, you can pay attention to Erie Softena filters, which are washed in automatic mode, or the Honeywell Z11S drive attachment. Immediately after the coarse filter, it is recommended to install a tee outlet through which water is taken for irrigation or car washing, as well as for other consumers equipped with their own filtration system, for example, a swimming pool.
Cleaning to technical condition
At the second stage, filter systems are used, which are a sequential bundle of flow-through flasks with various cartridges inside. For fine mechanical cleaning, cascade cartridge filters with a capacity of 30–40 l / min are recommended. Depending on the quality of the water, the cascade can include from one to three stages with different cell sizes. An acceptable level of filtration is ensured when a filter with a 20 µm polyethylene cartridge is used at the last stage. If the content of mechanical impurities in the water is increased, the service life of the filter is greatly reduced, which can be leveled by installing one or two flasks with cartridges of 50 and 70 microns in front of it. In this case, it is not necessary to use ready-made cascade assemblies: the flasks are easily interconnected with collapsible brass fittings.
After mechanical cleaning, the chemical composition of the water is normalized. To select the right set of filters, you must first make a laboratory analysis of a water sample from a well or a water supply system. There are no universal solutions, however, as a rule, a bundle of a softening filter with a salt or ion exchange cartridge and an iron removal filter is used. In systems powered by a well or well, a PH correction filter can be installed if necessary..
The second stage of cleaning is the main one, after which the main branches of the water supply are connected. Water of this quality is optimal for supplying household appliances, a bathroom and filling the heating system.
Drinking water preparation
The final stage of purification is the preparation of drinking water, which requires disinfection and complete chemical neutralization. The first task is handled by three types of filters – ionizing, ultraviolet and reverse osmosis. The first two varieties are not particularly common due to their high cost and limited resource; as a rule, they are used in installations operating in non-stop mode. Reverse osmosis is the main method for preparing drinking water with a deep degree of purification from almost any impurities.
As a rule, reverse osmosis membranes appear as part of complex water treatment systems, but there are elements of preliminary treatment in the domestic water supply network. Therefore, at the point of drinking water intake, it is enough to install only a membrane and a storage tank, as well as a flushing automation. Please note that the membrane should be selected according to the nominal operating pressure of the system, if it is not high enough – install a pump for reverse osmosis systems.