The domestic waters are those that are used in the home or family dwelling site and then discarded as waste or waste. As waste they are called sewage, sewage or domestic sewage.
The use of domestic water includes its direct intake or as part of food and beverages, as well as its use in personal hygiene. In the same way, it is used in washing clothes, cleaning household goods and infrastructure..
On average, more than 150 L / inhabitant-day are consumed, although according to the World Health Organization 50 L / inhabitant-day of domestic water is required. It is used for personal bathing, washing utensils, cleaning floors, washing the car, watering the garden or diluting body waste.
Once used, it must be discarded and transformed into domestic wastewater, which carries a large amount of impurities. These domestic wastewaters are classified according to their origin as black water and gray water..
Sewage comes from toilet flushes and is made up of organic matter, especially feces, urine, and microorganisms. While gray water comes from personal hygiene, laundry and household hygiene.
Article index
Domestic waters originally consist of raw water from natural sources such as deep wells, rivers, or lakes. They are subjected to purification that includes filtering, disinfection and the addition of certain substances to adapt it to the standards established for human consumption..
Of the water consumed, around 70-80% of the water consumed in the home is transformed into domestic wastewater. They are classified into two types according to their origin, which are black water and gray water.
The former are those generated in the evacuation of human physiological waste (feces, urine), while the latter cover the rest of wastewater.
The largest volume of domestic water is used in the evacuation of human organic waste. On average 10,800 liters / person per year are spent on the toilet drain and the most efficient consume up to 6 liters while others use an average of 26 liters.
Another important source of domestic wastewater is personal hygiene operations, such as daily showering or washing, shaving, and hand washing. According to the World Health Organization, on average it is estimated that 95 liters / person of water is consumed in a 5-minute shower.
Doing laundry or washing clothes in a 7 kg capacity washing machine, consumes between 42 and 62 liters of water.
Scrubbing kitchen utensils generates a water consumption of between 50 and 100 liters per day, although if a dishwasher is used this consumption can be reduced to 10 or 18 liters per wash..
Although it is difficult to quantify maintaining the hygiene of floors, windows and other parts of the home, it also generates significant water consumption.
Washing the car with a hose causes an enormous consumption of water, close to 500 liters. Whereas if it is carried out in a car wash it can be reduced from 100 to 300 liters.
Watering plants also generates domestic wastewater, but in a garden on land it is absorbed by the soil. In the case of potted plants, the surplus can become wastewater that ends up in the drain.
As an inflow, domestic water is drinkable, previously subjected to filtering processes, the application of ozone, ultraviolet radiation or the addition of chlorine. Once used, domestic water is contaminated with a large amount of substances.
The composition of water for domestic consumption depends on both the source of the water and the previous treatment it receives. In general, water from underground sources have high mineral content, especially calcium.
Taking Spanish legislation as a reference, in drinking water there should be no presence of any type of microorganism. While in relation to chemical components present, certain levels are accepted depending on the case.
For example, water can contain up to 10 µg / l of arsenic or 2 mg / L of copper and be safe for consumption. In general, water for human consumption can contain traces of numerous chemical elements, including nitrates, heavy metals and even traces of pesticides..
Faeces are the main organic component of domestic wastewater and they contain 90% carbohydrates in addition to fatty acids, proteins and hydrocarbons. Human urine has urea as its main component, however, it decomposes quickly when discarded..
The toilet paper used, when it is flushed down the toilet, incorporates large amounts of cellulose and various chemicals. On the other hand, domestic drains also carry organic debris from food preparation.
These wastes incorporate plant and animal tissues and exudates into domestic wastewater. Washing floors and other parts of the house carries dust that incorporates remains of epidermal cells and hair.
Similarly, discarded domestic water carries traces of synthetic organic substances such as phenols, detergents, soaps and organic disinfectants..
The most abundant are coliforms, especially fecal coliforms, the most frequent being bacteria Escherichia coli. Other genera of bacteria that are part of coliforms are Klebsiella, Enterobacter Y Citrobacter.
Other bacteria such as Salmonella typhi, Leptospira sp., Yersinia sp., Vibrio cholerae Y Shigella sp. As well as fungi such as Aspergillus fumigatus Y Candida albicans, or viruses of the group of adenoviruses and rotaviruses.
Helminths are also common, including Ascaris lumbricoides, Fasciola hepatica, Taenia saginata Y Trichuris trichiura.
Domestic wastewater contains various polluting chemical elements to a greater or lesser extent. Among these are mainly nitrogen (ammonia, nitrites, nitrates), chlorides, sulfates and surfactants (soaps, detergents).
They may also contain aluminum, arsenic, barium, cadmium, cyanide, copper, chromium, iron, mercury, silver, lead, selenium, and zinc. Other relevant contaminants in domestic wastewater are drugs, disinfectants, antibiotics, analgesics and others..
Only about 20% of the municipalities in the State of Mexico have a domestic wastewater treatment system.
It is an Otomí-Nahua indigenous town located in the Capulhuac municipality in Mexico, which has drifted towards tourist and commercial activity. The Almaya lagoon is located there, which faces serious pollution problems, especially due to the discharge of domestic wastewater..
This pollution has generated eutrophication problems in the lagoon due to the contributions of nitrates and phosphates.Around the lagoon there are seven houses whose drains are not connected to the communal collector and therefore are a source of contamination.
To remedy the problem, a pilot project was implemented based on separating black and gray water. The gray water is led to a settling tank where air and ozone are injected..
These waters are reused for toilets, washing floors, cars and other purposes, to be later treated as sewage. For its part, the sewage is led to a solids trap, then to an anaerobic biodigester and air and ozone are injected..
One of the biggest problems of contamination of bodies of water in Colombia is due to the uncontrolled discharges of domestic wastewater. In many cases, despite the existence of septic tanks, sewage ends up leaking into rivers and groundwater.
The La Macana stream basin is located in the San Antonio de Prado district in the Medellín municipality. This basin presents problems of deterioration and environmental contamination, among these the contamination of the waters of the stream.
The main problem is the discharge of domestic wastewater into the stream, generating pollution, especially by total coliforms. The organic load supplied by domestic water discharges is 2,120 g / day where 62% come from homes with a septic tank and 38% are direct discharges.
Yet No Comments