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• Nicaragua

Home Biofilters - Biological filters to remove greywater nutrients
What problem does it solve?

In Latin American and Caribbean countries, 124 million people lack proper sanitation facilities and hygiene conditions are poor. Over 75% of sewage is dumped into the environment without treatment, contaminating the very water sources that are used for drinking (UNICEF 2008).

Sanitation is a means to expand human development. The problem of sewage and greywater is linked to sanitary conditions and there is a lack of sanitation for an overwhelming number of people in developing countries. Nearly one in every two people in developing countries lack access to improved sanitation—two and a half times the deficit for access to clean water. (Source: Human Development Report 2006, UNDP).

The lack of adequate sanitation is associated with various diseases like diarrhoea, which often cause rapid malnutrition and pneumonia. These diseases cause an overwhelming annual number of deaths, especially among children. Some of the most important benefits of sanitation include improved public health, a considerable decrease in diseases spread by water, and prevention of the premature death of millions of human beings.

The sanitation gap between developed and developing countries is an example of human development inequality. Due to inadequate technological capacity and financial resources, to address problems of sanitation developing countries need alternative and innovative technologies, consistent with the endemic conditions of their country.

Domestic biofilters as an alternative form of sanitation

In this context, domestic biofilters represent an alternative form of sanitation, and an environmentally friendly solution for the treatment of greywater. By reducing the negative impacts caused by the incorrect disposal of greywater and improving the quality of the water before being returned to nature, the living standards of people are improved and the natural beauty of the environment preserved.

By using home biofilters for the treatment of greywater, water can be reused (recycled), which is also beneficial from the financial standpoint. The resulting water from biofilter effluent, depending on the quality present at the end of treatment, can be used for other activities within the home, reducing potable water consumption by up to 20%. Bearing in mind that 80% of household water can be treated by this technology, this high volume of water is not sent to municipal treatment systems, reducing sewage treatment costs.

The main tools to build home biofilters can be found in homes and are readily available in the market. Biofilters are mainly built with local materials that are readily available, thus with a low cost; they are simple to make and require no skilled labour, so that with just a little technical monitoring families make them for themselves and adapt them to their needs. Since they can also be used for planting ornamental plants, they can be turned into a scenic garden outside the houses where they are located.

Biofilters have no maintenance costs. Routine maintenance is carried out by the same families that adopt the biofilter system. The system works entirely through the effects of gravity, so no electricity is required.

The difference between traditional and biofilter technologies is mainly one of environmental cost. Biofilters are more environmentally friendly because they reduce many of the pathogens to be found in the water, returning it to nature to recharge aquifers. In conventional technologies, the water that infiltrates into the soil still contains a large amount of organic matter and other pollutants that produce negative impacts on the soil and aquifers.