Economic development and the introduction of new techniques in agriculture have led to the use of large amounts of fertilisers (mainly nitrates and phosphates) and agrochemicals. Consequently, the organic and inorganic concentration of these chemical compounds in soils has increased. Nitrates and phosphates in soil are highly soluble and percolate via irrigation water or rainfall into aquifers. In a similar way, the presence of pesticides in groundwater represents a significant problem in agricultural areas throughout Europe.
In the EU, groundwater is a strategic resource, especially for supplying water to urban areas. The Nitrates Directive (91/676/EEC) addressed the problem of groundwater contamination and obliged EU Member States to designate nitrate-vulnerable zones. The Drinking Water Directive (98/83/EC) and the Spanish legislation RD 140/2003 set a maximum allowable concentration for nitrates in groundwater of 50 mg/litre. According to the World Health Organisation (WHO, 1985), the consumption of water with high nitrate and nitrite concentrations can cause harmful health effects.
The LIFE ECOGRANULARWATER project would develop and demonstrate a new biological treatment method to remove organic and inorganic nutrients, such as pesticides and nitrates from water. This low-cost and environmentally-friendly technology would ensure a supply of clean drinking water in small towns.
The specific objectives of the project were to:
- Demonstrate on a pilot scale the feasibility of a sustainable and inexpensive aerobic granular technology that is energy self-sufficient through use of photovoltaic panels (The process will remove organic and inorganic pollutants from groundwater bodies that supply small communities, ensuring the release of nitrogen as N2 and organic matter as carbon dioxide);
- Implement biological technologies in groundwater treatment systems under strict biosafety controls; and
- Develop a business plan to address the European market for purification systems, and establish commercial and industrial strategies for the proposed technology. This will guarantee the technology’s transferability to other European regions, in particular through agreements with local authorities and public managers.
The project would be implemented in the municipality of Torre Cardela (Andalusia, Spain), an agricultural municipality severely affected by groundwater pollution.
The main goal to improve the quality of drinking water affected by organic and inorganic pollutants would boost compliance with the limit values established by the Drinking Water Directive (98/83/EC), the Water Framework Directive (2000/60/EC) and the Priority Substances Directive (2008/105/EC).
The LIFE ECOGRANULARWATER beneficiaries demonstrated the technical, environmental and economic feasibility of an innovative system based on aerobic granular technology for treating groundwater. Once the expected permit is obtained to use the drinking water produced to supply the population of Torre Cardela, in the Spanish province of Granada, the beneficiaries will be in a very good position to commercialise the technology.
The project’s technology could be replicated in many small towns and rural areas throughout Europe supplied with groundwater, which is frequently polluted with nitrate and pesticides. The project team developed a new aerobic granular technology for biological treatment of water that removes organic and inorganic pollutants with maximum health guarantees at low cost, with high energy efficiency, and with no environmental impact. This technology would ensure a clean drinking water supply in small towns under strict biosafety control measures.
The Life Cycle Analysis (costs and environmental) conducted with the information gathered from the pilot plant trials showed that the project technology is feasible, with the following advantages compared to the conventional reverse osmosis (RO) method:
- The project plant consumes only 0.37 kWh/m3 of water produced, while the RO consumes 2.05 kWh/m3;
- For every m3 of water treated with RO, 0.42 m3 of water is generated as brines, while with the project plant this is reduced to 0.02 m3. Therefore, brines will not be produced, avoiding pollution in water bodies;
- The project plant emits 0.38 kg CO2eq/m3 of water produced, while the RO plant emits 1.02 kg CO2eq/m3 of water produced (reduction of 62.75 %);
- Compared to RO, the project plant represents an average reduction of environmental footprint of 66.42% in the different impact categories analysed (e.g. carbon footprint, photochemical ozone formation, acidification, freshwater eutrophication, ecotoxicity);
- The analysis of economic and financial costs showed that producing drinking water with the project system is 45% cheaper than with RO.
Furthermore, the design of the plant is scalable, while the bioreactor dimensions are not unique, giving a certain flexibility in diameter-height ratio. This flexibility allows the design of plants that are adapted to the size of population to be supplied with drinking water.
The technology contributes to EU policy, such as the Drinking Water Directive and the Nitrates Directive, by helping keep pollutant concentrations below set thresholds. Socio-economic benefits include improved human health and drinking water safety, lower cost of treating water, and the prevention of eutrophication in water bodies due to the reduced release of brines from treatment plants.
Further information on the project can be found in the project's layman report (see "Read more" section).