Anaerobic treatment of wastewater: State of the art

Anaerobic treatment and decomposition of organic matter (without the use of oxygen) is a very old technique. Since about 1970, the principle has also been used on a broader scale for the purification of wastewater. However, in the early days, the anaerobic technique was only used for treatment of wastewaters with a very high content of easily degradable organic substances. Consequently, the fist full-scale wastewater treatment plant was realized in the sugar industry. Later on, it became obvious that there were many more potential applications. Nowadays, thousands of full-scale anaerobic wastewater treatment plants are operational. They are used to treat wastewater produced in the agricultural industry and also in the chemical industry. Since 1985, there has also been a breakthrough in the area of purification of municipal wastewater. Successful plants are not only operational in tropical climates such as India, Colombia, and Brazil, but it has also proved to be possible to treat municipal wastewater successfully using anaerobic treatment in subtropical countries like Portugal. Anaerobic technology is used as it has benefits in comparison with other techniques, such as, for example, lower energy consumption, biogas production, production of less sewage sludge, lower space requirements, and lower overall costs. With respect to the future, it can be concluded that there is strong pressure to use anaerobic treatment on a much wider scale. There are still many areas where successful use might be possible. Examples of future application are treatment of industrial wastewaters that currently receive aerobic treatment. It is anticipated that anaerobic treatment, in part due to new technical modifications, will make a big jump ahead. New ideas and new applications have made anaerobic treatment into a competitive technology in new fields such as the chemical industry. It is therefore necessary to continue fundamental research on anaerobic treatment for a number of years. In the Netherlands, a foundation was established with the aim to provide financial support to research projects. The Netherlands Environmental Technology Foundation (NETFO) was initiated by a censortium consisting of institutes, consultants, and contractors. The NETFO objective is to enhance the international status of the Netherlands when it comes to the development of sustainable solutions to environmental problems.