Water is undoubtedly a source of life, but almost equally it is an essential source for comfort. The use of water for activities that provide the comfort of a civilized life, implies a marked degradation of the natural qualities of the water can occur due to the introduction of pollutants into water, transforming it into wastewater. Wastewater is collected through complex sewage systems and transported to areas outside human settlements. For a long time this huge source of pollution was dumped into the flowing waters, into lakes and artificial ponds created for this purpose. The numerical increase of the human settlements has highlighted the high pollution capacity of the wastewater. People have realized that wastewater needs to be treated. The cost of treating wastewater is about twice the cost of drinking water. The expansion and modernization of wastewater treatment plants is the only way to reduce pollution and avoid infestation of surface water with wastewater. The current treatment technology involves obtaining significant quantities of sludge. The sludge collected from wastewater treatment is an important source of pollution. This may result in additional processing and storage costs. The present paper proposes a method of responsible management of the sludge can be obtained. Following dehydration, the sludge remains with a significant amount of water, about 70%, which makes it difficult to use. For the preparation of the sludge for use, the proposed method involves the use of a machine that will continue drying the sludge after the mechanical dehydration operation, until it is brought to 50% solid substance (SS). Dry sludge becomes much more attractive for use. If the treatment plant is well sized, it manages to eliminate those substances contained in the wastewater, which are harmful when their concentration is high. The use of dehydrated and dry sludge as fertilizer in agriculture can only be carried out with careful supervision of the process of collecting and purifying wastewater and drying properly. Those interested should be properly informed about the qualities of dehydrated sludge. The sludge contains nitrogen and phosphorus, chemical elements that recommend its use on agricultural land as fertilizer. The sludge resulting from the treatment of wastewater contains organic matter and nutrients, which can contribute to increasing soil fertility. The paper will present pictures of dried sludge to highlight the advantages of dry sludge. Laboratory determinations will show that, by drying, the substances contained in dehydrated sludge do not destroy. Also will be presented modern methods used in the European Union to illustrate how dry sludge can be disposal in agriculture.

sludge, dry sludge, agricultural, land, fertilizer

environmental engineering

Presentation: poster