Alternative schemes for the management of the sludge produced at Psyttalia WWTP

Abstract

The paper presents the conclusions of a study sponsored by the Ministry of Environment and Public Works and conducted by a research team of the National Technical University of Athens, aiming to investigate alternative management schemes for the sludge produced and expected after the operation of the second phase of the Psyttalia Sewage Treatment Works. The alternative management schemes examined include agricultural use, co-disposal of dewatered sludge with solid wastes, co-disposal of dried sludge with solid wastes, disposal of dewatered sludge at a separate landfill, disposal of dried sludge at a separate landfill, use of dried sludge as fuel for cement or electricity production and finally incineration. On the basis of the evaluation, the production of dried sludge which can be subsequently used for agricultural purposes or as a fuel stands out as the best long term option.

Phytoremediation as a Prospective Method for Rehabilitation of Areas Contaminated by Long-Term Sewage Sludge Storage: The Greek Experience

“…This is why in most cases wastewater sludge is not reused and is just left at the area of the WWTP. Thus, in Greece only 10 % of produced sludge is reused in agriculture (for example, at Rethymno WWTP (Chania, Crete) [1,2,8,16,25]), the rest 90 % is directed to landfills' disposal [18]. Wastewater sludge could be used not only as a fertilizer; dried sludge could be used in the active cement industry as a fuel substitute.…”

Atomized sludges via spray-drying at low temperatures: An alternative to conventional wastewater treatment plants

“…Production of dried sludge (by thermal or rotary drying) that can subsequently be used for agricultural purposes or as a fuel seems to be the best long-term option (Christoulas et al, 2000). However, in any case the economical value and/or usefulness of the dried sludge for these applications does not usually compensate for treatment, transportation and environmental costs (Spinosa et al, 2011).…”

Experimental investigation of phytoreclamation of sites affected by sewage sludge

“…According to Matthews (1999) and IEEP (2009) the country uses a very small quantity of sludge in agriculture (~10 %), and this mostly in the frame of research projects and pilot studies (Mamais et al, 2000). In addition to agricultural use, trials have been performed in the timber industry (Papapetrou, 2002), mine spoils reclamation (Brofas et al, 2000), vermiculture (Matthews, 1999) and cement industry (Christoulas et al, 2000). However, this is still very much at the experimental stage.…”

“…According to data from the Thessaloniki Water Supply and Sewerage Co, SA (EYATh), approximately 1000 tons of sewage sludge were used by the agricultural sector in Thessaloniki in 2010/11 and more than 7000 tons in 2012, and this trend is growing (Zambetoglou, K., personal communication). Besides the agricultural sector, sewage sludge can also be used as an amendment for mine spoils reclamation (Brofas et al, 2000) and in the cement industry (Christoulas et al, 2000). The latter is especially interesting for WWTPs in Athens and Thessaloniki, where the disposal of sludge at landfill sites can be seriously restricted due to the need for long transportation and the relatively poor quality of the sludge in terms of fairly high levels of concentration of heavy metal.…”