Leaching of nitrogen, phosphorus, TOC and COD from the biosolids of the municipal wastewater treatment plant of Thessaloniki

Abstract

Biosolids from the WWTP of Thessaloniki were examined for the leaching of phosphorus (as PO4(3-) -P), nitrogen (as NH4+ (-N) and NO3- (-N)), and organic matter (as TOC and COD), using two tests: (1) a pH static leaching test and (2) a characterization test, relating contaminant release to the liquid to solid (L/S) ratio. Moreover, a Microtox toxicity test was conducted, to examine the pH dependency of the toxicity of the sludge leachate on the Vibrio fischeri bacterium. Maximum phosphorus release was observed at pH < 3 and at pH > 10. Ammonium nitrogen exhibited maximum leachability at near neutral pH conditions, while nitrate nitrogen exhibited a mild increase in the leachate, as the leachant pH increased from 2 to 12. Both TOC and COD exhibited an increase in the leachate concentration, as the leachant pH was increased from 2 to 12. Ecotoxicological analysis showed that maximum toxicity occurred at very low and very high pH-conditions. As liquid-to-solid ratio increased, the leachate concentration (in mg/l) of all parameters studied decreased. The results of the study were used to conduct a release assessment estimate for the case of Thessaloniki.

Occurrence of estrogen hormones in biosolids, animal manure and mushroom compost

“…Leaching of nutrients such as nitrogen and phosphorus from land application of manure and municipal biosolids has been extensively studied (Batziaka et al 2008), but there is very limited information available in the literature on the leaching of hormones from land applied biosolids, animal manure and agricultural wastes. In this study, the presence of seven natural and synthetic steroid hormones in municipal biosolids, SMC, and animal manure was examined.…”

Effect of sewage sludge and synthetic fertilizer on pH, available N and P in pasture soils in semi-arid area, Turkey

“…In year 2008, in spite of the repeated synthetic N application, there occurred a decrease in surface soil nitrogen and an increase in subsoil nitrogen. The pH level of the experiment area was between 7.3 and 9.2 and this values can be accepted as quite ideal when the optimal pH values are 2<pH>12 which Batziaka et al (2008) indicated for nitrogen usefulness and mobility. Therefore, both the property of nitrogen in nitrate to be leached out rapidly and the pH value of soil can be put forth as the factors facilitating the leaching of nitrogen to the subsoil.…”

“…Thus, soil erosion can be minimized as a consequent of prevention of overland flow. The release of phosphorus and nitrogen is closely related with pH; maximum phosphorus release was observed at pH <3 and pH >10 and ammonium nitrogen was leached at near neutral pH conditions, while nitrate nitrogen increased as the leachant pH was increased from 2 to 12 (Batziaka, 2008). However, Arvas (2005) and Keramati et al (2010) reported that sewage sludge application decreased alkaline soil pH because of the high buffering capacity of calcareous soil.…”

State of the Art in Technologies of the Biogas Production Increasing During Methane Digestion of Sewage Sludge

“…Unit WWTP in Brazil [3] WWTP in Thesaloniki, Greece [6] WWTP according to the data given by [5] Compared to raw sludge the excess sludge one contains higher concentrations of phosphorus (it is especially noticeable in WWTP with BNR removal). Because of relatively high organic matter content both kinds of sewage sludge are well putrescible and in WWTP undergo methane digestion.…”