Properties of ashes formed after the combustion of sewage sludge

Abstract

The objective of the research presented in the paper was to analyze the ash formed in the process of incineration in the thermal sewage sludge treatment facility being a part of Sitkówka-Nowiny wastewater treatment plant, located in the vicinity of Kielce. The research involved the investigation of heavy metal and total phosphorus content, leachability of certain ions and X-ray phase analysis. The comparison of the obtained results with those available in literature revealed similarities in the crystallographic structure of ashes from different treatment plants. Then, the differences observed in the content of heavy metals in particular ashes are related to the composition of sewage flowing into treatment plants. Attention was also paid to a significant sulphate content revealed in the leachability analysis, found both in the ash from Sitkówka-Nowiny treatment plant and in the ash analyses results available in the literature sources. High sulphate concentration can limit the use of ash for construction purposes.

Effect of the presence ofActinomycetesin the activated sludge on the quality of the treated wastewater

“…Phosphorus speciation analysis of the suspended solids was performed by the Golterman method [3]. This method is a sequential extraction scheme where each extraction stage is followed by filtering the sample and its further treatment with a reagent of increasing extraction force [4]. In the first stage the suspended solids sample which was passed through a cellulose filter was subjected to extraction with a solution of CaNa 2 -EDTA for 4 h. In the second stage the residue formed after the first stage was subjected to extraction with a solution of Na 2 -EDTA for 18h.…”

“…In the examined treated wastewater the total suspended solids constituted 1.9 g.d.w/dm 3 , and therefore the content of particular phosphorus fractions was also expressed in mg P/dm 3 . According to Golterman the bioavailable phosphorus forms are represented by the fractions Ca-EDTA and Na-EDTA bound to sludge particles [4]. The amount of phosphorus, which is potentially assimilated by the river phytoplankton can be estimated by adding together the content of bioavailable phosphorus forms (fractions Ca-EDTA and Na-EDTA) contained in the sludge (Table 3) and the orthophosphate concentration expressed as elemental phosphorus ( In the case of a large amount of organic matter infiltrating the surface water with the treated sewage, the execution of phosphorus speciation analysis in the separated suspension allows more accurate estimation of the concentration of phosphorus that can be assimilated by the microorganisms and cause eutrophication.…”

Utilizing Sewage Sludge Slag, a By-Product of the Circulating Fluidized Bed Combustion Process, to Efficiently Remove Copper from Aquatic Environment

“…Hence, it is highly probable that the adsorption of Cu(II) ions may be associated with ion exchange and/or complexation by bonding with oxygen groups. The probable ion exchange mechanism between H + and Cu 2+ ions can be proposed by Equations ( 8)- (10).…”

“…The neutralization of sewage sludge (SS) by incineration is a promising method due to limitations in the use of SS containing excessive concentrations of heavy metals. The method using heat with energy recovery is perceived as one of the most effective methods of neutralizing SS due to its energy and environmental benefits, including waste mass reduction, energy use of SS treatment, low susceptibility to changes in waste composition, system stability, minimization of odors, and the possibility of using by-products of fly ash and slag as filter materials or as an additive to building materials, including concrete, asphalt, bricks, concrete blocks, and hollow blocks [10,11]. The limitations include the formation of by-products, the quantity and quality of which depend on the chemical composition of SS, combustion conditions, and flue gas treatment technology, as well as high operating costs and the costs of building incineration plants [12,13].…”