Abstract

Due to the resources of phosphorous are limited and are exhausted in the next 30 years the management of the resources is become current issue. Most of the phosphorus compounds is lost forever, because it is discharged with sewage into surface waters, causing eutrophication and in this way causing a further problem and challenge. On the other hand, there is a considerable need for phosphorus compounds, primarily in bioavailable forms. The aim of the study is to compare the capacity to retain phosphorus compounds on different sorption materials. During the experiments both synthetic and real wastewater are used. The synthetic wastewater simulates the composition of the reject water (RW) generated during the mechanical dewatering of the digested sewage sludge, and the real RW comes from WWTP in Gdansk. The research is carried out within the subtask 2.3 of the project entitled “Integrated technology for improved energy balance and reduced greenhouse gas emissions at municipal wastewater treatment plants” with the acronym “BARITECH” co-funded by the Norwegian funds, under the Polish-Norwegian Cooperation Research carried out by the National Centre for Research and Development (197025/37/2013). For the investigation in dynamic conditions (flow through the column) four kinds of material have been selected. One of the column constituting control filled with washed gravel (2-8 mm). Other columns filled with natural material: (i) calcium – silica rock subjected to heat treatment, and waste materials, from water purification plan- the substrate form the filter for iron and manganese removal: (ii) from the first stage of iron removal (Fe), and (iii) the second stage of manganese removal (Mn). Substrate (ii and iii) are covered by iron oxide or manganese oxide respectively and both of them are proven to be good in bounding of P-compounds. In steady conditions the investigation were carried out with Phoslock which is chemically lanthanum clay. The result of investigation are related to the determination of the sorption capacity with respect to the analysed content of phosphorus compounds in dynamic conditions of flow and for stable conditions the determination of hydraulic load and way and time of mixing. For the synthetic wastewater the removal efficiency of phosphorous was 99.8% while for reject water (RW) generated during the mechanical dewatering of the digested sewage sludge was lower and equal to 85%.

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Authors (4)