A natural filter substrate for efficient phosphorus removal from wastewater - column studies
2003 (English)In: Scientific Papers of the Agricultural University of Crakow - Environmental Engineering, ISSN 1233-569X, no 24, 397-404 p.Article in journal (Refereed) Published
Sorption to the bed substrate is a major phosphorus (P) removal mechanism in constructed wetlands. Hence it is important to select a substrate with high sorption capacity. A column experiment was performed where Polonite®, a product from opoka (a silica-calcite sedimentary rock from Poland) was mixed with Sphagnum peat in a weight proportion of 1:0.8 (column 2, 4) and 1:0.4 (column 3).Secondary treated wastewater with a mean soluble phosphorus (P-PO4) concentration of 5.1 mg·dm-3 was supplied during 378 days by gravity to four columns, 0.3 m in diameter and filled with substrate to 0.5 m. Column1 was filled solely with peat. Two different grain sizes of Polonite®: 0.05-0.2 mm (column 2, 4) and 2-6 mm (column 3) were used in the experiment. The hydraulic residence time varied from 36 to 48 hours during the experiment. The substrate in column 1 and 2 were kept under un-saturated conditions, while saturated conditions prevailed in columns 3 and 4. The column filled with peat showed an overall P-PO4 removal of 18% and an average effluent concentration of 4.2 mg· dm-3. However, after four months of wastewater discharge, the colour of the effluent from column1 exceeded 10000 mg Pt dm-3 and no further analysis of P was carried out. In the other three columns, where Polonite® was present, the average removal was 99%. The mean concentration of P-PO4 in effluent water from these columns was only 0.03 mg dm-3. Conditions of saturated and un-saturated substrates did not reveal any difference in P-sorption capacity. The results obtained show that the incorporation of the reactive media Polonite® into a peat matrix will enhance the long-term P-sorption capacity significantly.
Place, publisher, year, edition, pages
Kraków: Wydawnictwo AR w Krakowie , 2003. no 24, 397-404 p.
IdentifiersURN: urn:nbn:se:kth:diva-82482OAI: oai:DiVA.org:kth-82482DiVA: diva2:498293
NR 201408052012-02-122012-02-112012-02-12Bibliographically approved