“Innovative method of improving water quality on the

example of Gniezno Stream and lake Jelonek”

Serwecińska L.1, Bednarek A.2 Gągała-Borowska I.1, Szklarek S.1, Kupiec J.M.3, Żeleźnik W.4, Draczyński Z.5,

Krucińska I.5, Mankiewicz-Boczek J.1,2

1. It was recorded: • significant reduction of nitrates after the water passes through the whole sedimentation and biofiltration system, which indicate that under the conditions created, the processes of nitrate conversion are properly carried out by means of denitrification and assimilation. Exception was the date 21.07.2016, after intense rainfall, when high concentrations of nitric nitrogen were recorded in all zones of the system • noticeable reduction of phosphates at the end of the system (point 8 - behind the biofilter) in comparision to the water in the Gniezno Stream (point 1) flowing into the system ( Fig.2a,2b) 2. It can be concluded that the solutions used within the system, such as the formation of a sedimentation zone, plant stocking, biofilter with a system of gabions favoring the settlement of microorganisms and the formation of biofilm, denitrification zone and application of microorganisms,have had a positive effect on the microbial state of the water entering lake Jelonek, after passing through the entire sed-bio system, both on the metabolic activity of whole microbial populations and on the sanitary purity of water (Fig.3, Fig. 5a,5b,5c)) 3. The results shown that the AWCD, H, and R ratios used in the functional differentiation evaluation were significantly different at each system site. In August the highest microbial activity (the highest catabolic potential) was in biofilter (point 6), and just behind it at the inflow to lake Jelonek (point 8), whereas the lowest metabolic activity was in the Gniezno Stream (Fig.5a,5b,5c) 4. During the monitoring period the occurrence of cyanobacteria was noted at all points and time of monitoring, but their quantity was low, and sporadic toxicity. Despite the periodic high amount and toxic cyanobacteria ( point 3a) there was no danger of toxicity to aquatic ecosystem and humans (lake Jelonek , point 8a) ( Fig.4a,4b).

Materials & Methods

Discussion & Conclusions

Study supported by : Project GEKON no. GEKON2/03/267948/21/2016.

Water samples were taken from the study area between April and November 2016. In-situ measurement for the temperature, pH and dissolved oxygen in the bioreactors were done using YSI Professional Plus probe.Chemical Nitrogen and phosphorus ions were determined using Ion Chromatography System (ICS1000, DIONEX Corportation) . All samples were filtered through GF/C filter (pore size ø 1.2μm) to remove the solid matter. Microbiological tests were performed in triplicate. The water samples were diluted (in water) or not diluted depending on the test group of microorganisms. Number of colony forming units (cfu) was evaluated on appropriate media (Actinomycetes - on Pochon medium, Lactobacilli on MRS medium,copiotrophs on nutrient agar, oligotrophs on 100x diluted nutrient agar. The abundance of coliforms and E.coli was determined using DST tests (Colilert 18, IDEXX Inc.US) according to the manufacturer's procedure. Metabolic potential of the heterotrophic microbial communities was characterized on EcoPlates (Biolog Inc.US) according to the manufacturer’s procedure, and Anova program was used to analyse the results. Molecular analysis using polymerase chain reaction was performed to identify the presence of (i) cyanobacteria of the Microcystis genus (based on 16S rRNA gene fragment, 250 bp), according to Neilan et al. and (ii) toxic genotypes of microcystin-producing cyanobacteria of the Microcystis genus (based on mcyA gene fragment, 405 bp), according to Gągała et al.

Results

The project uses an innovative and non-invasive approach to surface water recultivation using engineering , physical and biological method. The sedimentation-biofiltration system (sed-bio system) was constructed of biodegradable elements and consisted of two separate parts, located (a) in the pond, and (b) Gniezno Stream on the inflow to lake Jelonek . There were two gabions with mineral filters as a phosphorus sorbent, denitrification deposit installed in the part of the pond, also, several species of plants for phosphorus assimilation were planted for phytoremediation. Second biofilter, consisted of grid-stone gabions, limestone and denitrification barriers, phosphorus adsorbing mat , and partition system that slowed down the flow. After installation of biofilters , probiotic microorganisms were applied to the water tree times between June and September. Applied recultivation method caused improvement of physico-chemical, biological and sanitary parameters of water.

Fig. 1.Study site. Gniezno Stream and lake Jelonek - sed-bio system

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16S rRNA of Microcystis (250 bp)

Detection of cyanobacteria (Microcystis genus); KP – positive control; KN – negative control; M – marker; 21.07.2016: 1 – stream, 2 – pound, 3 – after biofilter, 4 – lake; 03.08.2016: 5 – stream, 6 – pound, 7 – after biofilter, 8 – lake.

• Neilan, B.A., Jacobs, D., del Dot, T., Blackall, L.L., Hawkins, P.R., Cox, P.T. & Goodman, A. E. (1997) rRNA sequences and evolutionary relationships among toxic and nontoxic cyanobacteria of the genus Microcystis. Int. J. Syst. Bacteriol. 47, 693–7 • Gagala I., Izydorczyk K., Jurczak T., Mankiewicz-Boczek J. 2012. The key parameters and early warning methods to identify presence of toxigenic blooms dominated by Microcystis aeruginosa in the Jeziorsko Reservoir (Central Poland). Fresenius Environ. Bull. 21(2): 295-303

Fig.4a. Molecular analysis using polymerase chain reaction to identify the presence of cyanobacteria of the Microcystis genus based on 16S rRNA gene fragment, 250 bp.

Fig.4b. Toxic genotypes of microcystin-producing cyanobacteria of the Microcystis genus (based on mcyA gene fragment, 405 bp)

Fig.2a,2b . The variability of the concentration of nitrate nitrogen and phosphates in water in the sed-bio system.

Fig. 5a. Average Well Color Development (AWCD) on individual system positions (1,2,4,6,8) in August 2016

Fig.5b. Average Functional Diversity (H) values at each system positions (1,2,4,6,8) in August 2016

Fig.5c. Average R (substrate richness) values at individual system positions (1,2,4,6,8) in August 2016

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Literature: