Review on mechanisms and efficiency of removal of microbiological contaminants in constructed wetlands

• Autorzy: Łuczkiewicz A. , Kulbat E. , Olańczuk-Neyman K. , Quant B. , Rymszewicz A.

Warianty tytułu

PL

Mechanizmy i efektywność usuwania zanieczyszczeń mikrobiologicznych na filtrach gruntowo-roślinnych

• Języki publikacji: EN

Abstrakty

EN

Constructed wetlands (CW) have been considered as a waste and a stormwater treatment systems for small communities or for areas with unsteady sewage flow conditions. Several investigations were undertaken for estimation suspended solids, organic matter and nutrients efficiency removal but only few focused on retention of microorganisms in constructed wetlands. In this review mechanisms of elimination of viruses, indicator bacteria as well as helminth eggs and protozoan parasites are discussed. Generally the retention and the removal efficiency of microorganisms in the wetlands systems can be attributed to the combination of filtration, sorption and inactivation, which are controlled by the retention time and the flow condition. Filtration depends on the beds' matrix and involves the physical blocking of movement through the pores smaller than microorganisms. Binding between the solid surfaces and the microorganisms (especially bacteria cells) is mainly affected by the chemistry of the bed particles and the properties of the microbial organisms. The rate of microorganisms inactivation is probably also influenced by abiotic and biotic factors. The majority of allochtonic microorganisms die off after introduction to the "natural" treatment systems such as wetlands because of the abiotic stress. But even subpopulations better suited for survival and colonization, can also be eliminated because of predation. The bacterial phages, protozoa and nematodes as well as inhibitory substances secreted by other bacteria may also be a reason of reduction of the enteric bacteria in the wetland conditions. Also macrophytes in the wetland system are regarded as an essential in hygienisation of wastewater. However bacterial elimination in constructed wetlands is regarded as a highly efficient (> 99.9%), the final number of bacteria in the treated sewage can still affect the environmental ecosystems.

PL

Hydrofitowa metoda jest stosowana do oczyszczania wód opadowych, ścieków bytowo-gospodarczych z pojedynczych gospodarstw oraz odcieków ze składowisk komunalnych. Większość publikowanych wyników badań dotyczących skuteczności oczyszczania ścieków na złożach gruntowo-roślinnych koncentruje się głównie na zagadnieniach usuwania zawiesiny, substancji organicznych i pierwiastków biogennych, natomiast nieliczne tylko prace prezentują wyniki stanu sanitarnego odpływów. W pracy scharakteryzowano zasadnicze mechanizmy przyczyniające się do usuwania zanieczyszczeń mikrobiologicznych ze ścieków oczyszczanych w różnych konfiguracjach systemów hydrofitowych oraz przedstawiono ich efektywność w eliminacji bakterii wskaźnikowych. Obniżanie liczby bakterii pochodzenia kałowego, cyst pierwotniaków i jaj helmintów w procesach oczyszczania ścieków na filtrach gruntowo-roślinnych jest efektem ich zatrzymywania, eliminacji oraz obumierania. Zatrzymywanie tego typu allochtonicznych zanieczyszczeń w ośrodku porowatym jest efektem fizykochemicznych procesów, takich jak: sedymentacja, filtracja i adsorpcja, na które wpływają warunki przepływu i czas zatrzymania. Do obniżania liczby mikroorganizmów (eliminacji) przyczyniają się biologiczne procesy, wśród których do najważniejszych należą: drapieżnictwo, antagonizm, konkurencja o substancje pokarmowe lub pierwiastki śladowe i liza przy udziale bakterii lub wirusów. Obumieranie jest natomiast skutkiem niekorzystnego wpływu różnorodnych czynników abiotycznych, takich jak: odczyn (pH), temperatura, działanie promieniowania UV, brak wilgoci. Ponadto istotną rolę w usuwaniu zanieczyszczeń mikrobiologicznych odgrywają makrofity porastające systemy hydrofitowe, których skuteczność jest w znacznym stopniu związana z porą roku. Makrofity zmniejszają przepływ ścieków i sprzyjają sedymentacji drobnych cząstek zawiesiny wraz z zatrzymanymi na nich bakteriami. Również liczne substancje produkowane przez ich system korzeniowy względnie produkowane przez populacje bakterii zasiedlające korzenie są toksyczne dla bakterii pochodzenia kałowego. Z drugiej zaś strony makrofity chronią mikroorganizmy przed szkodliwym wpływem promieniowania UV. Wprawdzie skuteczność usuwania bakterii wskaźnikowych na filtrach gruntowo-roślinnych jest zbliżona do uzyskiwanej w wysoko efektywnych oczyszczalniach ścieków, to jednak odpływy z obu typów oczyszczalni nadal budzą zastrzeżenia pod względem mikrobiologicznym.

Słowa kluczowe

EN

wastewater; constructed wetlands; microorganisms; microbiological contaminants removal

PL

ścieki; filtry gruntowo-roślinne; mikroorganizmy; usuwanie zanieczyszczeń mikrobiologicznych

• Wydawca: Wydawnictwo Politechniki Częstochowskiej
• Czasopismo: Inżynieria i Ochrona Środowiska
• Rocznik: 2006
• Tom: T. 9, nr 4
• Strony: 349--363
• Opis fizyczny: Bibliogr. 88 poz.

Twórcy

autor

Łuczkiewicz A.

autor

Kulbat E.

autor

Olańczuk-Neyman K.

autor

Quant B.

autor

Rymszewicz A.

• Gdańsk University of Technology, Faculty of Civil and Environmental Engineering, ul. G. Narutowicza 11/12, 80-952 Gdańsk

Bibliografia

• [1] Obarska-Pempkowiak H., Application of the hydrobiological method based on soil filters and wastewater ponds to purification of municipal sewage, Budownictwo Wodne XXXVIII, Zesz. Nauk. PG 1992, 489, 1-95 (in Polish).
• [2] Stottmeister U., Wießner A., Kuschk P., Kappelmeyer U., Kästner M, Bederski O., Müller R.A., Moorman H., Effects of plants and microorganisms in constructed wetlands for wastewater treatment, Biotechnology Advances 2003, 22, 93-117.
• [3] Gersberg R.M., Gearheart R.A., Ives M., Pathogen removal in constructed wetlands, (in:) Constructed Wetlands for Wastewater Treatment. Municipal, Industrial and Agricultural, D.A. Hammer (ed.), Lewis Publishers Inc., Michigan, USA 1989, 431-445.
• [4] Gammack S.M., Paterson E., Kemp J.S., Cresser M.S., Killham K., Factors affecting the movement of microorganisms in soil, [In:] Soil biochemistry, G. Stotzky, J.M. Bollag, (eds.), Marcel Dekker, New York 1992, 263-305.
• [5] Green M.B., Griffin P., Seabridge J.K., Dhobie D., Removal of bacteria in subsurface flow wetlands, Wat. Sci. Technol. 1997, 35, 109-116.
• [6] Rudolfs W., Frank L.L., Ragotzkie R.A., Literaturę review on the occurrence and survival of enteric, pathogenic and relative organisms in soil, water, sewage, and sludge and on vegetation, Sewage Ind. Waste. 1950, 22, 1261-1281.
• [7] Fenlon D.R., Ogden I.D., Vinten A., Svoboda L, The fate of Escherichia coli and E.coli 0157 in cattle slurry after application to land, Soc. Appl. Microbiol. Symp. 2000, Ser. 29, 149S-156S.
• [8] Gagliardi J.V., Karns J.S., Persistence of Escherichia coli O157:H7 in soil and on plant roots, Environ. Microbiol. 2002, 4, 89-96.
• [9] Perkins J., Hunter C, Removal of enteric bacteria in surface flow constructed wetlands in Yorkshire England, Wat. Res. 2000, 6, 1941-1947.
• [10] Ausland G., Stevik T.K., Hanssen J.F., K0hler J.C., Jenssen P.D., Intermittent filtration of wastewater - Removal of fecal coliforms and fecal streptococci, Water Res. 2002, 36, 3507-3516.
• [11] Steer D., Fraser L., Boddy J., Seibert B., Efficiency of smali constructed wetlands for subsurface treatment of single-family domestic eftluent, Ecol. Eng. 2002, 18, 429-440.
• [12] Baeder-Bederski O., Dürr M" Borneff-Lipp M., Netter R., Kuschk P., Mosig P., Daeschlein G., Müller R.A., Reduction of microorganisms in municipal sewage by means of planted and unplanted soil filters, 9th International Conference on Wetland System for Water Pollution Control, Wetland System, Avignon (France), 26-30th of September 2004, 2, 435-441.
• [13] Hagendorf U., Diehl K., Feuerpfeil I., Hummel A., Lopez-Pila J., Szewczyk R., Microbiological investigations for sanitary assessment of wastewater treated in constructed wetlands, Wat. Res. 2005, 39, 4849-4858.
• [14] Steer D.N., Fraser L.H., Seibert B.A., Cell-to-cell pollution reduction effectiveness of subsurface domestic treatment wetlands, Bioresource Technology 2005, 96, 969-976.
• [15] Thurston J.A., Gerba C.P., Foster K.B., Karpiscak M.M., Fate of indicator microorganisms, Giardia and Cryptosporidium in subsurface flow constructed wetlands, Wat. Res. 2001, 35, 1547-1551.
• [16] Quiňónez-Diaz M.J., Karpiscak M.M., Ellman E.D., Gerba Ch.P., Removal of pathogenic and indicator microorganisms by a constructed wetland receiving untreated domestic wastewater, J. Environ. Sci. Health 2001, 36, 1311-1320.
• [17] Thurston-Enriquez J.A., Gilley J.E., Eghball B., Microbial quality of runoff following land application of cattle manure and swine slurry, J. Water Health 2005, 3, 157-171.
• [18] Crabill C, Donald R., Snelling J., Foust R., Southam G., The impact of sediment faecal coliform reservoirs on seasonal water quality in Oak Creek, Arisona, Wat. Res. 1999, 33, 2163-2171.
• [19] Harvey R.W., Parameters involved in modeling movement of groundwater, (in:) Modeling the environmental fate of microorganisms, C.J. Hurst (ed.), Washington D.C., Am. Soc. for Microbiol. 1991,89-114.
• [20] Williams J., Bahgat M., May E., Ford M, Butler J., Mineralisation and pathogen removal in gravel bed hydroponic constructed wetlands for wastewater treatment, Wat. Sci. Technol. 1995, 32, 49-58.
• [21] Grimason A.M., Smith H.V., Thitai W.N., Smith P.G., Jackson M.H., Gridwood W.A., Occurrence and removal of Cryptosporidium spp. oocysts and Giardia spp. cyst in Kenian waste stabilisation ponds, Wat. Sci. Technol. 1993, 27, 97-104.
• [22] Stott R., Jenkins T., Bahgat M., Shslaby L, Capacity of constructed wetlands to remove parasite eggs from wastewaters in Egipt, Wat. Sci. Technol. 1999, 40, 117-123.
• [23] Gerba C.P., Thurston J.A., Falabi J., Watt P.M., Karpiscak M.M., Optimization of artificial wet-land design for removal of indicator microorganisms and pathogenic bacteria, Wat. Sci. Technol. 1999, 40, 363-368.
• [24] Müller R., Baeder-Bederski O., Kuschk P., Buschking M., Schulz-Berendt, Reduction of microorganisms in municipal waste water using planted soil filters. Part I, International Workshop Wastewater Hygienisation in Constructed Wetlands, Ponds and Related System, 6-7 November 2003, Leipzig, 20.
• [25] Gerba C.P., Bitton G., Microbial pollutants: their survival and transport pattern to ground water, (in:) Groundwater Pollution Microbiology, G. Bitton i C.P. Gerba (eds.), Wiley, New York, 1984, 65-88.
• [26] Garcia J., Vivar J., Aromir M., Mujeriego R., Role of hydraulic retention time and granular medium in microbial removal in tertiary treatment reed beds, Wat. Res. 2003, 37, 2645-2653.
• [27] Jang L.K., Sharma M.M., Findley J.E., Chang P.W., Yen T.F., An Investigation of the Transport of Bacteria through Porous Media, Proc. Int. Conf. Microbial Enhanced Oil Recovery, Afton, OK, May 16-21, 1982, DOE Conf-8205140, 60-70.
• [28] Dale N.G., Bacteria in intertidal sediments: Factors related to their distribution, Limnology and Oceanography 1974, 19, 509-518.
• [29] Tietz A., Losert A., Perez Lopez M.C., Ferrer Laporta C, Haberl R., Zibuschka F., Assessment of bacterial removal efficiency of pilot-scale constructed wetlands, International Workshop Wastewater Hygienisation in Constructed Wetlands, Ponds and Related Systems, 6-7 November 2003, Leipzig, 45.
• [30] Feierabend J.S., Wetlands the lifeblood and the wildlife, (in:) Constructed Wetlands for Wastewater Treatment. Municipal, Industrial and Agricultural, D.A. Hammer (ed), Lewis Publishers Inc., Michigan, USA 1989, 431-445.
• [31] Mandi L., Ouazzani N., Bouhoum K., Boussaid A., Wastewater treatment by stabilisation ponds with and without macrophytes under arid climate, Wat. Sci. Technol. 1993, 28, 177-181.
• [32] Ksoll W.B., Wand H., Kuschk P., Kastner M., Reduction of Escherichia coli cells in synthetic wastewater with hydroponically grown Carex gracilis plants, International Workshop Wastewater Hygienisation in Constructed Wetlands, Ponds and Related System. 6-7 November 2003, Leipzig, 38.
• [33] Wand H., Vacca G., Kuschk P., Kruger M., Kästner M., Removal of bacteria from axenic cells suspensions as well as from domestic wastewater by filtration on sand columns planted with helophytes, International Workshop Wastewater Hygienisation in Constructed Wetlands, Ponds and Related System, 6-7 November 2003, Leipzig, 43.
• [34] Warren A., Stott R., Decamp O., The role of predation by protozoa and rotifers in the removal of bacteria and parasites from wastewaters in constructed wetlands, International Workshop Wastewater Hygienisation in Constructed Wetlands, Ponds and Related System, 6-7 November 2003, Leipzig, 27.
• [35] Decamp O., Warren A., Bacterivory in ciliates isolated form constructed wetlands (reed beds) used for wastewater treatment, Wat. Res. 1998, 32, 1989-1996.
• [36] Wright D.A., Killham K., Glover L.A., Prosser J.I., Role of pore size location in determining bacterial activity during predation by protozoa in soil, Appl. Environ. Microbiol. 1995, 61, 3537-3543.
• [37] Davies C.M., Bavor H.J., The fate of stormwater-associated bacteria in constructed wetland and water pollution control pond systems, J. Appl. Microb. 2000, 89, 349-360.
• [38] Decamp O., Warren A., Investigation of Escherichia coli removal in various designs of subsurface flow wetlands used for wastewater treatment, Ecol. Eng. 2000, 14, 293-299.
• [39] Decamp O., Warren A., Free-living amoebae from constructed wetlands used for wastewater treatment, Quekett J. Microsc. 1996, 37, 660-665.
• [40] Huysman F., Verstraete W., Water-facillated transport of bacteria in unsaturated soil columns: influence of celi surface hydrophobicity and soil properties, Soil Biol. Biochem. 1993, 25, 83-90.
• [41] Gonzalez J., Iriberri J.M., Egea J., Barcina L, Differential rates of digestion of bacteria by freshwater and marine phagotrophic protozoa, Appl. Environ. Microbiol. 1990, 56, 1851-1857.
• [42] Stott R., May E., Matsushita E., Warren A., Protozoan predation as a mechanism for the removal of Cryptosporidium oocysts from wastewater in constructed wetlands, Wat. Sci. Technol. 2001, 44, 191-198.
• [43] Haule A.T., Pratap H.B., Katima H.J.Y., Mbwette T.S.A., Soren N.N., Njau K., The study of potential indigenous emergent macrophytes for faecal coliform removal in horizontal subsurface flow constructed wetlands (HSSFCW) in Tanzania, International Workshop Wastewater Hygienisation in Constructed Wetlands, Ponds and Related System, 6-7 November 2003, Leipzig, 11.
• [44] Gersberg R.M., Brenner R., Lyon S.R., Elkins B.V., Survival of bacteria and viruses in municipal wastewater applied to artificial wetlands, (in:) Aąuatic Plants for Water Treatment and Resource Recovery, K.R. Reddy, W.H. Smith (eds.), Magnolia Publishing, Orlando, FL, 1987, 237-245.
• [45] Rivera F., Warren A., Ramirez E., Decamp O., Bonilla P., Gallegos E., Calderon A., Sanchez J.T., Removal of pathogens from wastewater by the root zone method (RZM), Wat. Sci. Technoi. 1995,32,211-218.
• [46] Garcia M., Becares E., Bacterial removal in three pilot scalę wastewater treatment system for rural areas, Wat. Sci. Technol. 1997, 28, 311-315.
• [47] Hench K.R., Bissonnette G.K., Sexstone A.J., Coleman J.G., Grbutt K., Skousen J.G., Fate of physical, chemical, and microbial contaminants in domestic wastewater following treatment by smali constructed wetlands, Wat. Res. 2003, 37, 921-927.
• [48] Karathanasis A.D., Potter C.L., Coyne M.S., Vegetation effects on fecal bacteria, BOD, and suspended solid removal in constructed wetlands treating domestic wastewater, Ecol. Eng. 2003, 20, 157-169.
• [49] Wong T.F.H., Breen P.F., Somes N.L.G., Ponds vs wetlands - performance considerations in stormwater quality management, Proceedings of the Comprehensive Stormwater and Aquatic Ecosystem Management First South Pacific Conference, 22-26 February 1999, Auckland, 2, 223-231.
• [50] Karim M.R., Faezeh D.M., Karpiscak M.M., Gerba C.P., The persistence and removal of enteric pathogens in constructed wetlands, Wat. Res. 2004, 38, 1831-1834.
• [51] Bowen G.D., Rovira A.D., Microbial colonization of plant roots, Annual. Rev. Phytopathol. 1976, 12, 181-197.
• [52] Seidel K., Macrophytes and water purification, (in:) Biological Control of Water Pollution, J. Tourbier, R.W. Pierson (eds.), Univ. of PennsyWania Press, Philadelphia 1976.
• [53] Vincent G., Dallaire S., Lauzer D., Antimicrobial properties of roots exudate of three macrophytes: Mentha aquatica L., Phragmites australis (Cav.) Trin. and Scirpus lacustris L, (in:) Preprinted Wetland System for Water Pollution Control, Proc. Conf., ICWS Secretariat, Guangzhou, P.R. China 1994, 290-296.
• [54] Broadbent P., Baker K.F., Waterworth Y., Bacteria and actinomycetes antagonistic to fungal roots pathogens in Australian soils, Aust. J. Biol. Sci. 1971, 24, 925-944.
• [55] Ogden I.D., Fenlon D.R., Vinten A.J., Lewis D., The fate of Escherichia coli 0157 in soil and its potential to contaminate drinking water, Int. J. Food Microbiol. 2001, 66, 111-117.
• [56] Gagliardi J.V., Krans J.S., Leaching of Escherichia coli 0157:H7 in diverse soils under various agricultural management practices, Appl. Environ. Microbiol. 2000, 66, 877-883.
• [57] Bolton D.J., Byrne CM., Sheridan J.J., McDowell D.A., Blair I.S., The survival characteristics of non-toxigenic strain of Escherichia coli O157.H7, J. Appl. Microbiol. 1999, 86, 407-411.
• [58] Chan K., Wong S.H., Mak C.Y., Effects of bottom sediments on the survival of Enterobacter aerogenes in seawater, Marinę Pollution Bulletin 1979, 10, 205-210.
• [59] van Loosdrecht M.C.M., Lyklema J., Norde W., Zehnder A.J.B., Bacterial adhesion. A physico-chemical approach, Microbial. Ecol. 1989, 17, 1-15.
• [60] Scholl M.A., Mills A.L., Herman J.S., Hornberger G.M., The influence of mineralogy and solution chemistry on the attachment of bacteria to representative aquifer materials, J. Contam. Hydrol. 1990, 6, 321-336.
• [61] Mills A.L., Herman J.S., Hornberger G.M., DeJesus T.H., Effect of solution ionic strength and iron coatings on minerał grains on the sorption of bacterial cells to quartz sand, Appl. Environ. Microbiol. 1994, 60, 33000-33006.
• [62] Marshall K.C., Electrophoretic properties of fast and slow growing species of Rhizobium, Aust. J. Biol. Sci. 1967, 20, 429-438.
• [63] Mc Eldowney S., Flechter M., The effect of growth conditions and surface characteristics of aquatic bacteria on their attachment to soil surfaces, J. Gen. Microbiol. 1986, 132, 513-523.
• [64] Harden V., Harris I, The isoelectric point of bacterial cells, J. Bacteriol. 1953, 65, 198-202.
• [65] Ellwood D.C., Keevil C.W., Marsh P.D., Brown C.M., Wardell J.N., Surface-associated growth, Philos. Trans. R. Soc. London 1982, 297, 517-532.
• [66] Scholl M.A., Harvey R.W., Laboratory investigations on the role of sediment surface and groundwater chemistry in the transport of bacteria through contaminated sandy aąuifer, Environ. Sci. Technol. 1992, 26, 1410-1417.
• [67] Stumm W., Morgan J., Aquatic Chemistry, Willey, New York 1981.
• [68] Sharma M.M., Chang Y., Yen TF., Reversible and irreversible surface charge modification of bacteria for facilitating transport through porous media, Coli. Surf. 1985, 16, 193-206.
• [69] Johnson W.P., Logan B.E., Enhanced transport of bacteria in porous media by sediment-phase and aąueous-phase natural organic matter, Wat. Res. 1996, 30, 923-931.
• [70] Vega E., Lesikar B., Pillai S.D., Transport and survival of bacteria and viral tracers through submerged-flow constructed wetland and sand-filter system, Bioresource Technology 2003, 89, 49-56.
• [71] Adler J., Chemotaxis in bacteria, Science, 1966, 153, 708-716.
• [72] Barton J.W., Ford R.M., Determination of effective transport coefficients for bacteria migration in sand columns, Appl. Environ. Microbiol. 1995, 61, 3329-3335.
• [73] Busscher H.J., Bellon-Fontaine M.-N., Sjollema J., van der Mai H.C., Relative importance of surface free energy as a measure of hydrophobicity in bacterial adhesion to solid surfaces, [In:] Microbial cells surface hydrophobicity, R.J. Doyle, M. Rosenberg (eds.), Am. Soc. Microbiol. Press, Washington, DC 1990, 335-359.
• [74] Ward J.B., Berkeley R.C.W., The microbial celi surface and adhesion, (in:) Microbial adhesion to surfaces, R.C.W. Berkeley, J.M. Lynch, J. Melling, P.R. Rutter, D. Vincent (eds.), Ellis Horwood, Chichester 1980, 47-66.
• [75] Gannon J.T., Manilal V.B., Alexander M., Relationship between celi surface properties and transport of bacteria through soil, Appl. Environ. Microbiol. 1991, 57, 190-193.
• [76] Hazen T.C., Toranzos G.A., Tropical source waters, (in:) Drinking water microbiologly, G.A. McFeters (ed.), Brock/Springer Series in Contemporary Bioscience 1990, 32-54.
• [77] Hill V.R., Sobsey M.D., Removal of Salmonella and microbial indicators in constructed wet-lands treating swine wastewater, Wat. Sci. Technol. 2001, 44, 215-222.
• [78] Thurston-Enriquez J.A., Henry C.G., Eghball B., Constructed wetlands for the reduction of ma-nure-born fecal indicator and pathogenic microorganisms from dairy cattle wastewater, 9th International Conference on Wetland System for Water Pollution Control, Wetland System, Avignon (France), 26-30th of September 2004, 1, 95-102.
• [79] Deregnier D.L., Cole L., Schupp D.G., Erlandsed S.L., Viability of Giardia cysts suspended in lake, river and tap water, Appl. Environ. Microbiol. 1989, 55, 1223-1229.
• [80] Johnson D.C., Enriquez C.E., Pepper I.L., Daris T.L., Gerba C.P., Rosę J.B., Survival of Giardia, Cryptosporidium, poliovirus and Salmonella in marine waters, Wat. Sci. Technol. 1997, 35, 261-268.
• [81] Filipkowska Z., Sanitarno-biologiczne aspekty oczyszczania ścieków bytowo-gospodarczych na filtrach gruntowo-roślinnych, Wydawnictwo Uniwersytetu Warmińsko-Mazurskiego, Olsztyn 2006, Rozprawy i Monografie no 114, 109 (in Polish).
• [82] Kern J., Treatment of agricultural wastewater in subsurface constructed wetland for the removal of fecal coliform bacteria, [In:] International Workshop Wastewater Hygienisation in Constructed Wetlands, Ponds and Related System. 6-7 November 2003, Leipzig, 14.
• [83] Geldreich E.E., Microbial quality of water supply in distribution system, Lewis Publisher, New York 1996.
• [84] Leong L.Y.C., Colbaugh J.E., Stokes H.W., Leong C.J., Fate of microorganisms in a tertiary treatment system, Wat. Sci. Technol. 1988, 20, 445-447.
• [85] Coombes C, Collett P.J., Use of constructed wetland to protect bathing water quality, Wat. Sci. Technol. 1995,32, 149-158.
• [86] Arias C.A., Cabello A., Brix H., Johansen N.-H., Removal of indicator bacteria from municipal wastewater in an experimental two-stage vertical flow constructed wetland system, Wat. Sci. Technol. 2003,48, 35-41.
• [87] Nokes R.L., Gerba C.P., Karpiscak M.M., Microbial water quality improvement by smali scale on-site subsurface wetland treatment, J. Environ. Sci. Health - Part A Toxic/Hazardous Substances and Eiwironmental Engineering 2003, 38, 1849-1855.
• [88] Olańczuk-Neyman K., Geneja M., Quant B., Dembińska M., Kruczalak K., Kulbat E., Kulik-Kuziemska L, Mikołajski S., Gielert M., Microbiological and biological aspects of the wastewater treatment plant "Wschód" in Gdańsk, Poi. J. Environ. Stud. 2003, 12, 747-757.