Author Details

Water scarcity and elevated potential in wastewater treatment in the last decades raise attention towards constructed wetlands (CWs). The present study was carried out to evaluate the efficacy of CW for faecal coliform (FC) expulsion and to isolate and characterize the microbial communities. Significant differences were observed between influent and effluent microbial counts of vegetated and control cells (without vegetation) of wetland. FC reduction ranged from 64% to 81%; however, total bacterial, fungal and actinomycetes average poll ranged from 66.67 × 10⁵ cfu/g to 142.67 × 10⁵ cfu/g, 1.67 × 10² cfu/g to 10.33 × 10² cfu/g and 16.00 × 10³ cfu/g to 53.33 × 10³ cfu/g respectively, isolated from vegetated and control cells. Results further indicated that bacteria were most abundant, followed by actinomycetes, whereas the number of fungi was least among three groups of microbes, which could be attributed to wide tolerance to the properties of CW. Removal of FC was less apparent initially compared to the later stages of operation, which is of concern for long-term efficiency and stability of wetland. Also, diversity of identified bacterial strains is beneficial for growth and yield enhancement of agriculture crops. The results also demonstrate that CWs are the key habitats for bioactive actinomycetes with paramount medical, scientific and economic potential significance globally in general and developing countries like India in particular. Overall, backwash imparts the baseline compilation of CWs for its management for sustainable agriculture.

Keywords

Actinomycetes, Bacteria, Constructed Wetland, Faecal Coliform, MPN.

Full Text

References

Green, B., Constructed wetlands are big in small communities. Water. Environ. Technol., 1994, 65, 51–55.

Leonard, S. M., Analysis of residential subsurface flow constructed wetland performance in northern Alabama. Small Flows Q, 2000, 1, 34–39.

Negm, M. S., Nagy, N. M. and Abdel-Rasik, M. H., Sewage characteristics and per capita loads in Ismailia City, Second Middle East Conference, Cairo Egyptian Wastewater Management, 1995.

Denny, P., Implementation of constructed wetlands in developing countries. Water Sci. Technol., 1997, 35, 27–34.

Kayranli, B., Scholz, M., Mustafa, A., Hofmann, O. and Harrington, R., Performance evaluation of integrated constructed wetlands treating domestic wastewater. Water Air Soil Pollut., 2010, 210, 435–451.

Aguilar, J. R. M., Cabriales, J. J. P. and Vega, M. M., Identification and characterization of sulfur-oxidizing bacteria in an artificial wetland that treats wastewater from a tannery. Int. J. Phytoremediat., 2008, 10, 359–370.

Brix, H., Do macrophytes play a role in constructed treatment wetlands? Water Sci. Technol., 1997, 35, 11–17.

Gagnon, V., Chazarenc, F., Comeau, Y. and Brisson, J., Influence of macrophyte species on microbial density and activity in constructed wetlands. Water Sci. Technol., 2007, 56, 249–254.

Munch, Ch., Neu, T., Kuschk, P. and Roske, I., The ischolar_main surface as the definitive detail for microbial transformation processes in constructed wetlands – a biofilm characteristic. Water Sci. Technol., 2007, 56, 271–276.

Stottmeister, U. et al., Effects of plants and microorganisms in constructed wetlands for wastewater treatment. Biotechnol. Adv., 2003, 22, 93–117.

APHA, Standard methods for examination of water and wastewater. American Public Health Association, New York, 1989.

Kaushal, M., Kaushal, R. and Mandyal, P., Impact of integrated nutrient management systems on cauliflower (Brassicaoleracea var. botrytis) yield and soil nutrient status. Indian J. Agric. Sci., 2013, 83, 1013–1016.

Bergey’s Manual of Systematic Bacteriology, The Williams and Wilkins, Co., Baltimore, 1986, 1st edn, p. 442.

Vymazal, J., The use constructed wetlands with horizontal subsurface flow for various types of wastewater. Ecol. Eng., 2009, 35, 1–17.

Vymazal, J., Constructed wetlands for wastewater treatment. Water, 2010, 2, 530–549.

Truu, J., Nurk, K., Juhanson, J. and Mander, U., Variation of microbiological parameters within planted soil filter for domestic wastewater treatment. J. Environ. Sci. Heal. A, 2005, 40, 1191–1200.

Garcia, M. and Becares, E., Bacterial removal in three pilot-scale wastewater treatment systems for rural areas. Water Sci. Technol., 1997, 35, 197–200.

Gersberg, R. M., Lyon, S. R., Brenner, R. and Elkins, B. V., Fate of viruses in artificial wetlands. Appl. Environ. Microbiol., 1987, 53, 731–736.

Hatano, K., Trettin, C. C., House, C. H. and Wollum II, A. G., Microbial populations and decomposition activity in three subsurface flow constructed wetlands. In Constructed Wetlands for Water Quality Improvement (ed. Moshiri, G. A.), Lewis Publishers, Boca Raton, Florida, 1993, pp. 541–547.

Kim, T. K. and Garson, M. J., Marine Actinomycetes related to the ‘Salinospora’ group from the Great Barrier Reef sponge Pseudoceratina clavata. Environ. Microbiol., 2005, 7, 509–518.

Ningthoujam, D. S., Sanasam, S. and Nimaichand, S., Screening of Actinomycete isolates from niche habitats in Manipur for antibiotic activity. Am. J. Biochem. Biotechnol., 2009, 5, 221–225.

Collins, B., McArthur, J. V. and Sharitz, R. R., Plant effects on microbial assemblages and remediation of acidic coal pile runoff in mesocosm treatment wetlands. Ecol. Eng., 2004, 23, 107–115.

Weber, K. P., Gehder, M. and Legge, R. L., Assessment of changes in the microbial community of constructed wetlands mesocosms in response to acid mine drainage exposure. Water Res., 2008, 42, 180–188.

Field Scale Evaluation of Seasonal Wastewater Treatment Efficiencies of Free Surface-Constructed Wetlands in ICRISAT, India

Abstract Views :324 | PDF Views:94

Authors

A. Datta ¹, S. P. Wani ¹, M. D. Patil ¹, A. S. Tilak ¹

Affiliations
1 International Crops Research Institute for the Semi-Arid Tropics, Patancheru 502 324, IN

Source

Current Science, Vol 110, No 9 (2016), Pagination: 1756-1763

Abstract

The disparity between volume of wastewater generated and treated has resulted in severe water pollution and eutrophication of the water bodies in most Indian cities. Constructed wetlands (CWs) present a low-cost wastewater treatment option; however, field scale studies with real life wastewater are limited. Eichhornia crassipes (water hyacinth), Typha latifolia (Typha) and Pistia stratiotes (water lettuce) grow abundantly in eutrophicated water bodies, and are known for their nutrient uptake ability. In the present study, the wastewater of a nearby urban residential colony was treated by two-field scale free water surface CWs operating under identical hydraulic loading. The first treatment cells, in each of these two CWs were vegetated with Typha. The second treatment cells were vegetated with water hyacinth (CW-1) in one of the CWs and with water lettuce (CW-2) in the other. Wastewater treatment efficiencies of these free water surface CWs were evaluated, in terms of the removal efficiencies for key parameters, viz. chemical oxygen demand (COD), ammoniacal and nitrate nitrogen, phosphate, sulphate and total suspended solids (TSS). The CW-1 showed greater seasonal variation in performance. A steady removal efficiency of 35-40% was observed for ammoniacal nitrogen in both the free water surface CWs throughout the year, though removal efficiency of nitrate nitrogen reduced significantly during the winter. Plant sample analysis showed that the N, P and K uptake capacities of water lettuce were 1.53, 1.55 and 1.34 times higher than that of water hyacinth, for identical wastewater loading. The dry weight of the harvested biomass for water lettuce, during summer months, was much higher at 5.63 g/m²/d compared to 3.8 g/m²/d for water hyacinth.

Keywords

Constructed Wetland, Domestic Wastewater, Field Scale, Free Water Surface, Macrophytes.

Full Text

References

Kaur, R., Wani, S. P., Singh, A. K. and Lal, K., Wastewater production, treatment and use in India, Country Report India, 2012.

Sato, T., Qadir, M., Yamamoto, S., Endo, T. and Zahoor, A., Global, regional, and country level need for data on wastewater generation, treatment, and use. Agric. Water Manage., 2013, 13, 1–13.

Sharma, G. and Urmila, B., Performance analysis of vertical upflow constructed wetlands for secondary treated effluent. APCBEE Procedia, 2014, 10, 110–114.

Lu, Q., Evaluation of aquatic plants for phytoremediation of eutrophic stormwaters, Ph D thesis, University of Florida, Florida, 2009.

John, R., Ahmad, P., Gadgil, K. and Sharma, S., Effect of cadmium and lead on growth, biochemical parameters and uptake in Lemna polyrrhiza L. Plant Soil Environ., 2008, 54, 262–270.

Maine, M. A., Sune, N. L. and Lagger, S. C., Chromium bioaccumulation: Comparison of the capacity of two floating aquatic macrophytes. Water Res., 2004, 38, 1494–1501.

Mishra, V. K., Upadhyay, A. R., Pandey, S. K. and Tripathi, B. D., Concentrations of heavy metals and aquatic macrophytes of Govind Ballabh Pant Sagar an anthropogenic lake affected by coal mining effluent. Environ. Monit. Assess., 2008, 141, 49–58.

Lissy, A. M. P. N. and Madhu, B. G., Removal of heavy metals from waste water using water hyacinth. In Proceedings of the International Conference on Advances in Civil Engineering, 2010, pp. 42–47.

USEPA, 1988, Design Manual – Constructed wetlands and aquatic systems for municipal wastewater treatment, United States Environmental Protection Agency, Report no. EPA/625/1-88/022, Office of Research and Development, Cincinnati, OH, 83.

Reddy, K. R., Agami, M., D’Angelo, E. M. and Tucker, J. C., Influence of potassium supply on growth and nutrient storage by water hyacinth. Bioresource Technol., 1991, 37, 79–84.

Sato, M. and Kondo, S., Biomass production of water hyacinth and its ability to remove inorganic minerals from water. I. Effect of the concentration of culture solution on the rates of plant growth and nutrient uptake. Jap. J. Ecol., 1981, 31, 257–267.

Delgado, M., Bigeriego, M., Walter, I. and Guardiola, E., Optimization of conditions for the growth of water hyacinth in biological treatment. Rev. Int. Contam. Ambient., 1994, 10, 63–68.

DeBusk, T. A., Williams, L. D. and Ryther, J. H., Removal of nitrogen and phosphorus from wastewater in a water hyacinth based treatment system. J. Environ. Qual., 1983, 12, 257–262.

Snow, A. M. and Ghaly, A. E., A comparative study of the purification of aquaculture wastewater using water hyacinth, water lettuce and parrot’s feather. Am. J. Appl. Sci., 2008, 5, 440–453.

Adeniran, E., The efficiency of water hyacinth (Eichhornia crassipes) in the treatment of domestic sewage in an African University, Annual Water Resources Conference, lbuquerque, New Mexico, 2011.

Ayyasamy, P. M., Rajakumar, S., Sathishkumar, M., Swaminathan, K., Shanthi, K., Lakshmanaperumalsamy, P. and Lee, S., Nitrate removal from synthetic medium and groundwater with aquatic macrophytes. Desalination, 2009, 242, 286–296.

Reddy, K. R., Campbell, K. L., Graetz, D. A. and Portier, K. M., Use of biological filters for treating agricultural drainage effluents. J. Environ. Qual., 1982, 11, 591–595.

Sheffield, C. W., Water hyacinth for nutrient removal. Hyacinth Cont. J., 1967, 6, 27–30.

Ornes, W. H. and Sutton, D. L., Removal of phosphorus from static sewage effluent by water hyacinth. Hyacinth Cont. J., 1975, 13, 56–61.

Bramwell, S. A. and Devi Prasad, P. V., Performance of a small aquatic plant wastewater treatment system under Caribbean conditions. J. Environ. Manage., 1995, 44, 213–220.

Kasselmann, C., Aquarium Plants, Ulmer GMBH & Co, Stuttgart, 1999, 2nd edn; ISBN-10: 3800174545.

Aoi, T. and Ohba, E., Rates of nutrient removal and growth of the water lettuce (Pistia stratiotes). In Proceedings of the 6th International Conference on the Conservation and Management of Lakes, Kasumigaura, 1995.

Fonkou, T., Agendia, P., Kengne, I., Akoa, A. and Nya, J., Potentials of water lettuce (Pistia stratiotes) in domestic sewage treatment with macrophytic lagoon systems in Cameroon. In Proceedings of International Symposium on Environmental Pollution Control and Waste Management, Tunis, 2002, pp. 709–714.

Mitchell, D. S., Surface-floating aquatic macrophytes. In The Ecology and Management of African Wetland Vegetation (ed. Denny, P.), Dr W. Junk Publishers, Dordrecht, 1985, pp. 109–124.

O’Brien, W. J., Use of aquatic macrophytes for wastewater treatment. Amer. Soc. Civ. Engineers, 1981, 107, 681–698.

Makhanu, K. S., Impact of water hyacinth in Lake Victoria. In Water and Sanitation for all: Partnerships and Innovations, 23rd Water Engineering and Development Centre Conference, Durban, South Africa.

Karpiscak, M. M., Foster, K. E., Hopf, S. B., Bancroft, J. M. and Warshall, P. J., Using water hyacinth to treat municipal wastewater in the desert southwest. Water Resour. Bull., 1994, 30, 219–227.

El-Gendy, A. S., Biswas, N. and Bewtra, J. K., A floating aquatic system employing water hyacinth for municipal landfill leachate treatment: Effect of leachate characteristics on the plant growth. J. Environ. Eng. Sci., 2005, 4, 227–240.

Reddy, K. R. and Sutton, D. L., Water hyacinths for water quality improvement and biomass production. J. Environ. Qual., 1984, 13, 1–9.

Aoi, T. and Hayashi, T., Nutrient removal by water lettuce (Pistia stratiotes). Water Sci. Technol., 1996, 34, 407–412.

Awuah, E., Oppong-Peprah, M., Lubberding, H. J. and Gijzen, H. J., Comparative performance studies of water lettuce, duckweed and algal-based stabilization ponds using low-strength sewage. J. Toxicol. Environ. Health – Part A, 2004, 67, 1727–1739.

Ingersoll, T. and Baker, L. A., Nitrate removal in wetland microcosms. Water Res., 1998, 32, 677–684.

Sahrawat, K. L., Ravi, K. G. and Murthy, K. V. S., Sulphuric acidselenium digestion for multi-element analysis in a single plant digest. Commun. Soil Sci. Plant Anal., 2002, 33, 3757–3765.

Sahrawat, K. L., Ravi, K. G. and Rao, J. K., Evaluation of triacid and dry ashing procedures for determining potassium, calcium, magnesium, iron, zinc, manganese, and copper in plant materials. Commun. Soil Sci. Plant Anal., 2002, 33, 95–102.

Mills, H. A. and Jones Jr, J. B., Plant Analysis Handbook II: A Practical Sampling, Preparation, Analysis and Interpretation guide, Micro-Macro Publishing, Athens, 1996.

http://www.yr.no/place/india/Andhra_Pradesh/Meda/statistics.html

Holt, J. G., Hendricks, B. D. and Breed, R. S. (eds), Bergey's Manual of Determinative Bacteriology, Lippincott Williams and Wilkins, USA, 1993, 9th edn; ISBN0-683-00603-7.

Grundmann, G. L., Neyra, M. and Normand, P., High-resolution phylogenetic analysis of NO2 – oxidizing nitrobacter species using the rrs-rrl IGS sequence and rrl genes. Int. J. Syst. Evol. Microbiol., 2000, 50, 1893–8.PMID11034501.

George, M. G., Bergey’s Manual of Systematic Bacteriology. 2. Auflage, Springer, New York, 2005; ISBN 0-387-24145-0.

Evaluating Wastewater Treatment Efficiency of Two Field Scale Subsurface Flow Constructed Wetlands

Abstract Views :287 | PDF Views:105

Authors

A. S. Tilak ¹, S. P. Wani ¹, M. D. Patil ¹, A. Datta ¹

Affiliations
1 International Crops Research Institute for the Semi-Arid Tropics, Patancheru 502 324, IN

Source

Current Science, Vol 110, No 9 (2016), Pagination: 1764-1772

Abstract

Constructed wetlands (CWs) are human-made systems designed to treat a variety of industrial, domestic and agricultural wastewaters. We study here the efficiency of domestic wastewater treatment by two field scale subsurface flow CWs under different hydraulic loading rates (HLRs). Each CW had inlet and outlet chamber for wastewater collection with Pistia stratiotes (water lettuce), two treatment sections consisting of sand and gravel media and four plant species Typha latifolia (Broadleaf cattail) and Cymbopogon citratus (lemon grass - first CW) and (Pennisetum purpureum schum and Pennisetum americanum L (Hybrid napier) and Urochloa mutica (Paragrass - second CW). The wastewater source was from a residential urban colony. The HLRs for the first and second CW for a three-month period averaged 4.45 cm/day and 5.77 cm/day respectively. The CW was monitored for quality of wastewater inflows and outflows and nutrient accumulation in plants and sand media. Results showed that the chemical oxygen demand (COD), total suspended solids (TSS), total nitrogen and total phosphate removals in the first and second CW over a three-month period averaged 42%, 74%, 39% and 41% and 34%, 82%, 14% and 35% respectively. Both the CWs showed similar rates of TSS removal irrespective of the type of wetland plant species. Over the three-month period, average COD, total nitrogen and the phosphate removals were greater in the first CW compared to the second CW. These results confirm the efficacy of field scale subsurface flow CWs to improve the quality of domestic wastewater in rural communities of developing countries like India.

Keywords

Constructed Wetlands, Domestic Wastewater, Field Scale, Subsurface Flow.

Full Text

References

Vymazal, J., Horizontal sub-surface flow and hybrid constructed wetlands systems for wastewater treatment. Ecol. Eng., 2005, 25, 478–490.

Scholes, L. N. L., Shutes, R. B. E., Revitt, D. M., Purchase, D. and Forshaw, M., The removal of urban pollutants by constructed wetlands during wet weather. Water Sci Technol., 1999, 40, 33, 333–340.

Shelef, O., Gross, A. and Rachmilevitch, S., Role of plants in a constructed wetland: current and new perspectives. Water, 2013, 5, 405–419.

Stefanakis, A., Akratos, C. and Tsihrintzis, S., Vertical Flow Constructed Wetlands: Eco-engineering Systems for Wastewater and Sludge Treatment, Elsevier Science Publishing Co Inc, 2015, 1st edn.

Brix, H., Do macrophytes play a role in constructed treatment wetlands? Water Sci. Technol., 1997, 35, 11–17.

Cooke, J. G., Nutrient transformations in a natural wetland receiving sewage effluent and the implications for waste treatment. Water Sci. Technol., 1994, 29, 209–217.

Tanner, C. C., Clayton, J. S. and Upsdell, M. P., Effect of loading rate and planting on treatment of dairy farm wastewaters in constructed wetlands – I. Removal of oxygen demand, suspended solids and faecal coliforms. Water Resources, 1995, 29, 17–26.

Vymazal, J., Removal of nutrients in various types of constructed wetlands. Sci. Total Environ., 2007, 380, 48–65.

Klomjek, P. and Nitisoravut, S., Constructed treatment wetland: a study of eight plant species. Chemosphere, 2005, 58, 585–593.

United States Environmental Protection Agency (USEPA), Manual for Constructed Wetlands Treatment of Municipal Wastewaters, EPA/625/R-99/010, Cincinnati, USEPA, 2000.

APHA, Standard Methods for the Examination of Water and Wastewater, 4500-NH3 F, American Public Health Association (APHA), Washington, DC, 2005, 21st edition.

APHA, Standard Methods for the Examination of Water and Wastewater, 4500-NO3 B, American Public Health Association, Washington, DC, 2005, 21st edition.

APHA, Standard Methods for the Examination of Water and Wastewater, 4500-P D, American Public Health Association, Washington, DC, 2005, 21st edition.

APHA, Standard Methods for the Examination of Water and Wastewater, 5220-C, American Public Health Association, Washington, DC, 2005, 21st edition.

APHA, Standard Methods for the Examination of Water and Wastewater, 2540-D, American Public Health Association, Washington, DC, 2005, 21st edition.

Dalal, R. C., Sahrawat, K. L. and Myers, R. J. K., Inclusion of nitrate in the Kjeldahl nitrogen determination of soils and plant materials using sodium thiosulphate. Commun. Soil Sci. Plant Anal., 1984, 15, 1453–1461.

Olsen, S. R. and Sommers, L. E., Phosphorus. In Methods of Soil Analysis (eds Page, A. L., Miller, R. H. and Keeney, D. R.), American Society of Agronomy and Soil Science Society of America, Madison, Wisconsin, USA, 1982, pp. 403–430, part II, 2nd edn.

Tandon, H. L. S., Cescas, M. P. and Tyner, E. H., An acid free vanadate–molybdate reagent for the determination of total phosphorus in soils. Soil Sci. Soc. Am. Proc., 1962, 32, 48–51.

Thomas, G. W., Exchangeable cations. In Methods of Soil Analysis (eds Page, A. L., Miller, R. H. and Keeney, D. R.), American Society of Agronomy and Soil Science Society of America, Madison, Wisconsin, USA, 1982, pp. 159–165, Part II, 2nd edition.

Sahrawat, K. L., Kumar G. R. and. Murthy, K. V. S., Sulfuric acid–selenium digestion for multi-element analysis in a single plant digest. Commun. Soil Sci. Plant Anal., 2002, 33, 3757–3765.

Matthew, S. W., Fowles, T. O. and Palmer, L. T., A cost-effective acid digestion method using closed polypropylene tubes for inductively coupled optical emission spectrometry (ICP-OES) analysis of plant essential elements. Anal. Methods, 2011, 3, 2854–2863.

United States Environmental Protection Agency (USEPA), Office of wastewater management, Report to congress: clean water needs survey, 2000, 2004.

Merlin, G., Pajean, J. L. and Lissolo, T., Performances of constructed wetlands for municipal wastewater treatment in rural mountainous area. Hydrobiologia, 2002, 469, 87–98.

Thomas, P. R., Glover, P. and Kalaroopan, T., An evaluation of pollutant removal from secondary treated sewage effluent using a constructed wetland system. Water Sci. Technol., 1995, 32, 87–93.

Kaseva, M. E., Performance of a sub-surface flow constructed wetland in polishing pre-treated wastewater-a tropical case study. Water Res., 2004, 38, 681–687.

Lee, C. Y., Lee, C. C., Lee, F. Y., Tseng, S. K. and Liao, C. J., Performance of subsurface flow constructed wetland taking pretreated swine effluent under heavy loads. Bio-resource Technol., 2004, 92, 173–179.

Schulz, C., Gelbrecht, J. and Rennert, B., Treatment of rainbow trout farm effluents in constructed wetland with emergent plants and subsurface horizontal water flow. Aquaculture, 2003, 217, 207–221.

Gale, P. M., Reddy, K. R. and Graetz, D. A., Nitrogen removal from reclaimed water applied to constructed and natural wetland microcosms. Water Environ. Res., 1993, 65, 162–168.

Brix, H., Arias, C. A. and Del Bubba, M., Media selection for sustainable phosphorus removal in subsurface flow constructed wetlands. Water Sci. Technol., 2001, 44, 47–54.

Polomski, R. F., Taylor, M. D., Bielenberg, D. G., Bridges, W. C., Klaine, S. J. and Whitwell, T., Nitrogen and phosphorus remediation by three floating aquatic macrophytes in greenhouse-based laboratory-scale subsurface constructed wetlands. Water, Air, Soil Pollut., 2009, 197, 223–232.

Zingelwa, N. and Wooldridge, J., Tolerance of macrophytes and grasses to sodium and chemical oxygen demand in winery wastewater. South Afr. J. Enol. Vitic., 2009, 30, 117–123.

Costa, J. F., Martins, W. L. P., Martin, S. and Sperling, M., Role of vegetation (Typha latifolia) on nutrient removal in a horizontal subsurface-flow constructed wetland treating UASB reactor– trickling filter effluent. Water Sci. Technol., 2015, 71, 1004–1010; doi: 10.2166/wst.2015.055.

Kadlec, R. H., Comparison of free water and horizontal subsurface treatment wetlands. Ecol. Eng., 2009, 35, 159–174.

Metcalf and Eddy Inc., Wastewater Engineering: Treatment, Disposal and Reuse (eds Tchobanoglous, G. and Burton, F. L.), McGraw-Hill, New York, 1991, 3rd edn.

Reddy, K. R. and Patrick, W. H., Nitrogen transformations and loss in flooded soils and sediments. CRC Crit. Rev. Environ. Control., 1984, 13, 273–309.

Kadlec, R. H. and Knight, R. L., Treatment Wetlands, Lewis Publishers, Boca Raton, USA, 1996.

Paul, E. A. and Clark, F. E., Soil Microbiology and Biochemistry, Academic Press, San Diego, California, 1996.

Dunne, E. J. and Reddy, K. R., Phosphorus biogeochemistry of wetlands in agricultural watersheds. In Nutrient Management in Agricultural Watersheds: A Wetlands Solution (eds Dunne, E. J., Reddy, K. R. and Carton, O. T.), Academic Publishers, Wageningen, 2005, pp. 105–119.

Username
Password
Remember me