Water treatment by aquatic ecosystem: Nutrient removal by reservoirs and flooded fields

Abstract

/ Potential use of reservoirs and flooded fields stocked with aquatic plants for reduction of the nutrient levels of organic soil drainage water was evaluated. The treatment systems include 1) a large single reservoir (R1) stocked with waterhyacinth ( Eichhornia crassipes), elodea ( Egeria densa), and cattails ( Typha sp.) in series; 2) three small reservoirs in series with waterhyacinth (R2), elodea (R3), and cattails (R4), grown in independent reservoirs; 3) a control reservoir (R5) with no cultivated plants; 4) a large single flooded field planted to cattails; 5) three small flooded fields in a series planted to cattails; and 6) a flooded field with no cultivated plants. Drainage water was pumped daily (6 hours a day, and 6 days a week) into these systems for a period of 27 months at predetermined constant flow rates. Water samples were collected at the inlet and outlet of each treatment system and analyzed for N and P forms.The series of reservoirs stocked with aquatic plants functioned effectively in the removal of N and P from agricultural drainage water, compared to a single large reservoir. Allowing the water to flow th rough the reservoir stocked with waterhyacinth plants with a residence time of 3.6 days was adequate to remove about 50% of the incoming inorganic N. Allowing the water to flow through a series of two small reservoirs, R2 and R3, with a residence time of 7.3 days was necessary to remove about 60% of the incoming ortho-P. Flooded fields were effective in the removal of inorganic N, but showed poor efficiency in the removal of ortho-P.

Suitability Analysis of Water in an Urban Tropical Lake Using Seasonal Water-Quality Index

“…Seasonally, the concentration of dissolved oxygen was more during summer and least during rainy season. This observation is in conformity with the observation of Reddy et al [15], Ghosh and George [5], and Shashi et al [16].…”

Water quality monitoring of three Lentic water bodies of Ujjain District (M.P.) India

“…Seasonally, the concentration of dissolved oxygen was more during monsoon and least during summer. The observation is in conformity with the observations of Reddy et al (1982), Ghosh and George (1989), Swarnalatha and Narasingarao (1983) and Venkateswarlu (1993). At Undasa wetland Dissolved oxygen values range from 4-6.4 mg/lt ( 2018), pointed out that the water quality in terms of physico-chemical parameters at Pamba River, Kerala is well within the limits and can be used for irrigation, bathing and domestic purposes without any treatment.…”

Historical Changes in Fish Assemblage Composition Following Water Quality Improvement in the Mainstem Trinity River of Texas

“…Reservoirs are known to interrupt nutrient spiralling in riverine systems through the framework of the serial discontinuity concept (Ward and Stanford, 1983). Under this framework, the creation of a large lentic reservoir upstream of the dam at Lake Livingston acted as a resetting mechanism, so that nutrients from the inflowing Trinity River became assimilated in the lake and outflows trended towards lower nutrient concentrations (Reddy et al, 1982;Groeger and Kimmel, 1984). Other pollutants such as heavy metals (lead) and dichlorodiphenyltrichloroethane have settled in the sediments of Lake Livingston since construction in 1969 (Van Metre and Callender, 1996).…”