Horizontal Subsurface Flow Gravel Bed Constructed Wetland with Phragmites Karka in Central India

Abstract

Treatment performance of a field-scale horizontal subsurface (SF) constructed wetland (CW) was evaluated for removal efficiency of BOD, TSS, NH4-N, NO3-N, TKN and P from municipal wastewater emanating from a small community of residential areas in Ujjain, Central India. The SF wetland had a rectangular size and covered an effective surface area of 41.82 m2 with a water retention capacity of 18 m3. The SF medium was composed of a gravel bed supported below on a layer of puddled local clay and overlaid by a thin synthetic liner. CW was planted initially with locally grown grass, Phragmites karka. Plants placed in this rectangular design at the rate of 3 to 4 plants per m2 increased to 6157 plants within ten months producing a biomass of 121 tonnes ha−1. The influent was pretreated before entering the SF system, through two baffles; a grass covered small ditch, followed by a narrow tunnel of packed biofilmed boulders. Removal rates of TSS (48%), TKN (36%), NH4-N (22%) and NO3-N as zero percent were realised. An earthen channel provided initial pretreatment by a land treatment system. Average treatment performance after five months from this SF system recorded removal efficiencies of 78% for NH4-N, TSS; 58-65% for P, BOD and TKN. Effluent dissolved oxygen levels increased to 34% indicating existence of aerobic conditions in the rooted-gravel bed. The SF system overall results established: (a) very cost-effective treatment technology, (b) SF removal efficiency above 50% for BOD, NH4-N, TKN, and P. This SF system presents a unique design consideration compared with the land-intensive Kickuth standard system design.

Treatment performance and microorganism community structure of integrated vertical-flow constructed wetland plots for domestic wastewater

“…The removal mechanisms of phosphorus from wastewater in constructed wetlands were mainly through substrate adsorption, iron exchange, and plant uptake (Billore et al 1999). During the whole experiment, the TP removal efficiency remained relatively steady, and mean TP removal efficiencies (68.01±17.45 %) was similar to the results of Chung et al (2008), Wu et al (2011) and Gikas and Tsihrintzis (2012), but lower than others (Xiong et al 2011;Dong et al 2011;Wang et al 2011).…”

Simulation of constructed wetland performance using the advection diffusion equation

“…It has been observed by many researchers that plug flow conditions are seldom found in the constructed wetland treatment systems. The actual flow condition that occurs in practice can be more accurately modelled as first order kinetics and number of complex mix reactors in series [1][2][3][4][5][6].…”

“…This new developing technology may offer a low cost and low maintenance option for domestic wastewater treatment, which is especially suitable for developing countries [2][3][4].…”

Performance prediction of a constructed wetland wastewater treatment plant

“…The initial sampling started after eight months i.e. April -2002 giving sufficient time for full growth of reeds since wetlands typically require a few months for vegetation and bio-film establishment according to [7]. Sizing of the wetland units was done by using basic relationship for plug flow reactor for the BOD loading as recommended by [8]:…”