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

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/m 2 /d compared to 3.8 g/m 2 /d for water hyacinth.

Utility of constructed wetlands for treatment of hospital effluent and antibiotic resistant bacteria in resource limited settings: A case study in Ujjain, India

“…Constructed wetlands are the water treatment systems that use natural processes involving wetland vegetation, soils, and their associated microbial assemblages to improve the water quality (Barancheshme & Munir, 2018; EPA, 2017). These units have gained attention owing to their easy operation, cost effectiveness, and efficiency (Datta et al, 2016; Fang et al, 2017; Tilak et al, 2017). Successful application of constructed wetlands has been reported for wastewater treatment, heavy metals removal, and antibiotic resistant genes removal using various plant species, such as Canna , Eichhornia , Phragmites , Typha , and Ageratum (Alvarez et al, 2017; Barancheshme & Munir, 2018; Jamwal et al, 2021; Juwarkar et al, 1995; Kumar et al, 2016; Rampuria et al, 2021; Rana et al, 2011; Tilak et al, 2017).…”

Monitoring the Spread of Water Hyacinth (Pontederia crassipes): Challenges and Future Developments

“…Water quality monitoring was performed using sensors for critical parameters like turbidity, temperature and dissolved oxygen while assessing the impact of herbicides used for control of water hyacinth in the Sacramento-San Joaquin delta (Tobias et al, 2019). Monitoring of phosphate concentration too is important as it is closely linked with water hyacinth infestation (Kobayashi et al, 2008;Datta et al, 2016). An IoT based sensor that monitors water quality in real-time was demonstrated by Manimegalai (2020).…”

Constructed wetland for improved wastewater management and increased water use efficiency in resource scarce SAT villages: a case study from Kothapally village, in India

“…The main advantages of both these species are, first, their high growth rate and consistent phytoremediation capacity without much seasonal variation; second, they do not harbor harmful pests or insects and thirdly, both species do not spread beyond the designed vegetated area and do not pose the threat of becoming a 'new weed'. The planting material was collected from the existing constructed wetland in ICRISAT (Supplementary Figure S3), Patancheru campus (Datta et al 2016). Both Typha latifolia and Canna indica covered 40 m 2 area each in the CW, where the former covered 10 m of the length from the inlet side and preceded the Canna indica vegetation which covered the remaining 10 m length of the CW bed.…”

“…The bottles were transported in cold boxes to the ICRISAT Patancheru campus within 2-3 h of sampling for analysis of various parameters during the period of July 2015 to July 2016. Standard methods ( Supplementary Table S1) of wastewater analysis (APHA 2005) were adopted for different physical and chemical parameters (Datta et al 2016). The pathogen removal efficiency of the CW was measured in-terms of Escherichia coli using the most probable number (MPN) method by adopting standard procedures (Kaushal et al 2016).…”