Performance assessment of aquatic macrophytes for treatment of municipal wastewater

Abstract

The objective of the study was to evaluate the performance of three different aquatic macrophytes for treatment of municipal wastewater collected from Taxila (Pakistan). A physical model of treatment plant was constructed and was operated for six experimental runs with each species of macrophyte. Every experimental run consist of thirty days period. Regular monitoring of influent and effluent concentrations were made during each experimental run. For the treatment locally available macrophyte species i.e. water hyacinth, duckweed & water lettuce were selected to use. To evaluate the treatment performance of each macrophyte, BOD5, COD, and Nutrients (Nitrogen and Phosphorus) were monitored in effluent from model at different detention time of every experimental run after ensuring steady state conditions. The average reduction of effluent value of each parameter using water hyacinth were 50.61% for BOD5, 46.38% for COD, 40.34% for Nitrogen and 18.76% for Phosphorus. For duckweed the average removal efficiency for selected parameters were 33.43% for BOD5, 26.37% for COD, 17.59% for Nitrogen and 15.25% for Phosphorus and for Water Lettuce the average removal efficiency were 33.43% for BOD5, 26.37% for COD, 17.59% for Nitrogen and 15.25% for Phosphorus. The mechanisms of pollutant removal in this system include both aerobic and anaerobic microbiological conversions, sorption, sedimentation, volatilization and chemical transformations. The rapid growth of the biomass was measured within first ten days detention time. It was also observed that performance of macrophytes is influenced by variation of pH and Temperature. A pH of 6-9 and Temperature of 15-38°C is most favorable for treatment of wastewater by macrophytes. The option of macrophytes for treatment of Municipal sewage under local environmental conditions can be explored by further verifying the removal efficiency under variation of different environmental conditions. Also this is need of time that macrophyte system should be used for treatment of wastewater because their performance is comparable to conventional wastewater treatment plants and also the system has very low O&M costs.

Wastewater Management Techniques: A Review of Advancement on the Appropriate Wastewater Treatment Principles for Sustainability

“…Additionally, similar results had also been observed for artificial wetlands using emergent macrophytes (Kadlec et al, 2007;Jensen and Gujarathi, 2015;Shah et al, 2015).…”

“…The potential rate of pollutant storage by an aquatic plant is limited by the growth rate and standing crop of biomass per unit area. Water hyacinth, for example, was found to reach a higher standing crop level (Sounders et al, 2012;Outa et al, 2014;Shah et al, 2015).…”

“…Macrophytes take up large amounts of inorganic nutrients (especially N and P) and heavy metals (such as Cd, Cu, Hg and Zn) as a consequence of the Environmental Management and Sustainable Development ISSN 2164-7682 2017 growth requirements and decrease the concentration of algal cells through light shading by the leaf canopy and, possibly, adherence to gelatinous biomass which grows on the roots (Shah et al, 2015). A set up of floating macrophyte systems utilizing water hyacinth and receiving primary sewage effluent in Florida achieved secondary treatment effluent quality with a 6day hydraulic retention time, water depth of 60 cm and hydraulic loading 1860 m 3 /ha.…”

“…In recent years, natural and artificial wetlands and marshes have been adopted in the treatment of raw sewage and partially-treated effluents (Jensen and Gujarathi, 2015;Shah et al, 2015). Natural wetlands are usually unmanaged, whereas artificial systems are specially designed to maximize performance by providing the optimum conditions for emergent macrophyte growth (Vymaza, 2011).…”

Identification and Elucidation of the Designing and Operational Issues of Trickling Filter Systems for Wastewater Treatment

“…The key consideration and hindrance in selection of a suitable treatment system is the cost, energy, trained human resources, system compatibility, and operational complications [15]. The right choice of an appropriate and workable technology is very important because of the [19] Membrane Bioreactor Wastewater COD, MLSS, MLVSS, ammonium nitrogen, phosphate-phosphorus, and TOC [20] Bioremediation (Constructed Wetlands) Municipal wastewater BOD 5 , COD, and nutrients (nitrogen and phosphorus) [21] Constructed Wetlands Domestic wastewater TSS, TDS, SO 4 -2 , PO 4 -3 , NO 3 , NO 2 bacterial counts and fecal pathogens [22] Trickling Biofilter System Municipal wastewater Ammonium nitrogen, BOD 5 , COD, and pathogen [23] Bio-Sorption Synthetic wastewater NH 4 + [24] Anaerobic Reactor and Fenton's Process Textile wastewater Color, COD, and turbidity [25] Constructed Wetlands Industrial wastewater EC, turbidity, COD, TSS, TDS, TS, nitrates, ammonia, phosphates, heavy metals (i.e., Cd, Ni, Hg, and Pb) [26] Bio-Sorption Textile wastewater COD, TDS, TSS, and color [27] Bio-Remediation Textile wastewater. BOD, COD, TOC, and cytotoxicity [28] Advanced Oxidation Processes Municipal wastewater BOD, COD, turbidity, conductivity, pH, and fecal coliform [29] Fixed Biomass and Sand Column Reactor Municipal wastewater Odor, alkalinity, pH, turbidity, BOD 5 , COD, TDS, TSS, EC, PO 4 , SO 4 , NO 3 , NO 2 , and DO [30] Membrane Bioreactor Synthetic wastewater Nutrients [31] Hybrid Constructed Wetland (HCW) Domestic wastewater NO 3 , NO 2 , BOD 5 , COD, SO 4, PO 4 , and pathogenic [32] Fixed Biofilm Reactor Municipal wastewater…”