RESEARCH ARTICLE Synergistic phytoremediation of wastewater by two aquatic plants (Typha angustifolia and Eichhornia crassipes) and potential as biomass fuel Theeta Sricoth 1 & Weeradej Meeinkuirt 2 & John Pichtel 3 & Puntaree Taeprayoon 2 & Patompong Saengwilai 4,5 Received: 1 August 2017 /Accepted: 20 November 2017 # Springer-Verlag GmbH Germany, part of Springer Nature 2017 Abstract The ability of a mixture of Typha angustifolia and Eichhornia crassipes to remove organics, nutrients, and heavy metals from wastewater from a Thailand fresh market was studied. Changes in physicochemical properties of the wastewater including pH, temperature, chemical oxygen demand, dissolved oxygen, biochemical oxygen demand (BOD), total P, TOC, conductivity, total Kjeldahl nitrogen, NO 3 - -N, NH 3 -N, and metal (Pb, Cd, and Zn) concentrations were monitored. In the aquatic plant (AP) treatment, 100% survival of both species was observed. Dry biomass production and growth rate of T. angustifolia were approximately 3.3× and 2.7× of those for E. crassipes, respectively. The extensive root system of the plants improved water quality as determined by a marked decrease in turbidity in the AP treatment after 7 days. BOD content served as a useful indicator of water quality; BOD declined by 91% over 21 days. Both T. angustifolia and E. crassipes accumulated similar quantities of metals in both roots and shoots. Accumulation of metals was as follows: Zn > Cd > Pb. A study of calorific value and biomass composition revealed that T. angustifolia and E. crassipes possessed similar carbon content (~ 35%), hydrogen content (~ 6%), and gross calorific value. E. crassipes contained up to 16.9% ash and 65.4% moisture. Both species are considered invasive in Thailand; however, they may nonetheless provide practical benefits: In addition to their combined abilities to treat wastewater, T. angustifolia holds potential as an alternative energy source due to its high biomass production. Keywords Synergistic phytoremediation . Typha angustifolia . Eichhornia crassipes . Wastewater . Mesocosm experiment . Calorific value Introduction Wastewater discharged from point sources into freshwater ecosystems results in adverse environmental problems worldwide (Nasir et al. 2015). Untreated wastewater consists of high concentrations of biochemical oxygen demand (BOD), phosphate, and nitrogenous compounds such as am- monia, nitrite, and nitrate (Mook et al. 2012; Lananan et al. 2014). Large inputs of organics may result in excessive growth of macrophytes (e.g., Typha angustifolia, Cyperus iria), filamentous or colonial algae (i.e., Oscillatoria spp., Microcystis aeruginosa), and submerged plants (i.e., Chara spp., Hydrilla verticillata). In freshwater ecosystems, phos- phates and nitrogen are limiting factors for growth of aquatic plants and algal communities (Kanninen et al. 1982; Meeinkuirt et al. 2008; Vaccaro et al. 2009). Many aquatic plants can utilize excess N and P; they are considered low cost and practical vehicles for contaminant remediation (Li et al. 2015). Heavy metals can also be released from the same point source and might accumulate in food chains (Meeinkuirt et al. 2008). Thus, vegetation management should be considered as a contaminant remediation solution for large freshwater resources. Responsible editor: Elena Maestri * Weeradej Meeinkuirt phytoplankton8@gmail.com; weeradej.mee@mahidol.ac.th 1 Navamindradhiraj University, Khao Road, Bangkok 10300, Thailand 2 Mahidol University, Nakhonsawan Campus, Nakhon Sawan 60130, Thailand 3 Natural Resources and Environmental Management, Ball State University, Muncie, IN 47306, USA 4 Department of Biology, Faculty of Science, Mahidol University, Rama VI Road, Bangkok 10400, Thailand 5 Center of Excellence on Environmental Health and Toxicology (EHT), CHE, Ministry of Education, Bangkok, Thailand Environmental Science and Pollution Research https://doi.org/10.1007/s11356-017-0813-5