Dynamic remediation test of polluted river water by Eco-tank system

Abstract

Dynamic remediation of river water polluted by domestic sewage using an aquatic plants bed-based Eco-tank system was investigated. Over a period of 18 days, the test demonstrated that average effluent concentrations of chemical oxygen demand (COD), ammonium nitrogen (NH4(+)-N) and total phosphorus (TP) were as low as 17.28, 0.23 and 0.03 mg/L, respectively, under the hydraulic retention time (HRT) of 8.7 d. The average removal efficiencies in terms of COD, NH4(+)-N and TP could reach 71.95, 97.96 and 97.84%, respectively. The loss of both NH4(+)-N and TP was mainly ascribed to the uptake by plants. Hydrocotyle leucocephala was effective in promoting the dissolved oxygen (DO) level, while Pistia stratiotes with numerous fibrous roots was significantly effective for the removal of organic compounds. The net photosynthetic rate, stomatal conductance, transpiration rate and biomass accumulation rate of Myriophyllum aquaticum were the highest among all tested plants. Thus, the Eco-tank system could be considered as an alternative approach for the in situ remediation of polluted river water, especially nutrient-laden river water.

Removal of Selected Pollutants in Household Effluent by Solidified Coal Ash and Water Lettuce

“…In the water lettuce treatments, all of the concentrations of T-N, T-P, and TOC decreased quickly and reached approximately 2%, 10% and 25% of the initial concentration for T-P, T-N, and TOC, respectively. These results suggest the significant enhancement for the wastewater treatment plant with relatively low cost, as reported by other researchers (Zimmel et al, 2008;Lu et al, 2010;Xiao et al, 2013) For the PPCPs, most of acetaminophen and triclosan was removed in the activated sludge and only less than 5% remained at the beginning of the water lettuce experiment except for triclosan in February 2010. The concentrations of these two PPCPs became as low as the lower limit of quantification (LOQ: 6.6 μg/L for triclosan and 2.1 μg/L for acetaminophen) once the water lettuce treatment was started, which suggests the potential of as high as 98% removal of these PPCPs in the combination of the activated sludge process and the retention in the pond with water lettuce.…”

“…This floating macrophyte covers the surface water and becomes a threat for native aquatic organisms as an "invasive species" in Japan. On the other hand, water lettuce has been known to effectively remove pollutants such as nutrients (Ayyasamy et al, 2009;Lu et al, 2010;Akinbile and Yusoff, 2012;Rawat et al, 2012;Xiao et al, 2013), metals (Mishra and Tripathi, 2008;Mufarrege et al, 2010;Lu et al, 2011;Vesely et al, 2011Vesely et al, , 2012 and pesticides (Prasertsup and Ariyakanon, 2011). The phytoremediation potential of these plants were evaluated in the laboratory scale (Zimmels et al, 2008), in the pilot-plant scale (Polomski et al, 2009) or field scale (Nahlik and Mitsch, 2006).…”

A novel submerged Rotala rotundifolia, its growth characteristics and remediation potential for eutrophic waters

“…Eutrophication resulted from excessive discharge of nutrients is still the most prevalent water problem in many countries all over the world 1 . Major nutrient sources include agricultural runoff 2 , domestic sewage 3 , industrial effluents 4 and atmospheric dry and wet deposition 5–7 . High nutrient loads in water may cause rapid growth of algae, consequently, reduce or eliminate dissolved oxygen (DO) in the water, leading to death of large numbers of fish 8,9 .…”

Dual Purpose System for Water Treatment From a Polluted River and the Production of Pistia stratiotes Biomass Within a Biorefinery

“…Its effectiveness for removing nutrients [2,[7][8][9][10] and metals [11][12][13] has been demonstrated in the treatment of different types of wastewaters. It has been also used to treat domestic wastewater [14][15][16]. The biomass produced during the wastewater treatment has been used as the added value products, such as fish or cattle food [17], fodder [18], and biogas feed [19].…”

“…The water from an urban river polluted with untreated domestic wastewater could be effectively used as a nutrient source for P. stratiotes growth and this application has not been reported so far. There is only one report using P. stratiotes , in which domestic wastewater diluted with tap water 1:2 (v/v) was called “polluted river water” and experiments were performed only for 18 days . The harvested biomass could be processed through anaerobic digestion.…”