International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056 Volume: 06 Issue: 03 | Mar 2019 www.irjet.net p-ISSN: 2395-0072 © 2019, IRJET | Impact Factor value: 7.211 | ISO 9001:2008 Certified Journal | Page 964 GREY WATER TREATMENT BY WATER HYACINTH-A REVIEW Shivangi Singh 1 , Nusrat Ali 2 1 (Student, Civil Engineering Department, Integral University, Lucknow, U.P, India) 2 (Assistant Professor, Civil Engineering Department, Integral University, Lucknow, U.P, India) ---------------------------------------------------------------------***---------------------------------------------------------------------- Abstract - Aquatic plants for the treatment of domestic wastewater have been used by several researchers. All techniques are reported to be cost effective compared to other methods. Various contaminants like total suspended solids, dissolved solids, hardness, biochemical oxygen demand, chemical oxygen demand, dissolved oxygen, nitrogen, phosphorous, heavy metals, and other contaminants have been minimized using aquatic plants like water hyacinth, hydrilla etc. In this paper role of all plant species, origin and their occurrence, ecological factors and their efficiency in reduction of different water contaminants have been presented. Key Words: Domestic Wastewater, Water Hyacinth, Aquatic Plants, Hydrilla 1. INTRODUCTION Aquatic plant system has been accounted as one of the processes for wastewater recovery, reuse and recycling. The main purposes for using this system have focused on waste stabilization and nutrient removal. The removal mechanism are physical sedimentation and bacterial metabolic activity as in the conventional activated sludge and trickling filter (USEPA, 1991). Plant assimilation of nutrients and their subsequent harvesting are another mechanism for pollutant removal. Minimum cost and easy maintenance make the aquatic plant system attractive to use. Thus constructed ponds with aquatic plants are increasingly applied as a viable treatment for domestic wastewater. However, there are some constraints with using aquatic plants such as the requirement for large area of land, the reliability for pathogen destruction, and the types and end-uses of aquatic plants. Water hyacinth (Eichhornia crassipes) treatment systems are generally known in tropical area. The system with WH can operate at higher loading rates. Their end-use products can be utilized for organic fertilizer. Dry WH petioles can be woven into baskets and purse (Polprasert, 1996). The degree of purification of wastewater within a hyacinth lagoon depends not only on the capacity of the plants to assimilate nutrients, but also on their potential to alter the wastewater environment to enhance removal of organic matter through biochemical processes. Water hyacinth lagoons function as horizontal trickling filters in which submersed plant roots provide physical support for a thick bacterial biofilm, which actively degrades organic matter (Stowell et al. 1981). They are considered to combine the physical process of filtration with fixed–film and suspended growth biological conversion processes. The micro- organisms degrade organic matter, producing metabolites, which they and the plants utilize along with nitrogen, phosphorus and other minerals as a food source. The system differs from other more conventional fixed-film systems in that the attachment medium is biologically active. 2. LITERATURE REVIEW Thongchai Kanabkaew (2004) investigates that the enhanced removal efficiency of unconventional plants for aquatic treatment system as post treatment. Lotus (Nelumbo nucifera) and hydrilla (Hydrilla verticillata) were planted with one control unit. Influents and effluents were analysed for pH, SS, BOD5, TKN, NH3 -N, NO2 - -N, NO3 - -N, TP and Coliform bacteria twice a week. The results showed that ponds with aquatic plants were superior to those who don’t have aquatic plants. The system with lotus showed the good removal efficiency for wastewater treatment. For the system with hydrilla verticillata, it was found that pH and SS of the effluent were high. It might not be best to use hydrilla for effluent polishing. Rajendra B. Magar (2017) defines that the roots of Water hyacinths (WH) naturally absorb pollutants including lead, mercury, and strontium90, as well as some organic compounds which are carcinogenic and have concentrations of approximately 10,000 time that is present as in generically found water. This study attempts to evaluate the effect of WH in two different type of sewer or drainage line, one from water closet and another from bath or shower room. Further, the reading for various parameters like Potential of hydrogen (pH), Turbidity, Chemical oxygen demand (COD), chloride and colour has been periodically taken every 24 hrs for 5 days. The effect of WH has resulted in significant decrease in turbidity and due to which the reduction of flocs and reduction in organic matters in water have been observed. R. Sooknaah (2000) Presence of aquatic plants in natural or constructed wetlands not only reduces the concentration of problematic nutrients from the wastewater, but also alters the physico-chemical environment of the water, rhizosphere and underlying sediment (Reddy & Patrick, 1984). In addition to plant assimilation of nutrients, changes in the environment of the water also help in reducing the pollutant level of the wastewater through biochemical processes brought about by micro-organisms. This paper gives a