Benefits in the Tilapia Growth, by Vetiver Grass in an Aquaponics System

Tilapia aquaculture has growing vertiginously in the world, reaching 7.02 million tons in 2020. In Mexico, the same year reached 72.6 thousand tons. This production values have increased environmental impact and production costs. In Mexico there is a pre-Hispanic aquaponics system, where people culture corn, bean fishes and other organisms. Taken this system as basis, the aim this work was demonstrate the benefits in tilapia aquaculture, by Vetiver grass. Three mini-ponds make up by tilapia juveniles and Vetiver in aquaponics system, and one mini-pond without Vetiver, were cultured during ten weeks. The ammonia, nitrates, dissolved O2, pH etc., and also tilapia weights were recorded along experiment. Results indicated that, ammonia decreased, nitrate increased and tilapia weight increased significantly in mini-ponds with Vetiver than without Vetiver. A von Bertalanffy simplified model was used to calculate time required for tilapias reached 500 g (commercial size) with Vetiver and without Vetiver; it was 48.6 and 54.4 weeks respectively. An extrapolation to commercial tilapia aquaculture, will decreased production cost, due to lower amount of feed and water in tilapia hatcheries; also, a lower environmental impact by wastes discharged to coastal ecosystems, e.g., the amount of ammonia produced in mini-ponds with Vetiver was 4.56 times less than mini-pond without Vitier at week ten. Moreover, tilapia culture with Vetiver, have an aggregated value, because Vetiver is used in perfumes production, reaching 45.2 billons US dollars in 2020.

EFFECT OF ROOT OF VETIVER GRASS AND THE SHEAR STRENGTH OF ROOT IN PERMEATED SOIL

Recently, bioengineering has been approached as one of the slope stabilizations techniques as it is inexpensive compared to the mechanical stabilization technique. However, numbers of slope failure still reoccur due to the limitation of the bioengineering technique knowledge. Proper bioengineering material and methods must be carefully selected to overcome the problem. The objectives of this research are to determine the physical and mechanical properties of soil with Vetiver Grass roots as well as the root properties of the Vetiver Grass since these grass types have been applied widely for slope stabilization. The physical properties of soil lab tests have been determined such as compaction test, Atterberg limits test and sieve analysis test. The mechanical properties of soil with and without root grasses have been carried out through the shear box test. For the identification of the root properties of Vetiver Grass, the root morphology and the diameter of the root has been identified. The results for the lab tests conducted showed that the soil with roots have a higher shear strength compared to soil without roots included with FOS (Factor of Safety) calculation proving that the soil with the aid of Vetiver Grass will be effective in retaining soil.

Evaluation of Phytoremediation Potential of Vetiver Grass (Chrysopogon zizanioides (L.) Roberty) for Wastewater Treatment

Water pollution is one of the most critical global issues. Meanwhile, the problem of water pollution of rivers especially in Iran is rising due to expansion of agricultural and industrial applications. Due to a large number of sewer catchments, there are some dam reservoirs like ZHAVE in Iranian state of Kurdistan that have not been able to collect significant amount of water since last 10 years. Removal of heavy metals as contaminants from runoffs and recycling of water is a necessity and a vital issue in the world. Various methods and standards are invented and used to isolate and remove all types of pollutants. This study focuses on the purification and removal of contaminants in water sources using the phytoremediation method by introducing Vetiver grass species in the case of floating treatment wetland (FTW). This study’s preliminary purpose is to investigate a practical remedial solution and improvement methodology for the water quality of reservoirs and rivers by growing the floating Vetiver island method. The results show that following parameters such as COD by 97%, TN by 90%, phosphorus by 66%, TDS by 26%, and evapotranspiration by 40% were reduced. Therefore, we concluded that for a wastewater with varying neutrient concentrations such as in ZHAVE dam, concentration of nutrients N and P was controlled and consequently inhibition and prevention of the eutrophication of water resources in the medium and long term became possible due to reduction in the rate of evaporation from reservoirs.