High Efficiency of Waste Stabilization Ponds using Para Grass (Brachiaria Mutica) Vegetation for Treatment of Industrial Wastei Ho Chi Minh City, Vietnam

Abstract

In recent years, wastewater treatment by using biological method has been concerned because it low cost, easy to operate and enviromentally friendly. In this study, stabilization pond – one of the biological wastewater treatment methods has been researched for treating industrial wastewater in Industrial park, District 2, Ho Chi Minh city, Viet Nam. In stabilization pond, Para grass planted on the surface of the pond with roots in the water. Important elements of the treatment process were surveyed to provide optimal operation conditions, include: flow rate of influent, grass cutting cycle, initial COD concentration, fraction of N and P, the height of Para grass after cutting, pH in influent. The results show that Para grass grows well in wastewater and treatment efficiency of stabilization is high when flow rate of influent at 0.12 m3/h and 0.18 m3/h (corresponding to retention time is 7.8 days and 5.3 days, respectively). Besides, Para grass need to be cut periodically for about 20-22 days and the height of grass after cutting from 0.2 - 0.4 m to ensure the best treatment efficiency. Effect of pollution parameters of influent has been also surveyed. The results showed that stabilization pond treats wastewater efficiently when the initial COD concentration is from 200 to 350 mg/l, the fraction of N/P is from 4 to 6 and pH= 7. Wastewater after treatment with stabilization pond meets standards QCVN 40:2011/BTNMT (National Technical Regulation on Industrial Wastewater) with parameters in effluent such as COD, TN, TP, BOD5, Coliform. Moreover, biomass of Para grass after treatment can be used as feed source for livestock and ensure safety according to QCVN 01-183:2016/BNNPTNT. These results show the applicability of stabilization pond using Para grass vegetation in concentrated industrial wastewater treatment with low cost, simple but efficiency, environmentally friendly and towards sustainable development.