Study on the development of national technical regulation on industrial wastewater for bioethanol production
According to Project No. 177 of the Government, Petrovietnam (PVN) has established a strategy to develop biofuels until 2015 with a vision to 2025. So far PVN has cooperated with partners to actively invest in the construction of ethanol fuel (bioethanol) plants with a total capacity of 300 million liters per year. In 2012, two of the three PVN’s biofuel production plants, Dung Quat and Binh Phuoc, have started commercial production.
The process of producing bioethanol creates a large amount of wastewater containing high concentrations of pollutants and difficult to be treated. Currently, all plants must apply the QCVN 40:2011/BTNMT (QC-40) – National technical regulation on industrial wastewater. However, it is difficult to treat wastewater to meet the above regulation due to complicated wastewater composition, high organic content and difficult to be decomposed. Most of the bioethanol plants in Vietnam use modern treatment technologies but due to the specific nature of production process, raw materials and limited experience in wastewater treatment, the quality of treated wastewater is still not able to satisfy QC-40 regulation in color, COD, BOD, Total Nitrogen, Total Phosphorus, … To meet the current regulation, plants must invest in more advanced physico-chemical treatment systems which consume large quantities of chemicals and consequently affect the total cost of production as well as the receiving environment of wastewater.
Due to the specific characteristics of the bioethanol industry as mentioned above and some inadequacies when applying discharge regulation, it is necessary to review and amend the current environmental regulation to meet the requirements of the bioethanol development project of the Government. Beside learning from experiences in the application of environmental regulation, the combination of consultation with experts and compilation from different sources of documents and regulation of other countries in the same region or developed countries and international organizations should also be taken into consideration.
For the purpose and requirements mentioned above, PVN’s Health Safety Environment Division has assigned the Research and Development Centre for Petroleum Safety and Environment (CPSE) – Vietnam Petroleum Institute (VPI) to construct a draft national technical regulation for wastewater from bioethanol production plants.
When developing the draft regulation, the authors have consulted the standards and regulations of some countries whose bioethanol industry has many similarities to Vietnam such as Thailand and India, and some specific industrial regulations issued in Vietnam. Based on the above, the authors selected 07 (seven) bioethanol parameters of waste water including pH, COD, BOD, TSS, total nitrogen, total phosphorus and color. The pollutant concentrations were calculated by the weight of pollutants per volume unit of waste water. To determine the standard limits, the authors gave the explanation for each proposed parameter and determined the limit values by testing the toxicity of Dung Quat and Binh Phuoc bioethanol plants’ wastewater on zebrafish (Danio rerio) and giant tiger prawn (Panaeus monodon) using widely published toxicological analysis procedures, such as APHA 8910, 8740; OECD 203 (the values are determined based on the onset of lethality in exposed population at LC0).
Based on the above arguments, the proposed regulation for receiving environment which is not domestic water supply (column B) should be adjusted, as follows: COD from 150 mg/l to 350 mg/l; color from 150 Pt-Co to 300 Pt-Co, total nitrogen from 40 mg/l to 100 mg/l; The remaining parameters’ values are equal to the ones given in QC-40. For the receiving environment which is domestic water supply (column A), the values of the controlled parameters still equal to the ones in QC-40. The project will be submitted to the Ministry of Natural Resources and Environment for consideration and incorporation into the plan for promulgation of the National Technical Regulations on wastewater for specific industrial sectors. Specific regulations will help bioethanol plants gain advantages in production and environment protection as well as achieve the goal of the Government bioethanol project.