In the context of industrialization and modernization, industrial emissions are becoming one of the largest sources of air pollution. To control and minimize the negative impacts on public health as well as the environment, the construction and application of exhaust gas treatment systems in accordance with standards is a mandatory requirement for all manufacturing enterprises. This article will help you better understand the concept, role, current legal regulations, and design steps for exhaust gas treatment systems that meet QCVN and international standards.
An exhaust gas treatment system is a combination of structures, equipment, and technological solutions designed to remove or minimize pollutants in emission streams from industry, domestic activities, or production processes. The main goal is to ensure that exhaust gases after treatment meet environmental standards before being released into the atmosphere, thereby protecting public health and reducing negative impacts on air quality.
The main functions of an exhaust gas treatment system include:
Currently, the construction and operation of exhaust gas treatment systems in Vietnam are regulated by the Law on Environmental Protection 2020 and guiding documents such as Decree 08/2022/NĐ-CP and Circular 02/2022/TT-BTNMT. Emission sources must comply with national technical regulations (QCVN), including QCVN 19:2009/BTNMT (industrial emissions of dust and inorganic substances), QCVN 20:2009/BTNMT (industrial emissions of organic substances), and sector-specific QCVNs (cement, steel, thermal power, textile dyeing, etc.). In addition, the Ministry of Natural Resources and Environment is developing new QCVNs with stricter limits, particularly for fine dust (PM2.5, PM10), NOx, SO₂, and VOCs.
During the investment process in exhaust gas treatment systems, enterprises are required to conduct Environmental Impact Assessments (EIA) or Environmental Protection Plans, and select treatment technologies appropriate to the emission loads. Once in operation, treated exhaust gases must meet column A or B of the QCVN, depending on the receiving area (urban areas, industrial zones, or environmentally sensitive regions). Furthermore, many large-scale or high-pollution-risk facilities are required to install automatic exhaust gas monitoring systems that transmit data online to the Department of Natural Resources and Environment for continuous supervision. This mandatory management trend not only ensures legal compliance but also encourages enterprises to adopt cleaner and more sustainable technologies.
The first step in designing an exhaust gas treatment system is surveying and evaluating the emission sources. This includes identifying locations, production processes, as well as the composition and characteristics of generated exhaust gases. The survey results help accurately identify pollutants such as dust, SO₂, NOx, CO, VOCs, as well as gas properties (temperature, humidity, pressure). This is an essential foundation for selecting the right technology and system scale.
After the survey, it is necessary to measure and calculate the exhaust gas flow rate (Nm³/h) and pollutant load (mg/Nm³). These parameters determine equipment size, fan capacity, and treatment requirements to ensure the output meets QCVN standards. If calculations are inaccurate, the system may become overloaded or perform inefficiently, causing wasted investment and operational costs.
Based on data on exhaust gas composition and pollutant load, engineers will select suitable treatment technologies. For example: cyclone or ESP for dust, absorption towers for SO₂ and NOx, activated carbon for VOCs, or catalytic systems for toxic gases. The selection must balance treatment efficiency, investment cost, operational expenses, and suitability for the industry’s characteristics.
Once the technology is selected, a process flow diagram is developed to describe the stages from gas collection to treatment and final release into the environment. Equipment must be laid out logically within the factory or industrial zone to ensure convenient operation, maintenance, and compliance with occupational safety and fire protection regulations. This step transforms theoretical calculations into practical engineering solutions.
Finally, an operation and maintenance plan must be established. This includes energy consumption standards, replacement frequency of filter media, cleaning of equipment, inspection of fans, pipelines, and automatic emission monitoring systems (if applicable). Regular maintenance planning helps ensure stable operation, long-term treatment efficiency, and compliance with environmental standards.
Design and construction steps of exhaust gas treatment systems according to current QCVN.
During the design process of exhaust gas treatment systems, enterprises need to consider key factors to ensure technical efficiency and economic feasibility.
Detailed assessment of working conditions: Before proposing a design solution, a comprehensive survey of exhaust gas characteristics must be conducted. Parameters such as flow rate, temperature, pressure, humidity, dust composition, oxygen concentration, and chemical properties of gases directly affect treatment efficiency. Thorough surveys help select appropriate technologies and avoid system overload.
Choosing optimal treatment technology: The exhaust gas treatment solution must fit the specific industry and emission scale. Depending on emission characteristics (dust, SO₂, NOx, VOCs, odors…), technologies such as cyclones, electrostatic precipitators, absorption, adsorption, or catalytic treatment can be applied. In addition, the operational capacity of personnel and maintenance requirements should also be considered to ensure long-term system stability.
Calculating investment and operating costs: The construction and maintenance costs of the system are crucial factors. An effective system must not only meet QCVN environmental standards but also be cost-effective, easy to manage, and operate. Balancing initial investment costs, energy consumption, labor, and maintenance expenses will help optimize the enterprise’s economic efficiency.
Designing and operating an exhaust gas treatment system is not only a legal responsibility but also a sustainable solution for long-term business development. Compliance with the Law on Environmental Protection 2020, relevant QCVNs, and the adoption of appropriate treatment technologies will ensure exhaust gases meet standards, protect public health, and mitigate climate change. Enterprises that invest properly in exhaust gas treatment systems will reduce legal risks and enhance brand reputation with partners and society.
