I. Sludge Reuse – An Inevitable Trend

Sludge from wastewater treatment plants is categorized into two main types: general sludge and sludge containing hazardous components.

Previously considered a business expense due to the need for third-party treatment before disposal, sludge is now seen as a valuable resource thanks to technological advancements. According to the World Bank, over 30% of sludge worldwide is being reused in applications such as agriculture, energy production, and construction materials.

In Vietnam, more than 7 million tons of sludge require treatment annually. However, only a small portion is recycled due to a lack of technology and development within the sludge value chain. This presents a significant opportunity to adopt modern solutions and promote the circular economy model.

II. Current Sludge Reuse Solutions

1. Organic Fertilizer Production

Sludge contains high levels of essential nutrients such as nitrogen, phosphorus, and potassium, making it an ideal raw material for organic fertilizer production. This process not only reduces sludge volume but also provides an environmentally friendly alternative to chemical fertilizers.

2. Biofuel Production

Through processes like anaerobic digestion and pyrolysis, sludge can be converted into biogas or biochar. This provides a renewable energy source, reducing reliance on fossil fuels.

3. Construction Material Production

Treated sludge can be used to manufacture non-fired bricks or cement, helping to alleviate pressure on natural resources and reduce greenhouse gas emissions.

4. Heavy Metal Recovery

For sludge originating from industries such as electroplating, valuable heavy metals can be extracted and reused in industrial production, minimizing environmental waste.

III. Breakthrough Solutions from NGO International

As a high-tech environmental enterprise, NGO International offers practical and effective sludge reuse solutions tailored to the Vietnamese market.

We apply advanced technologies such as:

• Anaerobic Treatment: Further decomposing biological sludge to reduce total sludge volume while generating biogas as a clean energy source.
• Organic Fertilizer Production (without composting): Dewatering and stabilizing general sludge, then combining it with organic materials to produce agricultural fertilizers.
• Industrial Sludge Solutions: Given the diverse nature of sludge from different industries, we customize reuse solutions accordingly.

International Collaboration

NGO collaborates with international organizations and research institutes to implement cutting-edge technologies in Vietnam. This ensures our solutions are both effective and compliant with global standards.

With extensive expertise and experience, NGO International is committed to supporting businesses in transitioning to a circular economy model. Contact us today to explore the best sludge reuse solutions for your business!

Contact Information

Interested in sludge reuse solutions? Contact NGO via phone at 024.7300.0890 or email office@8ngo.com for direct consultation.

From 2024 onwards, businesses will organize and conduct facility-level greenhouse gas inventories and prepare facility-level greenhouse gas inventory reports every two years, submitting them to the provincial People’s Committee for verification and then forwarding them to the Ministry of Natural Resources and Environment.

Businesses must be able to capture and manage risks related to GHG emissions to ensure long-term success in a competitive business environment and comply with legal policies.

B. Legal Regulations on Corporate Greenhouse Gas Inventories

1. Environmental Protection Law 2020 (Law No. 72/2020/QH14)

From January 1, 2022, the Environmental Protection Law 2020 (Law No. 72/2020/QH14) came into effect, requiring businesses in the List of Greenhouse Gas Emitting Facilities to conduct Greenhouse Gas inventories.

2. According to Circular No. 96/2020/TT-BTC

Section 2, Article 10 of Circular No. 96/2020/TT-BTC, which provides guidance on information disclosure in the securities market effective from February 1, 2021, mentions the inclusion of GHG emissions reports in the Annual Report applicable to public companies. The financial information in the Annual Report must be consistent with the audited financial statements.

Additionally, Section 6 of Part II in Appendix IV outlines other related reporting requirements, including:

• Total direct and indirect GHG emissions.
• Measures and initiatives to reduce GHG emissions.

C. Services Provided by NGO

Climate change is increasingly impacting the business operations of companies in every country worldwide. Business owners, investors, and financial organizations need to consider ESG (Environmental – Social – Governance) values and sustainability in their investment decisions.

Climate change is increasingly impacting the business operations of companies in every country worldwide. Business owners, investors, and financial organizations need to consider ESG (Environmental – Social – Governance) values and sustainability in their investment decisions.

Large GHG-emitting businesses, with the obligation to reduce GHG emissions, will have two choices: (1) Invest in solutions to reduce GHG emissions within their operations; and/or (2) trade on the ETS and carbon market.

As a provider of environmental solutions, including CLIMATE CHANGE MITIGATION solutions, NGO offers the following services:

• Measurement and inventory of corporate GHG emissions.
• Consulting and developing GHG emission reduction solutions in business operations.
• Advising and supporting businesses to comply with legal regulations on GHG inventories and emission reduction.

We are committed to working alongside businesses to turn environmental and GHG issues into competitive advantages in today’s business environment.

Businesses interested in GHG inventory and emission reduction services can contact NGO via phone at (+84)24.7300.0890 or email: office@8ngo.com for direct consultation.

Air pollution includes pollutants in solid form (dust), gaseous form (toxic gas vapors), and liquid form (various solvent vapors). Conventional exhaust gas treatment solutions address all three types of pollution to ensure compliance with current QCVN discharge standards. Greenhouse gas treatment is a new approach to air pollution control, aiming for thorough removal of greenhouse gas components (CO2, CH4, NOx…) to levels even lower than emission standards, ultimately striving for zero emissions.

Greenhouse gases are gases capable of absorbing long-wave radiation (infrared) reflected from the Earth’s surface when exposed to sunlight, then redistributing heat back to the Earth, causing the greenhouse effect.

1. Sources of Emissions

• Production activities, transportation, daily life, and natural processes (such as organic decomposition) can all generate emissions and harmful substances that affect human health, as well as plant and animal life.
• Pollutant gases may exist in inorganic forms such as ammonia and hydrogen sulfide or in organic groups such as pesticides and organic solvents (methane, butane, benzene, xylene, cyclohexanone, toluene…). Some pollutants are difficult to quantify, evaporating at normal temperatures, such as VOCs (volatile organic compounds), which are commonly found in industries like food production (spices), cosmetics, etc.
• Emissions also generate odors, meaning that the process of gas treatment is inherently linked to odor removal.
• Exhaust gas treatment must comply with current legal regulations and standards, whereas greenhouse gas treatment goes beyond meeting standards by also aiming to eliminate and minimize greenhouse gas components, including gases not specified in emission standards.

2. Exhaust Gas and Greenhouse Gas Treatment Process

3. Some Solutions for Exhaust Gas Removal

3.1. Absorption Method

The fundamental principle of gas absorption is to create contact between the pollutant-containing gas stream and absorbent solution droplets, which are typically sprayed in small sizes and at high density. Pollutants are separated through dissolution in the absorbent liquid or by a chemical reaction between the pollutants and the absorbent solution.

The efficiency of the process depends on several factors, including the contact surface area between the gas stream and absorbent droplets, contact time, absorbent solution properties, exhaust gas temperature, the relative motion direction of the gas stream and solvent, and gas flow rate.

Process stages:

• Pollutant molecules diffuse to the absorbent liquid’s surface.
• Gas penetrates and dissolves in the absorbent.
• Dissolved gas diffuses deeper into the absorbent liquid.

3.2. Adsorption Method

Gas adsorption is based on the principle that gases are adsorbed by solid materials. This process occurs when the molecules or atoms that need to be adsorbed accumulate only on the surface of the solid or within its pores. Gas adsorption operates on the principle of direct contact between the gas stream and the solid adsorbent as it moves through a bed of adsorbent material contained within a device. Adsorbents can be materials with natural physical or chemical properties, such as activated carbon, silica gel particles, etc.

Advantages:

• Handles varying flow rates.
• Suitable for different concentrations of organic compounds.
• Reusable or recycled materials (e.g., fly ash) can be employed.
• Simple operation.
• Space-saving.

Exhaust gases from industries such as pharmaceuticals, food and beverage production, wastewater treatment, chemicals…….

The adsorbent material can be selected from various options besides activated carbon, depending on the specific type of gas that needs to be removed.

3.3 Oxidation Methods

• Thermal Oxidation (Chemical Oxidation):

High temperatures are used to combust or completely oxidize hazardous compounds in the exhaust gas, converting them into safe substances such as CO₂ and H₂O.

Typically, these are refractory organic compounds, often with complex ring structures such as dioxins, furans, and solvent compounds from painting processes. Incineration is the most suitable method for treating these pollutants.

Combustion of pollutants requires additional energy provided by burning fuel. Common fuels used for incinerators include FO oil, DO oil, or gas. The components of solid, liquid, and gaseous fuels generally include C, H, O, S, ash (A), and water vapor (W). Combustion generates dust, CO₂, CO, SO₂, H₂O, and unburned hydrocarbons (HC).

Advantages:

– Thorough removal of organic compounds.

– Suitable for biogas treatment.

• UV Treatment Method

Exhaust gas treatment technology using UV light utilizes ultraviolet light with a short wavelength range from 100 nm to 400 nm, which acts on particles and molecules in exhaust gas. UV rays can break chemical bonds and alter the structure of pollutants, effectively reducing their toxicity or eliminating them. It is applied in treating VOCs, H₂S, NH₃, and odorous gases.

Free negative and positive electrons provided by oxygen combine with oxygen molecules in the air to create ozone, a highly oxidizing compound:

UV + O2 → O– + O * (oxidation reaction) O + O2 → O3 (ozone)

• Regenerative Thermal Oxidation (RTO) / Regenerative Catalytic Oxidation (RCO):

Regenerative Thermal Oxidation (RTO) equipment is widely accepted for controlling volatile organic compounds (VOCs) and hazardous air pollutants (HAPs). RTO can be modified by adding catalysts, commonly referred to as Regenerative Catalytic Oxidation (RCO).

Depending on the characteristics of specific emissions from each facility, evaluating the primary components of the exhaust gas is necessary to select appropriate removal technology or combine multiple processes to meet treatment standards.

4. Current Legal Regulations on Industrial Emission Standards

• QCVN 19:2009/BTNMT – National Technical Regulation on Industrial Emissions for Dust and Inorganic Substances.
• QCVN 20:2009/BTNMT – National Technical Regulation on Industrial Emissions for Certain Organic Substances.
• QCVN 21:2009/BTNMT – National Technical Regulation on Industrial Emissions from Chemical Fertilizer Production.
• QCVN 22:2009/BTNMT – National Technical Regulation on Industrial Emissions from Thermal Power Plants.
• QCVN 23:2009/BTNMT – National Technical Regulation on Industrial Emissions from Cement Production (issued under Circular No. 25/2009/TT-BTNMT dated November 16, 2009, by the Minister of Natural Resources and Environment regulating national environmental technical standards).
• QCVN 34:2010/BTNMT – National Technical Regulation on Industrial Emissions from Petroleum Refining for Dust and Inorganic Substances (issued under Circular No. 42/2010/TT-BTNMT dated December 29, 2010, by the Minister of Natural Resources and Environment regulating national environmental technical standards).
• QCVN 51:2017/BTNMT – National Technical Regulation on Industrial Emissions from Steel Production (issued under Circular No. 78/2017/TT-BTNMT dated December 29, 2017, by the Minister of Natural Resources and Environment issuing national environmental technical standards).

QCVN 19:2024/BTNMT – National Technical Regulation on Industrial Emissions

Replacing QCVN 19:2009/BTNMT and QCVN 20:2009/BTNMT, this regulation will take effect from July 1, 2025.

Accordingly, facilities already in operation and investment projects that have received approval for the environmental impact assessment report, or have had their complete and valid application for environmental impact assessment review, environmental permit issuance, or environmental registration accepted by a competent state authority (hereinafter referred to as “ongoing investment projects”) before this Circular takes effect may continue to comply with the national technical regulations on emissions based on their respective industry, business, or service sector, as well as local government regulations (including local environmental technical regulations on emissions) until December 31, 2031.

Some Practical Images:

NGO is confident in being one of the few units with in-depth expertise in consulting and designing air emission and greenhouse gas treatment systems. Our capabilities include calculating flow rates, pollutant concentrations, and emissions generated from industrial activities to design tailored solutions that comply with discharge regulations and meet investor requirements at an optimized cost.

Please contact us via Zalo or our Hotline for detailed consultation.

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