Treatment of sewage sludge through composting digestion method

26/06/2021

 

Xử lý bùn thải bằng phương pháp Ủ phân compost

Nanoen  The composting method is also simply understood as the process of decomposing organic waste into humus after a suitable period of time.

1. INTRODUCTION

One of the current issues for businesses is the treatment of wastewater generated from their production and processing activities. Concurrently, the amount of sludge generated during the wastewater treatment process is also a concern for businesses because it requires significant costs to handle. Typically, the cost for businesses to treat this sludge accounts for about 40% - 60% of the total wastewater treatment expenses.

Sludge is usually treated by facilities and businesses using sludge dewatering machines or sludge drying beds, and then transported elsewhere for further treatment. However, these measures only reduce the volume of sludge without completely treating it and often require a relatively long time.

Therefore, finding an effective and cost-saving method for sludge treatment is a matter of concern for businesses. Currently, many facilities and businesses choose to apply the composting method to treat the sludge generated during the wastewater treatment process. This method helps reduce the cost of sludge treatment while also potentially generating income through the sale of compost after treatment.

Industrial sludge

Industrial sludge

 

2. COMPOST (ORGANIC FERTILIZER)

Compost, also known as organic fertilizer, is organic matter that has been decomposed and recycled into a type of fertilizer to improve soil quality. Organic fertilizer is considered an important component in organic agriculture.

In agriculture, organic fertilizer is commonly used in gardens, landscaping, and farming.

In ecosystems, organic fertilizer benefits erosion control, soil and land reclamation, and the establishment of wetland areas.

Phân Compost

Compost

3. COMPOSTING METHOD AND PROCESS

The composting method is simply understood as the process of decomposing organic waste into humus over a suitable period of time.

Read more: Composting method at home

Composting involves several steps, including processes that are closely monitored and checked against input parameters such as temperature, moisture, air, pH level, and a source of carbon and nitrogen. Since bacteria require oxygen and nutrients to grow, develop, and decompose organic matter, it is essential to provide adequate airflow during the composting process.

The components of composting materials include:

  • Carbon (energy source): Materials containing carbon (such as straw, dried grass, etc.) support the oxidation process, providing suitable heat levels.

  • Nitrogen: Acts as a nutrient for bacteria growth to oxidize carbon.

  • Oxygen: Facilitates aerobic bacteria in decomposing organic matter.

  • Water: Provides adequate moisture for microbial activity during decomposition.

  • Temperature: Maintains an appropriate level for microbial activity.

  • And some buffering materials such as: Straw, sawdust, wood chips, animal manure, etc.

Rơm khô được sử dụng làm chất đệm trong ủ phân Compost

Dried straw is used as a bulking agent in composting

4. PHASES OF PREPARING COMPOSTING

There are several methods for composting, such as windrow composting, forced aeration composting, long windrow composting, container composting, and vermicomposting.

- Preparing composting materials phase:  

 + The organic waste materials used as raw materials (in this case, sludge from the XLNT system).

   + Measuring the Carbon-to-Nitrogen (C/N) ratio: Typically, a C/N ratio of 25:1 to 40:1 yields high efficiency, facilitating rapid and effective decomposition.

  • If the C/N ratio > 40:1: Nitrogen supplementation is required in the compost batch.

  • If the C/N ratio < 25:1: Carbon supplementation is needed in the compost batch.

   + Inoculating the composting bin with microbial cultures or aged compost from previous batches.

Phương pháp ủ phân theo luống

Windrow composting method

- Menuration phase (about 21 days):

   + After adding the bulking material and microbes, the raw material mixture is loaded into the composting bin, mixed, and covered with a tarp.

   + Regular monitoring of the temperature and moisture level in the composting bin is necessary throughout the process. Additionally, the compost mixture should be turned once a week to ensure adequate oxygen supply for the microbes.

  • Regarding temperature: In the initial phase, the temperature rises quite high (around 65-70°C) and needs to be maintained at this level for at least 3 days. After the first week, the temperature will decrease to 45-50°C.

  • Regarding moisture: The moisture level in the composting bin should be maintained at around 40-60%.

- Maturation phase (compost maturity):

After about 21 days of composting, if the compost in the bin appears black, crumbly, with a strong vinegar-like odor, and has a moderate warmth, and the materials have completely decomposed, the compost can be used.

Container composting method

5. ADVANTAGES AND DISADVANTAGES OF COMPOSTING METHOD

Advantages:

  • Fast composting time (approximately 40-60 days), allowing the compost to be used as fertilizer for plants relatively quickly.

  • Inactivation of disease-causing microorganisms.

  • Reduction of waste treatment costs for businesses.

  • Potential economic value through the sale of compost as fertilizer for agriculture.

  • Suitable for implementation in eco-industrial park models.

Disadvantages:

  • Requires a relatively large area to construct a composting site.

  • The composting process needs to be closely monitored.

  • The composting process may generate unpleasant odors and affect aesthetics.

  • Difficulty in application in cold areas, areas with high humidity, or regions with prolonged rainy seasons.

6. CONCLUSION

Treating sludge using the composting method is an environmentally friendly approach, primarily utilizing surplus raw materials from wastewater treatment systems. This helps reduce costs and ensures thorough sludge treatment, while also minimizing byproducts compared to conventional sludge treatment methods and providing a source of income. Ultimately, implementing an industrial symbiosis model contributes to building a green industry for the future.

A reputable provider of environmental dossier services and construction, operation, maintenance, and servicing of wastewater treatment systems

Nanoen is a reputable provider of environmental dossier services and construction of wastewater treatment systems. Over the years, Nanoen has earned the trust of customers through honesty, dedication, and responsibility towards both customers and company products.

With experienced staff, Nanoen offers comprehensive services from environmental dossier consulting to design and construction, operation of environmental treatment systems, provision of microbial products, and sludge dewatering services.

Nanoen is committed to providing the best service experience tailored to the needs of customers.

Nanoen 


 

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