138. The suitable method for treatment of municipal waste water and aqueous hazardouswaste,
which have less than 1% of suspended solids is:
(a) Activated sludge process ,
(b) Bioreactors,
(c) Lagoons & ponds,
(d) Trickling filter

Best Methods for Treating Municipal Wastewater and Aqueous Hazardous Waste with Low Suspended Solids

Wastewater treatment is a critical aspect of environmental management, particularly in urban settings. When dealing with municipal wastewater or aqueous hazardous waste that contains less than 1% suspended solids, it’s essential to choose the right treatment method to ensure both effective purification and environmental protection. In this article, we will explore some of the most suitable treatment options for such waste streams, including the activated sludge process, bioreactors, lagoons & ponds, and trickling filters.

Understanding Municipal Wastewater and Aqueous Hazardous Waste with Low Suspended Solids

Municipal wastewater and hazardous waste often contain a variety of contaminants, including organic matter, nutrients, and chemicals. However, when these wastes contain less than 1% suspended solids, the treatment process becomes less complex compared to those involving high concentrations of solid particles. These waste streams are typically easier to treat, but the method chosen must still effectively remove soluble pollutants, such as nutrients and toxins.

Suitable Treatment Methods

1. Activated Sludge Process

The activated sludge process is one of the most commonly used biological treatment methods for municipal wastewater. It involves aerating the wastewater in the presence of microorganisms that break down organic pollutants. Since the waste in question has low suspended solids, this process is effective in removing dissolved and colloidal pollutants. The treatment is efficient in degrading organic matter and can be enhanced with additional treatments to address specific contaminants, making it an ideal choice for municipal wastewater treatment.

2. Bioreactors

Bioreactors, such as membrane bioreactors (MBRs), are advanced systems that combine biological treatment with membrane filtration. These are particularly suitable for wastewater with low suspended solids because they can provide high-quality effluent with minimal solids. Bioreactors are known for their ability to treat both organic matter and dissolved chemicals, making them versatile and effective for a wide range of wastewater applications, including hazardous waste treatment.

3. Lagoons and Ponds

Lagoons and ponds are low-cost, passive treatment systems that can be effective for municipal wastewater with low suspended solids. These systems rely on natural biological processes to break down pollutants over time. While they are less energy-intensive than other methods, they require significant land area and time for treatment. Lagoons and ponds are best suited for areas where land availability is not a limitation, and they can provide a more gradual and environmentally friendly treatment process.

4. Trickling Filter

The trickling filter is another biological treatment method that involves wastewater being passed over a bed of microbial biomass (often made of stones or synthetic materials) where microorganisms degrade organic contaminants. This method is well-suited for treating wastewater with low suspended solids, as it provides efficient removal of dissolved organic pollutants. Trickling filters are often used in smaller-scale municipal plants and can be a cost-effective alternative to more complex systems.

Correct Answer:

(a) Activated sludge process

Conclusion

When treating municipal wastewater or aqueous hazardous waste with low suspended solids, the activated sludge process is often the most effective and widely used method. However, each treatment option, such as bioreactors, lagoons & ponds, and trickling filters, has its own set of advantages depending on factors like land availability, energy efficiency, and treatment goals. By understanding these methods, wastewater management facilities can choose the most suitable solution for their specific needs, ensuring cleaner water and better environmental health.