This article is the second in a short series on municipal growth. Read the first article, on rural townships and areas, here, and the second article, on cities, here.

Metropolitan growth, from major cities on out into the exurbs, is a double-edged sword. On one hand, this growth confers significant economic benefits to residents and businesses in multiple jurisdictions. On the other hand, when it comes to wastewater treatment options for cities, growth can introduce complex infrastructure challenges. 

In major metropolitan areas, where space is limited as population density compounds, traditional expansion of wastewater treatment facilities is often impractical. As these areas continue to grow, adopting scalable and efficient wastewater treatment systems becomes critical.

Metropolitan Growth and Wastewater Challenges

The growth of metropolitan areas is typically not in the physical space but in population and economic output. For instance, areas like greater Dallas and greater Atlanta have seen population increases of more than 10% in the last decade, compounding pressure on existing municipal wastewater infrastructure. 

So, where does that leave the public health needs of a growing population?

These sprawling but finite metro areas face challenges that are similar to singular cities but unique in their scope. Limited available space for new wastewater treatment plants leads to the necessity for compact and efficient systems, perhaps even across jurisdictional lines. 

Higher population densities in those areas then result in stricter environmental regulations, as those mandated by the Environmental Protection Agency, to mitigate the impact on public health and ecosystems. Because of this, fluctuations in wastewater volume ultimately require adaptable treatment processes.

Wastewater Reuse Opportunities

Advanced wastewater treatment technologies, particularly MBR systems, not only manage these challenges but also turn treated wastewater into a resource, promoting sustainable urban development. This is where the benefits of efficient wastewater treatment and high-quality effluent can fall to county budgets’ bottom lines. 

Suburbs and urban areas can use high-quality treated wastewater for irrigating crops, reducing the strain on freshwater resources. Similarly, in metropolitan parks and green spaces, often run by county-level public works agencies, treated wastewater can be used for irrigation, conserving potable water for residential and commercial use.

Reclaimed water can also serve industrial wastewater applications, such as cooling water in manufacturing plants, which are often located near metropolitan areas to minimize logistics costs.

Even at the municipal level, reclaimed water is ideal for street cleaning and public facility maintenance, helping cities reduce their freshwater usage.

The Case for Decentralized Solutions

Given the potential benefits of MBR technology, the challenge lies in determining the optimal strategies for integrating it into these spaces as decentralized wastewater treatment operations. The question becomes how to decentralize wastewater treatment systems effectively.

MBR systems offer flexibility and efficiency, particularly in sprawling urban regions where centralized sewage treatment may not be feasible or cost-effective. 

Thus, decentralized MBR systems can be implemented directly within neighborhoods, commercial districts, or industrial areas, allowing for localized treatment and immediate reuse of treated wastewater. This proximity reduces the need for extensive pipeline networks, lowering infrastructure costs, minimizing traffic disruptions,  and minimizing energy consumption associated with pumping water over long distances.

Major metropolitan areas often face spatial constraints that make large-scale centralized facilities impractical. Decentralized systems can be tailored to fit limited spaces and designed to blend with urban aesthetics, providing effective sewage treatment without requiring large tracts of land.

By dispersing wastewater treatment operations across multiple decentralized units, cities can enhance their overall resilience against system failures or disruptions. If one unit encounters issues, others can continue operating, thereby ensuring continuous treatment and supply of reclaimed water.

Decentralized MBR systems support sustainable economic development by enabling water recycling and reuse at the local level. This is important in water-scarce regions where conserving water resources is critical; look to California for emerging examples of reuse regulations. The high-quality effluent from MBR systems is ideal for non-potable applications such as irrigation, industrial cooling, and toilet flushing, which further promotes water conservation.

Implementing decentralized wastewater treatment plants often requires engagement with local communities to ensure acceptance and participation. This engagement can lead to increased awareness about water conservation practices and the benefits of wastewater reuse, fostering a culture of sustainability that compounds over time.

Decentralized systems can also create economic opportunities by allowing communities to manage their own wastewater treatment facilities and reuse treated water for commercial and agricultural purposes. This can generate savings on water bills and reduce dependency on municipal water supplies.

Implementing MBR in Urban Planning

Major metropolitan areas are not monoliths, however; it takes serious cooperation to implement new ideas. This work demands strategic collaboration across multiple jurisdictions. As cities expand into their suburban areas, the lines between urban centers and their surrounding suburbs blur, creating a complex interdependence in infrastructure needs, particularly in wastewater management. 

Metropolitan areas and their suburbs can benefit significantly from developing unified regional wastewater management strategies. By combining resources and planning efforts, multiple jurisdictions can achieve greater efficiencies in wastewater treatment systems. This unified approach allows for the optimization of MBR systems across broader areas, reducing redundancy and enabling cost-sharing for infrastructure upgrades.

Collaborative efforts in wastewater management can also leverage economies of scale, making large-scale MBR systems more economically viable. For example, a single, well-planned large-scale MBR facility can serve multiple communities more effectively than several smaller systems. This not only optimizes capital investments but also minimizes operational costs over time, benefiting all participating jurisdictions.

A collaborative planning approach allows cities and suburbs to integrate their infrastructure development plans, ensuring that MBR systems are designed to accommodate current and future growth seamlessly. This integration is particularly crucial in metropolitan areas where urban sprawl can extend infrastructure stress. Planning together, communities can ensure that the scalability and modularity of MBR technology are fully utilized to meet the dynamic needs of an expanding population.

Multi-jurisdictional planning helps in uniformly addressing the environmental regulations that may vary across regional boundaries. By adopting a collective approach to regulatory compliance, metropolitan areas and their suburbs can streamline the implementation of MBR systems, ensuring that all communities meet or exceed the required wastewater treatment standards.

Conclusion

As metropolitan areas evolve, integrating scalable, efficient wastewater treatment technologies like MBR is essential. These systems not only support urban expansion but also offer significant environmental benefits, positioning cities for sustainable growth and resilience against future challenges.