How can wastewater treatment plants be designed to be sustainable and environmentally friendly?

Incorporate energy-efficient technologies, such as renewable energy sources, to minimize the carbon footprint of wastewater treatment plants and use water reuse systems to repurpose treated wastewater for non-potable purposes, reducing demand on freshwater resources and promoting sustainable water management.

Before going into details, I would recommend the use of Nereda biological wastewater treatment. Within a Nereda reactor, you will see a simple three-step cycle, the purifying biomass grows naturally as compact aerobic granular sludge, with superb settling properties. An important feature of the granules is that aerobic and anoxic/anaerobic zones co-exist. This enables a large variety of biological processes to happen simultaneously, like nitrification, denitrification and biological phosphate removal. The amount of mechanical equipment is much less than in conventional processes. Operation & Maintenance costs are much lower thanks to the reduction in mechanical equipment, chemical-free operation and high energy efficiency of the process.

Compared to conventional activated sludge technologies, the biological treatment power of Nereda technology is much larger due to a considerably higher concentration of biological active mass is applied; that in addition has a much higher content of microorganism that are crucial for biological nitrogen and phosphate removal. The sludge can be fully reused. This is reflected in a treated water quality that is at least similar, but typically better than what other biological technologies can achieve. Just like for activated sludge technologies, whenever necessary for particular stringent discharge demands or water reuse, polishing steps like constructed wetland treatment, sand filtration or membranes can be applied

As mentioned before, tertiary polishing steps can be added to this process, in order to meet environmental standards. Examples are constructed wetlands (horizontal or vertical flow design) Flowfields, vitalisation treatment or artificial waterfalls.

As a civil engineer, designing sustainable and environmentally friendly wastewater treatment plants involves considering all dimensions of sustainability - economic, environmental, and social. The design should focus on optimizing the removal of pollutants, such as biodegradable and nonbiodegradable organic matter, suspended solids, turbidity, nutrients, heavy metals, pesticides, pathogens, etc. The selected treatment techniques must be adapted to the nature of these pollutants. Furthermore, the design should aim for low energy consumption, cost-effectiveness, and maximum reclaimed wastewater.

Wastewater treatment plants can prioritize sustainability and environmental friendliness through various design approaches. Implementing energy-efficient technologies like solar panels or anaerobic digesters can reduce reliance on non-renewable energy sources. Utilizing natural treatment systems such as wetlands or constructed wetlands can enhance water quality while minimizing the need for chemicals. Additionally, incorporating green infrastructure like permeable pavements and rain gardens can help manage stormwater runoff effectively. By integrating these strategies, wastewater treatment plants can minimize their environmental footprint and contribute to a more sustainable future.

Extensive life cycle analyses have revealed that Nereda technology as a very sustainable technology. Compared to conventional wastewater treatment processes, Nereda not only has significantly lower energy consumption and associated greenhouse gas emission, but also produces, commonly without the use of waste generating chemicals, a remarkably high effluent quality. On top of this, the technology requires fewer construction materials and less mechanical equipment resulting in a better environmental construction profile and a small physical footprint. This implies that a nereda plant can be built on the site of an older technology plant and even use less space, creating a win-win situation.