Challenges and solutions for sustainable wastewater management

The 3Rs of sustainable wastewater management

• Reduction. Energy consumption in wastewater treatment plants is often associated with the magnitude and type of pollutant load. This, in turn, influences the treatment methods and technologies used in a plant. Energy use intensity ranges from less than 5 to more than 50 kBtu/gallons per day. Lowering high-energy usage and the associated carbon footprint of wastewater treatment are key to sustainable wastewater management. Innovative technologies, such as using a photovoltaic system to eliminate greenhouse gas emissions, are being explored to enhance the sustainability of wastewater treatment processes.

• Reuse. Wastewater reuse or reclamation is a sustainable practice of reusing municipal, sewage and industrial wastewater after treating it to meet fit-for-purpose specifications. Recycled water can be used for irrigation, agriculture, landscaping, municipal water supply, power plants, refineries, mills, factories, concrete mixing and other purposes.

• Recovery. Recovering nutrients from wastewater enables the local and renewable production of fertilizers, reducing the discharge of nutrients into water bodies. Biosolids, a nutrient-rich organic byproduct of domestic sewage treatment, are repurposed for land application, helping achieve the sustainability goals of wastewater treatment.

Developing solutions for sustainable wastewater management

• Identifying sustainability goals. A community’s sustainability priorities can include improving compliance, reducing energy or overall infrastructure costs, addressing wet weather impacts and others. The sustainability goals should align with and reflect the priorities of utility and community sustainability.

• Developing potential strategies for each sustainability goal. Sustainability objectives should be identified while ensuring they are specific, measurable, achievable, realistic and timely (SMART). Potential strategies for each sustainability goal should be identified after analyzing baseline performance. 
  Let’s say the sustainability goal is to manage runoff effectively when it rains and the objective is to reduce projected wet weather combined sewer collection capacity needs by 10%. The combined sewer overflow capacity needs should be determined after analyzing the past and anticipated precipitation event flows.
  Potential strategies may include deploying green infrastructure alternatives that meet the 10% objective.

• Assessing the benefits and total lifecycle cost of each potential strategy. Once alternatives are identified, they should be assessed against the sustainability criteria, evaluating their benefits and full lifecycle costs. Examples of sustainability criteria can include cost-effectiveness, ecological and economic impacts, greater energy efficiency or self-generation of energy.

• Developing a financial strategy. Once an alternative has been finalized, all project capital costs and operations and maintenance costs should be considered with the potential impact of new infrastructure projects on overall costs and revenue.