With CRWA’s Smart Sewering project, conventional wastewater infrastructure is reimagined and redesigned to support urban growth and environmental restoration.
At CRWA we are working toward a resilient and equitable future for humans and nature. Small scale distributed wastewater treatment and energy generation infrastructure provides the resiliency and redundancy necessary in a changing climate. This infrastructure will replicate natural systems and integrate management of drinking water, wastewater, and stormwater.
Traditional urban water infrastructure is having devastating effects on our surface and groundwater resources. Groundwater, which supplies the necessary continuous base flow to the Charles River, is aggressively pumped to provide potable water for cities and towns. It also infiltrates into sewer pipes where energy is wasted pumping and treating it and it is discharged far from its source, permanently lost from the local aquifer. The Charles River and surrounding urban watersheds lose about 90 million gallons a day through sewer infiltration - clean, freshwater that is ultimately discarded into Boston Harbor. Extensive development and impervious cover prevent rainwater from getting into the ground to recharge these lost groundwater sources. Instead, rainwater runs across pavement, picking up pollutants and discharging them to local water bodies. Every year, about 20” of rain that should be infiltrated becomes stormwater runoff. Climate change predictions for our region call for significant increases in large, intense rain events which will lead to increased flooding. In addition, traditional water infrastructure misses the opportunity to recapture the energy and resources in our wastewater.
CRWA envisions a new paradigm in urban water infrastructure that more closely integrates the management of stormwater and wastewater.
Wastewater treatment will take place at decentralized Community Water and Energy Resource Centers (CWERCs). Water will be treated while energy is captured from both the biological components through anaerobic digestion and the physical components through thermal heat capture. Organic food waste will be diverted from landfills to these facilities, reducing trucking and capturing the biogas produced by the degrading organic matter. Solid waste will be transformed into beneficial products such as compost for local food production. Treated water will be reused for non-potable uses such as heating and cooling, manufacturing or irrigation, reducing the demand on potable water sourced from local ground or surface water resources.
Some of the treated water will also restore the natural environment and beautify our neighborhoods through the creation of stream and wetland features and through groundwater infiltration. Green infrastructure fed by treated water will also provide treatment and storage of stormwater, integrating the two systems. Human water use will be merely a bend in the river, fitting into the natural cycle, not destroying it.
Charles River Watershed Association has done extensive research and modeling to bring our vision from an idea to a reality. Working with wastewater professionals at Natural Systems Utilities and economists at Industrial Economics we have carefully examined the costs and benefits of Community Water and Energy Resource Centers (CWERCs) and associated green infrastructure districts. This analysis was done for a representative urban neighborhood, roughly 1600 acres in size with 79% impervious cover.
The study found that for every 2 million gallons of wastewater treated, about what 20,000 people generate each day and 4 trucks of food scraps from nearby food producers and restaurants, a CWERC could produce:
The study found that approximately 50 acres of green infrastructure will: