Community Water and Energy Centers produce reliable, renewable and resilient energy and clean water while restoring the natural environment.
Charles River Watershed Association (CRWA) is designing water infrastructure for the 21st century and beyond. Our approach is to design infrastructure that works with or replicates natural water, nutrient and carbon cycling processes and integrates water management, bringing together management of potable water, wastewater, stormwater, and surface and groundwater. Small scale Community Water and Energy Resource Centers (CWERCs) will capture previously discarded renewable energy sources in wastewater and organic food waste. Wastewater treatment costs will be subsidized by the sale of energy, treated water, recovered nutrients and compost. This new model of infrastructure respects and supports the natural and historical flow of surface and ground water; rendering human water demand merely a bend in the river, working with the natural cycle, not destroying it.
Instead of a large centralized system that moves water from central Massachusetts for a single use in our homes and then discharges it miles off the coast of Boston Harbor where it becomes salt water, water will be managed locally in distributed CWERCs, protecting and preserving our freshwater resources. Wastewater treatment takes place in small scale, enclosed systems. The water itself is reclaimed to potable standards for re-use and the wastewater organics are used to generate electric energy through anaerobic digestion. Thermal energy in the wastewater is captured for use heating and cooling surrounding buildings and homes. The wastewater produced by 10,000 people can produce at least 16% of their heating and cooling needs and 2% of their electricity demand. Organic food waste, diverted from landfills, reduces greenhouse gas emissions and truck hauling. Solid waste is transformed into beneficial products such as compost for local food production. Treated water is also used to restore the natural environment and beautify our neighborhoods through the restoration of streams and wetlands lost to development.
What actions do you propose?
Traditional urban water infrastructure is having devastating effects on our surface and groundwater resources. Groundwater, which supplies the continuous base flow to the Charles, or any river, is aggressively pumped to provide potable water for cities and towns. Groundwater also infiltrates into sewer pipes from local aquifers requiring energy to pump and treat it. The Charles River and surrounding urban watersheds lose about 90 million gallons a day of clean freshwater through sewer infiltration that is ultimately discarded into Boston Harbor. Additionally, extensive development and impervious cover prevent rainwater from getting into the ground to recharge lost groundwater. Instead, rainwater runs across pavement, picking up pollutants and discharging them to local water bodies. Every year, about 20 inches of rain that should be infiltrated becomes polluted stormwater runoff. Climate change is increasing the frequency and intensity of large rain events, leading to increased polluted runoff, flash flooding and severe flooding. Continued use of fossil fuel based energy sources is exacerbating this devastating global problem.
We propose a full scale transition away from centralized wastewater treatment and energy generation to a connected, distributed, smart network of Community Water and Energy Resource Centers (CWERCs). Individual CWERCs will treat small volumes of wastewater (< 5 million gallons per day (mgd)) while maximizing wastewater resources extraction. Products such as electricity, thermal energy, nutrients, and compost will be produced from wastewater and organic food waste, two readily available, reliable, underutilized renewable energy resources. These products will be used locally to support surrounding businesses and residents, and local food production. A networked system will provide continuous energy coverage despite disruptions at a single CWERC, such as during a catastrophic weather event, providing a far more resilient system than our present day centralized structure.
Local municipalities or water authorities will construct and manage the CWERCs, sharing resources and technical expertise across the network of facilities. Legislation will need to be passed to allow these entities to sell the energy and water they produce directly to customers at reasonable and consistent rates. Initially, CWERCs will utilize existing infrastructure, mining wastewater from the existing collection system and using existing water treatment facility sites (large treatment works, pump station, etc.) for siting and development. Overtime, infrastructure can be upgraded with modern materials to reduce infiltration and inflow of clean groundwater into the sewer pipes, and consolidated into accessible infrastructure conduits with new fiber optic cables, microgrids, district energy loops and other new infrastructure.
Technologies are available today that can extract energy, compost, clean water and nutrients from wastewater and organic waste. Some of these are time tested technologies while other are new and cutting edge. Technology selection will be an important part of the community planning process in individual towns and neighborhoods. The important thing is that these energy sources are non-fossil fuel based and can immediately begin to replace natural gas and oil.
A portion of the treated water will be returned to the natural environmental to offset the impacts of human infrastructure. This could take many forms, for example, treated water could be used to recreate streams and wetlands destroyed by development, but that are critical to a region’s environmental health. Alternatively, in some areas this may mean using treated effluent to recharge groundwater levels depleted by groundwater pumping or by infiltration and inflow of clean groundwater and rainwater leaking into wastewater pipes and becoming contaminated. Restored streams and wetlands will allow the landscape to function as nature intended while providing resiliency during extreme rain events and helping to mitigate impacts of the urban heat island effect. Healthy groundwater levels that are regularly replenished will provide resiliency during extended periods of drought to support both human and aquatic needs.
Through the sale of energy, nutrients, reclaimed water and other products, CWERCs generate income which offsets the cost of operations and capital upgrades. In greater Boston we have some of the highest water and sewer rates in the country so the ability to reduce and stabilize these rates has important economic implications for rate payers. A CWERC that treats 2 mgd wastewater and takes in 80 wet tons per day of food waste could bring in an income ranging from $5.8 to $8.5 million depending on tipping fees (fees paid by food waste haulers to dispose of their waste), energy resale rates, compost/nutrient sales, and water resale rates. This does not include any potential income from wastewater treatment fees. The annualized capital cost of such a plant could range from $4.0 to $4.8 million depending on the need for onsite wastewater storage, based on a 25 year life and 7% borrowing rate. Operations and maintenance costs are estimated around $4.9 million annually. This CWERC would have an annual net operating cost ranging from $1.2 to 3.1 million to cover with wastewater treatment fees. This CWERC treats 730 million gallons annually, or more based on the incorporation of storage, therefore wastewater treatment fees would be a fraction of current charges, ranging from roughly $1.75 to $4.30/1000 gallons treated. Boston’s current rates are in the range of $8-10/1000 gallons. Additionally, a single plant would result in an annual CO2 emissions reduction of roughly 17 million pounds. Replacing our existing centralized system with a network of CWERCs could reduce CO2 emissions by 1 billion pounds annually.
There are many barriers other than financial ones to implementation of such a proposal. Initially, it is likely that individuals may oppose such a facility in their neighborhood so siting may be a challenge. CRWA has already met with numerous individuals and community groups to discuss the proposal and respond to questions and concerns. It is important that CWERCs are an asset to a local community and that designs incorporate local needs. For example, CWERCs could facilitate and power new low or middle income housing in housing constrained cities. CWERCs could co-locate with food production facilities such as urban farms or aquaculture operations to spur local initiatives.
Permitting these new facilities will also be a challenge as they do not fit into the existing model of a wastewater treatment, water treatment or energy generation facility. Permitting and oversight issues will likely be slow in initial pilot implementations. Finally, a challenge faced by the water industry as a whole is the need for trained and licensed operators. CRWA looks forward to addressing many of these issues through the thoughtful implementation and study of a pilot CWERC.
Who will take these actions?
CRWA is forming partnership across the country to investigate opportunities for implementation. CRWA will work with local governments, water authorities or potentially in a pilot scenario a private developer to conduct an onsite feasibility assessment and preliminary design. CRWA is already working locally with regulators to discuss some of the permitting issues that will arise around this proposal. As the state of Massachusetts looks to move toward more integrated planning efforts a project like this could be a preferred design standard, facilitating fast track permitting. Local municipalities or water authorities will construct and manage the CWERCs, sharing resources and technical expertise across the network of facilities. Private businesses will provide state of the art equipment to transform these “waste” products into resources, maximizing every input and ultimately creating closed loop or balanced systems. Environmental groups, landscapers and residents will need to be engaged in planning all aspects of the project and particularly in designing the restoration of the local water cycle.
Where will these actions be taken?
CRWA has done extensive investigations of the Smart Sewering concept in greater Boston. We are presently is actively working to implement this transition in conjunction with both local and national partners through construction of a pilot CWERC. This tool can be adapted to address the challenges of any urban area. This proposal has the potential to restore urban environments across the globe.
How will these actions have a high impact in addressing climate change?
One CWERC treating 3mgd of wastewater is expected to reduce 60,818,600 pounds of CO2 annually. Replacing our existing centralized system with a network of CWERCs could reduce CO2 emissions by 1 billion pounds annually. Reductions are due to local management of organic waste, and offsets of conventional electricity and thermal energy sources. While Greater Boston’s Deer Island Wastewater Treatment Plant produces some energy from wastewater, not all sources are utilized and a considerable amount of thermal energy is lost in transition. Small scale CWERCs capture and utilize the energy close to the source, reducing transmission losses.
CWERCs will help us become significantly more resilient to climate change. Reusing treated water in our homes and to recharge groundwater levels will help us sustain environmental and human water resources. Green infrastructure, such as wetlands and restored streams, create an absorbent landscape more readily able to adapt to changing precipitation patterns.
What are other key benefits?
In addition to reducing greenhouse gases, CWERCs also reduce criteria pollutant emissions such as NOx and SOx. The green infrastructure systems developed to restore the natural water cycle also have numerous societal benefits such as also reducing energy demand and CO2 emission, mitigating impacts of the urban heat island effect, carbon sequestration, habitat restoration and creation, sustainability of river systems and drinking water sources through groundwater recharge, and drastically improved stormwater management resulting in reduced flooding and improved water quality. Finally, if treated effluent is used to recharge groundwater levels in Boston's Groundwater Conservation Overlay District, nearly $23 million can be saved in underpinning costs if groundwater levels are held at a level that prevents wood pilings from rotting.
What are the proposal’s costs?
Transitioning to a new and improved infrastructure system will have costs. Each CWERC costs roughly $50 million to construct and $5 to $7 million for operations and maintenance which is offset by an income ranging from $5.8 to $8.5 million from product sales (excluding wastewater treatment fees). The associated green infrastructure represents an additional cost. Between 2014 and 20153, the Massachusetts Water Resources Authority (MWRA) plans to spend roughly $2.5 billion on capital improvements and roughly $65 million annually on operations and maintenance at the Deer Island Wastewater Treatment Plant. Additionally, MWRA spends roughly $28 million annually on potable water operations and maintenance, introducing reuse water at CWERCs could potentially reduce this by roughly 30%. Transitioning away from the centralized system to a distributed network of approximately 100 CWERCs would alleviate the need to spend much of that $2.5 billion in planned capital upgrades, could results in reduced users fees, while also providing significant societal and environmental benefits.
In the short term, individual plants will be built as pilots to test and refine the system. In the medium term, we will implement the full transition from the Deer Island Wastewater Treatment Plant to the distributed network of CWERCs.
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