Development of a Cost-effective, Nutrient-removal, Onsite Household Wastewater Treatment System for Environmentally Fragile Areas

Coastal communities have witnessed their ecosystems change over the past 25 years due to nitrogen loading and phosphate pollution from high-population density and no access to centralized sewage systems. Some effects have been eutrophication, algal blooms, fish dying and, most notably, consequences for local development and real estate.CLEW provides an inexpensive, efficient and an environmentally friendly solution for total onsite wastewater treatment that can be independent of existing energy and sewer infrastructure. For a cost-effective price of $12,000 (installation included), the CLEW SystemTM can reduce the nitrogen loading to 5 mg/L or less and avoid surface water and soil contamination while producing valuable by-products such as hydrogen and fertilizers. CLEW has developed an onsite wastewater treatment unit that can be powered by solar panels or connected to regular electrical grid. This system consists of a series of holding tanks and electrochemical reactors. Once the wastewater is disinfected and has a reduced nutrients loading, it can be safely reused as flushing water or leached out without detrimental impact on the environment. In the United States, 26 million households are equipped with septic tanks, ten percent of which are located in environmentally fragile ecosystems. The CLEW systemTM can bring a solution to septic-based pollution in coastal communities where EPA recommends stringent Total Maximum Daily Loads in nitrogen, phosphorus and sediments, such as Cape Cod in Massachusetts or the Chesapeake Bay. CLEW will propose a standard septic tank replacement unit that can be directly connected to the household sewer line. Customers are willing to invest $5,000 to replace their septic tank unit. The remaining part of the installation cost will be covered by a lease system and with the eventual help of tax incentives. For new households, CLEW is partnering with architects to determine the best space/fitting. CLEW will also require a monthly contract with customers to maintain and service the units. The innovative septic system presented in this proposal is the direct application for a U.S. market of the self-contained, sun-powered electrochemical wastewater treatment system developed by researchers at the California Institute of Technology for the Bill & Melinda Gates Foundation ($2.2 M for 2012 and 2013). This system was awarded the first prize at the Reinvent the Toilet Fair organized by the Gates Foundation in August 2012.