Some years ago, while sailing in the San Juans, I noticed that the sea life was dead where Orcas Island sewer effluent empties into the sound. This “dead zone” is apparently our small contribution to a widespread condition of inadequate dissolved oxygen in the sound, a problem caused by excess nutrients which cause too much plant and algae growth; this ultimately depletes dissolved oxygen when the plants die. According to the Department of Ecology, many parts of Puget Sound now have oxygen levels below what is needed for marine life to thrive – and below levels required by the state’s water quality criteria.
Our current sewer system also doesn’t affect disease organisms, pharmaceuticals or fertilizers. They pass through to the ocean. The present system was the best approach at the time it was implemented. But, with improved technology, there is a better solution now.
A friend recently shared a Youtube video showing a village in India where people defecated on the ground, contaminating the groundwater and creating a public health problem. A Connecticut company, Biomass Controls, brought a device to the village, a digester that converted fecal matter to biochar. This ended the water pollution problem and produced a product that can be put on vegetation or sold at a profit. Biomass Controls offers a digester that is a suitable size for a population of 15,000. It runs 24 hours a day and creates 18 pounds of biochar per hour. The machine comes in a 40-foot container, sets up in two days, and costs $400,000.
Its advantages over the current system include: Due to the high temperatures involved in the process, all disease organisms and organic toxins are destroyed. Pharmaceuticals are also rendered harmless. It creates a valuable product for soil amendment. The product is also potentially marketable. It retains water-borne nutrients, reducing water and fertilizer usage.
It reduces global warming by locking up carbon. It eliminates the negative effects of effluent on ocean life. Once the digester has produced the first batch, it uses its own generated methane as the energy source to dry out the next batch and creates electricity that can be sent back to offset grid energy usage. A potential drawback of biochar based on human waste is the presence of heavy metals. This could necessitate composting, or require using the biochar on forests rather than gardens. Eastsound should study the feasibility and potential cost-savings of implementing a system like this.