The challenge of water scarcity motivated us to develop innovative water treatment solutions and prioritize water reuse wherever practical. At our institute, we generate two types of wastewater: graywater, originating from the kitchen sink and bathroom fixtures (washbasin and shower), and black water, which comprises wastewater from toilets. From the inception of our project, our aim was to recycle graywater for irrigating our institutional garden. To achieve this, we had to establish a clear separation between gray and black water.
Let’s commence by detailing our approach to black water treatment, particularly the treatment of human waste. In our quest for efficiency and ecological sustainability, we embraced the concept of composting toilets. The most basic setup of a composting toilet involves a bucket filled with sawdust or another carbon-rich material capable of absorbing moisture. Conventional composting toilet designs segregate liquids since they are unsuitable for the composting process. However, to maintain the level of comfort expected at our institute, we opted for a standard ceramic flushing toilet. We found a solution in a concept called the vermicomposting toilet, which combines the benefits of composting with the convenience of a standard flushing toilet.
For those interested in a comprehensive description of the vermicomposting toilet system, we recommend referring to the thorough explanation available elsewhere (https://www.earthwormsoc.org.uk/VermicompostingToilets). Here, we provide a brief summary of our adaptation of this system.
We constructed the underground vermicompost from a repurposed 1000-liter IBC tank. Within the tank, we inserted a 10cm diameter pipe with holes drilled throughout its length to prevent waterlogging and ensure the well-being of the earthworms. To maintain a suitable environment for the earthworms, it’s crucial to supplement the vermicompost with other organic wastes, not limited to toilet waste. Materials rich in carbon, such as sawdust and small branches, play a key role. We also enrich the compost with organic waste from our garden and kitchen. In 2021, we initiated the operation of the vermicomposting toilet system with the introduction of the initial group of settlers from the species Eisenia fetida. After two years of operation, we’re delighted to report that our vermicomposting toilet system has become a haven for earthworms, and every visitor to our institute eagerly contributes to supporting our little helpers.
One of our initial ideas was to reuse gray water also for flushing the toilet. We left from this approach later on as the water full of organic waste from kitchen sink start to spoil very fast in the toilet and also in toilet water reservoir producing unwelcome smell. Thus nowdays all the graywater goes directly to three chamber septic with volume of 3000 L. Here all the organic vastes in anerobic conditions undergoe the procesing by bacterias. And at the end the graywater is reused for water the garden.One of our original concepts was to utilize gray water for flushing the toilet. However, we later abandoned this approach due to the rapid degradation of the water, filled with organic waste from the kitchen sink, which caused unpleasant odors in the toilet and its water reservoir. Nowadays, all gray water is directed to a three-chamber septic tank with a capacity of 3000 liters. Within this system, organic waste undergoes anaerobic processing by bacteria. Ultimately, the treated gray water is repurposed for irrigating the garden.”
