Environmental planners and Agronomists have been encouraging states and countries to embrace urban agriculture to increase food production. The increase of global human population in the past few decades, as well as climatic change, indicates that food scarcity might be a threat to humanity before 22nd Century. The food crisis has been evidenced in various developing countries, and urban areas being adversely affected. Therefore, urban agriculture can be one of the lasting solutions to boost food production.
Given the enormous generation of compost in cities and towns, it can be processed and used in both public and private farms. Compost is generally green because it has no harmful chemicals that can cause complex disorders in human bodies. It is also environmentally friendly because no contaminants that can pollute our water sources.
Composting toilets are of many types, but can be classified into two categories; Batch-type and continuous systems. The batch-type units are the most popular self-contained toilets that have several bins, but the under-floor space is not required. When one bin is full, it is moved to a different place so that full composting can take place. Composting period may go for a few weeks, usually 5 to 6 weeks. When the composting process is complete, the content is buried and the empty bin replaces another full one.
The continuous systems, on the other hand, have a single chamber where waste materials are collected. The chamber stores the waste until composting process is complete. However, this system is different from the batch-type units because an under-floor space is needed. It is expensive to design these systems and difficult to plan for several toilets.
The Green Benefits
An average city resident uses about 280 liters of water on daily basis, and almost one-third of that amount is flushed down the toilet. As per the comprehensive research by PickaToilet; for homes that have even the best flushing toilets may use up to 26 liters in every flush. That is why many state laws are recommending the use of modern toilet models that use about 6 liters per flush. These are known as low-flow toilets, which help save water usage in homes.
However, composting toilets are more efficient when it comes to water saving. A typical composting toilet can save more than 24,000 liters of water per year. Eliminating water usage for flushing can help reduce energy consumption in septic systems and treatment plants. This is also a big benefit when it comes to addressing pollution in water sources. Note that, most of these liquid wastes are deposited into waterways making them unable to habitat animals and plants.
Urban agriculture can be executed easily through the application of organic manure from the composting toilets. Even though the liquid wastewater removes oxygen in the water, it can form nutrient rich humus when put back into the soil. It also neutralizes toxins in the ground and boosts microbial action that reduces disease-causing germs. Some pathogens may survive in the humus, but your compost can be laboratory tested to know the extent of pathogen levels. If there is disease causing microorganisms, the humus cannot be used to produce vegetables for human consumption.
If you want to build a self-contained batch-type toilet, ventilation is vital to keep away bad odor and enhance oxygen supply for the compost material to break down. This can be well achieved through the use of electricity-powered heaters and fans. A minimum temperature is required for the compost to break down easily and faster. For those residing off the grid, the heater may need more electricity than what you normally use in the house. However, you don’t need to run the heater throughout the day and night – 6 hours are enough every day.
Batch-type composting toilets are small and could potentially use minimal power for fans, ranging from 80 to 150 KW. This is a small amount of power, almost equal to the power used by a lighting bulb. If you have installed solar panels in your home, the ‘free’ energy can be used to power the heater and fans. However, you should not forget to consider the maintenance costs. This is very important because the composting toilets are managed and maintained by specific individuals that are already familiar with that job.
In conclusion, the use of composting toilets is a green investment that can facilitate clean urban agriculture. But, improper maintenance can be the root cause of failure because few people are willing to interact with their feces once they get out of their bodies. So, someone is needed to manage the composting system adequately.