Can we recycle human waste into a useful resource?

12.09.2019 Water & waste

In the national sanitation survey in Bangladesh in 2003 it was observed that only 58% households had some form of latrines whereas the remaining 42% of households had no latrines at all.

With a special compost from human wastedrive undertaken by the Government of Bangladesh and development partners with the active engagement of local government institutions and communities, sanitation progress gained momentum with a focus on building different types of low-cost pit latrines. As a result, the open defecation rate has been reduced to less than 3%. But does this mean the problem has been solved? Not really, rather a second generation sanitation problem has emerged in Bangladesh.

In this country, about 80 metric tons of human waste is generated every day of which only 960 tons is treated at Pagla treatment plant – only about 1%. The question is what happens to the remaining waste?

Less than a quarter of Dhaka city area has a sewerage network. In Dhaka, where there is no sewerage network, more than half of the buildings do not have any proper septic tanks and the sewer pipelines of these buildings are directly connected to either the open drain or to the storm drainage system polluting the surface water and the environment. A huge number of pit latrines exist in rural areas and low income urban communities. Due to the rapid expansion of low-cost latrines, pits fill quickly and require frequent emptying. Even septic tanks (not connected to sewerage network) require emptying at longer intervals.

Growing vegetables with human-sludge-compost is used as manure

 

Interestingly, people in general are not aware about how this waste is disposed and how it impacts the surrounding environment. There is no proper emptying mechanism for pits or septic tanks. In most cases, it is done manually by sweepers when the problem becomes visible by overflowing or creating nuisance. The sweepers dilute the substances with water mixed with kerosene oil and dump it manually to the nearby open drain. Mechanical suction devices such as vacutugs are rarely used and when they are used, they dispose the human waste into open drains or nearby ditches. Current waste removal practices invariably pollute the shallow aquifer.

 

 

The country has put enormous emphasis on promoting low-cost latrines without thinking of waste management. Recycling of the human waste by converting it into proper organic fertilizer would be one practical solution. Bangladesh uses around 3.5 million tons of fertilizer every year of which about 2.6 million tons are imported. Government provides a subsidy of around 18 taka (15p) per kg of fertiliser to  farmers. Hypothetically if we could convert the entire amount of human waste produced in the country into organic fertilizer, it will make 3 million tons which will be more than the amount we import every year. Even if we could utilize a certain percentage of this potential, it would be a huge gain for the country. However, this should not only be considered from a monetary perspective; use of this fertilizer will improve soil texture and most importantly, prevent surface water pollution.

vegetable field human-sludge-compost used as manureRecently different actors have shown interest in human waste management and are experimenting on several small scale initiatives. Unfortunately there is no proper human waste management value chain in Bangladesh. Creating awareness among the masses and sensitizing them to their roles as citizens are critically important along with clarifying the roles of the city authorities. Emphasis should be given to introducing technologies in different country contexts and promoting the use of organic fertilizer. Entrepreneurship should be developed for collection and transportation of waste. Most importantly actors like department of agriculture, agricultural universities, research agencies and private sectors should introduce standardization of organic fertilizers and explore marketing strategies for the products. However changing the mindset of the people and the policy makers remains a challenge.