WANDEGEYA, UGANDA—When I was buying fries in the fastfood/street food district near Makerere University where I have been staying I noticed a sewage truck. Mohammed the driver explained what was going on. The 7 inch sewer that services the restaurant area gets clogged several times a week. The unclogging responded to sewer overflow complaints on Christmas Eve, Christmas Day and now they were back on Monday, two days after Christmas. The sewer is undersized for the population it serves but that is not what causes the blockages. The restaurants and food stands in this area dump their Fats, Oils and Greases (FOG) down the drains that empty into the sewers. See below for what grease does to a sewer.
Above are photos take of a London sewer before and after the rancid Fats, Oils and Greases were cleared away. The same applies to all sewers of the world so now you know what happens when you dump grease down the drain. Now imagine the impact on the 7 inch sewers of Kampala compared with the one meter sewers of London.
The team of about 9 men blasted water down the triangular sewer cover to unclog it. The water from the sewer overflowed (see the puddles above) and formed a stream going through the parking lot of the restaurants. Eventually their truck ran out of water and the sewer was still clogged.
It is a shame to waste FOG. It contains energy that we could use to our advantage instead of letting it clog our drains. I remembered a company called Black Gold Biofuels based out of Philadelphia that turns FOG into biodiesel and has won much acclaim recently. I went to an internet cafe to see what else can be done with FOG. I discovered studies showing that FOG can be used as a substrate in anaerobic digestion to produce biogas (methane) as well.
The BIG Picture Here is another waste that costs the city a lot of time and money when it could be a resource. An inefficiency is an opportunity. And there are so many stakeholders to benefit from a solution.