The global mindfulness of the phenomenon of climate change together with the anticipated scarcity of conventional energy resources have prompted many countries around the world to develop a more sustainable energy systems to cater for development and growth.
Renewable energy provides a safe and feasible option for the provision of a clean and environment friendly energy. In line with broad international consensus and the policies of most developed countries to embrace RE resources as a better source of energy, Waste water according to the SmithGroupJJR research team is a secure and economical source of renewable energy for the next generation of green buildings. The most important factor realised by this team is that this energy is easily accessible i.e. It already flows through pipes right beneath our feet.
According to Don Posson (a representative of the group), Lexicographers trace the old saying “waste not, want not” back to late 18th century England but it took the engineers a couple of centuries to catch on and finally embrace a literal interpretation of the adage. The research observed that as much as 40 to 50% of a building’s energy literally goes down the drain every day. When the water we heat for cooking, cleaning, bathing and washing our clothes, among other uses, enters a sewer system, it helps to heat the wastewater flowing through that system to an average temperature of 60-70 degrees F, thereby creating a stable, flowing geothermal source of energy that until now has been wasting.
The question is: what if the wasted energy could be recovered and recycled back into our buildings for heating and cooling purposes? The Washington DC Water’s new state-of-the-green-art headquarters on the banks of the Anacostia River in the southeast is set to make this work in 2018.
IT IS TIME for the Nigerian Government to rethink its own energy policies. There exists a vast biomass potential in the form of biocrops and fuelwood, biogas, wind, solar and small hydro in Nigeria, albeit being grossly underutilized.
As observed in quite a number of successful countries in promoting RE such as Denmark, Germany, USA, China and Japan, a strong and long-term commitment from the government is crucial in implementing any kind of policies which will lead to efficacious renewable energy development.
The initial research by the Skanska + SmithGroupJJR team indicated that there were two types of technology in use around the world to convert the waste water into energy:
1. in-line systems with underground energy exchange piping systems, and
2. Off-line systems utilizing pumped wastewater and above ground heat exchangers.
This technology is comparatively simple and cost effective. The process is similar in both cases. Raw wastewater passes through a separator, which removes solid waste and sends it back to the sewer. The liquid waste then passes through a heat exchanger, which extracts its thermal energy to heat a separate stream of clean fluid. The heat-depleted wastewater returns to the sewer, while a heat pump distributes the clean fluid throughout a building in much the same way as a conventional boiler and radiator system works.
The difference is that in-line systems install exchangers on the invert side of the sewer pipes themselves, which requires pipes with a larger diameter than those found in most existing and older municipal sewer systems. In those systems – with Washington, DC being a case in point—a building’s wastewater is first collected in a well or pit before being pumped through a conventional heat exchanger equipped with a filtering system to separate solid and liquid wastes.
This technology is a breakthrough that the Nigerian energy systems can adopt and put to good use. The technology produces a lot of biogas which is a bacterial decomposition of organic matter in the absence of air, by the biodegradation of organic material under anaerobic conditions. Some of the biogas raw materials are animal dung, industrial wastes, household wastes and air dry crop residues. The mixture of different types of wastes produces more biogas energy.
Biogas is practically suitable for a variety of applications in the agriculture, household and industrial sectors. Its utilization instead of diesel, fuelwood, charcoal, and kerosene reduces GHG emissions. In addition, it exhibits no risk to health; does not have offensive odor and it burns with a clean bluish, spotless flame thereby making it non-messy to cooking utensils and kitchens.
Identified feedstock substrate is considered an economically feasible biogas program in Nigeria that includes dung, water hyacinth, cassava leaves, solid (including industrial) waste, water lettuce, urban refuse, agricultural residues and sewage.
Nigeria produces about 227,500 t of fresh animals daily and regrettably, renewable energy resources are presently disregarded from the energy supply mix in Nigeria, and yet have a modest share in future energy plans, albeit having a remarkable potential. This may lead to a risky situation of falling into a fossil fuel trap. With the near depletion of the fossil fuels in Nigeria, the prospect of sliding into a severe energy crisis seems inevitable.