WASTE & ENERGY PRODUCTION
Waste to energy (WtE) or energy from waste (EfW) is the process of generating
energy in the form of electricity and/or heat from the primary treatment of waste, or
the prepossessing of waste into a fuel source. WtE is a form of energy recovery.
Most WtE processes generate electricity and/or heat directly through combustion,
or produce a combustible fuel commodity such as methane, methanol, ethanol or
synthetic fuels.
Household Waste:
Iraq produces around 30,000 tons of solid waste every single day of which around
7,000 tons are generated in the Kurdistan Region. The country lacks real waste management infrastructure to dispose of this waste in a proper way that ensures no negative environmental or health effects. Most of it gets disposed of in unregulated landfills where spontaneous fires, groundwater contamination, surface water pollution and large-scale greenhouse gas emissions are accepted as normal.
Decomposing waste in landfills produce a number of toxic chemicals including ammonia, sulphides, methane, and carbon dioxide. Ammonia and hydrogen sulphide are responsible for most of the odours while methane is flammable and concentrations can sometimes exceed explosive levels if trapped inside structures. Methane and carbon dioxide can collect in nearby buildings and displace oxygen providing a potential hazard to humans. In addition to this the usual method to reduce waste on these sites is by burning which releases more toxins into the air along with dangerous soots and particulate matter all of which threaten the health of neighbouring populations.
Current practices end up costing Iraq a high price when it comes to its commitments to reduce greenhouse gas emissions in addition to all the pollution of soil, groundwater and local environments they directly cause. The recyclable components in this waste such as metals and plastic can be removed and combustible material incinerated to create steam for feeding into a turbine which in turn is connected to a generator producing electricity. An air-pollution control system removes pollutants from the combustion gas before it is released through a smoke stack.
The UAE is leading the way with the opening of a power plant in Sharjah as part of the Emirates Waste to Energy venture – the first of its kind in the Middle East. This facility is expected to divert 300,000 tons of waste from landfills yearly and generate 30 megawatts of electricity. This will be enough to power 28,000 homes in Sharjah annually, the UAE’s third largest city.
The government of Iraq has now introduced a law to support the use of solid waste for the production of electricity and methane gas which aims to encourage investment in the production of these resources. The Environment Ministry is working on this as part of government strategy that plans to deal with a steady rise in power consumption and reduce energy imports.
Leading the way in 2021 Eggersmann Group partnered with Faruk Group commissioning the Middle East’s first RDF (refuse-derived fuel) bio-drying project in Sulaymaniyah, Iraq. The plant receives in excess of 1,000 tonnes per day of MSW (municipal solid waste) and commercial waste. The RDF is used in the group’s own cement plant. This large-scale project also includes a sanitary landfill with leachate collection for the processing residues.
Solid waste collected by the municipality combined with commercial waste from the local industrial area had been dumped without any treatment near Tanjaro River in southern Sulaimaniyah City causing extreme levels of environmental pollution.
This facility is capable of processing 1040tpd (tonnes per day) of municipal solid waste, reaching an overall landfill diversion rate of more than 80 per cent. Faruk Group negotiated a 20-year agreement for receiving waste from the municipality at an agreed tipping fee per tonne.
With this Sulaymaniyah facility as an example it proves civil society and the local municipality can rely on an affordable solution to fight waste accumulation in landfills and groundwater contamination. The cement producer receives reliable quality of RDF, reducing fossil fuel dependency, energy cost and CO2 emissions.
Sewage:
Sewage outlet pipes are crowded alongside the Tigris and Euphrates rivers and their tributaries in most of the Iraqi provinces causing catastrophic environmental
pollution. The dumping of raw sewage directly into the Tigris and the Euphrates rivers is an ongoing environmental disaster. Over 5 million cubic meters of sewage and effluent is dumped daily into these rivers resulting in pollution and disease. Baghdad is the largest source of pollution to the waters of the Tigris where 18
sewage stations pour untreated effluent into the river at a rate of 700,000 cubic meters per day. This combines with commercial and medical waste offloaded into the rivers meaning the pollution index in the rivers rises day by day.
While these major cities and urban areas require monumental investment programmes to overhaul the infrastructure, on a smaller scale there are many proven and effective processes that can be adopted now to transform the bulk of this waste into a useful resource. Through anaerobic digestion it is possible to produce biogas as methane and high quality fertilizer from the organic material. The biogas can be transformed into electrical and thermal energy by means of cogenerator (CHP – Combined Heat & Power). New projects should be initiated using this relatively simple technology to harvest methane emissions from the biological digestion processes, the gas can be used not only to generate power for the sewage facilities it can be fed into the local grid. While this is ongoing natural treatment systems can be introduced to mitigate the immediate threat of dumping sewage into the waters and supplement longer-term sewage management efforts. These natural-treatment schemes are not as efficient as modern sewage-management mechanisms and can’t process the volumes produced by large cities but they would nonetheless improve water quality and allow it to be safely reused for agriculture or recharging the aquifer
across less densely populated districts. A reed bed or constructed wetland has proven to be an effective, sustainable, reliable, and economical treatment method for sewage or industrial waste.
The reed-bed treatment systems in desert area 103, Libya, are self-contained, artificially engineered wetland ecosystems. They are designed to optimize the microbiological, chemical, and physical processes naturally occurring in a wetland. The reed-bed wastewater treatment plant in desert area 103 is the first wastewater treatment facility in the Libyan desert oil fields. It can treat up to 350 m3 of wastewater effluent per day using automatic submersible pumps. The reed bed is lined with plastic sheets underneath the gravel to prevent effluent from seeping underground. Wastewater is discharged to the reed bed for treatment after primary tank screening and settling. Wastewater is gravity fed into the reed-bed and directed to run over local stones and rocks which begins the bio treatment process. The common reed used is Phragmites australis, indigenous to the Libyan desert 103 area. It has the ability to transfer atmospheric oxygen from its leaves down through its stem, porous septa, and rhizomes, and out into the rhizosphere (root system).
These aquatic plant based systems allow bacteria, fungi and algae to digest the organic matter in the effluent. The best system often results from a combination of vertical and horizontal flow reed-bed. Inn each case the effluent percolates through layers of sand and gravel in an enclosed bed. The resulting liquid is clean enough to filter into the groundwater. The reed-bed wastewater treatment project in Libya improved the scenery and odour of the wastewater area, protected the water well in the middle of the camp and the water table, and reduced the ecological impact on the endangered wildlife in the area.
These schemes can be implemented quickly in villages and towns particularly across rural areas where they would be ideal as well as in medium-sized cities with agricultural lands in their vicinity.
Energy from sewage:
While typically seen as a nuisance, the organic matter contained in wastewater sewage systems, or ‘sludge’ is actually a valuable resource with a significant amount of potential renewable energy. Biogas rich in methane can be extracted from this and used for generating electricity, releasing far less CO2 than when fossil fuels are burnt. In addition, the solid remnants of the waste create a nutrient-rich “digestate” that can be utilised as an effective fertiliser.
In conventional waste treatment the initial treatment stages involve the solids being removed through screening, sedimentation and skimming. Then flows are reduced to encourage further sedimentation. All the subsequent solid matter either scraped from the bottom or surface skimmed produces this sludge. To produce a usable biogas in a sludge-to-energy system, this sludge then undergoes a pre-treatment process know as thermal hydrolysis which exposes the sludge to high temperatures and pressure thereby maximizing the amount of gas it can produce. Next, the treated waste enters an anaerobic digester, and kept at 35c which finishes breaking it down. The resulting product is a methane-rich gas, or biogas, that can be used for on-site energy needs such as electricity generation to maintain a constant working temperature in the digesters. This means the
facility can become energy self-sufficient efficiently meeting its own energy needs. Any excess electricity production can be diverted to the local grid for nearby communities to supplement their supplies.
The remaining biosolids or digestate, can be exploited as a rich fertilizer containing valuable organic matter and nutrients such as nitrogen and phosphorus. When applied to land at the appropriate agronomic rate this material provides a number of benefits including nutrient addition, improved soil structure, and water reuse. Recycling these biosolids from the wastewater treatment process to use in agriculture is one of the most sustainable options. It also acts as a high-quality alternative to manufactured chemical or synthetic fertilisers, along with the associated cost savings.
