**4.1 Uganda's waste generation and management**

Uganda's current waste management system involves both the private and public sectors and that the estimated solid waste generation rates for Uganda range between 0.55 and 0.6 kg/person/day [46–48]. The respective generation rates were based on studies done on Kampala district and Mukono district, respectively but this could be comparable to other districts. Further, a study revealed that waste generation rates in Uganda are 0.3 kg/day for low-income homes, and 0.66 kg/day for high-income homes and that the domestic (residential) sector of the country contributes 52% (ref. **Table 1**) of the waste generated [49]. However, this study was carried out from only the 9/15 of urban cities from the political-administrative regions of Uganda.

The different sectors generate mainly organic wastes (food waste) and the dry wastes are the minor forms of waste. Also, the waste composition of the industry sector varies depending on the type and all this data is illustrated in **Table 1** [49]. Results in


#### **Table 1.**

*Waste in Uganda.*

**Table 1** are relative to a study carried out, by Okot-Okumu [46], to assess waste management in three significant towns in Uganda (Kampala, Jinja, and Lira) which revealed that the biodegradable composition of waste was higher that is 77.2, 78.6, and 68.7%, respectively. Also, a study [50] discovered that Kampala generates up to 28,000 tonnes of waste/month with an organic composition of 92.1% while plastic and paper account for only 5.9%. The reason for the difference could be that the former [46] examined solid waste from its origin to final dumping and was carried out using existing publications and reports while the latter [50] was carried out through sampling, field measurement, and laboratory tests of waste disposed at the Kiteezi landfill in Kampala for a year (July 2011–June 2012) to obtain the chemical composition. Nonetheless, both studies could imply that waste in Uganda mainly comprises of organic waste.

The most sought-after way of collecting waste is when waste producers move their waste to community collection sites such as bunkers or skips, and the waste is taken to landfills by the respective municipalities. In some cases, the private sector waste management companies collect waste from house to house but this is normally at a fee, or the larger institutions and commercial businesses hire the private companies to handle the waste [46]. It was found that communities with bad road access are avoided by collecting trucks which leads to high rates of open dumping as a means of disposal by the waste producers [50]. Also, reports point out that apart from poor road access, unaffordability when a waste collection fee is required is another cause of poor solid management [51]. Most of the urban areas in Uganda have waste released in gardens, along the road, open dumps, and channels. **Figure 14** is an illustration of open dumping in urban areas of Uganda [48]. Open dumping poses environmental and health risks for the respective communities through pollution of soil, and surface water, degradation of the ecosystem as well as GHG emission when the organic waste decomposes [51, 53].

Reports [54] reveal that landfilling is the only authorised form of disposal currently in the country and other forms such as open dumping, uncontrolled

#### **Figure 14.**

*A display of open dumping in Kampala [52].*

burning, relative recycling, and composting which take place at unknown extents. Also, 40–45% of waste generated is gathered and thrown away to the landfills and that 11% is recycled by waste pickers [50, 51, 54]. This is comparable to a report that indicates 50% generated waste is collected. For Kampala city, all the waste collected is usually dumped on one landfill, Kiteezi, which is about 12 km from the city centre [50, 55]. This landfill is a sanitary landfill occupying 0.146 km<sup>2</sup> of land with a leachate treatment system that decreases the biological oxygen before the leachate is discarded to the nearby wetland. Despite this initiative, residents around complain of bad odour, leachate leakages, and increased scattering of wastes by marabou stocks causing their land to lose value. Also, the openness and mismanagement of the landfills cause a problem of air pollution through GHG emissions which pose a health risk [46, 50].

The 2010 audit report for SWM in Kampala credits the inefficiencies in waste management to the lack of awareness which has led to aimless littering and uncontrolled burning of waste [56]. A study [46] points out that the record of waste collected accounts for that which reaches the community collection points and the uncollected waste is not recorded. This could be problem when identifying suitable management techniques due to insufficient waste data.

The mentioned studies are specific to just a few cities in the country with a major focus on the capital city Kampala. However, it is plausible to conclude that majority of waste produced in Uganda comprises organic waste with an overall composition of above 70%. This could also be assumed since the major economic activity is agriculture which is usually associated with organic waste.

A study [46] reports that the majority of the waste is mixed and there is no official structure of sorting waste in the country. Sorting may happen when workers segregate wastes of value on the way to the landfills or at the waste bunkers, road verges, skips, or at the landfills and this is illustrated in **Figure 15**. Most wastes hand-picked are plastics comprising of jerry cans, and bottles as well as cardboard. In some cases, the separation is done only when the producer is looking to reuse the plastic material or glass bottles or use food leftovers as animal feeds [46, 51]. **Figure 16** is an image of plastic bottles collected for recycling.

*Evaluating Waste-to-Energy Technologies as a Waste Management Solution for Uganda DOI: http://dx.doi.org/10.5772/intechopen.101904*

#### **Figure 15.**

*Waste picker segregating waste at Kiteezi landfill [57].*

**Figure 16.** *Coca-Cola recycling plant at Kyambogo-Kampala Uganda [55].*

#### **4.2 Technology capabilities in Uganda**

The choice on which technology to adapt depends on the local conditions and energy requirements of the communities and/or sectors of a country. Because of these reasons, the Government of the UK always maintains an attitude of being technologyneutral when promoting private investment unless the technology shows evidence

of market failure [7]. Also, knowledge of the organic fraction, calorific value, and chemical composition enables a country to know how best to manage the waste [11].

Therefore, the successful implementation of anaerobic digestion in Uganda would largely depend on waste generated from agriculture and reports that the residential and market sectors generate more than 72% of the waste which largely comprises of food waste. The waste from these sectors has a high moisture content which would accelerate production of biogas.

It would be suitable to meet the energy needs of these market structures while solving the problem of food waste management. Also, in Section 3 it is mentioned that the yield of anaerobic digestion is higher when food waste is fed into the digesters along with MSW could make this technology a reliable source of energy in residential households, and markets in Uganda since they generate mostly food waste. The country could adopt large scale anaerobic digestion like the Gorge anaerobic digestion plant in Kenya highlighted in (Section 3) where the waste from farms is used to generate electricity for farm activities. In the long run, the biogas generated from large scale projects can used in the transportation sector as a source of fuel which could introduce flexi-fuel vehicles that use both petroleum and bio-methane [58].

Regarding WTE incineration, the technology is more efficient when the CV of the waste is high. Uganda's waste has a CV of 6.2 MJ/kg which is below the typical range for raw waste highlighted in Section 3 hence the country could apply the circulating fluidised bed combustion technology which permits waste with low CV. However, this type of incinerator processes lower quantities of waste compared to the grate-based combustion technology. An alternative would be to pre-treat the waste to increase the efficiency of the plant. Overall, the application of incineration would generate electricity that would meet the demands of manufacturing industries and surrounding communities to promote energy security. For example, a similar project like the Reppie plant in Ethiopia could be set up in Uganda to process waste to generate about 20 MW of electricity. Such a project is comparable because Ethiopia is reported to have waste compositions comprising of 60% organic waste [59, 60] which is similar Uganda. Also, this plant has a pre-treatment section to increase the energy content in the waste. Such a plant could process waste from Kampala which is estimated to generate 28,000 tonnes/month ≈ 930 tonnes/day [50]. Such projects could be implemented around the country to reduce the quantity of waste that goes to the landfills and to improve energy security.

In Section 3 it is noted that the incineration plant is more efficient when it generates heat or both heat and power. The heat produced may be wasted since district supply heating systems are not necessary as the country's temperatures are relatively warm throughout the year (26°C [61]) hence household or commercial heating is not required. However, the heat produced can be used for heating processes in nearby factories.

Concerning landfill gas recovery, this technology would require sufficient land to implement. In Section 3 an average landfill site occupies 600 acres but with the current size of Uganda and the high rate of population increase, the application of landfill gas recovery would be affected by shortage of land. Also, the landfill sites would have to be away from the growing cities due to the high rates of urbanisation in the country. Nonetheless, this mechanism would still be applicable in parts of the country that are less populated and have sufficient land. This would however incur costs to transport waste generated to such locations. Comparing landfills and anaerobic digestion, the former generates lower fractions of methane than the latter and so it would be advisable to consider anaerobic digestion.

#### *Evaluating Waste-to-Energy Technologies as a Waste Management Solution for Uganda DOI: http://dx.doi.org/10.5772/intechopen.101904*

Turning now to pyrolysis and gasification, Section 3 reveals that the processes are difficult to scale up hence cannot be used for large scale purposes and commercial purposes due to their complexities in fuel requirements. However, these technologies could be adopted by industries, specifically the rotary kiln type of reactor which offers the advantage proper heat transfer allowing it to process waste polymers (plastics) which have low thermal conductivity and generate the best quality oil suitable for industrial purposes. However, Uganda has low generation rates of waste polymers (dry waste) and projections indicate low dry waste generation in the next decade hence such technologies could be unsustainable in the long run.

Regarding waste as a fuel, [7] the waste needs to be appropriate for the technology in question. Reports state that the inadequacy in the supply of feedstock to biogas plants is a barrier to the technologies. This could be comparable to the other technologies [62]. Anaerobic digestion, incineration, and pyrolysis need the waste to be pre-treated through separation, sorting, processing and mixing with additives to optimise efficiency, increase the calorific values, and reduce levels of pollution [31]. In observed that fossil fuel-based wastes emit GHG which contribute to climate change, which is another reason to why waste should be separated. Literature reports that lack of waste separation has led to the failure of large-scale bio-methanation in India [63]. Therefore, Uganda would have inconsistencies in the waste fuel due to lack of separation leading to mixed wastes and this could affect the sustainability in the long run. This will also increase costs incurred by the plants to mechanically treat waste. Nonetheless, these technologies could still be adopted by manufacturing industries in Uganda which are more consistent in the characteristics of waste as per industry, for example, Kakira Sugar factory processes bagasse to produce heat and electricity.

Also, lack of separation could lead to hazardous materials in the waste which pose the risk of generating toxic chemicals in solid and gaseous residues from the processes that are later disposed of. However, Uganda has low levels of industrialisation and it would seem unlikely to have large quantities of harmful material in the waste which could make mechanical separation easier. In addition, Uganda would need to improve her collection efficiencies from 45% to the daily target of 80% to ensure the plants have a consistent supply of fuel. A study [24] claims that when technology can work with inconsistent fuels then it is feasible for such communities and in this case landfill gas recovery would be the most suitable.

Lastly it is noted in Section 3 that the different designs and configurations of anaerobic digestion require the use of water to optimise the digestion of MSW. This is a could be a major problem since reports [53] show that the availability of water is limited in densely populated regions of Uganda and that 76% of Ugandans have water within reach of 1 km. To solve this, the country could focus on using the high solid continuous digestion systems which require little water (Section 3(1)). The supply of biogas is inadequate to meet the needs of a community, they resort to the rudimentary sources of fuel [62]. This concern would be comparable to the other WTE technologies as the choice by beneficiaries to adopt any technology is most likely dependent on reliability.

#### **4.3 Policies review**

Regarding consistency, that waste-sorting has a significant effect on the efficiency of all technologies and since Uganda lacks waste separation regulations this will affect the output of the technologies which will in turn affect the revenue flows [64]. The National Environment (Waste Management) Regulations, S.I. No 52/1999 under sections 53(2) and 107 of the National Environment Act, Cap 153 [65],

shows no mandate which directs a waste producer to explicitly separate the waste generated according to physical or chemical composition. This causes a problem of delivering mixed waste that makes it hard for plants to have consistency in the physical and chemical composition of waste which could affect the sustainability of plants in the long run. A lot of effort would then be needed to sort waste before extracting the energy and these extra costs may not be attractive to investors. Also, these extra costs may lead to a rise in the cost of electricity purchased by the customers. To mitigate these, the GOU could enforce some of the UK's policies (**Table 2**) to enhance better SWM. Also, awareness campaigns through media platforms and community focus groups can help solve the problem of waste segregation to improve the efficiency of WTE initiatives [62].


#### **Table 2.**

*A review of some of the UK's waste management regulations [66].*

*Evaluating Waste-to-Energy Technologies as a Waste Management Solution for Uganda DOI: http://dx.doi.org/10.5772/intechopen.101904*
