Date palm trees produce huge amount of agricultural wastes in the form of dry leaves, stems, pits, seeds etc. A typical date tree can generate as much as 20 kilograms of dry leaves per annum while date pits account for almost 10 percent of date fruits.
Date palm biomass is found in large quantities across the Middle East
Date palm is considered a renewable natural resource because it can be replaced in a relatively short period of time. It takes 4 to 8 years for date palms to bear fruit after planting, and 7 to 10 years to produce viable yields for commercial harvest. Usually date palm wastes are burned in farms or disposed in landfills which cause environmental pollution in dates-producing nations.
The major constituents of date palm biomass are cellulose, hemicelluloses and lignin. In addition, date palm has high volatile solids content and low moisture content. These factors make date palm residues an excellent biomass resource in date-palm producing nations.
Date palm biomass is an excellent resource for charcoal production in Middle East
A wide range of physico-chemical, thermal and biochemical technologies exists for sustainable utilization of date palm biomass. Apart from charcoal production and energy conversion (using technologies like combustion and gasification), below are few ways for utilization of date palm wastes:
Conversion into fuel pellets or briquettes
Biomass pellets are a popular type of alternative fuel (analogous to coal), generally made from wood wastes and agricultural biomass. The biomass pelletization process consists of multiple steps including pre-treatment, pelletization and post-treatment of biomass wastes. Biomass pellets can be used as a coal replacement in power plant, industries and other application.
Conversion into energy-rich products
Biomass pyrolysis is the thermal decomposition of date palm biomass occurring in the absence of oxygen. The products of biomass pyrolysis include biochar, bio-oil and gases including methane, hydrogen, carbon monoxide, and carbon dioxide.
Depending on the thermal environment and the final temperature, pyrolysis will yield mainly biochar at low temperatures, less than 450 0C, when the heating rate is quite slow, and mainly gases at high temperatures, greater than 800 0C, with rapid heating rates. At an intermediate temperature and under relatively high heating rates, the main product is bio-oil.
Bio-oil can be upgraded to either a special engine fuel or through gasification processes to a syngas which can then be processed into biofuels. Bio-oil is particularly attractive for co-firing because it can be more readily handled and burned than solid fuel and is cheaper to transport and store.
Conversion into biofertilizer
Composting is the most popular method for biological decomposition of organic wastes. Date palm waste has around 80% organic content which makes it very well-suited for the composting process. Commercial-scale composting of date palm wastes can be carried out by using the traditional windrow method or a more advanced method like vermicomposting.
Waste management is a serious problem in Nigeria, and Delta State is no exception. It is a problem that starts at a cultural level: many of the populace believe that once they remove waste from their homes it is no longer their concern. It is a problem that starts at a cultural level: many of the populace believe that once they remove waste from their homes it is no longer their concern, and you often see people disposing of their household waste in the streets at night. Once the waste gets out into the streets, it’s perceived as the duty of the government to handle it.
However, I have never yet heard of any Nigerian politician making waste management a feature of his or her manifesto during the election campaign process. Having said that, a few of Nigeria’s political leaders deserve to be commended for coming to terms with the fact that waste has to be managed properly, even if such issues were far from their minds when they entered political office.
Legislation and Framework
Nigeria does have a waste legislation framework in place. Its focus has been on the most toxic and hazardous waste: partly in response to some major pollution incidents in the 1980s, the government took powers in relation to Hazardous Waste in 1988. In the same year, the Federal Environmental Protection Agency was established – and was subsequently strengthened by the addition of an inspectorate and enforcement department arm in 1991, with divisions for standard regulation, chemical tracking and compliance monitoring. These laws have since given rise to regulations and guidelines pertaining to environmental and waste management issues.
Under our laws, waste management in each state is the duty of the local governments that fall within it, but few are taking an active approach to implementing and enforcing the sensible measures that the regulations require. A small number of states have taken over this task from local government, and Delta State’s decision to do this has led to significant new investment in waste management.
One of the fruits of that investment is the Delta State Integrated Waste Management Facility at Asaba for treating both household and clinical waste generated locally. It was developed when the Delta State government decided to put an end to the non-sustainable dumping of waste in Asaba, the state capital.
Integrated Waste Management Facility at Asaba
It is described as an integrated waste management facility because it includes a composting department, a recycling department and a (non-WTE) incineration department. Trucks carrying waste are weighed in as they come into the facility. From the weigh bridge, they move to the relevant reception bay – there are separate ones for household and clinical wastes – to tip their load, and are then weighed again on the way out.
Medical waste is taken directly for incineration, but household wastes are sent along conveyors for sorting. Recyclables and compostable materials are, so far as possible, separated both from other waste and from one another. Each recyclable stream ends up in a chamber where it can be prepared for sale. The compostable materials are moved to the composting section, which uses aerated static pile composting.
The remaining waste is conveyed into the three incinerators – moving grate, rotary kiln and fixed end– for combustion. The resulting ash is recycled by mixing it with cement and sharp sand and moulding it into interlocking tiles. The stacks of the three incinerators are fitted with smoke cleaning systems to reduce emissions. The process produces wastewater, which is channelled to a pit where it is treated and reused. Overall, 30% of the waste is composted, 15% recycled and 55% incinerated.
There are many examples of sophisticated waste infrastructure being built in developing countries, but failing because the necessary collection systems were not in place to support them. To ensure that this problem is avoided at Asaba, the Delta State government is working with a group known as the Private Sector Participants (PSP).
Each member of this group has trucks assigned to them and has been directed to collect household waste from different parts of the city, for delivery to the facility for treatment. The arrangements made by each PSP are different: some collect from outside individual properties, and some from communal sites; most collect waste that is found in the streets; and while each is subsidised by the state, households also have to pay towards the cost.
Before the Asaba facility was developed, most of the wastes generated in Asaba were disposed of at a dumpsite just adjacent to the Delta State Airport. This created a pungent odour, as well as visual disamenity for people nearby. A great deal of remediation work is now taking place at the dumpsite, which is vastly improving the local environmental quality.
War on Waste
Of course, although this is an improvement there remains more to do. First on the list is education. People do not know how sustainable waste management can impact positively in their lives, reducing their exposure to toxins as well as improving their surroundings. Nor do they understand that recycling a beverage can or a plastic bottle will cost less than producing one from virgin materials and will have a lesser environmental impact. There remains a good deal of cultural change and environmental education that is needed before people will stop throwing waste and litter on the streets – but there are few countries where, to some extent, the same would not be true.
Next is the lack of infrastructure. Nigeria has 36 states and a federal capital, yet the facility in Asaba is the first publicly commissioned one of its kind in the country; there are also some privately owned incinerators that a few companies in Port Harcourt use to treat wastes from vessels (ships), hospitals and industries. Lagos state and Abuja are relatively advanced, simply by virtue of having put in place a few managed landfills, but they are still far from having the level of facility that Asaba can now boast.
The backbone of Asaba’s progress is the state government’s commitment to put a proper waste management solution in place. We’ve seen the impact in the form of infrastructure, collections and remediation, and law enforcement work is starting to change people’s perception about waste management in Delta State. At the moment, plans are being concluded to setup another facility in Warri, Delta State’s industrial hub, which will be twice the size of the Asaba facility.?
My hope is that the progress made by Delta State will be a beacon for other states’ governments. The example we are providing of cleaner, hygienic, more environmentally responsible waste management, and the positive changes that is bringing about, should inspire new development elsewhere in the country, which could equal or even exceed Delta State’s results. So whilst Nigeria’s track record on waste may leave a lot to be desired, the path ahead could be a great deal more promising.
Note: The article is being republished with the kind permission of our collaborative partner Isonomia. The original article can be found at this link.
The primary aim of sustainable solid waste management is to address concerns related to public health, environmental pollution, land use, resource management and socio-economic impacts associated with improper disposal of waste. “This growing mountain of garbage and trash represents not only an attitude of indifference toward valuable natural resources, but also a serious economic and public health problem”. These words from the former US President Jimmy Carter is enough to understand the social, economical and environmental impact of mismanaged waste disposal and an urgent call for help to look for innovative, smart, sustainable and effective waste disposal techniques.
According to UNEP, around 3 billion tons of waste is generated every year, with industrial waste being the largest contributor, especially from China, EU and USA. There has been a steady increase in the quantity of e-wastes and hazardous waste materials. The UNEP study observed a drastic shift from high organic to higher plastic and paper corresponding to increase in the standards of living and also made an interesting correlation between the higher GDP and the quantity of municipal waste collections.
In developing and under-developed countries, the use of open dumps to dispose of the solid waste from different sectors is staggeringly high compared to the developed and high income countries that are more dependent on recycling and use of sanitary landfills that are isolated from the surrounding environment until it is safe.
There are serious concerns on the increasing cost of waste disposal, especially in developing countries. It is estimated that around $200 billion are being spent on waste management in the OECD countries for both municipal and industrial waste.
For developing countries, at least 20-50% of its annual budget is devoted to waste management schemes and strategy that has been reported insufficient and inefficient at the same time. In these countries, use of unscientific and at times unethical and outdated waste management practices have led to various environmental repercussions and economic backlashes. Even the relatively small proportion of waste recycling and other waste minimization and re-use techniques for waste disposal is alarming.
The increasing cost of waste disposal is a cause of major concern in developing nations
As sustainable solid waste management evolves through waste awareness among general public, efforts within the industry, and waste management becoming not just an environmental concern but a political and strategic apprehension too, there are realistic chances of advancements and scientific innovations.
Innovation will then give birth to revolutionary and self-sustaining ideas within the industry, which earlier focused on basic waste management, will now grow towards maximum utilization and sustainable management of waste.
In the last couple of decades, sustainable solid waste management has become a matter of political significance with robust policies, strategies and agendas devised to address the issue. The good thing is that the industry has responded with innovative, cost-effective and customized solutions to manage solid wastes in an environmental-friendly manner.
When it comes to waste minimisation and moving material up the waste hierarchy you will find partisan advocates for the roles of the public, private and community sectors. Each will tell you the reasons why their sector’s approach is the best. The private sector will extol their virtues as the only ones capable of efficiently and effectively doing the job. They rightly note that they are the providers on the front lines who actually recover the vast majority of material, that the private sector approach drives innovation and efficiency, and that if waste minimisation is to be sustainable this must include economic sustainability.
The community sector on the other hand will make a strong case to say that their model, because it commonly encompasses social, environmental, and economic outcomes, is able to leverage value from recovered materials to dig deeper into the waste stream, to optimise recovered material quality, and to maximise employment and local economic benefit.
Before recycling and composting were economically viable prospects, community sector organisations led the way, developing many of the techniques now widely used. They remain the leaders in marginal areas such as furniture reuse, running projects that deliver environmental outcomes while providing wider community benefits such as rehabilitation and training for marginalised groups.
Finally, in the public sector corner, advocates will point out that the profit-driven private sector will only ever recover those materials that are able to generate positive revenues, and so cannot maximise waste minimisation, while social outcomes are strictly a secondary consideration. The community sector, on the other hand, while encompassing non-monetary values and capable of effective action on a local scale, is not set up to deliver these benefits on a larger scale and can sometimes struggle to deliver consistent, professional levels of service.
The public sector can point to government’s role in legislating to promote consistent environmental and social outcomes, while councils are major providers and commissioners of recycling services and instrumental in shaping public perceptions around waste issues. The public sector often leads in directing activity towards non-monetary but otherwise valuable outcomes, and provides the framework and funding for equity of service levels.
So who is right? Each sector has good arguments in its favour, and each has its weaknesses. Does one approach carry the day? Should we just mix and match according to our personal taste or based on what is convenient?
Perhaps we are asking the wrong question. Maybe the issue is not “which approach is better?” but instead “how might the different models help us get to where we ultimately want to go?”
Smells Like Waste Minimisation
So where do we want to go? What is the waste minimisation end game?
If we think about things from a zero waste perspective, the ideal is that we should move from linear processes of extraction, processing, consumption and disposal, to cyclical processes that mimic nature and that re-integrate materials into economic and natural systems. This is the nirvana – where nothing is ‘thrown away’ because everything has a further beneficial use. In other words what we have is not waste but resources. Or to put it another way – everything has value.
Assuming that we continue to operate in an essentially capitalist system, value has to be translated into economic terms. Imagine if every single thing that we now discard was worth enough money to motivate its recovery. We would throw nothing away: why would we if there was money to be made from it?
So in a zero waste nirvana the private sector and the community sector would take care of recovery almost automatically. There might evolve a community and private sector mix, with each occupying different niches depending on desired local outcomes. There would be no need for the public sector to intervene to promote waste minimisation. All it would need to do would be to set some ground rules and monitor the industry to ensure a level playing field and appropriate health and safety.
Returning to reality, we are a long way from that zero waste nirvana. As things stand, a bunch of materials do have economic value, and are widely recycled. Another layer of materials have marginal value, and the remainder have no value in practical terms (or even a negative value in the case of hazardous wastes).
The suggested shift in perspective is most obvious in terms of how we think about the role of the public sector. To bring us closer to our goal, the public sector needs to intervene in the market to support those materials of marginal value so that they join the group that has genuine value.
Kerbside (or curbside) collection of certain materials, such as glass and lower value plastics, is an example of an activity that is in effect subsidised by public money. These subsidies enable the private sector to achieve environmental outcomes that we deem sufficiently worthwhile to fund.
However, the public sector should not just be plugging a gap in the market (as it largely does now), but be working towards largely doing itself out of a job. If we are to progress towards a cyclical economy, the role of the public sector should not be to subsidise marginal materials in perpetuity, but to progressively move them from marginal to genuinely economic, so that they no longer require support.
At the same time new materials would be progressively targeted and brought through so that the range and quantity requiring disposal constantly shrinks. This suggests a vital role for the public sector that encompasses research, funding for development of new technologies and processes, and setting appropriate policy and price structures (such as through taxes, levies, or product stewardship programmes).
Similarly, the community sector, because it is able to ‘dig deeper’ into the waste stream, has a unique and ongoing role to play in terms of being able to more effectively address those materials of marginal value as they begin to move up the hierarchy. The community sector’s unique value is its ability to work at the frontiers.
Meanwhile, the private sector’s resources and creativity will be needed to enable efficient systems to be developed to manage collection, processing and recycling of materials that reach the threshold of economic viability – and to create new, more sustainable products that fit more readily into a waste minimising world.
In the end, then, perhaps the answer is to stop seeing the three models as being in competition. Instead, we should consciously be utilising the unique characteristics of each so that we can evolve our practices towards a future that is more functional and capable of delivering the circular economy that must eventuate if we are to sustain ourselves on this planet.
Note: The article is being republished with the kind permission of our collaborative partner Isonomia. The original article can be viewed at this link
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