Pakistan is the sixth most populous country in the world with a population of 216.5M and annual growth rate of 2%. It is an agrarian country with two thirds of its population living in rural areas. Despite its abundant renewable energy sources, Pakistan is facing severe energy crises where it imports a third of its energy requirements and is still using conventional methods of energy generation that produce significant CO2 emissions.
Majority of the rural population in Pakistan meet their cooking and heating needs by burning biomass like animal dung, wood fuel and charcoal in traditional cook stoves which are inefficient and causes household indoor air pollution (HAP). About 28,000 people die each year due to HAP, and it accounts for 40 million cases of acute respiratory illnesses per annum causing significant economic burden which costs about 1% of GDP per annum. Also, Pakistan is facing severe deforestation problem and currently forests cover only 2.5% of the land area as every year 27000 hectare is lost due to deforestation leading to increased CO2 accumulation in the atmosphere.
There are huge amounts of waste in Pakistan including 20MT/yr solid waste of which almost half is biomass like (food waste, paper leaves, grass and fodders), 70MT/year of agriwaste like wheat and rice husks, cotton sticks and sugar-cane residues, and 365MT/Yr of animal waste coming from more than 170M heads of cows, buffalos, cattle, sheep, camels and goats. Exploiting this agricultural and animal waste, this project aims to investigate the feasibility of a novel Waste to Energy system to produce biogas which will be further upgraded and separated into biomethane and carbon dioxide.
The biogas (before upgrading) will be piped to households close to the anaerobic digestion plant and investigated for cooking and the effects of using it on the indoor air quality will be assessed compared to using wood for cooking.
Then the upgraded biogas to biomethane will be used for cooking and heating while CO2 will be used for wide range of industrial applications. Also, the proposed system will produce nitrogen enriched bio-fertilisers that can be used for soil enhancement, increased land fertility and food production.
The widespread of the proposed technology will have major impacts on Pakistan population where clean, affordable and secure source of energy can be generated using locally available waste. Based on the waste produced from the 70M heads of cows and Buffalos only, over 57488Mm³/yr of biogas and 30MT/yr of nitrogen enriched bio-fertilisers can be produced. This will significantly reduce Pakistan fuel imports, enhance the living standards of the rural communities particularly women, girls and disadvantaged groups, reduce CO2 emissions and improve the environment.
The hydrogen economy is seen as one of the curcial ways to decarbonise transport and domestic and industrial
heat. However, bulk hydrogen will be needed to fuel the hydrogen economy so a means of producing hydrogen
with zero emissions is needed if there is to be any environmental benefit. This project is looking at the feasibiliy
of producing bulk hydrogen from natural gas which is converted to hydrogen and CO2 using a Steam Methane
Reformer, then using Cambridge Carbon Capture Ltd's Patented CO2LOC CO2 capture and mineralisation
technology to strip out the CO2 and convert it to a commercially useful mineral by-product. The commercial
focus of the project is to produce a zero emissions H2 refuelling station for fuel cell vehicles thereby providing
vital refuelling infrastructure removing a significant barrier to the uptake of these types of vehicles.
The development and upscaling of renewable hydrogen sources are a prerequisite if the UK is to effectively
help solve the energy ‘trilemma’ of reducing emissions from electricity generation, improving security of
supply and reducing costs. Hydrogen is seen as an alternative clean energy source to replace polluting
traditional fuels however, 95 % of the world's hydrogen is derived from non-renewable fuels. Alternative
renewable sources of hydrogen are required. This feasibility project brings academia and industry together to
develop a combined biological / electrochemical process to convert animal and human waste to renewable
hydrogen. It will focus on removing technical barriers which are limiting scale up and commercialisation.
Success will lead to significant electricity generation from abundant, low value, potentially polluting waste
streams and the development of the process will open the way for the technology to be exploited in other
overseas markets and other industry sectors such as food manufacturing and processing.
Awaiting Public Project Summary
The summary of overall project findings is as follows.
• The concentrations of ammonia, urea, organic nitrogen and free available nitrogen in farm slurries and industrial fertilisers vary depending on the nature of the material in terms of its source, application and chemical composition. Pig slurry has different composition and characteristics to Cattle slurry. Pig slurries contain predominantly Ammonium Nitrogen, typically 70% and 30% Organic Nitrogen. Whereas Cattle slurry typically contains 60% Organic Nitrogen and 40% Ammonium Nitrogen. The age of the cattle slurry also has an impact on the nitrogen type available in the slurry with ageing resulting in a conversion of organic nitrogen to ammoniacal nitrogen. Total nitrogen contents in samples analysed during the laboratory and demonstrator trials on Harper Adams farm ranged from 650mg/l and up to 7000mg/l. However, once a solids settlement period was incorporated during sample trials the total nitrogen levels stabilised to within 2000 and 3000mg/l. Ammoniacal nitrogen levels varied as a proportion of the total nitrogen content of the slurry samples ranging from 8% and up to 75% of the nitrogen content.
• The restrictions on ammonia pollution in agriculture vary from region to region, but all are becoming more stringent. In the UK nitrogen fertiliser regulations typically discriminates according to nitrogen availability, materials with high levels of available nitrogen such as poultry manure, pig slurry, cattle slurry and broiler manure are in some cases subject to application timing restrictions and additionally to rules which dictate application methods. The imposition of regulations such as IPPC and Nitrate Vulnerable Zones (NVZ) in the UK have in recent years improved the utilisation efficiency of organic fertilisers; this has resulted in the reduced use of inorganic nitrogen sources, i.e. mineral fertilisers. In Denmark where similar regulation was imposed nitrogen fertiliser use has declined by 50% since 1990. The UN/ECE Gothenburg Protocol and the EU National Emissions Ceiling Directive have been implemented to control ammonia emissions (amongst other pollutants) at the national level. Both the Protocol and the Directive have national emission ceilings for 2010, and both are currently undergoing revision to include revised more stringent ceilings for 2020.
• Laboratory and demonstrator trials successfully proved the feasibility of utilising enzymatic treatment to enhance the conversion of organic nitrogen to ammoniacal nitrogen as a precursor to controlled volatilisation and absorption. Ammoniacal nitrogen contents within the slurry matrix were improved by up to 50%. Thus offering higher potential yields in subsequent stages of the process the air assisted volatilisation, absorption and neutralisation of ammonia into a liquid ammonium form.
• The DGC physical stripping and ammonia absorption method was proven to convert upto 85% of the ammonia in the slurry matrix into a liquid ammonium solution during early trials.
• Further efficiency improvements and increased yields may be possible. High solids in the slurry and foaming was a real issue during laboratory and demonstrator trials which impacted greatly on the process performance. Better control of solids content and redesigning vessels and piping design for foaming control would improve fluid flows and increase aeration rates essential to the stripping/volatilisation process performance.
• The CO¬2(eq) emissions associated with using (i) dairy slurry topped up with mineral fertiliser, (ii) mineral fertiliser alone, and (iii) ammonium nitrate recovered from dairy slurry as fertiliser on a crop of Winter Wheat grown on a medium soil with a soil nitrogen index (SNS) of 1 are presented in Section 2. The final emissions of the recovered Ammonium Nitrate from the AMM2FERT process are 3.26 tonnes CO2(eq)/ hectare which are lower than the emissions produced by using the standard farming practise of using slurry and topped up with mineral ammonium nitrate, but higher than those of mineral ammonium nitrate fertilisers alone. However, as described previously 98 % of the embodied emissions associated with recovered ammonium nitrate from AMM2FERT are due to the use of electricity in the system. Thus, a small reduction of the energy used in the process could reduce the total emissions dramatically. Further process optimisation work and incorporation of renewable energy supplies can potentially reduce the AMM2FERT process carbon footprint significantly.
• Several new applications have been identified for the AMM2FERT process including i) direct conversion of ammonia from pig and cattle slurry to concentrated liquid ammonium-N fertiliser; ii) post-anaerobic digestion conversion of readily available ammonium-N to liquid ammonium-N fertiliser and iii) the enhanced growth of Urease enzyme producing microorganisms for nutrient growth and stabilisation. These applications present real market potential for future exploitation of the AMM2FERT process.