Background Statement

1. Introduction

2. Physical and Chemical Properties of Human and Livestock Urine and Feces

Table 2. Composition and nutrient content of animal manure and human excreta [20,21,22]

Table 3. Proximate and ultimate analysis of human and livestock wastes expressed on a dry basis.

3. Thermochemical Conversion of Human and Animal Waste

3.2. Gasification

Gasification is another thermochemical conversion pathway that can convert human and animal waste into solid, liquid, and gaseous products (syngas). Gasification is often referred to as a biomass-to-gas conversion process because its target is hydrogen-rich gas comprising mostly H₂ and CO. Substantial quantities of hydrocarbons, such as CH₄ as well as CO₂ and H₂O, and often N₂, are also present in the gaseous product from gasification [8]. Synthetic gas (syngas) is defined as a gas with H₂ and CO as the main components and is a product of gasification. Syngas has myriad applications as a precursor for the production of higher alcohols, green fuels and chemicals via syngas fermentation of Fischer-Tropsch (FT) synthesis [39].

Gasification can be grouped as conventional or hydrothermal gasification based on the temperature, pressure, and gasifying agents. It should be mentioned that both gasification processes have identical products, but their composition and yield are often different. Figure 5 outlines the differences between conventional and hydrothermal gasification processes.

Studies on the gasification of human and animal waste are related to the parametric evaluation of the impact of process conditions on gaseous yield, process optimization [64], energy and exergy analysis [65], kinetics studies [66], and techno-economic and life cycle assessment [67,68]. Some researchers have also focused on developing innovative heterogeneous catalysts for improving product yield and selectivity or co-gasification with other waste materials [69].

Liu et al. [69] studied the synergistic effect of a gasifying mixture of petroleum coke and chicken manure. They reported that chicken manure addition during the gasification of petroleum coke helped increase the hydrogen content in the produced syngas. The authors also explored the catalytic effect of chicken manure ash on gasification efficiency. Chicken manure ash increased the gasification efficiency by five times. They suggested that this must have been due to the ash’s high potassium and calcium content. Onabanjo et al. [70] explored the possibility of producing hydrogen from human feces through conventional gasification. Aspen Plus thermodynamic equilibrium modelling was used to estimate the quantity of energy that could be produced from human feces. They reported that a 3-6 wt.% ash content in fresh human feces makes it a viable raw material for gasification. The product gas obtained from human feces at an optimal equivalence ratio (ER) of 0.31 was characterized by 24 MJ/kg and 17 MJ/kg lower heating and exergy values, respectively [70].

Hussein et al. [71] studied the effects of gasifying agents (air, steam, carbon dioxide, and nitrogen) and temperatures ranging from 600 to 1000 ^oC on the pyrolysis and gasification of chicken manure. It was reported that a higher temperature will produce a higher syngas yield. Regarding the gasifying media, in terms of increasing order, the air medium produced the lowest yield, followed by nitrogen, steam, and carbon dioxide. They revealed that the reaction time is inversely proportional to the energy yield. The feasibility of a two-step gasification route for producing hydrogen gas from cattle manure was examined by studying the temperature impact on not only biochar characteristics but also product distribution. The biochar from the joint pyrolysis-carbonization was found to have a low volatile percentage composition and high carbon composition at 500 ^oC. This result suggests that hydrogen can be produced from the two-step gasification process [72].

Hydrothermal gasification is a suitable valorization pathway for animal manure due to the high moisture content of the materials. Nanda et al. [73] explored the feasibility of hydrogen production from horse manure via alkali catalyst-enhanced hydrothermal gasification. The impact of temperature (400–600 °C), two biomass-to-water ratios (BTW) of 1:5 and 1:10 and reaction time (15–45 min) at a pressure range of 23–25 MPa on hydrogen yield was comprehensively explored. The maximum hydrogen yield was obtained at a high temperature of 600 °C and a 1:10 biomass-to-water ratio for 45 min with a 2 wt.% Na₂CO₃ catalyst. Another study showed that cattle manure could be used as a promising feedstock for hydrothermal gasification with Ni heterogeneous catalysts supported by hydrochar prepared from cattle feed [74]. Liu et al. [75] proposed a mechanism for the transformation of nitrogenous compounds during the hydrothermal gasification of chicken manure (Figure 6). Two main mechanisms were inherent: ionic and free radical degradation, with both mechanisms dependent on temperature. The ionic mechanism occurs at low temperature subcritical or near critical conditions while the free radical degradation is inherent at high temperatures > 400 ^oC. Some intermediate products, such as amino acids, are also produced via the Maillard reaction. Three main reactions are involved in free radical degradation: steam reforming, pyrolysis and Maillard reaction. An elevation in temperature led to the migration of nitrogenous compounds in the raw materials to the aqueous liquid while the Maillard reaction conditions are created by the hydrolysis of proteins and amino acids in the initial phases. As the temperature increases beyond 400 ^oC, some nitrogen-containing compounds are converted into condensable gases via stream reforming and pyrolysis (Figure 5).

A summary of studies related to heterogeneous catalyzed gasification of human and animal waste, kinetics studies and process integration studies are presented in Table 5. Detailed information on the gasification of different biogenic waste can also be found elsewhere [8,76].

Figure 6. An overview of the reaction mechanism for nitrogen recovery during the hydrothermal gasification of chicken manure. Adapted from Liu et al. [77].

Figure 6. An overview of the reaction mechanism for nitrogen recovery during the hydrothermal gasification of chicken manure. Adapted from Liu et al. [77].

Hydrothermal gasification is still a challenging technology due to the high temperature and pressure requirement. The mechanism of hydrothermal gasification of human and animal waste is still unclear. Although some researchers have documented the reaction mechanism of liquid feedstock decomposition such as glycerol in supercritical water [78]. Problems such as corrosion issues, reactor material durability, waste heat utilization, safety and risk associated with extreme reaction conditions. Catalysts are often used to reduce the reaction temperature during hydrothermal gasification. However, the harsh environment facilitates the decline in the surface area of metallic catalysts and some structural changes causing significant deactivation, a phenomenon known as catalyst sintering [8].

Table 5. Summary of past studies on the gasification of human and livestock wastes.

Table 5. Summary of past studies on the gasification of human and livestock wastes.

Type of gasification and key products	Key findings	References
Gasification type: Conventional fluidized bed gasification. Feedstock: Poultry litter Study focus: Parametric studies and process optimization. To investigate the effect of adding limestone (CaCO3), different gasifying agent and temperature on product gas yield and cold gas efficiency during gasification.	Highest temperature of 800 oC resulted in a product gas with a lower heating value of 4.5MJ/Nm3 and cold gas of 89% efficiency. Gas composition at optimum process conditions include: H2: 10.78%, CO: 9.38%, CH4: 2.61, and CO2: 13.13 Owing to the high quantity of potassium and phosphorus in poultry ash, the limestone drastically reduced the bed’s agglomeration.	Pandey et al. [79]
Gasification type: Conventional gasification Feedstock: Chicken manure Study focus: Co-gasification and catalytic studies. Study the synergistic effect of gasifying petroleum coke and chicken manure while the chicken manure is a catalyst.	Chicken manure is a promising precursor for hydrogen production via co—gasification with pet coke in the presence of chicken manure-derived ash as a catalyst. The high potassium and calcium content in chicken manure ash made it efficient as a catalyst as it yielded fivefold of CO than what the petroleum coke alone would have yielded. ∙	Liu et al. [69]
Gasification type: Conventional gasification Feedstock: Human faces Study focus: Thermodynamic and energy analysis with Aspen plus simulation. Explored the viability of human feces as a raw material for gasification. Estimation of the quantity of energy that could be produced from human feces.	They reported that human feces comprises 3-6 wt. % ash and 70-82 wt. % moisture making it a suitable precursor for gasification. The product gas from human feces is optimum at equivalence ratio of 0.31 and is characterized by 24 MJ/kg and 17 MJ/kg lower heating and exergy values, respectively.	Onabanjo et al. [70]
Gasification type: Conventional gasification Feedstock: Chicken manure Study focus: Parametric studies The effect of gasifying media (air, steam, carbon dioxide, and nitrogen) and temperatures ranging from 600 oC to 1000 oC on the pyrolysis and gasification of chicken manure.	Higher temperatures favor improved product gas yield. It was revealed that reaction time is inversely proportional to the energy yield. Air gasification is the most preferred among all other gasifying agents.	Hussein et al. [71]
Gasification type: Conventional gasification Feedstock: Cattle manure Study focus: Parametric studies The viability of a two-step gasification route for producing hydrogen gas was examined by studying the temperature impact on biochar characteristics and product distribution.	Approximately 1.61 m3/kg of syngas, 0.93 m3/kg of hydrogen and 57.58% of hydrogen concentration was obtained at an optimum temperature of 850 oC. The biochar produced from the two-step gasification process has a low volatile percentage composition and high carbon content.	Xin et al. [80]
Gasification type: Hydrothermal gasification Feedstock: Horse manure Catalyst: Homogeneous alkali catalyst including NaOH, Na2CO3 and K2CO3. Study focus: Parametric studies Explored the effect of reaction temperature (400–600 °C), biomass-to-water ratio (1:5 and 1:10) and reaction time (15–45 min) at a pressure range of 23–25 MPa on product yield during horse manure gasification in supercritical water.	Higher temperature favored hydrogen yield and selectivity. Na2CO3 performed better than other homogeneous catalyst in improving hydrogen yield. At optimum conditions (600 °C and 1:10 biomass-to-water ratio for 45 min), a maximum hydrogen yield of 5.31 mmol/g was reported.	Nanda et al. [81]
Gasification type: Conventional gasification Feedstock:Pig manure compost Heterogeneous catalyst: Ni/Al2O3, Ni-loaded brown coal char. Study focus: Catalytic effect of supported Ni catalyst during gasification and parametric studies.	Ni-loaded brown coal char is a promising gasification catalyst even at lower temperatures. The catalysts developed promising resistance to coke formation compared to the commercial Ni/Al2O3. Temperature and steam/biomass–carbon ratio is an important consideration in improving gas yield.	Xiao et al. [82]
Gasification type: Hydrothermal gasification Feedstock: Chicken manure Catalyst: K2CO3 Study focus: Parametric studies, kinetics, and reaction mechanism evaluation.	Complete gasification efficiency was attained with the use of 10 wt.%, and K2CO3 at 700 oC. The migration pathways of nitrogenous intermediates show that the Maillard reaction plays a significant role. Two reaction mechanisms for the removal of nitrogen in chicken manure gasification are ionic and free radical degradation.	Liu et al. [77]

3.3. Liquefaction

Liquefaction is a biomass-to-liquid (BTL) conversion pathway similar to pyrolysis but different in terms of operating temperature (200–450 ^oC), pressure (5–25 MPa) and the presence of a solvent, usually water or alcohols. It is mostly used for the conversion of wet biomass (wastes) into crude oil, also referred to as biocrude oil [83]. The yield and quality of biocrude oil are dependent on the raw material composition, residence time, catalyst, temperature, pressure, and solvent [84].

Hydrothermal liquefaction (HTL) is different from other hydrothermal processes such as supercritical water gasification and hydrothermal carbonization (HTC) in terms of the desired products and operating conditions. Figure 7 describes different phase diagrams for hydrothermal processes as well as the operating conditions ranges. Hydrothermal gasification is favorable at high-temperature supercritical conditions (> 400 ^oC) and the desired product is high-quality syngas [85]. In contrast, HTC is focused on the formation of solid fuels with improved physicochemical properties for subsequent energy and environmental applications.

The biocrude oil obtained from liquefaction has a lower oxygen content, is more viscous and has an elevated HHV compared to pyrolysis oils [86]. Hydrothermal liquefaction (HTL) offers the advantages of feedstock flexibility and does not require precursor drying. Studies on the liquefaction of human waste focus on developing pathways for nitrogen transformation [87], process optimization or the development of novel heterogeneous catalysts for improving oil yield and quality [11]. Lu et al. [11] investigated the effects of temperature (260 °C, 300 °C, 340 °C), retention time (10 min, 30 min, 50 min) and total solid content (5%, 15%, 25%) on biocrude yield and nutrient recovery during the HTL of human feces. They revealed that approximately half of the carbon content in human feces was converted to biocrude oil, while 72% of nitrogen was found in the aqueous phase. They also reported that human feces contained metals such as calcium, aluminum, magnesium, zinc, iron, sodium, and potassium. The results showed that human feces are a potential source of energy and nutrient recovery. The authors proposed possible reaction pathways for the conversion of human feces via HTL (Figure 8).

Figure 7. Hydrothermal processing condition in water phase diagram. Adapted from [88]

Figure 7. Hydrothermal processing condition in water phase diagram. Adapted from [88]

The pathways in Figure 8 include intermediate reactions such as (a) hydrolysis; (b) dehydration; (c) decarboxylation; (d) deamination; (e) Maillard reaction; (f) cyclization; (g) polymerization; and (h) decomposition [11]. The hydrocarbons found in the biocrude oil during HTL were produced through the decarboxylation of the fatty acids. It should be mentioned that the fatty acids are from the hydrolysis of lipids in human waste. The ketones and aldehyde functional groups were produced from polysaccharides through a series of intermediate reactions including hydrolysis, dehydration and decomposition reactions [11]. In contrast, nitrogenous compounds such as pyridine, pyrrolidine indole and quinolone are derived from monosaccharides and amino acids through the cyclization and Maillard reactions.

Conti et al. [89] explored the possibility of recovering nutrients and energy production from the biodegradation of animal manure, sewage sludge, and fish sludge with or without K₂CO₃ (catalyst) under subcritical (350 ^oC) and supercritical conditions (450 ^oC). They reported that all the wastes gave a high yield of biocrude, with fish sludge and sewage sludge giving yields of 50% and 45%, respectively. Moreover, animal manure was able to produce a quality biocrude in the presence of the catalyst and under supercritical conditions. Inorganics such as calcium, phosphorus, and magnesium were obtained from the solid phase, as approximately 55-80% and 50-60% of carbon were recovered from fish and swine sludge, respectively [90].

Li et al. [91] compared the HTL of dairy manure, broiler manure, laying hen manure, swine manure, and beef manure. They revealed that swine manure had the highest biocrude oil yield (30.85%) at 340 ^oC while the other manure yields ranged from 15% to 25%. The heavy metals from these manures (copper, zinc, lead, cadmium) are heavily distributed in the solid residue after hydrothermal liquefaction. The influence of temperature, solvent filling rate, and solid-liquid rate on the constituents, features, and yield of bio-oil derived from pig manure was examined by some researchers [92]. The highest yield of the bio-oil was found to be 35.56%, while its heating value ranged from 34.39 to 37.03 MJ/kg. The bio-oil was composed of ketones, nitrogen compounds, organic acids, long-chain hydrocarbons, ethanol, and esters. The yield of the bio-oils had an inverse relationship with the solid-liquid rates, while it increased and decreased with solvent filling rates and temperature respectively [92]. A summary of previous studies related to the liquefaction of human and animal waste is presented in Table 6.

3.4. Hydrothermal Carbonization

Hydrothermal carbonization (HTC) is a thermochemical process for the pre-treatment of high moisture content biomass to make it viable for energy production. HTC uses relatively low temperatures and is suitable for any kind of biomass feedstock (Wei et al., 2011). HTC can convert human and animal waste into solid hydrochar, which has better physicochemical characteristics than raw feedstocks [94], and also produce liquid products that contain organic and inorganic value-added chemicals. The HTC hydrochar exhibits lower O/C and H/C ratios compared to dry torrefaction and turns into more lignin or coal-type materials [95]. HTC hydrochar can be used in a wide range of processes such as soil amendment [96], CO₂ capture [97], nanoparticles (for making composites) (Liu et al., 2016), energy production [99], water purification [100] due to their unique physicochemical properties [101].

HTC could be adopted for the sustainable and environmentally benign treatment of human and animal waste for several environmental and energy applications. Some researchers have explored the conversion of human feces to hydrochar via HTC [102]. The effect of temperature (180, 210 and 240 °C) and reaction times (30, 60 and 120 min) during HTC of human excreta reveals that hydrochar yield decreased with elevating HTC temperature [102]. In addition, calorific value of the produced hydrochar rose from 24.7 to 27.6 MJ/kg with a rise in temperature. Afolabi et al. [103] showed that an hydrochar with improved HHV ranging from 19.79–25.01 MJ/kg was produced during the microwave HTC of raw human fecal sludges with increasing temperature ranges of 160–200 ^OC. Some researchers also assessed the energy efficiency during the HTC of human fecal wastes [104]. The energy balance results obtained during the HTC of fecal waste conducted at 200 °C and a reaction time of 30 min reveals that feces with 25% solids requires 63-65% of the overall reactor input energy for efficient heating. On the contrary, feces with lower solids (15% solid) would need lower energy (about 62-64 %) [104]. Another study showed that HTC could be used as an effective technology for the mitigation of SARS-CoV-2 in sewage sludge [105].

HTC can also be used to upgrade the properties of livestock manure for subsequent fuel applications. Jang et al. [106] reported that the HTC of livestock manure reduced the amount of C–O and C–H functional groups and elevated the number of aromatic C–H functional groups. Also, HTC increased the fixed carbon content, and energy density of livestock manure while the H/C and O/C ratios decreases. HTC could also be used aa nutrient recovery strategy from animal waste. Qaramaleki et al. [107] showed that cow manure is a promising source of phosphorus and nitrogen via HTC. However, the extent of phosphate extraction is dependent on the reaction temperature, acid addition, and acid concentration. Increasing HTC temperature and the addition of either citric acid or HCl led to an improved phosphate recovery in the aqueous phase. HTC could also be used for the valorization of anaerobic digestate to promote the circular economy and optimize material utilization [108].

Table 6. Summary of past studies on the gasification of human and livestock wastes.

Table 6. Summary of past studies on the gasification of human and livestock wastes.

Aim of study	Key findings	Authors
To examine the effects of temperature, holding time, and catalyst on the product distribution of a Ni-Tm/TiO2-catalyzed liquefaction of human feces.	They reported that the catalyst increases the product yield by 35% and gives energy recovery of 87%. A temperature of 330 oC and a holding time of 30 min gave the highest yield of biocrude (53.16%).	Wang et al. [109]
The feasibility of using hydrothermal liquefaction to produce energy (biocrude oil), recover nutrients and metals from human feces at specific retention times, temperatures, and total solid contents.	More than four-fifth of the waste was liquefied, which gives a yield of 34% and HHV of 40 MJ/kg. The results reported showed that human feces is a potential source of energy and nutrient recovery. Metals like calcium, aluminum, magnesium, zinc, iron, sodium, and potassium are key components of human feces.	Lu et al. [11]
Nutrient recovery and energy production from the decomposition of animal manure, sewage sludge, and fish sludge with or without K2CO3 (catalyst) under subcritical (350 oC) and supercritical conditions (450 oC).	The animal manure produced a quality biocrude in the presence of a catalyst and under supercritical conditions. All the wastes produced a high yield of biocrude, as fish sludge and sewage sludge produced a yield of 50% and 45%, respectively.	Conti et al. [90]
Studied the influence of temperatures, solvent filling rates, and solid-liquid rates on the composition and yield of bio-oil derived from pig manure are examined.	The highest bio-oil yield was found to be 35.56%, while its higher heating value ranges from 34.39 to 37.03 MJ/kg. The major bio-oil components include ketones, nitrogen compounds, organic acids, long-chain hydrocarbons, ethanol, and esters.	Wu et al. [92]
To compare the hydrothermal liquefaction of dairy manure, broiler manure, dairy manure, laying hen manure, swine manure, and beef manure.	The swine manure had the highest biocrude oil yield (30.85%) at 340 oC, while the other manure yield ranged from 15% to 25%. The solids recovered from these manures (copper, zinc, lead, cadmium) are heavily distributed in the solid residue from hydrothermal liquefaction.	Li et al. [110]
Explored the possibilities of converting camel manure into bio-oil and upgrading to drop—in fuel via hydrothermal liquefaction.	Optimum bio-oil yield of 37.9% was obtained during the liquefaction of camel manure. The bio-oil was upgraded to a drop-in fuel with similar properties to gasoline. The fuel has a minimum selling price of 0.87 U.S.$/kg. The produced gasoline led to a 7% reduction in emissions compared to the conventional gasoline production process.	Alherbawi et al. [111]
Studied the synergistic effect during the co-liquefaction of corn cob and cattle manure.	Co-liquefaction helped to improve the quality of bio-oil and yield compared to a single liquefaction of each feedstock. Developed a detailed reaction network mechanism for hydrothermal co-liquefaction of cattle manure and corn cob. Key intermediate products such as acids, amines, CO2, and 3 can influence the reaction environment pH value then affect the subsequent intermediate reactions.	He et al. [112]

4. Biological Conversion of Human and Animal Waste

5. Nutrient and Fertilizer Recovery from Human and Animal Waste

6. Bibliometric Research Trends on Resource Recovery from Human and Animal Waste

7. Conclusions and Future Research Directions

• Developing effective and safe methods for processing human and animal waste is needed. There is a need for safe and effective methods for processing hazardous waste to optimize nutrients and resource recovery.
• It is imperative to examine the most effective ways to use the recovered resources. Once resources have been recovered from human or animal waste, there is a need to determine the most effective ways to use them, such as for agricultural purposes or as a source of energy, while considering the environmental impacts of different utilization methods.
• Understanding the potential impacts of using recovered resources: It is important to understand any potential negative impacts of using recovered resources on the environment on a large scale. Usually, a cradle-to-grave lifecycle assessment should be performed.
• Developing technologies for the on-site recovery of resources: There is a need for technologies that can be used to recover resources from feces on-site, such as at a wastewater treatment plant or in a portable system. Offsite or district waste processing facilities with improved heat optimization and materials recovery could also be a viable alternative.

References

1. Krounbi, L.; Enders, A.; van Es, H.; Woolf, D.; van Herzen, B.; Lehmann, J. Biological and Thermochemical Conversion of Human Solid Waste to Soil Amendments. Waste Management 2019, 89, 366–378. [CrossRef]
2. WHO Population Practising Open Defecation (%).
3. Hunter, B.; Deshusses, M.A. Science of the Total Environment Resources Recovery from High-Strength Human Waste Anaerobic Digestate Using Simple Nitri Fi Cation and Denitri Fi Cation Fi Lters. 2019, 1–9. [CrossRef]
4. Hart, C.A.; Umar, L.W. Diarrhoeal Disease.
5. Hunter, B.; Deshusses, M.A. Science of the Total Environment Resources Recovery from High-Strength Human Waste Anaerobic Digestate Using Simple Nitri Fi Cation and Denitri Fi Cation Fi Lters. 2019, 1–9. [CrossRef]
6. Szogi, A.A.; Vanotti, M.B.; Ro, K.S. Methods for Treatment of Animal Manures to Reduce Nutrient Pollution Prior to Soil Application. 2015, 47–56. [CrossRef]
7. Orner, K.D.; Mihelcic, J.R. A Review of Sanitation Technologies to Achieve Multiple Sustainable Development Goals That Promote Resource Recovery. Environ Sci (Camb) 2018, 4, 16–32. [CrossRef]
8. Okolie, J.A.; Nanda, S.; Dalai, A.K.; Berruti, F.; Kozinski, J.A. A Review on Subcritical and Supercritical Water Gasification of Biogenic, Polymeric and Petroleum Wastes to Hydrogen-Rich Synthesis Gas. Renewable and Sustainable Energy Reviews 2020, 119, 109546. [CrossRef]
9. Okolie, J.A.; Epelle, E.I.; Tabat, M.E.; Orivri, U.; Amenaghawon, A.N.; Okoye, P.U.; Gunes, B. Waste Biomass Valorization for the Production of Biofuels and Value-Added Products: A Comprehensive Review of Thermochemical, Biological and Integrated Processes. Process Safety and Environmental Protection 2022, 159, 323–344. [CrossRef]
10. Lu, J.; Zhang, J.; Zhu, Z.; Zhang, Y.; Zhao, Y.; Li, R.; Watson, J.; Li, B.; Liu, Z. Simultaneous Production of Biocrude Oil and Recovery of Nutrients and Metals from Human Feces via Hydrothermal Liquefaction. Energy Convers Manag 2017, 134, 340–346. [CrossRef]
11. Lu, J.; Zhang, J.; Zhu, Z.; Zhang, Y.; Zhao, Y.; Li, R.; Watson, J.; Li, B.; Liu, Z. Simultaneous Production of Biocrude Oil and Recovery of Nutrients and Metals from Human Feces via Hydrothermal Liquefaction. Energy Convers Manag 2017, 134, 340–346. [CrossRef]
12. Min, K.J.; Park, K.Y. Economic Feasibility of Phosphorus Recovery through Struvite from Liquid Anaerobic Digestate of Animal Waste. Environmental Science and Pollution Research 2021, 28, 40703–40714. [CrossRef]
13. Onwosi, C.O.; Igbokwe, V.C.; Ezugworie, F.N. Decentralized Anaerobic Digestion Technology for Improved Management of Human Excreta in Nigeria. 2022, 137–163. [CrossRef]
14. Ihoeghian, N.A.; Amenaghawon, A.N.; Ajieh, M.U.; Oshoma, C.E.; Ogofure, A.; Erhunmwunse, N.O.; Edosa, V.I.O.; Tongo, I.; Obuekwe, I.S.; Isagba, E.S.; et al. Anaerobic Co-Digestion of Cattle Rumen Content and Food Waste for Biogas Production: Establishment of Co-Digestion Ratios and Kinetic Studies. Bioresour Technol Rep 2022, 18, 101033. [CrossRef]
15. Liu, H.; Li, X.; Zhang, Z.; Nghiem, L.D.; Wang, Q. Urine Pretreatment Significantly Promotes Methane Production in Anaerobic Waste Activated Sludge Digestion. Science of The Total Environment 2022, 853, 158684. [CrossRef]
16. Oa, Y.L.S. Resource-Recovery Processes from Animal Waste as Best Available Technology. J Mater Cycles Waste Manag 2015. [CrossRef]
17. Orner, K.D.; Mihelcic, J.R. A Review of Sanitation Technologies to Achieve Multiple Sustainable Development Goals That Promote Resource Recovery. Environ Sci (Camb) 2018, 4, 16–32. [CrossRef]
18. Ranjan, P.; Daya, R.; Pandey, S.; Haynes, M.; Caitlin, P.; Luís, H.; Manuel, C.; Umapathi, R.; Mukherjee, S.; Panigrahi, S. Sustainable Valorisation of Animal Manures via Thermochemical Conversion Technologies : An Inclusive Review on Recent Trends. Waste Biomass Valorization 2022. [CrossRef]
19. Olugasa, T.T.; Odesola, I.F.; Oyewola, M.O. Energy Production from Biogas: A Conceptual Review for Use in Nigeria. Renewable and Sustainable Energy Reviews 2014, 32, 770–776. [CrossRef]
20. Adebayo, G.; Malomo, A. Sustainable Animal Animal Manure Manure Management Management Strategies Strategies and Practices. 2018. [CrossRef]
21. Zseni, A. Human Excreta Management : Human Excreta as an Important Base of Sustainable Agriculture. 2015.
22. Chen, W.T.C.H.H. Pyrolytic Conversion of Horse Manure into Biochar and Its Thermochemical and Physical Properties. Waste Biomass Valorization 2015. [CrossRef]
23. Afolabi, I.C.; Emmanuel, E.I.; Gunes, B.; Okolie, J.A. Data-Driven Machine Learning Approach for Predicting the Higher Heating Value of Different Biomass Classes. SSRN Electronic Journal 2022, 4, 1227–1241. [CrossRef]
24. Shen, X.; Huang, G.; Yang, Z.; Han, L. Compositional Characteristics and Energy Potential of Chinese Animal Manure by Type and as a Whole. Appl Energy 2015, 160, 108–119. [CrossRef]
25. Shen, X.; Huang, G.; Yang, Z.; Han, L. Compositional Characteristics and Energy Potential of Chinese Animal Manure by Type and as a Whole. Appl Energy 2015, 160, 108–119. [CrossRef]
26. Hussein, M.S.; Burra, K.G.; Amano, R.S.; Gupta, A.K. Temperature and Gasifying Media Effects on Chicken Manure Pyrolysis and Gasification. Fuel 2017, 202, 36–45. [CrossRef]
27. Yacob, T.W.; Chip, R.; Linden, K.G.; Weimer, A.W. Pyrolysis of Human Feces : Gas Yield Analysis and Kinetic Modeling. Waste Management 2018, 79, 214–222. [CrossRef]
28. Nitsche, M.; Hensgen, F.; Wachendorf, M. Energy Generation from Horse Husbandry Residues by Anaerobic Digestion, Combustion, and an Integrated Approach. 2017. [CrossRef]
29. Chong, C.T.; Mong, G.R.; Ng, J.H.; Chong, W.W.F.; Ani, F.N.; Lam, S.S.; Ong, H.C. Pyrolysis Characteristics and Kinetic Studies of Horse Manure Using Thermogravimetric Analysis. Energy Convers Manag 2019, 180, 1260–1267. [CrossRef]
30. Wu, Q.; Wang, H.; Zheng, X.; Liu, F.; Wang, A. Thermochemical Liquefaction of Pig Manure : Factors in Fl Uencing on Oil. 2020, 264. [CrossRef]
31. Nazrul, M.; Park, I.J.; Korea, B.Á.E.Á.S. A Short Review on Hydrothermal Liquefaction of Livestock Manure and a Chance for Korea to Advance Swine Manure to Bio-Oil Technology. J Mater Cycles Waste Manag 2016. [CrossRef]
32. Salana, S.; Banerji, T.; Kumar, A.; Singh, E.; Kumar, S. Resource Recovery-Oriented Sanitation and Sustainable Human Excreta Management. 2021, 109–136.
33. Rose, C.; Parker, A.; Jefferson, B.; Cartmell, E. The Characterization of Feces and Urine : A Review of the Literature to Inform Advanced Treatment Technology. 2015, 1827–1879. [CrossRef]
34. Salana, S.; Banerji, T.; Kumar, A.; Singh, E.; Kumar, S. Resource Recovery-Oriented Sanitation and Sustainable Human Excreta Management. 2021, 109–136.
35. Biswas, J.K.; Rana, S.; Meers, E. Bioregenerative Nutrient Recovery from Human Urine : Closing the Loop in Turning Waste into Wealth.
36. Simha, P.; Ganesapillai, M. Ecological Sanitation and Nutrient Recovery from Human Urine: How Far Have We Come? A Review. Sustainable Environment Research 2017. [CrossRef]
37. Simha, P.; Ganesapillai, M. Ecological Sanitation and Nutrient Recovery from Human Urine: How Far Have We Come? A Review. Sustainable Environment Research 2017. [CrossRef]
38. Shanableh, A.; Abdallah, M.; Tayara, A.; Ghenai, C.; Kamil, M.; Inayat, A.; Shabib, A. Experimental Characterization and Assessment of Bio- and Thermo-Chemical Energy Potential of Dromedary Manure. Biomass Bioenergy 2021, 148, 106058. [CrossRef]
39. Okolie, J.A.; Epelle, E.I.; Tabat, M.E.; Orivri, U.; Amenaghawon, A.N.; Okoye, P.U.; Gunes, B. Waste Biomass Valorization for the Production of Biofuels and Value-Added Products: A Comprehensive Review of Thermochemical, Biological and Integrated Processes. Process Safety and Environmental Protection 2022, 159, 323–344. [CrossRef]
40. Perera, S.M.H.D.; Wickramasinghe, C.; Samarasiri, B.K.T.; Narayana, M. Modeling of Thermochemical Conversion of Waste Biomass—a Comprehensive Review. 2021, 32, 1481–1528. [CrossRef]
41. Jha, S.; Nanda, S.; Acharya, B.; Dalai, A.K. A Review of Thermochemical Conversion of Waste Biomass to Biofuels. 2022, 1–23.
42. Rowles, L.S.; Morgan, V.L.; Li, Y.; Zhang, X.; Watabe, S.; Stephen, T.; Lohman, H.A.C.; Desouza, D.; Hallowell, J.; Cusick, R.D.; et al. Financial Viability and Environmental Sustainability of Fecal Sludge Treatment with Pyrolysis Omni Processors. ACS Environmental Au 2022, 2, 455–466. [CrossRef]
43. Selim, O.M.; Amano, R.S. Co-Pyrolysis of Chicken and Cow Manure. Journal of Energy Resources Technology, Transactions of the ASME 2021, 143. [CrossRef]
44. Beik, F.; Williams, L.; Brown, T.; Wagland, S.T. Development and Prototype Testing of a Novel Small-Scale Pyrolysis System for the Treatment of Sanitary Sludge. Energy Convers Manag 2023, 277, 116627. [CrossRef]
45. Wang, Q.; Ren, X.; Sun, Y.; Zhao, J.; Awasthi, M.K.; Liu, T.; Li, R.; Zhang, Z. Improvement of the Composition and Humification of Different Animal Manures by Black Soldier Fly Bioconversion. J Clean Prod 2021, 278, 123397. [CrossRef]
46. Cantrell, K.; Ro, K.; Mahajan, D.; Anjom, M.; Hunt, P.G. Role of Thermochemical Conversion in Livestock Waste-to-Energy Treatments : Obstacles and Opportunities. 2007, 8918–8927.
47. Cantrell, K.B.; Hunt, P.G.; Uchimiya, M.; Novak, J.M.; Ro, K.S. Bioresource Technology Impact of Pyrolysis Temperature and Manure Source on Physicochemical Characteristics of Biochar. Bioresour Technol 2012, 107, 419–428. [CrossRef]
48. Lee, D.J.; Jung, S.; Jeong, K.H.; Lee, D.H.; Lee, S.H.; Park, Y.K.; Kwon, E.E. Catalytic Pyrolysis of Cow Manure over a Ni/SiO2 Catalyst Using CO2 as a Reaction Medium. Energy 2020, 195, 117077. [CrossRef]
49. Krounbi, L.; Enders, A.; Es, H. Van; Woolf, D.; Herzen, B. Van; Lehmann, J. Biological and Thermochemical Conversion of Human Solid Waste to Soil Amendments. Waste Management 2019, 89, 366–378. [CrossRef]
50. Yacob, T.W.; Chip, R.; Linden, K.G.; Weimer, A.W. Pyrolysis of Human Feces : Gas Yield Analysis and Kinetic Modeling. Waste Management 2018, 79, 214–222. [CrossRef]
51. Mong, G.R.; Chong, C.T.; Ng, J.H.; Chong, W.W.F.; Ong, H.C.; Tran, M.V. Multivariate Optimisation Study and Life Cycle Assessment of Microwave-Induced Pyrolysis of Horse Manure for Waste Valorisation and Management. Energy 2021, 216, 119194. [CrossRef]
52. Liu, X.; Li, Z.; Zhang, Y.; Feng, R.; Mahmood, I.B. Characterization of Human Manure-Derived Biochar and Energy-Balance Analysis of Slow Pyrolysis Process. Waste Management 2014, 34, 1619–1626. [CrossRef]
53. Zhou, S.; Liang, H.; Han, L.; Huang, G.; Yang, Z. The Influence of Manure Feedstock, Slow Pyrolysis, and Hydrothermal Temperature on Manure Thermochemical and Combustion Properties. Waste Management 2019, 88, 85–95. [CrossRef]
54. Al-Salem, S.M.; Antelava, A.; Constantinou, A.; Manos, G.; Dutta, A. A Review on Thermal and Catalytic Pyrolysis of Plastic Solid Waste (PSW). J Environ Manage 2017, 197, 177–198. [CrossRef]
55. Al-Salem, S.M.; Antelava, A.; Constantinou, A.; Manos, G.; Dutta, A. A Review on Thermal and Catalytic Pyrolysis of Plastic Solid Waste (PSW). J Environ Manage 2017, 197, 177–198. [CrossRef]
56. Bleuler, M.; Gold, M.; Strande, L.; Schönborn, A. Pyrolysis of Dry Toilet Substrate as a Means of Nutrient Recycling in Agricultural Systems: Potential Risks and Benefits. Waste Biomass Valorization 2021, 12, 4171–4183. [CrossRef]
57. Koutcheiko, S. Preparation and Characterization of Activated Carbon Derived from the Thermo-Chemical Conversion of Chicken Manure. 2007, 98, 2459–2464. [CrossRef]
58. Emrah, A.; Polat, R.; Ozbay, G. Engineering Science and Technology, an International Journal Pyrolysis of Goat Manure to Produce Bio-Oil. Engineering Science and Technology, an International Journal 2018. [CrossRef]
59. Elkasabi, Y.; Mullen, C.A.; Pighinelli, A.L.M.T.; Boateng, A.A. Hydrodeoxygenation of Fast-Pyrolysis Bio-Oils from Various Feedstocks Using Carbon-Supported Catalysts. Fuel Processing Technology 2014, 123, 11–18. [CrossRef]
60. Pandey, D.S.; Katsaros, G.; Lindfors, C.; Leahy, J.J.; Tassou, S.A. Fast Pyrolysis of Poultry Litter in a Bubbling Fluidised Bed Reactor: Energy and Nutrient Recovery. Sustainability (Switzerland) 2019, 11, 2533. [CrossRef]
61. Mong, G.R.; Chong, C.T.; Ng, J.H.; Chong, W.W.F.; Lam, S.S.; Ong, H.C.; Ani, F.N. Microwave Pyrolysis for Valorisation of Horse Manure Biowaste. Energy Convers Manag 2020, 220, 113074. [CrossRef]
62. Lee, D.J.; Jung, S.; Jang, Y.N.; Jo, G.; Park, S.H.; Jeon, Y.J.; Park, Y.K.; Kwon, E.E. Offering a New Option to Valorize Hen Manure by CO2-Assisted Catalytic Pyrolysis over Biochar and Metal Catalysts. Journal of CO2 Utilization 2020, 42, 101344. [CrossRef]
63. He, S.; Cao, C.; Wang, J.; Yang, J.; Cheng, Z.; Yan, B.; Pan, Y.; Chen, G. Pyrolysis Study on Cattle Manure: From Conventional Analytical Method to Online Study of Pyrolysis Photoionization Time-of-Flight Mass Spectrometry. J Anal Appl Pyrolysis 2020, 151, 104916. [CrossRef]
64. Ren, C.; Guo, S.; Wang, Y.; Liu, S.; Du, M.; Chen, Y.; Guo, L. Thermodynamic Analysis and Optimization of Auto-Thermal Supercritical Water Gasification Polygeneration System of Pig Manure. Chemical Engineering Journal 2022, 427, 131938. [CrossRef]
65. Onabanjo, T.; Patchigolla, K.; Wagland, S.T.; Fidalgo, B.; Kolios, A.; McAdam, E.; Parker, A.; Williams, L.; Tyrrel, S.; Cartmell, E. Energy Recovery from Human Faeces via Gasification: A Thermodynamic Equilibrium Modelling Approach. Energy Convers Manag 2016, 118, 364–376. [CrossRef]
66. Parthasarathy, P.; Fernandez, A.; Al-Ansari, T.; Mackey, H.R.; Rodriguez, R.; McKay, G. Thermal Degradation Characteristics and Gasification Kinetics of Camel Manure Using Thermogravimetric Analysis. J Environ Manage 2021, 287, 112345. [CrossRef]
67. Sobamowo, G.M.; Ojolo, S.J. Techno-Economic Analysis of Biomass Energy Utilization through Gasification Technology for Sustainable Energy Production and Economic Development in Nigeria. Journal of Energy 2018, 2018, 1–16. [CrossRef]
68. Jia, J.; Shu, L.; Zang, G.; Xu, L.; Abudula, A.; Ge, K. Energy Analysis and Techno-Economic Assessment of a Co-Gasification of Woody Biomass and Animal Manure, Solid Oxide Fuel Cells and Micro Gas Turbine Hybrid System. Energy 2018, 149, 750–761. [CrossRef]
69. Liu, M.; Li, F.; Liu, H.; Wang, C. Synergistic Effect on Co-Gasification of Chicken Manure and Petroleum Coke : An Investigation of Sustainable Waste Management. Chemical Engineering Journal 2020, 128008. [CrossRef]
70. Onabanjo, T.; Patchigolla, K.; Wagland, S.T.; Fidalgo, B.; Kolios, A.; McAdam, E.; Parker, A.; Williams, L.; Tyrrel, S.; Cartmell, E. Energy Recovery from Human Faeces via Gasification: A Thermodynamic Equilibrium Modelling Approach. Energy Convers Manag 2016, 118, 364–376. [CrossRef]
71. Hussein, M.S.; Burra, K.G.; Amano, R.S.; Gupta, A.K. Temperature and Gasifying Media Effects on Chicken Manure Pyrolysis and Gasification. Fuel 2017, 202, 36–45. [CrossRef]
72. Xin, Y.; Cao, H.; Yuan, Q.; Wang, D. Two-Step Gasification of Cattle Manure for Hydrogen-Rich Gas Production : Effect of Biochar Preparation Temperature and Gasification Temperature. Waste Management 2017. [CrossRef]
73. Nanda, S.; Dalai, A.K.; Gökalp, I.; Kozinski, J.A. Valorization of Horse Manure through Catalytic Supercritical Water Gasification. Waste Management 2016, 52, 147–158. [CrossRef]
74. Tavasoli, A.; Aslan, M.; Salimi, M.; Balou, S.; Pirbazari, S.M.; Hashemi, H.; Kohansal, K. Influence of the Blend Nickel/Porous Hydrothermal Carbon and Cattle Manure Hydrochar Catalyst on the Hydrothermal Gasification of Cattle Manure for H2 Production. Energy Convers Manag 2018, 173, 15–28. [CrossRef]
75. Liu, S.; Cao, W.; Wang, Y.; Wei, W.; Li, L.; Jin, H.; Guo, L. Characteristics and Mechanisms of Nitrogen Transformation during Chicken Manure Gasification in Supercritical Water. Waste Management 2022, 153, 240–248. [CrossRef]
76. de Blasio, C. Notions of Biomass Gasification. Green Energy and Technology 2019, 307–334.
77. Liu, S.; Cao, W.; Wang, Y.; Wei, W.; Li, L.; Jin, H.; Guo, L. Characteristics and Mechanisms of Nitrogen Transformation during Chicken Manure Gasification in Supercritical Water. Waste Management 2022, 153, 240–248. [CrossRef]
78. Salierno, G.; Marinelli, F.; Likozar, B.; Ghavami, N.; de Blasio, C. Supercritical Water Gasification of Glycerol: Continuous Reactor Kinetics and Transport Phenomena Modeling. Int J Heat Mass Transf 2022, 183, 122200. [CrossRef]
79. Pandey, D.S.; Kwapinska, M.; Barea, A.G.; Horvat, A.; Fryda, L.E.; Rabou, L.P.L.M.; Leahy, J.J.; Kwapinski, W. Poultry Litter Gasification in a Fluidized Bed Reactor : Effects of Gasifying Agent and Limestone Addition Poultry Litter Gasification in a Fluidized Bed Reactor : Effects of Gasifying Agent and Limestone Addition. 2016. [CrossRef]
80. Xin, Y.; Cao, H.; Yuan, Q.; Wang, D. Two-Step Gasification of Cattle Manure for Hydrogen-Rich Gas Production : Effect of Biochar Preparation Temperature and Gasification Temperature. Waste Management 2017. [CrossRef]
81. Nanda, S.; Dalai, A.K.; Gökalp, I.; Kozinski, J.A. Valorization of Horse Manure through Catalytic Supercritical Water Gasification. Waste Management 2016, 52, 147–158. [CrossRef]
82. Xiao, X.; Cao, J.; Meng, X.; Le, D.D.; Li, L.; Ogawa, Y.; Sato, K.; Takarada, T. Synthesis Gas Production from Catalytic Gasification of Waste Biomass Using Nickel-Loaded Brown Coal Char. Fuel 2013, 103, 135–140. [CrossRef]
83. Nazrul, M.; Park, I.J.; Korea, B.Á.E.Á.S. A Short Review on Hydrothermal Liquefaction of Livestock Manure and a Chance for Korea to Advance Swine Manure to Bio-Oil Technology. J Mater Cycles Waste Manag 2016. [CrossRef]
84. Perera, S.M.H.D.; Wickramasinghe, C.; Samarasiri, B.K.T.; Narayana, M. Modeling of Thermochemical Conversion of Waste Biomass—a Comprehensive Review. 2021, 32, 1481–1528. [CrossRef]
85. Güleç, F.; Riesco, L.M.G.; Williams, O.; Kostas, E.T.; Samson, A.; Lester, E. Hydrothermal Conversion of Different Lignocellulosic Biomass Feedstocks—Effect of the Process Conditions on Hydrochar Structures. Fuel 2021, 302, 121166. [CrossRef]
86. Castello, D.; Pedersen, T.H. Continuous Hydrothermal Liquefaction of Biomass : A Critical Review. 2018. [CrossRef]
87. Lu, J.; Li, H.; Zhang, Y.; Liu, Z. Nitrogen Migration and Transformation during Hydrothermal Liquefaction of Livestock Manures. ACS Sustain Chem Eng 2018, 6, 13570–13578. [CrossRef]
88. Güleç, F.; Riesco, L.M.G.; Williams, O.; Kostas, E.T.; Samson, A.; Lester, E. Hydrothermal Conversion of Different Lignocellulosic Biomass Feedstocks—Effect of the Process Conditions on Hydrochar Structures. Fuel 2021, 302, 121166. [CrossRef]
89. Conti, F.; Toor, S.S.; Pedersen, T.H.; Seehar, T.H.; Nielsen, A.H. Valorization of Animal and Human Wastes through Hydrothermal Liquefaction for Biocrude Production and Simultaneous Recovery of Nutrients. Energy Convers Manag 2020, 216, 112925. [CrossRef]
90. Conti, F.; Toor, S.S.; Pedersen, T.H.; Seehar, T.H.; Nielsen, A.H. Valorization of Animal and Human Wastes through Hydrothermal Liquefaction for Biocrude Production and Simultaneous Recovery of Nutrients. Energy Convers Manag 2020, 216, 112925. [CrossRef]
91. Li, H.; Lu, J.; Zhang, Y.; Liu, Z. Hydrothermal Liquefaction of Typical Livestock Manures in China: Biocrude Oil Production and Migration of Heavy Metals. J Anal Appl Pyrolysis 2018, 135, 133–140. [CrossRef]
92. Wu, Q.; Wang, H.; Zheng, X.; Liu, F.; Wang, A. Thermochemical Liquefaction of Pig Manure : Factors in Fl Uencing on Oil. 2020, 264. [CrossRef]
93. Wei, L.; Sevilla, M.; Fuertes, A.B.; Mokaya, R.; Yushin, G. Hydrothermal Carbonization of Abundant Renewable Natural Organic Chemicals for High-Performance Supercapacitor Electrodes. Adv Energy Mater 2011, 1, 356–361. [CrossRef]
94. Álvarez-Murillo, A.; Sabio, E.; Ledesma, B.; Román, S.; González-García, C.M. Generation of Biofuel from Hydrothermal Carbonization of Cellulose. Kinetics Modelling. Energy 2016, 94, 600–608. [CrossRef]
95. Kambo, H.S.; Dutta, A. Strength, Storage, and Combustion Characteristics of Densified Lignocellulosic Biomass Produced via Torrefaction and Hydrothermal Carbonization. Appl Energy 2014, 135, 182–191. [CrossRef]
96. Subedi, R.; Kammann, C.; Pelisseti, S.; Sacco, D.; Grignani, C.; Monaco, S. Recycling of Organic Residues for Agriculture: From Waste Management to Ecosystem Services. Available online: https://scholar.google.com/scholar_lookup?title=Recycling%20of%20organic%20residues%20for%20agriculture%3A%20from%20waste%20management%20to%20ecosystem%20services&author=R.%20Subedi&publication_year=2013 (accessed on 18 January 2023).
97. Guangzhi, Y.; Jinyu, Y.; Yuhua, Y.; Zhihong, T.; DengGuang, Y.; Junhe, Y. Preparation and CO2 Adsorption Properties of Porous Carbon from Camphor Leaves by Hydrothermal Carbonization and Sequential Potassium Hydroxide Activation. RSC Adv 2017, 7, 4152–4160. [CrossRef]
98. Liu, Z.; Zhang, F.; Hoekman, S.K.; Liu, T.; Gai, C.; Peng, N. Homogeneously Dispersed Zerovalent Iron Nanoparticles Supported on Hydrochar-Derived Porous Carbon: Simple, in Situ Synthesis and Use for Dechlorination of PCBs. ACS Sustain Chem Eng 2016, 4, 3261–3267.
99. Fan, F.; Xing, X.; Shi, S.; Zhang, X.; Zhang, X.; Li, Y.; Xing, Y. Combustion Characteristic and Kinetics Analysis of Hydrochars. Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering 2016, 32, 219–224.
100. Hao, W.; Björkman, E.; Lilliestråle, M.; Hedin, N. Activated Carbons for Water Treatment Prepared by Phosphoric Acid Activation of Hydrothermally Treated Beer Waste. Ind Eng Chem Res 2014, 53, 15389–15397.
101. Titirici, M.M.; Antonietti, M.; Baccile, N. Hydrothermal Carbon from Biomass: A Comparison of the Local Structure from Poly- to Monosaccharides and Pentoses/Hexoses. Green Chemistry 2008, 10, 1204–1212. [CrossRef]
102. Yahav Spitzer, R.; Mau, V.; Gross, A. Using Hydrothermal Carbonization for Sustainable Treatment and Reuse of Human Excreta. J Clean Prod 2018, 205, 955–963. [CrossRef]
103. Afolabi, O.O.D.; Sohail, M.; Thomas, C.P.L. Microwave Hydrothermal Carbonization of Human Biowastes. Waste Biomass Valorization 2015, 6, 147–157.
104. Danso-Boateng, E.; Holdich, R.G.; Martin, S.J.; Shama, G.; Wheatley, A.D. Process Energetics for the Hydrothermal Carbonisation of Human Faecal Wastes. Energy Convers Manag 2015, 105, 1115–1124. [CrossRef]
105. Czerwińska, K.; Śliz, M.; Wilk, M. Hydrothermal Carbonization Process: Fundamentals, Main Parameter Characteristics and Possible Applications Including an Effective Method of SARS-CoV-2 Mitigation in Sewage Sludge. A Review. Renewable and Sustainable Energy Reviews 2022, 154, 111873. [CrossRef]
106. Jang, E.S.; Ryu, D.Y.; Kim, D. Hydrothermal Carbonization Improves the Quality of Biochar Derived from Livestock Manure by Removing Inorganic Matter. Chemosphere 2022, 305, 135391. [CrossRef]
107. Qaramaleki, S. v.; Villamil, J.A.; Mohedano, A.F.; Coronella, C.J. Factors Affecting Solubilization of Phosphorus and Nitrogen through Hydrothermal Carbonization of Animal Manure. ACS Sustain Chem Eng 2020, 8, 12462–12470.
108. Ghavami, N.; Özdenkçi, K.; Chianese, S.; Musmarra, D.; de Blasio, C. Process Simulation of Hydrothermal Carbonization of Digestate from Energetic Perspectives in Aspen Plus. Energy Convers Manag 2022, 270, 116215. [CrossRef]
109. Wang, W.; Yang, L.; Yin, Z.; Kong, S.; Han, W.; Zhang, J. Catalytic Liquefaction of Human Feces over Ni-Tm/TiO2 Catalyst and the Influence of Operating Conditions on Products. Energy Convers Manag 2018, 157, 239–245. [CrossRef]
110. Li, H.; Lu, J.; Zhang, Y.; Liu, Z. Hydrothermal Liquefaction of Typical Livestock Manures in China: Biocrude Oil Production and Migration of Heavy Metals. J Anal Appl Pyrolysis 2018, 135, 133–140. [CrossRef]
111. Alherbawi, M.; Parthasarathy, P.; Al-Ansari, T.; Mackey, H.R.; McKay, G. Potential of Drop-in Biofuel Production from Camel Manure by Hydrothermal Liquefaction and Biocrude Upgrading: A Qatar Case Study. Energy 2021, 232, 121027. [CrossRef]
112. He, S.; Wang, J.; Cheng, Z.; Dong, H.; Yan, B.; Chen, G. Synergetic Effect and Primary Reaction Network of Corn Cob and Cattle Manure in Single and Mixed Hydrothermal Liquefaction. J Anal Appl Pyrolysis 2021, 155, 105076. [CrossRef]
113. Neshat, S.A.; Mohammadi, M.; Najafpour, G.D.; Lahijani, P. Anaerobic Co-Digestion of Animal Manures and Lignocellulosic Residues as a Potent Approach for Sustainable Biogas Production. Renewable and Sustainable Energy Reviews 2017, 79, 308–322. [CrossRef]
114. Neshat, S.A.; Mohammadi, M.; Najafpour, G.D.; Lahijani, P. Anaerobic Co-Digestion of Animal Manures and Lignocellulosic Residues as a Potent Approach for Sustainable Biogas Production. Renewable and Sustainable Energy Reviews 2017, 79, 308–322. [CrossRef]
115. Lee, S.Y.; Sankaran, R.; Chew, K.W.; Tan, C.H.; Krishnamoorthy, R. BMC Energy Waste to Bioenergy : A Review on the Recent Conversion Technologies. 2019, 1–22.
116. Zhang, Y.; Cui, Y.; Chen, P.; Liu, S. Gasi Fi Cation Technologies and Their Energy Potentials; Elsevier B.V., 2019; ISBN 9780444642004.
117. Lee, S.Y.; Sankaran, R.; Chew, K.W.; Tan, C.H.; Krishnamoorthy, R. BMC Energy Waste to Bioenergy : A Review on the Recent Conversion Technologies. 2019, 1–22.
118. Karki, R.; Chuenchart, W.; Surendra, K.C.; Shrestha, S.; Raskin, L.; Sung, S.; Hashimoto, A.; Kumar Khanal, S. Anaerobic Co-Digestion: Current Status and Perspectives. Bioresour Technol 2021, 330, 125001. [CrossRef]
119. Dalke, R.; Demro, D.; Khalid, Y.; Wu, H.; Urgun-Demirtas, M. Current Status of Anaerobic Digestion of Food Waste in the United States. Renewable and Sustainable Energy Reviews 2021, 151, 111554. [CrossRef]
120. Ilo, O.P.; Simatele, M.D.; Nkomo, S.L.; Mkhize, N.M.; Prabhu, N.G. Methodological Approaches to Optimising Anaerobic Digestion of Water Hyacinth for Energy Efficiency in South Africa. Sustainability 2021, 13, 6746. [CrossRef]
121. Ripoll, V.; Agabo-García, C.; Solera, R.; Perez, M. Anaerobic Digestion of Slaughterhouse Waste in Batch and Anaerobic Sequential Batch Reactors. Biomass Convers Biorefin 2022, 1–12. [CrossRef]
122. Rajendran, K.; Mahapatra, D.; Venkatraman, A.V.; Muthuswamy, S.; Pugazhendhi, A. Advancing Anaerobic Digestion through Two-Stage Processes: Current Developments and Future Trends. Renewable and Sustainable Energy Reviews 2020, 123, 109746. [CrossRef]
123. Donkor, K.O.; Gottumukkala, L.D.; Lin, R.; Murphy, J.D. A Perspective on the Combination of Alkali Pre-Treatment with Bioaugmentation to Improve Biogas Production from Lignocellulose Biomass. Bioresour Technol 2022, 351, 126950. [CrossRef]
124. Awosusi, A.; Sethunya, V.; Matambo, T. Synergistic Effect of Anaerobic Co-Digestion of South African Food Waste with Cow Manure: Role of Low Density-Polyethylene in Process Modulation. Mater Today Proc 2021, 38, 793–803. [CrossRef]
125. Ihoeghian, N.A.; Amenaghawon, A.N.; Ajieh, M.U.; Oshoma, C.E.; Ogofure, A.; Erhunmwunse, N.O.; Edosa, V.I.O.; Tongo, I.; Obuekwe, I.S.; Isagba, E.S.; et al. Anaerobic Co-Digestion of Cattle Rumen Content and Food Waste for Biogas Production: Establishment of Co-Digestion Ratios and Kinetic Studies. Bioresour Technol Rep 2022, 18, 101033. [CrossRef]
126. Ma, G.; Ndegwa, P.; Harrison, J.H.; Chen, Y. Methane Yields during Anaerobic Co-Digestion of Animal Manure with Other Feedstocks: A Meta-Analysis. Science of the Total Environment 2020, 728, 138224. [CrossRef]
127. Ma, G.; Ndegwa, P.; Harrison, J.H.; Chen, Y. Methane Yields during Anaerobic Co-Digestion of Animal Manure with Other Feedstocks: A Meta-Analysis. Science of the Total Environment 2020, 728, 138224. [CrossRef]
128. Adjama, I.; Sarfo, N.; Derkyi, A.; Uba, F.; Akolgo, G.A.; Opuko, R. Anaerobic Co-Digestion of Human Feces with Rice Straw for Biogas Production : A Case Study in Sunyani. 2022, 2022.
129. Kaur, H.; Kommalapati, R.R. Optimizing Anaerobic Co-Digestion of Goat Manure and Cotton Gin Trash Using Biochemical Methane Potential (BMP) Test and Mathematical Modeling. SN Appl Sci 2021, 3, 1–14.
130. Alfa, M.I.; Owamah, H.I.; Onokwai, A.O.; Gopikumar, S.; Oyebisi, S.O.; Kumar, S.S.; Bajar, S.; Samuel, O.D.; Ilabor, S.C. Evaluation of Biogas Yield and Kinetics from the Anaerobic Co-Digestion of Cow Dung and Horse Dung: A Strategy for Sustainable Management of Livestock Manure. Energy, Ecology and Environment 2020 6:5 2020, 6, 425–434. [CrossRef]
131. Hamzah, A.F.A.; Hamzah, M.H.; Man, H.C.; Jamali, N.S.; Siajam, S.I.; Show, P.L. Biogas Production Through Mono- and Co-Digestion of Pineapple Waste and Cow Dung at Different Substrate Ratios. Bioenergy Res 2022, 1, 1–12. [CrossRef]
132. Arifan, F.; Sumardiono, S. EFFECTIVENESS ANALYSIS OF ANAEROBIC DIGESTION METHOD IN MAKING BIOGAS FROM ANIMAL MANURE AND. 2021, 16, 84–94.
133. Arifan, F.; Sumardiono, S. EFFECTIVENESS ANALYSIS OF ANAEROBIC DIGESTION METHOD IN MAKING BIOGAS FROM ANIMAL MANURE AND. 2021, 16, 84–94.
134. Silwadi, M.; Mousa, H.; AL-Hajji, B.Y.; AL-Wahaibi, S.S.; AL-Harrasi, Z.Z. Enhancing Biogas Production by Anaerobic Digestion of Animal Manure. Int J Green Energy 2022. [CrossRef]
135. Ren, Y.; Yu, M.; Wu, C.; Wang, Q.; Gao, M.; Huang, Q.; Liu, Y. A Comprehensive Review on Food Waste Anaerobic Digestion: Research Updates and Tendencies. Bioresour Technol 2018, 247, 1069–1076. [CrossRef]
136. Xu, H.; Chang, J.; Wang, H.; Liu, Y.; Zhang, X.; Liang, P.; Huang, X. Enhancing Direct Interspecies Electron Transfer in Syntrophic-Methanogenic Associations with (Semi)Conductive Iron Oxides: Effects and Mechanisms. Science of The Total Environment 2019, 695, 133876. [CrossRef]
137. Lv, N.; Zhao, L.; Wang, R.; Ning, J.; Pan, X.; Li, C.; Cai, G.; Zhu, G. Novel Strategy for Relieving Acid Accumulation by Enriching Syntrophic Associations of Syntrophic Fatty Acid-Oxidation Bacteria and H2/Formate-Scavenging Methanogens in Anaerobic Digestion. Bioresour Technol 2020, 313, 123702. [CrossRef]
138. Wang, P.; Peng, H.; Adhikari, S.; Higgins, B.; Roy, P.; Dai, W.; Shi, X. Enhancement of Biogas Production from Wastewater Sludge via Anaerobic Digestion Assisted with Biochar Amendment. Bioresour Technol 2020, 309, 123368. [CrossRef]
139. Zhang, L.; Tsui, T.H.; Loh, K.C.; Dai, Y.; Tong, Y.W. Effects of Plastics on Reactor Performance and Microbial Communities during Acidogenic Fermentation of Food Waste for Production of Volatile Fatty Acids. Bioresour Technol 2021, 337, 125481. [CrossRef]
140. Arif, S.; Liaquat, R.; Adil, M. Applications of Materials as Additives in Anaerobic Digestion Technology. Renewable and Sustainable Energy Reviews 2018, 97, 354–366. [CrossRef]
141. Sitthi, S.; Hatamoto, M.; Watari, T.; Yamaguchi, T. Enhancing Anaerobic Syntrophic Propionate Degradation Using Modified Polyvinyl Alcohol Gel Beads. Heliyon 2020, 6, e05665. [CrossRef]
142. Zhao, J.; Li, Y.; Euverink, G.J.W. Effect of Bioaugmentation Combined with Activated Charcoal on the Mitigation of Volatile Fatty Acids Inhibition during Anaerobic Digestion. Chemical Engineering Journal 2022, 428, 131015. [CrossRef]
143. Lu, X.; Wang, H.; Ma, F.; Zhao, G.; Wang, S. Improved Process Performance of the Acidification Phase in a Two-Stage Anaerobic Digestion of Complex Organic Waste: Effects of an Iron Oxide-Zeolite Additive. Bioresour Technol 2018, 262, 169–176. [CrossRef]
144. Zhang, J.; Cui, Y.; Zhang, T.; Hu, Q.; Wah Tong, Y.; He, Y.; Dai, Y.; Wang, C.H.; Peng, Y. Food Waste Treating by Biochar-Assisted High-Solid Anaerobic Digestion Coupled with Steam Gasification: Enhanced Bioenergy Generation and Porous Biochar Production. Bioresour Technol 2021, 331, 125051. [CrossRef]
145. Adjama, I.; Sarfo, N.; Derkyi, A.; Uba, F.; Akolgo, G.A.; Opuko, R. Anaerobic Co-Digestion of Human Feces with Rice Straw for Biogas Production : A Case Study in Sunyani. 2022, 2022.
146. Eduok, S.; John, O.; Ita, B.; Inyang, E.; Coulon, F. Enhanced Biogas Production From Anaerobic Co-Digestion of Lignocellulosic Biomass and Poultry Feces Using Source Separated Human Urine as Buffering Agent. 2018, 6, 1–9. [CrossRef]
147. Pan, J.; Ma, J.; Liu, X.; Zhai, L.; Ouyang, X.; Liu, H. Effects of Different Types of Biochar on the Anaerobic Digestion of Chicken Manure. Bioresour Technol 2019, 275, 258–265. [CrossRef]
148. Kizito, S.; Wu, S.; Kipkemoi Kirui, W.; Lei, M.; Lu, Q.; Bah, H.; Dong, R. Evaluation of Slow Pyrolyzed Wood and Rice Husks Biochar for Adsorption of Ammonium Nitrogen from Piggery Manure Anaerobic Digestate Slurry. Science of The Total Environment 2015, 505, 102–112. [CrossRef]
149. Recebli, Z.; Selimli, S.; Ozkaymak, M.; Gonc, O. BIOGAS PRODUCTION FROM ANIMAL MANURE. 2015, 10, 722–729.
150. Zlateva, P.; Terziev, A.; Yordanov, K. Study of Regime Parameters of the Fermenter in the Production of Biogas from Animal Liquid Waste Materials. 2021, 02010.
151. Andreev, N.; Ronteltap, M.; Boincean, B.; Wernli, M.; Zubcov, E.; Bagrin, N.; Borodin, N.; Lens, P.N.L. Lactic Acid Fermentation of Human Urine to Improve Its Fertilizing Value and Reduce Odour Emissions. J Environ Manage 2017, 198, 63–69. [CrossRef]
152. Andreev, N.; Ronteltap, M.; Boincean, B.; Lens, P.N.L. Lactic Acid Fermentation of Human Excreta for Agricultural Application. J Environ Manage 2018, 206, 890–900. [CrossRef]
153. Lee, D.J.; Yim, J.H.; Jung, S.; Jang, M.S.; Jeong, G.T.; Jeong, K.H.; Lee, D.H.; Kim, J.K.; Tsang, Y.F.; Jeon, Y.J.; et al. Valorization of Animal Manure: A Case Study of Bioethanol Production from Horse Manure. Chemical Engineering Journal 2021, 403, 126345. [CrossRef]
154. Eduok, S.; John, O.; Ita, B.; Inyang, E.; Coulon, F. Enhanced Biogas Production From Anaerobic Co-Digestion of Lignocellulosic Biomass and Poultry Feces Using Source Separated Human Urine as Buffering Agent. 2018, 6, 1–9. [CrossRef]
155. Jimenez, J.; Bott, C.; Love, N.; Bratby, J. Source Separation of Urine as an Alternative Solution to Nutrient Management in Biological Nutrient Removal Treatment Plants. Water Environment Research 2015, 87, 2120–2129. [CrossRef]
156. Koffi Konan, F.; Kouame, M.K.; Author, C.; Koffi Félix, K.; Nazo Edith, K.-K.; Théophile, G.; Kotchi Yves, B.; Kouamé Martin, K.; Yao Francis, K.; Kablan, T. Improving Anaerobic Biodigestion of Manioc Wastewater with Human Urine as Co-Substrate. Int J Innov Appl Stud 2013, 2, 335–343.
157. Twizerimana, M.; M’arimi, M.; Nganyi, E.O.; Marimi, M.; Bura, X. Biogas Production from Co-Digestion of Cotton Yarn Waste and Human Urine. Article in Journal of Energy Research and Reviews 2020. [CrossRef]
158. Giwa, A.S.; Xu, H.; Chang, F.; Wu, J.; Li, Y.; Ali, N.; Ding, S.; Wang, K. Effect of Biochar on Reactor Performance and Methane Generation during the Anaerobic Digestion of Food Waste Treatment at Long-Run Operations. J Environ Chem Eng 2019, 7, 103067. [CrossRef]
159. Wienchol, P.; Szle, A.; Ditaranto, M. Waste-to-Energy Technology Integrated with Carbon Capture e Challenges and Opportunities. 2020, 198. [CrossRef]
160. Liu, X.Y.; Wang, J.J.; Nie, J.M.; Wu, N.; Yang, F.; Yang, R.J. Biogas Production of Chicken Manure by Two-Stage Fermentation Process. 2018, 01048, 5–8.
161. Wienchol, P.; Szle, A.; Ditaranto, M. Waste-to-Energy Technology Integrated with Carbon Capture e Challenges and Opportunities. 2020, 198. [CrossRef]
162. Zlateva, P.; Terziev, A.; Yordanov, K. Study of Regime Parameters of the Fermenter in the Production of Biogas from Animal Liquid Waste Materials. 2021, 02010.
163. Recebli, Z.; Selimli, S.; Ozkaymak, M.; Gonc, O. BIOGAS PRODUCTION FROM ANIMAL MANURE. 2015, 10, 722–729.
164. Zhang, A.; He, J.; Shen, Y.; Xu, X.; Liu, Y.; Li, Y.; Wu, S.; Xue, G.; Li, X.; Makinia, J. Enhanced Degradation of Glucocorticoids, a Potential COVID-19 Remedy, by Co-Fermentation of Waste Activated Sludge and Animal Manure: The Role of Manure Type and Degradation Mechanism. Environ Res 2021, 201, 111488. [CrossRef]
165. Andreev, N.; Ronteltap, M.; Boincean, B.; Wernli, M.; Zubcov, E.; Bagrin, N.; Borodin, N.; Lens, P.N.L. Lactic Acid Fermentation of Human Urine to Improve Its Fertilizing Value and Reduce Odour Emissions. J Environ Manage 2017, 198, 63–69. [CrossRef]
166. Lee, D.J.; Yim, J.H.; Jung, S.; Jang, M.S.; Jeong, G.T.; Jeong, K.H.; Lee, D.H.; Kim, J.K.; Tsang, Y.F.; Jeon, Y.J.; et al. Valorization of Animal Manure: A Case Study of Bioethanol Production from Horse Manure. Chemical Engineering Journal 2021, 403, 126345. [CrossRef]
167. Svetlitchnyi, V.A.; Kensch, O.; Falkenhan, D.A.; Korseska, S.G.; Lippert, N.; Prinz, M.; Sassi, J.; Schickor, A.; Curvers, S. Single-Step Ethanol Production from Lignocellulose Using Novel Extremely Thermophilic Bacteria. Biotechnol Biofuels 2013, 6, 1–15. [CrossRef]
168. Doreswamy, R.; Deb, R.; De, S. Potential Use of Piggery Excreta as a Viable Source of Bioethanol Production. J Clean Prod 2021, 316, 128246. [CrossRef]
169. Yan, Q.; Liu, X.; Wang, Y.; Li, H.; Li, Z.; Zhou, L.; Qu, Y.; Li, Z.; Bao, X. Cow Manure as a Lignocellulosic Substrate for Fungal Cellulase Expression and Bioethanol Production. AMB Express 2018, 8, 1–12. [CrossRef]
170. Dadrasnia, A.; Y, E.H.; Ahmed, M.; Lamkaddam, I.U.; Mora, M.; Pons, S.; Llenas, L.; Williams, P.M.; Oatley-radcliffe, D.L. Sustainable Nutrient Recovery from Animal Manure : A Review of Current Best Practice Technology and the Potential for Freeze Concentration. 2021, 315. [CrossRef]
171. Ruiz, D.; San Miguel, G.; Corona, B.; Gaitero, A.; Domínguez, A. Environmental and Economic Analysis of Power Generation in a Thermophilic Biogas Plant. Science of the Total Environment 2018, 633, 1418–1428. [CrossRef]
172. Queiroz, R.F.A.I.D.S.; Oliveira, J.E.R.M.R.C. Enriched Animal Manure as a Source of Phosphorus in Sustainable Agriculture. International Journal of Recycling of Organic Waste in Agriculture 2019, 8, 203–210. [CrossRef]
173. Martin, T.M.P.; Esculier, F.; Levavasseur, F.; Houot, S.; Martin, T.M.P.; Esculier, F.; Levavasseur, F.; Houot, S. Technology Human Urine-Based Fertilizers : A Review. Crit Rev Environ Sci Technol 2020, 0, 1–47. [CrossRef]
174. Sugihara, R. Reuse of Human Excreta in Developing Countries : Agricultural Fertilization Optimization. 2020, 22, 58–64. [CrossRef]
175. Moya, B.; Parker, A.; Sakrabani, R. Challenges to the Use of Fertilisers Derived from Human Excreta : The Case of Vegetable Exports from Kenya to Europe and Influence of Certification Systems. Food Policy 2019, 85, 72–78. [CrossRef]
176. Ajiboye, T.O.; Ogunbiyi, O.D.; Omotola, E.O.; Adeyemi, W.J.; Agboola, O.O.; Onwudiwe, D.C. Results in Engineering Urine : Useless or Useful “ Waste ” ? 2022, 16. [CrossRef]
177. Pathy, A.; Ray, J.; Paramasivan, B. Challenges and Opportunities of Nutrient Recovery from Human Urine Using Biochar for Fertilizer Applications. J Clean Prod 2021, 304, 127019. [CrossRef]
178. Akpan-idiok, A.U.; Asukwo, I.; Ikpi, E. Resources, Conservation and Recycling The Use of Human Urine as an Organic Fertilizer in the Production of Okra (Abelmoschus Esculentus) in South Eastern Nigeria. Resour Conserv Recycl 2012, 62, 14–20. [CrossRef]
179. Pathy, A.; Ray, J.; Paramasivan, B. Challenges and Opportunities of Nutrient Recovery from Human Urine Using Biochar for Fertilizer Applications. J Clean Prod 2021, 304, 127019. [CrossRef]
180. Ajiboye, T.O.; Ogunbiyi, O.D.; Omotola, E.O.; Adeyemi, W.J.; Agboola, O.O.; Onwudiwe, D.C. Results in Engineering Urine : Useless or Useful “ Waste ” ? 2022, 16. [CrossRef]
181. Vaneeckhaute, C.; Lebuf, V.; Michels, E.; Belia, E.; Vanrolleghem, P.A.; Tack, F.M.G.; Meers, E. Nutrient Recovery from Digestate: Systematic Technology Review and Product Classification. Waste Biomass Valorization 2017, 8, 21–40. [CrossRef]
182. Patel, A.; Mungray, A.A.; Mungray, A.K. Technologies for the Recovery of Nutrients, Water and Energy from Human Urine: A Review. Chemosphere 2020, 259, 127372. [CrossRef]
183. Harder, R.; Wielemaker, R.; Larsen, T.A.; Zeeman, G.; Harder, R.; Wielemaker, R.; Larsen, T.A.; Zeeman, G. Technology Recycling Nutrients Contained in Human Excreta to Agriculture : Pathways, Processes, and Products. Crit Rev Environ Sci Technol 2019, 0, 1–49. [CrossRef]
184. Ahmed, N.; Shim, S.; Won, S.; Ra, C. Struvite Recovered from Various Types of Wastewaters: Characteristics, Soil Leaching Behaviour, and Plant Growth. Land Degrad Dev 2018, 29, 2864–2879. [CrossRef]
185. Ahmed, N.; Shim, S.; Won, S.; Ra, C. Struvite Recovered from Various Types of Wastewaters: Characteristics, Soil Leaching Behaviour, and Plant Growth. Land Degrad Dev 2018, 29, 2864–2879. [CrossRef]
186. Papurello, D.; Boschetti, A.; Silvestri, S.; Khomenko, I. Real-Time Monitoring of Removal of Trace Compounds with PTR-MS: Biochar Experimental Investigation. Renew Energy 2018. [CrossRef]
187. Wei, S.P.; Rossum, F. Van; Pol, G.J. Van De; Winkler, M.H. AC SC. ECSN 2018. [CrossRef]
188. Masrura, S.U.; Dissanayake, P.; Sun, Y.; Ok, Y.S.; Tsang, D.C.W.; Khan, E. Technology Sustainable Use of Biochar for Resource Recovery and Pharmaceutical Removal from Human Urine : A Critical Review. Crit Rev Environ Sci Technol 2020, 0, 1–33. [CrossRef]
189. Zhang, J.; She, Q.; Chang, V.W.C.; Tang, C.Y.; Webster, R.D. Mining Nutrients (N, K, P) from Urban Source-Separated Urine by Forward Osmosis Dewatering. 2014.
190. Martin, T.M.P.; Esculier, F.; Levavasseur, F.; Houot, S.; Martin, T.M.P.; Esculier, F.; Levavasseur, F.; Houot, S. Technology Human Urine-Based Fertilizers : A Review. Crit Rev Environ Sci Technol 2020, 0, 1–47. [CrossRef]
191. Azuara, M.; Kersten, S.R.A.; Kootstra, A.M.J. Recycling Phosphorus by Fast Pyrolysis of Pig Manure : Concentration and Extraction of Phosphorus Combined with Formation of Value-Added Pyrolysis Products. Biomass Bioenergy 2012, 49, 171–180. [CrossRef]
192. Chen Chapter 1—Introduction; Metallurgical Industry Press, 2017;
193. Zhang, T.; Bowers, K.E.; Harrison, J.H.; Chen, S. Releasing Phosphorus from Calcium for Struvite Fertilizer Production from Anaerobically Digested Dairy Effluent. 2010, 82. [CrossRef]