Research Progress on Resource Utilization of Livestock and Poultry Manure

Although mass livestock and poultry breeding brought magnificent econom-ic benefits to the society, it made great harm to the environment. By reviewing the current status of environmental pol ution caused by livestock and poultry manure in China, harm-free treatment technology for livestock and poultry manure including fer-tilization technology, feed processing technology and energy technology were elabo-rated so as to address the existing issues in this regard and provide references for resource utilization and eliminating environmental pol ution through modified technical system and environment laws.

Black soldier fly:A new vista for livestock and poultry manure management

The number of intensive livestock and poultry farms is expected to increase substantially in future because of consumer demand.Unfortunately,such demand also results in a great deal of manure being generated,which threatens the environment if it is not properly managed.Concurrent developments in biotransformation of these wastes with the black soldier fly(BSF),Hermetia illucens(L.)(Diptera:Stratiomydiae),demonstrates such concerns can be abated,while also producing products(e.g.,protein,chitin,biodiesel,and fertilizer)of value.In this review,we analyzed the factors influencing black soldier fly larvae(BSFL)conversion processes,the role of microorganisms,and the mechanisms used by BSFL when converting livestock and poultry manure into these valuable products.The effects of BSFL conversion technology on reducing the hazards of such materials and their associated pathogens are reviewed,and the economics of livestock and poultry manure conversion by BSF larvae is discussed.

High Quality Insect for Livestock Manure Treatment-Hermetia illucens

The raising technology and nutritional value evaluation of Hermetia iUucens and its application in livestock manure treatment was reviewed, which lays a new theoretical basis for sustainable development of agriculture.

Utilization Survey of Livestock Manure Resources in Large-scale Farms of Yangzhou

Based on surveying the conditions of large -scale farms and commercial manure in the each county of Yangzhou city, the situations and problems for utilization of livestock manure resources were grasped. After an analysis of the potential value of livestock manure, the suggestion and strategy for utilization of livestock manure resources were proposed based on the actual conditions in Yangzhou city.

Bearing Capacity of Livestock and Poultry Breeding in Nanjing City Based on Planting-breeding Pattern

To assess the status of environmental beating capacity of livestock and poultry manure in Nanjing City, the environmental pollution warning value and environmental bearing potential of livestock and poultry manure in various districts of Nanjing were calculated according to livestock and poultry manure discharge coefticiem and manure content. The results showed that based on planting-breeding pattern, the livestock and poultry manure load in Nanjing City was 14.08 t/hm2 pig manure equivalent; the warning values of environmental bearing capacity of livestock and poultry breeding calculated by nitrogen and phosphor- us were 0.23 and 0.26, respectively, which were within the scope of environmental hearing capacity, with no threat to the environment. Under the premise of reasonable planing of livestock and poultry breeding and comprehensive utilization of manure, the environmental beating potential of livestock and poultry breed- ing in Nanjing City were 5. 667 3 million （nitrogen） and 11. 109 1 million （phosphorus） pigs equivalent, and there were nearly one third of bearing space more than the existing total breeding quantity.

Breakthrough of Carbon-Ash Recalcitrance in Hydrochar via Molten Carbonate:Engineering Mineral-Rich Biowaste Toward Sustainable Platform Carbon Materials

The function-led design of porous hydrochar from mineral-rich biowaste for environmental applications inevitably suffers from carbon-ash recalcitrance.However,a method to alter the original carbon skeleton with ash remains elusive and hinders the availability of hydrochar.Herein,we propose a facile strategy for breaking the rigid structure of carbon-ash coupled hydrochar using phase-tunable molten carbonates.A case system was designed in which livestock manure and NaHCO3 were used to prepare the activated hydrochar,and NH3 served as the target contaminant.Due to the redox effect,we found that organic fractions significantly advanced the melting temperature of Na2CO3 below 800℃.The Na species steadily broke the carbon-ash interaction as the thermal intensity increased and transformed inorganic constituents to facilitate ash dissolution,rebuilding the hydrochar skeleton with abundant hierarchical channels and active defect edges.The surface polarity and mesopore distribution collectively governed the five cycles NH3 adsorption attenuation process.Manure hydrochar delivered favorable potential for application with a maximum overall adsorption capacity of 100.49 mg·g^(-1).Integrated spectroscopic characterization and theoretical computations revealed that incorporating NH3 on the carbon surface could transfer electrons to chemisorbed oxygen,which promoted the oxidation of pyridine-N during adsorption.This work offers deep insight into the structure function correlation of hydrochar and inspires a more rational design of engineered hydrochar from high-ash biowaste.

Sources and Accumulation Risk of Heavy Metal in Major Animal Manure

Feed and corresponding manure samples were collected from 27 scale pig farms and 7 scale chicken farms in Jiaxing City, Zhejiang Province, and their heavy metal contents were analyzed. The weighted average values of Cr, Cu, Zn, Pb and As in pig feed were 4.6, 123.4,370.7, 0. 69 and 6.9 mg/kg, respectively. However, referred to Safe Use Specification of Feed Additives and MOA Announcement No. 1224, the exceeding standards rates of Cr, Cu, Zn, Pb and As in pig feed were 5.36%, 62.5%, 19.64%, 3.57% and 37.5%, respectively. The sequences of heavy metal content in pig feed successively were piglet 〉 growing pig 〉 big pig 〉 sow, but the exceeding standard rates of heavy metal in feed were big pig 〉 sow 〉 growing pig 〉 piglet, and the exceeding standard rate of big pig feed was more than 95%. The exceeding standard rates of Cu, Zn and As in chicken feed were 46.7%, 11.1% and 33.3% respectively. Based on Organic Fertilizer （ NY525 -2012 ） and Sludge Agricultural Pollution Control Standard （ GIM284-84）, Cu, Zn and As in pig manure and chicken manure exceeded the standard; the exceeding standard rates of pig manure were 71.9%, 78.9% and 42.1%, while that of chicken manure were 12.5%, 25.0% and 44.4%, respectively. The exceeding standard rates of Cu and Zn in piglet manure reached 100%. There were very significant positive correlations in Cu, Zn and As between pig feed and corresponding manure, or Hg, Cu and As between chicken feed and corresponding manure, and the correlation eoeffi 2 cients r were greater than 0.8. Besides, the correlation coefflclent r of Pb between pig feed and corresponding manure was above 0.6. Continuous and high intensity of livestock manure application significantly promoted the accumulation of heavy metal in farmland soil, but the effects on heavy metal accumulation in rice was not significant.

Current Situation and Countermeasures of Utilization of Crop Straw as Feed in Sichuan Province

Utilizing straw as feed and applying cattle and sheep manure fertilizer to the field plays an important role in solving the shortage of feed raw material resources,alleviating the conflict between human beings and livestock,and realizing the full utilization of straw as a resource and green and low-carbon circular development.We carried out an investigation on the feed utilization of crop straw in Sichuan Province,comprehensively grasped the crop straw resources and its utilization as feed in this province,deeply analyzed the existing problems,and put forward countermeasures and suggestions according to the actual situation in Sichuan,which plays an important role in accelerating the process of straw feed utilization,promoting green development,implementing the rural revitalization strategy,and building a beautiful Sichuan.

Spatiotemporal distribution,environmental risk and carbon emission reduction potential of livestock manure in Shaanxi Province,China

Shaanxi is a leading province in animal husbandry(AH)in China.However,the lack of provincial information on the characteristics and utilization potential of livestock manure(LM)hinders crucial management decisions.Therefore,we investigated the spatiotemporal distribution,availability and biogas potential of LM in Shaanxi,and examine the carbon emission reduction potential of AH.There has been a 1.26-fold increase in LM quantities in Shaanxi over the past 35 years,reaching 4635.6×10^(4)t by 2021.LM was mainly concentrated in northern Shaanxi and the eastern part of Hanzhong.Cattle and pig manure were the primary sources of LM,with the average LM land-load of 14.57 t·ha^(−1)in 2021.While the overall AH in Shaanxi has not exceeded the environmental capacity,the actual scales of AH in Ankang and Hanzhong have already surpassed the respective environmental capacities,posing a higher risk of N and P pollutions.In 2021,the estimated biogas energy potential of LM was 1.2×10^(11)MJ.From 2012 to 2021,the average carbon emission reduction potential in Shaanxi was 22%,with an average potential scale of 10%.The results of this research provide valuable data and policy recommendations for promoting the intensive use of LM and reducing carbon emissions in Shaanxi.

Investigation and analysis of the linkage mechanism and whole process cost of livestock manure organic fertilizer

In recent years,the utilization of manure resources for livestock and poultry farming has attracted a widespread attention,and manure resources utilization models suitable for different regional characteristics have formed gradually.Among them,the production of organic fertilizer from animal manure is a vital utilization method.However,there are still some problems such as high production costs,difficult sales,and the unwillingness of farmers to use organic fertilizers which have affected the breeding cycle and the sustainability of manure treatment in livestock and poultry breeding.This article selected 371 organic fertilizer plants,related farms and farmers in China,focusing on the main links of the entire process of livestock manure-organic fertilizer-farm application,and studied the mode of animal manure collection by organic fertilizer plants.The costs of organic fertilizer production and farmland application were discussed.Moreover,suggestions were made for the promotion and implementation of large-scale organic fertilizers to make good utilization of manure resources in livestock and poultry farming.

Environmental effects and risk control of antibiotic resistance genes in the organic solid waste aerobic composting system: A review

Antibiotic resistance genes(ARGs)have been diffusely detected in several kinds of organic solid waste,such as livestock manure,sludge,antibiotic fermentation residues,and food waste,thus attracting great attention.Aerobic composting,which is an effective,harmless treatment method for organic solid waste to promote recycling,has been identified to also aid in ARG reduction.However,the effect of composting in removing ARGs from organic solid waste has recently become controversial.Thus,this article summarizes and reviews the research on ARGs in relation to composting in the past 5 years.ARGs in organic solid waste could spread in different environmental media,including soil and the atmosphere,which could widen environmental risks.However,the conventional composting technology had limited effect on ARGs removal from organic solid waste.Improved composting processes,such as hyperthermophilic temperature composting,could effectively remove ARGs,and the HGT of ARGs and the microbial communities are identified as vital influencing factors.Currently,during the composting process,ARGs were mainly affected by three response pathways,(Ⅰ)“Microenvironment-ARGs”;(Ⅱ)“Microenvironment-microorganisms-ARGs”;(Ⅲ)“Microorganisms-horizontal gene transfer-ARGs”,respectively.Response pathway Ⅱ had been studied the most which was believed that microbial community was an important factor affecting ARGs.In response pathway Ⅲ,mainly believed that MGEs played an important role and paid less attention to eARGs.Further research on the role and impact of eARGs in ARGs may be considered in the future.It aims to provide support for further research on environmental risk control of ARGs in organic solid waste.

Effects of hydrothermal carbonization temperature on carbon retention,stability,and properties of animal manure-derived hydrochar

Hydrothermal carbonization of animal manure is being increasingly recognized as a green process for hydrochar production.Temperature obviously affects the properties of hydrochar especially with respect to carbon retention and stability.These properties determine the carbon sequestration potential of hydrochar but related researches are limited.In this study,chicken,dairy,and swine manures were collected and hydrothermal carbonized under different temperature conditions,aiming to study the fuel characteristics,carbon retention,and stability of hydrochar influenced by temperature.Results show that high temperature led to low yield and declined H/C,O/C,and volatile matter of hydrochar.While high temperature caused high fixed carbon,fuel ratio,and heating value of hydrochar,indicating that animal manure hydrochar can be adopted as an alternative of fuel.After hydrothermal carbonization,less than half of carbon from animal manure was retained in hydrochar:22.70%-46.71%for chicken manure,39.36%-49.72%for dairy manure,and 36.24%-64.21%for swine manure.The carbon retention decreased with the increase of temperature.Conversely,high temperature improved the aromatic and strengthened the resistance to thermal oxidation of hydrochar,which was evidenced by FTIR and TGA analysis.Moreover,the carbon sequestration capacity of animal manure hydrochar was less than a third of total carbon(originated from animal manure)and relatively low temperature(no more than 250℃)was beneficial to produce hydrochar for carbon sequestration.

NUMERICAL MODELING OF BIOMASS GASIFICATION USING COW DUNG AS FEEDSTOCK

In this study,a biomass gasification model was developed and simulated based on Gibbs free energy minimization by using software Aspen Plus.Two reactors,RYIELD and RGIBBS,were moslty used.The biomass feedstock used was cow dung.The model was validated.The composition,H_(2)/CO ratio and low heating value(LHV)of the resulting synthetic gas(also known as syngas)was estimated by changing the operating parameters of gasification temperatures,steam and biomass ratios and pressures.Simulation results showed that increased gasification temperature helped to elevate H_(2) and CO content and H_(2) peaked at 900℃.When steam increased as the gasification agent,H_(2) production increased.However,the steam/biomass(S/B)ratio negatively affected CO and CH4,resulting in lower LHV.The optimal S/B ratio was 1.5.An increase in pressure lead to a decrease in H_(2) and CO content,so the optimal pressure for gasification was 0.1 MPa.