Breakthrough Technologies for the Biorefining of Organic Solid and Liquid Wastes

有机固液废弃物包含大量能量、养分和水分,不应仅视其为废物。数十年来,人们一直对城市固体废物进行回收、堆制和燃烧,并从中提取能量和有价值的物质。污水的首要管理策略是治理和排放。随着技术的进步,通过新方法使利用固体废物和废水成为可能。考虑到废物特殊的化学、物理和生物性质,需要整合多种技术以使废物的能量和价值回收最大化。为此,生物炼制是完全利用废物中的能量和价值的一个合适的方法。研究证明,不可回收废弃物和生物固体可通过不同方法转化为可利用的热能、电能、燃料和化学品,并且液体废物或能帮助农作物和藻类的成长,为能量回收和食物生产提供不同的选择。本文针对有机固液废物提出新型生物炼制方案,这些废物来源于城市废料、食品和生物加工厂以及动物生产设施。四大新型突破性科技——真空辅助高温厌氧消化、扩展鱼菜共生系统、含油废物经甘油裂解制取生物柴油和微波辅助热化学转化,均可运用于生物炼制方案中,从而成功将废物转化,用以生产化学品、化肥、能量(沼气、合成气、生物柴油和生物油)、食物、饲料,得到干净的水并显著减少污染物的排放。

Specific Ion Effects on the Enzymatic Degradation of Polyester Films

Soil environment on earth contains a variety of ions,which are expected to play a vital role in the biodegradation of plastics discarded in the environment.In this work,poly(butyleneadipate-co-terephthalate)(PBAT)is employed as a model biodegradable plastic to study the specific ion effects on the enzymatic degradation of polyester plastics.The results show that the specific ion effects on the enzymatic degradation rate of the PBAT films and on the catalytic rate constant for the enzymatic hydrolysis of the ester bonds are strongly dependent on temperature and ionic strength.Both the enzymatic degradation rate and catalytic rate constant decrease following the trends Na^(+)>K^(+)>Ca^(2+)and Cl^(-)>SO_(4)^(2-)>NO_(3)^(-)for cations and anions,respectively,indicating that the ion-specific enzymatic degradation of the PBAT films is closely correlated with the specific ion effects on enzymatic hydrolysis of the ester bonds.Our study shows that the specific ion effects on the enzyme activity can be understood by taking into account the ion-specific cation-anion interaction,ionic dispersion force,salting-out effect and salting-in effect.This study of specific ion effects on the enzymatic hydrolysis of the ester bonds and the resultant enzymatic degradation of the PBAT films would offer us a new clue to develop new biodegradable,environmentally friendly synthetic plastics.

Life cycle assessment of pyrolysis process of Desmodesmus sp.

This paper described a comprehensive assessment of the pyrolysis process of 1 kg Desmodesmus sp.cultivated in BG11 medium at the optimum temperature by using life cycle assessment method.This assessment took 1 kg of Desmodesmus sp.as a functional unit,and chose energy efficiency analysis and potential environmental impact as assessment indices.The results showed that the energy conversion efficiency index of the pyrolysis process was above 1,which meant the pyrolysis process was beneficial.The primary impact of the pyrolysis process on the environment was eutrophication;which followed by photochemical ozone synthesis and acidification;and global warming impact was the last.The overall environmental impact during the whole life cycle was 1347.63 mPET2000.

Catalytic microwave assisted pyrolysis of aspen

The effect of catalysts on the microwave pyrolysis of aspen pellets was studied.A range of chlorides,nitrates and metal-oxides were added at 2%of the aspen mass(air dry aspen pellet weight basis).Chlorides in particular were found to favor liquid yield,especially the yield of water phase residue.Average liquid yield with added chlorides was 41%mass of the total biomass input,compared to 35%mass without catalyst.Metal-oxides were found to favor pyrolysis heavy oil,and thus total oil yield,since the yield of light oils seemed to be fairly constant.Nitrates were found to favor pyrolysis gas production.Pure light oils and light oils blended with diesel were found to be a potential diesel fuel substitute.

Isolation of microalgae with growth restriction and nutrient removal from alkaline wastewater

In order to isolate a well-tolerated microalgae strain and study its capability of wastewater treatment,a newly microalgae strain was isolated and identified from fresh water.The phylogenetic analysis indicates that this strain has a close relationship with Desmodesmus sp.,named as EJ 9-2.The effects of temperature,pH value and NaCl concentration on growth of Desmondesmus sp.were investigated;the capability of nutrient removal from alkaline wastewater was also observed.Desmodesmus sp.EJ 9-2 had a wide pH adaptation range(3-12)and could remove nitrogen,phosphorus and COD which might substantially decrease the cost of biofuel production.The research can provide evidence for outdoor large-scale cultivation of microalgae.

The current phosphate recycling situation in China and Germany:a comparative review

Phosphorus(P)is an indispensable element for organisms but the primary source of P-mineral phosphate resources-are non-renewable.Agricultural production has a high demand for fossil phosphate resources,but the resulting phosphate-rich residues are lack of management.This leads to rapid reserves depletion and severe phosphate pollution risks.One sustainable way is to reuse the phosphate dispersed in various residues such as sewage sludge and livestock manure.Diverse techniques have emerged to recover phosphate from wastes to close the phosphate cycle.While it is a global issue,the regional situations regarding potential phosphate scarcity and its management differ strongly.China is rich in phosphate resources,but over-exploitation has greatly increased the risk of phosphate rocks depletion,while in Germany the P resources depend on imports,but there is commitment to keep a balance between import and utilization.This had led to great differences in the way the two countries deal with the"re-use"of phosphate in waste.China is now in a transition phase from the simple terminal pollution control to"waste"reuse and nutrient resources recycling.One sign of this tendency is the mandatory garbage classification and preparation for further processing and recycling.This was first implemented in Shanghai in 2019,whereas Germany has been following the legal framework for waste management since the 19 th century.There are a series of laws to control the nutrient loss from municipal and agricultural activities,as for instance with sewage sludge ordinance and fertilizer legislation.Many of these laws have been newly revised recently.Sewage sludge cannot be directly utilized on farmland as organic fertilizer any more.Alternatively,phosphate and other nutrients should be recovered from sewage sludge.Advanced phosphate recovery technologies and related nutrient recycling schemes are proceeding.This review summarizes the current situation of phosphate-containing residues management and phosphate reuse in China and Germany.The state legislation and policies,which would affect the phosphate recycling concept are presented as well.As there are various kinds of phosphate-containing residues,different phosphate recovery technologies can be applied.Those technologies are discussed from their mechanism and suitability.

Manure nutrient application on a Chinese dairy farm with arable land:A case study based on Dutch experience of equilibrium fertilization

For a Chinese dairy farm with 2200 milking cows,the annual manure production and manure nutrients(nitrogen and phosphorus)were estimated.Gaseous nitrogen losses from cattle housing with scraped solid floors were based on on-farm measurements.Based on experiences from the Netherlands,nutrient levels in the solid and liquid fractions after slurry separation were estimated.On the basis of assumptions for nutrient losses during covered lagoon storage and land application of the liquid fraction,nitrogen and phosphorous fertilization rates were calculated for the 67 hm^(2)of agricultural land that receive the liquid fraction by gravity irrigation.The results show that the application rates of nitrogen and phosphorous significantly exceed the crop needs,which will probably result in losses to soil and water.In order to aim for a balance between nutrient application and crop needs and,as such,reduce environmental harm,the authors recommend to establish application standards for nitrogen and phosphorous on arable land in China and to formulate farm-specific Nutrient Management Plans.

Inventory analysis of carbon footprint on greenhouse gas emission of large-scale biogas plants

Inventory analysis of greenhouse gas emission for large-scale biogas plants using carbon footprint method still needs to be improved.Based on the life cycle theory,the application of carbon footprint on four large-scale biogas plants was analyzed in this paper,which comprehensively considered project progresses of civil engineering construction,operation and comprehensive utilization of residues and slurry.Also the greenhouse gas emissions during the construction and waste removal stages were analyzed and estimated.The carbon footprint of those plants was analyzed in different types and scales.The results showed that the larger scale plant will produce relatively lower carbon footprint.The greenhouse gas emission of energy production,utilization during the period of anaerobic digestion accounted for more than 96%of the entire life cycle emission.The proportion of greenhouse gas emissions on equipment,demolition recycling and transportation phases was smaller,which was less than 1.5%and should be simplified in calculation.The greenhouse gas emission of building materials production can be ignored.

Anaerobic digestion of heat treated sludge liquor by pilot scale mesophilic EGSB reactor

Biogas recovery from heat treated sludge liquor was tested by a 4 m^(3)mesophilic expanded granular sludge bed(EGSB)reactor within 206 days.Before pilot experiment,the heat pretreatment effects on hydrolysis and biogas production potential on three sludges from different wastewater plants were evaluated using bench test.One of these sludges was used in the subsequent pilot heat treatment and EGSB reactor.The biogas conversion potential of this sludge filtrate was 79%.Seeded with granular sludge,the EGSB reactor could be quickly activated and adapted to the new filtrate substrate.The EGSB influent COD was 20.0-35.0 g/L,and the effluent COD was lower than 10.0 g/L.The COD removal rate was 60%-70%at an organic loading rate(OLR)of 10.0 kg COD/(m^(3)·d).The fresh supernatant with low pH resulted in the high biogas production in EGSB.The effluent with high nitrogen and phosphor should be considered for further treatment.

A sol-gel transition induced by dilution

Shaped by multiple noncovalent interactions,the interwoven fibrous network consisting of several components(collagen,laminin and proteoglycans etc.)is a unique feature reserved by the natural extracellular matrix(ECM).Recently,great attention of scientists has been aroused to mimic ECM through constructing the synthetic supramolecular systems[1,2].

Liquefaction of corn stover using industrial biodiesel glycerol

Corn stover was liquefied using an industrial biodiesel glycerol as a liquefying agent at atmospheric pressure and low temperature.It was found that the liquefaction yield increased with increasing glycerol-to-corn stover ratios.Sulfuric acid,added as a catalyst,was found to improve liquefaction yield.The hydroxyl number,moisture content,acid number,pH value,viscosity,density,elemental composition,and higher heating value of the liquefied corn stover samples were determined.The liquefied corn stover showed a high hydroxyl number of 270-310 mg KOH/g.Fourier transform infrared spectroscopy(FTIR)results revealed the functional groups and confirmed the existence of the OH group in the liquefied corn stover,indicating that the liquefied corn stover is indeed a source of polyols and a potential chemical stock for the synthesis of polymers.

Patterns of dairy manure management in China

The dairy industry in China is rapidly developing,particularly in terms of the upscaling of dairy farms.However,nutrient-rich manure brings challenges to the sustainability of the dairy industry.This study investigated and reviewed the patterns of dairy manure management in China,and the results indicate that dairy manure could be used as an organic fertilizer because of its high organic nutrient content and low metal content.However,legislation prohibits the application of untreated(raw)dairy manure.An existing technology for handling animal slurry is the separation into a liquid and a solid manure fraction.The solid fraction can be used as compost and bedding materials,and it has limited environmental risk.However,the emissions from the storage of liquid manure need further attention.The cycle of manure production,collection,transportation,separation and storage can only be closed if the nutrients are eventually applied to grass and arable land according to crop needs.Therefore,distribution of knowledge on nutrient levels,crop needs and nutrient management plans,supported by legislation on maximum application standards,is needed.In this way,an environmentally friendly development of dairy manure management might be possible.

Processing and properties of rigid polyurethane foams based on bio-oils from microwave-assisted pyrolysis of corn stover

A new kind of rigid polyurethane(PU)foam was synthesized from the oil phase of bio-oils from microwave-assisted pyrolysis of corn stover.The recipes for the PU foams consisted of polyol-rich bio-oils,water as blowing agent,polyethylene glycol(PEG)as both polyol donor and plasticizer,diphenylmethane-4,4’-diisocyanate(polymeric MDI)as cross-linking agent,silicon-based surfactant,and tin-based catalyst.The mechanical properties of rigid foams were measured with universal testing machine(Instron4206).The effects of individual ingredients on the physical and mechanical properties of the foams were studied.It was found that water content,bio-oil content,and isocyanate dosage were important variables in making PU foams in terms of mechanical strength,density,and cellular structure Under optimal conditions,the compression strength of the prepared PU foams reached 1130 kPa with a density of 152.9 g/L.The results show that bio-oils are potential renewable polyol sources for making rigid PU foams.

Construction of Metallacycle-Linked Heteroarm Star Polymers via Orthogonal Post-Assembly Polymerization and Their Intriguing Self-Assembly into Large-Area and Regular Nanocubes

of main observation and conclusion In recent years,synthesis of hybrid heteroarm star polymer with precisely defined arms has evolved to be one of the most attractive topics within polymer chemistry.In this study,we present the successful synthesis of metallacycle-linked heteroarm star polymers(HASPs)composed of crystalline poly(e-caprolactone)(PCL)and polyacrylate(poly(N-isopropylacrylamide)(PNIPAM)segments via combination of ring-opening polymerization(ROP)and reversible addition-fragmentation chain transfer(RAFT)controlled radical polymerization.Firstly,a hexagonal metallacycle containing three hydroxy groups and three chain transfer agent moieties at the alternative vertexes was designed and synthesized based on the general principle of coordination-driven self-assembly.Subsequently,upon combination of two orthogonal post-assembly polymerizations,a new family of HASPs containing a well-defined hexagonal metallacycle with precisely controlled position of polymer arms was facilely prepared.Interestingly,the obtained HASPs could spontaneously self-assemble into large-area and regular cubic nanoparticles in tetrahydrofuran(THF)/methanol(MeOH)mixed solvents under specific conditions as confirmed by scanning electron microscopy(SEM)and atomic force microscopy(AFM).This study provides a simple route to the controllable preparation of HASPs,and opens up a new way for further study on self-assembly of different HASPs systems.