Separation Of Slurry Research Articles

Correction to “Study on the Hydrocyclonic Separation of Natural Gas Hydrate Slurries Combined with the Solution of Particles’ Settling Equation”

Correction to “Study on the Hydrocyclonic Separation of Natural Gas Hydrate Slurries Combined with the Solution of Particles’ Settling Equation”

The Quality of Dairy Cow Bedding and the Occurrence of Environmental Mastitis: Review

An excessive incidence of inflammation of the mammary glands of dairy cows has been observed in many dairy farms in the past, which has been demonstrably correlated with an increased incidence of microbial pathogens in livestock environments. The causes of mastitis can be infectious or non-infectious in nature, one of the main sources of this disease is litter material in the lager. The issue of mastitis has a significant impact on the economic value of dairy cows and therefore it is necessary to create effective measures that eliminate the appearance of pathogenic microorganisms. In this respect, litter material obtained by physical separation and thermal treatment of slurry may represent a suitable alternative ensuring inhibition of the development of dangerous bacteria while maintaining the comfort of dairy cows. Current evidence on the safety and benefits of such material is limited and data on effects on clinical and/or subclinical mastitis are insufficient. In this review, therefore, we would like to shed light on the onset of mastitis in dairy cows and point out possible procedures for treating slurry in practice.

Study on the matching rules and control mechanisms between flocculants and slurry settlement characteristics

In order to realise efficient, economic, low carbon and environmentally friendly slurry disposal, floc sedimentation velocity (S f ), supernatant volume (V s ), water content of bottom mud (W b ), supernatant turbidity (N s ) and pH value were determined by slurry sedimentation tests, specific resistance tests, and water quality analysis. Orthogonal tests were performed to analyze the matching rule and control mechanism between flocculants and the slurry settlement characteristics. The results show that polyaluminum chloride (PAC) and polyferric chloride (PFC) had a low dose and a fast sedimentation rate. The sedimentation effect of 20 ionic degree cationic polyacrylamide (CPAM-20) in organic flocculant is the best. Although flocculants can shorten the sedimentation time, excessive flocculants can also weaken the slurry separation effect. The sedimentation efficiency of organic flocculants is higher than that of inorganic flocculants, but it is easy to form foam on the supernatant surface. For the composite flocculants, the sensitivity sequence of S f , V s and W b is PAC>CPAM-20>PFC. PAC plays a controlling role in the sedimentation effect of the slurry.

Fates of nutrients, bacteria community, and antibiotic resistance genes during membrane separation of biogas slurry at industrial scale

The swine wastewater was rich in nutrients, microbes, and antibiotic resistance genes (ARGs), thus the discharge without treatment could inevitably pose numerous harms to environment. Multistep membrane separation has been developed as a promising strategy to achieve nutrient recovery and harmful contaminants removing. Here, an integrated membrane separation system including ultrafiltration and reverse osmosis was used to treat the biogas slurry produced from swine wastewater, and samples were gathered from different points. Then, a series of physicochemical parameters were analyzed, and 16S rRNA gene amplicon sequencing and real-time qPCR was used to research the bacteria communities and the abundance of ARGs in each sample, respectively. Results showed that the integrated membrane filtration could reject most of conventional pollutants, and the final permeate, which has extremely low levels of nutrients and metal elements, could be reused to wash the piggery or meet the Chinese national discharge standard. Moreover, the membrane filtration also could reduce 99.99 % of the detected ARGs, and the bacterial abundance and diversity in the final permeate significantly decreased compared with the feed biogas slurry. Redundancy analysis and network analysis indicated that the size exclusion and the adaptation to the different water quality were the common driving forces for the variation of bacterial community and ARGs during the membrane separation processes. In addition, our results also revealed the variety of putative pathogen and abundance of ARGs except for nutrients in the reverse osmosis concentrate, thus further disinfection procedures should be implemented before resource utilization of the concentrate.

Mechanism and Influence of Dispersants on the Action of Polymer Flocculants Used in Slurry Separation.

The application of polymer flocculants plays a pivotal role in the slurry separation process of shields, and the dispersant used for treating cutter mud cakes can significantly impact the effectiveness of polymer flocculants, potentially leading to reduced efficiency in slurry separation. Experiments were conducted to select appropriate flocculants and investigate the influence of dispersants on flocculant effectiveness, aiming to assess the effect of flocculants and explore the relationships and mechanisms governing their influence. Changes in the patterns of slurry flocculation were revealed in terms of flocculation-driven precipitation and vacuum-filtration effects. The purpose of this article is to provide a reference for the field application of polymer flocculants in the shield field. The conclusions are as follows. Inorganic flocculants containing 0.5% polyaluminum chloride (PAC) exhibit the most effective flocculation, demonstrating strong charge neutralization action. Organic flocculants containing 0.1% cationic polyacrylamides (CPAM) exhibit the most effective flocculation, demonstrating strong bridging and net capture effects. The dispersant sodium hexametaphosphate (SHMP) can significantly weaken the charge-neutralizing action of flocculants and slightly enhance bridging and net capture effects. SHMP can impede the flocculation of slurry with PAC. For CPAM, SHMP can enhance the flocculation of slurry at a low mass fraction (0.1% and 0.3%), while SHMP can significantly hinder flocculation at a high mass fraction (0.5% and 1%). A low mass fraction of SHMP reduced slurry viscosity to 246.3 mPa.s and enhanced vacuum filtration, while a high mass fraction of SHMP increased slurry viscosity to 667.2 mPa.s and hindered vacuum filtration. In conclusion, while dispersants reduce the effectiveness of inorganic flocculants at any mass fraction, a small number of dispersants enhances the performance of organic flocculants; thus, the organic flocculant CPAM is recommended for slurry separation.

Role of livestock-derived amendments in soil organic carbon stocks in forage crops

The use of organic amendments for forage production has been promoted in recent years due to the adoption of sustainable agricultural practices and the increasing cost of mineral fertilizers. Organic manures can contribute with an extra carbon to the soil to the potential addition of carbon stocks. This study aimed to measure the capacity of different organic amendments commonly available in livestock farms for forage fertilization to influence the rate of soil organic carbon (SOC) under future climate change conditions. For this purpose, on-farm processed exogenous organic matter (EOM) was analyzed for fiber and organic carbon mineralization to obtain the percentage of decomposable EOM and resistant EOM (DEOM and REOM, respectively). The RothC model was run in grasslands and forage maize under different scenarios considering specific DEOM and REOM values. The results showed that the degradability of amendments could influence SOC dynamics. The SOC of grasslands after 38 years of simulation differed by >30 % between compost and the liquid fraction of cattle slurry. Forage crops were simulated under the RCP8.5 scenario and fertilized with amendments at the recommended amounts of nitrogen for these crops. As a result, SOC stocks had a better response to organic fertilization in grassland, except under the application of the liquid fraction, with a decrease in SOC of 16 %. In cropland, only the solid fraction from mechanical separation of slurry and compost applications increased the SOC stock from 13 % to 26 % in the 2020–2090 period. Our study provides insights into how the degradability of EOM can affect simulations of the SOC stock rate over time.

Response surface optimization of chemical coagulation for solid–liquid separation of dairy manure slurry through Box–Behnken design with desirability function

Discharging livestock manure slurry without proper treatment causes various environmental and sociological problems. Chemical coagulation is a widely used and easily applicable method for treating such wastewater. However, the technique requires optimization to enhance coagulation efficiency while minimizing chemical usage. In this study, we propose an efficient, low-cost, and environmentally safe chemical coagulation method for solid–liquid separation of dairy manure slurry. Experiments were conducted in laboratory jar tests using dairy manure slurry to investigate the impact of coagulants, specifically polyaluminum chloride (PAC) and cationic polyacrylamide (CPAM), as well as pH, on the process of solid-liquid separation. Preliminary ranges of PAC, CPAM, and pH were estimated through single-factor experiments. Coagulation optimization and modeling were performed using the response surface methodology (RSM) with the Box-Behnken design (BBD), wherein the desired goal of each parameter was set to maximize solid–liquid separation efficiency while reducing chemical dosage to maintain residual aluminum (Al) concentrations below water quality standards. Numerical optimization predicted that the optimal dosages were 75 mg/L of PAC and 35 mg/L of CPAM at pH 7. Under these conditions, removal efficiencies of 99% for turbidity and 97% for chemical oxygen demand (COD) were achieved, with a minimal residual Al concentration of 0.045 mg/L. Positive zeta potential values in the treated water confirmed complete separation of negatively charged solids in the dairy manure slurry. The response values predicted by BBD aligned with the experimental results, and the analysis of variance (ANOVA) demonstrated the predictability and accuracy of the response models. Consequently, this study highlights the practical application of RSM with BBD in optimizing chemical coagulation using PAC and CPAM to achieve efficient solid–liquid separation in livestock wastewater while maintaining low residual Al concentrations.

Study on the Hydrocyclonic Separation of Natural Gas Hydrate Slurries Combined with the Solution of Particles’ Settling Equation

Study on the Hydrocyclonic Separation of Natural Gas Hydrate Slurries Combined with the Solution of Particles’ Settling Equation

Effectiveness of mechanical separation for reducing ammonia loss from field-applied slurry: Assessment through literature review and model calculations

To assess solid-liquid separation as a technology to reduce ammonia (NH3) emission from storage and field application of animal slurry, it is necessary to consider a possible higher NH3 loss from the solid fraction after application than from raw slurry, as well as losses during storage. A literature review was conducted, and a case study was developed for Denmark, including cattle slurry, pig slurry, and biogas digestate applied by trailing hose, trailing shoe, or open slot injection at five different periods of the year. Standard storage emission factors were used and emission factors after field application were estimated using the ALFAM2 model with input data for dry matter (DM), pH, total ammoniacal nitrogen (TAN), and separation efficiency all from the literature compilation. In general, a clear reduction in the emission factors after application of the liquid fraction was found relative to application of raw slurry in the literature data. Case study results provide some evidence that separation of cattle slurry or digestate, followed by storage and subsequent application by trailing hose or trailing shoe of the liquid fraction and broadcast application of the solid fraction reduces overall NH3 loss, with a higher reduction when the solid fraction is incorporated by plowing after 4 h. This effect was not present for pig slurry. For all slurry types when the raw slurry and liquid fraction is applied by open slot injection, the overall reduction in emission due to separation is not present or even negative.

Study on structure optimization and applicability of hydrocyclone in natural gas hydrate exploitation

With the development of economy and industry, the consumption of fossil energy is gradually increasing. Currently, natural gas hydrates (NGH) are considered to be an ideal alternative energy due to its large reserve and high energy density. However, the separation of hydrate slurry is a critical step in the exploitation of NGH. In this study, the optimization of the structural parameters based on the conventional three-phase hydrocyclone was carried out using numerical simulation and orthogonal design. At the same time, the separation efficiency criterion E was defined to evaluate the separation efficiency by calculating the sum of the discharge efficiency of water and gas. Analysis of the effect of individual structural factors on the flow field distribution characteristics inside the hydrocyclone using the single factor analysis method. The results showed that: with the combination of structural parameters of s was 2 mm2 × 12 mm2, dz was 28 mm, h was 20 mm, and li was 28 mm, the maximum E of the three-phase hydrocyclone was 1.46. The effect significance of each structural parameter on the separation efficiency from the highest to the lowest was the s, dz, h, and li. In the single-factor analysis, when the s was 2 mm2 × 12 mm2, the tangential velocity, axial velocity, and CH4 volume fraction in the flow field reached the maximum of 13.65 m/s, 4.35 m/s, and 12.4%, respectively. But the minimum water phase volume fraction was 69.9% under this structural parameter condition. When the dz was 36 mm, the maximum decrease value of axial velocity in the flow field was 3.57 m/s, the maximum CH4 volume fraction was 12.4%, and the water volume fraction reached a minimum of 66.3%. The li and the h only had significant effects on the axial velocity and the water volume fraction, respectively. The axial velocity reached a maximum of 4.75 m/s when the li was 32 mm, and the water phase volume fraction reached a maximum of 77.9% when the h was 10 mm. The study of the structural parameters and flow field characteristics of this three-phase hydrocyclone applicable to the solid fluidization exploitation of NGH provides some guidance and suggestions for the separation of hydrate slurry after solid fluidization exploitation of NGH.

PCDD/Fs and heavy metals in the vicinity of landfill used for MSWI fly ash disposal: Pollutant distribution and environmental impact assessment

This study focused on the syngenetic control of polychlorinated-ρ-dibenzodioxins and dibenzofurans (PCDD/Fs) and heavy metals by field stabilization/solidification (S/S) treatment for municipal solid waste incineration fly ash (MSWIFA) and multi-step leachate treatment. Modified European Community Bureau of Reference (BCR) speciation analysis and risk assessment code (RAC) revealed the medium environment risk of Cd and Mn, indicating the necessity of S/S treatment for MSWIFA. S/S treatment significantly declined the mass/toxic concentrations of PCDD/Fs (i.e., from 7.21 to 4.25 μg/kg; from 0.32 to 0.20 μg I-TEQ/kg) and heavy metals in MSWIFA due to chemical fixation and dilution effect. The S/S mechanism of sodium dimethyldithiocarbamate (SDD) and cement was decreasing heavy metals in the mild acid-soluble fraction to reduce their mobility and bioavailability. Oxidation treatment of leachate reduced the PCDD/F concentration from 49.10 to 28.71 pg/L (i.e., from 1.60 to 0.98 pg I-TEQ/L) by suspension absorption or NaClO oxidation decomposition, whereas a so-called “memory effect” phenomena in the subsequent procedures (adsorption, press filtration, flocculating settling, slurry separation, and carbon filtration) increased it back to 38.60 pg/L (1.66 pg I-TEQ/L). Moreover, the multi-step leachate treatment also effectively reduced the concentrations of heavy metals to 1–4 orders of magnitude lower than the national emission standards. Furthermore, the PCDD/Fs and heavy metals in other multiple media (soil, landfill leachate, groundwater, and river water) and their spatial distribution characteristics site were also investigated. No evidence showed any influence of the landfill on the surrounding liquid media. The slightly higher concentration of PCDD/Fs in the soil samples was ascribed to other waste management processes (transportation and unloading) or other local source (hazardous incineration plant). Therefore, proper management of landfills and leachate has a negligible effect on the surrounding environment.

Preparation, characterization, and evaluation of suspension stabilizer for low‐density cement slurry for cementing

AbstractA low‐density cement slurry system is commonly used in low‐pressure and leakage‐prone cementing. However, the suspension stability of the system is more difficult to control because of the addition of lightning material. Especially under the condition of large temperature differences, the relative motion between solid particles with large density differences increases, which will aggravate the instability of the slurry and affect the cementing quality. Therefore, to effectively control the suspension stability of the low‐density cementing slurry system, the suspension stabilizer PAND was synthesized by free radical solution polymerization withN‐vinyl caprolactam (NVCL); 2‐acrylamide‐2‐methyl propane sulfonic acid (AMPS),N, N‐dimethyl acrylamide (DMAA) as monomers. The effect of PAND on the stability of low‐density cement slurry under a large temperature difference (40 ~ 120°C) was evaluated. The results showed that under 40 ~ 120°C, adding 0.8% PAND can control the water separation of the cement slurry to 0; the density difference between the upper and lower parts of the cement stone column after curing is less than 0.01 g/cm3. The mechanical properties of cement stone are improved, which shows that it has a good suspension stability effect on low‐density cement slurry systems. The analysis of UV spectroscopy and scanning electron microscopy showed that PAND formed an intermolecular hydrophobic association network structure with the increase in temperature, which could maintain the viscosity of the solution system, thus playing an influential suspension stability role.

Effects of the Addition of Different Additives before Mechanical Separation of Pig Slurry on Composition and Gaseous Emissions

The treatment of animal slurry is used to improve management on a farm scale. The aim of this laboratory study was to assess the effects of the addition of the additives biochar, alum and clinoptilolite before the mechanical separation of whole pig slurry (WS) on the characteristics and emission of NH3, N2O, CO2 and CH4 from solid (SF) and liquid fractions (LF). The additives were mixed with WS (5% w/w), followed by separation, in a total of 12 treatments with 3 replicates, including the controls and WS with additives. Gaseous emissions were measured for 30 d by a photoacoustic multigas monitor, and initial characteristics of the slurries were assessed. The results indicated that the separation of the WS modified the initial physicochemical characteristics and increased the GWP emissions of the SF and LF, but not the NH3 losses. However, the addition of additives before separation increased the nutrient value and reduced the GWP emissions from the SF and LF. Additionally, just the additive alum was effective in the reduction of E. coli. The additives led to significant reductions in NH3 and N2O emissions, with higher reductions in NH3 losses for alum (51% for NH3) and similar N2O losses for all additives (70% for N2O) observed, whereas the CO2 and CH4 emissions were reduced by biochar (25% for CO2 and 50% for CH4) and alum (33% for CO2 and 30% for CH4) but not by clinoptilolite. Although the additives had a positive effect on slurry management, it can be concluded that the addition of alum before mechanical separation has the potential to be the best mitigation measure because it improves the nutrient content and sanitation and decreases gaseous losses from slurry management.

Effects of thermal modification on the separation of clay-containing waste slurries

This paper summarizes the results of studies on the use of thermal modification in the separation of slurries of clay-containing ores. It is currently vital to minimize the environmental footprint of tailings storage facilities of mining and processing enterprises and municipal waste landfills handling liquid wastes and to ensure their respective sanitary and epidemiological safety. The main liquid waste management problems are due to high process water consumption, high energy costs for dewatering and drying of concentrates, caking and congelation of concentrates, complexity and environmental hazards of storing wet waste (tailings), unsuitable for use as mine backfill material, as well as the use of inefficient TSF liner systems with potential soil and effluent contamination risks. This article considers the properties of clay-containing slurries, coal tailings, and halitic potash flotation tailings. It is shown that heat treatment improves waste slurry separation. For dry kaolin separation tailings, heat treatment at 200–400 °C significantly reduces tailings plasticity and fluidity, weakening soil interparticle cohesion and facilitating larger internal friction angles of the particles. The resulting data is used to analyze the potential applications of clay-containing ore processing wastes as a replacement for cement and lime in soil stabilization, land improvement, and mine reclamation, or as components in liner systems of municipal solid waste landfills.This study was carried out under the grant issued by the Russian Science Foundation (project No. 19-79-10114).

Experimental Study and Performance Enhancement of Rotary Drum Filter

In the Chemical Industry lot of Filters are frequently used for slurry separation that involves the separation of solid-liquid phase for continuous flow operations. One of the oldest and yet effective devices used still is the Rotary Drum Filter which can be called the workhorse of the chemical process industry. In this paper, we have discussed various parameters for enhancing the performance of rotary drum filters which include various physical well as chemical properties. My main objective was concerned with changing the various parameters like reducing the moisture content, the agitation speed, the cloth used for filtration, ph., slurry age, viscosity, cycle time, pressure drop, temperature involved which will not affect the cost of the process making it economically beneficial and handling can be done easily.

How does coal interact with organic groups in an aqueous solution?

Interactions between coal matrix and organics are vital for adsorption [1], surfactant adsorption on lignite [2-5], and solid–liquid separation of coal slurry [6-10]. Herein, for studying the interaction between hydrophobic surface (coal surface) and small molecules (organics), we measured interactions between organics [nitro and phenyl, pyridine, phenyl, alkyl chain (hexyl) or cycloalkyl (hexyl)] and the coal matrix (liptinite or inertinite) using atomic force microscopy. The strength of interaction followed the order: nitro and phenyl > pyridine > phenyl > alkyl chain (hexyl) > cycloalkyl (hexyl), and liptinite > inertinite. The liptinite has a greater hydrophobicity than inertinite, the greater the attraction force. The lignite surface and coal slurry were modified in an aqueous solution using five surfactants (dodecyl trimethyl ammonium chloride, DTAC; hexadecyl trimethyl ammonium chloride, CTAC; octadecyl trimethyl ammonium chloride, STAC; hexadecyl dimethyl benzyl ammonium chloride, HDBAC; and cetyl pyridine chloride, CPC). Subsequently, the moisture adsorption on treated lignite coal surface and the sedimentation of the treated tails was compared to characterize hydrophobic modifications which showed the order of CTAC > HDBAC > DTAC > CPC > STAC. Thus, the interaction between coal surface and organics needs to consider two rules: 1) The desolvation or the hydrophobic property of the coal surface; 2) The VDW force of the organics. The nature of the difference between rules No. 1 and 2 is that with the size of hydrophobic molecules increased to a surface, the H-bond structure between water molecules in the around would change a lot, which formats great hydrophobic property or desolvation. SynopsisInteraction between organic reagents and coal reveals the mechanism of restraining moisture reabsorption of lignite and solid–liquid separation of coal slurry by organics.

Experimental Study on the Influence of Borehole Angles on Fracture Grouting in Limestone Aquifers

Grouting is an effective method to ensure mining safety by reconstructing confined aquifers. However, the effect of grouting on deep‐buried aquifers is difficult to evaluate. Therefore, the experimental means in this paper are used to study the fracture grouting effect under the influence of borehole angles. A special device composed of boreholes and fractures is designed to study the whole process of grouting in limestone fractures. Four factors are tested in the experiment, including penetration distance, water separation, slurry stone body, and sealing effect. The results show that the slurry deposition can be divided into two stages, including the initial diffusion and the second gravity deposition. The water separation of mixed slurry is an important factor affecting the grouting effect. The slurry stone body formed through deposition is the key area for blocking water, and the borehole angles are the key to ensure the second gravity deposition. For a horizontal borehole, it is difficult to completely fill the space of fractures only by deposition and a certain angle is essential to achieve the second deposition. When the filling area of the fracture section is more than 90%, the flow characteristic of the fractures after grouting is closer to the equal percentage. When the filling area is less than 90%, the flow characteristics are approximately linear. At last, the data monitored in field grouting engineering are analyzed based on the grouting mechanism obtained from the experiment and the final consolidating form of slurry in a single fracture is described. The research is helpful for the optimization of grouting technology in the fractured aquifers under coal seams before mining.

Preface

ICESE 2021 was successfully held in a virtual conference mode between September 10 and 13, 2021. It was a scientific and engineering success. This conference was originally set to be hosted and held offline in Vienna, Austria. Due to the worldwide spread of Covid-19, the pandemic situation in various countries was complicated, and the entry-exit management of the Austrian government was strict. Considering the safety of the participants and to facilitate the input from more authors in the meeting while achieving a professional communication effect, the conference committee finally decided to hold the 11th International Conference on Environmental Science and Engineering (ICESE 2021) as a virtual conference which is organized by Univercity of Leuven Belgium.The primary goal of the conference is to promote research and developmental activities in Environmental Science and Engineering. A secondary aim is to promote scientific information interchange between researchers, developers, engineers, students, and practitioners working in many different countries. The conference will be held every year to make it an ideal platform for people to share views and experiences in Environmental Science and Engineering, and related areas.All sessions in this virtual conference were presented by Zoom. Many researchers, engineers, academics as well as industrial professionals from all over the world have presented their research results and development activities. Keynote speakers were allocated 40 minutes to deliver their speeches and 5 minutes for discussion. In the oral sessions, each author had 15 minutes for presentation and 5 minutes for questions and answers. During the question time, the author could use the “Raise Hand” function or “chat” function to ask questions. The ICESE 2021 Conference Chair, Prof. Jan Baeyens of both the Beijing University of Chemical Technology (China) and the KULeuven (Leuven, Belgium), made the Opening Remarks and delivered his keynote lecture on “Solid-liquid separation of particulate slurries”. Additional keynote speeches were delivered by both Prof. Lise Appels from KU Leuven, Belgium concerning “The anaerobic digestion as a key technology in a sustainable economy: current achievements and challenges” and by Prof. Soteris Kalogirou from Cyprus University of Technology (Cyprus) entitled “Status of Renewable Energy Systems in the World” All the three keynote speakers focused on the latest information and most innovative developments in their respective expertise areas on environmental science and engineering. For the oral conference papers, 6 parallel sub-sessions were held with various interesting topics as follows: (i) Ecosystems and Sustainable Development; (ii) Water Resource Management and Wastewater Treatment; (iii) Solid Waste Control and Energy Technology (I); (iv) Solid Waste Control and Energy Technology (II); (v) Air Pollution Control and Environmental Monitoring, and (vi) Human Health and Society.The ICESE 2021 proceedings are a compilation of the peer-reviewed and accepted papers and represent an interesting outcome of the conference where various topics were dealt with in different following main areas: (i) Global environmental change and ecosystems management, (ii) Integrated ecosystems management, (iii) Environmental restoration and ecological engineering, (iv) Habitat reconstruction, (v) Biodiversity conservation, (vi) Health and the Environment, among others.Finally, it is appropriate that we record our thanks to our organizing committees and reviewers for their work in securing a substantial input of papers. We are also indebted to those who served as Keynote Speakers, Conference Chairmen and Session Chairmen. Without their support, the conference could not have been as successful as it was. We also acknowledge the authors who have contributed to this volume, without whose expert inputs, this compilation of proceedings would not have been possible. We would like to thank all the conference participants for their support to ICESE 2021.Prof. Jan BaeyensBeijing University of Chemical Technology, ChinaKULeuven, BelgiumNovember 18, 2021

Use of Clay-Containing Tailings in Geopolymer Production

This paper stresses the enormous contribution made by L. A. Vaysberg (1944–2020), Doctor of Technical Sciences, professor, academician of the Russian Academy of Sciences, research supervisor at Mekhanobr-Tekhnika and Russia’s lead expert in mineral and man-made materials processing and mechanical engineering for the mining industry, to the design, engineering and operation of vibration machines that are used in mining, construction and recycling industries. Under Vaysberg’s leadership, Mekhanobr-Tekhnika realized a number of complex innovation projects aimed at developing and implementing on a large scale energy- and resource-saving technologies and equipment for mining, metallurgy and construction applications, as well as for the recycling industry that deals with the processing of various materials, including industrial and household waste. Today, the equipment produced by company is also used by the construction industry and for revamping of crushing, screening, asphalt and concrete production sites and other industries. This paper examines the effect of thermochemical modification on the separation of clay-containing ore slurries. Such sites as tailings ponds and landfills, which carry liquid phase, should minimize their environmental impact and ensure health safety. One of the possible ways to dispose of tailings is to utilize them as pozzolanic additives for cements (a mineral additive capable of bonding Ca(OH)2 into stable hydrates) and as a raw material for producing geopolymers. The authors look at the effect of various parameters on the way geopolymers form and on their properties. It was found that the process of thermochemical modification makes it possible to utilize the tailings of clay-containing ores as a raw material in geopolymer production. This research was funded through a grant by the Russian Science Foundation (Project No. 18-17-00169).

Phosphorus Flows, Surpluses, and N/P Agronomic Balancing When Using Manure from Pig and Poultry Farms

The pig and poultry industries continue to grow across the world and together they provide the majority of meat consumed. The European Union (EU) in particular has the highest global relative meat production by monogastrics (i.e., pig and poultry). The fate of phosphorus (P) in pig and poultry farming was studied, accounting for P content in feed, animals, manure, soil, and runoff. P input from manure, and P offtake in crops receiving manure, were plotted against each other to arrive at “safe” P loading rates, in order to minimize soil P surpluses along the lines of the EU Nitrogen Expert Panel in their work with nitrogen (N). However, it was observed that it is the N/P ratio and the background soil P levels that determine whether a certain manure will end up producing surplus levels of soil P. Critical N/P weight ratios were derived over different crop P offtake rates when applying stored manure to croplands. At spreading rates of 170 and 250 kgN/ha/year and a crop P offtake of 15 or 30 kgP/ha/year, stored pig and chicken manure result in soil P surpluses. An important factor in determining effective N/P ratios is the plant availability of N in stored manure, which runs at around 47%, estimated from previously published results. The minimization of N losses to the atmosphere and to groundwater in housing, storage, and spreading of manure has a major impact on the N/P weight ratio of the manure that ends up on fields. In most cases, half of the ex-animal N content has been lost in stored or degraded manure, with N/P weight ratios running at two and less. Following only the EU Nitrates Directive, which allows for a maximum of 170 kgN/ha/year in NVZs (Nitrate Vulnerable Zones), will often result in soil P surpluses leading to runoff losses to adjacent water bodies. Therefore, for the pig and poultry industries to continue thriving, measures are required to better manage manure, including improved storage and spreading techniques, acidification, separation, struvite extraction and ammonia stripping of pig slurry, and drying and pelleting of poultry litter. This way, excess manure and derived biofertilizers from animal farms can find their way back into the commercial market, instead of ending up as legacy P in watersheds and coastal zones.