Study of the influence of temperature and reducing agents on the chromium content in slag in the air atmosphere

Vladislav KURKA, Petr JONŠTA, Marek VINDYŠ, Roman NOGA, Ondřej KOTÁSEK, Marek DOBIÁŠ
MATERIAL AND METALLURGICAL RESEARCH Ltd., Pohraniční 693/31, 703 00 Ostrava-Vítkovice, Czech Republic; e-mail: vladislav.kurka@mmvyzkum.cz

The paper presents the results of laboratory experiments of the reduction of chromium and its oxides from slag using carbon and silicon reducing agents. The study of chromium reduction from molten slag to molten steel was carried out for slag originating from the production of stainless steel with an average elemental content of 0.16 wt. % C, 16.25 wt. % Cr, 5.00 wt. % Ni and 1.05 wt. % Mo. Based on the literature studies experiments on chromium reduction from slag with high Cr₂O₃ content (16 wt. %) were designed, implemented, described and subsequently evaluated. The reduction was carried out using a reducing agent of carbon in the form of anthracite and silicon in the form of ferroalloy FeSi. The atmospheric conditions and pressure were used for experiments. The temperature of the slag was raised by an oxy-fuel burner and the carbon and silicon reducing agents were applied on the surface of the molten steel. The experiments confirmed the possibility of reducing up to 62 % of chromium from the molten slag back into the stainless steel melt.

Keywords: Stainless steel, slag, chromium, carbon, silicon, ferrosilicon.

Effect of chemical additives (coagulants) on the nutritional quality of compost prepared from poultry litter

Adila BASHIR ^a, Mohammad NAFEES ^a, Nazish Huma KHAN ^b, Farooq AHMAD ^c
a University of Peshawar, Department of Environmental Sciences, Peshawar, Pakistan,
^b University of Swabi, Department of Environmental Sciences, Peshawar, Pakistan,
^c University of Malakand, Department of statistics, Swat, Pakistan,
e-mail: adilabashir786@gmail.com, nafees36@yahoo,com, humakhan876@gmail.com, farooq_ahmad@uop.edu.pk

This study was conducted to know about the nutritional quality of poultry litter amended with chemical coagulants after composting. For this purpose, chemical coagulants (i.e. Aluminum Sulphate and Aluminum Chloride, a dosage of 45g /chick) were applied in the selected poultry farms.  Three types of poultry litter (i.e. treated with Aluminum Sulfate, Aluminum Chloride and untreated waste/control) were collected for compost and characterized for different macro and micro nutrients. It was observed that pH, EC, organic carbons were decreased while the nitrogen content was increased in chemically treated composts. The percentage difference in  pH was -6.5%, -10.5% and -11.3%; -EC 6.1%, -19.3% and -15.6%; organic carbon -12.9%, -20% and -20%, while nitrogen was +24.6%, +28% and +25.2% for control compost, Al₂SO₄ treated litter compost and Al₂Cl₃ treated litter compost. Furthermore, the comparative analysis showed the sequence of high nutrition as control> control compost> Aluminum Chloride treated compost>Aluminum Sulfate treated compost. The recorded metal contents of control and composts were within the permissible limits set by USEPA and considered safe for agriculture. One-way anova among control and compost group showed significant (p =.000) effects while the interaction showed a non-significant difference (p =.744). However, the extensive and regular application of poultry litter may cause metal contamination. Hence, to ensure its benefits as a soil conditioner, it was recommended to implement management strategies such as chemical amendments of poultry litter, proper composting and regular monitoring of the poultry litter application into the soil.

Keywords: Aluminum Sulfate (Al₂SO₄); Aluminum Chloride (Al₂Cl₃); Amendment; Poultry Farms.

Retail Chains Under the Food Waste Spotlight: the Case Study Of the Czech Republic

Iveta Boskova, Marcela Kormanakova  
Institute of Agricultural Economics and Information, Manesova 75, 120 00 Praha 2, Czech Republic, e-mail: boskova.iveta@uzei.cz  

Retail is an intermediary between food producers and consumers and can influence other actors in the agri-food chain. The authors explored the volume of wasted food in the large food stores in the Czech Republic as well as the retail chains' strategies and barriers to reduce it. At the same time, the main reasons for food waste in Czech households were examined. Consumer-oriented retail chain activities were confronted with the reasons for household food wasting and whether a parallel could be found between certain retail and household activities was discussed. Despite the fact that the share of food waste compared to food quantity sold is rather small, the total annual volume of lost food is enormous. The retail chains indicated strategies focused on internal processes as well as toward external entities. The most frequent reason for food wasting mentioned by consumers is over-purchase. Only a negligible portion of them indicated that the reason is purchases made under pressure, such as discounts or child demands. One can consider whether consumers are really not un-pressured when shopping, or if retail marketing policies are so sophisticated that customers buy more than they need without perceiving it. Unfortunately, reducing promotions and discounts as a means of waste reduction was not mentioned by retail chain managers. For further progress, adjustments in legislation are recommended, as well as media education aimed at civic responsibility to increase consumer cooperation. 

Key words: retail chains; food waste; prevention strategies; consumers attitudes

Utilization of Solid Waste from Landfill Passive Zone to Treate Leachate Through A Combination of Leachate Recirculation and Bulking Agent

Wiharyanto OKTIAWAN^a, Ika Bagus PRIYAMBADA^a, Purwono PURWONO^b*
a Department of Environmental Engineering, Faculty of Engineering, Diponegoro University, Jl. Prof. Soedarto, SH, Tembalang, Semarang Indonesia, 50275,
e-mail: w_oktiawan@yahoo.com
^bCenter for Science and Technology, UIN Raden Mas Said Surakarta, Jl. Pandawa, Pucangan, Kartasura, Indonesia 57168
^* corresponding author e-mail: purwono.ga@gmail.com

Real evidence of the Municipal Solid Waste (MSW) decomposition process is the emergence of pollutants as leachate, which has a chemical composition that is difficult to degrade (recalcitrant compounds) and causes pollution of water bodies. On the other hand, waste from the passive zone landfill is not utilized at all. The aim of this study was to determine the effect of adding solid waste from landfill passive zone as bulking agent to treat fresh leachate with a combination of the recirculation process. MSW + bulking agent (70%: 30%, v/v) was recirculated using fresh leachate with a flow rate of 1 L/min for 30 days. Reactor without recirculation and bulking agent was used as control. The leachate quality was analyzed on days 0, 3th, 7th, 14th, and 30th, while the MSW composition was controlled after being left for 365 days. The outcome of the results obtained from the experiment showed that the addition of bulking agent + recirculation accelerated the increase in leachate pH and the increment of COD reduction. On day 30th, the lowest TDS level presented 63,813.8 mg/L, the conductivity was 111,457.5 µS/cm, and the ammonia showed 72.5 mg/L produced from R3 (MSW + bulking agent + recirculation). The addition of bulking agents from passive landfill zones can reduce COD, TDS, conductivity and ammonium. On the 365th day, the water content of MSW in R3 was 76.8%, pH value get 7.7, EC value presented 43.4 mS/cm and volatile solid achieved 94.99%. The same increase occurred in the total Nitrogen at R3 from 0.23% to 0.95%. Meanwhile, the levels of P-Total and K-Total did not change significantly.

Keywords: leachate; recirculation; solid waste; bulking agent; COD, landfill, MSW.

Assessment of the extracted coffee oil valorisation to biodiesel

Valentína KAFKOVÁ^a, Petra ONDREJÍČKOVÁ^b
aAssociation Energy 21, Trnavská cesta 1033, 920 41 Leopoldov, Slovak Republic,
e-mail: kafkova@enviengroup.eu
^bENVIRAL, a. s., Trnavská cesta, 920 41 Leopoldov, Slovak republic

Spent coffee grounds are generated after coffee brewing or instant soluble coffee production. An intensified consumption of coffee beverages leads into increased generation of spent coffee grounds. Mostly this biowaste is disposed into landfills or burned in incinerators. Spent coffee grounds have the potential to be transformed into value-added compounds with their subsequent recovery while having the positive impact on reduction of landfilled SCG amount at the same time. Spent coffee grounds contain on average 15% of oil, meaning that 15% of lipidic share can be potentially valorised into biodiesel. Aim of this work is to investigate suitability of oil extracted from spent coffee grounds (SCG oil) for biodiesel production, by comparison of analyses of SCG oil and oils commercially used for biodiesel production. Results of performed analyses have determined the need for SCG oil purification, or additional removal of unsaponifiable matter (almost 15% of oil content) present in the oil. In terms of fatty acid profile, SCG oil is suitable for biodiesel production, with the most abundant fatty acids being C18:2 (linoleic acid) and C16:0 (palmitic acid), together representing ~ 75% of the fatty acid composition (more than 60% of the SCG oil composition, respectively). Further studies will focus on the transformation of SCG oil to biodiesel. The aim of the project is to provide comprehensive insight into valorisation of spent coffee grounds into value-added compounds.

Keywords: coffee oil, spent coffee grounds, coffee waste, biodiesel, valorisation