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The rice-wheat cropping system (RWCS) provides the world's population with staple foods, and it is crucial to maintain global food demand and security. Food systems are a complex ecosystem and sustain many feedback mechanisms. Crop residue management is one of those feedback mechanisms that was assessed under conservation agriculture, and a decomposition study was analyzed for the rice-wheat cropping system using rice, wheat, and maize crop residue for decomposition rate and nutrients release under agricultural practices (zero till, raised beds). Different zero tillage techniques in Samastipur demonstrated an accelerated decomposition trend, which was especially noticeable in the straw from wheat and rice. At the same time, permanent bed systems showed a relatively larger residue mass, especially in the case of wheat and maize straw. Permanent bed systems (wheat-maize system), particularly those using wheat straw, held the largest amounts of residue mass when the total residue mass throughout the sites was taken into account. Samastipur showed higher nutrient release for all the rice residue in wheat, rice residue in maize, and wheat residue in rice except maize residue in rice as compared to the Karnal sites. Decomposition kinetics, modeled via a first-order exponential decay function, showed high correlations (R2: 0.941 to 0.996) across treatment methods. The research underscores the significant effect of agroecological factors on residue decomposition and nutrient release, irrespective of residue type, highlighting the importance of tailored residue management practices for enhanced nutrient cycling and sustainability. These findings contribute to the optimization of residue management strategies in RWCS, promoting sustainable agriculture practices in the face of climate change and increasing food security demands. [ABSTRACT FROM AUTHOR]

The rice-wheat cropping system (RWCS) provides the world’s population with staple foods, and it is crucial to maintain global food demand and security. Food systems are a complex ecosystem and sustain many feedback mechanisms. Crop residue management is one of those feedback mechanisms that was assessed under conservation agriculture, and a decomposition study was analyzed for the rice-wheat cropping system using rice, wheat, and maize crop residue for decomposition rate and nutrients release under agricultural practices (zero till, raised beds). Different zero tillage techniques in Samastipur demonstrated an accelerated decomposition trend, which was especially noticeable in the straw from wheat and rice. At the same time, permanent bed systems showed a relatively larger residue mass, especially in the case of wheat and maize straw. Permanent bed systems (wheat-maize system), particularly those using wheat straw, held the largest amounts of residue mass when the total residue mass throughout the sites was taken into account. Samastipur showed higher nutrient release for all the rice residue in wheat, rice residue in maize, and wheat residue in rice except maize residue in rice as compared to the Karnal sites. Decomposition kinetics, modeled via a first-order exponential decay function, showed high correlations (R2: 0.941 to 0.996) across treatment methods. The research underscores the significant effect of agroecological factors on residue decomposition and nutrient release, irrespective of residue type, highlighting the importance of tailored residue management practices for enhanced nutrient cycling and sustainability. These findings contribute to the optimization of residue management strategies in RWCS, promoting sustainable agriculture practices in the face of climate change and increasing food security demands.

The rice-wheat system in the Indo-Gangetic Plain, often termed the ‘food basket’ of South Asia, has witnessed a concerning trend in its potassium balance over the past few decades. This negative trend stems from intensive and exhaustive agricultural practices, leading to 79% of the soil in the region falling into the low to medium potassium available category. Consequently, there has been a decline in soils with high potassium availability. Despite misconceptions about soil potassium sufficiency, abundant crop responses to potassium fertilization in alluvial soils, like those in the Indo-Gangetic Plain, have been observed. However, the current negative potassium balance exceeds acceptable levels, posing a significant threat to system sustainability. Soil deficient in potassium fails to yield optimal outputs without external potassium inputs. Thus, maintaining adequate potassium levels within the rice-wheat system is imperative for sustaining agricultural productivity, preserving soil health, ensuring food security, and mitigating associated environmental impacts. To address these challenges, this review provides a comprehensive understanding of the current nutrient balance, existing fertilizer application rates and methods, and various strategies to optimize potassium mining. These strategies include balanced fertilizer usage, crop residue recycling, minimizing potassium leaching losses, employing customized fertilizers and potassium-solubilizing microbes, establishing a national soil data repository, and implementing policy interventions. By synchronizing potassium application with crop requirements, these strategies aim to enhance potassium use efficiency and maximize return on investment, ensuring the long-term sustainability of the rice-wheat system in the Indo-Gangetic Plains.

Super-hot acid leach residue is generated during zinc production in the roasting–leaching–electrowinning route, where both primary and secondary resources are used as feed material. This residue may contain valuable metals, such as lead, zinc, and iron, as well as precious metals, such as gold and silver. Four materials, namely super-hot acid leach residue, a residue formed when super-hot acid leach residue is selectively leached for lead with triethylenetetramine, as well as flotation concentrate, and flotation tailings formed in a selective silver flotation process with super-hot acid leach residue as the feed material were characterized to obtain a deeper understanding of possible further metal extraction. These four materials were characterized for chemical composition, mineralogy, and mineral distribution via chemical analyses, X-ray diffraction, and energy-dispersive scanning electron microscopy, respectively. The scanning electron microscope images showed that the materials have large variations in particle size distribution and composition. The results showed that the main lead phase in super-hot acid leach residue is lead sulfate, whereas it is mostly converted to lead sulfide during the selective lead leaching of the super-hot acid leach residue. The remaining lead sulfate is found in a solid solution with barium sulfate. Extracting lead from super-hot acid leach residue via triethylenetetramine leaching resulted in increased concentrations of gold and silver by 41% and 42%, respectively. The identified silver phases in super-hot acid leach residue may correspond to silver sulfide, silver chloride, and elementary silver, where silver sulfide was the most commonly occurring silver phase. After leaching this selectively for lead with triethylenetetramine, similar silver phases were identified, but silver sulfide and silver chloride occurred to a similar extent. Additionally, silver copper sulfide was detected. The presence of different silver phases might pose a challenge to reaching high silver recovery during leaching as the optimum leaching conditions differ somewhat. Furthermore, elemental sulfur, with a tendency to coat gold and silver particle surfaces, which is indicated to be present in all materials except the silver flotation tailings, may hinder metal extraction. [ABSTRACT FROM AUTHOR]

Super-hot acid leach residue is generated during zinc production in the roasting–leaching–electrowinning route, where both primary and secondary resources are used as feed material. This residue may contain valuable metals, such as lead, zinc, and iron, as well as precious metals, such as gold and silver. Four materials, namely super-hot acid leach residue, a residue formed when super-hot acid leach residue is selectively leached for lead with triethylenetetramine, as well as flotation concentrate, and flotation tailings formed in a selective silver flotation process with super-hot acid leach residue as the feed material were characterized to obtain a deeper understanding of possible further metal extraction. These four materials were characterized for chemical composition, mineralogy, and mineral distribution via chemical analyses, X-ray diffraction, and energy-dispersive scanning electron microscopy, respectively. The scanning electron microscope images showed that the materials have large variations in particle size distribution and composition. The results showed that the main lead phase in super-hot acid leach residue is lead sulfate, whereas it is mostly converted to lead sulfide during the selective lead leaching of the super-hot acid leach residue. The remaining lead sulfate is found in a solid solution with barium sulfate. Extracting lead from super-hot acid leach residue via triethylenetetramine leaching resulted in increased concentrations of gold and silver by 41% and 42%, respectively. The identified silver phases in super-hot acid leach residue may correspond to silver sulfide, silver chloride, and elementary silver, where silver sulfide was the most commonly occurring silver phase. After leaching this selectively for lead with triethylenetetramine, similar silver phases were identified, but silver sulfide and silver chloride occurred to a similar extent. Additionally, silver copper sulfide was detected. The presence of different silver phases might pose a challenge to reaching high silver recovery during leaching as the optimum leaching conditions differ somewhat. Furthermore, elemental sulfur, with a tendency to coat gold and silver particle surfaces, which is indicated to be present in all materials except the silver flotation tailings, may hinder metal extraction.

IntroductionOrganic farming is a promising solution for mitigating environmental burdens related to input-intensive agricultural practices. The major challenge in organic agriculture is the non-availability of large quantities of organic inputs required for crop nutrition and sustaining soil health, which can be resolved by efficient recycling of the available on- and off-farm resources and the integration of the components as per the specific locations.MethodsAn integrated organic farming system (IOFS) model comprising agricultural and horticultural crops, rainwater harvesting units, livestock components, and provisions for nutrient recycling was developed and disseminated in the adopted organic villages Mynsain, Pynthor, and Umden Umbathiang in the Ri-Bhoi District, Meghalaya, India, to improve the income and livelihood of farmers. Harvested rainwater in farm ponds and Jalkunds was used for live-saving irrigation in the winter months and diversified homestead farming activities, such as growing high-value crops and rearing cattle, pigs, and poultry.ResultsMaize, french bean, potato, ginger, tomato, carrot, and chili yields in the IOFS model increased by 20%−30%, 40%−45%, 25%−30%, 33%−40%, 45%−50%, 37%−50%, and 27%−30%, respectively, compared with traditional practices. Some farmers produced vermicompost in vermibeds (made of high-density polyethylene) and cement brick chambers, generating 0.4−1.25 tons per annum. Two individual farmers, Mr. Jrill Makroh and Mrs. Skola Kurbah obtained net returns (without premium price) of Rs. 46,695 ± 418 and Rs. 31,102 ± 501 from their respective 0.27- and 0.21-ha IOFS models, which is equivalent to Rs. 172,944 ± 1,548/ha/year and Rs. 148,105 ± 2,385/ha/year, respectively. The net returns obtained from the IOFS models were significantly higher than those obtained from the farmers' practice of maize-fallow or cultivation of maize followed by vegetable (~30% of the areas). It is expected that, with the certification of organic products, the income and livelihood of the farmers will improve further over the years. While Mr. Jrill Makroh's model supplied 95.1%, 82.0%, and 96.0% of the total N, P2O5, and K2O, respectively, needed by the system, Mrs. Skola Kurbah's model supplied 76.0%, 68.6%, and 85.5% of the total N, P2O5, and K2O, respectively.DiscussionThus, IOFS models should be promoted among hill farmers so that they can efficiently recycle farm resources and increase their productivity, net returns, and livelihood while reducing their dependence on external farm inputs.

Aims: There is a growing interest in the use of microbials in sustainable protected cultivation systems. A novel study on the influence of chili residue and plant growth-promoting rhizobacteria (PGPR) interaction was conducted to investigate the agronomic response of a greenhouse-grown leaf mustard (Brassica juncea L.), as well as the soil productivity. Methods: Bacillus subtilis (B1), B. laterosporus (B2), or B. amyloliquefaciens (B3) was inoculated on soil containing chili residue in a solar greenhouse. Other treatments were chili residue alone (NoPGPR) and chemical fertilizer (ChemFert). The crop photosynthesis, growth, yield, and quality, the soil chemical properties, microbial biomass, and the rhizospheric bacterial community were evaluated. Results: Residue and PGPR synergy significantly enhanced the leaf mustard's productivity and soil quality than NoPGPR and ChemFert. B1, B2, and B3 improved the crop yield by 51–63% than NoPGPR and ChemFert. They also increased the net photosynthetic rate, plant uptakes of N, P, K, Mg, Ca, Mn, Zn, and soil microbial quotient than NoPGPR and ChemFert, which comparatively elicited lower leaf chlorophyll-a, total soluble solids, nutrients uptakes compared to the PGPR treatments. Residue and B. laterosporus synergy markedly improved the soil organic carbon, total nitrogen, microbial carbon contents, and the microbial quotient. Further, 16S rRNA high throughput sequencing revealed that inoculating chili residue with B. laterosporus more consistently enriched the rhizospheric bacterial community composition at the phylum and genus levels, although with a lower diversity. Conclusions: Inoculating chili residue with B. laterosporus is a strategy with immense benefits as a bio-fertilizer for sustainable vegetable production, which also renders soil ecological services. [ABSTRACT FROM AUTHOR]

ABSTRACT The cultivation of grasses in sewage sludge (SS) with aeration has the potential for stabilization of sludge organic matter in the production of organic fertilizer. Thus, the objective of this work was to evaluate the cultivation of Urochloa brizantha and Pennisetum purpureum under aerated system on the chemical and biological attributes of SS to obtain a matured organic fertilizer. The study was conducted in a randomized block design in a 2x2+2 factorial scheme with four replications. Factors consisted of cultivation of P. purpureum or U. brizantha in SS, with or without intermittent aeration. Control treatments were SS without cultivation, with or without aeration. Sewage sludge was collected in layers and the chemical and microbial attributes were evaluated. There was no significant difference between treatments for grass dry matter. The C/N ratio was not matched with organic fertilizer stabilization due to similar losses of C and N (~7%). However, microbial activity was reduced in the presence of plant cultivation demonstrating improvement in the properties of the organic fertilizer produced. Through uni- and multivariate analysis, organic fertilizer produced from SS aerated and cultivated with P. purpureum showed matured organic matter.

The recommended dose of sewage sludge is based on the availability of mineral nitrogen and its mineralizable organic fraction, which varies according to sewage sludge, soil type, and several climatic factors. This study evaluated the mineralization and recovery of macronutrients from dried and composted sewage sludge in clayey, medium, and sandy soils textures for 120 days. The behavior of organic carbon (OC), mineral and organic nitrogen (ON), and the available P, K, Ca, and Mg in the soil were investigated. The sewage sludge showed to be an alternative source of P as it presented a mean availability rate higher than 72%. The most severe sewage sludge degradation occurred in the first weeks of monitoring. The highest OC mineralization rate (MR) were equal to or greater than 30% and occurred in the first 30 days of evaluation in all treatments. The MR for OC and ON in the soils that received the residues, at the end of 120 days of monitoring, were greater than 45%, indicating that in tropical soils the mineralization occurs intensely. Soil texture influenced the N mineralization of sewage sludge, with higher MR in the soils with higher sand concentration, for both residues. In field condictions, the application of dried and composted sewage sludge showed ON mineralization rates above 50% for clayey, medium, and sandy soils. [ABSTRACT FROM AUTHOR]

ABSTRACT The use of residues for agricultural production is an alternative for the achievement of sustainability. When mixed with diatomaceous earth (DE) from biofuel filtration, sewage sludge (SS) plays an important role as soil conditioning agent. As a result, the objective of this work was to make a DE vermicompost at different proportions: 0; 7.53; 15.06; 22.59 and 30.12% v/v in relation to a SS pre-compost (PC) and gardening pruning residues. The experiment was carried out in 100-L containers in a randomized block design, with 5 treatments and 5 replications, in which Eisenia foetida earthworms were used in the pre-composting and vermicomposting processes. After four months, the physical characteristics of the vermicompost were analyzed. It was verified that the diatomaceous earth can be vermicomposted, even when soaked in biofuel oil, at amounts of up to 30.12% v/v, with no visible physical damage to earthworms and plants, and this proportion of DE reduced the concentration of nutrients, but improved the physical properties of the vermicompost, making it an excellent physical conditioner for use as a substrate of plants and fertilization of soils.

The cultivation of grasses in sewage sludge (SS) with aeration has the potential for stabilization of sludge organic matter in the production of organic fertilizer. Thus, the objective of this work was to evaluate the cultivation of Urochloa brizantha and Pennisetum purpureum under aerated system on the chemical and biological attributes of SS to obtain a matured organic fertilizer. The study was conducted in a randomized block design in a 2x2+2 factorial scheme with four replications. Factors consisted of cultivation of P. purpureum or U. brizantha in SS, with or without intermittent aeration. Control treatments were SS without cultivation, with or without aeration. Sewage sludge was collected in layers and the chemical and microbial attributes were evaluated. There was no significant difference between treatments for grass dry matter. The C/N ratio was not matched with organic fertilizer stabilization due to similar losses of C and N (~7%). However, microbial activity was reduced in the presence of plant cultivation demonstrating improvement in the properties of the organic fertilizer produced. Through uni- and multivariate analysis, organic fertilizer produced from SS aerated and cultivated with P. purpureum showed matured organic matter. [ABSTRACT FROM AUTHOR]

The use of residues for agricultural production is an alternative for the achievement of sustainability. When mixed with diatomaceous earth (DE) from biofuel filtration, sewage sludge (SS) plays an important role as soil conditioning agent. As a result, the objective of this work was to make a DE vermicompost at different proportions: 0; 7.53; 15.06; 22.59 and 30.12% v/v in relation to a SS pre-compost (PC) and gardening pruning residues. The experiment was carried out in 100-L containers in a randomized block design, with 5 treatments and 5 replications, in which Eisenia foetida earthworms were used in the pre-composting and vermicomposting processes. After four months, the physical characteristics of the vermicompost were analyzed. It was verified that the diatomaceous earth can be vermicomposted, even when soaked in biofuel oil, at amounts of up to 30.12% v/v, with no visible physical damage to earthworms and plants, and this proportion of DE reduced the concentration of nutrients, but improved the physical properties of the vermicompost, making it an excellent physical conditioner for use as a substrate of plants and fertilization of soils. [ABSTRACT FROM AUTHOR]

The rice-maize cropping system (RMS) is an emerging option for diversification of the prevalent rice-wheat system (RWS) in South Asia. Studies underlined the significance of adequate potassium (K) nutrition for sustainable intensification of the RMS. Although studies on combined effects of tillage, residue retention, and nutrient management on crop yields and nutrient use efficiency for the RWS are plenty, such studies are scarce for the RMS. We, therefore, conducted a 5-year field study on sandy loam (Typic Ustochrept) soil at Modipuram, India to evaluate the effects of tillage and crop establishment, residue management and K fertilization on crop productivity, K use efficiencies, changes in soil K status, and apparent K balance under irrigated RMS in north-western India. Three combinations of tillage and crop establishment methods i.e., puddled transplanted rice (TPR) followed by conventional-till maize (TPR/CTM); conventional-till dry direct-seeded rice (CTDSR) followed by CTM (CTDSR/CTM); and zero-till DSR followed by zero-till maize (ZTDSR/ZTM) were considered as main plots. Sub-plot treatments consisted of two residue management options i.e., removal of residues (-R) of both crops, and partial residue retention (5 Mg ha −1 ) for rice and maize, either at soil surface in zero till (ZT) plots or incorporated into the soil in conventionally-till (CT) plots (+R). The sub-sub plot treatments were no-K application (-K) and 62 kg K ha −1 application (+K) to both rice and maize. Data summed-up for 5 years revealed that rice grain yield and K uptake under TPR were significantly higher ( p <  0.05) compared with CT/ZT DSR, irrespective of residue and K management options. The maize yield and K uptake were highest under the ZTDSR/ZTM treatment. Both rice and maize yields were significantly (p < 0.05) higher with 62 kg ha −1  K application under −R plots, but such effects were not significant under + R plots. Similarly the effect of residue management on yield and K uptake of rice and maize was significant only in the absence of fertilizer K application. Recycling of rice residue in maize had more pronounced effect on K uptake compared with that of maize residue in rice. Agronomic and recovery efficiencies of applied K were lower under +R plots, and agronomic efficiency was further decreased when both rice and maize were grown under ZT conditions (ZTDSR/ZTM). Soil exchangeable K content at 0–0.05 m and 0.05–0.15 m depths was significantly higher ( p <  0.05) under ZTDSR/ZTM compared with that under CTDSR/CTM and TPR/CTM treatments, and the values were greater under +R + K compared with −R−K treatments. Soil exchangeable K under −K−R plots dropped to 102 and 90 mg kg −1 at 0–0.05 m and 0.05–0.15 m depth, respectively vis–a-vis the initial K content (122 and 114 mg kg −1 , respectively). The apparent K balance, computed as K addition less K off-take by rice and maize during the study period of 5 years, was invariably negative in the absence of K fertilizer i.e., −307 kg ha −1 in TPR/CTM (+R−K) to −1483 kg ha −1 in ZTDSR/ZTM (−R−K) treatments. On contrary, the apparent K balance was positive in +R + K plots under different tillage and crop establishment methods. Positive correlation between soil exchangeable K and K input indicated that soil K mining in the RMS could be mitigated to a great extent with adequate supply of K through residue retention and K fertilization. [ABSTRACT FROM AUTHOR]

[Display omitted] • Full life-cycle utilization of hydrophytes in CWs is discussed. • Nitrogen removal and GHGs reduction in CWs are simultaneously evaluated. • Optimization of plant species composition is a key to improve CW performance. • Construction of an ideal CW system from the viewpoint of hydrophytes is proposed. With the prominence of global climate change and proposal of carbon reduction concept, how to maximize the comprehensive effect of nitrogen removal and greenhouse gases (GHGs) reduction in constructed wetlands (CWs) has become crucial. As indispensable biological component of CWs, hydrophytes have received extensive attention owing to their application potential. This review comprehensively evaluates the functions of hydrophytes in nitrogen removal and GHGs reduction in CWs in terms of plants themselves, plant-mediated microbes and plant residues (hydrophyte carbon sources and hydrophyte-derived biochars). On this basis, the strategies for constructing an ideal CW system are put forward from the perspective of full life-cycle utilization of hydrophytes. Finally, considering the variability of plant species composition in CWs, outlooks for future research are specifically proposed. This review provides guidance and novel perspectives for the full life-cycle utilization of hydrophytes in CWs, as well as for the construction of an ideal CW system. [ABSTRACT FROM AUTHOR]

Under changing climate scenarios, developing sustainable adaptation strategies in agriculture will be obligatory. To understand the effect of carbohydrate-based superabsorbent polymer (SAP) and crop-residue mulch (CRM) on pearl millet productivity and water-use efficiency (WUE), field experiments were undertaken for three consecutive years at 11 different locations (representing ⁓30 % of the global pearl millet growing area). Eight treatments, namely, Control; CRM 5.0 t/ha; SAP 2.5 kg/ha; SAP 5.0 kg/ha; SAP 7.5 kg/ha; SAP 2.5 kg/ha + CRM 5.0 t/ha; SAP 5.0 kg/ha + CRM 5.0 t/ha and SAP 7.5 kg/ha + CRM 5.0 t/ha were evaluated. Co-application of CRM and SAP increased pearl millet grain and stover yield by up to ⁓45 % and ⁓36 %, respectively. Pearl millet responded significantly up to 2.5 kg/ha SAP application (with or without CRM) only. Further, soil microbial biomass carbon improved significantly with CRM (20 %) and SAP (10.9–12.1 %) individually and with simultaneous application of CRM and SAP (⁓30 %). Likewise, dehydrogenase, alkaline phosphatase, acid phosphatase, and urease activities also improved significantly due to the co-use of CRM and SAP. Positive effects of CRM, SAP, and their co-application were also witnessed on soil microbial (bacterial, fungal, actinobacteria) populations and water-use efficiency (WUE) across environments. Among the locations, New Delhi and Aurangabad were the most desirable and stable ecologies, whereas Bikaner and Vijayapur remained the least consistent. Hence, to tackle the moisture-stress problem under pearl millet production systems and to achieve stable productivity, greater WUE and better soil microbial activity, CRM 5 t/ha in conjunction with SAP 2.5 kg/ha may be recommended across diverse ecologies. • Pearl millet is a climate resilient futuristic nutri-cereal crop. • Co-use of polymers and organic mulches assists in soil moisture conservation. • Moisture-conservation leads to reduced stress and enhanced soil microbial activity. • GGE tool helps to know the best and stable treatment across various interactions. [ABSTRACT FROM AUTHOR]

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Although biodiesel is among the most studied biofuels for diesel engines, it is usually produced from edible oils, which gives way to controversy between the use of land for fuel and food. For this reason, residues like olive-pomace oil are considered alternative raw materials to produce biodiesel that do not compete with the food industry. To gain knowledge about the implications of its use, olive-pomace oil methyl ester, straight and blended with diesel fuel, was evaluated as fuel in a direct injection diesel engine Perkins AD 3-152 and compared to the use of fossil diesel fuel. Performance curves were analyzed at full load and different speed settings. To perform the exergy balance of the tested fuels, the operating conditions corresponding to maximum engine power values were considered. It was found that the tested fuels offer similar performance parameters. When straight biodiesel was used instead of diesel fuel, maximum engine power decreased to 5.6%, while fuel consumption increased up to 7%. However, taking into consideration the Second Law of the Thermodynamics, the exergy efficiency and unitary exergetic cost reached during the operation of the engine under maximum power condition for the assessed fuels do not display significant differences. Based on the exergy results, it may be concluded that olive-pomace oil biodiesel and its blends with diesel fuel may substitute the use of diesel fuel in compression ignition engines without any exergy cost increment. [ABSTRACT FROM AUTHOR]

Many life cycle assessment studies have evaluated and compared the environmental performance of various technologies for recycling plastic containers and packaging in Japan and other countries. However, no studies have evaluated the combination of recycling technologies in consideration of the resin composition in terms of the quantity of each recycled product so as to maximize their environmental potential. In this study, 27 scenarios of recycling schemes for household waste plastic containers and packaging are developed through integrating a conventional recycling scheme with additional recycling schemes. The conventional recycling scheme involves municipal curbside collection and either the material recycling or feedstock recycling of waste plastics. The additional recycling schemes are feedstock recycling in steel works of the residue from conventional material recycling processes, and corporate voluntary collection and independent material recycling of specific types of plastic trays. Life cycle assessment based on the modeling of recycling processes considering the resin composition in terms of the quantity of each recycled product is applied to evaluate and compare these scenarios from the viewpoints of fossil resource consumption and CO emission. The results show that the environmental loads are reduced in all scenarios including the additional recycling schemes compared with the conventional recycling scheme. However, the independent plastic tray recycling scheme exhibits lower additional environmental savings when the residue recycling scheme is integrated with the conventional material recycling scheme. This is because both additional recycling schemes aim to utilize polystyrene and polyethylene terephthalate, which would otherwise be incinerated as residue from material recycling processes. The evaluation of the environmental loads of plastic recycling with consideration of the resin composition in terms of the quantity of each recycled product makes it possible to investigate recycling schemes that integrate different technologies to maximize their environmental potential. [ABSTRACT FROM AUTHOR]

We investigated a new kind of activated carbon named gaiasafe-Formstoff [1] as an agent for powerful heavy metal reduction. This activated carbon contains highly dispersed sulfide compounds. Our investigations with lead containing wastewaters showed an outstanding metal sulfide precipitation power of the new agent. The lead reduction rates are independent of wastewater parameters like lead concentration and complexing agent concentration. Contacted as powder or as a fixed bed with wastewater gaiasafe-Formstoff showed the best cleaning capacity in comparison to all other agents tested. Investigations with gaiasafe-Formstoff about its ability to reduce the contents of further heavy metals in wastewater are under way. The gaiasafe-Formstoff reaction products with wastewater represent an energy-rich and raw material-rich resource when fed to metallurgical processes. [ABSTRACT FROM AUTHOR]