Investigating the feasibility of using agricultural waste as an adsorbent of gold ions in small scale gold processing plants

Reduction of food rations and shortages is one of the impacts of the increasing human population. Food sector industries then try to cope with the fast growing number of customers. Agribusiness sector gains its popularity in these recent years, including pig farm. The increase trend of animal farming industry is likely to bring increasing pollution problem unless effective treatment methods are used. The main problems related to the pig farm include odor nuisance and pig manure disposal. The existing land application of piggery wastewater is the traditional way to discharge the wastewater. This may yield in land and water contamination, due to the accumulation of unused nutrients by crop plant. A case study of a large commercial pig farm from Australia is proposed to apply in smaller scale in Indonesia. Operational strategies for the small-scale SBR (Sequencing Batch Reactor) treating piggery effluent were developed based on lab-scale experiments. Due to SBR characteristics, which are money-saving and space-saving, it is very suitable to be applied in urban area. An economic evaluation was made of various process options. The cost estimation showed that SBR is a cost effective process, allowing operational batches to be adjusted to reduce unnecessary aeration cost. A reduction in the aeration cost was achieved by shortening the batch time from 24-h to 8-h. A comparison of three different SBR options showed that smaller size reactors could be more flexible and cost effective when compared with the larger ones.

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SPEAR (Solar Pyrolysis Energy Access Reactor): Theoretical Design and Evaluation of a Small-Scale Low-Cost Pyrolysis Unit for Implementation in Rural Communities

Energies ◽

10.3390/en14082189 ◽

2021 ◽

Vol 14 (8) ◽

pp. 2189

Author(s):

Cesare Caputo ◽

Ondřej Mašek

Keyword(s):

Waste Management ◽

Rural Areas ◽

Net Present Value ◽

Agricultural Waste ◽

Tracking Error ◽

Sub Saharan Africa ◽

Small Scale ◽

Energy Access ◽

Efficient System ◽

Pyrolysis Unit

Energy access and waste management are two of the most pressing developmental and environmental issues on a global level to help mitigate the accelerating impacts of climate change. They are particularly relevant in Sub–Saharan Africa where electrification rates are significantly below global averages and rural areas are lacking a formal waste management sector. This paper explores the potential of integrating solar energy into a biomass pyrolysis unit as a potentially synergetic solution to both issues. The full design of a slow pyrolysis batch reactor targeted at biochar production, following a strict cost minimization approach, is presented in light of the relevant considerations. SPEAR is powered using a Cassegrain optics parabolic dish system, integrated into the reactor via a manual tracking system and optically optimized with a Monte-Carlo ray tracing methodology. The design approach employed has led to the development an overall cost efficient system, with the potential to achieve optical efficiencies up 72% under a 1.5° tracking error. The outputs of the system are biochar and electricity, to be used for soil amendment and energy access purposes, respectively. There is potential to pyrolyze a number of agricultural waste streams for the region, producing at least 5 kg of biochar per unit per day depending on the feedstock employed. Financial assessment of SPEAR yields a positive Net Present Value (NPV) in nearly all scenarios evaluated and a reasonable competitiveness with small scale solar for electrification objectives. Finally, SPEAR presents important positive social and environmental externalities and should be feasibly implementable in the region in the near term.

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Identifying organic foulants on activated carbon from gold processing plants

Minerals Engineering ◽

10.1016/s0892-6875(00)00141-2 ◽

2000 ◽

Vol 13 (14-15) ◽

pp. 1581-1588 ◽

Cited By ~ 2

Author(s):

N.G Fisher ◽

J.G Dunn

Keyword(s):

Activated Carbon ◽

Gold Processing ◽

Processing Plants

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Biomass Potential from Agricultural Waste for Energetic Utilization in Greece

Energies ◽

10.3390/en12061095 ◽

2019 ◽

Vol 12 (6) ◽

pp. 1095 ◽

Cited By ~ 9

Author(s):

Spyridon Alatzas ◽

Konstantinos Moustakas ◽

Dimitrios Malamis ◽

Stergios Vakalis

Keyword(s):

Agricultural Waste ◽

Combined Heat And Power ◽

Biomass Energy ◽

Small Scale ◽

Energy Potential ◽

Annual Basis ◽

Mediterranean Countries ◽

Biomass Resources ◽

Gasification Technology

The alignment of the Greek national legislation with the corresponding EU legislation has enhanced the national efforts to pursue renewable Combined Heat and Power (CHP) projects. The scope of the present study has been the identification of the available biomass resources and the assessment of their potential. In this paper, we present the results from the administrative regions of Crete, Thessaly, and Peloponnese. The levels of lignocellulosic biomass in Greece are estimated to be 2,132,286 tonnes on an annual basis, values that are very close to the cases of other Mediterranean countries like Italy and Portugal. In respect to the total agricultural residues, Crete produces 1,959,124 tonnes/year and Thessaly produces 1,759,457 tonnes/year. The most significant streams are identified to be olive pits, olive pruning, and cotton ginning remnants, with more than 100,000 tonnes/year each. In the latter part of this manuscript, a case study is presented for the development of a CHP gasification facility in Messenia. The biomass energy potential of the area is very promising, with about 3,800,000 GJ/year. The proposed small-scale gasification technology is expected to utilize 7956 tonnes of biomass per year and to produce 6630 MWh of electricity and 8580 MWh of thermal energy.

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Nonlinear data reconciliation in gold processing plants

Minerals Engineering ◽

10.1016/j.mineng.2005.10.018 ◽

2006 ◽

Vol 19 (9) ◽

pp. 938-951 ◽

Cited By ~ 17

Author(s):

L.R.P. de Andrade Lima

Keyword(s):

Data Reconciliation ◽

Gold Processing ◽

Processing Plants

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Analysing electricity cost saving opportunities on South African gold processing plants

2015 International Conference on the Industrial and Commercial Use of Energy (ICUE) ◽

10.1109/icue.2015.7280247 ◽

2015 ◽

Cited By ~ 2

Author(s):

W. Hamer ◽

J.C. Vosloo ◽

R. Pelzer

Keyword(s):

Cost Saving ◽

South African ◽

Gold Processing ◽

Electricity Cost ◽

Processing Plants ◽

South African Gold

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Experimental Characterization of a Small-Scale Downdraft Gasifier for Biomass Waste

Volume 5: Energy Systems Analysis, Thermodynamics and Sustainability; NanoEngineering for Energy; Engineering to Address Climate Change, Parts A and B ◽

10.1115/imece2010-37392 ◽

2010 ◽

Cited By ~ 2

Author(s):

Vaughn M. Emmerson ◽

Gerardo Diaz

Keyword(s):

Agricultural Waste ◽

Molar Fraction ◽

Global Scale ◽

Small Scale ◽

Fuel Wood ◽

Biomass Waste ◽

Yard Waste ◽

Downdraft Gasifier ◽

Many Sources

Biomass is essentially organic garbage obtained from many sources of dead or live vegetation including yard waste. According to recent data, approximately sixty million bone dry tons of biomass are produced in California each year [1]. Of this, only five million tons are used for the generation of electricity. At a global scale, 8700 Tg of biomass (dry matter) were burned without energy recovery in 1991. This number has increased especially in developing countries with the main sources being the savannas, agricultural waste, tropical forests, and fuel wood. Inefficient burning of waste, through combustion in open-air or in open dumps are a significant source of pollutants leading to possible health effects. An alternative to open air combustion is gasification, which involves the conversion of biomass to generate synthesis gas (syngas) by adding heat and limited amounts of oxygen. Several gasifying agents can be utilized, but air is commonly used in small-scale gasifiers. The use of air causes a large molar fraction of nitrogen in the syngas composition. This papers shows the experimental results obtained with a commercially available small-scale downdraft gasifier. Woodchips obtained from a nearby landfill are used as input to the gasifier and temperatures, flow rates, and syngas composition are reported and analyzed.

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Economic indicators of production of semi-hard and hard cheeses in small capacity dairies in Serbia

Journal of Agricultural Sciences Belgrade ◽

10.2298/jas2003283m ◽

2020 ◽

Vol 65 (3) ◽

pp. 283-296

Author(s):

Dragan Milic ◽

Danica Glavas-Trbic ◽

Mirela Tomas-Simin ◽

Vladislav Zekic ◽

Tihomir Novakovic ◽

...

Keyword(s):

Dairy Products ◽

Production Costs ◽

Economic Indicators ◽

Small Scale ◽

Total Production ◽

Labor Costs ◽

Milk Processing ◽

Processing Plants ◽

The Cost ◽

Small Capacity

Animal husbandry has a longstanding tradition in Serbia, and the production of milk and dairy products has a rich legacy. Cow?s milk is used in the manufacture of all kinds of dairy products. Annual global cheese production is about 20 million tons, with cattle milk cheeses produced in large-scale processing plants constituting about 80% of that production. In Serbia, leaders of milk production are small family dairy farms, which contribute 92% of total production, while dairies with large capacity dominate in milk processing. There are 211 milk processing plants of varying capacities in Serbia. The largest amounts of milk are processed by dairy plants 'Imlek' and 'Subotica', while 188 small-scale dairies process 20% of total milk. The subject of this paper is the analysis of the economic indicators of production of semi-hard and hard cheeses in small-capacity dairies in Serbia. To determine the level and structure of production costs of dairy products, the analytical calculation method of per unit processing costs has been used. The study has revealed that the cost price of semi-hard and hard cheeses in small-capacity dairies amounts to 3.33 ?/kg. With 90.83% in the structure of total costs of processing the milk into cheese, the cost of raw materials has the largest share, followed by labor costs with 6.54%. For small-capacity dairies to be able to compete with larger dairies, both in product quality and price, it is crucial to continuously monitor and minimize production costs.

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