Slaughterhouse waste (or abattoir waste) disposal has been a major environmental challenge in all parts of the world. The chemical properties of slaughterhouse wastes are similar to that of municipal sewage, however the former is highly concentrated wastewater with 45% soluble and 55% suspended organic composition. Blood has a very high COD of around 375,000 mg/L and is one of the major dissolved pollutants in slaughterhouse wastewater.
In most of the developing countries, there is no organized strategy for disposal of solid as well as liquid wastes generated in abattoirs. The solid slaughterhouse waste is collected and dumped in landfills or open areas while the liquid waste is sent to municipal sewerage system or water bodies, thus endangering public health as well as terrestrial and aquatic life. Wastewater from slaughterhouses is known to cause an increase in the BOD, COD, total solids, pH, temperature and turbidity, and may even cause deoxygenation of water bodies.
Anaerobic Digestion of Slaughterhouse Wastes
There are several methods for beneficial use of slaughterhouse wastes including biogas generation, fertilizer production and utilization as animal feed. Anaerobic digestion is one of the best options for slaughterhouse waste management which will lead to production of energy-rich biogas, reduction in GHGs emissions and effective pollution control in abattoirs.
Anaerobic digestion can achieve a high degree of COD and BOD removal from slaughterhouse effluent at a significantly lower cost than comparable aerobic systems. The biogas potential of slaughterhouse waste is higher than animal manure, and reported to be in the range of 120-160 m3 biogas per ton of wastes. However the C:N ratio of slaughterhouse waste is quite low (4:1) which demands its co-digestion with high C:N substrates like animal manure, food waste, crop residues, poultry litter etc.
Slaughterhouse effluent has high COD, high BOD, and high moisture content which make it well-suited to anaerobic digestion process. Slaughterhouse wastewater also contains high concentrations of suspended organic solids including pieces of fat, grease, hair, feathers, manure, grit, and undigested feed which will contribute the slowly biodegradable of organic matter. Amongst anaerobic treatment processes, the up-flow anaerobic sludge blanket (UASB) process is widely used in developing countries for biogas production from abattoir wastes.
Slaughterhouse waste is a protein-rich substrate and may result in sulfide formation during anaerobic degradation. The increased concentration of sulfides in the digester can lead to higher concentrations of hydrogen sulfide in the biogas which may inhibit methanogens. In addition to sulfides, ammonia is also formed during the anaerobic digestion process which may increase the pH in the digester (>8.0) which can be growth limiting for some VFA-consuming methanogens.
High oil prices, competing demands between foods and other biofuel sources, and the world food crisis, have ignited interest in algaculture (farming of algae) for making vegetable oil, biodiesel, bioethanol, biogasoline, biomethanol, biobutanol and other biofuels. Algae can be efficiently grown on land that is not suitable for agriculture and hold huge potential to provide a non-food, high-yield source of biodiesel, ethanol and hydrogen fuels.
Several recent studies have pointed out that biofuel from microalgae has the potential to become a renewable, cost-effective alternative for fossil fuel with reduced impact on the environment and the world supply of staple foods, such as wheat, maize and sugar.
What are Algae?
Algae are unicellular microorganisms, capable of photosynthesis. They are one of the world’s oldest forms of life, and it is strongly believed that fossil oil was largely formed by ancient microalgae. Microalgae (or microscopic algae) are considered as a potential oleo-feedstock, as they produce lipids through photosynthesis, i.e. using only carbon , water, sunlight, phosphates, nitrates and other (oligo) elements that can be found in residual waters.
Oils produced by diverse algae strains range in composition. For the most part are like vegetable oils, though some are chemically similar to the hydrocarbons in petroleum.
Advantages of Algae
Apart from lipids, algae also produce proteins, isoprenoids and polysaccharides. Some strains of algae ferment sugars to produce alcohols, under the right growing conditions. Their biomass can be processed to different sorts of chemicals and polymers (Polysaccharides, enzymes, pigments and minerals), biofuels (e.g. biodiesel, alkanes and alcohols), food and animal feed (PUFA, vitamins, etc.) as well as bioactive compounds (antibiotics, antioxidant and metabolites) through down-processing technology such as transesterification, pyrolysis and continuous catalysis using microspheres.
Algae can be grown on non-arable land (including deserts), most of them do not require fresh water, and their nutritional value is high. Extensive R&D is underway on algae as raw material worldwide, especially in North America and Europe with a high number of start-up companies developing different options.
Most scientific literature suggests an oil production potential of around 25-50 ton per hectare per year for relevant algae species. Microalgae contain, amongst other biochemical, neutral lipids (tri-, di-, monoglycerides free fatty acids), polar lipids (glycolipids, phospholipids), wax esters, sterols and pigments. The total lipid content in microalgae varies from 1 to 90 % of dry weight, depending on species, strain and growth conditions.
In order to develop a more sustainable and economically feasible process, all biomass components (e.g. proteins, lipids, carbohydrates) should be used and therefore biorefining of microalgae is very important for the selective separation and use of the functional biomass components.
The term biorefinery was coined to describe the production of a wide range of chemicals and bio-fuels from biomass by the integration of bio-processing and appropriate low environmental impact chemical technologies in a cost-effective and environmentally sustainable.
If biorefining of microalgae is applied, lipids should be fractionated into lipids for biodiesel, lipids as a feedstock for the chemical industry and essential fatty acids, proteins and carbohydrates for food, feed and bulk chemicals, and the oxygen produced can be recovered as well.
The potential for commercial algae production, also known as algaculture, is expected to come from growth in translucent tubes or containers called photo bioreactors or in open systems (e.g. raceways) particularly for industrial mass cultivation or more recently through a hybrid approach combining closed-system pre-cultivation with a subsequent open-system. Major advantages of a algal biorefinery include:
Use of industrial refusals as inputs ( CO2,wastewater and desalination plant rejects)
Large product basket with energy-derived (biodiesel, methane, ethanol and hydrogen) and non-energy derived (nutraceutical, fertilizers, animal feed and other bulk chemicals) products.
Not competing with food production (non-arable land and no freshwater requirements)
Better growth yield and lipid content than crops.
Indeed, after oil extraction the resulting algal biomass can be processed into ethanol, methane, livestock feed, used as organic fertilizer due to its high N:P ratio, or simply burned for energy cogeneration (electricity and heat). If, in addition, production of algae is done on residual nutrient feedstock and CO2, and production of microalgae is done on large scale in order to lower production costs, production of bulk chemicals and fuels from microalgae will become economically, environmentally and ethically extremely attractive.
With population of approximately 1.75 million, waste management is one of the most serious challenges confronting the local authorities. The daily solid waste generation across Gaza is more than 1300 tons which is characterized by per capita waste generation of 0.35 to 1.0 kg. Scarcity of waste disposal sites coupled with huge increase in waste generation is leading to serious environmental and human health impacts on the population.
The severity of the crisis is a direct consequence of continuing blockade by Israeli Occupation Forces and lack of financial assistance from international donor. Israeli Occupation Forces deliberately destroyed most of the sewage infrastructure in the Gaza Strip, during 2008-2009 Gaza War inflicting heavy damage to sewage pipes, water tanks, wastewater treatment plants etc.
There are three landfills in Gaza Strip – one each in southern and central part of Gaza and one in Gaza governorate. In addition, there are numerous unregulated dumpsites scattered across rural and urban areas which are not fenced, lined or monitored. Around 52% of the MSW stream is made up of organic wastes.
Domestic, industrial and medical wastes are often dumped near cities and villages or burned and disposed of in unregulated disposal sites which cause soil, air and water pollution, leading to health hazards and ecological damage. The physical damage caused to Gaza’s infrastructure by repeated Israeli aggression has been a major deterred in putting forward a workable solid waste management strategy in the Strip.
The sewage disposal problem is assuming alarming proportions. The Gaza Strip’s sewage service networks cover most areas, except for Khan Yunis and its eastern villages where only 40% of the governorate is covered. There are only three sewage water treatment stations in Gaza Strip – in Beit Lahia, Gaza city and Rafah – which are unable to cope with the increasing population growth rate. The total quantity of produced sewage water is estimated at 45 million m3 per annum, in addition to 3000 cubic meters of raw sewage sludge discharged from Gaza Strip directly into the sea every day. Sewage water discharge points are concentrated on the beaches of Gaza city, Al Shate’ refugee camp and Deir El Balah.
The continuous discharge of highly contaminated sewage water from Gaza Strip in the Mediterranean shores is causing considerable damage to marine life in the area. The beaches of Gaza City are highly polluted by raw sewage. In addition, groundwater composition in Gaza Strip is marked by high salinity and nitrate content which may be attributed to unregulated disposal of solid and liquid wastes from domestic, industrial and agricultural sources. The prevalent waste management scenario demands immediate intervention of international donors, environmental agencies and regional governments in order to prevent the situation from assuming catastrophic proportions.
The pharmaceutical industry has a substantial impact on the environment, especially when the materials used to make them and the chemicals that comprise make their way directly into the environment. The pharmaceutical industry at large as well as average consumer can take steps to make of use of medicine more sustainable through both significant and relatively minor changes.
Medicines and the Environment
The drugs that we consume naturally enter our environment as our body turns them to waste. This issue becomes exacerbated when people intentionally dispose of unused medicine by flushing it down the drain.
Although our water treatment systems are designed to take contaminants out of our wastewater before we re-introduce to the natural environment, some still get through. These contaminants, which include those in medications, can damage the ecosystems they end up in.
High levels of estrogen in waters due to birth control, for example, can hamper the ability of fish to reproduce, reducing their population size. Once those chemicals find their way into the water, they enter the food chain and eventually impact animals that live on land too, including humans.
Plants will absorb the chemicals from medications. Animals then eat these plants or drink the water and ingest the contaminants. Humans might drink the water or eat the plants or animals, making pollution from pharmaceuticals a human health hazard as well. This problem becomes worse in the summer when livestock such as cattle require two to three times as much water as they do during other times of the year.
Some communities have drug take-back programs that the Drug Enforcement Administration (DEA) approves. Some pharmacies also allow you to mail in or dispose of unused medications at kiosks. The DEA also organizes a national drug take-back day.
Although certain medications have recommendations on the label to flush them, you can dispose of the majority of them in your regular trash at home. The FDA recommends mixing them with something unpalatable such as dirt, kitty litter or coffee grounds in a plastic bag that you can seal. This disguises the drugs and prevents pets from getting into them. You can then throw the bag away.
If you are a throwing away a prescription medication container, be sure to scratch out all potentially identifying information to protect your privacy and identity.
Using Medicines More Sustainably
Another option for reducing the impact your use of medicine has on the environment is to use less of it or use more environmentally friendly medications.
To use less medicine, only use it when you truly need it and try substituting natural remedies for pharmaceuticals. Reach for naturally derived treatments such as essential oils, vitamins, herbs or a cup of hot tea. Always consult with your doctor before changing your medication regimen.
As a long-term strategy, regular exercise and a healthy diet can do wonders in improving your overall health and decreasing your need to take medicines.
Sustainability from the Industry’s Perspective
Of course, making the pharmaceutical industry more sustainable isn’t the sole responsibility of the consumer. The industry can also change its practices to manage pharmaceuticals in a more environmentally friendly fashion.
One aspect of this involves energy use. The manufacturing and transportation of medications can be extremely energy-intensive. By using energy more efficiently and using cleaner energy, drug companies can reduce their environmental impact.
Pharmaceutical industry can change its practices to manage pharmaceuticals in a more ecofriendly manner.
These corporations can also make an effort to include more eco-friendly substances in their medications. While they may not be able to remove every non-natural chemical from their products, they can offer greener alternatives to consume and look into reducing the presence of damaging substances as much as possible.
This applies not only to the organizations closest to the consumers but to the entire supply chain.
Medications are often vital to our health, but it can also have a negative impact on the health of our environment. Taking steps to manage pharmaceuticals more sustainably can enable us to protect our own well-being as well as that of our environment.
When you think of oil companies, it’s likely you don’t also think of “environmentally-friendly”. We see news about spilled oil, burning tankers, and other issues, and assume that all oil companies are disregarding the health of our planet. This simply isn’t the case, and you’ll be happy to know that the oil industry is actually working to keep the environment clean.
Here are five ways the industry is helping out with Mother Earth.
The first step to improving anything is realizing there’s a problem to begin with, then gathering necessary information on the problem. Every time a spill, accident, or fire occurs, the oil industry is gathering precious data to use to combat future problems.
When a spill occurs, it can be devastating for the local ecosystems. Flora and fauna alike are affected by the viscous liquid, often restricting their ability to move, breathe, or perform daily functions. The Deepwater Horizon Rig that caused a massive spill in the Gulf of Mexico in 2010 was much more than just an industrial and environmental disaster; it was a learning experience for the oil industry.
Scientists and researchers from all over the world descended on the Gulf after the spill, and though we’re still learning from it a decade later, the information that was collected has been incredibly beneficial to the industry and has helped pave the way for new containment processes.
2. Better Pipe Maintenance
Maintaining pipelines is a crucial component of keeping the environment clean. Pipes can rupture, leaking oil or natural gas into the environment or even causing explosions and fires under the right conditions. The oil and natural gas industries have focused heavily on creating better maintenance processes and safety standards for pipelines across the country in recent years.
Not only do faulty pipelines put the environment at risk, but they also put thousands of workers at risk as well. Keeping workers and the environment safe not only shows care for the Earth and the industry’s employees but also helps potentially save millions in cleanup dollars.
3. Decreasing Freshwater Usage
Certain processes, such as fracking or separating oil from sands, use millions of gallons of fresh water. This is incredibly damaging to the environment not only because there’s already a shortage of freshwater on a global scale, but also because the wastewater that’s produced is stored in man-made containment units that aren’t always good at containing it.
Fracking wastewater is laced with chemicals that are both harmful to the environment directly and can contaminate other freshwater sources. The oil industry is working hard to minimize the use of freshwater in fracking and separation processes, as well as reducing the amount of wastewater and improving containment.
There’s also some promise in the area of recycling the water itself for use in future processes. In the US, produced water from fracking is being used in certain applications and even some water treatment plants are focusing on better treatment processes to make the water drinkable.
4. Investing In Renewable Energy
Renewable energy is on the horizon, and with the continued focus on wind, solar, hydro, and even tidal energy, the oil industry is starting to take notice. These energy sources offer a promising future, but as of yet, they’re not able to meet the world’s energy demands in an affordable way.
Right now, gasoline, natural gas, and crude oil are much cheaper and more profitable to source, acquire, and sell to the public. Pipelines can transport natural gas thousands of miles away, serving isolated regions and maintaining a constant flow of raw resources throughout the country.
Not to mention, the Canadian economy is highly invested in oil and natural gas, being the 5th and 6th largest producer of each respectively. However, the oil industry isn’t ignoring renewables. With continued investments, we could see a partial or full transition to renewable energy within our lifetime.
5. Using Technology For Better Planning
As technology improves, so too do the processes by which pipelines are planned and built. With new software, engineers can better plan a pipe’s path through an ecosystem in order to minimize the environmental impact. Better diagnostic software can identify issues long before they become spills or ruptures, and even AI tech is playing a role in the oil industry.
Believe it or not, the oil industry is committed to a safer and more sustainable world. By using technology and data, the industry is improving its processes and ensuring that renewable energy remains an option for the future of energy production.
With ‘green’ being the buzzword across all industries, greening of the business sector and development of green skills has assumed greater importance all over the world. SMEs, startups and ecopreneurs are playing a vital role in the transition to a low-carbon economy by developing new green business models for different industrial sectors. Infact, young and small firms are emerging as main drivers of radical eco-innovation in the industrial and services sectors.
What are Green SMEs
Green SMEs adopt green processes and/or those producing green goods using green production inputs. A judicious exploitation of techno-commercial opportunities and redevelopment of business models, often neglected by established companies, have been the major hallmarks of green SMEs.
For example, SMEs operating in eco-design, green architecture, renewable energy, energy efficiency and sustainability are spearheading the transition to green economy across a wide range of industries. The path to green economy is achieved by making use of production, technology and management practices of green SMEs. Impact investment platforms allows individuals to invest in environmentally sustainable companies.
Categories of Green Industries
Protection of ambient air
Protection of climate
Management of forest resources
Management of flora and fauna
Noise and vibration abatement
Management of minerals
Protection of biodiversity and landscape
Protection against radiation
Natural resource management activities
Protection of soil, groundwater and surface water
Environmental Monitoring and Instrumentation
Research and Development
Research and Development
The key motivations for a green entrepreneur are to exploit the market opportunity and to promote environmental sustainability. A green business help in the implementation of innovative solutions, competes with established markets and creates new market niches. Green entrepreneurs are a role model for one and all as they combine environmental performance with market targets and profit outcomes, thus contributing to the expansion of green markets.
Some of the popular areas in which small green businesses have been historically successful are renewable energy production (solar, wind and biomass), smart metering, building retrofitting, hybrid cars and waste recycling.
As far as established green industries (such as waste management and wastewater treatment) are concerned, large companies tend to dominate, however SMEs and start-ups can make a mark if they can introduce innovative processes and systems. Eco-friendly transformation of existing practices is another attractive pathway for SMEs to participate in the green economy.
The Way Forward
Policy interventions for supporting green SMEs, especially in developing nations, are urgently required to overcome major barriers, including knowledge-sharing, raising environmental awareness, enhancing financial support, supporting skill development and skill formation, improving market access and implementing green taxation.
In recent decades, entrepreneurship in developing world has been increasing at a rapid pace which should be channeled towards addressing water, energy, environment and waste management challenges, thereby converting environmental constraints into business opportunities.
Food waste is a global issue that begins at home and as such, it is an ideal contender for testing out new approaches to behaviour change. The behavioural drivers that lead to food being wasted are complex and often inter-related, but predominantly centre around purchasing habits, and the way in which we store, cook, eat and celebrate food.
Consumer Behavior – A Top Priority
Consumer behaviour is a huge priority area in particular for industrialised nations – it is estimated that some western societies might be throwing away up to a third of all food purchased. The rise of cheap food and convenience culture in recent years has compounded this problem, with few incentives or disincentives in place at producer, retail or consumer level to address this.
While it is likely that a number of structural levers – such as price, regulation, enabling measures and public benefits – will need to be pulled together in a coherent way to drive progress on this agenda, at a deeper level there is a pressing argument to explore the psycho-social perspectives of behaviour change.
Individual or collective behaviours often exist within a broader cultural context of values and attitudes that are hard to measure and influence. Simple one-off actions such as freezing leftovers or buying less during a weekly food shop do not necessarily translate into daily behaviour patterns. For such motivations to have staying power, they must become instinctive acts, aligned with an immediate sense of purpose. The need to consider more broadly our behaviours and how they are implicated in such issues must not stop at individual consumers, but extend to governments, businesses and NGOs if effective strategies are to be drawn up.
Emergence of Food Waste Disposers
Food waste disposer (FWDs), devices invented and adopted as a tool of convenience may now represent a unique new front in the fight against climate change. These devices, commonplace in North America, Australia and New Zealand work by shredding household or commercial food waste into small pieces that pass through a municipal sewer system without difficulty.
The shredded food particles are then conveyed by existing wastewater infrastructure to wastewater treatment plants where they can contribute to the generation of biogas via anaerobic digestion. This displaces the need for generation of the same amount of biogas using traditional fossil fuels, thereby averting a net addition of greenhouse gases (GHG) to the atmosphere.
Food waste is an ideal contender for testing new approaches to behaviour change.
The use of anaerobic digesters is more common in the treatment of sewage sludge, as implemented in the U.K., but not as much in the treatment of food waste. In addition to this, food waste can also replace methanol (produced from fossil fuels) and citric acid used in advanced wastewater treatment processes which are generally carbon limited.
Despite an ample number of studies pointing to the evidence of positive impacts of FWDs, concerns regarding its use still exist, notably in Europe. Scotland for example has passed legislation that bans use of FWDs, stating instead that customers must segregate their waste and make it available curbside for pickup. This makes it especially difficult for the hospitality industry, to which the use of disposer is well suited. The U.S. however has seen larger scale adoption of the technology due to the big sales push it received in the 1950s and 60s. In addition to being just kitchen convenience appliances, FWDs are yet to be widely accepted as a tool for positive environmental impact.
Note: Note: This excerpt is being published with the permission of our collaborative partner Be Waste Wise. The original excerpt and its video recording can be found at this link
The olive oil industry offers valuable opportunities to farmers in terms of seasonal employment as well as significant employment to the off-farm milling and processing industry. While this industry has significant economic benefits in regards to profit and jobs; the downside is it leads to severe environmental harm and degradation. In 2012, an estimated 2,903,676 tons of olive oil was produced worldwide, the largest olive oil producers being Spain, Italy, and Greece followed by Turkey and Tunisia and to a lesser extent Portugal, Morocco and Algeria. Within the European Union’s olive sector alone, there are roughly 2.5 million producers, who make up roughly one-third of all EU farmers.
Types of Wastes
Currently, there are two processes that are used for the extraction of olive oil, the three-phase and the two-phase. Both systems generate large amounts of byproducts. The two byproducts produced by the three-phase system are a solid residue known as olive press cake (OPC) and large amounts of aqueous liquid known as olive-mill wastewater (OMW). The three-phase process usually yields 20% olive oil, 30% OPC waste, and 50% OMW. This equates to 80% more waste being produced than actual product.
Regardless of system used, the effluents produced from olive oil production exhibit highly phytotoxic and antimicrobial properties, mainly due to phenols. Phenols are a poisonous caustic crystalline compound. These effluents unless disposed of properly can result in serious environmental damage. There is no general policy for waste management in the olive oil producing nations around the world. This results in inconsistent monitoring and non-uniform application of guidelines across these regions.
State of Affairs
Around 30 million m3 of olive mill wastewater is produced annually in the Mediterranean area. This wastewater cannot be sent to ordinary wastewater treatment systems, thus, safe disposal of this waste is of serious environmental concern. Moreover, due to its complex compounds, olive processing waste (OPW) is not easily biodegradable and needs to be detoxified before it can properly be used in agricultural and other industrial processes.
This poses a serious problem when the sophisticated treatment and detoxification solutions needed are too expensive for developing countries in North Africa, such as Morocco, Algeria and Tunisia, where it is common for OMW to be dumped into rivers and lakes or used for farming irrigation. This results in the contamination of ground water and eutrophication of lakes, rivers and canals. Eutrophication results in reductions in aquatic plants, fish and other animal populations as it promotes excessive growth of algae. As the algae die and decompose, high levels of organic matter and the decomposing organisms deplete the water of oxygen, causing aquatic populations to plummet.
Another common tactic for disposal of olive mill wastewater is to collect and retain it in large evaporation basins or ponds. It is then dried to a semi-solid fraction. In less developed countries where olive processing wastes is disposed of, this waste, as well as olive processing cake and SOR waste is commonly unloaded and spread across the surrounding lands where it sits building up throughout the olive oil production season. Over time these toxic compounds accumulate in the soil, saturating it, and are often transported by rain water to other nearby areas, causing serious hazardous runoff. Because these effluents are generally untreated it leads to land degradation, soil contamination as well as contamination of groundwater and of the water table itself.
Even a small quantity of olive wastewater in contact with groundwater has the potential to cause significant pollution to drinking water sources. The problem is more serious where chlorine is used to disinfect drinking water. Chlorine in contact with phenol reacts to form chlorophenol which is even more dangerous to human health than phenol alone.
The problems associated with olive processing wastes have been extensively studied for the past 50 years. Unfortunately, research has continued to fall short on discovering a technologically feasible, economically viable, and socially acceptable solution to OPW. The most common solutions to date have been strategies of detoxification, production system modification, and recycling and recovery of valuable components. Because the latter results in reductions in the pollution and transformation of OPW into valuable products, it has gained popularity over the past decade. Weed control is a common example of reusing OPW; due to its plant inhibiting characteristics OPW once properly treated can be used as an alternative to chemical weed control.
Research has also been done on using the semisolid waste generated from olive oil production to absorb oil from hazardous oil spills. Finally, in terms of health, studies are suggesting that due to OPW containing high amounts of phenolic compounds, which have high in antioxidant rates, OPW may be an affordable source of natural antioxidants. Still, none of these techniques on an individual basis solve the problem of disposal of OMW to a complete and exhaustive extent.
At the present state of olive mill wastewater treatment technology, industry has shown little interest in supporting any traditional process (physical, chemical, thermal or biological) on a wide scale.This is because of the high investment and operational costs, the short duration of the production period (3-5 months) and the small size of the olive mills.
Overall, the problems associated with olive processing wastes are further exemplified by lack of common policy among the olive oil producing regions, funding and infrastructure for proper treatment and disposal, and a general lack of education on the environmental and health effects caused by olive processing wastes.
While some progress has been made with regards to methods of treatment and detoxification of OPW there is still significant scope for further research. Given the severity of environmental impact of olive processing wastes, it is imperative on policy-makers and industry leaders to undertake more concrete initiatives to develop a sustainable framework to tackle the problem of olive oil waste disposal.
The conventional leather tanning technology is highly polluting as it produces large amounts of organic and chemical pollutants. Wastes generated by tanneries pose a major challenge to the environment. Anaerobic digestion of tannery wastes is an attractive method to recover energy from tannery wastes.
According to conservative estimates, more than 600,000 tons per year of solid waste are generated worldwide by leather industry and approximately 40–50% of the hides are lost to shavings and trimmings. Everyday a huge quantity of solid waste, including trimmings of finished leather, shaving dusts, hair, fleshing, trimming of raw hides and skins, are being produced from the industries. Chromium, sulphur, oils and noxious gas (methane, ammonia, and hydrogen sulphide) are the elements of liquid, gas and solid waste of tannery industries.
Biogas from Tannery Wastes
Anaerobic digestion (or biomethanation) systems are mature and proven processes that have the potential to convert tannery wastes into energy efficiently, and achieve the goals of pollution prevention/reduction, elimination of uncontrolled methane emissions and odour, recovery of biomass energy potential as biogas, production of stabilized residue for use as low grade fertilizer.
Anaerobic digestion of tannery wastes is an attractive method to recover energy from tannery wastes. This method degrades a substantial part of the organic matter contained in the sludge and tannery solid wastes, generating valuable biogas, contributing to alleviate the environmental problem, giving time to set-up more sustainable treatment and disposal routes. Digested solid waste is biologically stabilized and can be reused in agriculture.
Until now, biogas generation from tannery wastewater was considered that the complexity of the waste water stream originating from tanneries in combination with the presence of chroming would result in the poisoning of the process in a high loaded anaerobic reactor.
When the locally available industrial wastewater treatment plant is not provided by anaerobic digester, a large scale digestion can be planned in regions accommodating a big cluster of tanneries, if there is enough waste to make the facility economically attractive.
In this circumstance, an anaerobic co-digestion plant based on sludge and tanneries may be a recommendable option, which reduces the quantity of landfilled waste and recovers its energy potential. It can also incorporate any other domestic, industrial or agricultural wastes. Chrome-free digested tannery sludge also has a definite value as a fertilizer based on its nutrient content.
Potential Applications of Biogas
Biogas produced in anaerobic digesters consists of methane (50%–80%), carbon dioxide (20%–50%), and trace levels of other gases such as hydrogen, carbon monoxide, nitrogen, oxygen, and hydrogen sulfide. Biogas can be used for producing electricity and heat, as a natural gas substitute and also a transportation fuel. A combined heat and power plant (CHP) not only generates power but also produces heat for in-house requirements to maintain desired temperature level in the digester during cold season.
CHP systems cover a range of technologies but indicative energy outputs per m3 of biogas are approximately 1.7 kWh electricity and 2.5kWh heat. The combined production of electricity and heat is highly desirable because it displaces non-renewable energy demand elsewhere and therefore reduces the amount of carbon dioxide released into the atmosphere.
AD Plant at ECCO’s Tannery (Netherlands)
A highly advanced wastewater treatment plant and biogas system became fully operational in 2012 at ECCO’s tannery in the Netherlands. A large percentage of the waste is piped directly into the wastewater plant to be converted into biogas. This biogas digester provides a source of renewable fuel and also helps to dispose of waste materials by converting waste from both the leather-making processes, and the wastewater treatment plant, into biogas. All excess organic material from the hides is also converted into biogas.
This project enables ECCO Tannery to reduce waste and to substitute virtually all of its consumption of non-renewable natural gas with renewable biogas. The aim is to use more than 40% of the total tannery waste and replace up to 60% of the total natural gas consumption with biogas.
Zero Valent Iron (ZVI) was developed to eliminate chlorinated hydrocarbon solvents in the soil. Industrial solvents are replete with chlorinated hydrocarbon, so much toxic and bad for the environment. They get disposed in the soil along with other toxic elements to cause harm to our surrounding. In the current years, significant improvements have taken place in the realm of iron-based technology.
Zero Valent Iron can be effectively used in soil remediation
The result of years of research and significant improvement in the iron-based technology is the advent of nanoscale or polymer-supported iron-containing nanoparticles to remove contaminants from solvents and soil. This is all due to the high surface area to the volume ratio of such nanoscale particles that favor the reaction kinetics and sorption.
But, know one thing that high pressure drops may restrict fixed-bed column application. This is why we now have modified nanosized ferrous particles to facilitate arsenic removal. The fabulous reducing agent helps in pollution recovery, and thus it benefits our environment.
Applications of Zero Valent Iron
ZVI in recent times is used widely for wastewater treatment, groundwater, and soil treatment. If made through the physico-chemical process in combination, the ZVI may be very small particles, having a large surface area. ZVI is beneficial for the environment, for it has a strong reductibility, great purity, long aging property, and similar features.
Zerovalent Iron can boost the chlorine removal efficiency of the soil, groundwater, and six valent chromium. Thus, it reduces the time required for environmental remediation. Acting as a fabulous reducing agent, it facilitates pollution recovery. Indeed, you may also combine it to bioremediation to further improve the efficacy of environment pollution recovery. Use it in the soil, solvents and industrial wastewater confidently to get rid of the contaminants. The use of ZVI paves the way for pure water and soil.
What you should look for in ZVI?
Are you planning to procure zero valent elemental metallic ions for wastewater treatment or soil remediation? Zerovalent metals or ZVI has a wide range of applications that range from electrodes and trenches to filters. Yes! It helps in the water filtration process, and thus we have pure drinking water. It gets rid of every trace of impurity or contaminant from the solvent or soil. It is important to look for a reliable company to procure ZVI.
Watch out for the following properties of ZVI
The particles must be fine enough to be customized as per your application
Look for the great adsorption performance and sound chemical activity
A large surface area for that very strong reductibility
Make sure the duration of its effect is very long to reduce the injections
Very fine ZVI particles to remediate pollution and to save remediation time and effort
Must be environment-friendly, deprived of any toxic compound
Enhanced nitrate-removing potential
Zero-valent metal has an enhanced nitrate removal capacity. It eliminates nitrate from the groundwater to facilitate remediation. Hence, biochar-supported ZVI can facilitate nitrate removal while the ones with wider pH can remove larger nitrates. Biochar composite eliminates nitrate from the groundwater without leaving any harmful by-products. But, biochar has a variable nitrate-removal capacity.
ZVI biochar has a potential to reduce nitrate by mediating the redox potential, the electron transfer, pH and thus facilitates enhanced removal or reduction of nitrate from the solvent or soil. Everything revolves around the logic of intensifying chemical reduction in order to eliminate nitrate from the soil or groundwater.
Nitrate and How it Accumulates
Nitrate is the form of nitrogen, which lies beneath the cultivable land. Nitrate is water soluble and may move through the soil quite easily. Owing to its high mobility, it moves to the groundwater table. Once it has moved to the groundwater table, it persists there and deposits to a very high level.
Thus, shallow groundwater is also at a risk of contamination from chemicals of land surfaces. This is a matter of concern, and indeed, nitrate in water may harm human health, aquatic life, livestock life and contaminate the surface water. We can say that it is not that harmful to adult humans, but it can significantly affect the health of the infants. It may reduce the level of oxygen in the blood to cause ‘blue baby’ disorder.
Hence, biological denitrification, ion exchange, and reverse osmosis are the treatment processes to handle this issue. The use of ZVI is a way to denitrification and the key to attaining a safe nitrate level in the water. A zero-valent metallic reduction is an effective way to refine dirty and polluted water. As soon as ZVI is placed in the flowing water or is added to the flowing water, there starts the process of oxidizing. The resultant chain reaction will purify water or remove the contaminants.
A Tool to Remediate Acid Mine Drainage
AMD or Acid Mine Drainage is the most common source of metal in places like the Appalachians, Tennessee, and Kentucky. It is important to remediate acid mine drainage for it is highly acidic and toxic. It is the major contributor to the arsenic environment and something needs to be done. AMD is a rich source of heavy and corrosive metals, acidic in nature. Biological treatment of Acid Mine Drainage is cost-effective, efficient and environment-friendly.
Biotechnological processes are an asset when it comes to treating Acid Mine Drainage in an effective manner. ZVI is environmentally sustainable. When it is very complicated and difficult to treat or remediate Acid Mine Drainage, ZVI eases the process. It gets rid of harmful elements or potentially hazardous substances from AMD to separate metal from acid and toxic compounds. There isn’t a need to abandon a mine site just because there are acidic metal deposits. Mine metals can be reclaimed with ZVI, and herein lays the environmental benefit.
Recycling of metallurgical waste
It is important to treat AMD or Acid Mine Drainage. The ecological solution to separate toxic metals, to reclaim water in large quantities is gaining a lot of attention. ZVI and zero valent metals save our natural resources and prepare the toxic metals for the recycling process. This is only possible through the separation of the acidic part.
We can recycle gallons of water that lay in the pond and other water bodies. It drops the acid level in the water and metal while also prevents heavy metallic reactions. When Acid Mine Drainage is one of the serious concerns in the realm of coal mining, zero valent metals prevent any exposure of sulfur-rich mineral to the water and atmospheric oxygen.
Zero-valent metals can help in the treatment of contaminated zones through the process of remediation. Zero valent iron is the highly reactive powder for remediation of wastewater and soil and works fabulously on environmentally contaminated areas. This remediation solution is highly efficient and benefits our environment in multiple ways.
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