Generating Electricity from Municipal Solid Waste

We live in a throwaway society that accumulates vast quantities of waste every day. While this comes with pressing challenges, there are also opportunities for professionals including electrical engineers to process at least some of the waste to produce much-needed renewable energy.

According to the U.S. Energy Information Administration (EIA), in 2018 a total of 68 U.S. power plants generated around 14 billion kilowatt-hours of electricity from 29.5 million tons of combustible municipal solid waste (MSW). Biomass, which comes from plants and animals and is a source of renewable energy, was responsible for more than half (about 51%) of the electricity generated from waste. It also accounted for about 64% of the weight of the MSW used. The rest of the waste used was from other combustible materials including synthetic materials made from petroleum and plastics. Glass and metal are generally not noncombustible.

WTE_Plant_Belgium

Waste-to-Energy is now widely accepted as a part of sustainable waste management strategy.

Municipal Solid Waste in the U.S.

Burning MSW is not only a sustainable way to produce electricity, it also reduces the volume of waste that would inevitably end up in landfills. Instead, the EIA estimates that burning MSW effectively reduces waste volumes by about 87%.

But, while more than 268 million tons of MSW are generated in the United States every year, in 2017, only 12.7% of it was burned to recover energy. More than half (52.1%) went to landfill, about a quarter (25.1%) was recycled, and the rest (10.1%) was used to generate compost.

According to a U.S. Environmental Protection Agency (EPA) fact sheet on sustainable materials management published in November 2019, the total MSW generated in 2017 by material, comprised:

  • Paper and paperboard, primarily containers and packaging 25%
  • Food 15.2% (see below)
  • Plastics 13.2% (19.2% of the total materials that ended up in landfill were plastics)
  • Yard trimmings 13.1% (most of this type of waste is composted)
  • Rubber, leather and textiles 9.7%
  • Metals 9.4%
  • Wood 6.7%
  • Glass 4.2%
  • Other 3.5%

Indicating tremendous human waste in its worst form, 22% of the material that ended up in landfill was classified as food. Trashed food was also the product category with the highest landfill rate, at an alarming 75.3%. Nearly a quarter (22%) of materials that were combusted with energy recovery were food, and overall, food was also the highest product category to recover energy, with a rate of 18.4%.

The total MSW combusted to generate energy was made up of the following materials:

  • Food 22%
  • Plastics 16.4%
  • Rubber, leather, and textiles 16.1%
  • Paper and paperboard 13.2%
  • Wood 8.4%
  • Metals 8.6%
  • Yard trimmings 6.2%
  • Glass 4.3%
  • Other 4.3%

Generating Electricity from MSW

There are a variety of MSW-to-energy technologies, but in the U.S. the most common system involves mass burning of unprocessed MSW in a large incinerator that has a boiler that produces steam, and a generator that produces electricity. Another entails processing MSW into fuel pellets for use in smaller power plants.

Waste materials destined to be processed to generate electricity

Generating electricity in mass-burn WTE plants is remarkably straightforward and follows seven basic steps:

  1. The MSW is dumped out of garbage trucks into a large pit.
  2. A crane with a giant claw attachment is used to grab the waste and dump it into a combustion chamber.
  3. The waste, which now becomes the fuel, starts to burn, releasing heat.
  4. The heat that is released turns water in the boiler into high-pressure steam.
  5. The steam turns the turbine generator’s blades and produces electricity.
  6. The mass-burn plant incorporates an control system to prevent air pollution by removing pollutants from the combustion gas before it is released through a smoke-stack.
  7. Ash is inevitably produced in the boiler and the air pollution control system, and this has to be removed before another load of waste can be burned.

While the volumes burned as fuel in different plants vary, for every 100 pounds of MSW produced in the U.S., potentially, more than 85 pounds could be burned to generate electricity.

Of course, the U.S. isn’t the only country that uses waste-to-energy plants to generate electricity from MSW. And in fact, when compared to a lot of other countries, the percentage of MSW burned with energy recovery in the U.S. is minimal. At least nine countries are named by the EIA as bigger producers of electricity from municipal waste. In Japan and some European countries, for instance, there are fewer energy resources and not much open space available for landfills. So generating electricity from MSW is an obvious opportunity.

The four leading nations identified by the EIA as burning the most MSW with energy recovery are:

  • Japan 68%
  • Norway 54%
  • Switzerland 48%
  • France 35%
  • The United Kingdom 34%

One thing’s for certain, the percentages are all set to continue increases globally as the move towards sustainability gains momentum. And U.S. percentages are going to increase too.

Plastic Wastes and its Management

Plastic seems all pervasive and unavoidable. Since the 1960s our use of plastic has increased dramatically, and subsequently, the portion of our garbage that is made up of plastic has also increased from 1% of the total municipal solid waste stream (household garbage) to approximately 13% (US Environmental Protection Agency). Plastic products range from things like containers and packaging (soft drink bottles, lids, shampoo bottles) to durable goods (think appliances, furniture and cars) and non-durable goods including things from a plastic party tray to medical devices. Sometimes marked with a number and a chasing arrow, there is an illusion that all plastics are recyclable, and therefore recycled. But there are a number of problems with this assumption.

plastic-wastes

While use and consumption of plastic is increasingly high, doubts about viable options for reuse, recycling and disposal are also on the rise. Complications such as the increasing number of additives used alter the strength, texture, flexibility, colour, resistance to microbes, and other characteristics of plastics, make plastics less recyclable. Additionally, there is very little market value in some plastics, leading municipalities to landfill or incinerate plastics as waste. Based on figures from the EPA (2011 data) only 8% of plastic materials are recovered through recycling.

Another major concern about plastics in the waste stream is their longevity and whether or not they are truly biodegrade. It is estimated that most plastics would take 500-1000 years to break down into organic components. Because of this longevity and the low rate of recycling, much of our plastic waste ends up in landfills or as litter. Some of this plastic waste makes its way via rivers and wind to the ocean. Garbage barges, and the trans-continental transport of recyclable materials also lead to an increasing amount of plastics in our oceans and waterways.

Plastic waste directly and indirectly affects living organisms throughout the ecosystem, including an increasingly high impact on marine life at a macro and micro scale. According to United Nations, almost 80% of marine debris is plastic. Policy enforcement remains weak, global manufacture of plastics continues to increase, and the quantity of plastic debris in the oceans, as well as on land, is likely to increase.

With limited sustainable recovery of plastics, there is a growing global movement to reduce the generation of plastic. Certain types of plastic may be ’safer‘ for the environment than others, however, there are troubling issues associated with all of them, leading to the conclusion that action is needed to remove plastic waste, and stricter controls are required to limit new sources of plastic pollution. Efforts such as light weighting of packaging and shifts to compostable plastics are options. Many people use eco-friendly bags for the sake of green living. Policies limiting the use of plastics such as bottle bills and bag bans are other ways to decrease the production and consumption of plastics.

Mining the debris fields in our oceans and turning plastic waste into usable materials, from socks made of fishing line to fuel made from a variety of plastic debris, is one way to mitigate the current situation. You can do your part by using renewable cotton bags.

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

Solid Waste Management – India’s Burning Issue

For the first time in the history of India, the year 2012 saw several public protests against improper solid waste management all across India – from the northernmost state Jammu and Kashmir to the southernmost Tamil Nadu. A fight for the right to clean environment and environmental justice led the people to large scale demonstrations, including an indefinite hunger strike and blocking roads leading to local waste handling facilities. Improper waste management has also caused a Dengue Fever outbreak and threatens other epidemics. In recent years, waste management has been the only other unifying factor leading to public demonstrations all across India, after corruption and fuel prices. Public agitation resulted in some judicial action and the government’s remedial response, but the waste management problems are still unsolved and might lead to a crisis if this continues for too long without any long term planning and policy reforms.

Hunger Strike in Kerala

The President of Vilappilsala Village Panchayat went on a hunger strike recently, against her counterpart, the Mayor of Thiruvananthapuram. Thiruvananthapuram is the state capital of Kerala, and Vilappilsala is a village 22 km away. Since July 2000, about 80% of the waste generated in Thiruvananthapuram is being transported to a waste composting plant and a dumpsite in Vilappilsala village. Since the same month, respiratory illnesses reported in Vilappil Primary Health Center increased by 10 times from an average of 450 to 5,000 cases per month. People who used to regularly swim in the village’s aquifer started contracting infections; swarms of flies have ever since been pervasive; and a stigma of filth affected households throughout the community. This was a source of frustration as locals who, as Indians, prize the opportunity to feed and host guests, found them unwilling to even drink a glass of water in their homes. Currently, there is not a single household which has not experienced respiratory illnesses due to the waste processing plant and the adjoining dumpsite.

On the other hand, Thiruvananthapuram’s residents had to sneak out at night with plastic bags full of trash to dispose them behind bushes, on streets or in water bodies, and had to openly burn heaps of trash every morning for months. This was because the waste generated was not being collected by the City as it could not force open the composting plant and dumpsite against large scale protests by Vilappilsala’s residents. This is why in August – 2012, about 2,500 police personnel had to accompany trucks to the waste treatment plant as they were being blocked by local residents lying down on the road, and by some, including the village’s President, by going on an indefinite hunger strike.

Municipal Commissioner Replaced in Karnataka

In response to a similar situation in Bengaluru, the state capital of Karnataka, where the streets were rotting with piles of garbage for months, the municipal commissioner of the city was replaced to specifically address the waste management situation. Against the will of local residents, a landfill which was closed following the orders issued by the state’s pollution control board in response to public agitation had to be reopened soon after its closure as the city could not find a new landfill site.

Mavallipura landfill in Bangalore

Population density and the scale of increasing urban sprawl in India make finding new landfill sites around cities nearly impossible due to the sheer lack of space for Locally Unwanted Land Uses (LULUs) like waste management.

Dengue Outbreak in West Bengal

Even if partially because of improper waste management, Kolkata, state capital of West Bengal and the third biggest city in India experienced a Dengue Fever outbreak with 550 confirmed cases and 60 deaths. This outbreak coincides with a 600% increase in dengue cases in India and 71% increase in malarial cases in Mumbai in the last five years. Accumulation of rain water in non biodegradable waste littered around a city act as a major breeding environment for mosquitoes, thus increasing the density of mosquito population and making the transmission of mosquito related diseases like dengue, yellow fever and malaria easier.

Rabies in Srinagar

Rabies due to stray dog bites already kills more than 20,000 people in India every year. Improper waste management has caused a 1:13 stray dog to human ratio in Srinagar (compared to 1 per 31 people in Mumbai and 1 per 100 in Chennai), where 54,000 people were bitten by stray dogs in a span of 3.5 years. Municipal waste on streets and at the dumpsite is an important source of food for stray dogs. The ultimate solution to controlling stray dogs is proper waste management. The public has been protesting about this stray dog menace for months now with no waste management solutions in sight, but only partial short term measures like dog sterilization.

Energy Potential of Coconut Biomass

Coconuts are produced in 92 countries worldwide on about more than 10 million hectares. Indonesia, Philippines and India account for almost 75% of world coconut production with Indonesia being the world’s largest coconut producer. A coconut plantation is analogous to energy crop plantations, however coconut plantations are a source of wide variety of products, in addition to energy. The current world production of coconuts has the potential to produce electricity, heat, fiberboards, organic fertilizer, animal feeds, fuel additives for cleaner emissions, eco-friendly cutlery, health drinks, etc.

coconut-shell-biomass

The coconut fruit yields 40 % coconut husks containing 30 % fiber, with dust making up the rest. The chemical composition of coconut husks consists of cellulose, lignin, pyroligneous acid, gas, charcoal, tar, tannin, and potassium. Coconut dust has high lignin and cellulose content. The materials contained in the casing of coco dusts and coconut fibers are resistant to bacteria and fungi.

Coconut husk and shells are an attractive biomass fuel and are also a good source of charcoal. The major advantage of using coconut biomass as a fuel is that coconut is a permanent crop and available round the year so there is constant whole year supply. Activated carbon manufactured from coconut shell is considered extremely effective for the removal of impurities in wastewater treatment processes.

Coconut Shell

Coconut shell is an agricultural waste and is available in plentiful quantities throughout tropical countries worldwide. In many countries, coconut shell is subjected to open burning which contributes significantly to CO2 and methane emissions.

Coconut shell is widely used for making charcoal. The traditional pit method of production has a charcoal yield of 25–30% of the dry weight of shells used. The charcoal produced by this method is of variable quality, and often contaminated with extraneous matter and soil. The smoke evolved from pit method is not only a nuisance but also a health hazard.

The coconut shell has a high calorific value of 20.8MJ/kg and can be used to produce steam, energy-rich gases, bio-oil, biochar etc. It is to be noted that coconut shell and coconut husk are solid fuels and have the peculiarities and problems inherent in this kind of fuel.

Coconut shell is more suitable for pyrolysis process as it contain lower ash content, high volatile matter content and available at a cheap cost. The higher fixed carbon content leads to the production to a high-quality solid residue which can be used as activated carbon in wastewater treatment. Coconut shell can be easily collected in places where coconut meat is traditionally used in food processing.

Coconut Husk

Coconut husk has high amount of lignin and cellulose, and that is why it has a high calorific value of 18.62MJ/kg. The chemical composition of coconut husks consists of cellulose, lignin, pyroligneous acid, gas, charcoal, tar, tannin, and potassium.

The predominant use of coconut husks is in direct combustion in order to make charcoal, otherwise husks are simply thrown away. Coconut husk can be transformed into a value-added fuel source which can replace wood and other traditional fuel sources. In terms of the availability and costs of coconut husks, they have good potential for use in power plants.

Top 5 Tips For Reducing Waste in Your Home

Reducing waste in your home is more important now than ever. As the environment is becoming more in danger because of greenhouse gases, climate change, and pollution, the need for humans to reduce their carbon footprint is imperative. However, even if people want to make an effort to save the environment, many people don’t know where to start and how to go about changing their everyday lives in order to become more eco-friendly.

Starting in your home is a great way to begin working towards an eco-friendly lifestyle. A custom home builder in Cherry Hill New Jersey, said, “Making your home environmentally savvy can mean installing something as large as solar panels or it can mean something much smaller; like using reusable shopping bags at the grocery store and not buying plastic products. Either way, making your home eco-friendly is important.”

Reducing waste in your home is easy and will have an outstanding impact on the environment. Here are some quick and easy tips to keep in mind that will help you reduce waste in your home:

1. Start Composting

Starting a compost pile creates less trash by recycling leftover food that would otherwise go in the trash. The point of a compost pile is to put the leftover, and even expired, food back into the earth rather than letting it sit in the garbage or in landfills.

compost_strategies

A compost pile is easy to start, all you need is a bin and some extra space. After you’re done eating something (as long as it isn’t meat, a milk product, or greasy processed food), you can put it in this bin and then incorporate it into your garden or yard every few weeks. Your food won’t go to waste and your garden/yard will get the nutrients it needs.

2. DIY Beauty and Household Products

Buying less plastic products is another great way to reduce waste in your home. However, most beauty and household products are packaged in plastic containers which makes reducing plastic in this way a major obstacle.

A possible solution to this issue is making your own beauty and household products like floor cleaner, deodorant, and toothpaste. Though buying the ingredients to make these products may create a small amount of waste, the ingredients are easier to buy in bulk so you will have to buy them less frequently and will be able to create ample amounts of beauty and household products.

Creating homemade products is also a great way to ensure you aren’t getting chemicals in your products that are damaging to the environment and will create waste or harmful toxins.

3. Meal Plan

Food waste is a huge issue in households. Often, between ¼ to ½  of a household’s weekly produce, meats, and milk products are thrown out at the end of the week. This is preventable with the incorporation of meal planning and meal prepping in your life. By starting a meal plan, you will only buy what you need and will be less likely to waste products because they expired.

food-waste-management

This will generate less waste in terms of food that will end up sitting in a landfill but also in terms of plastic packaging waste that food is packaged in.

4. Repair Instead of Replace

This is an easy way to create little waste in your home that many people don’t think about. When something in your home breaks, whether it is a small kitchen appliance or something large like a heater or part of a couch, take the time to repair it instead of getting a new one. If you repair an item, the original one won’t make its way to a landfill and you will get more life out of your products.

If an appliance or piece of furniture is unable to be repaired, make an effort to recycle some of the important parts; or, if you are in the market to buy a replacement, look online for used products or go to a secondhand store. This will create less waste and will also save you money.

5. Cancel and/or Recycle Junk Mail

Easy and free, by canceling and recycling junk mail will immediately reduce waste in your home. Most people don’t even look at the junk mail and toss it right in the garbage can. Canceling subscriptions only requires a phone call or email and will significantly cut back the waste that is generated in your home.

If you receive junk mail that is not sent to you via subscription and you are unable to cancel it, make sure to at least recycle it.

Eliminating junk mail will also help with decluttering your coffee tables and countertops, an added benefit to helping the environment.

Bottom Line

There is always room for improvement when trying to improve your lifestyle in terms of creating less waste. These tips are a great way to start making an impact on saving the environment before it’s too late. Reduce the waste in your life with minimal effort and small, simple changes.

Solid Wastes in the Middle East

The high rate of population growth, urbanization and economic expansion in the Middle East is not only accelerating consumption rates but also increasing the generation rate of all  sorts of waste. The gross urban waste generation quantity from Middle East countries is estimated at more than 150 million tons annually. Bahrain, Saudi Arabia, UAE, Qatar and Kuwait rank in the top-ten worldwide in terms of per capita solid waste generation. 

Saudi Arabia produces around 15 million tons of garbage each year. With an approximate population of about 28 million, the kingdom produces approximately 1.3 kilograms of waste per person every day.  According to a recent study conducted by Abu Dhabi Center for Waste Management, the amount of waste in UAE totaled 4.892 million tons, with a daily average of 6935 tons in the city of Abu Dhabi, 4118 tons in Al Ain and 2349 tons in the western region. Countries like Kuwait, Bahrain and Qatar have astonishingly high per capita waste generation rate, primarily because of high standard of living and lack of awareness about sustainable waste management practices.

In Middle East countries, huge quantity of sewage sludge is produced on daily basis which presents a serious problem due to its high treatment costs and risk to environment and human health. On an average, the rate of wastewater generation is 80-200 litres per person each day and sewage output is rising by 25 percent every year. According to estimates from the Drainage and Irrigation Department of Dubai Municipality, sewage generation in the Dubai increased from 50,000 m3 per day in 1981 to 400,000 m3 per day in 2006.

Waste-to-Energy Prospects

Municipal solid waste in the Middle East is mainly comprised of organics, paper, glass, plastics, metals, wood etc. Municipal solid waste can be converted into energy by conventional technologies (such as incineration, mass-burn and landfill gas capture) or by modern conversion systems (such as anaerobic digestion, gasification and pyrolysis).

At the landfill sites, the gas produced by the natural decomposition of MSW is collected from the stored material and scrubbed and cleaned before feeding into internal combustion engines or gas turbines to generate heat and power. In addition, the organic fraction of MSW can be anaerobically stabilized in a high-rate digester to obtain biogas for electricity or steam generation.

Anaerobic digestion is the most preferred option to extract energy from sewage, which leads to production of biogas and organic fertilizer. The sewage sludge that remains can be incinerated or gasified/pyrolyzed to produce more energy. In addition, sewage-to-energy processes also facilitate water recycling.

Thus, municipal solid waste can also be efficiently converted into energy and fuels by advanced thermal technologies. Infact, energy recovery from MSW is rapidly gaining worldwide recognition as the 4th R in sustainable waste management system – Reuse, Reduce, Recycle and Recover.

Challenges in Hazardous Medical Waste Management

Medical waste management is a concern of healthcare facilities all over the world; about 10-20% of the facility’s budget every year is spent on waste disposal. According to the WHO, about 85% of the total amount of generated waste is non hazardous but the remaining 15% is considered infectious, toxic or radioactive. While non-hazardous medical waste poses less problems, the risks and challenges of hazardous medical waste management must be considered carefully, since incineration or open burning of hazardous medical waste can result in emissions of dangerous pollutants such as dioxins and furans.

medical-waste-management

For this reason, measures must be taken to ensure safe disposal of hazardous medical waste waste in order to prevent negative impact on the environment or biological hazards, especially in developing countries.

Health Risks

Biologically hazardous waste can be a source of infection due to the harmful microorganisms it contains; the most exposed are hospital patients, hospital staff, health workers. However, the situation is potentially harmful for the general public as well. The risks include chemical burns, air pollution, radiation burns and toxic exposure to harmful pharmaceutical products and substances, such as mercury or dioxins, especially during the process of waste incineration.

Other risks can also derive from the incorrect disposal of needles and syringes; worldwide, it is estimated that, every year, about 16 billion infections are administered. Unfortunately, not all needles are safely eliminated, creating risk of infection but also the possibility of unintentional reuse. Even though this risk has decreased in recent years, unsafe infections are still responsible for many new cases of HIV, hepatitis B and hepatitis C.

Environmental Impacts

Incorrect disposal of untreated healthcare waste can contaminate drinking and ground water in landfill, and also release dangerous chemical substances in the environment. Deficient waste incineration can also release hazardous pollutants in the air, and generate dioxins and furans, substances which have been linked to cancer and other adverse health conditions. Heavy metals, if incinerated, can lead to the diffusion of toxic metals in the environment.

The Way Forward

There is still a long way to go in order to ensure safe disposal of hazardous healthcare waste. A joint WHO/UNICEF assessment conducted in 2015 found that only 58% of analyzed facilities over 24 countries had appropriate medical waste disposal systems in place.

Strategies to improve healthcare waste segregation is an essential step in medical waste management

In the workplace, it is important to raise awareness and promote self-practices. Training in the areas of infection control and clinical waste management is important in order to maintain a clean, safe environment for patients and staff alike. Specialized industrial cleaning can also be effective in reducing risk of infection.

It is also essential to develop safe methods and technologies of treating hazardous medical waste, as opposed to waste incineration, which has already been shown to be ineffective and dangerous. Alternatives to incineration, such as microwaving or autoclaving, greatly reduce the release of hazardous emissions.

Finally, developing global strategies and systems to improve healthcare waste segregation is another essential step; since only about 15% of clinical waste is hazardous, treatment and disposal costs could be reduced significantly with proper segregation practices. Furthermore, these practices also reduce risks of infections for those workers who handle clinical waste.

Is Tire Recycling Dangerous?

Not too long ago, mountains of old tires were to be found in virtually every town and city’s landfill, and toxic tire fires that would sometimes take months to subside were a common occurrence. Today, these tire piles are a rarity, and thankfully, so are the fires that used to go with them.

scrap-tires-pyrolysis

We have largely to thank the combined initiatives of scientists, entrepreneurs, and legislators from banishing unsightly these unsightly tire piles from the landscape. Today you’re more likely to see old tires in your yoga mat or the asphalt you drive on than in ugly piles that you can see from the distance.

However, there have been questions about the widespread use of tire chips, especially in playgrounds, as mulch, and as repurposed water containers for agriculture and livestock.

These concerns are quite understandable, as we are in direct contact with tire chips when they are used in the first two applications. When used for agriculture and livestock, there seems to be a distinct and logical risk that any toxins that are released in those applications may eventually end up in our bodies.

Recycled tire products are safe for consumers

Provided that you are not the one processing the tires yourself (more on that later), there is an extremely low toxicity risk in tire chips. A typical tire chip is made from old tires, which means that they have already off-gassed much of their volatile organic compounds (VOC’s).  New tires emit a good amount of VOC’s, which you can readily detect because of the unique new tire smell.

Many of these compounds have been linked to cancer. However, decades of research and uncontrolled use of old tires in different applications through the 20th century seem to strongly indicate that unless you are actually involved in producing or processing tires, your risks are quite low due to the low dosage of chemicals a typical consumer can expect. It’s the doses that makes a chemical toxic, and in the case of old tires where most tire chips are derived, the risk is negligible.

However, working in an environment where you can actually smell the “new tire scent” constantly can be a significant risk. By analogy, a bartender will be fine if they have a drink with one customer. But if they drink with every single customer that comes by every night, they’re in serious trouble.

Recycling large volumes of tires can be problematic

Unless you constantly work with tires, the risk is quite minimal. You can and should feel free to recycle or repurpose any tires you have around your house or yard into furniture, tire swings, planters, or pet beds. However, if you’re thinking of recycling dozens of tires a week, you should reconsider, as the particulate dust from carving up or shredding old tires can also be a risk over time if you don’t have the right equipment or safety gear.

Improper tire recycling can also heighten your exposure to dangerous chemicals in the tires, especially when they are subjected to the heat of a grinder or shredder that is not specifically meant for tire recycling. This can expose you to high levels of carcinogenic VOCs without you realizing it.

If you need to safely dispose of a high volume of tires, or tires that are difficult to recycle, such as those on tractors and OTR vehicles, be sure to contact a professional recycler like Western Tire Recyclers.

Pet Waste Management in UK – Prospects and Challenges

Pet waste is a growing public health and environmental risk. According to a report commissioned by the Pet Food Manufacturers’ Association, 13 million UK households (45%) keep pets of some kind. Cats and dogs are each kept by 8.5 million households (these numbers are not additive, as some will of course keep both).

pet-wastes

Can those of us who want both the joys of animal companionship and waste minimisation, find ways to cut down, or better manage, the huge amount of pet waste generated in the UK every year? With so many cats and dogs in the UK, pet waste must represent a significant mass of organic matter within the residual waste stream.

Does this waste represent a floater in the residual waste stream by necessity—due to inherently unpleasant and possibly dangerous characteristics of the waste—or is it only there out of convention and squeamishness?

I’ve written before about the relationship between waste management and squeamishness, and talking about faeces really brings the point home. There are some undoubtedly nasty pathogens present in pet faeces, notably the parasites Toxocariasis and Toxoplasmosis. But might these be safely killed off by the temperatures reached in anaerobic digestion (AD). If so, provided any litter and bags were made of organic matter, might pet waste be collected along with food waste?

I began by contacting a local authority waste officer, but was told that no one had asked this question before, and that I might be better off talking to AD plant operators. This I did, but most seemed similarly baffled by my query. However, one mentioned that AD digestate goes through a pasteurisation process, where it is heated to a temperature of 70oC for one hour, in order to make it safe for land application. I also attempted to contact some technical specialists in the field, but to no avail.

There are some theoretical indications that this pasteurisation should be sufficient. Hanna Mizgajska-Wiktor and Shoji Uga’s essay Exposure and Environmental Contamination states: “Anaerobic waste treatment kills Toxocara spp. eggs at temperatures in excess of 45oC”, well below the 70oC mentioned by my operator. The susceptibility of Toxoplasma to heat is less clear, although numerous internet sources suggest this can be killed in meat by cooking at 66oC. So far, then, I haven’t confirmed or falsified my initial inkling, and so the collection of pet waste in the municipal organic stream remains a theoretical possibility.

Motivated dog owners can already turn their pet’s waste into a resource within their own home. The website London Worms explains how you can turn your dog’s poo into rich and useful vermicompost, although it warns that the results will only be suitable for use on non-edible plants.

Foul Pay

Household pet droppings may still be largely fated for disposal, but even when binned this waste is at least moving through proper waste management channels. Unfortunately, not all pet poo is binned, and we have real data measuring public perceptions of the disamenity resulting from dog fouling. For most, the presence of this unwelcome waste in our streets, parks and footpaths is of much higher concern than its diversion from landfill. Therefore, it is necessary to make use of biodegradable dog poop bags to keep our environment clean.

A 2011 Defra-funded study on local residents’ willingness-to-pay — via an increase in council tax — for improvements across a range of environmental factors found that dog fouling was the third most important issue out of the presented range (with litter and fly-tipping taking first and second place). Surveys were conducted in inner-city, suburban and rural/semi-rural areas around London, Manchester and Coventry.

In order to move from the current level of dog fouling to the best possible scenario, it was found that inner-city residents would on average be willing to pay £8.87 per month, suburban residents £7.79 per month, and rural residents £2.72. Combining these figures with population statistics allows us to place a disamenity value on dog fouling. National statistics only allow for an urban-rural split, but based on a 2012 Defra rurality study which found that 18.9% of the population lives in rural areas, we can calculate that across England we would collectively be willing to pay £462m per year to achieve best case scenario improvements in dog fouling.

This somewhat crude calculation gives an indication of the perceived disamenity of dog fouling. Presenting the matter in terms such as these may allow economically minded policy makers a means of engaging with this important street scene issue and evaluating the costs and benefits of interventions.

Food for Thought

Let’s wash our hands of poo (with plenty of soap and warm water) and look to the other end of the pet waste problem. According to a report published by WRAP, the UK uses around 75,000 tonnes of primary packaging annually. This holds 1,263,000 tonnes of wet and dry cat and dog food, of which 9,000 uneaten tonnes are thrown away. Although this wasted food constitutes less than 1% of the total sold (if only we were as careful with food for human consumption) the estimated cost to the consumer is still £21m a year.

WRAP examined a number of designs intended to cut to down on the amounts of both pet food and packaging thrown away. A major problem with packaging design is the need to account for portion sizes, which vary from animal to animal and change depending on age and level of activity. Single serve packaging may actually lead to regular food wastage if the portion provided is too big for a particular pet; indeed, this is a problem I am experiencing with my own cat, whose appetite seems to fluctuate wildly. Re-sealable packaging that allows owners to dish out meals in accordance with the changing appetites of their pets is therefore preferable.

The material that packaging is made of is also significant: for example, relatively heavy tins are recyclable, whereas lightweight plasticised plastic foil packets are not. Pet food and its packaging can be pushed up the waste hierarchy by simply choosing a recyclable and resealable container which will allow them to adequately provide for the appetite of their pet. However, these issues are likely to be given less weight compared with health, convenience and cost in the minds of most householders. The onus has to be on manufacturers to develop packaging which is both low cost and easily recyclable.

Love pets, hate waste?

People love animals, but are rather less keen to engage with pets as an environmental issue. Leaving aside questions of whether it is sustainable for so many of us to have pets at all, there are clearly ways in which we can reduce their impact. The convenience of single serving pouches of pet food seems to win out over more recyclable and waste-avoiding alternatives, although pet owners might be willing to change their choices if presented with a better option.

While worrying about recovery options for cat poo might seem somewhat academic, it may be easier to tackle than dog fouling. It might even help to tackle the common psycho-social root of both issues. Cultural distaste perhaps lies behind the lack of information available on dealing with household pet waste, and the persistence of dog fouling as a street scene issue. Things were very different in Victorian London when “pure finders” earned a living by seeking out doggie doo to supply the tanning trade. But for us this kind of waste is a disagreeable fact of life which we deal with as simply and with as little thought as possible. But as a nation of animal lovers, it’s our responsibility to engage with the waste management issues our pets present.

Note: The article is being republished with the kind permission of our collaborative partner Isonomia. The original article can be viewed at this link

Waste Management in Food Processing Industry

Food processing industry around the world is making serious efforts to minimize by-products, compost organic waste, recycle processing and packaging materials, and save energy and water. The three R’s of waste management – Reduce, Reuse and Recycle – can help food manufacturers in reducing the amount of waste sent to landfill and reusing waste.

EPA’s Food Recovery Hierarchy

EPA’s Food Recovery Hierarchy is an excellent resource to follow for food processors and beverage producers as it provides the guidance to start a program that will provide the most benefits for the environment, society and the food manufacturer.

Notably, landfill is the least favored disposal option for waste generated in food and beverage producers worldwide. There are sustainable, effective and profitable waste management options including:

  • making animal feed,
  • composting to create nutrient-rich fertilizer,
  • anaerobic digestion to produce energy-rich biogas,
  • recycling/reusing waste for utilization by other industries,
  • feeding surplus food to needy people

Waste Management Options

Food manufacturers has a unique problem – excess product usually has a relatively short shelf life while most of the waste is organic in nature. Food waste created during the production process can be turned into animal feed and sold to goat farms, chicken farms etc. As far as WWTP sludge is concerned, top food manufacturers are recycling/reusing it through land application, anaerobic digestion and composting alternatives.

Organic waste at any food processing plant can be composted in a modern in-vessel composting and the resultant fertilizer can be used for in-house landscaping or sold as organic fertilizer as attractive prices.

Another plausible way of managing organic waste at the food manufacturing plant is to biologically degrade it in an anaerobic digester leading to the formation of energy-rich biogas and digestate. Biogas can be used as a heating fuel in the plant itself or converted into electricity by using a CHP unit while digestate can be used as a soil conditioner. Biogas can also be converted into biomethane or bio-CNG for its use as vehicle fuel.

Items such as cardboard, clean plastic, metal and paper are all commodities that can be sold to recyclers Lots of cardboard boxes are used by food manufacturers for supplies which can be broken down into flat pieces and sold to recyclers.

Cardboard boxes can also be reused to temporarily store chip packages before putting them into retail distribution boxes. Packaging can be separated in-house and recovered using “jet shredder” waste technologies which separate film, carton and foodstuffs, all of which can then be recycled separately.

Organizing a Zero-Landfill Program

How do you develop a plan to create a zero-landfill or zero waste program in food and beverage producing company? The best way to begin is to start at a small-level and doing what you can. Perfect those programs and set goals each year to improve. Creation of a core team is an essential step in order to explore different ways to reduce waste, energy and utilities.

Measuring different waste streams and setting a benchmark is the initial step in the zero-landfill program. Once the data has been collected, we should break these numbers down into categories, according to the EPA’s Food Recovery Challenge and identify the potential opportunities.

For example, inorganic materials can be categorized based on their end lives (reuse, recycle or landfill).  The food and beverage industry should perform a waste sort exercise (or dumpster dive) to identify its key streams.

Nestlé USA – A Case Study

In April 2015, Nestlé USA announced all 23 of its facilities were landfill free. As part of its sustainability effort, Nestlé USA is continually looking for new ways to reuse, recycle and recover energy, such as composting, recycling, energy production and the provision of safe products for animal feed, when disposing of manufacturing by-products.

Employees also work to minimize by-products and engage in recycling programs and partnerships with credible waste vendors that dispose of manufacturing by-products in line with Nestlé’s environmental sustainability guidelines and standards. All Nestlé facilities employ ISO 14001-certified environmental management systems to minimize their environmental impact.