So how can we prevent fatbergs?

Eww: a piece of fatberg in the streets beneath London. Image: Getty.

Fatbergs – enormous solid masses of oil, grease, wet wipes and other hygiene products that congeal together to cause major blockages – are wreaking havoc on the sewers of cities around the world. A 130 tonne specimen described as a “monster” recently caused backups in sewers in London’s Whitechapel, and the cities of Baltimore, Singapore and Dannevirke, New Zealand have also all experienced similar issues in recent weeks.

Fatbergs are not a recent phenomenon, but have attracted increased attention in recent years as old sewerage systems struggle to cope with an increased consumption and disposal of everyday products like fats, oils and greases from cooking. This is a particular issue for cities like London with Victorian systems. The visceral disgust that runs alongside the image of fatbergs lingering under the city, and the potential impact they will have on local flooding, means that they will remain a topic that demands attention.

Strategies are already being put in place in order to prevent sewer fatbergs. Current water industry tactics tend to focus on removing sewer blockages and reducing the fats, oils and greases that enter sewers from commercial sources (such as restaurants). But around three quarters of the fats, oils and greases in sewers comes from domestic sources, making household disposal a key priority for change.

Awareness campaigns directed at the public currently focus on what people put down the kitchen sink. Current advice is that cooking fats, oils and greases should be disposed through food or solid waste recycling. But there is little information on how we can dispose of other products – like that fatty off milk at the back of the fridge – without pouring it down the sink. The mucky complexities of how people actually deal with fats, oils and greases in the home suggests that the solution might need to be more complex than awareness campaigns.

In a recent report we suggest that changing people’s broader behaviour related to food waste and disposal of fatty products is not going to be easy to change – and that we also need to look beyond the plughole.

Down the plughole

Fats, oils and greases are changeable, often smelly, visceral materials. The way we dispose of them is tied to attempts to reduce their impact on our kitchens and in our lives, and this becomes entrenched in our everyday habits and routines.

They can be troublesome materials to handle. The fact that they are liquid at cooking temperatures, and often at room temperature, makes them simpler to dispose of via liquid waste than via solid waste channels, yet their tendency to solidify and accumulate in the specific physical and chemical conditions of drains and sewers makes this disposal highly problematic. Fats, oils and greases are not only difficult to deal with, but many also find it unpleasant.

Evidence from research into food waste and disposal suggests that when food begins to deteriorate, its material properties – and the bodily reactions caused by its appearance, smell and feel in the people handling it – play an important role in how it is discarded. The more effectively and reliably it can be sealed off and ejected from the home with minimal human contact, the better.

Our research suggests that if the same is true of householders’ reactions to leftover fats then successful interventions to divert fats, oils and greases from sewers will mean providing an alternative, yet similarly effective, option for quick and seemingly hassle-free disposal than the kitchen sink.

These ideas of disgust, dirt, smell, and convenience are also likely underpinning similar dynamics for the disposal of wetwipes, nappies, and other hygiene products down the toilet rather than the bathroom bin.

Beyond the kitchen sink

But crucially, fats, oils and greases do not end up in our sewers purely due to decisions related to disposal at the kitchen sink. Rather, actions throughout the stages of food provisioning – including shopping, food preparation, cooking, dealing with leftovers, and clearing up – leads to fats, oils and greases entering sewers.

Another way of thinking about the issues is in regards to tracing the numerous decisions that occur in the process of carrying out routine household tasks: moments in which resources are used up and waste is produced. This is broader than just individual behaviours and involves a consideration of all of those moments where waste fat is indirectly or directly produced – such as when we are choosing what to cook; how much oil to use; whether to reuse that rendered meat fat from the Sunday roast in the next meal we cook or discard it.


Insights into what shapes behaviour at these points lead to a range of implications and recommendations for policies and intervention programs. For example, there needs to be a recognition that disposal of products like fats, oils and greases is part of a wider set of kitchen practices that are in turn shaped by wider systems of food provision (supply chains, retail, and so on) as well as waste disposal facilities.

Interventions that influence household behaviour therefore don’t just need to target the household but could involve product innovations that reduce likelihood of excess fat oil and grease production – for example, fryers that use less fat. Retail environments and packaging could be used as means of changing social norms. Sewerage systems could be rethought. Effective alternative waste fat and oil disposal infrastructures could be envisioned.

The ConversationRather than fatbergs just being seen as a water industry issue there needs to be greater collaboration across sectors (water, energy, food) to deal with the problem. Potential solutions need to range from the level of the household right through to new infrastructures that are experimenting with turning this mucky fatberg problem into energy and biofuel.

Alison Browne, Lecturer in Human Geography and the Sustainable Consumption Institute, University of Manchester and Mike Foden, Postdoctoral Research Associate, Keele University.

This article was originally published on The Conversation. Read the original article.

 
 
 
 

Marseille and Paris are crawling with rats. But it’s your problem too

A Parisian rat. Image: Getty.

You can very easily have a fine time in Marseille, but it is likely to be interrupted by rats.

The bloated and brazen beasts are so utterly convinced they own the place that they barely register any human presence to distract from their hedonistic excesses – throwing wild street parties, burrowing holes in overflowing bins, and darting in and out of exclusive harbourfront restaurants. We only really intrude when the occasional, blissfully oblivious rat is splattered across the cobblestones by a scooter.

For many residents, the whiskery foes have gone some way beyond a nuisance to represent a genuine menace. Rats have infested schools and taken over canteens. Pest control services claim they have broken into cars and gnawed through cables, which may have contributed to accidents. It is also alleged that they have caused Internet outages by attacking fibre-optic cables – continuing the venerable horror movie tradition of cutting the power seen in Aliens and Jurassic Park. Rats are also infamous and prolific traffickers of disease and have raised the threat of Leptospirosis.

Rat populations are fiendishly difficult to quantify, given their nocturnal lifestyle and that many live off-grid in the sewers; but by some estimates they now outnumber Marseille’s human inhabitants. Distress calls from the public to the city’s sanitation department and pest control services have increased, and the unofficial fifth emergency service has expanded its operations in response, laying poison traps and sweeping the gutters.

Several factors have contributed to the rat supremacy. Marseille’s Mediterranean climate has always been hospitable to rats, and a series of unusually warm summers – often passing 30°C – have made it more so. (Rats tend to stop breeding when it’s cold.)

City officials also bemoan the wanton waste disposal habits of their citizens, which have allowed large and easily accessible piles of appetising trash to accumulate. Marseille’s councillor for hygiene Monique Daubet recently complained the city has become a “five-star restaurant for rats”.

Others have suggested a series of strikes by garbage collectors gave the rat population a turbo charge it barely needed. A single pair of brown rats can spawn more than a thousand descendants within a year.

That formidable birth rate is one indicator of what the city is up against: the urban rat is almost a perfect predator. Millennia of human ingenuity has failed to remove them from our midst or negate the threats they pose. Rats are supreme survivors – scientists marvel at their survival on nuclear test sites – and they thrive in the most inhospitable environments. They can eat practically anything, but are neophobic, meaning they shy away from all but the most devious poison traps. The rodents are intelligent, resilient, and their ability to colonise new habitats rivals our own.

Faced with this adversary, the local authority has assigned more resources to the fight, through both the city’s sanitation department and the private extermination service A3DS. Both are reluctant to discuss their tactics and whether they are having an impact. But officials are also taking a tough line on public responsibility, insisting that residents dispose of trash after 7pm in sealed bags or face fines. The city has also proposed measures such as mobile dumps and new model bins that rats should find harder to access.

The Marseillais are also keeping a close eye on events in the capital: Paris’ rat problem may be even more severe, driven by flooding from the River Seine that has forced the rodents to seek higher ground. In recent years, rats have overrun the Louvre and forced the closure of public parks, as well as starring in viral video nasties that do little for the city’s image as the capital of romance.


Paris mayor Anne Hidalgo has sounded the alarm and invested millions of euros in a campaign against rats, which has seen thousands of raids in hundreds of parks and buildings, as well as the introduction of more secure bins, and fines levied against people accused of feeding the enemy. Her administration has also despatched an envoy to New York to study the city’s approach to its own notorious rodent community.

An international approach makes sense given that rats are on the march all around the world. Reported sightings have shot up in New York, Chicago, Boston, San Francisco, and Washington. One study estimated that rats inflict $19 billion of economic damage each year in the US alone. London has also seen an increase in reported sightings. Leading rodentologist Bobby Corrigan says the same patterns are playing out in the major cities of the Americas, Europe, Asia, and Australia.

And for much the same reasons. Contributing factors include “too few resources allocated an organised program for rat control,” says Corrigan. “Also, more people in our cities means more refuse, more overloading of the city’s sanitation budgets, less thorough removal of the kind of food shrapnel that escapes typical garbage collection. Each rat only needs about 30 grams of food per 24 hours to thrive and reproduce.” A warming climate also plays a part.

Poison traps and culls can only go so far, says the rodentologist, arguing that a holistic approach is required to head off the growing threat. “The best measure is a city organised in addressing the rats across all agencies,” says Corrigan. That means mobilising departments of sanitation, parks, housing, health, and sewers, as well as mayoral administrations themselves.

Society-wide civic participation is also essential. “Controlling rats takes everyone: every homeowner, shop owner, restaurant, grocery store, airport, and so on. Not to do so invites the risk of a “new and/or highly virulent virus” developing among our old enemies, he adds.

Research into sterilisation programmes offers some hope of a new weapon to repel and reduce the rodent hordes. But not enough for us to evade responsibility while rat populations grow and the threat increases. “If we don’t work together as the wise species we claim to be and present a scientific, multi-faceted organised effort against this very smart and organised smaller mammal, we can have no hope of defeating it,” says Corrigan. Time to man the barricades.