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Waste treatment via Hydrothermal Carbonisation

There is growing interest in Hydrothermal Carbonisation (HTC), a process that is capable of converting biomass (plant- and animal-based matter) into carbon-rich substances in the presence of water. This means that high moisture content feedstocks can be processed without the need for pre-drying, which can requires large amounts of energy. So think vegetable wastes, agricultural residues, animal litter and sewage into value-added products like catalysts, biofuels, soil enhancers, and environmental remediation products. A video of this process  can be found here
In 2011, HTC was also one of the treatment processes considered for the treatment of waste from modern, lower-flush toilets at Loughborough university, as part of the Bill and Melinda Gates Foundation's "Reinventing the Toilet Challenge".
Can this process be scaled up to industrial level, particularly in developing countries which need sustainable and affordable waste management strategies? That's what I'…

City waste disposal/treatment

As municipal solid waste quantities and treatment costs increase, cities in some developing countries have formed collaborations with various stakeholders to deliver bespoke waste management services.

A lot of thought goes into executing a city’s waste disposal and treatment systems, with cost understandably being a crucial factor. For instance, cost determines manpower, number/type of trucks to use, timing and frequency of collection, location of treatment facilities, and many other considerations that have been elaborated on here. The nature of the city also adds a level of complexity to the waste collection/treatment equation. In an earlier post, waste collection in the Northern English city of Leeds was compared to that of the North-Central Nigerian city of Jos. The well-developed road networks in the Leeds city example allow for easier bulk residential waste collection. Conversely, waste collection in densely populated residential areas with small in-roads as found in many Nigeri…

Waste Collection: 'A Tale of Two Cities'

Waste management systems in many developing countries has much room for improvement. Some positive changes are outlined in the second section of this article.

Somewhere in Europe...
It’s Saturday, 8.45am in a quiet residential area of Leeds, UK. The distinct beep-beep-beep of a garbage collection truck is within earshot. In just a few more minutes, three experienced collectors will haul grey wheelie bins filled with rubbish into this truck. For efficient weekly rubbish collection, all the collectors ask of residents is to make sure they wheel out their grey bins to the kerbside before the truck arrives. All over-18 year old residents of the neighbourhood, with the exception of full-time students, pay for this service. Payments are made to the local city council government as council tax, property fees which also provide funding for other city sanitation as well as recreational services. For residents, the waste disposal cycle is now complete: from 'Household Bin' to 'Large…

Using waste to treat waste: Landfill leachate & biochar?

Waste companies use different strategies to handle landfill leachate, the unpleasant cocktail produced by waste in landfills. A relatively new strategy involving waste-based adsorbents joins the mix.
Until fairly recently, landfills have been our go-to solid waste disposal method. These days however, there is growing interest in identifying practical and cost-effective ways to minimise the amount of waste going into landfills or open dumpsites– preference is given to waste recycling or valorisation (i.e, turning waste into a resource). Many of us already do this on a small scale, when we choose to DIY our own compost. Or transform this afternoon’s roast turkey into tomorrow’s sandwich filler. Or reuse our shopping bags. Or use clear beer bottles as peanut containers, as is often the case in Nigeria. On a larger scale, many countries are thinking hard about sustainable waste management. For example, an old pair of trousers has potential to be more than landfill material; it can be a sou…