Business case study

At a glance

Processes around 80,000 tonnes of waste a year
Incoming feedstock is fully processed into renewable energy and fertiliser just three days after entering the system
The plant and offices are run by energy produced on site, with remaining energy fed in to the national grid
In 2016 a second AD tank was completed which increased processing capacity to 100,000 tonnes of waste a year
Own fleet of 30 food waste powered collection vehicles creating a one-stop solution and maintaining a closed loop service for its customers
Focuses on companies within the M25, incurring a lower carbon footprint through reducing food waste travelling miles

Overview

Bio Collectors is the largest recycler and collector of food waste in London. The company’s anaerobic digestion plant is capable of processing 100,000 tonnes of waste every year, which can generate the equivalent of 6mW of gas and 1.7mW of electricity per hour. The company has a variety of customers, including grocery retailers, manufacturers, restaurants, hospitals and local businesses. It operates 30 vehicles that service customers across London, providing flexible bespoke collections as needed. Unlike other AD plants, Bio Collectors is capable of processing biodegradable packaging as well as food, making it a one-stop shop for many customers that do not have the resources to separate packaging on site.

Over the years Bio Collectors invested heavily in maximising the potential of energy from food waste, introducing new technologies and building a second tank that has doubled its capacity. The AD process produces two products: energy and digestate. Firstly, green energy produced is used to run the plant and on-site offices, with the remainder fed back into the national supply. Bio Collectors is the only site in south-east England that injects gas directly into the national grid. Very few sites are able to offer this service due to the complexity of the system and the regulations surrounding it. In order to connect to the National Grid distribution network, Bio Collectors invested in technology to ensure the quality of gas produced met the requirements set out in the Gas Safety (Management) Regulations GS(M)R 1996.

After generating biogas from the food waste it collects, the company’s processes ensure it is upgraded to a higher quality of biomethane for gas injection. The regulations state biomethane must be enriched with propane so that the target calorific values are met where appropriate. The anaerobic digestion plant has also been fitted with telemetric controls allowing it to be remotely monitored 24/7 by DNCC Central Gas Control to ensure strict quality control.

Using food waste, the Bio Collectors site in Mitcham can produce 1000cu/m of biomethane per hour – enough to heat over 6,000 homes per year.

The second product is digestate – a nitrate rich fertiliser that is distributed to local farms. Bio Collectors prides itself on supporting local farmers and promoting the value of a circular economy.

Simon Williams of Trade Effluent, which works with Bio Collectors, collecting the digestate and distributing it across local farms, said: “Digestate that comes from Bio Collectors is an ideal replacement for those expensive chemical fertilisers, and that’s where we fit in. We market those products to the farmers and it closes a loop with the digestion process based on food waste generated by farms, which is then sent back to grow the next season’s crops.

As well as promoting more environmentally-friendly recycling processes, the company also believes it is essential to work with local councils and the government to help businesses and consumers reduce their carbon footprint. A significant amount of food waste collected in London is transported outside the capital for disposal, whether that be via AD or another unsustainable method, such as incineration. Bio Collectors primarily works with businesses based within the M25 in order to maintain low food waste miles and therefore a low carbon footprint to support its green ethos.