From restaurant waste to animal feed in six days

There is no smell. In flat plastic trays, sixty by forty centimetres, millions of black soldier fly larvae burrow through a moist beige mash of shredded bread, yeast and sawdust. They are five days old, the size of a fingernail, cream-coloured, a pulsating mass: Hermetia illucens. Tina Kusumawardhani, plant manager at Bioconvision in Wakitaka, lifts a tray, holds it up to the light and invites us to reach in. It tingles. Nothing else.

The facility at Wakitaka, some five kilometres outside Jinja, once Uganda’s industrial centre at the source of the Nile, with a tradition of brewing and sugar, today home to nearly 300,000 people, is the breeding station of a transnational research project with the somewhat unwieldy name SWIFT, Sustainable Waste-based Insect Farming Technologies. Funded through the Swiss programme Solution-oriented Research for Development (SOR4D), jointly run by the Swiss Agency for Development and Cooperation (SDC) and the Swiss National Science Foundation (SNSF), the project is exploring whether insect-based biowaste processing in East Africa can be standardised to the point of being economically viable.

It is the 5th of March 2026, a morning with heavy tropical rain. A delegation from SDC and SNSF has come to visit the project that the two Swiss institutions have funded since 2023. In fine-mesh cages nearby, adult flies sit motionless on the walls, almost listless. “They are just sitting around because it is cold,” Tina says. They need warmth and light to become active, and today they have neither.

“Love cages” the consortium calls them, because the black soldier fly mates only in sunlight: emerging flies are lured by light out of a darkened pupation container into a brightly lit cage, where they pair. This allows the breeding cycle to be planned to the day. “An adult Hermetia illucens has nine days to live. In that time it has to mate, lay eggs and die. Anything more is not part of the design,” says Daniela Peguero, environmental engineer at Eawag in Dübendorf and coordinator of SWIFT. She has travelled with us to Jinja and knows almost every cage here.

A production chain in six days

The procedure is simple. A tonne of organic waste (restaurant leftovers, market produce, fish offal from a nearby factory) arrives, is shredded, homogenised with sawdust as a drying agent and spread into shallow basins. Each tonne is seeded with one to one-and-a-half million larvae. Six days later, in the ideal case, what remains is a dark, crumbly substrate (“frass” in the jargon, larval excrement that works as fertiliser), together with a biomass of fat larvae, which are dried, milled or fed live to chickens, pigs and fish. And none of it smells: the larvae process the waste so quickly that anaerobic decomposition, the source of the classic stench of rotting refuse, never sets in.

Konstantin von Hoerner, director of the Ugandan Bioconvision subsidiary, walks us through the stations: shredder, mixer, weighing station, treatment hall, harvesting machine. The harvester is a repurposed gravel-screening rig from the construction trade. The company already holds a fertiliser certification from the Ministry of Agriculture; certification for animal feed is in progress.

From pilot plant to commercial operation

The SWIFT consortium brings together Eawag, Makerere University in Kampala, Mzuzu University in Malawi, the Ugandan company Bioconvision and the Malawian NGO Soil, Food and Healthy Communities (SFHC) – funded by the Swiss programme SOR4D, jointly carried by SDC and SNSF.

Christian Zurbrügg from Eawag’s Sandec department is considered one of the pioneers of black soldier fly (BSF) research in the Global South. The procedure now running commercially in Jinja goes back to an Eawag pilot plant in the Indonesian town of Sidoarjo; the Step-by-Step Guide that emerged there in 2017 is today the most important practical manual for BSF biowaste processing in this region. Tina Kusumawardhani worked from 2019 to 2021 in Indonesia at Eawag’s predecessor project; she now runs the breeding facility in Wakitaka.

What stands in Jinja today translates those preparatory efforts into a commercial operation. SWIFT is now examining under what conditions the procedure becomes a business model.

In search of the right substrate

A team at Makerere University in Kampala has captured an answer in an assessment matrix. Isaac Rubagumya, an agricultural economist, has mapped Jinja’s biowaste streams: markets, hotels, the brewery, fish processing. In Uganda, between 60 and 70 per cent of urban solid waste is organic; for Jinja, Rubagumya’s team arrives at roughly 55 tonnes of usable biowaste per day. On this basis he has developed an assessment matrix that assigns each substrate two values: processing suitability and financial viability.

Two findings stand out. First the water hyacinth, an invasive South American plant that has burdened Lake Victoria for decades: it smothers bays, hampers shipping and fishing. As a large-volume local resource, it would lend itself naturally to BSF processing. The matrix shows otherwise: as a sole substrate it fails, because BSF larvae need nutrient-rich feed with protein, starch and fat, while the water hyacinth is water-rich, fibre-rich and nutrient-poor. As a twenty-per-cent admixture to nutrient-dense food waste, however, it works well: the combination yields a balanced larval diet in which the hyacinth can be processed in large quantities.

Second, rumen waste from abattoirs: nutrient-rich, available in large quantities, and, as a residue of the meat industry, a classic BSF substrate. In Uganda, the Animal Feeds Act of 2024 excludes it as a feed component. The consortium advised parliament during the legislative revision; some suggestions were taken up, the rumen ban remained. An important substrate source thus falls away for Bioconvision. This is the unspectacular side of research: policy advice, data collection, stakeholder analyses, a mapping by power and influence that Florence Lwiza from the Makerere team plots on two axes. On the high-power, high-influence axis sit the ministries of agriculture and environment, the National Bureau of Standards, local authorities. That is exactly where one has to engage, Lwiza says, when the next revision of Ugandan fertiliser policy comes up in a few years’ time.

Malawi: a different situation, a different solution

In Malawi the situation is worse, and more urgent. Roughly 40 per cent of agricultural soils are considered degraded; estimates suggest the country loses more than two million tonnes of maize, its staple food, each year as a result. Synthetic fertiliser has become unaffordable for smallholders. Frank Mnthambala from Mzuzu University shows maps of biowaste sources around Mzuzu City: plenty of market waste, plenty of rumen from abattoirs, hardly any centralised logistics.

Above all, what is missing is everything around it: no standards, no specific policy for insect feed, no bank credit. “When you go to the bank, the banks are not even aware that black soldier fly farming exists,” Mnthambala says. To them, it is a high-risk business, so they cannot finance it. Mnthambala’s team at Mzuzu University has therefore developed a radically simplified procedure, the Simplified BSF Approach (SIMBA), which SFHC applies together with associated smallholders: no light management, no optimised breeding cycles, just two days of work per week at two to three hours a day, but reproducible and cheap.

Rowland Mhone of SFHC shows what this looks like in practice. With 24 associated smallholders across three areas, the NGO runs a decentralised network: it distributes seven-day-old larvae, the smallholders raise them on pig manure and restaurant waste in a 70 to 30 ratio, and feed them to their own chickens. The result: broilers reach slaughter weight in four weeks instead of six. Heavy rainfall recently destroyed two facilities; at one site the smallholders abandoned the fly-keeping operation due to ant infestations and now limit themselves to larvae-rearing.

This is where the break between the two sites becomes tangible. Bioconvision in Uganda targets urban industrial scale: shredders and harvesting machines, certified bags of fertiliser, large customers. SFHC in Malawi targets subsistence and intermediate steps: seven-day-old larvae are distributed to associated smallholders, who use them to treat their own pig manure and feed the larvae to their own chickens.

A calculation in tonnes and margins

We drive twenty minutes to Mafubira, a northern suburb of Jinja, where Bioconvision’s actual processing site is located. Three greenhouses lined up in a row, each containing several rectangular basins, four by four metres, made of concrete, each labelled with a chalkboard: start date, substrate composition in per cent, charge weight in kilograms. One of them shows this mixture: 85 per cent food waste, 10 per cent fish guts, 5 per cent sawdust.

Von Hoerner does the maths. One treatment hall handles 2.5 tonnes of waste per day; three halls are in operation, with room for four more. At full capacity of seven halls, up to 19 tonnes per day would be possible; the realistic planning target is 5,000 tonnes per year. That corresponds to roughly a quarter of the biowaste streams identified by Rubagumya’s team. The gross margin on a kilogram of fresh larvae is around 60 per cent, three to four times higher than on the dried variant.

Bioconvision is nevertheless not yet profitable. The initial investment, around 400,000 US dollars including land, still has to be recovered. Each kilogram sold yields a positive contribution margin, von Hoerner says; his biggest worry is simply to sell more kilograms. From about 300 to 400 kilograms per day, he estimates, the calculation works out.

His word choice gives away his background. Before he started the Bioconvision subsidiary in Jinja in May 2023, von Hoerner had spent ten years in Private Wealth Management at Credit Suisse in Zurich, advising wealthy families and setting up philanthropic foundations. The step from Zurich’s Bahnhofstrasse to an East African insect farm becomes more comprehensible when one learns that his wife Sheila was born in Jinja and that her family comes from the town; Bioconvision Uganda is run by the two of them together. What remains is a banker’s view of a larval farm: cashflow, scaling, annual closings, now applied to a larval farm.

Larvae for international cooperation

SWIFT meets two of the four development goals of Switzerland’s International Cooperation Strategy 2025–2028: economic development through income for smallholders and small and medium-sized enterprises (SMEs), climate and environmental impact through circular economy. Indirectly it touches on food security: cheaper and locally available animal feed could ease the production of animal proteins.

As for research itself, the consortium already has something to show. In September 2024, Eawag and all consortium partners jointly published a Feasibility Assessment Approach, a methodological framework with which any region can be assessed for whether BSF biowaste processing might be economically viable there.

Mzuzu University has documented the simplified SIMBA procedure in two published standard protocols. Rubagumya’s substrate matrix links biological data on larval development, local waste volumes, logistical costs and regulatory constraints; only in combination does this yield knowledge that can be transferred beyond a single site. What is being built here is not only a pilot operation but a methodological repertoire that others can adapt. Bioconvision shares all of its operational know-how openly. “Our competitors are not other BSF farms,” says von Hoerner. “Our competitors are fishmeal and soybean meal.”

At pilot scale the technology works, and the research has influenced political processes. Whether the markets will carry it, and whether a research project with two pilot sites turns into a self-sustaining sector, is the task of the next project phase.