What is this tool intended for?

The SIMBA Grow-Out Unit SOP is Designed to guide operators through all daily and weekly tasks required to run the grow-out phase of a small-scale BSF biowaste conversion system. The grow-out unit is the stage where young larvae (7-days-old, or 7-DOL, received from a reproduction unit) are fed organic waste substrate, grown to harvest weight over approximately 10 days, and then separated from the residual frass. The SOP’s purpose is to standardise these operations so that consistent, high-quality larvae and frass can be produced reliably, even by operators with no prior BSF experience, working part-time with simple equipment. It is explicitly Designed for the SIMBA scale: processing around 50 kg of organic waste per week, using 4 incubation containers and 4 grow-out containers, and producing 6–8 kg of fresh larvae and approximately 20 kg of frass weekly.

How does this tool work?

The SOP is a printed or downloadable PDF manual structured into four operational sections:

•        Waste pre-processing: Guidance on receiving and quality-checking biowaste, reducing particle size to below 5 cm, adjusting moisture content (target density 0.8–0.9 kg/L) by adding dry or wet Materials, and storing waste in sealed but ventilated buckets until use.

•        Treatment (grow-out): A strict two-day-per-week Feeding schedule (e.g. Monday and Thursday). On Day 1, 15,000 seven-day-old larvae are placed into a small incubation container (~30×20 cm) with 2 kg of waste substrate. On Day 4, larvae are transferred to a larger grow-out container (~40×60 cm) with 10 kg of substrate. On Day 8, containers are stirred to aerate and prevent overHeating. On Day 11, larvae are harvested.

•        Harvesting: Visual and tactile indicators guide operators to confirm readiness (larvae showing beige-brown colour; dry, dark, crumbly frass). A manual sieve (4 mm mesh) is used to separate larvae, frass, and residue. Expected yield per container is approximately 5–6 kg of combined material per 12 kg of waste substrate and 15,000 larvae.

•        Short-term storage and use: Guidance on storing fresh larvae in dark, ventilated containers with damp sawdust or bran for up to one week; killing and drying larvae for longer storage; and recommended replacement rates when Feeding larvae to chickens, pigs, or fish (up to 20% fresh; up to 5–8% dried).

A monitoring section provides formulas and guidance for calculating waste reduction rate and biomass conversion rate (BCR), with typical BCR benchmarks by substrate type (e.g. food waste: 12–20%; pig manure: 6–14%). An annex provides illustrated descriptions of all required equipment items, including grow-out containers, basins, bioponds, storage buckets, shovels, sieves, and scales.

The SOP is an analogue (PDF) resource. No Software or internet connection is required to follow the procedures. All calculations use simple arithmetic and can be done with a pen and paper or basic calculator.

Who might use this tool and with which types of stakeholders?

The SOP is intended for:

•        Smallholder farmers who want to produce BSF larvae as protein-rich Feed for their own chickens, pigs, or fish, using locally available organic waste as a substrate

•        First-time BSF operators exploring BSF biowaste conversion as a part-time side activity or demonstration project

•        Research centres and universities operating small-scale BSF units for research, training, or demonstration purposes

•        Extension workers and trainers who support farmers or entrepreneurs in setting up and managing BSF grow-out units

•        NGOs and development projects that introduce BSF as a sustainable waste management and livelihood solution at community level

The SOP is written in plain, accessible language and does not assume prior entomological or engineering knowledge. It is directly usable by individual farm workers and operators, and can also be used as a training reference by extension agents or project supervisors.

What stages of a process can this tool support?

The SOP supports the operational implementation stage of a BSF grow-out unit, specifically:

•        Waste pre-processing: Quality control, particle size reduction, moisture adjustment, and storage of biowaste substrate

•        Larval grow-out management: Dosing of larvae and substrate into incubation and grow-out containers, following the two-day-per-week Feeding schedule

•        Harvesting: Identifying harvest readiness, separating larvae from frass using sieving, and weighing fractions

•        Product use and storage: Short-term storage of fresh larvae, killing and drying for longer-term storage, and Feeding to livestock

•        Performance monitoring: Tracking key performance indicators including waste substrate input, larval and frass yields, waste reduction rate, and biomass conversion rate

The SOP assumes that waste sourcing has already been secured and that young larvae (7-DOL) are supplied from a reproduction unit (covered in the companion SIMBA Reproduction Unit SOP). It does not cover facility setup, capital investment, or business planning, which are addressed in the BUGS Africa Operators Toolkit.

What skills, capabilities and resources are required to use this tool?

The SOP is Designed to be accessible without specialist training. Requirements include:

•        Around 4–5 hours per week of worker time across two working days per grow-out unit

•        A responsible manager with a basic understanding of BSF larvae behaviour to oversee operations and respond to deviations

•        Approximately 150 m² of roofed space with protection from sun and rain, subdivided into areas for waste pre-processing (~6 m²), grow-out (~20 m²), and harvesting (~20 m²)

•        Basic equipment items: incubation containers (~30×20 cm), grow-out containers (~40×60 cm or equivalent basins/bioponds), sealed storage buckets, a manual sieve (4 mm mesh), a bulk scale, a shovel or rake, and a spoon for substrate aeration

•        Suitable ambient temperature (ideally 25–32°C) and relative humidity (ideally below 50–70%)

•        A supply of young larvae (7-DOL) from a BSF reproduction unit, and a reliable source of organic biowaste substrate

No internet connection is required to use the SOP. Access to a device for downloading the PDF is sufficient.

Where can this tool be used?

The SOP is applicable in any location where BSF biowaste conversion is feasible, with a preference for tropical and sub-tropical climates where ambient temperatures and humidity naturally support BSF larval growth without additional climate control. It is particularly suited to:

•        Smallholder farms in Sub-Saharan Africa, South and Southeast Asia, and Latin America where locally available organic waste (food waste, market waste, agricultural residues, manure) can serve as substrate

•        Urban and peri-urban community settings where decentralised organic waste treatment is needed

•        Research stations and vocational training centres using BSF as a demonstration or teaching tool

•        Any context where the SIMBA scale (50 kg of waste per week per grow-out unit) is appropriate, and where simple, low-cost equipment is preferred over mechanised alternatives

The SOP is also applicable in higher-income contexts, though it is primarily Designed with low-resource settings in mind. For larger-scale operations (over 150 kg of waste per week per grow-out unit), the SOP includes guidance on scaling up using bioponds or larger containers, and refers users to the Eawag Step-by-Step Guide for medium-scale systems.

Case examples of where this tool has been used

The SIMBA system and its associated SOPs were developed through field experience in the BUGS-AFRICA and SWIFT projects, with partner institutions in Malawi (Soil Food and Healthy Communities/SFHC, Mzuzu University), Uganda (Makerere University, Bioconvision), and across Africa (Africa Circular). Practical testing of the grow-out procedures, container configurations, larval densities, and Feeding schedules described in the SOP drew on operational experience at multiple small-scale BSF facilities in these contexts.

The SOP is also referenced in the BUGS Africa Operators Toolkit (CCAC, 2025) as the recommended standard operating procedure for SIMBA-scale grow-out operations, and is intended to be used alongside the companion Reproduction Unit SOP and the BSFL Substrate Navigator to support a complete small-scale BSF operation.