Sandec: Department of Sanitation, Water and Solid Waste for Development
Black Soldier Fly Biowaste Processing
Black Soldier Fly Biowaste Processing 1
A Step-by-Step Guide
Publisher: Eawag – Swiss Federal Institute of Aquatic Science and Technology
Department of Sanitation, Water and Solid Waste for Development (Sandec)
Überlandstrasse 133, 8600 Dübendorf, Switzerland
Phone +41 58 765 52 86
Cover picture: Sirajuddin Kurniawan
Photos: Eawag (unless stated otherwise)
Layout: Leanza Mediaproduktion GmbH
Figures: Stefan Diener, Eawag
Editing: Paul Donahue
Review: Moritz Gold
Circulation: 200 copies printed on original recycled paper
Bibliographic reference: Dortmans B.M.A., Diener S., Verstappen B.M.,
Zurbrügg C. (2017)
Black Soldier Fly Biowaste Processing - A Step-by-Step Guide Eawag: Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland
The content of this document is licensed under a Creative Commons Attribution 4.0 International license
4 Black Soldier Fly Biowaste Processing
Black Soldier Fly Biowaste Processing
A Step-by-Step Guide
Bram Dortmans Stefan Diener Bart Verstappen Christian Zurbrügg
Written and published with financial support from the Swiss Agency for Development and Cooperation (SDC) and the Swiss State Secretariat for Economic Affairs (SECO)
Black Soldier Fly Biowaste Processing I
Black Soldier Fly Biowaste Processing
Table of contents:
Chapter 1: RATIONALE 1
General Introduction 1
Scope and target audience 2
Navigating through this guide 3
Chapter 2: WASTE TREATMENT BY BSF 6
Understanding the natural BSF life cycle 6
Overall siting consideration for a BSF processing facility 8
Engineering the BSF life cycle 10
Chapter 3: ACTIVITIES IN A BSF PROCESSING FACILITY 22
Activities in the BSF rearing unit 22
Activities in the waste receiving and pre-processing unit 44
Activities in the BSF waste treatment unit 48
Activities in the product harvesting unit 50
Activities in the post-treatment unit (larvae refining and residue processing) 54
Chapter 4: HANDLING SCHEDULES IN A BSF-PROCESSING FACILITY 56
Chapter 5: BLUE PRINTS OF EQUIPMENT 79
Chapter 6: MATERIAL REQUIRED IN A BSF PROCESSING FACILITY 84
Material for the BSF rearing unit 84
Material for the BSF waste processing unit 85
5-DOL: Abbreviation for Five-Day-Old-Larvae. Keeping the hatchlings in a controlled and protected environment for five days after hatching increases the survival rate and allows the larvae to be counted before they are added to the biowaste.
Adult: The final development stage after pupation. With insects, this is usually called “imago”.
Anaerobic digestion: Degradation of organic compounds by microorganisms in the absence of oxygen, leading to the production of biogas.
Ant trap: Protects from ant invasion. Each table leg is placed into a container filled with water and a drop of detergent. The detergent reduces the surface tension of the water.
Attractant: Smelly liquid substance that attracts BSF females to lay eggs nearby. Usually, this contains different smelly substances like fermenting fruit, dead flies or residue. BSF eggs have also been found to act as an attractant. It is, therefore, advisable not to harvest eggs every day as the already laid eggs attract other females.
Batch operation: In batch operation, a defined amount of waste and larvae are added to a container, which is harvested after a certain time. Batch operation is in contrast to continuous operation, where waste and larvae are added continuously to the same container. The container is only emptied once it is full.
Biowaste: Generally, all biodegradable matter. In this particular context, it does not include waste high in cellulose (e.g. garden waste, wood, grass clippings, leaves, etc.) as this cannot be easily digested by the larvae.
BSF: Black soldier fly, Hermetia illucens
Coco peat: The powdery material resulting from processing coconut fibre. In this context, it is mostly used for its moisture absorbing properties. It can be replaced by other materials with similar moisture absorbing properties, such as wheat bran, for example.
Compost: Organic matter that has been degraded and transformed by aerobic processes to a soil-like substance and can be used as a fertilizer and soil amendment.
Dark cage: Adult flies emerge in the dark cage where they remain until transferred to the love cage. The darkness keeps the flies calm and prevents mating activity.
Date code: The date code allows for calculating the duration of the ongoing process and is applied to cages and containers. It consists of the calendar week of the year and the day of the week (for example: Tuesday of week 8 is coded as 8.2).
Dry matter: The mass of the matter after all water has been removed. It is usually determined by keeping a sample in an oven at 105°C for at least 12 hours.
Egg: A female fly lays between 400 and 800 eggs from which young larvae will hatch within four days. One egg weighs about 25µg.
Eggie: The media used in an engineered BSF-system to collect eggs. It provides sheltered cavities for egg deposition.
Emerging: When adult flies emerge from a pupa after pupation.
Engineered biosystem: A biological process that has been optimised for a practical use.
Faecal sludge: A waste product from onsite sanitation systems, such as pit latrines or septic tanks. It is usually a combination of excreta and water, often mixed with sand and household trash.
Feeding station: A designated area where waste is added to the larveros. It is advisable that it can be cleaned easily (tiled or sealed floor) as biowaste may be spilled during the feeding operation.
Fishmeal: Fishmeal is a nutrient-rich feed ingredient used in the diets of farmed animals. It is manufactured from wild-caught small marine fish and
is a powder obtained after grinding, cooking and defatting the fish. Fishmeal production is a significant contributor to over-fishing.
Food and restaurant Biowaste from restaurants consists of kitchen scraps and food
waste: waste. It typically has a higher nutritional value and a lower water content than market waste or food processing waste.
Food processing waste: Biowaste from the food processing industry. It varies from fruit and vegetable bits to bread crumbs and/or dairy products. It is usually a homogenous and uniform waste source.
Hammer mill: Crushes and shreds material into smaller pieces by repeated strikes of small hammers. It does not cut material. The particle size is defined by the diameter of the outlet screen.
Hatching: The process of young larvae (hatchlings) emerging from the egg.
Hatchling: Larvae that have just hatched from the eggs. Sometimes also called “neonates”.
Hatchling container: Hatchlings fall into the hatchling container after hatching where they remain and feed for five days on nutritious feed (chicken feed) to become 5-DOL.
Hatchling shower: Harvested eggies are placed on a rack called a hatchling shower, which is placed over a hatchling container. When young larvae hatch, they fall into the hatchling container, which is replaced regularly (every one to three days).
Human faeces: Excrement that is not mixed with urine or water. A product from urine-diverting dry toilets.
Lab oven: An oven which provides a uniform temperature. In BSF biowaste processing, it is mostly used to obtain dry matter samples from waste, residue and larvae, and operates at 105°C.
Larva: The juvenile stadium of holometabolous insects. There are seven larval stages, so-called instars, in the life cycle of the black soldier fly before metamorphosis (transforming them into an adult fly).
Larvero: The larvero is the container where larvae feed on biowaste. It can be of any form, from a standard crate (60x40x15cm) to a pallet sized bin, and up to large concrete basins.
Love cage: The love cage is a netted enclosure with a cohort of same-aged flies received from the dark cages. In the love cage, adult flies mate and females lay their eggs into eggies. After a week, the love cage is removed and emptied.
Low- and middle- Although BSF biowaste treatment can be applied all around the
income setting: globe, the set-up and operation presented in this book focuses on low- and middle-income countries (GNI up to ±10,000 EUR). This context is characterized by low labour costs, and a high organic fraction of the municipal solid waste.
Market waste: Consists mostly of fruits and vegetables. It has a high water content (up to 95%) and is subject to seasonal variation. The outer parts of leafy vegetables may have been exposed to pesticides.
Municipal organic Waste generated by settlements, which includes households,
waste: commercial and industrial premises, institutions (schools, health care centres, prisons, etc.) and public spaces (streets, bus stops, parks and gardens).
Nursery container: In the nursery container, 5-DOL are fed a defined amount of nutritious feed (e.g. wet chicken feed) until they transform into prepupae.
These are used to maintain the colony, which are transferred to the pupation containers where the prepupae pupate and eventually emerge as adults.
Pelletiser: Equipment that molds larvae and other feed ingredients (soymeal, corn, rice husks, etc.) into feed pellets for fish or chicken.
Poultry manure: Manure from broiler production or layer hens. BSF larvae grow well on this rather homogenous biowaste, but tend to remain quite small. This substance is rather dry and may, thus, be used in combination with fruit and vegetable waste.
Prepupa: The last larval stage that crawls out of the waste to search a dry pupation site. In comparison to the larvae, prepupae have a higher chitin content and are, therefore, less easy for fish and chicken to digest.
Pupa: During pupation, the metamorphosis from larva to adult fly happens. Black soldier fly larvae pupate within their last larval skin and pupation lasts around 20 days.
Pupation container: The pupation container is filled with a moist pupation substrate (e.g. compost, moist coco peat, pot soil, etc.) which prepupae bury into and is where they pupate.
Rearing: The rearing facility contains the whole life cycle of the black soldier fly and produces the 5-DOL sufficient to treat the incoming biowaste.
Residue: The leftovers after the treatment process. This substance can be a crumbly, soil-like substrate or a wet slurry.
Shaking sieve: A sieve which vibrates or shakes, that is powered by an eccentric drive. It is used with a mesh 3 to 5 mm in size during harvest to separate grown larvae from the residue.
Slaughterhouse waste: It includes bones, organs, hooves, blood and other inedible animal parts leftover after all the edible parts of the animal have been removed. It can also include the gut content of the slaughtered animals.
Spent grains: The main waste product from beer production. The leftover malt and adjuncts after the mash has extracted most of the sugars, proteins, and nutrients.
Transfer container: Collects the prepupae which crawl out of the nursery container. It contains coco peat or another dry substance to prevent the prepupae from escaping.
Ventilation frame: Provides a space between the layers of larveros. It ensures the exchange of air and, thus, the removal of moisture from the larveros Waste reduction: The waste reduction is measured, either based on wet weight or dry weight, and compares the biowaste going into the treatment with the remaining biomass (residue). Depending on the type of biowaste, one can expect a waste reduction between 60% and 85% dry weight
Waste sourcing: Proper waste sourcing is of crucial importance for a complete waste treatment chain. It relies on a well-organised collection scheme that takes into account efficient collection routes and adequate means of transport. When dealing with municipal solid waste, a special focus needs to be set on the segregation of the organic fraction.
Water content: When a sample (waste, larvae, residue, etc.) is dried at 105°C in a lab oven, all the water that is evaporated is referred to as “water content”. Together with the remaining solids (“total solids”), both are expressed as percentages of wet weight; it equals to 100%
Black Soldier Fly Biowaste Processing
Urban solid waste management is considered one of the most immediate and serious environmental problems confronting urban governments in low- and middle-income countries. The severity of this challenge will increase in the future given the trends of rapid urbanisation and growth in urban population. Due to growing public pressure and environmental concerns, waste experts worldwide are being called upon to develop more sustainable methods of dealing with municipal waste that embrace the concept of a circular economy.
Recycling organic waste material (biowaste) is still fairly limited, especially in low- and middle-in-come settings, although this is by far the largest fraction of all generated municipal waste. This book deals with urban organic municipal waste from households, commercial activities, and institutions. It describes the fairly novel approach of biowaste conversion by insect larvae, using the example of the Black Soldier Fly (BSF), Hermetia illucens, an approach that has obtained much attention in the past decade. Its popularity links to the promising opportunities of using the harvested BSF larvae as a source of protein for animal feed, thus, providing a valuable alternative to conventional feed. Enterprises and small entrepreneurs are already investing significant amounts of money into this technology and are interested in keeping a competitive edge on the practical aspects of operating such a facility in a cost effective way. Although academic publications on BSF are on the increase, the business interest and perceived need to maintain a competitive edge has hindered open exchange about and discussion of the practical day-to-day working steps required to operate such a facility. Filling this gap is the main objective of this publication.
This document is based largely on the experience of a one ton of waste per day treatment facility in Indonesia that has been in operation for over two years and an experimental facility in Sweden in operation for one year. Waste processed at the facility in Indonesia was mostly fruit and vegetable waste from a wholesale market. Upscaling or transferring this information to a larger facility might require some adaptation or adjustment of equipment. It is, however, our opinion that the standard procedures described are valid for a large range of scaling-up.
Several key attributes make BSF technology an attractive treatment option for biowaste from the perspective of waste managers and businesses:
Waste biomass is converted into larvae and residue. The larvae consist of ±35% protein and
±30% crude fat. This insect protein is of high quality and is an important feed resource for chicken and fish farmers. Feed trials have confirmed it as being a suitable alternative to fish meal.
Feeding waste to larvae has been shown to inactivate disease transmitting bacteria, such as Salmonella spp. This implies that the risk of disease transmission between animals and between animals and humans is reduced when using this technology at farm level or when treating waste of animal origin in general (e.g. chicken manure or slaughterhouse waste). However, risk reduction is achieved mainly through material reduction (±80%) rather than through pathogen inactivation.
Waste reduction of up to 80% on wet weight basis has been demonstrated. If treatment is applied at the source of biowaste generation, the costs for waste transport and space requirements for landfills can, thus, be reduced drastically. Such organic waste treatment could furthermore reduce open dumping, which is still an unfortunate reality in low- and middle-income settings.
The residue, a substance similar to compost, contains nutrients and organic matter and, when used in agriculture, helps to reduce soil depletion.
A high waste-to-biomass conversion rate of up to 25% on wet weight basis has been demonstrated, which is a satisfactory output quantity from a business perspective.
There is no need for sophisticated high-end technology to operate such a facility. Therefore, it is suitable for low-income settings that rely mostly on simple technology and unskilled labour.
Two research projects provided the basis for the writing of these guidelines. FORWARD is a four-year applied research project, focusing on integrated strategies and technologies for the management of municipal organic solid waste in medium-sized cities of Indonesia. Among other activities, the project designed, implemented and operated a pilot-scale BSF waste treatment facility at a local wholesale market. The BSF facility was designed to act as a testing and showcase site at which “Standard Operating Procedures” could be determined for further dissemination. FORWARD is an independent non-profit R&D project, funded by SECO, the Swiss State Secretariat for Economic Affairs, under a framework agreement with the Indonesian Ministry of Public Works & Housing (PU-PeRa).
The SPROUT project is a three-year project geared towards developing waste-to-value treatment with the Black Soldier Fly (BSF) larvae. It focuses on hygienic aspects, design and operation of treatment units, quality of products (feed and fertilizer), post-harvest processing regarding feed quality and product safety, business models for BSF waste processing, and evaluation of the environmental impact of BSF waste processing compared to other biological treatment options. SPROUT is a multi-national project, and SLU (Swedish University of Agricultural Sciences) and Eawag (Swiss Federal Institute of Aquatic Science and Technology) are the main research partners and Pacovis AG from Switzerland is the partner from industry. It is funded by the EU-pro-gram ECO-INNOVERA, the Swedish Research Council Formas, the Swiss Federal Office for the Environment FOEN and Pacovis AG.
This manual was written as open source with the ambition that BSF treatment would obtain widespread notice, implementation and replication. In this spirit, the authors would like to acknowledge all those that helped to develop, document and discuss the practical aspects of BSF rearing and waste treatment by larvae. Particular thanks go to Sirajuddin Kurniawan, whose pictures of the equipment and work steps saved us many pages of explanatory text, Cecilia Lalander and Björn Vinnerås of the Swedish Agricultural University SLU (Sweden) for an excellent research partnership, Longyu Zheng and Jibin Zhang of the Huazhong Agricultural University (China) and Michael Wu of JM Green (China) for their openness and their fruitful input, and Puspa Agro for their hospitality.
Scope and target audience
An engineered BSF processing facility can be designed and operated to achieve certain target objectives based on the natural life cycle of BSF. These, for instance, can be to cost effectively augment larvae quality or maximize the larval mass quantity produced within a certain time frame or based on a particular feedstock, similar to a typical livestock rearing system (chicken, beef, etc.).
In this manual, however, we follow a waste management perspective. In other words, we start from the premise that biowaste is the substance of concern for which we suggest to use the BSF treatment technology as a suitable processing and recycling solution to produce larvae and waste residue.
Black Soldier Fly Biowaste Processing
The primary goal, therefore, is to process biowaste in an efficient way with regard to investment and operational costs, as well as space requirements. By processing biowaste, threats to public health and the environment can be reduced.
The technology solution consists of feeding segregated biowaste to BSF larvae, which have been reared in a nursery. Larvae grow on the waste feedstock and reduce the waste mass. At the end of the process, larvae are harvested and, if necessary, post-processed into a suitable animal feed product. The waste residue can also be further processed and potentially sold or used as soil amendment with fertilizing properties.
This guide has been prepared for practical use. It explains the required materials and equipment, as well as each working step, similar to a cookbook with its respective recipes. It includes all information required to develop and operate a Black Soldier Fly larvae waste processing facility. Where information is scarce or unavailable, it highlights these gaps and points to further research and development that are required.
It is worth mentioning that the approach presented in this handbook is one among many. It is based on locally available equipment and without automatization. The operations presented here have proven to work, but selected steps may individually be replaced with other procedures depending on the given context or experience.
Given the approach of this handbook, it targets readers with little or only some basic knowledge of waste management in general and black soldier fly technology in particular, who have the willingness to work with waste and to implement and operate such a facility. This guidance can also be helpful to someone who has already started with BSF treatment and is interested in obtaining other viewpoints on how things could be done.
Navigating through this guide
The manual is structured according to the five main processing units that are key to a BSF processing facility (Figure 1).
BSF rearing unit
Waste receiving and pre-processing unit
BSF waste treatment unit
Product harvesting unit
Post-treatment unit (larvae refining and residue processing)
BSF treatment facility
Waste pre-processing Treatment
Figure 1: The different units of a BSF treatment system
4 Black Soldier Fly Biowaste Processing
Although proper “waste sourcing” is of crucial importance to a well-functioning BSF facility, this unit is not discussed in detail in this manual.
The economic viability of a BSF processing facility will depend on a range of local conditions:
Scale and respective capital and operating costs of the facility
Climate (temperature, humidity)
Potential revenue from waste processing (tipping fees)
Sales revenue from larvae derived products (e.g. whole larvae, protein meal, larval oil, etc.)
Sales of the waste residue as soil amendment or its use in a biogas plant.
This manual does not fully explain the financial aspects of such a facility, but rather focuses on what we suggest are the minimum number of operating steps required for a facility. Besides the list of activities that must be conducted at specific time intervals, this manual also provides an equipment list, which is based on practical experience. However, we highlight where we feel there is potential for improving the equipment.
Throughout the text, you will come across the following icons. They indicate issues of particular importance and background information or point to research gaps.
Highlights issues of high importance
Highlights detailed information for interested readers, but is not
Highlights issues needing improvement (where further research is needed)
Highlights sampling and data collection for monitoring purposes
Waste Treatment by BSF
Understanding the natural BSF life cycle
This chapter takes a closer look at the life cycle of the Black Soldier Fly. Understanding the life cycle helps one to know why BSF is a suitable insect for organic waste management and to learn how this cycle can be “engineered” to enhance the benefits produced in terms of waste conversion efficiency and product harvest in quantity and quality.
The Black Soldier Fly, Hermetia illucens, is of the dipteran family Stratiomyidae. It can be encountered in nature worldwide in the tropical and sub-tropical areas between the latitudes of 40°S and 45°N (Figure 2).