Multi-stage composting system using black soldier fly larvae

Abstract

A multi-stage composting system for black soldier fly larvae, consisting of a stacked housing with an upper feeding chamber with integrated self-harvesting ramps for the larvae leading to an external collection container, a middle maturation chamber below the feeding chamber for continued decomposition and completion of the larval stage, and a lower end chamber for the accumulation of larvae-free compost, with perforated partitions between the chambers and a passive ventilation channel ensuring aerobic conditions and staged material transport.

Description

Application area of ​​the invention

[0001] The invention relates to systems for processing biowaste for decentralized composting, in particular multi-chamber systems with black soldier fly (BSF) larvae with passive ventilation, staged decomposition and self-discharging ramps for larva separation. Background of the invention

[0002] Black soldier fly larvae rapidly convert organic waste into biomass and residues. However, in households or small farms, the adult larvae often have to be manually sorted, and controlled ventilation is lacking, leading to odors and inefficiencies. Passive, IoT-free systems with staggered material flow can reduce labor by allowing the larvae to self-harvest via ramps. Multi-layered chambers ensure continuous decomposition and pupation without disrupting the feed in upstream areas. Passive ventilation and leachate management reduce anaerobic zones and odors. A well-configured vertical system adheres to best practices in energy-efficient waste processing and leverages greenhouse-like ventilation strategies.There is still a need for a compact system with continuous feed, integrated non-mechanical larvae separation, odor-minimizing ventilation and staggered compost maturation. Summary of the invention

[0003] The invention relates to a three-stage composting system consisting of: an upper feeding chamber with BSF larvae and integrated escape ramps to a harvesting container; a middle maturation chamber that collects overflow and semi-decomposed substrate, allowing the remaining larvae to continue feeding; and a lower end chamber for larvae-free compost maturation. A passive aeration path with sieve openings and a vertical chimney effect ensures aerobic conditions while minimizing odor. The chambers are arranged one above the other in a closed, but breathable housing with leachate drainage and removable access flaps to allow continuous feeding and regular harvesting without mechanical separators.

[0004] In some embodiments, the upper chamber has inwardly sloping floors that guide the pre-pupal larvae (crawling behavior) to the ramp inlets. The middle chamber uses mesh floors or perforations for the gradual transport of material and larval passage. The lower chamber is equipped with a fine sieve to retain larvae and collect finished compost. An external, removable larval collection cup serves as the inlet for the ramp outlets. Odor control is improved by a biofilter cap on the ventilation pipe. Detailed description

[0005] The housing consists of three vertically stacked chambers separated by perforated partitions. The top chamber has a hinged feeding lid with a seal, splash guard, and fine-mesh insect screens on opposite sides for cross-ventilation. Ramps begin near the chamber floor and spiral upwards to the exit openings. The ramp surfaces are textured with micro-grooves to facilitate crawling, and inclines of approximately 35–40 degrees take advantage of the climbing behavior of pre-pupal larvae. The exit openings lead to a removable, lidded harvesting container.

[0006] The floor of the upper chamber slopes gently towards the ramp inlets and features a sieve or slot pattern that allows small particles and liquids to settle without clogging the ramps. A coarse sieve (e.g., 3–5 mm) is positioned above a finer sieve (e.g., 1–2 mm) to prevent compaction and maintain air circulation. The partition allows semi-decomposed substrate and larval remains to pass into the middle chamber during regular mixing or as the mass decreases.

[0007] The middle chamber provides a deeper substrate for further decomposition and complete nutrient uptake by the remaining larvae. Adjustable baffles regulate the vertical movement of the material. Passive aeration is achieved through side openings with replaceable activated carbon or coconut fiber inserts, which act as biofilters. An additional ramp can be integrated to guide more advanced-stage larvae into a second, smaller collection container.

[0008] The lower post-treatment chamber is protected from larvae by a fine-mesh floor and an upward-facing edge that makes climbing difficult. This chamber promotes the aerobic maturation of the crop residues into a stable, larvae-free compost. A front access door with a latch and seal allows for regular removal; a removable sieve inside serves to separate fine particles.

[0009] A vertical ventilation tower at the rear connects all chambers via channels with baffles, creating a chimney effect through temperature differences. Each chamber has adjustable vents for flow regulation; all external openings are sealed with fine stainless steel mesh to keep out insects. At the top of the tower is a small passive biofilter cartridge filled with moistened coconut fiber substrate or biochar to reduce odors. Condensation drains away via drip edges to prevent external contamination.

[0010] The leachate is channeled through sloping bases and a central drain into a sealed leachate container with a check valve to prevent odor backflow. The interior surfaces are made of smooth, non-absorbent materials for easy cleaning; corners are rounded to prevent the accumulation of residue.

[0011] The frame allows for modular disassembly: each chamber can be slid out on guides for cleaning. The seals are food-safe; the fasteners are corrosion-resistant. Optional thermal insulation panels ensure a stable internal temperature. The footprint is suitable for balconies or agricultural barns; casters with brakes ensure mobility.

[0012] The system operates using a continuous feed process: users add waste to the upper chamber; larvae feed, develop, and collect themselves via ramps in the collection container; partially processed material falls into the middle chamber for further decomposition; finished compost collects in the lower chamber and is regularly removed. Passive aeration and biofiltration ensure aerobic conditions with low odor, thus reducing energy and labor costs compared to mechanical separation.

Claims

[1] A multi-stage composting system for black soldier fly larvae, consisting of a stacked housing with an upper feeding chamber with integrated self-harvesting ramps for the larvae leading to an external collection container, a middle maturation chamber below the feeding chamber for continued decomposition and completion of the larval stage, and a lower end chamber for the accumulation of larvae-free compost, with perforated partitions between the chambers and a passive ventilation channel ensuring aerobic conditions and staged material transport. [2] Device according to claim 1, wherein the feeding chamber has inwardly inclined floors that guide fully grown larvae to ramp inlets, ramp surfaces with grip grooves in climbing angles adapted to the behavior in the prepupal stage, and an insect net ventilation with a biofilter element to minimize odors. [3] Device according to claim 1, wherein the post-processing chamber is protected from the penetration of larvae by a fine mesh grid and a lip geometry and has an access door and a removable sieve insert for the removal of stabilized, larvae-free compost. [4] Device according to claim 1, further comprising a passive ventilation tower fluidically connected to each chamber and having adjustable vents and condensate return, and a seepage water management system with inclined bottoms and a sealed collection tank with a non-return valve.