Technological Process

After pre-processing of cloth, bag breaking and screening, Garbage is transported directly into the garage-type fermentation bin using a loading machine. The front baffle of the bin is then fixed, the sealing door is closed, the sealing air bag is filled, and then the product is recycled. The biogas liquid in the methane reactor realizes a spray reflux cycle. The retention period of the material in the fermentation bin is 2-3 weeks (actually adjusted according to changes in biogas production). The leachate is pumped into the methane-producing reactor after reflux, and the biogas produced by fermentation is purified. Then it enters the biogas cogeneration unit. In addition to part of the electricity and heat generated for self-use, the rest can be used nearby; the biogas residue produced by garage-type dry fermentation does not require solid-liquid separation. Since the biogas residue has good accumulation porosity, subsequent Commercial organic fertilizer can be produced after simple aerobic treatment.

Numerous advantages in comparison to conventional biogas processes

Controllability of biogas production

Methane content 15-20 % higher than by conventional plants

High process stability

High availability and reliable means of operation

Flexible use of feedstocks resulting from lack of sensitivity to impurities Simple and robust feedstock handling

No re-inoculation of feedstock, therefore low risk of silting

Low energy requirement for operational Compact installation footprint

Low risk of encrustation of piping, pumps and aggregates

Structure-rich solid digestate, low treatment effort for post-composting

The GICON® Process was developed by a team led by Prof. Busch from the Department of Waste Management at the Brandenburg Technical University in Cottbus together with GICON, and has been internationally patented. It is specially designed for impurity-rich waste feedstocks. A batch high solid anaerobic digestion process utilizing percolation, the unique characteristic of the GICON® Process is its two process stages highlighted by the deliberate separation of the hydrolysis and methanization decomposition processes.

Two distinct stages of hydrolysis and methane formation

In the hydrolysis stage, organic macromolecules are biologically broken down into soluble organic substances and discharged as an aqueous solution – the hydrolysate. The collection of the hydrolysate from all percolators takes place in a buffer tank from which the second stage, a fixed bed digester for methanization, is continuously fed. The fixed bed, with a high surface area-to-volume ratio, provides a colonization surface to methane bacteria which are immobilized within the methane digester. The resulting liquid, which is neutralized by the biogas process, is then fed to a second buffer tank, the process water tank, and recirculated back to percolation in the hydrolysis stage

Lack of sensitivity to impurities and encrustation

A fundamental advantage of the percolation process is its lack of sensitivity to impurities. This enables the application of organic and municipal wastes, impurity-laden solids and lawn/garden wastes as well as agricultural feedstocks such as energy crops or solid manure. Furthermore, the GICON® Process offers low wear and tear. High recirculation rates in conventional percolation processes lead to salt crystals in process water which can encrust on pipes and aggregates. In the GICON® Process, the crystals are deposited in the process water tank, where the pH is highest and the temperature is lowest. Pipes are therefore better protected against encrustations and crystal sludge can be discharged in a controlled manner from the process water tank

Low energy requirement and high availability

Biogas plants based on a percolation process have low energy requirements, because among other things, no mixing technology is required. At the same time, batch operation leads to high availability. In comparison to conventional one-step batch processes, the characteristic GICON® Process immobilization of microorganisms in the methane reactor enables the residence time of the feedstock in the percolators to be significantly reduced and enables 100% fresh feedstock to be introduced into each batch. Seeding by mixing in solid digestate is not required, which also avoids silting of the digestate. Plants using the GICON® Process are therefore particularly compact in footprint.

Process stability and high biogas quality

Objectives during the development of the GICON® Process were optimal process stability and increase of biogas quality while simultaneously providing for controllability of production. The process stability is improved by the ability to create optimal conditions in isolated environments for hydrolytic and methanogenic bacteria. By mixing the process liquids from the two buffer tanks, the pH can be adjusted separately for both stages. The liquid is heated before it is fed into the digesters in separate external heat exchangers, so that hydrolysis and methane production can be operated at different temperatures levels. The decoupling of acidification and methane formation avoids a "tipping" of the process. In the fixed-bed digester for methanization of the hydrolysis product, biogas is produced with very high methane content (above 70 %). The low calorific gases produced in the hydrolysis stage are collected separately and fed to a separate use. Through this process, costs and energy can be saved in the upgrading to biomethane.

Need-based flexibility and controllability possible for the first time

Unprecedented in biogas technology is the controllability of biogas production. The vision of a permanently-available energy and disposal center is therefore almost within our grasp. The foundations of this feature are both the buffering of energy-rich hydrolysate in an intermediate storage tank, and the constant availability of the methane-forming bacteria (immobilized on a solid carrier substrate in the methane digester).This controllability makes adaptations to load transitions possible and eliminates flare losses during maintenance works and interruptions in biogas utilization. Through parallel operation of the percolators, maintenance measures can be routinely performed without interruption of operation.