CBG Plant Manpower: Roles, Skills and Training

When planning a compressed biogas (CBG) plant, the focus is often on equipment and technology. However, whether your CBG plant operates at an 85 percent load factor or only 45 percent is determined by the people who run it. The digester is a living system that responds to every action, and upgrading-compression handles gas under high pressure. That is why operators need to be trained and to pay constant attention to detail, 24/7.

In this article, we discuss the roles in a typical CBG plant, the skills they require and how the workforce can be trained in a practical manner.

How Many People Does a CBG Plant Require?

There is no standard number for staffing a CBG plant. It depends on the plant’s capacity, the feedstock used, the level of automation and the extent to which feedstock collection is outsourced. The table below applies to plants with continuous processes and does not include feedstock collection.

The number of people needed for feedstock collection varies significantly with the type of feedstock, and a considerable number of contractors are often involved. For crop residues, numbers fluctuate sharply during the harvest season. Staff numbers also increase much more slowly than capacity, which means that the larger the plant, the lower the manpower cost per unit of CBG produced.

Core Roles

Plant Manager

The plant manager is responsible for production, safety and compliance, as well as staff and budget. The manager is typically a chemical, mechanical or environmental engineer with several years of experience in the process industry, biogas, distilleries or gas processing. They need an in-depth understanding of the process and of personnel management, as well as compliance with legal regulations and reporting to lenders and buyers.

Process / Biology In-charge

This role is responsible for maintaining a healthy digester, developing feeding schedules and mixing regimes, and monitoring VFA/alkalinity trends. They also initiate measures to prevent the digester from turning acidic. A good process/biology in-charge has a background in anaerobic digestion and the ability to interpret laboratory data and solve problems related to foaming, acidification and low gas production.

Shift Engineers / Shift In-charges

For a continuous 24×7 process there are typically three shifts plus one relief, so this role requires more than one person. Shift engineers/in-charges run all operations at the plant and make decisions during their shift. They should be proficient in operating the SCADA/HMI system, issuing permits and addressing urgent issues.

Plant Operators

Operators are the core workers responsible for most of the plant’s operations. They run feeding, pre-treatment, digesters, gas holders, upgrading, compression and cascade filling. Typically, operators are ITI or diploma holders who have received training at the plant. They are responsible for following operating instructions, starting and stopping equipment, carrying out inspections and checking for gas leaks.

Lab Chemist

The lab chemist tests feedstock for total and volatile solids, digester liquids for pH, VFA and alkalinity, and gas for CH₄, CO₂, H₂S and moisture content. GOBARdhan requirements stipulate that gas quality must be continuously monitored, so verifying the accuracy of gas analysers is also the lab chemist’s responsibility. The role needs wet chemistry, analytical skills and good documentation practices.

Maintenance Team

A typical maintenance team consists of mechanical fitters, an electrician and an instrumentation technician. They handle all preventive and corrective maintenance of agitators, pumps, shredders, compressors and upgrading equipment, and address operational breakdowns. Essential skills include rotating machinery and compressor maintenance, motor and VFD servicing, basic PLC programming, and calibration.

Feedstock and Logistics Coordinator

The feedstock and logistics coordinator secures a continuous supply of feedstock by arranging collection, managing suppliers and contractors, running the weighbridge and maintaining feedstock stocks. The role requires excellent coordination skills, knowledge of suppliers’ requirements and familiarity with local languages and customs.

FOM Production and Sales

Since fermented organic manure (FOM) is a significant source of revenue, a dedicated person should manage solid-liquid separation, dewatering, enrichment and bagging of FOM, and its sale to dealers and farmers. This role requires knowledge of fertiliser standards and bagging, and the ability to maintain dealer networks and FPO links and promote sales to farmers.

Safety Officer (full-time or shared)

A safety officer manages the safety management system, covering permits, gas detection, fire protection, PPE, drills, incident reporting and statutory audits. Useful skills for this role include process safety, firefighting, confined-space and hot-work safety, and PESO/Factories Act compliance.

Support Staff

The plant also requires support staff, including cascade truck drivers, a weighbridge clerk, a store-keeper, accountants, administrative staff, security and cleaning staff.

A Typical Shift Pattern

A continuous process typically runs three 8-hour shifts. Each shift needs at least one shift in-charge and enough operators to cover the feed and digester section as well as the upgrading-compression section.

The day shift additionally covers the lab analyst, maintenance team, feedstock and logistics coordinator, and management. When developing the shift pattern, account for holidays, leave and training, and avoid overloading any one shift.

Key Skill Sets for Working in a CBG Plant

• Biological intuition – understanding how changes in feedstock or digester conditions will affect gas production and digester stability over the long term.
• Gas safety discipline – knowledge of safety procedures for combustible, toxic and high-pressure gas.
• Data management – accurate logging and record-keeping of gas production, sampling and analysis data.
• Mechanical awareness – recognising mechanical problems caused by feedstock-related issues.
• Good communication – clear handover between shifts reduces the possibility of incidents.

Creating a Training Plan for Workers

Prior to commissioning

Hire the core staff two to three months in advance and start training them. Initial classroom training should cover the basics of anaerobic digestion, P&IDs, SOPs and gas safety. Trainees should then shadow the EPC team during mechanical completion and pre-commissioning activities.

During commissioning

Commissioning is the best opportunity to learn a CBG plant, so it is critical for staff to work alongside the commissioning team during digester start-up, feed introduction and upgrading-compression start-up.

After handover

Training should continue regularly after the plant has been handed over, including:

• Refresher training sessions every quarter
• Mock drills for gas leaks, fires and H₂S exposure at least once a quarter
• Multi-skilling so team members can cover other roles
• An annual competency assessment for all operators
• OEM training for compressors and upgrading equipment

Essential Safety Training

Gas safety, PPE, permits, confined spaces, emergency shutdown and evacuation procedures should be explained to all workers, contractors and visitors. Gas detection, ventilation, standby attendant and permit-to-work procedures must be followed when working in gas-hazardous areas, pits or other confined spaces. First aid training should also be provided to all workers.

In-sourcing or Outsourcing O&M?

Many project promoters, particularly first-time investors, opt for an O&M contract with an experienced operator who brings proven processes and well-trained personnel for the first 2–5 years, depending on the contract terms. An effective O&M contract also specifies performance guarantees, regular reporting and skill transfer to in-house personnel.

How Can Bharat Bioenergy Help?

Bharat Bioenergy offers O&M services for CBG and biogas plants. During commissioning, we also train your personnel so that they gain the skills and confidence to operate the equipment. Whether you are looking for a full O&M contract or want to train your staff, talk to our team.

Frequently Asked Questions