Seropedica Landfill

Rio de Janeiro – Brazil |

INTRODUCTION
The managers of the landfill which, at the time already contained almost 12 million tonnes of waste deposited in just 4 years, asked for consultancy on the operational status of the collection network and the intake and combustion system of the existing biogas and to propose a system upgrade project at the same time as the extension of the landfill and resulting increase of the amount of gas to treat. 

The intake system consisted of a pre-assembled plant on a metal frame, combustion was ensured by two units, one sized for a flow of 2,500 Nm3/hr (of LFG50, i.e. biogas containing 50% methane), the second for 5,000 Nm3/hr.

FIELDWORK
The project development could not exclude an initial careful analysis of the waste deposit management methods, organisation of the staff involved in biogas management and, lastly, the elements making up the collection network – vertical wells, horizontal trenches, and the condensate and leachate transport, discharge and collection lines. We carried out a field survey and noted the operational conditions of all the existing system.

ANALYSIS OF THE INFORMATION
After the fieldwork, the information acquired was analysed and a report was prepared presenting the topics and highlighting the critical points found. The findings acquired through the investigations were taken into consideration in the definition of the construction details subsequently included in the project documents of the landfill extension, which considers the banking up of a total of just over 101 million tonnes of waste until 2039.

DOCUMENTS OF THE PROJECT PRESENTED

  • Biogas production prospect
  • Sizing report on the collection network components and the equipment for the intake and combustion plant
  • Technical memorandum with the technical specifications for each element making up the collection network and the biogas plant
  • Tables, diagrams and graphic content
  • Project dynamics

CREATION OF THE FACILITY
October 2015 – As a result of the project presented, the landfill operator assigned the extension of the intake and combustion plant collection network to us. The collection network was redefined through the supply and installation of HDPE piping and products. In detail, some existing adjustment stations were modified, reinstating the full functionality, and 7 new adjustment stations were supplied. The intake and combustion plant was reconfigured for the connection of the three new biogas conveying manifolds from the landfill, two extractors-compressors of 7,500 Nm3/hr and a new flare of 5,000 Nm3/hr, in addition to electrical and analysis boards and supervision system. The two existing flares of the previous plant were integrated, reaching the total combustion capacity of 12,500 Nm3/hr.

March 2016 – Following the checks set out in our Inspection and Test Protocol, we commissioned the biogas plant and setting of all the operational parameters set out in the supervision software. At this time, our operators trained the local operators on the daily maintenance and control of the plant. The operation of the system is supervised by our control unit in Italy via an internet connection.

EXTENSION OF THE FACILITY
April 2017 – In line with the landfill extension stages and the related increase in the amount of extractable biogas, the first extension of the biogas plant was made in conformity with the project for the whole system. A new extractor-compressor da 7,500 Nm3/hr and a new flare of 5,000 Nm3/hr were installed in addition to the supervision system. This extension led to a total intake-compression capacity of 22,500 Nm3/hr and a total combustion capacity of 17,500 Nm3/hr.

July 2021 – In line with the landfill extension stages and the related increase in the amount of extractable biogas, the second extension of the biogas plant was made in conformity with the project for the whole system. A new extractor-compressor of 7,500 Nm3/hr and a new flare of 5,000 Nm3/hr were installed in addition to the adaptation of the supervision system. This extension led to a total intake-compression capacity of 30,000 Nm3/hr and a total combustion capacity of 22,500 Nm3/hr.

October 2021 (forecast) – Following a decision of the plant operator to power it using renewable sources, 2 biogas-fuelled electricity generators. Biotecnogas was commissioned with the supply and installation of the dehumidification section of the biogas diverted to these generators. The new section will be integrated into the existing plant and the supervision system will also be updated as a result. It will have a capacity of 1500 Nm3/hr. It will also be prepared for a possible future expansion of another 1500 Nm3/hr.