Case Study

Company

UK Based Private Agricultural Business

Location

Anaerobic Digestion System

Industry

Agriculture

Cost

Confidential

Introduction

This confidential client is an independent business specialising in pig, beef and arable production. Historically the company used surplus or rejected human food to supplement the pigs diet, thereby avoiding it going to landfill. The company was seeking ways to utilise a broader range of food waste in a way that would enhance operational efficiency, profitability and provide environmental benefits.

The Project Scope

At the outset, Anaerobic Digestion was identified as a viable option for processing both the organic waste imported to site and that generated as a by-product of pig production. Waste products such as beer, fat and packaged foods that would be unsuitable as animal feed are mixed with pig manure to create organic fertiliser. Additionally the Anaerobic Digestion process is used to provide energy in the form of electricity that is used by the company on site with surplus energy being fed to the national grid.

In spite of the known benefits of Anaerobic Digestion across the waste management industry, our client’s early search for a suitable digester system supplier had been unsuccessful. The principal reason for this was that the digester system suppliers were unable to provide the level of design and process engineering support needed to ensure the digester’s effective integration with the clients existing complex farming systems whilst still allowing for the full utilisation of the diverse range of feedstock available.

The Challenge

The project was in real danger of stalling at the point when PROjEN was approached by our client to collaborate in the design and delivery of an Anaerobic Digestion system that met the specified requirement. Our client found that PROjEN is one of very few UK companies who were not aligned to any single technology provider and yet still retained the necessary expertise to deliver against the extremely complex and challenging brief.

There were a number of challenges that PROjEN had to overcome. Time was short, the plant had to be designed, procured, constructed and commissioned to deliver 1MWe in 14 months. In addition, to minimise cost the project had to utilise existing on-site systems and as much of the existing physical infrastructure as possible. This included utilising existing energy systems to take hot water or biogas from the Anaerobic Digestion process.

The plant had to be able to process in-house animal slurry as well as a wide range of solid and liquid food and food process waste from outside. Additional requirements included the ability to export excess electricity to the national grid as well as the capability for the design to be upgraded to 2MW output and above through the inclusion of additional digestion capacity in the future.

Outcome

The plant was delivered on time and on budget. Every specification was met and in some areas exceeded. For example 1MW was achieved on a reduced feedstock tonnage with a very high rate of conversion of feedstock to biogas. By optimising the feed blending system to produce a 17-20% dry matter digester feed (soup), parasitic load on the plant and the amount of digestate was reduced whilst increasing the nutrient concentration in the organic fertiliser produced.

PROjEN’s recommendation that a two phase biological system seeded with two sets of complementary bacteria proved to be very stable and controllable allowing very high ammonia content feedstock.

The operational systems that PROjEN developed and implemented provided management clarity and simple clear instructions for the digester operators with clear division of responsibility. PROjEN ensured a high degree of system assurance with MCC controls, PLCs and SCADA software. 24 hour engine remote monitoring, automatic dial out alarms to the operator at night and weekends as well as a fully automated manure and digestion handling system.

All PAS110 and ABPR requirements were met as well as the environmental and cost reduction targets with a reduction in carbon footprint, energy costs and pig unit operating costs. In addition very high nitrogen organic fertiliser with very low odour was produced for use on local farms and 18,000 tonnes per annum of food waste destined for landfill was now being used productively.

In spite of the engineering complexity, environmental and aesthetic sensitivity of this project, planning consent and permitting was awarded without dispute or negative response from the neighbourhood thanks in large part to the engagement strategy that PROjEN adopted.

Project Cost

Confidential

Timescale

Time was short, the plant had to be designed, procured, constructed and commissioned to deliver 1MWe in just 14 months.

Client

UK Based Private Agricultural Business

Benefits

  • Greater certainty of outcome – PROjEN provided the necessary expertise to ensure the project met all the specifications and provided the oversight to ensure the project was delivered on time, on budget and in full.
  • Improved performance – 1MW was achieved on a reduced feedstock tonnage with a very high rate of conversion of feedstock to biogas.
  • High degree of system assurance – PROjEN ensured a high degree of system assurance with MCC controls, PLCs and SCADA software. 24 hour engine remote monitoring, automatic dial out alarms to the operator at night and weekends as well as a fully automated manure and digestion handling system.
  • Collaboration with the local community – Planning consent and permitting was awarded without dispute or negative response from the neighbourhood thanks in large part to the engagement strategy that PROjEN adopted.

Conclusion

By applying their technical, design, project management and stakeholder engagement skills, PROjEN were able to take a complex and technically challenging project that had effectively stalled and deliver a successful outcome on every measure in just 14 months.