The current sludge problem

• The treatments which allows the sludge recovery require the implementation of such processes as the anaerobic digestion. This treatment offers a strong economic advantage due to the produced biogas and a transformation in biomethane which allow the reinjection in the natural gas network.
• Sludge produced respond more and more to strong constraints and requirements, as dryness, the stabilization, the harmlessness and the traceability. The final routes of disposal and reuses are becoming reduced, whereas the quantities of produced sludge increase ceaselessly.
• Selecting the best processes that allow to reach the final route is a strong part of a sustainable development policy and a medium–term cost control for communities.
• In the face of the problem, ENVIRO-CONSULT acquired a know-how recognized for the technical and economic approach of drying processes routes and developed tools of analysis allowing to make the comparison between:
• • Sludge pre-drying at 60-65 % dryness and total dryness at 90 %.
  • Best available technology (BAT) allowing to approach co-incineration between sludge and household solid waste
  • The alternatives for the reuses of dried sludge : agronomic, energy recovery, and materials
• The research of sludge final routes, the most suited to the request of customers, accompanied with a continuous reduction of the global costs and remains sustainable goals and the main objective of ENVIRO-CONSULT.

Expertise Audit Diagnostic

• To allow the safety operation of drying processes, it is advisable to reduce the potential risks by conducting a risk analysis of the dangerous substances atmosphere and explosive atmospheres (DSEAR) of the various zones of the drying installation.
• Numerous drying process of drying depend also on severe operation conditions (wear, corrosion, scaling, clogging…). Functional failures appear.
• An analysis based on the reliability turns out to be necessary. ENVIRO-CONSULT possesses the experimental knowledges to identify the failures and the associated causes of various equipment used for the drying process.
• For any drying process, ENVIRO-CONSULT studies the operational security and safety of the operators and goods.
• ENVIRO-CONSULT brings its expertise to:
• • build the failures trees
  • propose the best solutions to the problems
  • accompany the customer in the presentation of the selected solution
  • follow up of maintenance and ameliorative works
  • present the execution of works with template documents and pictures
  • help in the technology watch and follow the trend of drying technologies.

Project ownership assistance

• Construction of sludge processing plants by anaerobic digestion and drying refer to intellectual services dealing with predefined scenario of technical, architectural, financial solutions in a program of operation realized by a project ownership assistance.
• In developing of the file ” Marché ”, ENVIRO-CONSULT advise its clients to raise the technical complements which are often necessary to fill into the tender form.
• ENVIRO-CONSULT brings to communities, the necessary assistance on technical items for the elaboration of the functional program dealing with the requirements on:
• • the conditions of digestion: anaerobic mono-digestion or co-digestion under mesophilic or thermophilic process
  • the behavior of pre-dried material or dried with the aim of their reuses
  • the guarantees of performances to achieve
    • the global evaporation capacity
    • the dryer specific evaporation rate
    • the recirculation ratio
    • thermal and power energy criteria
    • resistance against wear and corrosion
  • costs of operation :energy, labour, maintenance and control
  • the more specific particular aspects of sludge drying process
    • operation security
    • reliability and safety for DSEAR
    • Operating conditions.

Technical assistance

• At the installation’s construction works achievement, ENVIRO-CONSULT intervenes in various fields:
• • By supporting the commissioning engineers and as a technical support on the sludge characteristics like biochemical and rheologic analysis towards anaerobic digestion and drying.
  • In the training sequence of operators and in particular situation scenario for smoothly increase the organic load to digestion.
  • To bring support for the preparation of analysis protocols and operation follow-up files.
  • During the process optimization: throughput, organic load, blending, cocktail, performances,…
  • For the maintenance plan and the spare part management.
  • By assistance during cleaning of digesters in order to achieve safety conditions and during inspection of drying plants for wears.
  • During upgrading works of digestion and drying plants
• Moreover, we provide assistance in:
• • Reporting files for maintenance works
  • Maintenance commercial and technical follow-up
  • Implementation and upgrading of maintenance contracts.
• By its actions in these fields, ENVIRO-CONSULT noticed that the return of experiments given to operators and the application of a maintenance preventive program within a framework contract, allowed to improve the biogas production and to increase considerably the annual availability of dryers operation.

Miscellaneous works

• Communication, training and conferences
• ENVIRO-CONSULT participates in numerous conferences on anaerobic digestion and the sewage sludge management with thermal drying processes.
• Sharing experiences and developments, as well as the results of experiments of European operators at conferences, are useful for self-reflection and analysis on the future of sludge routes policy and give a support for participants’ projects.
• ENVIRO-CONSULT is dealing in the different phases of sludge treatment, the biogas recovery, the biomethane conversion and the reuses of fuel materials as dried sludge for cement plants including each sequence of sludge treatment before and after sludge drying:
• • Wastewater treatment plant management with anaerobic digestion and drying
  • Anaerobic mono digestion and co-digestion treatments
  • Conditioning and dewatering
  • Liming and pelletizing
  • Co-incineration of pre-dried sludge and municipal solid waste
  • Dedicated incineration
  • Reuses of dried material
  • Mechanical elaboration of new dried material as pellets, bricks,…
  • for comparative studies, processes expertise, proposals of drying plants improvement and upgrading

Excerpt from references

ENVIRO-CONSULT has an extensive experience with numerous missions and services in various communities, engineering companies and schools such as:

• Communities:

  Wastewater unions for large French and foreign cities

  • EVREUX PORTE NORMANDE
  • RWA AMSTERDAM (NL)
  • SIAAP PARIS
  • SIBA ARCACHON
  • SIDEPAQ QUIMPER
  • SIVOM METZ
  • SIVOM SETE
  • SIVOMAO ORLEANS
  • SIVU PAU
  • SOUTHWEST WATER (UK)
  • VILLE de LIMOGES
  • VILLE de ZÜRICH (CH)
  • VILLE de SHANGHAI (CN)
• Sludge treatment engineering companies:
  • ABT (S)
  • ALFA LAVAL SEPARATION AB
  • EDF
  • INOVA
  • NOVO NORDISK (DK)
  • ROHM et HAAS
  • SMS Buss (D)
  • SOGEA
  • SUEZ
  • SWECO (S)
• Institutional actors:
  • AFNOR
  • AGENCES DE L'EAU
  • ANVAR
  • CAISSE DES DEPÔTS
  • CCI de COLMAR
  • CCl de MULHOUSE
  • CCI de PARIS
• Training schools:
  • CFDE
  • CNFPT
  • EFE
  • EUROFORUM
  • IPI
  • IVF
  • NANCIE
  • OIE