Sludge Treatment

Sewage sludge treatment

We at P.C.S. started to develop innovative processes to optimise sludge digestion and sludge dewatering processes many years ago. Today, we are able to combine thermal or chemo-thermal hydrolysis with procedures to recover phosphates from waste-activated sludge or digested sludge. Among others, our customers benefit from high recovery rates through phosphate recycling, e.g. in the form of magnesium ammonium phosphate.

The problem

Pursuant to the new German Sewage Sludge Regulation enacted by the German federal government it is no longer possible to use sewage sludge as fertiliser on agricultural land because apart from reusable material such as phosphorus, which is used as fertiliser, it may also contain harmful substances. The disposal of sewage sludge on landfill sites has been prohibited in Germany since 2005. However sewage sludge is produced and must be further processed. There are two major aims:

  • Harness as much energy as possible from the sludge digestion process and achieve high sludge dewatering rates;
  • Recover as much reusable material (e.g. phosphorus and nitrogen) from the sludge as possible.

Our solution

We first analyse the substrate at our professional “sludge kitchen” at our Hamburg laboratory.

Based on the results we determine the combination of the procedures and processes to be used, with which you will a) best be able to harness the energy generated in the digestion process and b) achieve high phosphorus recovery rates - now and not years later from sewage sludge ash using additional procedures.

We will discuss with you your specific requirements and advise you, never losing sight of aspects such as economic viability, feasibility and contribution to environmental protection.

Your benefits

Sludge problems are a thing of the past. Here’s is why:

  • The quality of the digestion process increases → higher gas yield, more usable energy
  • You meet the 50% phosphorus recovery rate requirement, including a high share of dry solids, which allows you to dispose of the sludge in co-incineration plants and achieve the required recovery rate of phosphorus in the form of plant-available MAP.
  • You save storage, transport and mono-incineration plant costs
  • You use individual, not manufacturer-bound procedures and methods

Our references

Berliner Wasserbetriebe

engineering consulting
Task:

Berliner Wasserbetriebe asked us to redesign the original reactor in Berlin with the aim to fully automate the discharge of MAP generated from the process.

Project Details

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Make an appointment to meet us in person. We will look at your problems from all angles and provide specific advice independent of manufacturers, backed up by the latest expert knowledge.

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Multi-talented thermal hydrolysis

The thermal hydrolysis process can be installed upstream or downstream of the digestion process as stand-alone technology or in combination with other procedures. It can also be a stand-alone tool to work on processes, like a toothed wheel within the overall sludge treatment process.

If the thermal hydrolysis as stand-alone technology is installed upstream, sewage plant operators will achieve a higher rate of digestion, higher gas yields and reduced sludge volumes.

Hydrolysis systems are usually installed downstream of the digestion process if you want to optimise the dewatering rates of digested sludge.

If biological P-elimination is the standard procedure used at your wastewater treatment plant and you decide to treat waste-activated sludge hydrothermally, downstream process steps will offer new options such as, for example, the cost-efficient recovery of nutrients.

Depending on what you want to achieve, thermal hydrolysis can be integrated into your wastewater treatment plant’s existing system at different process stages and connected to and/or combined with other treatment processes. The following locations have proven to be the most beneficial:

  • Thermal hydrolysis of thickened waste-activated sludge: upstream of digestion
  • Thermal hydrolysis of digested sludge: upstream of dewatering

If you combine the thermal hydrolysis system with phosphorus recovery through precipitation of MAP, you can install it either upstream or downstream of digestion. To reduce nitrogen rates, you can use separate sludge water treatment methods such as stripping.

Get in touch with us! We will be happy to advise you on the combination and arrangement of equipment that will optimise your specific digestion process.