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Sewage sludge reuse Phosphate recovery with an innovative HTC technology (HTCycle)

Periodic Reporting for period 1 - HTCycle (Sewage sludge reuse Phosphate recovery with an innovative HTC technology (HTCycle))

Reporting period: 2015-07-01 to 2015-12-31

The main purpose of this feasibility study report performed by AVA-CO2 was to do a research about the sewage sludge production and disposal methods conducted in European countries in order to find potential markets for the promotion of the Hydrothermal carbonization technology (HTC) as a high potential sewage sludge treatment method for the upcoming years. While wastewater treatment has by now become the norm in Western and Central Europe, treatment and disposal of the sewage sludge generated by wastewater treatment plants (WWTPs) continues to be a challenge. In recent years, several sewage sludge treatment methods have emerged on the market, aiming to (1) reduce the adverse environmental effects associated with irresponsible sewage sludge disposal and (2) reduce the costs of sludge disposal. The most commonly used treatment methods are direct spreading on agricultural soil, composting and incineration (co- or mono-incineration). Given the high levels of heavy metals and organic pollutants in sewage sludge, its direct use as fertilizer is recently becoming the topic of intensive debate, with several EU countries (e.g. Germany) moving towards an almost complete ban of agricultural sludge utilization. While incineration has gained popularity in recent years, the need to dry the sludge beforehand with considerable amounts of energy, large hauling distances as well as high transport costs from WWTPs to incineration facilities have made this disposal method inefficient and costly. Additionally, if phosphorus is not recycled from the sewage sludge ash, this nutrient is lost indefinitely from the economic cycle. Hydrothermal carbonization (HTC) – the technology proposed by AVA CO2 – provides an innovative, energy-efficient and economic solution targeting the above-mentioned pitfalls of other disposal methods. With the diverse application possibilities of the produced hydrochar (e.g. as solid fuel, activated carbon, soil remediation material) the HTCyle technology promises to turn sewage sludge disposal from a costly process into a lucrative business opportunity.


In order to fulfil the objectives extensive research was done and the following tasks were carry out.

- Identification and characterisation of the supply side and main target countries for the AVA-CO2 HTC process
- Identification and specification of potential customer profiles
- Creation of potential client groups with different sludge suppliers/producers
- Developing of a market-study with summarising the currently supply and demand
- Establishing local distributions and set up partnerships in the detected main target countries
- Internal planning for the producing capacity (knowledge, employments, etc.)
- definition and implementation of the legal acceptance and safety regulations
- Definition of the requirements for the AVA-CO2 HTC plant for the commercialisation (CE- and
DIN EN-certification, machinery directive, etc.)
- Developing of a business plan to determine the costs and revenue of the AVA-CO2 HTC system
In order to tap into this potential, a thorough market analysis and feasibility study had to be carried out. This report summarises the results of AVA’s research regarding sewage sludge production levels and common disposal methods in the main EU28 producers of sludge (Germany, Switzerland, Denmark, Sweden, the Netherlands, France and the UK). Based on these results, the report identifies promising potential markets for the promotion of HTC as a sewage sludge treatment method and discusses possible market entry obstacles (legal or economic) and the likelihood of success in the penetration of these markets. After a short background into the characteristics of sewage sludge and general information on sewage sludge disposal in the EU (chapter 2), detailed information about target regions and clients are presented in chapter 3, 4 and 5. Finally, an internal analysis of AVA CO2 is conducted in chapter 6, presenting highlights of the company’s business plan.
Production levels of sewage sludge differ considerably between different European countries, depending on the population, the percentage of households connected to the sewer system and the treatment methods used at WWTPs. Per capita production also differs, with the mean value in the EU at ~55 g/(P.E. × d) . The total sludge production from urban WWTPs in selected European countries has been identified and described.

The main sewage sludge producing countries – and hence large potential markets for application of HTC – include Germany, Switzerland, the UK and Scandinavian countries. Depending on the legal framework for sludge disposal in these countries and the market shares of competing technologies, the potential for widespread market uptake of HTC has been determined. Not only do the generated amounts of sludge produced differ largely among Member States, but the disposal methods applied show a large variety across countries. The treatment and disposal methods chosen in each country may depend on economic, political or legal, environmental and/ or logistic (e.g. agricultural land availabilities nearby) factors, but often also on the lack of suitable technologies and an underdeveloped market for more efficient and sustainable disposal methods.

By 2020, sewage sludge reuse in agriculture and sewage sludge incineration are expected to be the dominant practices in EU-27 . The report provides a short overview of advantages and disadvantages of both disposal methods: agricultural utilization vs. incineration (co- and mono-inicneration).
Identified markets and suitable biomass waste streams for the treatment in the AVA-CO2 HTC Systems in potential markets in Europe. Furthermore the requirements of the AVA-CO2 HTC treatment plant for commercialisation were defined.
Based on the identified market, biomass streams, countries, requirements (legal acceptance and safety) etc. the AVA-CO2 HTC Treatment should be established in the targeted markets and provide high-grade fuels from wet biomass streams in an eco-innovative as well as resource-efficient treatment process. As the feasibility study showed the sewage sludge is a very promising potential waste stream which contain an important organic fraction and is available in all EU countries. The evaluation per Country was depending on the volume of sewage sludge produced and the disposal process available as well as the suitability for the AVA-CO2 HTC technology. As final conclusion we can state that we selected the following five European countries as most suitable for the AVA-CO2 HTC technology: Germany, Switzerland, UK, The Netherlands and Denmark. The same procedure was done for the selection of the most suitable sludge streams for the application of the
AVA-CO2 HTC technology, which was mostly depending on the generation of the various sludge streams for the years 2004, 2006, 2008 and 2010.
AVA-CO2 Pilot plant in Karlsruhe, Germany