From 16 to 20 June 2019, the International Water Association IWA hosted its “12th International Conference on Water Reclamation and Reuse” in Berlin: over 400 experts from more than 40 countries, more than 200 lectures, more than 120 posters, exhibitions, workshops and technical tours on the complex of “Overcoming Water Stress through Water Collection and Reuse”. In times of advancing climate change, water management is becoming increasingly important, as we experience in our daily work.
Part of the program was a tour of the former sewage farms in Berlin Hobrechtsfelde called “Hobrechtsfelder Rieselfelder”. AKUT has organized that tour.
In the information centre “Gut Hobrechtsfelde”, the former warehouse, there is a beautifully prepared exhibition on the history of Berlin’s wastewater treatment, in particular the sewage farms. The model of the agricultural use of the sewage farms around 1920 shown there is designed precisely. The Hobrechtsfelder Rieselfelder were taken out of operation after the commissioning of the sewage treatment plant north (today: WWTP Schönerlinde) in 1985. Both the drainage pipes, which continued to drain the area, and the heavy metals and phosphates, which had accumulated in the soil over the decades, remained in the soil. The reirrigation of the sewage farms was planned and implemented in 2004 by the AKUT / P2M / Spiekermann GmbH working group. A part of the existing drainage ditches including the drainage pipes were sealed, whereby a long retention time was aimed at. Re-irrigation of areas that had fallen dry became possible. This is done with already purified wastewater from WWTP Schönerlinde, which is further purified and hygienised at the request of the Lower Water Authority within the Hobrechtsfelder Rieselfelder. The treatment is carried out without electrical energy demand and with the lowest operating costs, as no operating resources are used. A system consisting of different zones, such as deep water zone, shallow water zone, overgrown zones and ground passages, has been created for the more extensive near-natural wastewater treatment within this so-called cleaning biotope. Since only limited data were available for the effect of the individual components, AKUT had planned pilot filtration plants / test basins for practical evaluation of the possible variants. Within the framework of a research project, not only nutrient degradation rates and hygienization were investigated, but also the removal of pharmaceutical residues and of other micropollutants. After completion of the test operation, the pilot plant has been adjusted for continuous operation. A good ten years after the re-irrigation had started, not only a large number of birds but also beavers have settled in the area. As planned, the sewage farms and the surrounding biotope are used as a silvopasture system where livestock and horses are moving independently with the side effect of low cost landscape conservation.
The conference participants from all over the world were impressed by the near-natural technology of the 19th century with sewage farms for the treatment and agricultural use of wastewater and nutrients. But even in the 21st century, when regional water scarcity is expected, there is great interest in near-natural solutions to strengthen the water balance through water recycling. At the same time, carbon sequestration in wetlands around the world represents an important contribution to climate protection.

We would like to take this opportunity to thank

The conference “BLUE PLANET Berlin Water Dialogues meets AquaNES” will take place in Berlin on 09 April 2019 from 9 am to 5 pm. The conference meets every year to promote cooperation and knowledge exchange across industries. This spring, the research work and innovations of the Horizon 2020 project AquaNES will be specifically presented and debated through lectures, panel discussions and World Cafés.
AquaNES is a research network that investigates and promotes wastewater and drinking water treatment through a combination of near-natural and technical systems through 13 different demonstration projects in Europe, India and Israel. A wide range of climatic and hydrogeological factors will be covered and processes such as bank filtration, Managed Aquifer Recharge, Constructed Wetlands and technical pre- and post-treatment options will be tested and improved.
AKUT has been involved in the research project AquaNES since June 2016. Together with partner companies such as Berliner Wasserbetriebe (BWB), Kompetenzzentrum Wasser Berlin (KWB) and Erftverband, AKUT will present the results and hurdles of the combination of near-natural and technical systems for wastewater treatment and water treatment.
In cooperation with the BWB and the KWB, AKUT has developed a pilot plant at the Schönerlinde site to remove trace substances and pathogens from the effluent of the wastewater treatment plant. For this purpose, two different planted soil filters with upstream ozonation were built and their effect on improving water quality was investigated. Regina Gnirss (BWB) will present the results of the two-year pilot in her lecture “Ozonation combined with natural filtration processes – water quality gains”. In addition, Andrea Brunsch (Erftverband) will present the results of the pilot plant at the Rheinbach site in her lecture “Flexible use of modified retention soil filters to treat wastewater treatment plant effluent and combined sewer overflow”, in which a retention soil filter is used flexibly for the treatment of wastewater from wastewater treatment plants and mixed water overflows.
After the presentations AKUT and AUTARCON will lead the discussion group “Solutions for rural communities, remote locations and emerging countries” and will be available for questions and discussions on the topic.
The exact programme and further information on “BLUE PLANET Berlin Water Dialogues meets AquaNES” can be found at http://blueplanetberlin.de/next-event/ .

As part of the GIZ project “NEXUS – Water, Energy, Food Security”, a total of 36 participants were trained in a workshop on solar irrigation lasting several days in September 2018. The workshop took place in the Universidad Católica Boliviana (La Paz) and was attended by local and international experts, researchers and students as well as members of Bolivian institutions and authorities (e.g. Ministry of Environment and Water). The participants shall serve as multipliers by integrating the gained knowledge into their daily work.

The contents of the workshop included the topics renewable energies, description of typical photovoltaic applications with focus on agriculture, description and characterization of solar water pumps, irrigation needs and techniques, water needs, planning and design of solar irrigation systems, economic evaluation and financing of solar irrigation systems, description and practical application of the tool box “Solar powered irrigation systems” as well as practical applications and design of solar pump and irrigation systems.

The workshop can be classified as a success. More than half of the participants stated in an evaluation that they could apply the acquired knowledge in their field of work and all participants stated to be satisfied or very satisfied with the results of the workshop. As a result of the discussion between members of various stake holders the potential for solar irrigation in Bolivia could be classified as very high.

The workshop is one of several training cycles within the GIZ project “NEXUS – Water, Energy, Food Security”. This project, which runs from August 2017 to October 2019, includes workshops of this kind as well as the development of management models and financing concepts for two selected pilot projects with Nexus character and Integrated Water Resources Management (IWRM).

AKUT has been commissioned to provide advice for a multi-purpose dam project (Misicuni). A water distribution plan is to be elaborated in order to balance out the water use between agricultural use (irrigation), drinking water supply and secure energy production.

The adaptation to climate change (e.g. reduction of the available quantity of water, increased need for irrigation) shall be achieved through the development of proposals for the management of the limited resource of water with the various user groups.

A GIS-based open-source information system is to be set up in order to present and design the water supply and distribution in a transparent manner.

Another important objective of the project is poverty reduction. Solar irrigation should contribute to this by reducing water and energy consumption. In addition, poverty is to be reduced by reforestation and the introduction of agroforestry systems to sustainably improve land use in the upper reaches of catchment areas.

 

Picture: Group photo at the end of the workshop

Companies that discharge production waste water into the sewage system (indirect dischargers) must comply with the discharge limit values of the respective wastewater utilities. If limit values are tightened the challenge is to develop particularly economical solutions that avoid the installation of a complete new wastewater treatment plant. AKUT was assigned to develop a solution for a similar situation regarding the wastewater discharge of the phosphating plant at Robert Bosch Automotive Steering GmbH in Berlin-Wittenau.

Current studies show that the implementation of technical adaptation and optimization measures at the chemical-physical waste water treatment plant has been successful in regards to tightened limit values. The measured total phosphate values in the discharge of the cleaning plant after the conversion have dropped to 90 percent less than the new limit values for discharge into the sewer system of Berliner-Wasserbetriebe (BWB).

The effluent limits for total phosphate were reduced to 50 mg/l by BWB beforehand.

Robert Bosch Automotive Steering GmbH had then decided to technically convert the existing plant for the removal of metal ions from wastewater to ensure compliance with the reduced phosphate discharge limit value.

AKUT Partner designed the cost-effective adaptation solution after an intensive assessment.

By converting, technically supplementing and optimizing the existing treatment plant, the phosphate is (now in addition to the previously precipitated metal ions) precipitated with automatically dosed lime and separated from the wastewater in an existing chamber filter press.

The contract included that the selected plant concept has been supervised and monitored until final acceptance and commissioning.

As requested by the customer the TÜV approval of the now semi-automatically operated chemical-physical wastewater treatment plant passed the plant without imposing any additional requirements.

Other relevant effects of the extensive automation of the wastewater treatment process are time savings for the operating personal and a reduction of the electric energy demand.

The low investment costs (compared to the installation of a new wastewater treatment plant) and the positive effects on operating costs increase the overall profitability of the phosphating plant in Berlin-Wittenau.

 

Photo: Robert Bosch Automotive Steering GmbH, Berlin – Wittenau. Buffer tank for the phosphate-containing wastewater, in the background the chamber filter press for separating the lime sludge.

Overall, the framework conditions in South Africa for the generation of electricity from sewage gas are rather difficult. The remuneration for feed-in from renewable energies is fixed at auctions, this procedure prefers scalable technologies such as photovoltaics. Biogas, on the other hand, is limited by the availability of raw materials. This restriction applies in particular to the conversion of sewage and landfill gases into electricity. The unique selling point of biogas, simple storage and power generation at peak times, is also not affected by this process of auctioning.

Thus, the only economically decisive factor on the South African energy market is the savings in own electricity consumption. The current electricity prices of around 1.20 rand/kWh (around 0.08 €/kWh) are low by German standards. However, the electricity price has multiplied since 2007: at that time, it was 0.013 €/kWh. In addition, annual price increases of 10% have been announced.

In this field of tension AKUT was commissioned by the Deutschen Gesellschaft für Internationale Zusammenarbeit (GIZ) GmbH to prepare two studies on the use of sewage gas for the two sewage treatment plants Kingstonvalle and Zeekoegat.

Economic plus ecological advantages

Against the current background of water scarcity in Cape Town, the relevance and explosive nature of the topic becomes very clear. The lack of rainfall is primarily attributed to climate change. The studies therefore identify emission reductions, in this case reductions in methane emissions, as a significant advantage in addition to economic advantages. At present, the gas produced by sewage sludge digestion is released into the atmosphere without further measures. This is now to be changed so that the gas is collected, processed and used for power generation.

The studies present detailed comparisons of various technical components, operating models and organisational forms. In both sewage treatment plants, the economic benefit can be maximised by optimising the utilisation of the existing digestion towers. Capacity utilisation is to be increased by adding so-called co-substrates, either digested sludge from neighbouring sewage treatment plants or waste from the agricultural industry. The latter could be identified by local AKUT employees so that specific modelling could be carried out, taking into account both the biogas potential and transport costs.

Economically reasonable are also the variants with an exclusive treatment of the sewage sludge of the sewage treatment plant. However, the then lower investments will lead to a slight reduction in profitability.

In addition to the technical components and the various operational management, operator models from in-house operation to BOT models were also examined. Two preference variants were determined from six different operator models.

The decision now lies in the field of politics. Should the measures be implemented? Which of the preferred variants is preferred? GIZ and AKUT are ready to continue to support the City of Tshwane and Mbombela municipalities – both in decision-making and in technical implementation.

The international IWA conference on sustainable solutions for small water and wastewater treatment systems (s2small2017) was held October 22-26 in Nantes, France. Florent Chazarenc (IMT Atlantique) chairman of the conference emphasized that small systems play a significant role in solving problems of humanity: „Small is beautiful, efficient and affordable – small is the future“ he said. More than 200 participants responded to the call and discussed their proposals for solutions in the areas of resource-oriented sewage systems, wastewater treatment and recycling.

As a German contribution to the improvement of small sewage treatment plants Heribert Rustige, AKUT partner from Berlin, presented the new DWA worksheet A 262 on the topic of constructed wetlands. This guideline is expected to be published in November 2017 and replaces the previous A 262 from 2006, whereas many new solutions and system variants have been added to the new worksheet. This includes the so-called French system, which consists of a combination with raw wastewater pre-treatment in a planted gravel filter and post-treatment in a planted sand filter (e.g. Phragmifiltre). Another newly described method using active aeration is particularly innovative. It was developed by Scott Wallace in the USA and extensively tested on site for several years in Germany by the UFZ research institute in Leipzig.

International Interest in the German Constructed Wetland Guideline

In the past, the A 262 had already attracted interest from other countries. It was last translated into Russian. Many users are now waiting for the release of the current version.  An English version will also be available soon from the DWA in Hennef.

The advantage of such a detailed set of rules is the increased safety for planners and operators. The worksheet specifies minimum requirements for the dimensioning of soil filters and refers to values derived from practical experience.  The user must check in each case whether the boundary conditions are correct in his application. In doing so, the regulations focus on the treatment of domestic and municipal wastewater, including combined sewerage systems. In addition, the treatment of grey water in soil filters is also taken into account.

The tables, which describe, for example, the different wastewater compositions or specific design values, are helpful. Various useful combinations of processes are shown. However, Rustige emphasized in his speech that the guideline is not a simple construction manual, as it requires specialist knowledge. No design formulas or modeling approaches are shown because they have not yet proven themselves in practice.

What is more interesting is the presentation of minimum requirements with which certain effluent values or performance degrees can be achieved. In the theoretical modeling of treatment efficiency, it is often not taken into account that hydraulics or oxygen transfer rates can be decisive limiting factors, which in the worst case can lead to a total clogging of the soil filter. It is better to orientate oneself on the statistically relevant results derived from practice, as they are used in the A 262.

The municipality of Theres, Unterfranken, Bavaria, was awarded the Bavarian Innovation Prize 2016.The new groundbreaking concept for the replacement of an aged waste stabilization pond which was developed by AKUT will obtain a natural way of treatment combined with an inexpensive way of operation.

The innovative design for the combined sewage treatment comprises a raw wastewater filtration wetland in the first stage and a nitrification wetland as secondary treatment.

Energy efficient wastewater treatment

In her laudatory speech the Bavarian minister for environment, Ulrike Scharf, accentuated the pilot character of the system for Bavarian municipalities in the rural area. She praised the possibility of high quality treatment without the requirement of electrical energy supply.

Standard technical treatment systems need extra energy for aeration, motor driven actuators and pumping.

In this case flow through wetlands is solely driven by force of gravity. The key technical component for establishing intermittent flow to the optimized filtration wetlands is a self-regulating mechanical siphon. The two siphons are capable of transporting even raw wastewater with high flow rates to both treatment stages. By floating the filter surface within a short period of time the best distribution and a maximum of natural oxygen input is achieved. No extra energy for aeration (aerobe treatment and nitrification) is consumed. These siphons are robust and minimize operational work. A model of this siphon was demonstrated at the AKUT booth in Munich at IFAT 2016.

Innovative wetland systems substitute inefficient waste stabilization ponds

The treatment of combined sewage in constructed wetlands in Germany is a virgin territory. For this purpose we can rely on tremendous expertise of our French neighbours. More than 3,000 so called “French Systems” with two-stage raw wastewater treatment are serving French municipalities. These systems have successfully suppressed conventional stabilization ponds because of their very good overall performance and stable operation conditions. 20% of these systems treat combined sewage.

The DWA expert group on small treatment systems has intensively checked the French approach. Together with experts from the research institutes IRSTEA and UFZ main design criteria have been fixed for separate and combined sewage treatment. The minimum surface area for treatment is 2 and 2.5 m² respectively. By describing these systems in the revised guideline for design, construction and operation of constructed wetlands DWA-A 262 (draft April 2016) a new boost for wetland technology in Germany is expected.

 

Foto (left to right): Prof. Dr.-Ing. Jens Nowak (AKUT Berlin), Price winner Matthias Schneider  (1. Mayor of Theres), Ulrike Scharf (Minister of Environment, Bavaria), Dipl.-Ing. Reinhard Müller (AKUT Hesse)

AKUT was prominently represented at the 1st African Biogas Forum in Nairobi.

The “African Biogas Forum” aimed to promote and support the sustainable development of the biogas sector in Africa, particularly Kenya. The Kenyan Cabinet Secretary Hon. Keter and the Deputy German Ambassador H.E. Deru launched the Forum. The event was supported by GIZ and the initiative “Renewables – Made in Germany” whose mission is to provide information upon the performance, efficiency and reliability of German renewable energy industry.

At our exhibition stand our Kenyan colleagues presented AKUT´s range of services in the areas of biogas, sewage and development cooperation. Additionally, our employee Mr. Dipl.-Ing. Romas Radtke gave a lecture about our various Kenyan projects: from the domestic small biogas plant via school energy stations with anaerobic digestion, wastewater treatment (aerobic / anaerobic) to industrial biogas plants, for example Kericho. The focus of his presentation was placed on the economics of small biogas plants and semi industrial biogas plants under the given economic conditions. He concluded that the production of biogas at most medium-sized farms with waste quantities of 5 to 15 tons per day was not economically feasible with the current fed-in tariffs. Exceptions to the rule are cases were the treatment of sewage / waste is in the foreground as biogas merely constitute an additional advantage here.

As a participant in the panel discussion “Biogas solutions”, Mr. Radtke presented various custom tailored solutions for AKUT´s customers illustrating our slogan “Customized Concepts for Environmental Technology”. Since 2006 AKUT is active on the Kenyan market. Intensive demand for an adjustment of the feed-in tariff for electricity from biogas has been emphasized. A working group of members of the biogas industry and customers is in charge to find solutions concerning this. The required increase to 15 US cents per kWh will allow a variety of projects that are not financially viable until now. Currently the market is limited only to customers with both: high volumes of waste and high energy demands as well. Through an appropriate feed-in tariff it will become more reasonable to produce power from biogas for the general market.

At the same time it became clear that the benefits of biogas in particular towards solar PV are not adequately addressed and promoted by policy makers.

It has been pointed out that compared to other Sub-Saharan African Countries the Kenyan market is already well developed – despite all limitations.

Starting in June 2016 our latest research project will investigate the benefits of various combinations of engineered treatment steps with constructed wetlands. In order to analyze additional elimination of trace organic compounds in the effluent of a wastewater treatment plant a pilot plant is going to be built at the wastewater treatment plant Schönerlinde (Berlin) in collaboration with Kompetenzzentrum Wasser Berlin (KWB – Berlin Centre of Competence for Water) and Berliner Wasserbetriebe (BWB). In this case an upstream ozonation stage will be combined with two different types of constructed wetlands. This combination has the objective to eliminate and reduce those persistent pharmaceutical residues which – without additional pre-treatment in wastewater treatment plants – would pass subsurface and surface flow treatment wetlands.

The project is part of a European research network named AquaNES. 30 partners in 10 countries will investigate on different focuses. Next to wastewater treatment systems the recycling of waters for drinking purposes through bank filtration and groundwater recharge are main components.

At the same time innovative measurement methods for quick detection of E.coli and antibiotic resistances shall be applied within the project. With new assessment methods and the development of decision-making tools including Life Cycle Assessment (LCA) and Ecosystem Services Analyses (ESA) planners and operators shall be supported.

At the first project meeting of all AquaNES participants, Valérie Bénard, Project Officer in the Environment & Resources Unit of the Executive Agency for Small and Medium-sized Enterprises (EASME), pointed out that high expectations are related to the project. After the ambitious and more than a year lasting procurement procedure with the identifier “Water-1b-2015” for innovative demonstration and pilot plants in the program Horizon2020 only 8 out of 160 proposals have been awarded and will be realized. The total budget of this project is going to be 10.7 million EUR, 73 % sourcing from public funding. The project is coordinated by Prof. Dr.-Ing. Thomas Wintgens, Institute for Ecopreneurship at the University of Applied Sciences and Arts Northwestern Switzerland.

Results of all sub-projects will be disseminated within the next three years (project timeframe until May 2019) in different publications which shall lead to broader application of best practices in the water sector.

AKUT is assigned to elaborate guidelines and manuals for planning and operation of well-functioning combinations of engineered wetlands with technical systems. Pilot plants of other partners are located in Rheinbach (Germany), Packington (England) and the Greek islands Antiparos and Thirasia.

From May 30 to June 3, 2016, our customers and business partners have the opportunity to meet us personally on the world`s leading fair for environmental technologies in Munich.

You find our exhibition booth in hall A 5 at the joint area of “Berlin Partner for Business and Technology” (booth No. 227/326). We are happy to present our latest products and innovations regarding treatment, recovery and drainage of rainwater and of wastewater from various sources (municipal, domestic and industrial). Once again this year’s focus is put on adapted, decentralized and small scale solutions in urban and rural areas.

A special highlight will be the live presentation of a self-priming siphon. This siphon works through hydraulic elevation (floating and sinking) without any external energy demand. A reliable start of a cycle doesn’t require auxiliary constructions and the siphon is designed for big amounts of potentially highly polluted sewage. This product may be an essential component of ideal solutions, e.g. in the reinforcement of sewage pond systems.

In order to fulfill latest requirements for the treatment of combined sewage most applied solutions are highly complicated in technological terms. The combination of a robust constructed wetland for combined sewage (regarding DWA-A 262, draft version 2016) with this siphon leads to optimized hydraulic efficiency whilst cleaning performance ranges from good to highly satisfying results. This solution makes it possible to comply with high requirements for the treatment of combined sewage. AKUT has developed this solution as an alternative to expensive and laborious network separation as the conventional solution for this challenge.

In case you are interested in these or similar, simple, cost-efficient and therefore (in the long run) sustainable solutions, we are happy to consult you at our corner booth No. 227/326 in hall A5.

We offer consultancy about our broad range of services, including the generation and capture of biogas out of domestic wastewater or organic substrates, energy saving and energy input of electricity and heat into semicentral grids, SBR technology as an upgrade of pond systems and last but not least sustainable sanitation systems (e.g. ECOSAN or NASS: DWA-A 272). You may feel free to arrange an appointment with us at IFAT beforehand. In this case we can issue entrance tickets to visit our stand. Contact us for appointments and tickets: 0049-30-52000950