Discussion on options and performances of advanced control sys-tems for biological nitrogen removal after advanced primary treatment. The process control options are described in details as well as process performance in the demo site was quantified in-cluding transition strategy from conventional scheme to process with the advanced carbon extraction.

Producing more biogas from sludge digestion is one of the main factors to reach energy-neutral or energy-positive WWTP operation. In the project POWERSTEP a primary goal is to remove as much energy rich primary sludge as possible from the system prior to the biological treatment without having negative effects on downstream processes and effluent quality in terms of nitrogen removal. Within the project Work Package 1 addresses enhanced carbon extraction in primary treatment with different filtration technologies (drum and disc filters from Veolia Technologie AB - Hydrotech) tested in Case Study 1 (Westewitz, Germany) and 2 (Sjölunda, Sweden). To give scientific proof of the results and benchmark the performance against other competing technologies, process performance data has to be compared with other technologies used for primary treatment. In this report the results of literature research and comparison with data of case studies of full scale enhanced primary treatment units are shown and compared to each other. Specific indicators for the comparison are defined followed by identification of available alternative technologies for primary treatment at municipal wastewater treatment plants (WWTPs). These technologies are described by functionality, efficiency and operational data. Finally an overview of the results is presented in form of a fact sheet for primary treatment processes.

This deliverable describes Guidelines for design and operation of advanced primary treatment with microscreen. Technical speci-fications including pre-treatment, mesh size, hydraulic velocity, chemicals (substances, doses, contact times), operational re-quirements (backwash, cleaning) and operational performanc-es (removal rates, backwash sludge quantity and quality) are presented with data gained from the two Case study site trials in Westewitz (Germany) and Sjölunda (Sweden)..

This study was done in connection with the EU-funded project POWERSTEP. Powerstep, with various research-work packages, is positioned to help conceptualise waste water treatment facilities as energy suppliers. The goal of the study is to evaluate if micro-filtration, as part of an expanded pre-treatment stage, can provide organic matter for digestion while allowing stable treatment conditions in sludge activation.

One aim of the EU-funded research Project POWERSTEP is to investigate the applicability of duckweed in wastewater treatment in removing nitrogen based on the principle of the APS duckweed plant system. The motivation for this investigation is the intended combination of the Hydrotech drum filter with the APS duckweed plant system at case study one of the POWERSTEP project. The goal is to demonstrate and market a new wastewater treatment concept heading towards energy positive wastewater treatment plants. The investigations were first carried out on a laboratory scale to identify suitable duckweed species, the optimal duckweed mat density, relative growth rate (RGR), doubling time and the ammonium removal under the given conditions at the case study. Subsequently, the results were used to test on a large scale on a sewage treatment plant. From the four tested duckweed species Lemna Minor, Lemna Minuta, Landoltia Punctata and Spirodela Polyrhiza, the species Lemna Minor and Landoltia Punctata adapted best to the given wastewater composition. In a mix population of Lemna Minor and Landoltia Punctata a mat density of 0.075 g· cm-2 was determined to be best in suppressing competitive submerged algae growth and enabling duckweed relative growth rates of 0.072 d-1 and doubling times of 9.93 days. Based on the APS duckweed plant system, mean daily ammonium removal of 0.56 g N· m-2d-1 and a daily ammonium degradation efficiency of 72.75% to a mean ammonium effluent of 12.26 m·l-1 was shown at a lab-scale for a retention time of 24 hours. Based on the results of this research, it can be concluded that the principle of the APS duckweed plant system under the use of Lemna Minor and Landoltia Punctata can be applied to remove ammonium from wastewater achieving high reduction rates. The experiment on the wastewater treatment plant shows that the effectiveness of the purification process is heavily dependent on climatic conditions. For example, in the summer the duckweed had a total nitrogen(TN) removal rate of 40-70%, while in winter it was only 17-40%. There were also great difficulties due to the occurrence of heavy storms. The plant switched off and was destroyed in many places which led to a dying of duckweed. There were also problems with the harvest of duckweed. Due to poor flow conditions, duckweed was not easy to clear off and could not be harvested.

As in most of the cities around the world, in the last 30 years Latin-American ones have focused on investing in building infrastructure to provide sewer and water services to the communities. However, these infrastructures are going aging day to day. The municipalities need to extend management activities by the development of support tools such as deterioration models to face the aging problem. In the literature of sewer asset management, SVM has been a useful tool to predict and forecast the structural condition of pipes. In this work, the use of differential evolution method as optimization tool was implemented to find the optimal hyper-parameters for SVM models. The SVM models were applied in the main cities of Colombia (Bogota and Medellin) given as a result that the optimized SVM model provides less than 5% of deviation in the prediction of structural conditions in both cities.

In order to reduce energy requirements of wastewater treatment plants, sludge disintegration in form of thermochemical hydrolysis is considered as an alternative method for sludge treat-ment. It is supposed to improve biogas yield by means of improved biodegradation, thus in-creasing energy production. However, accumulation of persistent organic matter has been re-ported as a result of thermochemical hydrolysis. To examine the effects, thermochemical hy-drolysis of excess sludge and thickened excess sludge has been carried out in the laboratory in the temperature range of 50 °C to 90 °C with a base addition of 0,02 gNaOH/gTS to 0,08 gNaOH/gTS. The treated sludge was then analysed in biomethane potential tests regard-ing its biogas yield and in Zahn-Wellens-Tests concerning the accumulation of persistent or-ganic matter. Due to complications in both experiments a methodology which solved these issues had to be developed first. Only the experiments done after the completion of this meth-odology were evaluated. The biomethane potential test resulted in an increase of biogas yield in nearly all tests. Optimal conditions were found at 70 °C and with 0,08 gNaOH/gTS with an increase of 26 % in biogas yield to 272 NmL/g oTR. Only one Zahn-Wellens-Test could be fully evaluated due to foaming problems. The treated sludge showed an increased formation of refractory COD from the initial VS of the samples. The conversion factor rose with an increased base addition. 3,15 % of VS of the untreated sample were converted into refractory COD, whereas it was 5,15 % for the sample treated at 70 °C and with 0,08 gNaOH/gTS. To obtain generalizable statements for wastewater treatment plants, foaming problems should be re-duced and further experiments carried out to verify the found results.