M. Dohmann

Thematic issue: water of the Erhai and Dianchi Lakes

Eutrophication of surface waters is a severe problem worldwide (Dimberg and Bryhn 2014; Harmon et al. 2014; Christia et al. 2014; Renjith et al. 2013; Sedlacek et al. 2013; Antunes et al. 2013; Rinke et al. 2013; Watchorn et al. 2013; George et al. 2013; Ivashechkin et al. 2004) but particularly important to China because of the use of water resources from the huge rivers originating in the Tibetan plateau flowing through the North China Plain into the Pacific Ocean. The water quality issue includes nutrients (Ji et al. 2014; Wu et al. 2013) and phosphorus (Chen et al. 2014; Yuan et al. 2014; Zhu et al. 2013; Liu and Chang 2013; Marjore et al. 2013). Recent thematic Issues in EES were dealing with Integrated Water Resources Management under different hydrological, climatic and socio-economic conditions (Kalbus et al. 2012; Grathwohl et al. 2013) including topics like progress in monitoring and modelling concepts (Beinhorn et al. 2005; Beyer et al. 2006; Kalbacher et al. 2012; Rink et al. 2012) and the aquatic ecosystem functions (the harm of microcystis aeruginosa, role of macrophytes in ecological water treatment (Li et al. 2015a, b, c), see below). ‘‘Microcystis aeruginosa is a species of freshwater cyanobacteria which can form harmful algal blooms of economic and ecological importance (Huo et al. 2015). Microcystis are the most common toxic cyanobacterial bloom in eutrophic fresh water. Cyanobacteria produce several groups of toxins, neurotoxins and peptide hepatotoxins, such as microcystin and cyanopeptolin’’. Several case studies have been reported recently in EES. Huang et al. (2014) investigated algal bloom and factors influencing its formation in Taihu Lake from 2000 to 2011. Thi Thuy et al. (2014) studied the occurrence of cyanobacteria and microcystins in the Hoan Kiem Lake and the Nui Coc reservoir (North Vietnam). Macrophytes are aquatic plants that grow in or near water and are emergent, submergent, or floating. In lakes and rivers macrophytes provide cover for fish and substrate for aquatic invertebrates, produce oxygen and act as food for some fish and wildlife. Several case studies have been reported recently in EES from Brazil, India and Greece. Goldoni et al. (2014) investigated cytotoxic and genotoxic evaluation and chemical characterization of sewage treated using activated sludge and a floating emergent-macrophyte filter in a municipal wastewater treatment plant in Southern Brazil. Christia et al. (2014) studied seasonal and spatial variations of water quality, substrate and aquatic macrophytes based on side scan sonar, in an eastern Mediterranean lagoon (Kaiafas, Ionian Sea). Anshumali et al. & Olaf Kolditz ees-editor@ufz.de

German contributions to the Major Water Program in China: “Innovation Cluster–Major Water”

Within the German research initiative CLIENT (International Partnerships for Sustainable Technologies and Services for Climate Protection and the Environment that is funded by the German Federal Ministry of Education and Research, BMBF), several projects started recently to support China in solving the water problems in selected areas: SINOWATER (Dian Lake and Liao River), SIGN (Tai Lake) and Urban Catchments (Chao Lake). These German–Chinese cooperation projects by BMBF and the Chinese Ministry of Science and Technology (MoST) officially started with the inauguration event held on 7 May 2015 in Beijing where a joint declaration between the Chinese and German ministries was signed.

Operational problems of wastewater filtration plants — their analysis and possible solutions

During the last 15 years, mechanical-biological wastewater treatment plants in Germany have been increasingly supplemented by filtration plants. Their technology, which is based on the one used for drinking water processing, had to be adapted to the differing circumstances. Companies specialised in filtration, as well as engineering offices are planning these plants. Workers at wastewater treatment plants had to learn how to operate the filters. Not all the necessary adaptations went smoothly. A number of operational problems have occurred during the last few years. Some problems have been analyzed by the Department of Environmental Engineering of the Aachen Technical University (ISA), leading to suggestions for avoiding these mistakes in the future.