Cleanblock to Treat Polluted River Water Short general project overviewIn Indonesia, approximately 98% of household and industrial wastewater is discharged without treatment into rivers, streams and the sea. Households and industries close to a water body discharge their water directly into this water body. Furthermore water bodies are generally used as dumpsites for solid waste. As a result surface waters in Indonesia are highly polluted. This project is a feasibility study to see if the Cleanblock solution can treat part of these streams in a very practical way and to develop the business case in Indonesia. Cleanblock has proven capabilities to both filter and biologically treat waste water; it is porous and has filtering capabilities. 4 Cleanblock filters will be installed: 2 in transboundary streams in Tangerang and Tangerang-Selatan (West-Jakarta), 2 in Bandung and Kabupaten Bandung. The streams in Tangerang are in the Jakarta Bay basin and the other 2 are part of the Citarum basin. Highly polluted water will run through the filter for direct treatment and the outflow will be significantly cleaner.Initial activities and results of the projectThe project starts with an inception phase with desk & field studies to get a clear insight in the test locations (water quality, discharge etc). The monitoring plan will be developed, and the preparation of the test locations will be done (ordering of materials, detail designs, import of Cleanblock). Then the implementation and constructing of the filters is expected, with water results testing every 2 weeks. The filters will be adjusted to measure the impacts, and an efficiency optimization will be done to minimize the changes of clogging (solid waste). The results will be analysed, and conclusion will be drawn; is Cleanblock financially and technically feasible? Can this be scaled up?What makes the technology, product, method or approach used innovativeCleanblock is a 100% natural and environmental friendly product. It is inert and cannot be biologically degraded. The material is made out of basalt and its structure cannot change. The blocks can be fully recycled. In the Netherlands the entire chain is connected and Drainblock is a circular economy product. The blocks contain 40% recycled stonewool. Drainblock has a porosity of 98% and can store almost its entire volume in water. It holds water against gravity which is extremely useful in hilly areas (red: water is stored upstream rather than running down to the lowest point).The porosity is not only great for water storage (95% of its volume is stored in water), but also for bacteria colonisation. Cleanblock has proven to be an effective medium for biological treatment in controlled conditions. In septic tanks the material has been used for over 25 years. The blocks last for over 15 years without maintenance. The leachate that comes out is good for re-use in agriculture. Efficiency is 98% for BOD and COD.What are the results of the projectCleanblock filters were installed at 6 different locations in Bandung (2), Kabupaten Bandung (2), Bekasi and Depok. ITB Bandung (University) has done research on the results and they conclude in their paper the following:The average removal efficiency by artificial supporting materials is 52% COD, 31% TP, and 39% NTK. Material type II with cube size provide the best removal efficiency among other material variations. The average quality status of Cikapayang River is improved after the addition of artificial supporting material. The ability of the material to remove organic materials and nutrients in water bodies has increased during dry season. The removal efficiency increases following the concentration of pollutant parameters in the water body increases. The allowance kinetics tend to be first order for COD and TP parameter, while second order for NTK. Based on these result, mineral wool as an artificial supporting material can remove organic materials and nutrients and improve the quality of water bodies.The improvement on the smell and colour was good. For all visitors it was a very clear added value as the ‘sewage’ type of smell had disappeared behind the filters. The colour of the water also improved, but due to the colour of the concrete and deposits it is harder to see. Results in dry season were beyond expectation. In the last edition of the filters Cleanblock focused more on improving colour as well. They used ‘home-made’ charcoal and a special material ‘filtralite’. The results were very good with filtralite being significantly better in the industrially polluted waters.