Door water verbonden
In 1920, when N.V. PWN Water Supply Company North Holland (PWN) was founded, the demand for drinking water was satisfied by ground water extraction. However, caused by the growing drinking water demand PWN was compelled to utilize surface water as an additional source. Therefore in the 1960's water treatment plant Andijk was constructed for the direct production of drinking water from IJssel Lake (River Rhine) water. Originally the plant consisted of microstraining, breakpoint chlorination, coagulation, sedimentation, rapid filtration and post disinfection. Since 1978 the plant was upgraded with a pseudo moving bed GAC filtration followed by an additional microstraining.
After about 40 years of operation, wtp Andijk stilt complies with all European Community and Dutch drinking water standards. Nevertheless a retrofit is desired in view of by-product (THM) formation, barriers against pathogenic micro-organisms such as protozoa and control of organic micropollutants such as pesticides, endocrine disruptors and pharmaceuticals.
PWN has pursued the application of UV/H2O2 treatrnent for both primary disinfection and organic contaminant control followed by the already present GAC filtration for rernoval of residual H2O2, AOC and nitrite with very promising results. UV/H2O2 is operational since late 2004.