Protecting drinking water from corroded pipe at the municipal level
Above: Corroded pipe in Marktheidenfeld led to increased need for disinfectants.
Like many cities across Europe and the U.S., the city of Marktheidenfeld, Germany, saw significant growth in its water infrastructure throughout the mid-20th century. From 1930 to the end of the 1950s, Marktheidenfeld invested in more than 250 miles of water distribution pipe made from unlined cast iron and steel. Unfortunately, it was later discovered that pipe made from these materials corrodes over time. The resulting decline in the city’s water quality was largely due to the extensive need for higher amounts of disinfectants and their resulting byproducts.
Seeking a new solution to its corroded pipe and disinfectant use that would not require a rebuild of the city’s piping system, Marktheidenfeld turned to Folmar Pipe Protection technology, which is now licensed in the U.S. through Great Water Tech. The city agreed to a three-year study of the technology with three goals in mind: maintaining disinfectant residual levels with reduced disinfectant consumption, improving distribution system resilience and improving water quality for the city.
Folmar Pipe Protection is a proprietary silicate-based mineral solution that prevents corrosion, scale, metal leeching and the formation of disinfectant byproducts throughout water infrastructure. The formulation creates an ultra-thin, super-hard “glass” layer on the interior of the pipe wall, separating metal or cement piping from water. In addition to preventing corrosion and contamination, it fills and seals small cracks, maintaining the integrity of the piping system while eliminating friction in the delivery process.
In a three-year trial study, Marktheidenfeld tried a new pipe corrosion protection technology and monitored its effects on water quality.
Pipe Corrosion Problem
Unlined cast iron and steel pipe comprise about 80% of the 255 miles of water pipeline in Marktheidenfeld. The remaining pipelines were ductile iron, PVC or asbestos cement. The large amount of unlined cast iron and steel pipe created significant disinfectant demand in the distribution system.
The disinfectant demand came from two sources. The first was bulk water consumption. Disinfectants reacted with organic and inorganic contaminants in the water. The second demand came from corrosion of pipe wall surfaces. Disinfectants reacted with corrosion products, oxidizing dissolved iron (coming from the pipe surface), biofilm on the pipe surface, and organic and inorganic contaminants that accumulated within the corrosion product biofilm mixture.
As a result of the corroding pipe, customers complained about objectionable taste, odor, color and particles in their water. Folmar Pipe Protection helped mitigate these problems by creating a new protective seal around the inside of Marktheidenfeld’s piping system.
Pipe Coating Study
To evaluate the effectiveness of the technology, an isolated area of 2 sq km was selected to study the effects of the product. This area was chosen because it was representative of the rest of the distribution system, with a similar composition of piping materials and relative water flow.
The water used in the study was drawn from five wells and treated with Folmar Pipe Protection at the source. The only other treatment was disinfection by free chlorine at 0.1 to 0.3 ppm.
After chlorine dosing, the Folmar Pipe Protection solution was added to each water source plant’s effluent line at an initial rate of 10 grams per cu meter, which was reduced to 5 grams per cu meter after three months.
To evaluate changes in water quality, a number of parameters were measured regularly at five primary distribution system locations, each representing one of the plants. The same parameters also were monitored at each of the groundwater wells and 25 other locations within the water distribution system.
At each of the distribution system monitoring sites, Folmar Pipe Protection was measured weekly and microbiological tests were monitored monthly to determine bacterial activity.
Background data were collected three weeks prior to the startup of the pilot study at four of the five primary distribution system locations.
Less Chlorine, Less Corrosion
After 36 months of studying the effect of the new technology, the Marktheidenfeld water system produced encouraging results. Flushing volume dropped by 98% after the solution was put into use. Additionally, customer complaints to the water management companies dropped by 98%. Chlorine dosing rates dropped by 40%, in addition to an 85% drop in microbiological levels.
Over the three-year study period, the results showed improvement in all measured water quality parameters. Customer complaints dropped, microbiological levels improved, demand for disinfectants was lowered, less corrosion was observed, less biofilm accumulated, the water was odorless and colorless, flushing was nearly eliminated, and overall water quality improved.
Additionally, reduced friction resulted in energy cost savings for Marktheidenfeld.