Pakistan is home to bustling cities like Faisalabad, Karachi, Lahore and Multan which are not known to be the fastest growing metropolises that contribute significantly to the economy of the country. One would expect such cities to have their basic civic facilities such as water supplies networks and sewerage lines in order.
In almost every city, one comes to witness disgusting sewerage waste overflowing from lines and inundating on various lanes and prominent streets. It goes without saying that aside from the unbearable stench that these spillage results in and the difficulties commuters face, this sewerage water poses serious health hazards to the public. Stagnant sewerage water on the streets and the potholes on roads are just the tip of the iceberg, so to speak, when it comes to the hazards these spillages pose.
There have been numerous reports of young children drowning after falling into open manholes because it was not visible due to the stagnant water surrounding it. People have been electrocuted whilst stepping into the water because the water had seeped into underground electrical cables. What is even worse is that this sewerage water has been known to corrode underground sweet water lines and contaminating it resulting in a host of health problems for hospitals and people living in the area. Government authorities such as KWSB or WASA, including local government bodies, either turn a blind eye to these sewerage problems, or announce that concerned departments are looking into the matter and then it is forgotten as time passes by until someone raises hue and cry over it once again. Such is the sad state of affairs that it took a viral picture on the online social media of a funeral procession passing over sewerage water for authorities to take notice of the abysmal state of sewerage lines in a city in Punjab!
The important thing here to understand is that the underlying problem is not of sewerage water spilt out on to streets but the entire sewerage lines network and the obsolete materials they are built from. The sewerage lines network of every major city in Pakistan is currently based on pipes made from Reinforced Concrete Cement (RCC) or Asbestos Cement (AC). Millions of rupees have been allocated for repair work and replacement of lines, yet there is no improvement in the system because recommended piping material was again either RCC or AC/pipes.
The foremost disadvantage with using RCC & AC pipes for sewerage lines is that they easily corrode at the crown because of chemical reactions inside the lines. Decomposed organic matter present in the sewerage release heavy amounts of a gas called Hydrogen Sulphide. This Hydrogen Sulphide reacts with the Oxygen in the air to form Sulphuric Acid. Sulphuric Acid is known to be one of the most potent acids on the planet. This Sulphuric Acid then reacts with the cement with which the pipes are made from and corrode them from the crown over time (Crown Corrosion). Eventually these cement RCC pipes collapse leading to the silt and debris reducing the carrying capacity of the pipes which consequently leads to sewerage water seep into the earth and spill out on to the streets via manholes.
The simple and extremely effective solution to this problem is the cheap alternate material known as Polyvinyl Chloride, commonly known as PVC. These pipes can be used not only for internal drainage works in homes, but also for the external larger diameter main sewer lines too. In Pakistan there are now several large scale manufacturers of PVC pipes that are currently producing small and large diameter PVC pipes in various sizes for use in drainage and sewerage lines.
These PVC pipes are perhaps the best alternative to RCC and AC pipes for use of sewerage pipes. They are highly resistant to corrosion from acidic materials; they are light weight, tough and rigid. Furthermore they can be deployed, joined, transported, repaired and maintained at a fraction of the cost that it takes to do the same with RCC and AC pipes.
In conclusion, with the replacement of the obsolete and most vulnerable RCC / AC pipelines with PVC, one can expect the sewerage problems to significantly reduce. Not only will the revamp provide a much needed relief to the mass public, the livelihoods of the people, the utilities and transport systems of the cities but also reduce the impact the obsolete RCC pipes network has on the national exchequer.