KARACHI, Dec 26: Almost all households around the three Sewage Treatment Plants (STPs) believe that the pollution of water environment in the city is a serious issue and that the treatment of sewage is important to improve the “water environment as well as living environment”, said a survey report.
The Japan International Cooperation Agency undertook an environmental and social impact survey of all the three existing STPs of the city.
According to the survey report, most of the households located in the vicinity of the three STPs also said that the collected sewage should be treated properly at the plants and they were willing to pay for it while some of those residing around STP-II located at Mehmooodabad claimed that some graves were still inside the plant's site.
The three sewage treatment plants of the city are treating sewage much below their designed capacity. The STP-I, situated at Haroonabad with a designed capacity of 51mgd, is treating only 20mgd; the STP-II, located at Mehmoodabad with a capacity of 46mgd, is treating zero while the STP-III, situated at Mauripur, is treating just 35mgd against its designed capacity of 54mgd.
Though the city is producing 472mgd sewage, only 12 per cent of the total raw sewage, which comes to 55mgd, is being treated while one per (6mgd) is being used by farmers. And, as such, a huge quantity of 411mgd untreated sewage, which comes to 87 per cent of the city's total raw sewage, is being discharged directly into the Arabian Sea, causing filth at beaches and harming the marine pollution. According to the survey, 35 per cent of the households around STP-II also thought that the odour from the STP is a problem. The households located close to the north boundary of the STP-II are significantly affected by the smell.
However, because the most of the households seriously affected were within 100 meters distance from the boundary of the STP, the intensity and travel distance of the smell from STPs seemed to be limited, the survey report said, suggesting that in future, smelly facilities of the STP should be located at the far side of adjacent residential areas if it was not avoidable to construct STP close to the residential areas.
Besides, it is also important to adopt wastewater treatment technologies that do not cause strong smell. If possible, new STPs should be constructed at least 100 metres away from the residential area, the survey report added.
It was further pointed out that almost all the sampled households already have sewerage connection to gutter lines, but about 80 per cent of those sewerage users have complains on the sewerage system in the city, mainly about clogging and overflows.
Social considerationAbout 95 per cent of the households around the STPs thought that their STPs contribute to the improvement of life and environment in the city while 70pc of the households felt pride that their areas contribute to environmental protection with their STP.However, many of the households, which are adjacent to STP-II (Mehmoodabad) and along with nullah used as its discharge point, are not proud of their contribution with the STP-II.
It also pointed out that about 10 per cent of the households thought that the STPs had changed the social and commercial value of the surrounding land. Some households pointed out the positive value of the current reuse of effluent from STP-I, located at Haroonabad, for park maintenance and agriculture and a possible increase of land value due to STP-III.
However, some households around the STP-II pointed out the decrease of land value due to the influence of the STP, including its foul smell.
Although 40 per cent of the households neither understand nor accept the reasons why the STPs was constructed there, only about 10 per cent of the households felt unfairness that their area had the sewage treatment plant.
Environmental considerationsEight per cent of the sampled households around the STPs had noticed any environmental impact of the STPs. Some of them answered that greenery had been increased in their areas because of the reuse of wastewater.
Besides, some of them were also aware that sludge from the STPs was partly used for agriculture purpose.
However, during the survey some of them replied that their STPs were causing pollution and mosquito problems. About 20 per cent of the households also thought the landscape had become less beautiful due the STPs.