Wastewater Mismanagement and Its Environmental Impacts (A Case Study of Islamabad Zone-1)

Abstract

The residential, industrial, and commercial zones of Islamabad generate about 55 million gallons of wastewater and over 600 tons of solid waste per day. The objective of this study was to identify various sources of wastewater and measures taken by the Capital Development Authority (CDA) to manage the wastewater in Zone I of the city. Twenty-five sectors of zone - I generate nearly 31 Million Gallons per Day (MGD) of wastewater. The study investigated the impact of wastewater mismanagement on surface and groundwater quality. Standard Operating Procedures (SOPs) of the World Health Organization (WHO) were adopted for sampling. Master plans of water supply and centralized sewerage network (CSN) of zone I were officially subscribed. All these maps have been reproduced/overlaid and gridded with the help of Arc-GIS software. A ground survey of four Sewerage Treatment Plants (STPs) was carried out. Ten representative samples of surface & groundwater were drawn from different sectors of the zone - I and analyzed at PCRWR lab for TSS, BOD CDO It was observed that surface and groundwater resources were severely polluted. The levels of TSS, BOD, and COD in the industrial-cum residential area are found as high as 1100 mg/l, 445 mg/l, and 575 mg/l respectively. Whereas, in residential areas corresponding levels were 450 mg/l, 230 mg/l and 360 mg/l against predefined NEQs limits of BOD 80 mg/l, COD 150 mg/l and TSS 80 mg/l respectively. The impact of wastewater percolation into groundwater has been analyzed and 3 out of 10 tube wells were found with bacteriological contamination as high as 11 Coli-forms MNP/100 ml. Kendal rank correlation has applied to reject null hypothesis of the independence between wastewater management and population growth in zone Islamabad. I of There is only one Centralized Sewerage Network (CSN) in the zone - I with four Sewerage Treatment Plants (STPs). The current efficiency of CSN for wastewater collection and safe disposal is just 14% and rest of 86% wastewater diverted into 32 natural water channels/nullahs. The existing wastewater treatment capacity of these STPs was observed to be underutilized 6 to 7 MGD, instead of their actual design capacities around 17 MGD due to malfunctioning to CSN. The population in zone - I has increased by 72% in last ten years with annual migration rate of 6%, which caused rapid urbanization and rapid population growth in zone I of the city, where large number of inhabitants directly consume groundwater, which is chiefly supplied through over 100 tubewels. It is conlcuded that wastewater mismanagement is a potential threat to surface and groundwater quality and to the public health.