Cost-benefit analysis of using treated sewage for landscaping in Lahore city, Pakistan

摘要

In Pakistan, wastewater production is 4.43billion m(3)/year. The best way to deal with this problem is to reuse water in irrigation of crops and gardening, after proper treatment. Wastewater reuse for landscaping is practicable in Lahore because high quality water is not necessary for landscaping purposes. Wastewater was treated at lab scale to reuse for landscaping in Lahore for cost-effective algal treatment to reduce the cost with analysis of Algal species Sirogonium sticticum and Chaetomorpha sutoria effectively removed the phosphates (99.9%), sulfates (99.6%), nitrates (100%), coliforms (99%), and color (92.8%), etc. After the reduction of chemicals, percentages of color (92.8%) and all physical and chemical parameters are within the current law in Pakistan. It was estimated that the total energy cost of landscape irrigation for Race Course park, Lawrence garden, and Gulshan-e-Iqbal park was about USD 86,409.72/year and average cost of fertilizers for landscaping in major parks of Lahore is USD 1,528.49/year. Reusing of this wastewater can save this cost in addition to the saving of almost five cusecs of drinkable fresh water. The cost of collecting wastewater in oxidation ponds is very less because most of the drains pass through these parks, and pumping water through these drains requires very less economic consumption.