Biological anaerobic treatment: the way forward

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ONCE PAKISTAN was a water-surplus country, but today it is a water deficit country. The water availability started decreasing from 5,600m³ per capita at the time of independence to 1,299m³ per capita in 1996-97, while in 2006 it further decreased to 1,100 m³ per capita, currently it is estimated 950m³, and projected to less than 700m³ per capita by 2025. Therefore, search for other non-conventional water resources i.e. wastewater treatment for daily use and irrigation has become most important. Generally in Pakistan, industrial and domestic wastewater is being discharged directly into; sewer system, natural drain, water body, or to internal septic tank. Mostly, this wastewater is treated neither on government level nor on private. There are very few wastewater treatments plants in the country, but their capacity and efficiency are questionable. Most of untreated wastewater is being used for irrigation, directly or indirectly. This is creating ill effect not only on soil in term of physical and chemical properties, but also contaminating food chain and causing health related issues. There is very limited information available in this regard, even we dont have effective national policy on sustainable use of wastewater. About treatment and disposal of wastewater, laws and regulations have been formulated in our country but due to lack of their implementation these are not effective which is becoming the real issue. The quality of ground and surface-water is also becoming low due to unchecked disposal of this untreated disposable municipal and industrial wastewater which further worsening the situation. Another reason for deteriorating of water quality is excessive use of fertilizers and pesticides. This situation needs a low-cost treatment option for wastewater especially municipal wastewater treatment through which the wastewater can be safely used for agricultural purposes. Municipal wastewaters have a broadly similar composition with regard to their content of organic matter and nutrients except their microbiological characteristics. To use wastewater for agricultural irrigation, it is important to select wastewater treatment processes that both reduce pathogen numbers and retain the nutrients, and at the same time that reduce pathogen levels before using it for crop irrigation. In recent years, the most promising methods, that is, anaerobic bio-reactor (ABR) treatment and other related treatment systems. The outstanding characteristics of high rate ABR include the anaerobic microorganisms capable of aggregation, low operational and maintenance costs, energy recovery in the form of biogas, low energy consumption, and low production of digested sludge. In developing countries like India, Brazil, and Colombia, where financial resources are generally scarce due to high energy costs, this process is familiar as one of the most feasible methods for the wastewater treatment. Therefore, a well-coordinated program for biological anaerobic treatment is necessary to create awareness among different sections of the society including the general public, organizations, industrialists and farmers.


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Published in: Volume 06 Issue 33

Short Link: http://www.technologytimes.pk/?p=14059