Zero Liquid Discharge and Recycling of Paper Mill Industrial Wastewater via Chemical Treatment and Solar Energy in Egypt

Document Type : Original Article


1 Water Pollution Research Department, Environmental Research Division, National Research Centre

2 Solar Energy Dept, National Research Centre, Dokki, Cairo, Egypt


Integrated treatment for recycling of industrial wastewater has become an urgent necessity at the present time. Zero Liquid Discharge (ZLD) in combination with solar energy become urgently needed not only to compensate water shortage but also to preserve the recent water resources from pollution. In this work where the waste-paper was collected to be recycled; an integrated system has been applied for wastewater treatment to reuse in process, while the rest is being comply with the regulatory standards to be discharged from the paper factory. Treatment including a lot of coagulants such as alum, ferric chloride, lime and cationic polymer these coagulant used separate or combined .The removal efficiencies of Chemical Oxygen demand (COD) were 84%, 83.5%, 75% and 79.4%, respectively. Consequently Total Suspended Solids (TSS) removal efficiencies were 99.5%, 99.6%, 97.5% and 98.9%. All treated industrial wastewater can be recycled to fulfill the phenomenon of ZLD. On the other hand, the negative impact of produced chemical sludge was diminished via non-conventional technique as a clean post treatment, where an effective design of a solar dryer was used to obtain dry sludge cake and to collect a highly purified water to be recycled in industrial process. Solar energy showed good potential in drying the sludge paper with competitive cost and clean environment. It is found that each square meter of drying surface area can dry 9 kg of wetted sludge paper per day. The presented trapezoidal shape solar dryer can dry daily up to 540 kg of wetted sludge paper. Based on the required sludge paper water demand, a large scale solar dryer can be sized accordingly.


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