Waste-waste treatment technology and environmental management using sawdust bio-mixture

AbstractThe industrial wastewater (WW) of potato-chips factory is characterized by its high biological oxygen demand (BOD) and chemical oxygen demand (COD), in addition to a medium content of oil & grease (O&G), total dissolved slats (TDS) and total suspended solids (TSS). A new technique for wastewater treatment has been applied using bio-mixture of selected strains of Aspergillus terreus or Rhizopus sexualis in addition to the natural flora of sawdust (SD-BIOMIX) in the form of mobile micro-carrier in activated sludge system. Different kinds of composted sawdust were used as a microbial carrier, support and source of nutrients and enzymes to enhance the wastewater treatment process; in order to improve the quality of treated wastewater and resulting sludge. The parameters of treated wastewater in terms of BOD, COD, O&G, TDS and TSS were greatly improved by 85.0, 79.0, 82.7, 74.6 and 87.7% respectively, in relation to the retention time and kind of tested materials. The 14 days microbial–treated (composted) sawdust by A. terreus, or R. sexualis as (SD-BIOMIX) exhibited the highest enzymes contents and was the most efficient materials for the wastewater treatment process in comparison with commercial biomixture products e.g. C157 and EM solution. Furthermore, the retention time of the treatment process could be reduced to 4 hr only. Finally, the resulting sludge(s) of (SD-BIOMIX) was easy to separate (in 5–10 min.) from wastewater. The sludge, according the chemical analysis, can be safely used in agriculture as an organic fertilizer and soil conditioner. In addition, different kinds of resulting sludge have been tested as biosorbents and exhibited high ability to remove chromium (89.1 – 99.3%), nickel (84.3 – 98.0%) and zinc (85.6 – 97.7%) from the heavy industrial wastewater. Data indicated the possibility of magnifying the introduced (SD-BIOMIX) as a new technique for the treatment of wastewater and as new trend for wastes management and pollution prevention and could be applied in Kingdom of Saudi Arabia as one of advanced biotechnology to solve many of environmental problems in KSA