62
N. M. Jais et al.
meet the relevant environmental standards before final disposal into the rivers or lakes
(Karia and Christian 2006; Jais et al. 2016). On the other hand, the system should
be designed and constructed according to the engineering standard, for example the
concrete strength and suitable maintenance (Karia and Christian 2006).
4.4 Fresh Wastewater Treatment System
The wastewater treatment system is designed under several stages which are preliminary treatment system, primary treatment system, secondary treatment system and
tertiary or advanced treatment system. Preliminary treatment system is a method to
remove large inorganic particulate contents of wastewater or floating materials that
disturb the operation in primary and secondary treatment of wastewater. The preliminary treatment system includes bar screen for screening large floating materials
while grit chamber for heavy suspended solids. Some of the preliminary treatment
systems have skimming tank to trap oil and grease which is suitable for fresh market
wastewater. The primary treatment system aims for the separation of solids through
sedimentation or settling process in sedimentation tank. The wastewaters are left
in the tank for several hours to allow the particles to settle at the bottom of the
tank. The settleable suspended solids which are called as sludge are then removed or
drawn from the tank. This sludge may reduce 60–70 % of fine settleable suspended
solids which include about 30–32 % of organic suspended solids (Karia and Christian
2006).
After primary treatment, the biological treatment known as a secondary treatment
system is needed to remove colloidal and soluble organic matter present in wastewater. Biological process is employed in this stage. The activated sludge process (an
aeration basin with return sludge activity) or trickling filter (a basin with fixed-filter
media filter) and secondary settling tank take place in this stage. During the process, the aerobic microorganism needs oxygen to absorb the organic matter from
wastewater. Other biological treatments provided for secondary treatment system to
cater specific needs are waste stabilization ponds (also known as oxidation ponds),
oxidation lagoons (aerated lagoons), oxidation ditches (extended aeration system),
Rotating Biological Contractor (RBC), Up-flow Anaerobic Filter (UAF) and Up-flow
Anaerobic Sludge Blanket (UASB) (Karia and Christian 2006).
The tertiary or advanced treatment system is needed if the effluent quality of secondary treatment system is unsuitable for final disposal requirement into the rivers or
lakes. The tertiary treatment usually focused on the removal of microorganisms, nutrients, elements and gases. The different techniques can be used for tertiary treatment
as in Table 4.2.
N. M. Jais et al.
meet the relevant environmental standards before final disposal into the rivers or lakes
(Karia and Christian 2006; Jais et al. 2016). On the other hand, the system should
be designed and constructed according to the engineering standard, for example the
concrete strength and suitable maintenance (Karia and Christian 2006).
4.4 Fresh Wastewater Treatment System
The wastewater treatment system is designed under several stages which are preliminary treatment system, primary treatment system, secondary treatment system and
tertiary or advanced treatment system. Preliminary treatment system is a method to
remove large inorganic particulate contents of wastewater or floating materials that
disturb the operation in primary and secondary treatment of wastewater. The preliminary treatment system includes bar screen for screening large floating materials
while grit chamber for heavy suspended solids. Some of the preliminary treatment
systems have skimming tank to trap oil and grease which is suitable for fresh market
wastewater. The primary treatment system aims for the separation of solids through
sedimentation or settling process in sedimentation tank. The wastewaters are left
in the tank for several hours to allow the particles to settle at the bottom of the
tank. The settleable suspended solids which are called as sludge are then removed or
drawn from the tank. This sludge may reduce 60–70 % of fine settleable suspended
solids which include about 30–32 % of organic suspended solids (Karia and Christian
2006).
After primary treatment, the biological treatment known as a secondary treatment
system is needed to remove colloidal and soluble organic matter present in wastewater. Biological process is employed in this stage. The activated sludge process (an
aeration basin with return sludge activity) or trickling filter (a basin with fixed-filter
media filter) and secondary settling tank take place in this stage. During the process, the aerobic microorganism needs oxygen to absorb the organic matter from
wastewater. Other biological treatments provided for secondary treatment system to
cater specific needs are waste stabilization ponds (also known as oxidation ponds),
oxidation lagoons (aerated lagoons), oxidation ditches (extended aeration system),
Rotating Biological Contractor (RBC), Up-flow Anaerobic Filter (UAF) and Up-flow
Anaerobic Sludge Blanket (UASB) (Karia and Christian 2006).
The tertiary or advanced treatment system is needed if the effluent quality of secondary treatment system is unsuitable for final disposal requirement into the rivers or
lakes. The tertiary treatment usually focused on the removal of microorganisms, nutrients, elements and gases. The different techniques can be used for tertiary treatment
as in Table 4.2.