PE PDH
PDH Online

Domestic Wastewater Treatment 17 HSW LU Hours


Quiz Questions

1.Preliminary treatment is defined as any physical or chemical process at the wastewater treatment plant that precedes primary treatment. Its function is mainly to protect subsequent treatment units and to minimize operation problems.
True
False
2. Primary treatment is defined as physical or , at times, chemical treatment for the removal of settleable and floatable materials.
True
False
3.Secondary treatment is defined as processes which sue biological and at times, chemical treatment to accomplish substantial removal of dissolved organics and colloidal materials.
True
False
4.Typical industrial discharges include wastewaters from the following:

  • Wastewater treatment
  • Maintenance facilities
  • Vehicle wash areas
  • Weapons cleaning buildings
  • Boiler blowdowns
  • Swimming pool backwash water
  • Water treatment plant backwash
  • Cooling tower blowdown
  • Fire fighting facility
  • Photographic laboratory
  • Medical or dental laboratories
True
False
5.Treatment systems handling less than 1.0 million gallons per day are generally considered small treatment systems.
True
False
6.Septic tanks perform settling and digestion functions and are effective in treating 1 to 300 population equivalents of waste, but will be used only for 1 to 25 population equivalents, except when septic tanks are the most economical for larger populations within the above range.
True
False
7.Septic tanks, biological package treatment plants, and stabilization pond are cost effective and require less operational and maintenance attention than other treatment options.
True
False
8.Improved solids separation in primary and secondary settling tanks or clarifiers results in concurrent reduction of biochemical oxygen demand levels in the tank effluent.
True
False
9.Chemicals may be added to the primary settling tank as a means of upgrading performance and relieving organic overloading in wastewater treatment plants; but it is not normal practice to add chemicals to secondary clarifiers since aerobic biological sludge flocculates and settles readily when normal growth conditions are maintained i.e., sludge retention times are optimized.
True
False
10.Shallow depth settling systems such as tube settlers have been used, to a limited extent, in primary and secondary clarifiers to improve performance as well as to increase throughout in existing tanks. These settlers capture settleable solids at higher than normal overflow rates. However, they do not improve the efficiency of primary clarifiers that are already achieving high degrees of suspended solids removal (40 to 60 percent)
True
False
11.Which one of the following techniques can be used for upgrading existing trickling filter plants.
Conversion of low-rate trickling filters to high-rate tickling filter.
Conversion from single-stage to a two-stage filtration system.
Conversion of single stage trickling filter to two-stage biological system
Upgrading an existing two-stage trickling filter.
All of the above
12.Advanced wastewater treatment encompasses several individual unit operations used separately or in combination with other processes, to achieve very high overall treatment efficiencies. These processes employ physical, chemical and biological treatment methods. The objective of advanced wastewater treatment is to improve the removal of suspended solids, organic matter, dissolved solids, and nutrients.
True
False
13.Preliminary treatment of waste water includes screening, grinding, grit removal, flotation, equilization, and flocculation.
True
False
14.The purpose of primary treatment is to remove solids which are not removed during preliminary treatment. Processes which can be used to provide primary treatment include the following:

– Primary sedimentation, also called clarification
– Microscreens
– Imhoff tanks

True
False
15.Trickling filter plants have been justified by their low initial cost, low operating and maintenance costs, and relative simplicity of operation. Although the effluent from trickling filter plants of earlier design was of poorer quality than that from activated sludge plants, the performance of trickling filters designed more recently is comparable to that from activated sludge plants.
True
False
16.In a conventional (plug-flow) activated sludge plant (fig 13-1), the primary treated wastewater and acclimated micro-organisms (activated sludge or biomass) are aerated in a basin or tank.
True
False
17.A wastewater stablizaion pond is a relatively shallow body of wastewater contained in an earthen basin which is designed to treat wastewater. They are used to treat a variety of wastewaters, from domestic wastewater to complex industrial waters, and they function under a wide range of weather conditions i.e. tropical to arctic.
True
False
18.Sludge, or residual solids, is the end product of wastewater treatment, whether biological or physical/chemical treatment. Primary sludge is from 3 to 6 percent solids. Treatment objectives are reduction of the sludge and volume, rendering it suitable for ultimate disposal. Secondary objectives are to utilize the generated gas if anaerobic digestion is selected as part of the sludge management strategy. In addition, an attempt should be made to sell/utilize the sludge as a soil conditioner rather than paying to dispose if it.
True
False
19.Disinfections is a process in which pathogenic organism are destroyed or inactivated. This process may be accomplished by physiochemical treatment or addition of chemical reagents.
True
False
20.In designing and constructing any wastewater treatment facility, a number of miscellaneous design details must be considered. They include water supply systems, lighting requirements, service buildings and equipment, landscaping, and proprietary process and equipment.
True
False