Wastewater TreatmentBy: Zach Montgomery, Benjamin Rawls, and Alex

Ryan

Introduction● “Although there are historical references from ancient times, the problem of

pollution of water has reached peak levels in recent times. It seriously jeopardizes the future of humanity not only due to the large industrial growth, also because of the demographic trends.” (Alrcon 1).

● Huge amounts of wastewater is created by humans each year● Untreated water leads to major contaminations in local water systems● Wastewater treatment aims to remove major contaminants from the water,

making it safer for human use and consumption ● Very important for water conservation and human life

Overall Process

Coagulation and Flocculation

Coagulation

● Wastewater contains many small particles which settle slowly, and can clog filters ● Don’t naturally clump due to negative charge● Coagulants added to neutralize negative charge

○ Common coagulants include iron and aluminum salts, some organic polymers● Rapid and thorough mixing occurs ● Microflocs form

○ Still to small to settle or filter easily

Flocculation● Gentle mixing to encourage

formation of larger and larger flocs

○ Rapid mixing would shear forming flocs

● Flocculants can be added to aid in floc formation.

○ Example include activated silicon, activated carbon, or talcum

● Once large flocs are formed the can easily settle out in a clarifier or be filtered.

Pros and Cons

Advantages

● Simple operation● Low cost ● Reliable

Disadvantages

● Requires constant stream of materials

● Initial setup can be difficult

Clarification● Second process

○ Input from flocculation output● Two output streams

○ S-117 has had three major contaminants sorted■ Flocculants■ Heavy Metals■ Suspended Solids

○ S-118 is a sludge mixer■ Sent to the Plate and Frame Filter

● Input Stream Concentrations○ Dissolved Salts: 0.519 g/L○ Flocculants: 0.098 g/L○ Heavy Metals: 0.007 g/L○ Suspended Solids: 1.46 g/L○ Water: 997.9 g/L

● S-117 Concentrations○ Dissolved Salts: 0.52 g/L○ Flocculants: 0.0012○ Heavy Metals: 0.000079○ Suspended Solid: 0.017○ Water: 999.5 g/L

● S-118 Concentrations○ Dissolved Salts: 0.515 g/L○ Flocculants: 0.62 g/L○ Heavy Metals: 0.042 g/L○ Suspended Solids: 9.33 g/L○ Water: 989.5 g/L

Clarification Economics

● Requires Heating, Cooling, Power, and Labor● Rates

○ Heating: 0.28 $/MT of Steam○ Cooling: 0.025 $/MT of Water○ Power: 0.10 $/kW-hr

● Starting Cost○ Clarifier= $20,606○ Installation= $4121.2○ Maintenance= $3090.9

Plate and Frame Filtration

Plate and Frame Filtration- Unit also referred to as filter press- Fed by slurry pump- Filter plates used to extract water from slurry- Extracted water continued into system, leftover cake removed

http://www.micronicsinc.com/wp-content/uploads/2015/12/Filter-Press-with-Cake-CartL.jpg

How it Workshttps://www.youtube.com/watch?v=M4wBd1_CvNw

How it Works

https://ertelalsop.com/how-does-a-filter-press-work/

Surface Filtration

Depth Filtration

https://ertelalsop.com/how-does-a-filter-press-work/http://www.suitafiltech.com/filterbag.files/filter%20press%20drawing.jpg

Sustainability- Plates must be replaced- Most energy intensive part of whole process

- Pump slurry- Air compression- Water removal

- Waste product can be used to help process until removed- Removed waste can be toxic

- Can be incinerated which uses additional energy- If used in land reclamation, should be put where no vegetation is possible

- Water sent to next phase must be treated to remove contaminants

Economics

Life Cycle Assignment ● Global warming effects come almost entirely from electricity use in the system ● Some carcinogens are still added back into the environment but much more

are removed

ReferencesAlarcon, Jessica Sarai Garcia, Antonio Rodriguez Martinez, and Israel Herrera Orozco. "Life Cycle Assessment to Municipal Wastewater Treatment Plant." Life Cycle Assessment to Municipal Wastewater Treatment Plant (n.d.): 1-6. Aidic.it. Universidad Autonoma Del Estado De Morelos. Web. 18 Apr. 2016.

Mazille, Félicien, and Dorothee Spuhler. "Coagulation-Flocculation." Sustainable Sanitation and Water Management Toolbox. Sustainable Waistwater Management Tool Box, n.d. Web. 18 Apr. 2016.