Drip.Drop

Chitosan as the future of water filtration systems

The widespread problem of water pollution is jeopardizing our health. Unsafe water kills more people each year than war and all other forms of violence combined. Meanwhile, our drinkable water sources are finite: Less than 1 percent of the earth’s freshwater is actually accessible to us. Without action, the challenges will only increase by 2050, when global demand for freshwater is expected to be one-third greater than it is now.

Drip.Drop is positioned in the interstice here as the future for localising the water filtration systems in our community, bringing water to forefront of pollution discussions. The idea here is to involve the social aspect around water that has been existing since long but does not find an appropriate place in the current urban ecosystems. Bio materials hence become a great reagents to inform the filtration systems.

Waste Water Treatment // The usual cycle

Urban Water Cycles // Sanky Diagram (Existing)

Constituents of Waste Water // Grey Water

Textile Water Cycle // Sanky Diagram (Existing)

Chitosan // Bio material of the future

Availability:

Every year, some 6 million to 8 million tonnes of waste crab, shrimp and lobster shells are produced globally, about 1.5 million tonnes in southeast Asia alone. It is found in exoskeletons of crustaceans, the cuticles of insects, and the cells walls of fungi.

Fabrication:

Produced from Alkaline deacetylation (40–50% NaOH) of chitin where this N-deacetylation is almost never complete. The chitosan is considered as a partially N-deacetylated derivative of chitin.

Cost:

Dried Crustacean Shells, a byproduct of seafood industry are available at 100-200$ a tonne.

Key Advantages:

Biodegradable
Bio-compatible
Film-formability
Bioadhesivity
Hydrophilicity
Adsorption properties
Low cost of raw material

Chitosan // Flocculation and Coagulation

Experiment 1: Dye Coagulation

Run time: 30 minutes

0.1% Chitosan Solution
Prepared by mixing 1g Chitosan in 50ml 1% Acetic Acid Solution and 950ml Distilled water

Beaker
500ml Popular Soft Drink
ph = 3
(contains Tartarazine Dye)

0.5ml/1.0ml/1.5ml/2.5ml
Chitosan Solution

Stirring for 2 minutes

Observations:

Experiment 2: Sand Flocculation

Run time: 2 minutes

0.1% Chitosan Solution
Prepared by mixing 1g Chitosan in 50ml 1% Acetic Acid Solution and 950ml Distilled water

Beaker A
200ml water
25g Sand

Beaker B
200ml water
25g Sand
10ml 0.1% Chitosan Solution

Observations:

Experiment 3: Chitosan Sand Composite

Run time: 30 minutes

20mm Chitosan Powder, 90% Deacytelated

50cms Long Acrylic Tube
250mm Sand
Polyethylene mesh
3D Printed Nosel

Details
200ml of model dye water was poured into the tube. It took approximately 5 minutes to be filtered. The water came out nearly transparent but retained a slight blue tint. The process was repeated to attain the maximum filtration capacity of the filter.

Observations:

Experiment 4: Dye Water Filtration – Coffee Filter

Setup

Observations

Chitosan Membrane and Microscopic Observations

Design Proposal // Centralized to Decentralized Water Filtration Systems

Urban Water Cycle // Volumes

Water Filtration Requirements:

The average person in Spain uses 132 L of water per day, similarly, in India, the average water consumption per person is 135 L.
Average Barcelona Block is inhabited by 700-750 people.
Every block requires an average of 92,400 L of water per day.
Of those 92,400 L, 55,440 L is grey water.
Chitosan is optimal as a coagulant at approximately 30-50mg / L.
Average Barcelona block would require 2.21 Kg of Chitosan per day.

Urban Water Cycle // De-centralization Proposal

References // Precedents through History

Water Collection and Distribution Tanks
Social Aspects related to water : congregation and celebration

Understanding the Biological Processes // Filtration in human body

Filtration in Marine Animals // Filter Feeding Plankton’s

Sieving:

Water that flows into the filter passes straight through the holes in the end of the filter, similar to pasta strainer. Only suspended food particles that are too large to fit through the holes are captured.

Cross-Flow Filtration:

Water is re-directed sharply out of the holes on the side of the filter, while both large and small particles are shunted towards the collection area.

Vortex Filtration:

Ridges or plates located near holes on the side of the filter cause the water to form small vortices as it exits. Like tiny tornadoes, these vortices whip particles into the center of the filter.

Interception:

Food particles get stuck on sticky surfaces that they touch within the filter.