Introduction: DIY Water Treatment Tower

This water treatment tower combines a few #DIYBMP devices for filtration or adsorption in a number of different water treatment applications:

- stormwater treatment

- pond filtration

- large aquarium filtration

- hydroponics & aquaponics

- aquaculture

- rainwater harvesting

- natural swimming pool


This Instructable details how to build a clarifier box and an active media box.

Depending on your application and contaminants of concern, each piece could stand alone or be included in the full treatment train detailed here.

I work professionally in the water treatment industry and maintain some water-centric hobbies. Knowing that I tinker in small-scale, inexpensive versions of industrial equipment, friends have asked how they might build their own systems for their hobbies or businesses - for rainwater harvesting, aquaponics, aquaculture, aquariums, and even industrial stormwater treatment. My Instructables about DIY aquatics equipment are meant to share some of the hacks, science, and builds more broadly with others.

Step 1: Make the Clarifier Box

This is a basic horizontal clarifier for pre-treatment in a number of different water treatment applications.


Target Contaminants - Total Suspended Solids

Estimated Flow - 75 gallons per minute

Action - Separates bulk solids that sink or float; approximately 4 minutes retention to settle bulk solids

Project Estimate - $30


Step 1: Gather Parts
(1) 275 gal IBC tote from local reclaim or Craigslist

(1) Banjo 2" bulkhead from Amazon.com

Parts from Home Depot

(1) 2" PVC adapter (MPT x slip)

(1) 2" PVC stub (6")

(1) 2" PVC Tee


Step 2: Prep Tote

Drill hole for the skim drain bulkhead approximately 6” from top of tank at the center of wall opposite from IBC drain valve.

Drill or cut hole on top of tank as appropriate to receive stormwater
from site downspout, diverter, or pump.


Step 3: Install Bulkhead Fittings

Install skim drain bulkhead.


Step 4: Install Internal Plumbing

Install skim drain PVC assembly.


Step 5: Install External Plumbing

Install fill plumbing as desired from source.

Install drain plumbing as desired to reach next treatment step or discharge location.

Depending on the layout and application, elevating the clarifier box will enable gravity flow. Four concrete blocks makes a safe and stable platform up to 3 layers tall.

Step 2: Build the Filter Box

This is a modified slow sand filter for filtration and active adsorption of heavy metals and nutrients.


Target Contaminants - Total Suspended Solids

Heavy Metals (Zn, Cu, Al, Fe)

Nutrients (COD, BOD, Ammonia)

Estimated Flow - 75 gallons per minute

Action - Actively adsorbs heavy metals and nutrients

Project Estimate - $900


Step 1: Gather Parts

(1) 275 gal IBC tote from local reclaim or Craigslist

(1) Banjo 2" bulkhead from Amazon.com

Parts from Home Depot

(2) 2" PVC adapter (MPT x slip)

(5) 2" PVC stub (3")

(3) 2" PVC Tee

(2) 2" PVC Elbow 90

(4) 2" PVC perforated underdrain (30") - pre-drill 1/4" holes or cut slits using saw

(4) 2" PVC Cap

(5) 4’ x 4’ section weed barrier fabric (separators between the media layers)


Step 2: Prep Tote

Drill hole for the underdrain bulkhead approximately 3” from bottom of tank at the center of wall opposite from IBC drain valve.

Cut hole on top of tank as appropriate to receive stormwater from site downspout, diverter, pump, or clarifier pretreatment stacked on top of filter box.


Step 3: Install Bulkhead Fittings

Install underdrain bulkhead.


Step 4: Install Internal Plumbing

Install underdrain manifold and underdrain perforated PVC pipes.


Step 5: Install External Plumbing

Install discharge plumbing as desired.

Install drain plumbing as desired to reach next treatment step or discharge location. Depending on the layout and application, elevating the filter box will enable gravity flow. Four concrete blocks makes a safe and stable platform up to 3 layers tall.


Step 6: Install Media Bed

Install media, separating each type with a section of weed barrier fabric.

(16 bags) Drain Rock for drainage support (8" layer)

(20 bags) Pea Gravel for solids separation down to 300 microns (2 x 5" layer)

(24 bags) Pool Filter Sand for solids separation to 30 microns (12" layer) - best pricing at your local pool supply

(24 bags) Active media - Zeolite for adsorption of metals & nutrients (25" layer) - may be locally available as "horse stall deodorizer" at farm or feed store

Step 3: Set Up the Tower

Step 1: Gather Parts

(1) 2" PVC adapter (MPT x slip)

(1) 2" PVC stub (3")

(1) 2" PVC Drop tube (34")

(2) 2" PVC Elbow 90

(1) 2" PVC stub (6")

(1) 2" PVC Tee


Step 2: Stack

Stack the Clarifier Box on top of Filter Box.


Step 3: Connect

Connect clarifier skim drain to PVC tower drain assembly.

If there is not a forklift available to lift and place the clarifier box (as pictured), two people could safely lift the clarifier.

Step 4: ...or Assemble a Hybrid Treatment Train

Note that for some applications, combining the large and small DIYBMPs may work well for isolating active media into a separate container for easier change-out or recharge. See the "Hybrid Treatment Train" examples attached to this step.

Check out the DIY Water Treatment Train for details on constructing the smaller scale DIYBMPs.