The fancy way

Wright Environmental http://www.wrightenvironmental.com/index_nonflash.html 600lbs to 30 tons/day $80,000 in 1998 according to http://compost.css.cornell.edu/NYCComposting.pdf

 

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The basic way

Source: http://apps.edf.org/article.cfm?contentID=2030
Dated: 2000-06-01
Updated: 2006-12-28  

 

How to Build a Compost Bin

To make compost you'll need a compost bin. You can purchase one ready-made, or make your own.

Commercially produced compost bins are readily available. They are often enclosed so that flies can't get in and smells can't get out. This may be a consideration if your garden is small. The bins have an open bottom which needs to be in direct contact with the soil to assist with drainage and enable worms and other organisms to enter and help in the composting process. Compost is easier to turn in larger bins.

Cover each 4 inch (10 cm) layer of waste in these bins with a shovel full of soil. A sprinkle of lime or dolomite over each layer helps to speed up the process.

Old garbage bins and boxes can be adapted to perform a similar function. For a class project with many students involved, building a compost bin may be preferable.

 

The compost itself can be made in a number of ways. The simple method, which produces usable compost in about 3 to 6 months, is to mix waste with a little soil and turning the compost with a garden fork every couple of weeks.

If you want to achieve faster results, layer your compost with alternate layers of waste and soil. Layers of waste should be no more than 4 to 6 inches (15 cm) deep with the coarsest material on the bottom. Alternate layers between green leafy material, dry leaves and twigs. Grass clippings and prunings should be placed in layers not more than 2 to 4 inches (5 cm to 10 cm) thick.

Each layer of waste should be moistened and then covered with a loose layer of soil. Adding some manure or blood and bone, a handful of lime dolomite or a commercial compost starter should increase the speed of the process. Be careful to avoid compacting the layers. Air needs to be able to circulate freely for composting to take place.

Repeat this layering until the compost heap has reached a height of about 5 feet (1.5 m). Ensure the compost doesn't become soggy or dry out and turn it every 5 days. This method produced rich compost in about 6 weeks. Not turning your compost regularly, simply means that it will be longer before it is usable.

 

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How to Build a Compost Bin

(Open Roads of New York, Inc. copyright 1995. This material may be used by any non-profit organization. Please acknowledge Open Roads.)

The following plans to build an aerated "hot" compost container were developed in numerous school workshops by Open Road, Inc..

 

Tools needed:

• Screwgun
• Square
• 2 1/2" Hole saw
• l/2" Drill bit
• l/8" Drill bit (for pre-drilling)

 

Materials and Measurements:

You should use a Square to mark-off your cuts. Be careful to cut straight and true. Do not rush this step or your container will not be square.

 

• 22 - 2"x 10" boards at 42" long for the Top, Bottom, and Sides.
• 4 - 2"x 10" boards at 38 1/4" long for the removable Front slats.
• 4 - 2"x 4" boards at 36 l/2" long for the Front and Rear Interior Braces.
• 1 - 2"x 4" board at 42" for the Horizontal Front Support Brace.
• 2 - 2"x 4" boards at 34 1/2" for the Vertical Front Support Braces.

 

Construction Tips:

All boards are fastened with 2 1/2" Phillips head screws. Use all purpose or galvanized screws for this job. Do not use sheetrock screws. You will need a power Screwgun to fasten these screws. If you have access to an electrical source nearby, a 3/8" standard drill with a screwdriver attachment will work well. A cordless Screwgun is a very handy tool for this job if you don't have any power source.

If you are using standard 2" x 10" wood lumber, "pre-drilling" your screw holes with a l/8" drill bit is highly recommended so you don't strip the screw heads. However, if you are using Recycled Plastic Lumber, no pre-drilling is necessary. Remember, 2" x 10" lumber is actually l l/2" x 9 l/4".

If you have no access to a Screwgun, you can try nailing with 2 l/2" nails (#8d galvanized). However, bins built using this technique will not be as strong or last as long.

You should try to have at least 3 people for this job. The more people you have the easier it is to support the boards during construction. This is especially important to make the box square, and when it is necessary to move the box around (it will get very heavy when completed) you may also want to divide into groups to handle the different tasks.

 

Important Note:

If you are using plastic lumber the shavings from sawing the boards are toxic and contain fiberglass. Make sure you wear gloves and a dust mask! Carefully collect the shavings and dispose of them. Use a drop-cloth under your cutting area to make clean-up easy.

 

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Step 1 Vertical Sides (You will need to make 2 of these)

Lay 4 - 42" boards on a flat surface. (Use two extra boards underneath if your working surface is irregular). Be careful to line-up these boards so the ends are flush and square.

 

Place the Rear Interior Brace (2"x 4"x 36 l/2") along one end of the 4 boards. Make sure this board is flush and square. You can use another board to assist in this. Make sure there are no gaps in your 2" x 10" 's. Fasten with 2 1/2" screws. Use 2-3 screws per board.

 

Place the Front Interior Brace (2" x 4" x 36 l/2") along the other end of the 4 boards. Recess this board 1 3/4". Make sure there are no gaps in your 2" x l0" 's. Fasten with 2 l/2" screws. Use 2-3 screws per board.

 

Repeat Step 1 for Side #2

Step 2 Back Side

Lift Side #1 upright with the 2" x l0" 's running vertically so you can fasten from the top down. Have l -2 persons hold in place as perpendicular as possible to your working surface. If you have extra hands available lift Side #2 upright as well. Remember you will be working from the Rear of the container now so the two sides with the "Rear Interior Braces" should be facing you and on the inside of the container.

 

Place the 1st 2" x 10" x 42" board on top of the sides. It is very important that you line-up and square this board to the sides. The corners should be flush. Fasten the first Screw on the lower right corner. Then fasten the top part of the board after making sure you are square. This technique allows you to adjust your square before adding more screws. Repeat this process on the left side. The Container should stand up on its own now. Now add the remaining 3 boards to complete the Rear Side. Again, make sure the Container is square and flush. You can then fasten an additional 2 screws on each end of each board for strength.

 

Step 3 Bottom

Flip the Container over on its Top (Imagine that the Top is now facing down ) Lay-out 5 2"x 10"x 42" boards on the side-rails running the same direction as the Rear Side. These boards will only fit flush one way! Square-up and flush starting from the Rear of the container and proceed to fasten boards with 2 screws at each end. Be careful to line up these screws so you don't miss the board underneath! Again, pay special attention that there are no gaps as you fasten all four bottom boards. You may need to stretch-out the front end for a flush fit. The last board will overlap so don't be alarmed.

 

Step 4 Front

Flip the container right-side-up with the Front Side facing you. Place the Front Support Brace horizontally at the top of the front face. Fasten one end first with two screws. You may need to stretch the two sides so the Front Support Brace will fit flush at each end. Fasten the other end with two screws.

Attach the external Vertical Front Support Braces. Make sure to let the overhang go to the center of the Container. This creates the groove for the Front Slats.

 

Step 5 Removable Front Slats

You will need to drill three 2 1/2" holes in 2 - 2" x 10" x 38" boards. You must use a power drill for this; it can be done "off-site" if necessary. Use a sharp hole saw bit and take your time. Make your first hole exactly in the center of the board (both horizontally and vertically). You may need to drill halfway through one side and then drill from the other side to complete the hole.

 

Measure 8" from each end and mark in the center of the board. Proceed to drill out these remaining two holes.

 

Repeat steps for second board.

Slide 1st board with holes down the groove inside the front. Then slide a board without holes; continue to alternate boards until closed. You are now ready to LOAD!

Step 6 Top

Simply lay 4 - 2" x 10"x 42" across the Top. Do not fasten for easy removal and temperature readings.

Step 7 Aeration

Cut 6 - 48" lengths of 2" PVC Pipe.

Drill 1/2" holes every 2 1/2" for internal aeration. Leave the last 8" of each Pipe without holes.

You may want to attach an internal brace inside of the rear wall for the upper layer of Pipes so they remain level.

Note: Carefully clean-up plastic shavings.

Step 8 Loading Container

Place a 2" layer of hay or woodchips on the floor. This will help absorb any extra moisture or food waste seepage.

Insert lower the layer of 2" pipes into the container.

Load Compostables. (A 50/50 mixture of carbon and nitrogen materials which may include: food waste, manure, woodchip, lawn clippings, leaves, etc.). You will also need to add some inert organic material such as finished compost or soil as a "starter". Mix materials well and fill up to the level of the second layer of pipes. Water evenly so mix is moist to slightly wet.

Insert second layer of Pipes into the Container. Rest on the optional rear brace so the pipes remain level and don't get shifted during loading and natural settling.

Continue loading mixture up to the last 8"-12" from the top.

Load a 4"-8" layer of finished Compost or soil for the "Bio-filter". This will help minimize the odor as well as convert the ammonia gases into usable nitrogen. Check the temperature daily. You should reach approximately 90 degrees within 3 days and 120 degrees within approximately 5 days if your mix is good. If not, remix and check moisture levels. A successful batch should reach 120-145 degrees for 2-3 weeks and then drop-off slowly over 2 weeks. If the temperature climbs over 150 degrees, adjust the amount of air by plugging tubes. The temperature may "crash" quickly if the bacteria within the desired heat range heat up too much. Unload finished COMPOST into a shallow curing bin or pile.

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Equipment Sources

Nearly all the equipment necessary can be found in a good hardware store. The only specialized piece of equipment for composting that cannot be purchased there in the requisite size is the Long-Stem Thermometer used to measure temperatures in the compost bin. This thermometer probe can be obtained from:

Reotemp Instrument Corp.
10656 Roselle Street
San Diego, CA  92121 
(800) 648-7737

If you wish to obtain further monitoring or testing equipment such as oxygen meters and probes, maturity testing kits and testing information contact:

Woods End Research Laboratory, Inc.
P.O. Box 297
20 Old Rome Road
Mt. Vernon, Maine  04352
(800) 451-0337