Doulton Ceramic Filter
In December, (2010) I made a simple gravity fed ceramic water filter
tool using two 5-gallon paint buckets, 6 inches of 1/2-inch diameter vinyl
tubing and one Doulton 7" Super Sterasyl ceramic filter. The filter tool is
shown in Figure 1. The total cost of this filter tool was about $43 which
includes $35 for the Super Sterasyl. This cost is higher than I would like,
since I try to develop my tools for poor people. However, the Super
Sterasyl is able to eliminate all sediments and 99.99% of all waterborne
bacteria, microbial cysts, and 100% of guinea worms. Plus, with its
carbon element it removes many chemicals and improves the taste of the
water. About the only thing this filter can't handle are virus like hepatitis A
that are too small for the ceramic pores to block. However, where virus
are a concern - SODIS, boiling or chlorine can be used for final treatment.
The flow rate is about 1-liter per hour, so plan on setting the filter to run
all night. Once I settled on the design, I was able to assemble this tool in
about 5-minutes. So far, this tool has produced the cleanest, freshest tasting
and safest water of all the filter treatments I have tried. To treat highly
turbid water, I have built a pre-filter module that will reduce maintenance
and extend the life of the ceramic filter. I plan to test other ceramic filters in
this gravity fed configuration and try to reduce the cost.
Finally, among the many advantages of ceramic filters include a high degree
of effectiveness in a small, lightweight, low maintenance package that can
to stored indefinitely and quickly deployed during times of need. Given
these advantages, the higher cost may be acceptable. Combined with
SODIS or chlorine, (for viral disinfection) this would be my top choice.
The main disadvantage is that in 6-month to a year, the ceramic filter needs
to be replaced at a cost of $35.
Making a Ceramic Gravity Filter
Doulton 7" Super Sterasyl Ceramic Filter W9121200 (long mount). The
filter unit inlcudes a sealing washer and 1/4-inch wing nut. Lowest price I
found was at FiltersFast.
6-inches of 1/2-inch diameter vinyl tubing.
Two 5-gallon (number 2) white plastic paint buckets.
Two 5-gallon bucket lids.
Drill and 1/4-inch drill bit.
Assemble the Top Filter Bucket
Place the ceramic filter lengthwise at the base of a 5-gallon bucket.
Mark place where the threaded outlet meets the bucket wall. Remove
the filter and drill a 1/4-inch hole through the bucket where you marked
the outlet. Insert the sealing washer through the threaded outlet. Push the
filter outlet through the 1/4-inch hole you just drilled. Fasten the wing nut,
securely - but DO NOT OVERTIGHTEN.
Assemble the Bottom Storage Bucket
Drill a 1/4-inch hole near the top of the bucket for the vinyl tubing inlet.
Add a facet to the bottom of the bucket. Cover the bucket with a lid and
place the filter bucket on top. Attach the vinyl tubing.
Figure 1. 5-Gallon Ceramic Gravity Filter using Doulton 7" Super Sterasyl