Page 16 RAIN January 1979 Connected with the pri\y a~nd pigpen excreta outlets 1 C!!~s~agas - ------------ --i---41-1-- ----- Gas vent pipe Applied ocrela tank Intake chamber I recently encountered an exciting and innovative project in the Midwest. Ted Landers of the New Life Farm, Inc., Drury, MO, has a grant from the Community Services Administration-(CSA) to build several of the People's Republic of China (PRC) style digesters on rural farms in the South and Midwest. Ted is working with the Midland Energy Institute (a Kansas City based CSA organization) and the University of Missouri at Rolla. . Ted and New Life,_Farms have for some time been in- Fig. 48. volved in digester work through the University of Missouri. They are currently conducting experiments with a 16,boo gallon digester to evaluate the use of hay and other croplike residues as a digester feedstock. The PRC Digester is quickly becoming a.t. jargon. It's "in" to be at le.ast talking about building a "Chinese digester." The truth is that these are little more than septic tanks; they produce about 1/10 the gas per volume that mixed sewage treatment digesters do. They are appropriate ,to the Chinese situation of cheap materials and labor. At $30-$35 per cu. ,meter for concrete in the U.S. , they may be far too expensive. The work that Ted Landers is doing will explore different materials for construction of these digesters. 'He will also,be doing a training program to aid local CSA organizations in developing the skills to assist low income people in the construction of these PRC type digesters after the initial protbtypes have been completed. ' Over·200,000 of these digesters were installed on farms in China. This was accomplished in a period of less than five years. The secret of this rapid development was a well-trained cadre o( te'chnicians who assisted local commm1es in the design. and construction of the units. • Professor William Jewell at Cornell has for.several years been working with anaerobic digestion (AD) for use on typi- ·cal farms in the U.S. In 1976, the Cornell group headed by Jewell published a most extensive report on the feasibility of farm applications of AD. This report is stil~ available through NTIS and is highly recommended for anyone who is serioµs about the implementation of this technology. This report to ERDA (Now Department of Energy- DOE) details the history of the European experiences with AD immediately after WWII. It gives the usual gross estimates of the energy potential from plant and animal resources in the U.S., but it goes beyond that to describe and estimate specific energy requirements for small dairies in t_he U.S. (40-109 head) and feedlots of 1,000 head. The report compares energy use with that which might be obtained from AD on the farm, with projected cost for different size farm operations. The report is available: Bio-Conversion of Agricultural Waste for Energy Conser'l.!ation and Pollution Control, 1976, William J. Jewell, $10.00 from: NTIS/Dept. of Commerce 5285 Port Royal Road Springfield, VA 22161 itit Jewell and the c'ornell group have subsequently set out to prove the technology. A report published this year (February, 1978) details the work which has been going on for the past three years in an attempt to look very carefully at different types of reactors. Connected opening Excrcta overno~ hole Fermentation lank door Enclosed three-stage biogas plant wi'th applied excreta tank. . Jewell has suggested that nothing has substantially changed in the AD technology since the '30s. The work at Cornell is an attempt to approach this problem in a very systematic manner: .looking both at simple, low-cost, unmixed reactors, as well as high-rate, fluidized bed filters. Details of this work are ~overed by the report, which' is also available from NTIS under the following title: Anaerobic Fermentation ofAgricultural Residue: Potential for Improvement and Implementation (HCP/T2981-07) Final Report-February 1978. Prepared for U.S. Department of Energy, William J. Jewell, $14.50, from above address. Currently the Cornell group is working with a full-scale, unmixed, plug-flow digester. It is loaded daily with manure from 6 5 dairy cows from the -Cornell barns. A second reactoFis a mixed, cylindrical tank (similar to sewage treatment type AD) which is also sized and loaded with manure from 65 dairy cows. The mixed tank is an experimental control as a comparison for the plug-flow unit. The plug-flow unit is an insulated, plastic lined trench in the ground with_a hypalon cover for gas storage. The unit has been in operation since late summer. Details of the results of these experiments are as yet unpul::>lished. A final note for this month is on the work being published· by the International Development Research Centre, which is a public corporation created by the Parliament of Canada in 1970. This is the group which published the report on the Chinese digesters (Rain, October 1978). The IDRC has been publishing some of the best recent reports on biogas activities in Asia and the Pacific. The most recent work which I have had a chance to review is: Biagas Technology in the Third World. This publication gives an update of the current reports from the East. "Biogas Systems in. Asia: A Survey by S. K. Subramanian," gives an overview of tqe spread of the technology. There is also an excellent sectfon on p,rojected crop and animal yielgs, a comparison of different AD reactors and their yields. • - IDRC publications are available in the U.S. from UNIPUB, a New York based bookstore. Both this publication and the previous publication on the Chinese digesters is available through UNIPUB:: • Biagas Technology in the Third World- A Multidisciplinary View, IDRC-103e, 1978, Andrew Barnett, Leo Pyle, S. K. Subramanian, $5.00 from: UNIPUB Box 433 Murray Hill Station New York, NY 10016·
RkJQdWJsaXNoZXIy NTc4NTAz