NOVELTY - Apparatus for treating waste comprises closeable cell for processing waste to produce biogas, where the cell bears all or some of the weight of an associated building.    USE - For generating biogas for heating a greenhouse. For processing fish farm waste or chicken manure. Treatment of municipal solid waste or other wastes to produce biogas, preferably for heat and energy supply to an associated building such as a greenhouse. Treated waste is used as compost. Leachate is collected and dried to produce fertilizer.    ADVANTAGE - The biogas is a valuable energy source. Treated waste and leachate can be used as compost and fertilizer respectively. Waste volume is substantially reduced in a short time. Odor is reduced. The cost of the associated building is reduced by using the roof of the cells as foundation.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for the following:    (1) a closeable cell for producing biogas, with fixed floor, walls and roof;    (2) a waste treatment apparatus including cells for processing waste to produce biogas; access way is alongside each cell, process parameters may be monitored from the access way;    (3) treating waste in a closed cell to produce biogas; the processed waste is dried using heat generated from the biogas or from processing;    (4) an apparatus with parallel rows of cells, fluid distribution is in the space between the rows;    (5) treating waste including collecting leachate and returning it to the waste at a temperature to hasten the reaction;    (6) using multiple cells, including loading waste successively into cells, producing biogas and preparing cells, where each cell operates in cycle, with one additional cell being available;    (7) an apparatus including source for supplying liquid to submerge waste;    (8) an apparatus which produces biogas to generate energy for use in the associated building.    DESCRIPTION OF DRAWING(S) - The drawing shows a cross-section of one embodiment.    fermentation structure (90)    ground (91)    building (92)    cells (126,128 etc)    greenhouse section (158)    three-storey section with power generating plant (160,164)    conveyors (168,170)    extractor (172)    central section with plant for recovering non-biodegradable waste (162)