January 12, 2011
Health Sciences Campus, Kochi
Amrita’s Health Sciences campus has adopted an integrated waste management system based on the zero waste concept.
Waste is collected daily and brought to the recycling and disposal unit for processing. Some segregation is done at the points of collection itself. Red bags are used to collect blood-stained and infectious waste; yellow bags are used for body parts; green bags for food and other organic matter and black bags for all other general waste items.
The collected waste is further segregated into paper, plastic, glass and metal at the recycling unit. Special care is taken to disinfect syringes, before disposal. Infectious hospital waste is incinerated in accordance with currently prevailing norms in specially designed incinerators.
All organic waste including food waste, coconut shells, banana stems and dry leaves are taken to the composting unit. Since organic waste amounts to approximately 60% of the total waste, a special composting unit was built to allow for general composting as well as vermicomposting.
Composting results in rich, organic matter that can be used as manure to replenish soil fertility. Using compost helps make plants healthy and resistant to diseases and insects. Composting is a part of nature’s way of regenerating biomass.
Biomass typically contains both carbon and nitrogen. The composting process is begun by mixing matter rich in both such as food waste, water plants, soiled paper, tea dust, cow dung and wood chips. An electric shredder pulverizes large items such as coconut shells. Garden netting is used to cover the freshly made piles of decomposing matter for two to three days to avoid flies.
Mesophilic aerobic bacteria naturally present in all organic matter begin the process. With a moisture level of about 45% and in the presence of oxygen, these aerobic bacteria quickly go to work. The pile heats up to 40 degree Celsius. At this point, the mesophilic bacteria die off and the thermophilic bacteria take over, heating the pile to nearly 55 degree Celsius.
At this point, decomposition is at its fastest. At this temperature, oxygen gets depleted and the pile must be turned over to re-oxygenate the matter. After turning, the pile again quickly re-heats. By turning regularly, every portion of the pile is exposed to these high temperatures that kill any pathogens present and produce a uniform product.
Proper management is required to achieve consistent results. Temperatures and moisture levels are monitored as the piles are regularly turned. After four to six weeks, the piles will no longer heat up and the process concludes. Drying and curing entails the final stage of the process before the compost is packaged for distribution.
Vermicomposting is the second method that is used. Since the beginning of time, earthworms have created rich organic top soil by feeding on partially decomposed organic waste matter. The water hyacinth that clogs the backwaters at the Health Sciences campus is a nuisance; this invasive weed is harvested, chopped, mixed with cow dung, and allowed to ferment for 30 days in open tanks. When earthworms are added, in another 30 to 40 days, the feedstock is converted to the richest organic manure known to man.
Nature never needed pesticides. Only when man switched to synthetic fertilizers, pests become a problem. Natural organic manure that is high in all nutrients can help reduce the unfavorable impact of pesticides on the environment. By making and using compost, man remains in harmony with Mother Nature.