VPE 511: Environment and Environmental Hygiene (2+1)

TYPES OF MANURE AND SOLID WASTE

• The production of manure is on an average 40 kg per day per one adult unit ( one adult cattle or buffalo above 3 years of age). One calf blow one year or one adult sheep or goat or pig produces manure roughly equal to 1/3^rd of an adult unit.
• Aggregates of small globules are voided by sheep and goats, which are quite hard and can be swept of floors. For pig paddock, 0.5 m wide trench covered with slats or iron grills can be provided along the outer border where the animals will void the faeces which will drop through the grill to fall at the bottom of the trench, from where it can be collected periodically.

Manure pit

• Simple manure pit for villages can be constructed by digging out on an elevated land 4x3 sqm pit of 2 m depth with a roof constructed of locally available material. The objective is to desiccate the manure quickly to dung cake, and to prevent entry of rain water into the pit to overcome leaching of plant nutrients.
• Another way is to construct a brick walled pit with cement concrete bottom. There should be fall of base to one end from where a drain is to lead to the liquid manure chamber. This pit as usual would have roof at a height of permitting free circulation of air over the manure yet preventing leaching of valuable soluble plant nutrients. It also prevents anaerobic conditions causing deterioration of manure.
• The manure is well turned periodically to ensure uniform decomposition of fresh manure that is added to the pit daily. It is essential for destruction of eggs and larvae of parasites which are normally present in the dung of animals.

Biogas plant

• At village or farm level, the disposal of farmyard manure can be utilized for production biogas, fertilizer or compost. The Ministry of Non-Conventional Energy Resources, Govt. of India, is implementing biogas program, - gas being produced from cattle dung, other organic wastes and / or human excreta in a system popularly known as Gobar-gas plant through the process of digestion. The plant consist of
  • Mixing tank and inlet
  • Digester
  • Gas holder or storage dome
• The slurry from the biogas plant is a good quality manure free from weeds, sedds, foul smell and pathogens.

 Biogas plant

Liquid manure

• When the slurry from the biogas plant is used in liquid form as it comes out, it can be easily distributed in the field by linking the outlets with the main irrigation channel or through an appropriate handling system.

Composting

• Rectangular pits of 3x2x1.5 m are dug. A layer of straw, animal bedding, garbage and leaves is first put in the pit. Digested slurry is then allowed to flow into the pit. Alternate layers of refuse and slurry are laid until the pit is full. Bamboo poles having holes 10cm apart are placed in the compostable material for aeration. Finally the pit is plastered with mud layer. This will minimize the loss of nitrogen from the pit. After one pit is filled, the same process is repeated for filling another pits because compost from such pits is usable as manure only after 3 to 4 months. Composting process consist of compost heaps, semi-dried slurry and slurry filter bed.