Weight of the average raw hide (or ‘green hide’) is 30kg
Nothing To Hide: Hide and Skin Production Around The World

1000kg / 30kg of hide = ~33 hides per tonne

“For each tonne of rawhide, the industry obtains 200-250 kg of leather, tanned using chromium… 500 kg of chemical substances and 9.3-42 GJ of energy. Thus, for each tonne of skins processed, we obtain 60-250 tonnes of waste water to be purified (with 20-30 kg of chromium and 50 kg of sulphide, among others), 1800-3650 kg of solid residues, 2500 kg of sludge, 4-50 kg of solvents in emissions of air.”

Moving waste from one tonne to per hide:

1800-3650 kg of solid residues  - (3650+1800) / 2 = 2725kg of residue / 33 hides = 82.56kg of solid residues for one hide

2500kg of sludge / 33 hides = 75.76kg of sludge for one hide
Chromium, lead and cadmium all exist in high levels in tannery sludge
Characterisation and Composting of Tannery Sludge

An average cow hide is 55sq ft (5.10967sq m) 
Moore & Giles Leather, Garrett Leather

An average pair of shoes requires 3-5 sq ft of leather, 5-8 sq ft for boots
Willy Moc Hand Crafted Shoes For Anyone, Russel Moccasin Co 

Bag leather requirements from e-mail correspondence with Sans Beast (0.914m2), jacket leather requirements based on e-mail correspondence with Moore & Giles Inc (10-15sq ft, averaged and converted to m2)

(Say that 1 pair of shoes = ~4sq ft and 1 pair of boots = 6.5sq ft)

(55sq ft / 4sq ft) = 13.75 pairs of shoes from one hide/animal 

(55sq ft / 6.5sq ft) = 8.46 pairs of boots from one hide/animal

75.76kg of sludge / 13.75 shoes
A pair of shoes made from a ‘beef’ cow = 5.5kg of tannery sludge

75.76kg of sludge / 8.46 boots
A pair of boots made from a ‘beef’ cow = 8.95kg of tannery sludge

(55sq ft / 9.84 sq ft = 5.59 bags per cow hide
75.76kg sludge (per cow hide) / 5.59 = 13.55kg sludge per bag
A leather tote bag made from a ‘beef’ cow = 13.55kg of tannery sludge


(55sq ft / 12.5 sq ft = 4.4 jackets per cow hide
75.76kg sludge (per cow hide) / 5.59 = 17.22kg sludge per jacket
A leather jacket made from a ‘beef’ cow = 17.22kg of tannery sludge