“516. The council may, by resolution, whenever it sees fit, instruct the treasurer or any other officer to add to the amount of any taxes to be levied a sum of not more than ten per cent, to cover losses, costs and bad debts.
“518a. The costs of demolition, repairs, alteration and construction assumed by the corporation in exercising the powers contemplated in paragraphs 1b, 4a and 27 of section 426 shall constitute a claim to be levied and recovered as a special tax.
“536. The council may pass such by-laws as may be necessary to enforce the collection of any special tax imposed pursuant to this act.”