In an industrial Nairobi neighbourhood, impoverished slum-dwellers scour piles of garbage to collect damaged and discarded gadgets, part of an initiative to recycle old electronics and transform trash into treasure. Wearing T-shirts and flip flops and earning as little as 500 Kenyan shillings ($4) a day, the unlikely warriors are at the frontlines of a battle against a rapidly-growing environmental menace. Obsolete, broken and unwanted, these discarded items reflect a global scourge, with the electronics industry now generating trash at a faster pace than any other sector, including textiles a…