Workers at five recycling sites in Sheffield struck last weekend over job cuts.
Bosses drafted in casual staff over the two days in an effort to keep some of the sites open.
The strikers, in the GMB union, are among the lowest paid across the council.
They are paid the minimum wage of £6.08 an hour—nearly half the amount that council bin workers receive.
They rely on bonus payments to top up their pay. Yet workers say the targets to receive the bonus have been raised to a level that is impossible to achieve.
Sova Recycling has been subcontracted to run the recycling centres by council private waste partner Veolia.
Workers say they could strike on weekends throughout September.