If any county treasurer or other person entrusted with the collection of assessments fails to make prompt payment of the assessment or any part thereof collected under this chapter to the treasurer of the sanitary district upon his presentation of a proper demand, he shall forfeit ten per cent on the amount of his delinquency. Such forfeiture shall at once become due and payable and both he and his sureties shall be liable therefor on his official bond. The county treasurer shall retain for his services one per cent of the amount he collects on delinquent assessments.