Such was the symbiotic relationship between city and surrounding countryside. In Chinese Architecture and Town Planning, Andrew Boyd describes how private operators would collect the excrement from residences at night and haul it in carts out to the outlying farms.
《中國古建築與都市》書中指出，中國城市裡的汙物處理，通常是由私人經營的手推車負責，他們在晚間逐戶從廁所收糞便，然後運到城外周圍的農場，作為堆肥用的肥料。