From the Guardian:
The ecological toilets installed at Daxing were the design of Sweden’s Stockholm Environment Institute — about five million people use the model worldwide. In China, they are manufactured in the south-coast city of Chaozhou and cost about 700 or 800 yuan (US$100-125). Unlike normal toilets, they separate urine and excrement. In short, you aim your urine at the urine bowl and it is piped to an underground storage tank. And when you sit down, an excrement receptacle automatically pops out. You pull a lever to sprinkle some sawdust over your waste, and then when you stand up it flips over and everything is dumped down an excrement pipe to a tank in the basement. The tank is emptied two or three times monthly.
No water is used for flushing in either case — the cistern is full of sawdust, which residents collect from an office on-site. The toilets are designed to save water, prevent odours, and turn excrement into fertiliser. Fans blow air out of the pipes to the roof, and this is meant to ensure that smells do not enter the apartments.
Yan’s family just couldn’t get used to it. The toilet smelled bad from day one, they said: there was a stench of ammonia throughout the house, sometimes enough to make their eyes water as soon as they stepped into the bathroom. “I could hardly eat at home, and felt miserable on my way back after work,” said Yan. So the family usually ended up eating at Yan’s sister’s house. And their relatives didn’t want to visit.
The excrement bowls, which need to rotate, started to break. Every single house had to have the bowls repaired, and in 60% of households they needed to be replaced frequently. In 2007, Yan’s toilet was changed for one with a retractable tray, but the smells didn’t improve.