It is difficult to so上放lve the problem o話動f sewage discharge caused by high under視師ground water le窗熱vel and narrow sp自雪ace. The sewage discharge point do書熱es not store sewage, does not need t紙現o be connected to electr飛子icity, the pipelin雜吧e is thin, the broken road surf文舞ace is less, the bur去是ied depth is shallow, and there is n水做o lifting pump 校購station.