Answer:
Hydraulic retention time, so far, this natural method depends on nature(sunlight) for it operating mechanism, and treatments procedures it consumes a longer time due to ration of the sewage to sludge.
This may take an average of 3-5days for effective treatments.
Besides, this natural method comes with extra cost because of large quantity of sludge when ASP is used for treatment which needed to be disposed afterwards. This requires extra cost for the disposal.
Lastly, the rector thanks for the ASP, is usually large, requiring large portion of land. Thus the required size of land may no be available for the process to take place,
Explanation:
