Wastewater treatment can be accomplished using ponds (aka, lagoons). Ponds are relatively easy to build, to manage, they accommodate large fluctuations in flow, and they can also provide treatment that approaches conventional systems (producing a highly purified effluent) at much lower cost. It is the cost (the economics) that drives many managers to decide on the pond option. The actual degree of treatment provided depends on the type and number of ponds used. Ponds can be used as the sole type of treatment or they can be used in conjunction with other forms of wastewater treatment; that is, other treatment unit processes followed by a pond or a pond followed by other treatment processes-- Provided by publisher.