System and method for the treatment of wastewater

A method of backwashing a sand filter in a wastewater treatment system, the method comprising:

• a) flowing wastewater through at least one sand filter in a first flow direction;
• b) backwashing the at least one sand filter to form backwashed water;
• and
• c) upon initiation of step b), automatically injecting chlorine into the at least one sand filter.

A system for backwashing a sand filter comprising:

• at least one sand filter configured to remove solids from an untreated wastewater;
• a container storing chlorine therein, the container being fluidly coupled to the at least one sand filter by a chlorine supply manifold;
• a flow control mechanism positioned on the chlorine supply manifold between the container and the at least one sand filter, the flow control mechanism alterable between a first position whereby chlorine cannot flow from the container to the at least one sand filter and a second position whereby chlorine flows from the container to the at least one sand filter, the flow control mechanism being biased into the first position;
• and
• a processor operably coupled to the flow control mechanism and configured to automatically actuate the flow control mechanism into the second position to flow the chlorine from the container into the at least one sand filter upon detecting that the at least one sand filter is being backwashed.