SWT

*Example of layout: PLEASE NOTE that each plant is customized and the system components showed in this photo can vary according to projects requirements.

The Newster SWT process for the treatment of infectious wastewater in hospitals

STAGE 1: Pre-treatment tank 

The first stage of the treatment takes place in a tank equipped with a digital level sensor system for the control of the inner plant flow rate. The pre-treatment tank is very important in order to reach the correct homogenization of the sewage water and the correct buffer volume.

STAGE 2: solid-liquid separation

During this stage the liquid passes through the mechanical filters, where the solids are compacted. The liquid is filtered through a stainless steel with 5 mm diameter holes with a constant curvature, fixed to special supports. The pierced sheet is continually cleaned by four nylon brushes installed on rotating arms. Solids are pressed against the pierced surface by four rotating rubber rolls installed on special elements ensuring a regular pressure. The sludge reaches a sufficient dehydration degree and it is unloaded by the two adjustable nylon brushes. The water is collected in the separator’s lower part of the tank and from there transferred to the disinfection tank by open impeller pumps. Where possible, the transfer is made by drop. 

The separated solids are collected into a dedicated container that can then be treated through a Newster NW sterilizer.

STAGE 3: disinfection of infected liquids and final drainage to sewer

The disinfection tank is designed to achieve the right mix between wastewater and disinfectants. The PLC controls the process in order to add the necessary dose of chemicals based on the reading of specific chemical and physical parameters. The peracetic acid, mainly used as disinfectant, creates an acid environment in the disinfection tank. A basic product, usually sodium hydroxide, is used to maintain a pH value of 7. The disinfection tank is designed to guarantee a 30-minutes contact between the disinfectant agents and the infectious wastewater (if peracetic acid is used, 20 minutes contact is sufficient to guarantee the disinfection). When the time is up, the wastewater is ready to be discharged.