VoxSton – A New Water Clarification System

*Juhani Pylkkanen*

#### **Abstract**

A new water clarification system for industrial and communal wastewater is presented here. The system consists of two centrifugal separators, a screw separator and two vortex flow flotation units. It can separate the solids like fibers out of the sludge and press them to dry matter content of up to 30 percent and clean the sludge water for recycling and discharge to nature. The clarification system can, in most cases, treat process and communal sludge continuously or daily basis directly from outlets of the wastewater to be treated to finish without equalization and precipitation. The objective is to recycle the process and wastewater, and to collect different ingredients for reuse as much as possible, and to prevent microbe growth. The new system saves in energy and space as well as in operational costs by roughly 50 percent compared to present advanced systems. The capital costs are estimated to be lower too. The new treatment or part of it has been applied for purification of various water matrices from city and industrial wastewaters to natural lake waters.

**Keywords:** water treatment, water purification, flotation, particle removal, recycling, separation, clarification, integrated clarification, pharmaceutic residues removal, radon removal

#### **1. Introduction**

A new industrial process and communal wastewater clarification system VoxSton developed by SansOx Ltd. and Rannan Teollisuuskone Oy in Finland is presented in this chapter. The system consists of two centrifugal separators, a screw separator and two vortex flow flotation units. It can separate the solids like fibers out of the sludge and press them to dry matter content of 30 percent, and clean the sludge water for recycling and discharge to nature.

The first test runs have been conducted process phase by phase with real pulp and paper process sludge successfully. The treatment or part of it has been applied for purification of various water matrices from city and industrial wastewaters to refreshing of natural lake waters. The special feature of the system is that the industrial and communal sludge can be treated in most cases continuously or daily basis directly from the liquid outlet to finish without equalization and precipitation in terms of hours instead of days and weeks. Separation and recycling potential is presented in **Figure 1**. The water treatment technology discussed here is able to fulfill the most separation demands presented in the figure. Removal of the separated ingredients

#### **Figure 1.** *Industrial recycling economy.*

for recycling might need dedicated filtering. The most challenging separation and removal cases have been dealt with radon gas, pharmaceutic residues and disinfection of a hospital wastewater.

The new system saves in energy and chemicals, and in space as well as in operational costs roughly 50 percent compared to present advanced systems. The treatment process is integrated and fast. Use of chemicals has been reduced significantly due to molecular activation and efficient mixing in hermetic tube condition. For example CO2 consumption was reduced to 1/5 by OxTube in a Ca removal case. The capital costs are estimated to be lower too. The main benefits of the new treatment system are presented in **Table 1**.
