Compact Biological Waste Water Treatment Unit

Description

The compact waste water treatment unit is a containerised plant, ready for use, assembled and fully testes in our workshop.

The unit is designed to treat domestic water of 165 population equivalent (PE).

Outside dimensions: 6058 mm x 2438 mm x H 2895 mm (shipping container 20 ft)

Empty weight: < 4 tons

Power supply: 3 kW for the unit with the waste water pump

 

Waste water:

Domestic waste water comes from tourist resorts, remote villages, hotel infrastructure, for instance.

The number of 165 population equivalent (PE) represents a pollution load of 60 g BOD/day.PE, with a maximum flow of 25 m³/day, or 10 kg BOD/day.

Treated water:

Treated water has the following parameters:

Treated water may be reused for irrigation or recycled and reused, with or without further treatment.

Sludge:

Very compact and mineralised sludge can be directly valorised in agriculture.

Principles

The proposed system starts by pumping waste water with a grinder/comminutor (that avoids the common problems with screens), then a pre-treatment in a settling tank, an aerobic, biological treatment on fixed-bed, submerged and aerated biofilm, and finally a settling in a clarifier.

The process of the permanently submerged aerated fixed-bed combines the advantages of the trickling filter technology with those of the activated sludge process, while avoiding their well-known downsides.

The submerged fixed-bed technology is appropriate for individual sewage plants as well as for plants with a capacity of up to 10.000 population equivalents either for municipal or for industrial sewage. Both, a very effective biological degradation of organic carbon compounds as well as the denitrification are easily and economically achieved.

Operation

It is based on biofilm technology, using a mount made of synthetic material as a base for sessile (i.e. clinging to the surface) micro-organisms which are responsible for the actual sewage clarification. The oxygen supply is provided by blowing air from below into the fixed-bed. The blower is located in the technical room integrated in the container.

We use synthetic blocks of manageable size as carriers, made of ecologically beneficial polyethylene with specific surfaces of between 100 and 200 m²/m³. They are firmly locked to the tank by a high-grade steel construction. Therefore, hydraulic problems, as they are known in activated sludge systems, do not occur in this process.

Rubber membrane aerators will provide a homogeneous air ventilation, controlled by micro-PLC. Long-stretched rubber membrane aerators cause water turbulences and increase oxygen solubility. EPDM membranes prevent clogging that is common with other materials. No movable parts are underwater which increase durability and reduce maintenance.

Their shear forces will tear off the sludge flakes clinging to the fixed-bed surface and the latter will be carried to the final clarification. As is well-known from other biofilm technologies, these compact flakes settle easily. They are transferred from the final clarification tank and the preliminary clarificatory to an independent storage tank.

Sludge are stored and concentrated in tank to be constructed on site, next to the container. They can be valorised in agriculture as no chemical reagent has been used in the process.

Compared to activated sludge systems, the biofilm technology generates a smaller volume of primary and secondary sludge: 0,75 l/PE instead of 3 l/PE.

A compact system

Compact plant with simple tank designs means smaller demand in space. Conventional procedures require 0.7 m³ per person, the Zuk-O-Pur LF technology will do with 0.4 m³ per person. Substantially savings are made on real estate costs, building material and civil engineering costs.

Less sludge

Compared to conventional procedures the sludge yield is dramatically reduced. This can be even further reduced if the turbid water is re-pumped from the final to the primary clarifier. Instead of producing 3 litres per person per day, the Zuk-O-Pur LF technology will cut this volume down to 0.75 litres per person per day. This saves a lot of money, usually spent on sludge disposal.

Reliable and adaptative process

A sophisticated technique of intermittent aeration feeds the proper dosages of oxygen to the micro-organisms. Different populations of bacteria, specialised on doing various purifying jobs in the wastewater, will originate and develop. As they do not tumble around in the tank but are immobilised in and on the Zuk-O-Pur LF fixed-beds, these populations are able to adapt quickly to different conditions.

The characteristic allows the treatment of pollution loads with changing properties (flow, concentration, composition, …) and occasional slightly toxic inputs can be much better absorbed. The learning capability of the micro-organisms is enhanced, and experiences will be passed on to the following generations.

The Zuk-O-Pur LF system is also less sensitive to accidental aeration disruption.

Guarantee of a healthy environment

Mosquitoes and pestering insects that are common with other technologies are absent here. Unpleasant odours in the biological treatment stage are inexistent.

The plant generates little noise pollution (68 dBA in the technical room integrated in the container) as beside the grinder/comminutor, only a blower is required.

The excellent effluent characteristics allow the use of purified wastewater for irrigation of fields, green areas, parklands, golf courses, etc.

Aeration

One of the most important characteristics of the process is the intricate aeration system. Stationary waves and currents are created in the wastewater. Their specific shearing forces will tear off old and dead biomass while, at the same time, agitating the active biomass. The advantage is a high degree of stability and operational reliability:

Costs for electric power are cut down because of the extremely fine bubble aeration system (laser-cut tubes) and the simple, fully automatic and adapted control unit.

Functioning costs

Considering 165 PE, costs are as follows:

Electricity (network)   3,72  EUR/day

Personnel                   1,11  EUR/day

Spare parts                5,75  EUR/day

Total    10,59   EUR/day

Functioning costs: 3.864,82  EUR/year  -  23,42   EUR/PE/year

Miscellaneous

Supply includes:

Optional

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