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Wastewater and Sludge Treatment High Rate Sand Filter

Filtration with granular material is used in many fields as a standard process. It is used as final clean-up of the water for removing fine suspended material /particles as well as oil or grease. A special feature of our high rate filter is the nozzle-less filter bottom. The nozzle-less filter bottom ensures uniform flow in operating and during backwash and prevents loss of head in flow of both the filtered effluent and the filter wash water. Because of this, filter design is capable of treating a filtration rate up to 40 m/h (high rate). Compared to a bottom with nozzles the following design-related problems are excluded

  • During backwashing retained impurities frequently do not separate completely from the bed particles. This results in gradual, irreversible clogging of the filter bed.
  • Tendency of the fine nozzle openings to become clogged by impurities that migrate downwards during backwashing.
  • Identical detrimental effect produced by the biological slime, commonly forms in the filter.
  • These factors contribute to steady deterioration of washing in the bed segments affected, progressively aggravating the clogging problem.
  • In extreme instances this can lead to destruction of the under drain system. Our bottom system in the high rate filter prevented such nozzle related problems.

The filter medium is a special monocrystalline quartz sand of selected particle size packed in a bed of approx. 2.0 m deep on a supporting layer of 0.4 m with accurate graduated size. In conjunction with this, a high cleaning efficiency without chemicals is achieved. The filter system as proposed operates on the principle of in-depth filter. A typical High rate filter is shown below.

1. Suspended solid removal in Steel plant especially in scale pit effluent.
2. Cooling tower side stream filtration
3. RO/UF pre filtration
4. Raw water filtration
5. Tertiary treatment
6. Other filter application where suspended solid size are smaller.

Sludge Lagoon Robot - "The Predator"

GRPL have developed and constructed a unique robotic system which can handle thick viscosity sludge in various large ponds and lagoons. In addition it is capable of processing hazardous materials such as acids plus other chemicals, fuel remnants, amongst others.

GRPL's system - "The Predator" is totally capable of pumping and treating thick viscosity sludge without any need for dilution by adding other substances, and without damaging the lagoon's sealing sheets. No type of lagoon is too much; whether it is small, large, shallow or exceptionally deep. It can be mounted with different applications according to the required project.

The robot has extraordinary pumping capabilities: up to 200 m3 per hour. It is activated by remote control making it operable a safe distance away from the actual working area to protect the operators. Explosion proofing can enhance safety.

Presently the system treats 80,000 tons of concentrated phosphoric acid sludge with two units for a long term project at the "Rotem Amfert Ltd." a fertilizer and phosphate plant. In this project "The predator" can deliver pumpable sludge to a dewatering system such as high pressure filters that separate the acids from the sludge while the remaining solids are sent for dumping. The pure screened phosphoric acid is returned as a recycled raw material for end users.


Biological installations for Agriculture
GRPL builds and operates installations for the treatment of wastewater and sludge from agricultural entities like: cowsheds, olive plants etc.

The main technical components of the treatment system are:
Screw press type separators - The screw press is designed specifically for pig waste applications. Each separator unit has a capacity range of 1-2 m3/h and a yield of 30-35% dry material .

Anaerobic biological reactor
Computer controlled reactor made with corrosion resistant materials. The reactor is equipped with temperature, pH and level sensors in the basic system and can be upgraded to include other sensors such as on-line gas monitor, sludge height and TSS level sensors. The reactor is of a mesothermic type, operated at ~ 40°C. Heating coils based on hot water or steam are installed in the reactor.

Conical clarifier equipped with sedimentation enhancing plates. The clarifier is designed to allow a sufficient hydraulic retention time for optimal separation of biological particles.

Sludge circulation pumps
Circulation pumps are of positive displacement screw type pumps. These pumps do not require priming and can handle sludge solids without damage to the microscopic structure of the sludge particle.

Concrete slabs for compost curing

Biogas operated steam and/or electricity generator (Optional)

Biological installations for Industrial plants
GRPL builds and operates installations for the following industries: Food, Petro-chemical and others with unique technologies (anaerobic & aerobic treatment).

GRPL's treatment can be used to treat almost every wastewater type that contains biodegradable organic matter.

For highly concentrated organic wastewater. Less accumulation of sludge. Less energy consumption and lower land requirements. Environmentally friendly installation and energy production.

Aerobic (activated-sludge):
Treatment of hard type organic matter and wide range of organic concentrations. Biodegradable COD concentrations ranging from about 50 to 10,000 mg/l. Slow biodegradable, xenobiotic, and inhibitory materials.

Mobile treatment units for oil and fuel separation from water:
GRPL operates a unique mobile treatment unit for the purification of water polluted with oil or fuel and for the removal of water from oil and fuel sludge. The unit is based on a special centrifugal system, capable of separating oils and fuels from water. The unit is also equipped with a pre-treatment system which enables the improvement of separation and effluent quality by various physico-chemical and thermal processes. Many authorities and industrial plants are producing oily waste-water and sludge. Most plants are incapable of treating their wastewater due to lack of knowledge, or skilled manpower. Furthermore, the cost of treatment units is high relative to their economic "contribution" to the plant. The mobile treatment unit of GRPL can treat oily wastewater and fuel sludge to produce clear effluents. The client whose wastewater is being treated pays only for the treated volume and does not have to maintain or operate costly and complex treatment equipment. Furthermore, the unit is also used in cases of marine or river pollution by oils or fuels. The unit can treat the water locally and discharge clean effluents on-site, not as with the existing "treatment" methods, where a large volume of water containing small amounts of oil or fuel is pumped to be hauled to a distant disposal site. The mobile unit consists of all needed treatment facilities and is fully automatic.

Regional treatment center for industrial waste-water:
GRPL has erected a regional treatment center for industrial wastewater, which receives water from various plants and treats it according to state and local regulations. Many industrial wastewater generators do not produce sufficient volumes of wastewater to justify the installation and operation of an in-house treatment unit. The regional center serves a large number of wastewater generators, a fact which enables the economical and efficient operation of a treatment center. The cost of treatment enables the client to solve its wastewater problems with no need for massive investments or employment of excessive manpower. The treatment center includes physico-chemical treatment units that provide safe and efficient neutralization of acids and bases, cyanides and chromate, sludge treatment and oily wastewater. The toxic fraction of the wastewater, like heavy metals, is greatly reduced and is sent for burial in a special depository. The volume reduction of hazardous waste by the regional treatment center has an added value - the prevention of conveying hazardous and toxic volumes of wastewater to distant treatment centers.

Remote-Controlled Robots for Hazardous Operations:
GRPL designs, builds and operates a unique robotic machine which removes sludge and sediments from closed, complex industrial structures such as cooling towers, holding pools, lagoons, tanks and water bodies. The accumulation of sludge or sediments in these facilities reduces operational efficiency and frequently contains toxic compounds. Handling these hazardous materials in structures like cooling towers or storage tanks involves serious safety and long-term health risks for workers. The costs of "shut-down" time required for sludge removal and/or storage in tank or lagoon farms where land values are at a premium add to the problem.

With GRPL's unique, remote controlled "Sludge-Eater" the operator can work a safe distance from the actual structures from which he must dredge and/or pump sludge. Thanks to its hydraulic controls, the unit can operate fully submerged underwater or inside flammable/explosive atmospheres. This allows GRPL to remove sludge from petrochemical plants, cooling towers and oil separators as they operate. The robot is equipped with devices which enable it to work in almost any space eliminating the cost of maintenance shut-downs. The unit is rigidly built to provide powerful and robust operation under harsh conditions. Unique non-electric proximity sensors help the robot navigate around support columns and other architectural features even when the operator is unable to see them. The special propulsion unit and powerful sludge pump adapt to variations in viscosity and ensure speedy, efficient and safe completion of the task.

Dredging, jetting and cleaning equipment can be attached to accomplish all necessary maintenance in one operation.


Thermal Treatment of Hazardous Waste - Mobile Incinerators:
The transportable Waste Incineration System (TWIS) is designed to be transported to sites requiring soil remediation, destruction of hydrocarbon sludge and hazardous waste incineration. For example, it was set up on a barge and transported by the barge to the site in Alaska where the Exxon-Valdez oil tanker had run aground and released its oil cargo into the environment.

Mobile Liquid Waste Treatment Unit:
Hanna 2 is a mobile liquid waste treatment unit. The unit is capable of performing programmed or manual treatment steps of liquid waste such as acidification, reduction, chemical oxidation, coagulation/flocculation & filtration. The unit is based on a Ro-Ro platform, sized as a 20' container. This feature facilitates ease of transportation of the unit to any site in the world. The unit is operational within 3-6 hours of arrival to site.

The main features of the units are:
  • Waste pumping station
  • Treatment reactor
  • Treated liquid waste holding tank
  • Filter press
  • Chemical mixing & dosing units
  • Control buffer
  • Control room
  • Sand and activated carbon filtration for effluent polishing (Optional)

Recovering crude oil tanks
Recovering crude oil tanks through hydrothermal techniques by connecting to the existing pipes with no need for changes. This treatment will enlarge the operating volumes in a very short period (about 14 days). It is possible to achieve "gas free" conditions.

All large petrochemical and energy-producing firms have large holding tanks for heavy oils (such as crude oil, fuel oil etc.). During operation heavy sediments are being accumulated at the bottom of the tanks. These sediments have to be removed routinely in order to facilitate the proper operation of the holding tanks. During the cleaning period, the sediments are removed. This period is usually also used for tank repairs using welding equipment. This requires the tanks to be cleaned up to a gas-free state, in order to enable safe welding operations.

GRPL has developed a unique method for the economical, efficient and time saving cleaning of large holding tanks. This method employs a unique thermo-chemical process equipment, which can be operated by two workers. Using this method, crude oil tanks can be cleaned up to a gas-free state in just 2-3 weeks. The treatment unit is mobile and can be transported even to distant and hard-to-reach sites. The cost of the operation is relatively low, compared with conventional tank cleaning methods. Furthermore, this method produces a minimal volume of waste. Most of the sediment is taken out in a form, which enables the client to re-use it for refining or energy production.

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