Present Solutions for Sewage Sludge Disposal

Conventional methods of sewage sludge disposal – land filling, ocean dumping, compost and incineration – are causing irrevocable environmental damage. This is seen in the contamination of underground water reservoirs and fertile land, the pollution of oceans and the emission of hazardous gases into the air. Sludge fertilizer is already banned in several European countries. The move is in response to growing concern about residues in the sludge, particularly synthetic hormones and some pharmaceutical compounds. Today, an average of 40% sludge is used in agriculture with the rest being incinerated.

Changing regulations are the catalyst driving the wastewater and sludge treatment market. These regulations are driving the end-users to search for final treatment methods other than incineration, agricultural use, landfills and ocean dumping. Due to a decrease in the disposal sites for industrial and municipal sludge, and due to national and international regulations, it will soon be more common to reuse primary and secondary sludge as a sustainable energy source, such as fuel for industrial plants.

Pyrolysis and gasification, like incineration, are options for recovering value from sewage sludge by thermal treatment. Both pyrolysis and gasification turn sewage sludge into energy-rich fuels by heating the sludge under controlled conditions. Whereas incineration fully converts the input sewage sludge into energy and ash, these processes deliberately limit the conversion so that combustion does not take place directly. Instead, they convert the sewage sludge into valuable intermediates that can be further processed for materials recycling or energy recovery.

Pyrolysis and gasification offer more scope for recovering products from sewage sludge than incineration. When sludge is burnt in a modern incineration the only practical product is energy, whereas the gases, oils and solid char from pyrolysis and gasification can not only be used as fuel, but also purified and used as a feedstock for petrochemicals and other applications. Obviously, there is a growing demand for sludge management technologies capable of: 1). Meeting increasingly stringent regulatory requirements. 2.) Effectively utilizing potential for material and/or energy recovery.

The BioPetrol Solution

Measures to be implemented to resolve the problem of sewage sludge that contain a high degree of organic matter could primarily aim at recycling it through a thermo chemical pyrolysis process in order to recover hydrocarbons that make up the structure of sewage sludge. Pyrolysis of sewage sludge produces oil, gas and char products. The pyrolysis oils have also been shown to contain valuable chemicals in significant concentrations and hence may have the potential to be used as chemical feedstock. The production of a liquid product increases the ease of handling, storage and transport.

The technology, vastly improved by BioPetrol (US patent 7276148) from the original Fischer - Tropsh technology, is capable of processing carbon wastes, other than sewage sludge, including agri-wastes, bagasse, pulp and paper residues, tannery sludge and other end-of-life products such as plastics, tires and the organics in municipal solid waste.

The process of low temperature thermochemical conversion of municipal sewage sludge to oil is a new technology in developed countries. The amount of investment is still less than the amount invested in the sewage sludge incineration process, and the operational economy of the process is obviously superior to incineration.

The BioPetrol, Ltd. integrated thermochemical process recovers about 1,100,000 Kcal from each 283 kg of sewage sludge 90% dry solids (D.S.) after the thermal evaporating of 717kg water from each dewatered ton (1,000 kg) of sewage sludge 26% D.S.

The BioPetrol process begins with sewage sludge at 90% D.S. Sewage sludge drying equipment is used commonly for the evaporative removal of interstitial water from the sludge. Numerous drying technologies exist on the market.

Market Analysis and Strategy

Three potential products/services:

1. Disposal of Sewage Sludge – Disposal of sewage sludge comprises over 30% of wastewater treatment plants’ budget. Customers of this service are local communities. They are willing to pay top dollar for the disposal of their sludge. In-State tipping fees averages $78/ton and out-of state $94/ton and more (Commission to study methods and cost of sewage sludge disposal - Final Report 2008). The US produces 29 million tons of sludge annually (2009).

2. Synthetic Crude Oil – One ton dry sludge produces 425 Kg oil, a drop-in fuel for heavy industry. Oil energy = 5,850Kcal/Kg. The amount of excess oil available for external use depends on the method used to dry the 26% D.S. feedstock to 85% D.S. There are references in professional literature to numerous valuable chemicals in significant concentration that are present in pyrolysis oils.

BioPetrol Ltd has on board, as a shareholder, an internationally renowned scientist-academician to address this issue.

3. Selling the Technology - With the completion of the Commercial Demonstration Plant, BioPetrol. Ltd. will have the technology to sell to world markets. Potential markets are water authorities, municipalities, wastewater treatment plants, entrepreneurs, sewage sludge disposal contractors, sludge drying operators.

BioPetrol, ltd. has been awarded a grant of $300,000 for a period of 2 years by Israel’s Office of the Chief Scientist and a $400,000 (not used) grant from the Israel Water Authority to conduct advanced R&D. The company has concluded and proved the viability of the process and is now on the verge of constructing a demonstration pilot for a continuous process.

BioPetrol is seeking $2MM Venture Capital, or $1MM industrial partner* for construction of a Commercial Demonstration Plant. A business plan is available for further details.

* Qualified for a matching fund by the BIRD Foundation – Binational Industrial R&D cooperation between Israel & US governments.

Technology

The technological processes at issue in the Bio-Petrol project belong to the sphere of liquefying carbon-rich solid fuels. The liquefaction processes common today comprise two stages:

1. Thermal breakdown of the molecular structure to create radical fractions different in size.

2. Stabilization of the radicals by recombining themselves or by redistribution of hydrogen from the raw material itself or by hydrogen that is introduced from outside (molecular hydrogen or from hydrogen-donor matter).

Bio-Petrol Company has carried out R&D work which has resulted in the formulation of a suitable process i.e. BioPetrol patent for producing synthetic oil from sewage sludge with larger output than that obtained from the common process-i.e. pyrolysis (Fischer- Tropsh process). By integrating familiar liquefaction methods the company developed a process of high utilization of the organic matter that is in the sewage sludge that produces oil and gas in larger quantities and of better quality.

Project Team

Dr. Yafim Plopski – Chief Scientist
Holds a Ph.D in chemical and technology of fuels. Over 30 years experience in the field of oil and petrochemical recovery technology in both Russia and Israel. Has 40 relevant publications and patents on the subject.

Professional Board

Dr. Amit Mor – Received his Ph.D in economics, energy and the environment from Pennsylvania State University. Was the consultant to the World Bank in Washington for energy and environment infrastructure projects and in policy planning for reforms in the environment, electricity, oil and natural gas.