For the anaerobic treatment of wastewater, many technologes are available, including:
Given that climate and geography of the company’s primary territory in Southeast Asia, experience has taught us that the Covered in Ground Anaerobic Reactor (CIGAR™) exceeds performance standards of other digesters in terms of:
These important aims of proper wastewater treatment systems should be considered early in the design process.
Anaerobic bacteria are nature’s methods to break down organic compounds to the base elements. In the process, suspended solids in the waste streams are converted into gases. A treatment system that contains this activity improves both water (as organic contamination is the core environmental problem of organics in the waste streams as measured by CODt and BOD5) and air (as biogas usually has constituent gases that cause odor vectors). Anaerobic reactors, if properly designed, usually are the best wastewater treatment units for breaking down VSS in the smallest available design footprint.
Consider this: “Waste is just ‘natural resources’ out-of-place”. The CODt, when removed via anaerobic activity, produces considerable energy value from each cubic meter of wastewater treated. As most of the energy is in the form of methane (at least 60% by volume), the COD removal efficiency is a key factor in the process, and to the economics of the wastewater treatment project.
Nutrients are also made available through the anaerobic process. Most wastewater contains the building blocks for plant activity including high nitrogen. Potassium and Phosphorous are found in large quantities in many wastewaters, especially those from animal farming.
Anaerobic reactors usually provide a cost effective method of wastewater treatment through higher COD removal rates than aerobic wastewater treatment methods per cubic meter of reactor volume. This will greatly reduce the construction costs of the anaerobic reactor.
Anaerobic reactors also impact operational costs positively, as methane gas generated in the process can be utilized in the process to reduce energy costs. If anaerobic reactors are the primary treatment in a system, the chemical reaction of anaerobic microbial activity will lead to reductions in the secondary treatment, or aeration. The aerators, dissolved air flotation (DAF) or other types, may be reduced or even eliminated if anaerobic reactors are operating well.
If the heating value of the biogas is of a certain level (usually 450 BTU per pound or above), the use of biogas for process steam (fuel for the boilers), or electric power conversion or cooking gas may actually result in a return on invested capital in the system.
Nutrients can be harvested as compost (if solids are preserved), or as liquid fertilizer (if maintained as totals suspended solids) have value in the marketplace.
An Ingersoll Rand a microturbine system is a complete biogas-to-energy system ready for hookup and operation. An Ingersoll Rand onsite energy system incorporates one or more rugged Ingersoll Rand microturbines, a matched fuel conditioner designed specifically for agricultural digester gas, and all necessary switchgear. Everything is completely configured at the factory for reliable operation and skid mounted for easy installation and hookup — with or without a connection to the grid.
Farms that now flare digester gas — literally wasting a valuable energy resource — may be able to simply redirect the gas from flaring to fueling a microturbine. Although anaerobic digester gas is essentially a free or lowcost fuel for a microturbine, some pretreatment of the gas is required. The integrated Ingersoll Rand fuel conditioner is designed for a wide range of biogas conditions and effectively removes hydrogen sulfide (a highly corrosive and toxic gas) and other contaminants from the gas stream. The fuel-conditioner compressor also permits the microturbine to operate at sites with low available pressure.
Ingersoll Rand Microturbine Systems
