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Off - Site Recycling

7.1 General

Off-site recycling is a commonly used alternative for PWB manufacturers as a means of managing spent etchant solutions and wastewater treatment sludges. Widespread implementation of this option reduces the quantity of wastes being disposed of in landfills. The PWB survey gathered information regarding the types of wastes sent to off-site recycling firms, quantities, destinations, and associated costs. These data are presented and discussed in this section.

A summary of data related to off-site recycling of spent process solutions, including etchants, is presented in Exhibit 7-1. Nearly all respondents reported using off-site recycling for disposing of spent process baths. A summary of data related to off-site recycling and disposal of wastewater treatment sludges is presented in Exhibit 7-2. Nearly ninety percent (90%) of those who provided data concerning the destination of their sludges indicated that they ship the sludges to recycling facilities rather than landfills.

Respondent ID	Waste Description	Source	Quantity (per year)		Available Cost Data		Name of Recycle Company	Distance to Recycle Company (miles)
279	cupric chloride	etch	11,000	gal	5.54	$/gal	Phibro Tech	40
279	cupric chloride	etch rinses	6,000	gal	5.45	$/gal	Phibro Tech	40
3023	ammoniacal	etch	199,450	gal	0.50	$/gal	Macdermid	75
3470	ammonia etch	etch	18,000	gal	nr	-	nr	nr
3470	gold plate bath	plate	60	gal	nr	-	nr	nr
6710	D001/D002	sulfuric/ peroxide	440	gal	1.96	$/gal	US Filter Rec.	40
6710	D002	ammoniacal etch	8,000	gal	1.52	$/gal	Phibro Tech	350
25503	cupric chloride	etch	2,000	gal	0.25	$/gal	Old Bridge	3,300
29710	D002/D004	etch	98,000	lb	nr	-	Macdermid	768
29710	F005/D001	paint	1,536	lb	nr	-	Safety-Kleen	100
29710	D001	solder wave	2,721	lb	nr	-	Safety-Kleen	100
29710	D001	hot air solder lev.	1,482	lb	nr	-	Safety-Kleen	100
32482	gold plating	gold plate	100	gal	nr	-	Advanced Chem	120
33089	ammoniacal etchant	etch	60,000	lb	0.29	$/lb.	US Filter Rec.	225
33089	tin/lead	solder strip	6,000	lb	0.40	$/lb.	US Filter Rec.	225
36930	etchant	etch	60,000	gal	4,000	$/yr	Phibro Tech	400
36930	microetch	etching/cleaning	6,000	gal	9,600	$/yr	-	nr
37817	flux	hot air leveler	200	gal	230	$/drum	Entech Managt.	150
37817	etchant	etch	23,000	gal	nr	-	Dexter	nr
37817	resins	cadines	15	ft3	160	$/drum	Entech Managt.	150
37817	acid sludge	waste catch drains	200	gal	230	$/drum	Entech Managt.	150
41739	D002	ammoniacal etch	17,000	gal	18,060	$/yr	Phibro Tech	400
41739	F007	gold bath	25	gal	3,000	$/yr	Technic	800
41739	D008	solder bath	20,000	lb	nr	-	Alpha Metals	800
42692	ammoniacal etchant	etch	52,883	gal	nr	-	Old Bridge	400
42751	cupric chloride	inner layer etch	83,700	gal	nr	-	Norris Environ.	1,000
42751	ammoniacal etchant	outer layer etch	32,050	gal	nr	-	Phibro Tech	1,200
43694	ammoniacal etchant	etch	35,000	gal	nr	-	S. Cal Chem	30
43841	D002	etch	13,700	gal	38,000	$/yr	Phibro Tech	500
43841	D001	oil/glycol	220	gal	2,000	$/yr	Safety Kleen	1,500
43841	class 55	board scrap	38,000	lb	7,000	$/yr	SIMCO	1,000
44486	NH etchant	Cu etch	255,370	lb	nr	-	Phibro Tech	200
44486	peroxide/sulfuric	tin strip	49,911	lb	18,135	$/yr	Phibro Tech	200
44486	flux	HAL	32,292	lb	16,000	$/yr	Hydrite	90
44486	acid Ni	Ni plate	195	lb	683	$/yr	PhibroTech	200
44657	D002/D008	etch	6,300	gal	nr	-	Hubbard Hall	nr
133000	etchant	etch	40,000	gal	0.20	$/gal	Macdermid	150
237900	ammoniacal etchant	etch	50,000	gal	0.10	$/gal	S. Cal Chem	370
237900	acid	nitric solder strip	2,000	gal	4.60	$/gal	Norris	370
237900	acid	solder strip	1,000	gal	5.00	$/gal	Norris	370
237900	acid	plating	1,400	gal	4.80	$/gal	Norris	370
358000	etchant	etch	70,000	gal	0.11	$/gal	Old Bridge, NJ	600
358000	tin stripper	tin stripper	1,800	gal	3.18	$/gal	Republic	200
462800	spent copper	etch	1,419,393	lb	26,000	$/yr1	Phibro Tech	40
462800	acid rinse water	etch	349,020	lb	0.05	$/lb	Envirite	30
462800	copper sludge	etch/microetch	12,854	lb	0.00	$/lb	Phibro Tech	40
462800	spent flux	hot air leveling	4,400	lb	0.91	$/lb	AKA Industrial	55
502100	sludge	etch	1,000	gal	nr	-	nr	nr
946587	D002	Cu sulfate plating	7,500	gal	0.12	$/lb	Learonal	980
947745	etchant	etching	3,960	gal	0.06	$/lb	Phibro Tech	250
947745	stripper	rack strip	1,200	lb	0.29	$/lb	Encycle	250
953880	D002	etch	15,000	gal	nr	-	Phibro Tech	600
955099	etchant	ammoniacal etch	65,000	gal	nr	-	Macdermid	280
955099	CuSO4	plating	12,000	gal	2.00	$/lb	Phibro Tech	400
955099	solder	HASL	22,000	lb	1.10	$/lb¹	Dexter	50
955703	etchant	etch	45,000	gal	0.18	$/lb	Phibro Tech	25
955703	solder oil	HAL solder	1,300	gal	0.40	$/lb	DK	20
955703	tin strip	tin strip	5,000	gal	0.37	$/lb	Phibro Tech	25
955703	flux	HAL solder	800	gal	0.40	$/lb	Romic	70
959951	gold	tab plate	50	gal	nr	-	Electrochemicals	nr
959951	silver	film processor	250	gal	nr	-	Electrochemicals	nr
959951	ammonia	etch	15,840	gal	nr	-	Phibro Tech	nr
965874	etchant	etch	15,800	gal	0.30	$/gal	Phibro Tech	600
36930A	etchant	etching	4,200	gal	nr	-	Phibro Tech	400
T1	gold	deep gold	nr	-	nr	-	Learonal	nr
T1	ammonical etch	inner/outer etch	nr	-	nr	-	Phibro Tech	nr
T2	etchant	Cu chloride etch	18,500	gal	3.68	$/gal	Phibro Tech	7
T2	etchant	ammoniacal etch	33,000	gal	nr	-	Phibro Tech	7
T2	tin strip	tin strip	9,000	gal	3.45	$/gal	Encycle, TX	450
T2	nitric acid	rack strip	660	gal	4.09	$/gal	Encycle, TX	450
T3	etchant	etch	8,000	gal	nr	-	S. Cal Chemical	10
T3	nitric acid	rack strip	1,000	gal	5.36	$/gal	Great West. Chem	10

¹ Income from recycled process fluid.
nr = no response
Exhibit 7-1. Off-Site Recycling of Spent Process Fluids (continued on nest page)

Respondent ID	Quantity (lbs)	Percent Solids	Recycle or Dispose	Cost ($/yr)²	Cost ($/lb)2	Company	Distance to Site (miles)
279	nr	nr	nr	nr	nr	nr	nr
29710	nr	nr	nr	nr	nr	nr	nr
31838	nr	nr	nr	nr	nr	nr	nr
36930	nr	nr	nr	nr	nr	nr	nr
43694	nr	nr	nr	nr	nr	nr	nr
237900	nr	nr	nr	nr	nr	nr	nr
358000	nr	nr	nr	nr	nr	nr	nr
955703	nr	nr	nr	nr	nr	nr	nr
3470	10,000	75	nr	nr	nr	nr	nr
965874	5,000	15	nr	nr	nr	nr	nr
25503	1,200	95	unknown	720	0.60	Norris Env	30
42692	200,000	40	unknown	85,000	0.43	S. Water Treat. Co	300
273701	300	50	D	200	0.67	US Filter Rec.	nr
36930A	18¹	50	D	nr	nr	US Filter Rec.	30
33089	80,000	35	D	48,000	0.60	US Filter Rec.	225
502100	3,000	75	R	nr	nr	nr	nr
959951	33,190	50	R	nr	nr	Cyprus Miami	nr
T2	58,000	25	R	nr	nr	Encycle, TX	450
44486	nr	nr	R	nr	nr	Foreman Metals	20
462800	12,854	98	R	0	0	Phibro Tech	40
T1	260,000	80	R	35,000	0.13	Encycle, TX	1,500
41739	42,000	65	R	6,000	0.14	Encycle, TX	600
107300	400,000	60	R	60,000	0.15	WRC	222
740500	1,700,000	36	R	275,000	0.16	WRC	1,500
55595	140,000	40	R	22,880	0.16	Envirite	400
42751	250,000	48	R	39,375	0.16	WRC	nr
133000	160,000	60	R	27,000	0.17	WRC	300
947745	9,600	80	R	1,875	0.20	Encycle, TX	250
3023	320,000	41	R	68,000	0.21	WRC	375
946587	308,000	53	R	63,150	0.21	WRC	1,000
955099	220,000	48	R	50,000	0.23	WRC	500
32482	14,000	65	R	4,000	0.29	WRC	nr
44657	8,200	30	R	3,000	0.37	WRC	750
953880	120,000	35	R	48,000	0.40	WRC	300
43841	10,000	26	R	7,800	0.78	WRC	500
6710	18,000	nr	R	25,000	1.39	WRC	850
37817	1,000	95	R	1,500	1.50	NE Chemical Co	400
T3	10,000	80	R	20,000	2.00	Encycle, TX	1,800

¹Unit is ft³.
²Some variation in costs among respondents may be due to inclusion or omission of analytical fees (sometimes referred to as material profile fees).
nr = no response
Exhibit 7-2. Off-Site Recycling/Disposal of Wastewater Treatment Sludge

7.2 Off-site Recycling of Spent Process Baths

By far, the most commonly reported spent process fluid that is sent off-site for recycling is spent etchant, particularly spent ammoniacal etchant. Spent ammoniacal etchant is created at a rate of roughly 1 gallon per 30 surface square feet of inner- and outer-layer panels. On-site regeneration of ammoniacal etchant is not widespread. One respondent reported installing solvent extraction technology for the purpose of on-site regeneration of ammoniacal etchant and copper recovery in 1994 (see Section 6.2.4). The reason that spent etchant is a popular waste for off-site recycling is due mostly to its high copper concentration, which is typically 150 g/l Cu (i.e., 15% Cu). Etchant that is sent off-site is processed to recover the copper and regenerate the etchant for reuse. Eighty-three percent (83%) of the respondents who completed the off-set recycling section of the survey reported that they send spent ammoniacal etchant off-site for recycling. Costs associated with ammoniacal etchant recycling were provided in several different types of units and varied widely, but in general, it was clear that etchant recycling represented a major portion of overall recycling costs. One respondent (ID# 462800) reported an income from off-site recycling of their spent cupric chloride etchant ($26,000 annually).

Waste products other than etchant are less frequently sent off-site for recycling by the survey respondents. The next most commonly shipped waste product is tin and/or tin-lead stripping solutions. These solutions are listed by 20% of the respondents who completed this section of the survey form. Like etchant, spent stripping solutions have a high metal concentration that makes it a viable candidate for recycling. Also, stripping solutions are generated in relatively high volumes, furthering the economics of off-site recycling. For example, ID# 44486 reported shipping 49,911 lb of tin strip and ID# T2 reported shipping 9,000 lb of tin stripper). In comparison, these quantities are equivalent to approximately 20% to 30% of their etchant volume sent off-site.

Flux, solder dross from the hot-air-solder-level process, and other lead-bearing solutions are shipped off-site for recycling by 20% of the respondents. However, the quantities of these materials that are shipped are relatively small. One exception was ID# 41739, who reported shipping 20,000 pounds of solder bath to an off-site recovery facility. Tin-lead plating baths generally have a long life-span (several years) and disposal of the solution is an unusual event. For this reason, it is believed that with this particular case, shipment was a one-time event. For example, the facility may have replaced their tin-lead plating bath with a tin-only solution or needed to dispose of a bath due to irreversible contamination.

Micro-etchants are shipped off-site for recovery by only 8% of the respondents. Spent micro-etchants typically contain copper concentrations of 15 to 30 g/l Cu (i.e., 1.5 to 3.0% Cu). Other respondents reported electrowinning these solutions on-site, or treating them with conventional precipitation.

Gold- and silver-bearing wastes are sent off-site by 15% of the respondents. Gold electroplating baths (usually gold cyanide) have a long life-span, and not surprisingly, the reported volumes were all 100 gallons or less. Solutions containing gold may include spent gold electroplating bath, or the contents of drip or drag-out tanks on the gold plating line. Silver is present in film developing fluids that may be reclaimed on-site (electrowinned), shipped off-site for metal reclamation, or combined with other waste streams and treated conventionally.

Ten percent (10%) of the respondents indicated that spent rack stripping solution is shipped off-site. Plating racks are typically coated with a non-conductive substance to prevent electroplating from occurring on the rack surface itself. Due to use, this coating may degrade and plating can accumulate on the rack, especially near the clamps and contact points. This unwanted copper deposit is removed in a stripping solution such as dilute nitric acid. The volume of spent stripping solution can be significant. Respondent T3 shipped 1,000 gallons of nitric acid rack stripper off-site at a cost of more than $5 per gallon. By comparison, this volume is equivalent to 12.5% of the etch volume shipped by the same respondent.

7.3 Wastewater Treatment Sludge

A very high percentage of respondents (88% of those providing data) indicated that they send their wastewater treatment sludge to off-site disposal facilities rather than to landfills. This percentage appears to be particularly high when compared to the 31% of plating shops that use this method for disposal (based on results presented in ref. 1).

The average and median unit costs for off-site recovery of sludge are $0.48/lb and $0.21/lb, respectively. In general, the lower costs experienced by some respondents compared to others were due to larger-size shipments and shorter distances to the recycling sites, both of which reduce transportation costs. However, in some cases, differences in unit costs may be the result of other factors. For example, ID#'s 133000 and 953880 ship similar quantities of sludge the same distance to the same recycling company.^m The unit cost of the off-site recycling for the two PWB manufacturers varies significantly ($0.17/lb vs $0.40/lb). One difference between the sludges shipped by these respondents is the percent solids. ID# 133000 is shipping a much dryer sludge (60% solids compared to 35% solids for ID# 953880). The dryer sludge will have a greater recovery value. By drying sludges PWB manufacturers can also reduce transportation costs since drying reduces the volume of the sludge. The sludge drying technology and its impact on sludge volume are discussed in Reference 1.

A discussion of off-site recycling, including descriptions of processes used by recycling companies, is presented in Reference 1.

IPC

Off - Site Recycling

7.1 General

7.2 Off-site Recycling of Spent Process Baths

7.3 Wastewater Treatment Sludge

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